1
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Arbour J, Rumpp F, López-Fernández H. Organismal form constrains the evolution of complex lever systems in Neotropical cichlid four-bar linkages. Anat Rec (Hoboken) 2024; 307:81-96. [PMID: 37102462 DOI: 10.1002/ar.25231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 04/05/2023] [Accepted: 04/12/2023] [Indexed: 04/28/2023]
Abstract
The diversification of functional traits may be limited by the intrinsic constraints of organismal form (i.e., constructional constraints), owing to the differential investment in different anatomical structures. In this study, we test whether overall organismal form impacts the evolution of shape and function in complex lever systems. We examined the relationship between four-bar shape and overall head shape in two four-bar linkage systems: the oral-jaw and hyoid-neurocranium systems in Neotropical cichlids. We also investigated the strength of form-function mapping in these four-bar linkages and the impact of constraining head shape on these correlations. We quantified the shape of the head and two four-bar linkages using geometric morphometrics and compared these with the kinematic transmission coefficient of each linkage system. The shapes of both linkages were strongly correlated with their mechanical properties, and head shape appears to constrain the shape of both four-bar linkages. Head shape induced greater integration between the two linkages, was associated with stronger form-function correlations and higher rates of evolution in biomechanically important features. Head shape constraints may also contribute to a weak but significant trade-off in linkage kinematics. Elongation of the head and body, in particular, appears to minimize the impact of this trade-off, possibly through maximizing anterior-posterior space availability. However, the strength of relationships between shape and function, and the impact of head shape differed between the two linkages, with the hyoid four-bar in general showing stronger form-function relationships despite being more independent from head shape constraints.
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Affiliation(s)
- Jessica Arbour
- Department of Biology, Middle Tennessee State University, Murfreesboro, Tennessee, USA
| | - Faith Rumpp
- Department of Biology, Middle Tennessee State University, Murfreesboro, Tennessee, USA
| | - Hernán López-Fernández
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan, USA
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2
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Abecia JE, Luiz OJ, Crook DA, Banks SC, Wedd D, King AJ. Sex and male breeding state predict intraspecific trait variation in mouth-brooding fishes. JOURNAL OF FISH BIOLOGY 2022; 101:550-559. [PMID: 35638470 PMCID: PMC9544576 DOI: 10.1111/jfb.15122] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 05/25/2022] [Indexed: 06/15/2023]
Abstract
Sex-specific reproductive roles contribute to sexual dimorphic morphological trait variations. In uniparental mouth-brooding fishes, the mouth performs a reproductive function in addition to its key roles in feeding and respiration, resulting in the potential for sex-specific functional performance trade-offs. Trait differences related to parental care may occur when the individual matures or be restricted to periods when the parent is mouth-brooding. This study explored sexual dimorphism and morphological trait adaptations related to feeding, breeding, respiration and locomotion performance in two paternal mouth-brooding freshwater fishes (Glossamia aprion and Neoarius graeffei). Eight morphological traits were evaluated for sexual dimorphism (non-brooder males vs. females) and male breeding state differences (brooders vs. non-brooders). Male breeding state was a significant predictor of trait variation in both species. Brooders differed in buccal volume and in several feeding and locomotory traits compared to non-brooder males. Non-brooder males had bigger buccal volumes and relative eye diameters (G. aprion) and larger relative gape sizes (N. graeffei) compared to females, a potential response to both mouth-brooding and feeding requirements. Although there were clear trait differences between brooder and non-brooder males, further research is required to confirm whether individuals return to their former morphology once mouth-brooding has ceased or if trait differences are maintained post-brooding. This study highlights the importance of considering the potential impacts of intraspecific trait variation on the performance of critical life functions, such as feeding, respiration and locomotion across the life history.
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Affiliation(s)
- Janine E. Abecia
- Research Institute for the Environment and LivelihoodsCharles Darwin UniversityCasuarinaNorthern TerritoryAustralia
| | - Osmar J. Luiz
- Research Institute for the Environment and LivelihoodsCharles Darwin UniversityCasuarinaNorthern TerritoryAustralia
| | - David A. Crook
- Research Institute for the Environment and LivelihoodsCharles Darwin UniversityCasuarinaNorthern TerritoryAustralia
- Centre for Freshwater EcosystemsLa Trobe UniversityAlburyVictoriaAustralia
| | - Sam C. Banks
- Research Institute for the Environment and LivelihoodsCharles Darwin UniversityCasuarinaNorthern TerritoryAustralia
| | - Dion Wedd
- Research Institute for the Environment and LivelihoodsCharles Darwin UniversityCasuarinaNorthern TerritoryAustralia
| | - Alison J. King
- Research Institute for the Environment and LivelihoodsCharles Darwin UniversityCasuarinaNorthern TerritoryAustralia
- Centre for Freshwater EcosystemsLa Trobe UniversityAlburyVictoriaAustralia
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3
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DeLorenzo L, DeBrock V, Carmona Baez A, Ciccotto PJ, Peterson EN, Stull C, Roberts NB, Roberts RB, Powder KE. Morphometric and Genetic Description of Trophic Adaptations in Cichlid Fishes. BIOLOGY 2022; 11:biology11081165. [PMID: 36009792 PMCID: PMC9405370 DOI: 10.3390/biology11081165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 07/28/2022] [Accepted: 07/30/2022] [Indexed: 11/16/2022]
Abstract
Since Darwin, biologists have sought to understand the evolution and origins of phenotypic adaptations. The skull is particularly diverse due to intense natural selection on feeding biomechanics. We investigated the genetic and molecular origins of trophic adaptation using Lake Malawi cichlids, which have undergone an exemplary evolutionary radiation. We analyzed morphological differences in the lateral and ventral head shape among an insectivore that eats by suction feeding, an obligate biting herbivore, and their F2 hybrids. We identified variation in a series of morphological traits—including mandible width, mandible length, and buccal length—that directly affect feeding kinematics and function. Using quantitative trait loci (QTL) mapping, we found that many genes of small effects influence these craniofacial adaptations. Intervals for some traits were enriched in genes related to potassium transport and sensory systems, the latter suggesting co-evolution of feeding structures and sensory adaptations for foraging. Despite these indications of co-evolution of structures, morphological traits did not show covariation. Furthermore, phenotypes largely mapped to distinct genetic intervals, suggesting that a common genetic basis does not generate coordinated changes in shape. Together, these suggest that craniofacial traits are mostly inherited as separate modules, which confers a high potential for the evolution of morphological diversity. Though these traits are not restricted by genetic pleiotropy, functional demands of feeding and sensory structures likely introduce constraints on variation. In all, we provide insights into the quantitative genetic basis of trophic adaptation, identify mechanisms that influence the direction of morphological evolution, and provide molecular inroads to craniofacial variation.
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Affiliation(s)
- Leah DeLorenzo
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA
| | - Victoria DeBrock
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA
| | - Aldo Carmona Baez
- Department of Biological Sciences and Genetics and Genomics Academy, North Carolina State University, Raleigh, NC 27695, USA
| | - Patrick J Ciccotto
- Department of Biological Sciences and Genetics and Genomics Academy, North Carolina State University, Raleigh, NC 27695, USA
- Department of Biology, Warren Wilson College, Swannanoa, NC 28778, USA
| | - Erin N Peterson
- Department of Biological Sciences and Genetics and Genomics Academy, North Carolina State University, Raleigh, NC 27695, USA
| | - Clare Stull
- Department of Biological Sciences and Genetics and Genomics Academy, North Carolina State University, Raleigh, NC 27695, USA
| | - Natalie B Roberts
- Department of Biological Sciences and Genetics and Genomics Academy, North Carolina State University, Raleigh, NC 27695, USA
| | - Reade B Roberts
- Department of Biological Sciences and Genetics and Genomics Academy, North Carolina State University, Raleigh, NC 27695, USA
| | - Kara E Powder
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA
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4
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Abstract
Whole genome sequences are beginning to revolutionize our understanding of phylogenetic relationships. Yet, even whole genome sequences can fail to resolve the evolutionary history of the most rapidly radiating lineages, where incomplete lineage sorting, standing genetic variation, introgression, and other factors obscure the phylogenetic history of the group. To overcome such challenges, one emerging strategy is to integrate results across different methods. Most such approaches have been implemented on reduced representation genomic data sets, but whole genomes should provide the maximum possible evidence approach. Here, we test the ability of single nucleotide polymorphisms extracted from whole genome resequencing data, implemented in an integrative genomic approach, to resolve key nodes in the phylogeny of the mbuna, rock-dwelling cichlid fishes of Lake Malaŵi, which epitomize the phylogenetic intractability that often accompanies explosive lineage diversification. This monophyletic radiation has diversified at an unparalleled rate into several hundred species in less than 2 million years. Using an array of phylogenomic methods, we consistently recovered four major clades of mbuna, but a large basal polytomy among them. Although introgression between clades apparently contributed to the challenge of phylogenetic reconstruction, reduction of the data set to nonintrogressed sites still did not help to resolve the basal polytomy. On the other hand, relationships among six congeneric species pairs were resolved without ambiguity, even in one case where existing data led us to predict that resolution would be difficult. We conclude that the bursts of diversification at the earliest stages of the mbuna radiation may be phylogenetically unresolvable, but other regions of the tree are phylogenetically clearly supported. Integration of multiple phylogenomic approaches will continue to increase confidence in relationships inferred from these and other whole-genome data sets. [Incomplete lineage sorting; introgression; linkage disequilibrium; multispecies coalescence; rapid radiation; soft polytomy.]
