1
|
Thurman CL, Shih HT, McNamara JC. Minuca panema (Coelho, 1972): Resurrection of a Fiddler Crab Species from Brazil Closely Related to Minuca burgersi (Holthuis, 1967) (Crustacea, Decapoda, Brachyura, Ocypodidae). Zool Stud 2023; 62:e45. [PMID: 37965297 PMCID: PMC10641435 DOI: 10.6620/zs.2023.62-45] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Accepted: 07/09/2023] [Indexed: 11/16/2023]
Abstract
We redescribe a species of fiddler crab, Minuca panema (Coelho, 1972), from the Atlantic coast of South America. It is closely related to M. mordax (Smith, 1870), and until now, the taxon has been considered to be synonymous with another closely related species Minuca burgersi (Holthuis, 1967). However, we found that two clades of M. burgersi sensu lato were restricted to the Caribbean Basin. This distribution differs from than that of M. panema, which occurs primarily along the eastern coast of South America, ranging from the island of Trinidad to Praia da Armação, Santa Catarina, Brazil. Based on our field studies, the geographical boundary between M. burgersi sensu stricto and M. panema is the Tobago Basin, north of Trinidad. Since the two species diverged only 3 to 4 million years ago, as dated from the phylogeny of the genus Minuca Bott 1954, there are few reliable morphological features that can be used to distinguish them clearly. In live crabs, there is a striking difference in coloration between the cherryred South American M. panema and the rusty-red Caribbean M. burgersi sensu lato. In males, the pattern of tubercles on the inner surface of the major cheliped varies between the two species. In females, the vulva is slightly larger in M. burgersi sensu stricto. Ocean tides and currents together with siltation owing to freshwater outflow from the Amazon and Orinoco rivers most likely have driven the divergence of these species. In the Caribbean, small tidal amplitudes have minimized long-distance gene flow in M. burgersi sensu stricto from isolated insular lagoons. In contrast, large tidal amplitudes and exposed habitats on riverbanks along the eastern Atlantic coast of South America have enabled long-distance dispersal in M. panema. DNA analysis reveals that haplotypes of cytochrome c oxidase subunit 1 are not shared between the species. Since natural selection and/or genetic drift have yet to produce extensive morphological divergences between M. panema and M. burgersi sensu stricto, we speculate that changes in the genes regulating mitochondrial DNA functions have led to speciation at the molecular level. According to the mitonuclear compatibility concept, we propose that mitochondrial DNA may be at the forefront of speciation events and that co-evolved mitonuclear interactions are responsible for some of the earliest genetic incompatibilities arising among isolated populations.
Collapse
Affiliation(s)
- Carl L Thurman
- Department of Biology, University of Northern Iowa, 1227 West 27th St., Cedar Falls, IA 50614-0421, USA. E-mail: (Thurman). Tel: +1 319 273-2276
| | - Hsi-Te Shih
- Department of Biology, University of Northern Iowa, 1227 West 27th St., Cedar Falls, IA 50614-0421, USA. E-mail: (Thurman). Tel: +1 319 273-2276
| | - John C McNamara
- Departamento de Biologia, FFCLRP, Universidade de São Paulo, Ribeirao Preto 14040-901, Brazil. E-mail: (McNamara). Tel: +55 16 3315 3687
- Centro de Biologia Marinha, Universidade de São Paulo, 11600-000 SP, Brazil
| |
Collapse
|
2
|
Shih HT, Naruse T, Schubart CD. Molecular evidence and differences in gonopod morphology lead to the recognition of a new species of the freshwater crab genus Candidiopotamon Bott, 1967 (Crustacea, Brachyura, Potamidae) from eastern Taiwan. Zookeys 2023; 1179:169-196. [PMID: 37731535 PMCID: PMC10507446 DOI: 10.3897/zookeys.1179.106718] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Accepted: 08/19/2023] [Indexed: 09/22/2023] Open
Abstract
A new freshwater crab of the potamid genus Candidiopotamon Bott, 1967, is described from eastern Taiwan. Candidiopotamonpenglai sp. nov. is morphologically similar to C.rathbuni (De Man, 1914) from western Taiwan, but can be distinguished by the morphology of the male first gonopod (G1), as well as by their mitochondrial DNA (16S rRNA and COI genes). In the G1 of