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5
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Arbour JH, Curtis AA, Santana SE. Sensory adaptations reshaped intrinsic factors underlying morphological diversification in bats. BMC Biol 2021; 19:88. [PMID: 33931060 PMCID: PMC8086122 DOI: 10.1186/s12915-021-01022-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 04/01/2021] [Indexed: 11/13/2022] Open
Abstract
Background Morphological evolution may be impacted by both intrinsic (developmental, constructional, physiological) and extrinsic (ecological opportunity and release) factors, but can intrinsic factors be altered by adaptive evolution and, if so, do they constrain or facilitate the subsequent diversification of biological form? Bats underwent deep adaptive divergences in skull shape as they evolved different sensory modes; here we investigate the potential impact of this process on two intrinsic factors that underlie morphological variation across organisms, allometry, and modularity. Results We use comparative phylogenetic and morphometric approaches to examine patterns of evolutionary allometry and modularity across a 3D geometric morphometric dataset spanning all major bat clades. We show that allometric relationships diverge between echolocators and visually oriented non-echolocators and that the evolution of nasal echolocation reshaped the modularity of the bat cranium. Conclusions Shifts in allometry and modularity may have significant consequences on the diversification of anatomical structures, as observed in the bat skull.
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Affiliation(s)
- J H Arbour
- Present Address: Department of Biology, Middle Tennessee State University, Murfreesboro, TN, 37132, USA.,Department of Biology, University of Washington, Seattle, Washington, 98195, USA
| | - A A Curtis
- Department of Biology, University of Washington, Seattle, Washington, 98195, USA
| | - S E Santana
- Department of Biology, University of Washington, Seattle, Washington, 98195, USA. .,Burke Museum of Natural History and Culture, University of Washington, Seattle, Washington, 98195, USA.
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6
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Lloyd E, Chhouk B, Conith AJ, Keene AC, Albertson RC. Diversity in rest-activity patterns among Lake Malawi cichlid fishes suggests a novel axis of habitat partitioning. J Exp Biol 2021; 224:238727. [PMID: 33658242 PMCID: PMC8077532 DOI: 10.1242/jeb.242186] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 02/11/2021] [Indexed: 12/04/2022]
Abstract
Animals display remarkable diversity in rest and activity patterns that are regulated by endogenous foraging strategies, social behaviors and predator avoidance. Alteration in the circadian timing of activity or the duration of rest–wake cycles provide a central mechanism for animals to exploit novel niches. The diversity of the >3000 cichlid species throughout the world provides a unique opportunity to examine variation in locomotor activity and rest. Lake Malawi alone is home to over 500 species of cichlids that display divergent behaviors and inhabit well-defined niches throughout the lake. These species are presumed to be diurnal, though this has never been tested systematically. Here, we measured locomotor activity across the circadian cycle in 11 Lake Malawi cichlid species. We documented surprising variability in the circadian time of locomotor activity and the duration of rest. In particular, we identified a single species, Tropheops sp. ‘red cheek’, that is nocturnal. Nocturnal behavior was maintained when fish were provided shelter, but not under constant darkness, suggesting that it results from acute response to light rather than an endogenous circadian rhythm. Finally, we showed that nocturnality is associated with increased eye size after correcting for evolutionary history, suggesting a link between visual processing and nighttime activity. Together, these findings identify diversity of locomotor behavior in Lake Malawi cichlids and provide a system for investigating the molecular and neural basis underlying variation in nocturnal activity. Summary: Cichlids show a remarkable diversity in morphology and behavior. Cichlid species exhibit differences in strength and polarity of activity rhythms, revealing a new axis of habitat partitioning.
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Affiliation(s)
- Evan Lloyd
- Department of Biological Science, Florida Atlantic University, Jupiter, FL 33401, USA
| | - Brian Chhouk
- Department of Biology, University of Massachusetts, Amherst, MA 01003, USA
| | - Andrew J Conith
- Department of Biology, University of Massachusetts, Amherst, MA 01003, USA
| | - Alex C Keene
- Department of Biological Science, Florida Atlantic University, Jupiter, FL 33401, USA
| | - R Craig Albertson
- Department of Biology, University of Massachusetts, Amherst, MA 01003, USA
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7
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Munyandamutsa PS, Jere WL, Kassam D, Mtethiwa A. Trophic divergence of Lake Kivu cichlid fishes along a pelagic versus littoral habitat axis. Ecol Evol 2021; 11:1570-1585. [PMID: 33613990 PMCID: PMC7882941 DOI: 10.1002/ece3.7117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 11/05/2020] [Accepted: 11/06/2020] [Indexed: 01/16/2023] Open
Abstract
Local adaptation to the littoral and pelagic zones in two cichlid haplochromine fish species from Lake Kivu was investigated using morphometrics. Cranial variation and inferred jaw mechanics in both sexes of the two species across the two habitat types were quantified and compared. Comparisons of littoral versus pelagic populations revealed habitat-specific differences in the shape of the feeding apparatus. Also, kinematic transmission of the anterior jaw four-bar linkage that promotes greater jaw protrusion was higher in the pelagic zone than in the littoral zone for both species. Inferred bite force was likewise higher in pelagic zone fish. There were also sex-specific differences in craniofacial morphology as males exhibited longer heads than females in both habitats. As has been described for other cichlids in the East African Great Lakes, local adaptation to trophic resources in the littoral and pelagic habitats characterizes these two Lake Kivu cichlids. Similar studies involving other types of the Lake Kivu fishes are recommended to test the evidence of the observed trophic patterns and their genetic basis of divergences.
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Affiliation(s)
- Philippe S. Munyandamutsa
- Africa Centre of Excellence in Aquaculture and Fisheries ScienceDepartment of Aquaculture and Fisheries ScienceBunda CollegeLilongwe University of Agriculture and Natural ResourcesLilongweCentreMalawi
- Department of Animal ProductionCollege of Agriculture, Animal Sciences and Veterinary MedicineUniversity of RwandaKK 737MusanzeNorthRwanda
| | - Wilson L. Jere
- Africa Centre of Excellence in Aquaculture and Fisheries ScienceDepartment of Aquaculture and Fisheries ScienceBunda CollegeLilongwe University of Agriculture and Natural ResourcesLilongweCentreMalawi
| | - Daud Kassam
- Africa Centre of Excellence in Aquaculture and Fisheries ScienceDepartment of Aquaculture and Fisheries ScienceBunda CollegeLilongwe University of Agriculture and Natural ResourcesLilongweCentreMalawi
| | - Austin Mtethiwa
- Africa Centre of Excellence in Aquaculture and Fisheries ScienceDepartment of Aquaculture and Fisheries ScienceBunda CollegeLilongwe University of Agriculture and Natural ResourcesLilongweCentreMalawi
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8
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Santos-Santos JH, Audenaert L, Verheyen E, Adriaens D. Ontogenetic divergence generates novel phenotypes in hybrid cichlids. J Anat 2021; 238:1116-1127. [PMID: 33417249 PMCID: PMC8053579 DOI: 10.1111/joa.13375] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 11/10/2020] [Accepted: 11/16/2020] [Indexed: 12/20/2022] Open
Abstract
Hybridization is suggested to contribute to ecomorphological and taxonomic diversity in lacustrine East African cichlids. This is supported by studies demonstrating that genetic diversity within lake radiations has been influenced by hybridization events, leading to extensive phenotypic differentiation of genetically closely related species. Hybrid persistence and speciation in sympatry with gene flow can be explained by pleiotropy in traits involved in reproductive isolation; however, little attention has been given to how trait differentiation is established during hybrid ontogeny, and how this may relate to trophic and locomotor specialization. This study compares body shape changes in a Lake Victoria cichlid hybrid throughout its post-hatch ontogeny to those of its parental species. Across the considered age/size categories, hybrids occupy a distinct and intermediate morphological space, yet where several transgressive traits emerge. A between-group principal component analysis on body shapes across size categories reveals axes of shape variation exclusive to the hybrids in the youngest/smallest size categories. Shape differences in the hybrids involved morphological traits known to be implicated in trophic and locomotor specializations in the parental species. Combined, our findings suggest that phenotypic divergence in the hybrid can lead to functional differences that may potentially release them to some degree from competition with the parental species. These findings agree with recent literature that addresses the potential importance of hybridization for the unusually recent origin of the Lake Victoria cichlid super-species flock.
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Affiliation(s)
- Javier H Santos-Santos
- Evolutionary Morphology of Vertebrates, Ghent University, Gent, Belgium.,Department of Biogeography and Global Change, Museo Nacional de Ciencias Naturales, Consejo Superior de Investigaciones Científicas (MNCN-CSIC), Madrid, Spain
| | - Leen Audenaert
- OD Taxonomy and Phylogeny, Vertebrates, Royal Belgian Institute of Natural Sciences, Brussels, Belgium
| | - Erik Verheyen
- OD Taxonomy and Phylogeny, Vertebrates, Royal Belgian Institute of Natural Sciences, Brussels, Belgium.,Evolutionary Ecology Group, Biology Department, University of Antwerp, Antwerp, Belgium
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9
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Burress ED, Wainwright PC. A peacock bass (Cichla) functional novelty relaxes a constraint imposed by the classic cichlid pharyngeal jaw innovation. Biol J Linn Soc Lond 2020. [DOI: 10.1093/biolinnean/blaa050] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Abstract
Innovations may provide access to new resources but often result in significant trade-offs. Pharyngognathy is a classic pharyngeal jaw innovation in which the left and right lower pharyngeal jaw (LPJ) bones are united into a single structure, producing a strong bite but reduced gape. Throughout cichlids, pharyngeal suturing occurs along the entire medial border between LPJ bones, except in peacock bass (Cichla), where these bones are connected by ligaments only in their anterior region. We show that this limited attachment permits the jaw bones to spread apart and we link this feature to an increase in pharyngeal gape that is comparable to non-pharyngognathous species. The capacity of the LPJ bones to spread apart is strongest in juveniles and is mostly lost during development. Juvenile Cichla exhibit size-specific pharyngeal gape similar to non-pharyngognathous percomorphs; however, adults exhibit pharyngeal gape on par with other predatory cichlids. Relaxation of pharyngeal suturing offsets a major deleterious consequence of pharyngognathy by reducing gape limitation and we propose this may accelerate the ontogenetic transition to piscivory. Partial reversal of the classic cichlid pharyngeal jaw innovation highlights the functional trade-offs that often accompany innovations and may be a major cause of variation in their macroevolutionary consequences.
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Affiliation(s)
- Edward D Burress
- Department of Evolution and Ecology, University of California, Davis, CA, USA
| | - Peter C Wainwright
- Department of Evolution and Ecology, University of California, Davis, CA, USA
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10
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Ecomorphology, trophic niche, and distribution divergences of two common damselfishes in the Gulf of California. C R Biol 2019; 342:309-321. [PMID: 31784218 DOI: 10.1016/j.crvi.2019.11.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 11/05/2019] [Accepted: 11/05/2019] [Indexed: 11/22/2022]
Abstract
Damselfishes of the genus Stegastes are among the most conspicuous benthic reef-associated fish in the Gulf of California, and the two most commonly found species are the Beaubrummel Gregory Stegastes flavilatus and the Cortez damselfish Stegastes rectifraenum. Both species are described as ecologically and morphologically very similar. However, the niche theory predicts that coexisting species will tend to minimize competition through niche partitioning. We, therefore, investigated the degree of their ecological similarity through their morphology, trophic ecology, and spatial distribution, as well as, the effects of environmental variables on their abundance. We showed that S. rectifraenum is highly abundant in the entire Gulf of California while S. flavilatus is only found in the central and southern part. The abundance of S. rectifraenum was higher in shallow water and decreased when the cover of macroalgae and sand increased. No environmental variable was related to the abundance of S. flavilatus. Both species had distinct isotopic niches: S. flavilatus fed almost exclusively on plankton and zoobenthos, while S. rectifraenum had an omnivorous diet mixing turf, zoobenthos and plankton. The diet divergence was reflected in the morphology of the two species. Stegastes flavilatus had a more rounded body shape, with a higher supraoccipital crest and more gill rakers than S. rectifraenum, which may increase its ability to feed on vagile invertebrates and zooplankton. Our results support the hypothesis that a niche partition has occurred between the two species. Furthermore, the importance of planktonic food sources to both species, considered as benthic territorial feeders, challenges the traditional ecological description of the Stegastes species.
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11
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Conith MR, Conith AJ, Albertson RC. Evolution of a soft-tissue foraging adaptation in African cichlids: Roles for novelty, convergence, and constraint. Evolution 2019; 73:2072-2084. [PMID: 31418824 DOI: 10.1111/evo.13824] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 06/25/2019] [Accepted: 07/05/2019] [Indexed: 12/12/2022]
Abstract
Understanding the origins of biodiversity demands consideration of both extrinsic (e.g., ecological opportunity) and intrinsic (e.g., developmental constraint) factors. Here, we use a combination of phylogenetic and genetic tools to address the origin of novelty in African cichlids. In particular, we focus on an extreme hypertrophied snout that is structurally integrated with the upper jaw. We show that this bizarre trait has evolved independently in at least two distinct and ecologically successful cichlid clades. We find that snout dimensions are decoupled both phenotypically and genetically, which has enabled it to evolve independently in multiple directions. Further, patterns of variation among species and within a genetic mapping pedigree suggest that relative to snout length, depth is under greater genetic and/or developmental constraint. Models of evolution suggest that snout shape is under selection for feeding behavior, with snout depth being important for algae scraping and snout length for sand sifting. Indeed, the deep snout of some algivores is achieved via an expansion of the intermaxillary ligament, which is important for jaw stability and may increase feeding performance. Overall, our data imply that the evolution of exaggerated snout depth required overcoming a genetic/developmental constraint, which led to expanded ecological opportunity via foraging adaptation.
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Affiliation(s)
- Moira R Conith
- Graduate Program in Organismic and Evolutionary Biology, University of Massachusetts, Amherst, Massachusetts, 01003
| | - Andrew J Conith
- Department of Biology, University of Massachusetts, Amherst, Massachusetts, 01003
| | - R Craig Albertson
- Graduate Program in Organismic and Evolutionary Biology, University of Massachusetts, Amherst, Massachusetts, 01003.,Department of Biology, University of Massachusetts, Amherst, Massachusetts, 01003
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12
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Conith AJ, Lam DT, Albertson RC. Muscle-induced loading as an important source of variation in craniofacial skeletal shape. Genesis 2018; 57:e23263. [PMID: 30418689 DOI: 10.1002/dvg.23263] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 10/25/2018] [Accepted: 10/27/2018] [Indexed: 01/01/2023]
Abstract
The shape of the craniofacial skeleton is constantly changing through ontogeny and reflects a balance between developmental patterning and mechanical-load-induced remodeling. Muscles are a major contributor to producing the mechanical environment that is crucial for "normal" skull development. Here, we use an F5 hybrid population of Lake Malawi cichlids to characterize the strength and types of associations between craniofacial bones and muscles. We focus on four bones/bone complexes, with different developmental origins, alongside four muscles with distinct functions. We used micro-computed tomography to extract 3D information on bones and muscles. 3D geometric morphometrics and volumetric measurements were used to characterize bone and muscle shape, respectively. Linear regressions were performed to test for associations between bone shape and muscle volume. We identified three types of associations between muscles and bones: weak, strong direct (i.e., muscles insert directly onto bone), and strong indirect (i.e., bone is influenced by muscles without a direct connection). In addition, we show that although the shape of some bones is relatively robust to muscle-induced mechanical stimulus, others appear to be highly sensitive to muscular input. Our results imply that the roles for muscular input on skeletal shape extend beyond specific points of origin or insertion and hold significant potential to influence broader patterns of craniofacial geometry. Thus, changes in the loading environment, either as a normal course of ontogeny or if an organism is exposed to a novel environment, may have pronounced effects on skeletal shape via near and far-ranging effects of muscular loading.
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Affiliation(s)
- Andrew J Conith
- Biology Department, University of Massachusetts Amherst, Amherst, Massachusetts
| | - Daniel T Lam
- Biology Department, University of Massachusetts Amherst, Amherst, Massachusetts
| | - R Craig Albertson
- Biology Department, University of Massachusetts Amherst, Amherst, Massachusetts
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13
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Hulsey CD, Holzman R, Meyer A. Dissecting a potential spandrel of adaptive radiation: Body depth and pectoral fin ecomorphology coevolve in Lake Malawi cichlid fishes. Ecol Evol 2018; 8:11945-11953. [PMID: 30598789 PMCID: PMC6303698 DOI: 10.1002/ece3.4651] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Revised: 09/22/2018] [Accepted: 10/01/2018] [Indexed: 01/11/2023] Open
Abstract
The evolution of body shape reflects both the ecological factors structuring organismal diversity as well as an organism's underlying anatomy. For instance, body depth in fishes is thought to determine their susceptibility to predators, attractiveness to mates, as well as swimming performance. However, the internal anatomy influencing diversification of body depth has not been extensively examined, and changes in body depth could arise as a by-product of functional changes in other anatomical structures. Using an improved phylogenetic hypothesis for a diverse set of Lake Malawi cichlid fishes, we tested the evolutionary association between body depth and the height of the pectoral girdle. To refine the functional importance of the observed substantial correlation, we also tested the coevolution of pectoral girdle height and pectoral fin area. The extensive coevolution of these traits suggests body depth in fishes like the Lake Malawi cichlids could diverge simply as a by-product of being tightly linked to ecomorphological divergence in other functional morphological structures like the pectoral fins.
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Affiliation(s)
| | - Roi Holzman
- School of Zoology, Faculty of Life scienceTel Aviv University, Tel Aviv, Israel and The Inter‐University Institute for Marine SciencesEilatIsrael
| | - Axel Meyer
- Department of BiologyUniversity of KonstanzKonstanzGermany
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14
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Darrin Hulsey C, Zheng J, Holzman R, Alfaro ME, Olave M, Meyer A. Phylogenomics of a putatively convergent novelty: did hypertrophied lips evolve once or repeatedly in Lake Malawi cichlid fishes? BMC Evol Biol 2018; 18:179. [PMID: 30486792 PMCID: PMC6263179 DOI: 10.1186/s12862-018-1296-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 11/16/2018] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Phylogenies provide critical information about convergence during adaptive radiation. To test whether there have been multiple origins of a distinctive trophic phenotype in one of the most rapidly radiating groups known, we used ultra-conserved elements (UCEs) to examine the evolutionary affinities of Lake Malawi cichlids lineages exhibiting greatly hypertrophied lips. RESULTS The hypertrophied lip cichlids Cheilochromis euchilus, Eclectochromis ornatus, Placidochromis "Mbenji fatlip", and Placidochromis milomo are all nested within the non-mbuna clade of Malawi cichlids based on both concatenated sequence and single nucleotide polymorphism (SNP) inferred phylogenies. Lichnochromis acuticeps that exhibits slightly hypertrophied lips also appears to have evolutionary affinities to this group. However, Chilotilapia rhoadesii that lacks hypertrophied lips was recovered as nested within the species Cheilochromis euchilus. Species tree reconstructions and analyses of introgression provided largely ambiguous patterns of Malawi cichlid evolution. CONCLUSIONS Contrary to mitochondrial DNA phylogenies, bifurcating trees based on our 1024 UCE loci supported close affinities of Lake Malawi lineages with hypertrophied lips. However, incomplete lineage sorting in Malawi tends to render these inferences more tenuous. Phylogenomic analyses will continue to provide powerful inferences about whether phenotypic novelties arose once or multiple times during adaptive radiation.
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Affiliation(s)
- C. Darrin Hulsey
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Jimmy Zheng
- Department of Ecology & Evolutionary Biology, University of California, Los Angeles, CA USA
| | - Roi Holzman
- Department of Zoology, Tel Aviv University and the Inter-University Institute for Marine Sciences in Eilat, 88103 Eilat, Israel
| | - Michael E. Alfaro
- Department of Ecology & Evolutionary Biology, University of California, Los Angeles, CA USA
| | - Melisa Olave
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Axel Meyer
- Department of Biology, University of Konstanz, Konstanz, Germany
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15
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Thompson M, Van Wassenbergh S, Rogers SM, Seamone SG, Higham TE. Angling-induced injuries have a negative impact on suction feeding performance and hydrodynamics in marine shiner perch, Cymatogaster aggregata. ACTA ACUST UNITED AC 2018; 221:221/19/jeb180935. [PMID: 30301821 DOI: 10.1242/jeb.180935] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 08/06/2018] [Indexed: 11/20/2022]
Abstract
Fishing is a popular and lucrative sport around the world and, in some cases, may contribute to declining fish stocks. To mediate this problem and maintain fish biomass in aquatic ecosystems, catch-and-release fishing, whereby a fish is caught and immediately released, has been implemented in many countries. It is unclear whether the injuries to the mouth that are caused by the hook have an impact on feeding performance of fishes. Using high-speed video and computational fluid dynamics (CFD), we asked whether injuries around the mouth caused by fishing hooks have a negative impact on suction feeding performance (measured as maximum prey velocity) of the commonly angled marine shiner perch (Cymatogaster aggregata). We hypothesized that fish with mouth injuries would exhibit decreased feeding performance compared with controls. Ten shiner perch were caught using scientific angling and 10 were caught using a seine net. Feeding events were then recorded at 500 frames per second using a high-speed camera. Compared with the control group, maximum prey velocity was significantly lower in the injured group (P<0.01). Maximum gape, time to peak gape, maximum jaw protrusion and predator-prey distance were comparable between the control and injured groups, leading us to conclude that the injury-induced hole in the buccal cavity wall reduced the pressure gradient during mouth expansion, thereby reducing the velocity of water entering the fish's mouth. This was confirmed with our CFD modelling. Fishing injuries in nature are likely to depress feeding performance of fish after they have been released, although it is currently unclear whether this has a significant impact on survival.
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Affiliation(s)
- Melissa Thompson
- Department of Biology, University of Alberta, Edmonton, AB, Canada, T6G 2G7
| | - Sam Van Wassenbergh
- Département Adaptations du Vivant, UMR 7179 CNRS/MNHN, 57 rue Cuvier, Case Postale 55, 75231 Paris Cedex 05, France.,Department of Biology, University of Antwerp, Universiteitsplein 1, 2610 Antwerpen, Belgium
| | - Sean M Rogers
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada, T2N 1N4
| | - Scott G Seamone
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada, T2N 1N4
| | - Timothy E Higham
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, CA 92521, USA
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16
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Arbour J, López-Fernández H. Intrinsic Constraints on the Diversification of Neotropical Cichlid Adductor Mandibulae Size. Anat Rec (Hoboken) 2018; 301:216-226. [DOI: 10.1002/ar.23713] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 07/31/2017] [Accepted: 08/31/2017] [Indexed: 11/11/2022]
Affiliation(s)
- Jessica Arbour
- Department of Ecology and Evolutionary Biology; University of Toronto; 25 Wilcocks Street Toronto, Ontario M5S 3B2 Canada
- Department of Biology; University of Washington; 508 Kincaid, Seattle Washington 98195
| | - Hernán López-Fernández
- Department of Ecology and Evolutionary Biology; University of Toronto; 25 Wilcocks Street Toronto, Ontario M5S 3B2 Canada
- Department of Natural History; Royal Ontario Museum; 100 Queen's Park, Toronto Ontario M5S 2C6 Canada
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17
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Lin M, Mu X, Yan X. The complete mitochondrial genome of Cichla ocellaris. MITOCHONDRIAL DNA PART B-RESOURCES 2017; 2:620-622. [PMID: 33473921 PMCID: PMC7800511 DOI: 10.1080/23802359.2017.1372713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
In this study, the complete mitochondrial (mt) genome of Cichlao cellaris was determined. The mt genome has a length of 16,526 bp and encodes 13 protein-coding genes (PCGs), 22 transfer RNA genes, two ribosomal RNA genes, and one AT-rich non-coding region (D-loop). The gene arrangement was similar to those of typical fishes. The total base composition of the mt genome was 25.1% T, 30.8% C, 29.3% A, and 14.8% G. Of the 13 PCGs, 12 genes start with an ATG codon, except COX1 is with GTG. And among these 13 genes, seven (ND1, COX1, ATP8, ND4L, ND5, ND6, and Cytb) used TAA or TAG as the termination codon, whereas six (ND2, COX2, ATP6, COX3, ND3, and ND4) have incomplete stop codon T. Its control region is atypical in being short at 850 bp. This mt genome sequence data will be useful for phylogenetic and systematic analyses within the family Cichlaidae.
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Affiliation(s)
- Minghui Lin
- Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, China.,Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, China
| | - Xidong Mu
- Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, China
| | - Xi Yan
- Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, China
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18
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Hulsey CD, Zheng J, Faircloth BC, Meyer A, Alfaro ME. Phylogenomic analysis of Lake Malawi cichlid fishes: Further evidence that the three-stage model of diversification does not fit. Mol Phylogenet Evol 2017; 114:40-48. [DOI: 10.1016/j.ympev.2017.05.027] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 05/14/2017] [Accepted: 05/30/2017] [Indexed: 01/05/2023]
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19
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Holzman R, Hulsey CD. Mechanical Transgressive Segregation and the Rapid Origin of Trophic Novelty. Sci Rep 2017; 7:40306. [PMID: 28079133 PMCID: PMC5228120 DOI: 10.1038/srep40306] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 12/05/2016] [Indexed: 01/09/2023] Open
Abstract
Hybrid phenotypes are often intermediate between those of parental species. However, hybridization can generate novel phenotypes when traits are complex. For instance, even when the morphologies of individual musculo-skeletal components do not segregate outside the parental range in hybrid offspring, complex functional systems can exhibit emergent phenotypes whose mechanics exceed the parental values. To determine if transgression in mechanics could facilitate divergence during an adaptive radiation, we examined three functional systems in the trophic apparatus of Lake Malawi cichlid fishes. We conducted a simulation study of hybridization between species pairs whose morphology for three functional systems was empirically measured, to determine how the evolutionary divergence of parental species influences the frequency that hybridization could produce mechanics that transgress the parental range. Our simulations suggest that the complex mechanical systems of the cichlid trophic apparatus commonly exhibit greater transgression between more recently diverged cichlid species. Because (1) all three mechanical systems produce hybrids with transgressive mechanics in Lake Malawi cichlids, (2) hybridization is common, and (3) single hybrid crosses often recapitulate a substantial diversity of mechanics, we conclude that mechanical transgressive segregation could play an important role in the rapid accumulation of phenotypic variation in adaptive radiations.
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Affiliation(s)
- Roi Holzman
- Department of Zoology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
- The Inter-University Institute for Marine Sciences, POB 469, Eilat 88103, Israel
| | - C. Darrin Hulsey
- Department of Biological Sciences, University of Konstanz, Konstanz, 78457, Germany
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20
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Dirt-sifting devilfish: winnowing in the geophagine cichlid Satanoperca daemon and evolutionary implications. ZOOMORPHOLOGY 2016. [DOI: 10.1007/s00435-016-0335-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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21
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Van Wassenbergh S, Potes NZ, Adriaens D. Hydrodynamic drag constrains head enlargement for mouthbrooding in cichlids. J R Soc Interface 2016. [PMID: 26224567 DOI: 10.1098/rsif.2015.0461] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Presumably as an adaptation for mouthbrooding, many cichlid fish species have evolved a prominent sexual dimorphism in the adult head. Since the head of fishes serves as a bow during locomotion, an evolutionary increase in head volume to brood more eggs can trade-off with the hydrodynamic efficiency of swimming. Here, the differences between males and females in three-dimensional shape and size of the external head surfaces and the effect thereof on drag force during locomotion was analysed for the Nile tilapia (Oreochromis niloticus), a maternal mouthbrooder. To do so, three-dimensional body surface reconstructions from laser scans and computational fluid dynamics simulations were performed. After scaling the scanned specimens to post-cranial body volume, in order to theoretically equalize propulsive power, the external volume of the head of females was 27% larger than that of males (head length + 14%; head width + 9%). These differences resulted in an approximate 15% increase in drag force. Yet, hydrodynamics imposed important constraints on the adaptation for mouthbrooding as a much more drastic drop in swimming efficiency seems avoided by mainly enlarging the head along the swimming direction.
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Affiliation(s)
- Sam Van Wassenbergh
- Evolutionary Morphology of Vertebrates, Ghent University, K.L. Ledeganckstraat 35, 9000 Gent, Belgium Department of Biology, Universiteit Antwerpen, Universiteitsplein 1, 2610 Antwerpen, Belgium
| | - Nuno Zavattieri Potes
- Evolutionary Morphology of Vertebrates, Ghent University, K.L. Ledeganckstraat 35, 9000 Gent, Belgium
| | - Dominique Adriaens
- Evolutionary Morphology of Vertebrates, Ghent University, K.L. Ledeganckstraat 35, 9000 Gent, Belgium
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22
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Friedman ST, Price SA, Hoey AS, Wainwright PC. Ecomorphological convergence in planktivorous surgeonfishes. J Evol Biol 2016; 29:965-78. [DOI: 10.1111/jeb.12837] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 01/13/2016] [Accepted: 01/18/2016] [Indexed: 02/04/2023]
Affiliation(s)
- S. T. Friedman
- Department of Evolution and Ecology University of California Davis CA USA
| | - S. A. Price
- Department of Evolution and Ecology University of California Davis CA USA
| | - A. S. Hoey
- ARC Centre of Excellence for Coral Reef Studies James Cook University Townsville Qld Australia
- Red Sea Research Center Division of Biological and Environmental Science and Engineering King Abdullah University of Science and Technology Thuwal Saudi Arabia
| | - P. C. Wainwright
- Department of Evolution and Ecology University of California Davis CA USA
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23
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Gross JB, Stahl BA, Powers AK, Carlson BM. Natural bone fragmentation in the blind cave-dwelling fish, Astyanax mexicanus: candidate gene identification through integrative comparative genomics. Evol Dev 2016; 18:7-18. [PMID: 26153732 PMCID: PMC5226847 DOI: 10.1111/ede.12131] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Animals that colonize dark and nutrient-poor subterranean environments evolve numerous extreme phenotypes. These include dramatic changes to the craniofacial complex, many of which are under genetic control. These phenotypes can demonstrate asymmetric genetic signals wherein a QTL is detected on one side of the face but not the other. The causative gene(s) underlying QTL are difficult to identify with limited genomic resources. We approached this task by searching for candidate genes mediating fragmentation of the third suborbital bone (SO3) directly inferior to the orbit of the eye. We integrated positional genomic information using emerging Astyanax resources, and linked these intervals to homologous (syntenic) regions of the Danio rerio genome. We identified a discrete, approximately 6 Mb, conserved region wherein the gene causing SO3 fragmentation likely resides. We interrogated this interval for genes demonstrating significant differential expression using mRNA-seq analysis of cave and surface morphs across life history. We then assessed genes with known roles in craniofacial evolution and development based on GO term annotation. Finally, we screened coding sequence alterations in this region, identifying two key genes: transforming growth factor β3 (tgfb3) and bone morphogenetic protein 4 (bmp4). Of these candidates, tgfb3 is most promising as it demonstrates significant differential expression across multiple stages of development, maps close (<1 Mb) to the fragmentation critical locus, and is implicated in a variety of other animal systems (including humans) in non-syndromic clefting and malformations of the cranial sutures. Both abnormalities are analogous to the failure-to-fuse phenotype that we observe in SO3 fragmentation. This integrative approach will enable discovery of the causative genetic lesions leading to complex craniofacial features analogous to human craniofacial disorders. This work underscores the value of cave-dwelling fish as a powerful evolutionary model of craniofacial disease, and demonstrates the power of integrative system-level studies for informing the genetic basis of craniofacial aberrations in nature.
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Affiliation(s)
- Joshua B. Gross
- Department of Biological Sciences, University of Cincinnati, 312 Clifton Court, Cincinnati, Ohio 45221, USA
| | - Bethany A. Stahl
- Department of Biological Sciences, University of Cincinnati, 312 Clifton Court, Cincinnati, Ohio 45221, USA
| | - Amanda K. Powers
- Department of Biological Sciences, University of Cincinnati, 312 Clifton Court, Cincinnati, Ohio 45221, USA
| | - Brian M. Carlson
- Department of Biological Sciences, University of Cincinnati, 312 Clifton Court, Cincinnati, Ohio 45221, USA
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24
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Ferguson AR, Huber DR, Lajeunesse MJ, Motta PJ. Feeding performance of king Mackerel, Scomberomorus cavalla. ACTA ACUST UNITED AC 2015; 323:399-413. [PMID: 25845956 DOI: 10.1002/jez.1933] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 03/05/2015] [Accepted: 03/06/2015] [Indexed: 11/09/2022]
Abstract
Feeding performance is an organism's ability to capture and handle prey. Although bite force is a commonly used metric of feeding performance, other factors such as bite pressure and strike speed are also likely to affect prey capture. Therefore, this study investigated static bite force, dynamic speeds, and predator and prey forces resulting from ram strikes, as well as bite pressure of the king mackerel, Scomberomorus cavalla, in order to examine their relative contributions to overall feeding performance. Theoretical posterior bite force ranged from 14.0-318.7 N. Ram speed, recorded with a rod and reel incorporated with a line counter and video camera, ranged from 3.3-15.8B L/s. Impact forces on the prey ranged from 0.1-1.9 N. Bite pressure, estimated using theoretical bite forces at three gape angles and tooth cross-sectional areas, ranged from 1.7-56.9 MPa. Mass-specific bite force for king mackerel is relatively low in comparison with other bony fishes and sharks, with relatively little impact force applied to the prey during the strike. This suggests that king mackerel rely on high velocity chases and high bite pressure generated via sharp, laterally compressed teeth to maximize feeding performance.
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Affiliation(s)
- Amber R Ferguson
- Department of Integrative Biology, University of South Florida, Tampa, Florida
| | - Daniel R Huber
- Department of Biology, University of Tampa, Tampa, Florida
| | - Marc J Lajeunesse
- Department of Integrative Biology, University of South Florida, Tampa, Florida
| | - Philip J Motta
- Department of Integrative Biology, University of South Florida, Tampa, Florida
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25
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Mara KR, Motta PJ, Martin AP, Hueter RE. Constructional morphology within the head of hammerhead sharks (sphyrnidae). J Morphol 2015; 276:526-39. [PMID: 25684106 DOI: 10.1002/jmor.20362] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 11/24/2014] [Accepted: 12/02/2014] [Indexed: 01/11/2023]
Abstract
The study of functional trade-offs is important if a structure, such as the cranium, serves multiple biological roles, and is, therefore, shaped by multiple selective pressures. The sphyrnid cephalofoil presents an excellent model for investigating potential trade-offs among sensory, neural, and feeding structures. In this study, hammerhead shark species were chosen to represent differences in head form through phylogeny. A combination of surface-based geometric morphometrics, computed tomography (CT) volumetric analysis, and phylogenetic analyses were utilized to investigate potential trade-offs within the head. Hammerhead sharks display a diversity of cranial morphologies where the position of the eyes and nares vary among species, with only minor changes in shape, position, and volume of the feeding apparatus through phylogeny. The basal winghead shark, Eusphyra blochii, has small anteriorly positioned eyes. Through phylogeny, the relative size and position of the eyes change, such that derived species have larger, more medially positioned eyes. The lateral position of the external nares is highly variable, showing no phylogenetic trend. Mouth size and position are conserved, remaining relatively unchanged. Volumetric CT analyses reveal no trade-offs between the feeding apparatus and the remaining cranial structures. The few trade-offs were isolated to the nasal capsule volume's inverse correlation with braincase, chondrocranial, and total cephalofoil volume. Eye volume also decreased as cephalofoil width increased. These data indicate that despite considerable changes in head shape, much of the head is morphologically conserved through sphyrnid phylogeny, particularly the jaw cartilages and their associated feeding muscles, with shape change and morphological trade-offs being primarily confined to the lateral wings of the cephalofoil and their associated sensory structures.
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Affiliation(s)
- Kyle R Mara
- Department of Integrative Biology, University of South Florida, Tampa, Florida, 33620
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26
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Interrelationships Between Bones, Muscles, and Performance: Biting in the Lizard Tupinambis merianae. Evol Biol 2014. [DOI: 10.1007/s11692-014-9286-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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27
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Mu XD, Liu C, Wang XJ, Liu Y, Hu YC, Luo JR. Complete mitochondrial genome of Zebra tilapia, Tilapia buttikoferi. Mitochondrial DNA A DNA Mapp Seq Anal 2014; 27:44-5. [PMID: 24438265 DOI: 10.3109/19401736.2013.869687] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
We determined the complete mitochondrial genome of Tilapia buttikoferi, which was 16,577 bp in length with an A + T content of 53.0%, containing 13 protein-coding genes, 2 rRNAs, 22 tRNAs and a complete control region. The gene arrangement was similar to that of typical fishes. The total base composition of the mitogenome was 25.6% T, 30.8% C, 27.4% A and 16.2% G. Of the 13 protein-coding genes, 12 genes start with an ATG codon, except for COX1 with GTG. Seven (ND1, ND2, COX1, ATPase8, ATPase6, ND4L and ND6) used TAA or AGA as the termination codon, whereas six (COX2, COX3, ND3, ND4, ND5 and cyt b) had incomplete stop codon T. Its control region was atypical in being short at 861 bp, and contained TACAT motif and one microsatellite-like region (TA)7. This mitogenome sequence data may be useful for phylogenetic and systematic analyses within the family Cichlaidae.
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Affiliation(s)
- Xi-Dong Mu
- a Key Laboratory of Tropical & Subtropical Fishery Resource Application & Cultivation , Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Ministry of Agriculture , Guangzhou , China
| | - Chao Liu
- a Key Laboratory of Tropical & Subtropical Fishery Resource Application & Cultivation , Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Ministry of Agriculture , Guangzhou , China
| | - Xue-Jie Wang
- a Key Laboratory of Tropical & Subtropical Fishery Resource Application & Cultivation , Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Ministry of Agriculture , Guangzhou , China
| | - Yi Liu
- a Key Laboratory of Tropical & Subtropical Fishery Resource Application & Cultivation , Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Ministry of Agriculture , Guangzhou , China
| | - Yin-Chang Hu
- a Key Laboratory of Tropical & Subtropical Fishery Resource Application & Cultivation , Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Ministry of Agriculture , Guangzhou , China
| | - Jian-Ren Luo
- a Key Laboratory of Tropical & Subtropical Fishery Resource Application & Cultivation , Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Ministry of Agriculture , Guangzhou , China
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28
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Rupp MF, Hulsey CD. Influence of substrate orientation on feeding kinematics and performance of algae grazing Lake Malawi cichlid fishes. J Exp Biol 2014; 217:3057-66. [DOI: 10.1242/jeb.105080] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
Lake Malawi cichlids have been studied extensively in an effort to elucidate the mechanisms underlying their adaptive radiation. Both habitat partitioning and trophic specialization have been suggested to be critical ecological axes underlying the exceptional diversification of these fishes, but the mechanisms facilitating this divergence are often unclear. For instance, in the rock-dwelling mbuna of Lake Malawi, coexistence is likely tightly linked to how and where species feed on the algae coating all the surfaces of the rocky reefs they exclusively inhabit. Yet, although mbuna species often preferentially graze from particular substrate orientations, we understand very little about how substrate orientation influences feeding kinematics or feeding rates in any group of organisms. Therefore, for three species of mbuna, we quantified feeding kinematics and inferred the rates that algae could be ingested on substrates that mimicked the top, sides, and bottoms of the algae covered boulders these species utilize in Lake Malawi. A number of differences in feeding kinematics were found among species, and several of the kinematic variables were found to differ even within species when the fish grazed from different surface orientations. However, despite their preferences for particular microhabitats, we found no evidence for clear tradeoffs in the rates that the three species were inferred to be able to obtain algae from different substrate orientations. Nevertheless, our results indicate microhabitat divergence linked to differences in feeding kinematics could have played a role in the origin and maintenance of the vast diversity of co-occurring Lake Malawi mbuna species.
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29
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Joo D, Kwan YS, Song J, Pinho C, Hey J, Won YJ. Identification of cichlid fishes from Lake Malawi using computer vision. PLoS One 2013; 8:e77686. [PMID: 24204918 PMCID: PMC3808401 DOI: 10.1371/journal.pone.0077686] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Accepted: 09/03/2013] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND The explosively radiating evolution of cichlid fishes of Lake Malawi has yielded an amazing number of haplochromine species estimated as many as 500 to 800 with a surprising degree of diversity not only in color and stripe pattern but also in the shape of jaw and body among them. As these morphological diversities have been a central subject of adaptive speciation and taxonomic classification, such high diversity could serve as a foundation for automation of species identification of cichlids. METHODOLOGY/PRINCIPAL FINDING Here we demonstrate a method for automatic classification of the Lake Malawi cichlids based on computer vision and geometric morphometrics. For this end we developed a pipeline that integrates multiple image processing tools to automatically extract informative features of color and stripe patterns from a large set of photographic images of wild cichlids. The extracted information was evaluated by statistical classifiers Support Vector Machine and Random Forests. Both classifiers performed better when body shape information was added to the feature of color and stripe. Besides the coloration and stripe pattern, body shape variables boosted the accuracy of classification by about 10%. The programs were able to classify 594 live cichlid individuals belonging to 12 different classes (species and sexes) with an average accuracy of 78%, contrasting to a mere 42% success rate by human eyes. The variables that contributed most to the accuracy were body height and the hue of the most frequent color. CONCLUSIONS Computer vision showed a notable performance in extracting information from the color and stripe patterns of Lake Malawi cichlids although the information was not enough for errorless species identification. Our results indicate that there appears an unavoidable difficulty in automatic species identification of cichlid fishes, which may arise from short divergence times and gene flow between closely related species.
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Affiliation(s)
- Deokjin Joo
- Department of Electrical Engineering and Computer Science, Seoul National University, Seoul, Korea
| | - Ye-seul Kwan
- Division of EcoScience, Ewha Womans University, Seoul, Korea
| | - Jongwoo Song
- Department of Statistics, Ewha Womans University, Seoul, Korea
| | - Catarina Pinho
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Vairão, Portugal
| | - Jody Hey
- Department of Biology, Temple University, Philadelphia, Pennsylvania, United States of America
| | - Yong-Jin Won
- Division of EcoScience, Ewha Womans University, Seoul, Korea
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30
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Hulsey CD, Roberts RJ, Loh YHE, Rupp MF, Streelman JT. Lake Malawi cichlid evolution along a benthic/limnetic axis. Ecol Evol 2013; 3:2262-72. [PMID: 23919168 PMCID: PMC3728963 DOI: 10.1002/ece3.633] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Revised: 05/08/2013] [Accepted: 05/09/2013] [Indexed: 11/12/2022] Open
Abstract
Divergence along a benthic to limnetic habitat axis is ubiquitous in aquatic systems. However, this type of habitat divergence has largely been examined in low diversity, high latitude lake systems. In this study, we examined the importance of benthic and limnetic divergence within the incredibly species-rich radiation of Lake Malawi cichlid fishes. Using novel phylogenetic reconstructions, we provided a series of hypotheses regarding the evolutionary relationships among 24 benthic and limnetic species that suggests divergence along this axis has occurred multiple times within Lake Malawi cichlids. Because pectoral fin morphology is often associated with divergence along this habitat axis in other fish groups, we investigated divergence in pectoral fin muscles in these benthic and limnetic cichlid species. We showed that the eight pectoral fin muscles and fin area generally tended to evolve in a tightly correlated manner in the Lake Malawi cichlids. Additionally, we found that larger pectoral fin muscles are strongly associated with the independent evolution of the benthic feeding habit across this group of fish. Evolutionary specialization along a benthic/limnetic axis has occurred multiple times within this tropical lake radiation and has produced repeated convergent matching between exploitation of water column habitats and locomotory morphology.
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Affiliation(s)
- C D Hulsey
- Department of Ecology and Evolutionary Biology, University of Tennessee Knoxville, Tennessee, 37996
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Darrin Hulsey C, Keck BP, Alamillo H, O'Meara BC. Mitochondrial genome primers for Lake Malawi cichlids. Mol Ecol Resour 2013; 13:347-53. [PMID: 23347464 DOI: 10.1111/1755-0998.12066] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Revised: 12/11/2012] [Accepted: 12/12/2012] [Indexed: 11/28/2022]
Abstract
Resolving the evolutionary history of rapidly diversifying lineages like the Lake Malawi Cichlid Flock demands powerful phylogenetic tools. Although this clade of over 500 species of fish likely diversified in less than two million years, the availability of extensive sequence data sets, such as complete mitochondrial genomes, could help resolve evolutionary patterns in this group. Using a large number of newly developed primers, we generated whole mitochondrial genome sequences for 14 Lake Malawi cichlids. We compared sequence divergence across protein-coding regions of the mitochondrial genome and also compared divergence in the mitochondrial loci to divergence at two nuclear protein-coding loci, Mitfb and Dlx2. Despite the widespread sharing of haplotypes of identical sequences at individual loci, the combined use of all protein-coding mitochondrial loci provided a bifurcating phylogenetic hypothesis for the exemplars of major lineages within the Lake Malawi cichlid radiation. The primers presented here could have substantial utility for evolutionary analyses of mitochondrial evolution and hybridization within this diverse clade.
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Affiliation(s)
- C Darrin Hulsey
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN 37996, USA.
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Tkint T, Verheyen E, De Kegel B, Helsen P, Adriaens D. Dealing with food and eggs in mouthbrooding cichlids: structural and functional trade-offs in fitness related traits. PLoS One 2012; 7:e31117. [PMID: 22348043 PMCID: PMC3279513 DOI: 10.1371/journal.pone.0031117] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Accepted: 01/03/2012] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND As in any vertebrate, heads of fishes are densely packed with functions. These functions often impose conflicting mechanical demands resulting in trade-offs in the species-specific phenotype. When phenotypical traits are linked to gender-specific parental behavior, we expect sexual differences in these trade-offs. This study aims to use mouthbrooding cichlids as an example to test hypotheses on evolutionary trade-offs between intricately linked traits that affect different aspects of fitness. We focused on the oral apparatus, which is not only equipped with features used to feed and breathe, but is also used for the incubation of eggs. We used this approach to study mouthbrooding as part of an integrated functional system with diverging performance requirements and to explore gender-specific selective environments within a species. METHODOLOGY/PRINCIPAL FINDINGS Because cichlids are morphologically very diverse, we hypothesize that the implications of the added constraint of mouthbrooding will primarily depend on the dominant mode of feeding of the studied species. To test this, we compared the trade-off for two maternal mouthbrooding cichlid species: a "suction feeder" (Haplochromis piceatus) and a "biter" (H. fischeri). The comparison of morphology and performance of both species revealed clear interspecific and intersex differences. Our observation that females have larger heads was interpreted as a possible consequence of the fact that in both the studied species mouthbrooding is done by females only. As hypothesized, the observed sexual dimorphism in head shape is inferred as being suboptimal for some aspects of the feeding performance in each of the studied species. Our comparison also demonstrated that the suction feeding species had smaller egg clutches and more elongated eggs. CONCLUSIONS/SIGNIFICANCE Our findings support the hypothesis that there is a trade-off between mouthbrooding and feeding performance in the two studied haplochromine cichlids, stressing the importance of including species-specific information at the gender level when addressing interspecific functional/morphological differences.
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Affiliation(s)
- Tim Tkint
- Department of Biology, Research Group Evolutionary Morphology of Vertebrates, Ghent University, Ghent, Belgium.
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HULSEY CDARRIN, HOLLINGSWORTH JR PHILLIPR. Do constructional constraints influence cyprinid (Cyprinidae: Leuciscinae) craniofacial coevolution? Biol J Linn Soc Lond 2011. [DOI: 10.1111/j.1095-8312.2011.01628.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Berner D. Size correction in biology: how reliable are approaches based on (common) principal component analysis? Oecologia 2011; 166:961-71. [DOI: 10.1007/s00442-011-1934-z] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Accepted: 02/01/2011] [Indexed: 11/28/2022]
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Abstract
A long-standing debate in ecology addresses whether community composition is the result of stochastic factors or assembly rules. Non-random, over-dispersed patterns of species co-occurrence have commonly been attributed to competition--a particularly important force in adaptive radiation. We thus examined the macroecology of the recently radiated cichlid rock-fish assemblage in Lake Malawi, Africa at a spectrum of increasingly fine spatial scales (entire lake to depth within rock-reef sites). Along this range of spatial scales, we observed a signal of community structure (decreased co-occurrence of species) at the largest and smallest scales, but not in between. Evidence suggests that the lakewide signature of structure is driven by extreme endemism and micro-allopatric speciation, while patterns of reduced co-occurrence with depth are indicative of species interactions. We identified a 'core' set of rock-reef species, found in combination throughout the lake, whose depth profiles exhibited replicated positive and negative correlation. Our results provide insight into how ecological communities may be structured differently at distinct spatial scales, re-emphasize the importance of local species interactions in community assembly, and further elucidate the processes shaping speciation in this model adaptive radiation.
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Affiliation(s)
- Nicholas F Parnell
- Department of Biology, Georgia Institute of Technology, Atlanta, GA 30332, USA.
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Willacker JJ, von Hippel FA, Wilton PR, Walton KM. Classification of threespine stickleback along the benthic-limnetic axis. Biol J Linn Soc Lond 2010; 101:595-608. [PMID: 21221422 DOI: 10.1111/j.1095-8312.2010.01531.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Many species of fish display morphological divergence between individuals feeding on macroinvertebrates associated with littoral habitats (benthic morphotypes) and individuals feeding on zooplankton in the limnetic zone (limnetic morphotypes). Threespine stickleback (Gasterosteus aculeatus L.) have diverged along the benthic-limnetic axis into allopatric morphotypes in thousands of populations and into sympatric species pairs in several lakes. However, only a few well known populations have been studied because identifying additional populations as either benthic or limnetic requires detailed dietary or observational studies. Here we develop a Fisher's linear discriminant function based on the skull morphology of known benthic and limnetic stickleback populations from the Cook Inlet Basin of Alaska and test the feasibility of using this function to identify other morphologically divergent populations. Benthic and limnetic morphotypes were separable using this technique and of 45 populations classified, three were identified as morphologically extreme (two benthic and one limnetic), nine as moderately divergent (three benthic and six limnetic) and the remaining 33 populations as morphologically intermediate. Classification scores were found to correlate with eye size, the depth profile of lakes, and the presence of invasive northern pike (Esox lucius). This type of classification function provides a means of integrating the complex morphological differences between morphotypes into a single score that reflects the position of a population along the benthic-limnetic axis and can be used to relate that position to other aspects of stickleback biology.
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Affiliation(s)
- James J Willacker
- Department of Biological Sciences, University of Alaska Anchorage, 3211 Providence Dr., Anchorage AK 99508, USA
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Hellig CJ, Kerschbaumer M, Sefc KM, Koblmüller S. Allometric shape change of the lower pharyngeal jaw correlates with a dietary shift to piscivory in a cichlid fish. THE SCIENCE OF NATURE - NATURWISSENSCHAFTEN 2010; 97:663-72. [PMID: 20532473 DOI: 10.1007/s00114-010-0682-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2010] [Revised: 05/18/2010] [Accepted: 05/19/2010] [Indexed: 11/29/2022]
Abstract
The morphological versatility of the pharyngeal jaw of cichlid fishes is assumed to represent a key factor facilitating their unparalleled trophic diversification and explosive radiation. It is generally believed that the functional design of an organism relates to its ecology, and thus, specializations to different diets are typically associated with distinct morphological designs, especially manifested in the cichlids' pharyngeal jaw apparatus. Thereby, the lower pharyngeal jaw (LPJ) incorporates some of the most predictive features for distinct diet-related morphotypes. Thus, considering that piscivorous cichlids experience an ontogenetic dietary shift from typically various kinds of invertebrates to fish, concomitant morphological changes in the LPJ are expected. Using Lepidiolamprologus elongatus, a top predator in the shallow rocky habitat of Lake Tanganyika, as model, and applying geometric and traditional morphometric techniques, we demonstrate an allometric change in ontogenetic LPJ shape development coinciding with the completion of the dietary shift toward piscivory. The piscivorous LPJ morphotype is initiated in juvenile fish by increasing elongation and narrowing of the LPJ and--when the fish reach a size of 80-90 mm standard length--further refined by the elongation of the posterior muscular processes, which serve as insertion for the fourth musculus levator externus. The enlarged muscular processes of the fully mature piscivorous morphotype provide for the construction of a powerful lever system, which allows the large individuals to process large prey fish and rely on exclusive piscivory.
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Affiliation(s)
- Christoph J Hellig
- Department of Zoology, Karl-Franzens-University Graz, Universitätsplatz 2, 8010, Graz, Austria
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Hulsey CD, Mims MC, Parnell NF, Streelman JT. Comparative rates of lower jaw diversification in cichlid adaptive radiations. J Evol Biol 2010; 23:1456-67. [PMID: 20456574 DOI: 10.1111/j.1420-9101.2010.02004.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The lower jaw (LJ) provides an ideal trophic phenotype to compare rates and patterns of macroevolution among cichlid radiations. Using a novel phylogeny of four genes (ND2, dlx2, mitfb, and s7), we examined the evolutionary relationships among two of the most phylogenetically disparate cichlid radiations: (i) the Central America Heroines; and (ii) the East African Lake Malawi flock. To quantify jaw morphology, we measured two LJ lever systems in approximately 40 species from each lineage. Using geologic calibrations, we generated a chronogram for both groups and examined the rates of jaw evolution in the two radiations. The most rapidly evolving components of the LJ differed between the two radiations. However, the Lake Malawi flock exhibited a much faster rate of evolution in several components of the LJ. This rapid rate of divergence is consistent with natural selection, promoting unparalleled trophic diversification in Lake Malawi cichlids.
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Affiliation(s)
- C D Hulsey
- Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN 37996, USA.
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Abstract
Differences in brain region size among species are thought to arise late in development via adaptive control over neurogenesis, as cells of previously patterned compartments proliferate, die, and/or differentiate into neurons. Here we investigate comparative brain development in ecologically distinct cichlid fishes from Lake Malawi and demonstrate that brains vary among recently evolved lineages because of early patterning. Divergence among rock-dwellers and sand-dwellers in the relative size of the telencephalon versus the thalamus is correlated with gene expression variation in a regulatory circuit (composed of six3, fezf2, shh, irx1b, and wnt1) known from model organisms to specify anterior-posterior (AP) brain polarity and position the shh-positive signaling boundary zona limitans intrathalamica (ZLI) in the forebrain. To confirm that changes in this coexpression network are sufficient to produce the differences we observe, we manipulated WNT signaling in vivo by treating rock-dwelling cichlid embryos with temporally precise doses of LiCl. Chemically treated rock-dwellers develop gene expression patterns, ZLIs, and forebrains distinct from controls and untreated conspecifics, but strongly resembling those of sand-dwellers. Notably, endemic Malawi rock- and sand-dwelling lineages are alternately fixed for an SNP in irx1b, a mediator of WNT signaling required for proper thalamus and ZLI. Together, these natural experiments in neuroanatomy, development, and genomics suggest that evolutionary changes in AP patterning establish ecologically relevant differences in the elaboration of cichlid forebrain compartments. In general, variation in developmental patterning might lay the foundations on which neurogenesis erects diverse brain architectures.
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MIMS MERYLC, DARRIN HULSEY C, FITZPATRICK BENJAMINM, TODD STREELMAN J. Geography disentangles introgression from ancestral polymorphism in Lake Malawi cichlids. Mol Ecol 2010; 19:940-51. [DOI: 10.1111/j.1365-294x.2010.04529.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Revell LJ. Size-correction and principal components for interspecific comparative studies. Evolution 2009; 63:3258-68. [PMID: 19663993 DOI: 10.1111/j.1558-5646.2009.00804.x] [Citation(s) in RCA: 538] [Impact Index Per Article: 35.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Phylogenetic methods for the analysis of species data are widely used in evolutionary studies. However, preliminary data transformations and data reduction procedures (such as a size-correction and principal components analysis, PCA) are often performed without first correcting for nonindependence among the observations for species. In the present short comment and attached R and MATLAB code, I provide an overview of statistically correct procedures for phylogenetic size-correction and PCA. I also show that ignoring phylogeny in preliminary transformations can result in significantly elevated variance and type I error in our statistical estimators, even if subsequent analysis of the transformed data is performed using phylogenetic methods. This means that ignoring phylogeny during preliminary data transformations can possibly lead to spurious results in phylogenetic statistical analyses of species data.
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Affiliation(s)
- Liam J Revell
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
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Hulsey CD. Cichlid genomics and phenotypic diversity in a comparative context. Integr Comp Biol 2009; 49:618-29. [DOI: 10.1093/icb/icp071] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Fraser GJ, Hulsey CD, Bloomquist RF, Uyesugi K, Manley NR, Streelman JT. An ancient gene network is co-opted for teeth on old and new jaws. PLoS Biol 2009; 7:e31. [PMID: 19215146 PMCID: PMC2637924 DOI: 10.1371/journal.pbio.1000031] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2008] [Accepted: 01/05/2009] [Indexed: 11/18/2022] Open
Abstract
Vertebrate dentitions originated in the posterior pharynx of jawless fishes more than half a billion years ago. As gnathostomes (jawed vertebrates) evolved, teeth developed on oral jaws and helped to establish the dominance of this lineage on land and in the sea. The advent of oral jaws was facilitated, in part, by absence of hox gene expression in the first, most anterior, pharyngeal arch. Much later in evolutionary time, teleost fishes evolved a novel toothed jaw in the pharynx, the location of the first vertebrate teeth. To examine the evolutionary modularity of dentitions, we asked whether oral and pharyngeal teeth develop using common or independent gene regulatory pathways. First, we showed that tooth number is correlated on oral and pharyngeal jaws across species of cichlid fishes from Lake Malawi (East Africa), suggestive of common regulatory mechanisms for tooth initiation. Surprisingly, we found that cichlid pharyngeal dentitions develop in a region of dense hox gene expression. Thus, regulation of tooth number is conserved, despite distinct developmental environments of oral and pharyngeal jaws; pharyngeal jaws occupy hox-positive, endodermal sites, and oral jaws develop in hox-negative regions with ectodermal cell contributions. Next, we studied the expression of a dental gene network for tooth initiation, most genes of which are similarly deployed across the two disparate jaw sites. This collection of genes includes members of the ectodysplasin pathway, eda and edar, expressed identically during the patterning of oral and pharyngeal teeth. Taken together, these data suggest that pharyngeal teeth of jawless vertebrates utilized an ancient gene network before the origin of oral jaws, oral teeth, and ectodermal appendages. The first vertebrate dentition likely appeared in a hox-positive, endodermal environment and expressed a genetic program including ectodysplasin pathway genes. This ancient regulatory circuit was co-opted and modified for teeth in oral jaws of the first jawed vertebrate, and subsequently deployed as jaws enveloped teeth on novel pharyngeal jaws. Our data highlight an amazing modularity of jaws and teeth as they coevolved during the history of vertebrates. We exploit this diversity to infer a core dental gene network, common to the first tooth and all of its descendants.
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Affiliation(s)
- Gareth J Fraser
- Parker H. Petit Institute for Bioengineering and Biosciences and School of Biology, Georgia Institute of Technology, Atlanta, Georgia, United States of America
- * To whom correspondence should be addressed. E-mail: (GJF); (JTS)
| | - C. Darrin Hulsey
- Parker H. Petit Institute for Bioengineering and Biosciences and School of Biology, Georgia Institute of Technology, Atlanta, Georgia, United States of America
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, Tennessee, United States of America
| | - Ryan F Bloomquist
- Parker H. Petit Institute for Bioengineering and Biosciences and School of Biology, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Kristine Uyesugi
- Parker H. Petit Institute for Bioengineering and Biosciences and School of Biology, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Nancy R Manley
- Department of Genetics, University of Georgia, Athens, Georgia, United States of America
| | - J. Todd Streelman
- Parker H. Petit Institute for Bioengineering and Biosciences and School of Biology, Georgia Institute of Technology, Atlanta, Georgia, United States of America
- * To whom correspondence should be addressed. E-mail: (GJF); (JTS)
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Cooper WJ, Westneat MW. Form and function of damselfish skulls: rapid and repeated evolution into a limited number of trophic niches. BMC Evol Biol 2009; 9:24. [PMID: 19183467 PMCID: PMC2654721 DOI: 10.1186/1471-2148-9-24] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2008] [Accepted: 01/30/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Damselfishes (Perciformes, Pomacentridae) are a major component of coral reef communities, and the functional diversity of their trophic anatomy is an important constituent of the ecological morphology of these systems. Using shape analyses, biomechanical modelling, and phylogenetically based comparative methods, we examined the anatomy of damselfish feeding among all genera and trophic groups. Coordinate based shape analyses of anatomical landmarks were used to describe patterns of morphological diversity and determine positions of functional groups in a skull morphospace. These landmarks define the lever and linkage structures of the damselfish feeding system, and biomechanical analyses of this data were performed using the software program JawsModel4 in order to calculate the simple mechanical advantage (MA) employed by different skull elements during feeding, and to compute kinematic transmission coefficients (KT) that describe the efficiency with which angular motion is transferred through the complex linkages of damselfish skulls. RESULTS Our results indicate that pomacentrid planktivores are significantly different from other damselfishes, that biting MA values and protrusion KT ratios are correlated with pomacentrid trophic groups more tightly than KT scores associated with maxillary rotation and gape angle, and that the MAs employed by their three biting muscles have evolved independently. Most of the biomechanical parameters examined have experienced low levels of phylogenetic constraint, which suggests that they have evolved quickly. CONCLUSION Joint morphological and biomechanical analyses of the same anatomical data provided two reciprocally illuminating arrays of information. Both analyses showed that the evolution of planktivory has involved important changes in pomacentrid functional morphology, and that the mechanics of upper jaw kinesis have been of great importance to the evolution of damselfish feeding. Our data support a tight and biomechanically defined link between structure and the functional ecology of fish skulls, and indicate that certain mechanisms for transmitting motion through their jaw linkages may require particular anatomical configurations, a conclusion that contravenes the concept of "many-to-one mapping" for fish jaw mechanics. Damselfish trophic evolution is characterized by rapid and repeated shifts between a small number of eco-morphological states, an evolutionary pattern that we describe as reticulate adaptive radiation.
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Affiliation(s)
- W James Cooper
- Department of Organismal Biology & Anatomy, University of Chicago, Chicago, IL 60637, USA
- Department of Zoology, Field Museum of Natural History, Chicago, IL 60605, USA
- Department of Biology, Syracuse University, Syracuse, NY 13244, USA
| | - Mark W Westneat
- Department of Organismal Biology & Anatomy, University of Chicago, Chicago, IL 60637, USA
- Department of Zoology, Field Museum of Natural History, Chicago, IL 60605, USA
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Kuraku S, Meyer A. Genomic analysis of cichlid fish 'natural mutants'. Curr Opin Genet Dev 2008; 18:551-8. [PMID: 19095433 DOI: 10.1016/j.gde.2008.11.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2008] [Accepted: 11/03/2008] [Indexed: 11/24/2022]
Abstract
In the lakes of East Africa, cichlid fishes have formed adaptive radiations that are each composed of hundreds of endemic, morphologically stunningly diverse, but genetically extremely similar species. In the past 20 years, it became clear that their extreme phenotypic diversity arose within very short time spans, and that phenotypically radically different species are exceptionally similar genetically; hence, they could be considered to be 'natural mutants'. Many species can be hybridized and, therefore, provide a unique opportunity to study the genetic underpinnings of phenotypic diversification. Comparative large-scale genomic analyses are beginning to unravel the patterns and processes that led to the formation of the cichlid species flocks. Cichlids are an emerging evolutionary genomic model system for fundamental questions on the origin of phenotypic diversity.
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Affiliation(s)
- Shigehiro Kuraku
- Lehrstuhl für Zoologie und Evolutionsbiologie, Department of Biology, University of Konstanz, Konstanz, Germany
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Loh YHE, Katz LS, Mims MC, Kocher TD, Yi SV, Streelman JT. Comparative analysis reveals signatures of differentiation amid genomic polymorphism in Lake Malawi cichlids. Genome Biol 2008; 9:R113. [PMID: 18616806 PMCID: PMC2530870 DOI: 10.1186/gb-2008-9-7-r113] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2008] [Revised: 06/19/2008] [Accepted: 07/10/2008] [Indexed: 11/25/2022] Open
Abstract
Low coverage survey sequencing shows that although Lake Malawi cichlids are phenotypically and behaviorally diverse, they appear genetically like a subdivided population. Background Cichlid fish from East Africa are remarkable for phenotypic and behavioral diversity on a backdrop of genomic similarity. In 2006, the Joint Genome Institute completed low coverage survey sequencing of the genomes of five phenotypically and ecologically diverse Lake Malawi species. We report a computational and comparative analysis of these data that provides insight into the mechanisms that make closely related species different from one another. Results We produced assemblies for the five species ranging in aggregate length from 68 to 79 megabase pairs, identified putative orthologs for more than 12,000 human genes, and predicted more than 32,000 cross-species single nucleotide polymorphisms (SNPs). Nucleotide diversity was lower than that found among laboratory strains of the zebrafish. We collected around 36,000 genotypes to validate a subset of SNPs within and among populations and across multiple individuals of about 75 Lake Malawi species. Notably, there were no fixed differences observed between focal species nor between major lineages. Roughly 3% to 5% of loci surveyed are statistical outliers for genetic differentiation (FST) within species, between species, and between major lineages. Outliers for FST are candidate genes that may have experienced a history of natural selection in the Malawi lineage. Conclusion We present a novel genome sequencing strategy, which is useful when evolutionary diversity is the question of interest. Lake Malawi cichlids are phenotypically and behaviorally diverse, but they appear genetically like a subdivided population. The unique structure of Lake Malawl cichlid genomes should facilitate conceptually new experiments, employing SNPs to identity genotype-phenotype association, using the entire species flock as a mapping panel.
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Affiliation(s)
- Yong-Hwee E Loh
- School of Biology, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, 315 Ferst Drive, Atlanta, Georgia 30332, USA.
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Parnell NF, Hulsey CD, Streelman JT. Hybridization produces novelty when the mapping of form to function is many to one. BMC Evol Biol 2008; 8:122. [PMID: 18442407 PMCID: PMC2386449 DOI: 10.1186/1471-2148-8-122] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2008] [Accepted: 04/28/2008] [Indexed: 11/10/2022] Open
Abstract
Background Evolutionary biologists want to explain the origin of novel features and functions. Two recent but separate lines of research address this question. The first describes one possible outcome of hybridization, called transgressive segregation, where hybrid offspring exhibit trait distributions outside of the parental range. The second considers the explicit mapping of form to function and illustrates manifold paths to similar function (called many to one mapping, MTOM) when the relationship between the two is complex. Under this scenario, functional novelty may be a product of the number of ways to elicit a functional outcome (i.e., the degree of MTOM). We fuse these research themes by considering the influence of MTOM on the production of transgressive jaw biomechanics in simulated hybrids between Lake Malawi cichlid species. Results We characterized the component links and functional output (kinematic transmission, KT) of the 4-bar mechanism in the oral jaws of Lake Malawi cichlids. We demonstrated that the input and output links, the length of the lower jaw and the length of the maxilla respectively, have consistent but opposing relationships with KT. Based on these data, we predicted scenarios in which species with different morphologies but similar KT (MTOM species) would produce transgressive function in hybrids. We used a simple but realistic genetic model to show that transgressive function is a likely outcome of hybridization among Malawi species exhibiting MTOM. Notably, F2 hybrids are transgressive for function (KT), but not the component links that contribute to function. In our model, transgression is a consequence of recombination and assortment among alleles specifying the lengths of the lower jaw and maxilla. Conclusion We have described a general and likely pervasive mechanism that generates functional novelty. Simulations of hybrid offspring among Lake Malawi cichlids exhibiting MTOM produce transgressive function in the majority of cases, and at appreciable frequency. Functional transgression (i) is a product of recombination and assortment between alleles controlling the lengths of the lower jaw and the maxilla, (ii) occurs in the absence of transgressive morphology, and (iii) can be predicted from the morphology of parents. Our genetic model can be tested by breeding Malawi cichlid hybrids in the laboratory and examining the resulting range of forms and functions.
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Affiliation(s)
- Nicholas F Parnell
- School of Biology, Institute for Bioengineering and Bioscience, Georgia Institute of Technology, 310 Ferst Drive, Atlanta, GA 30332-0230, USA.
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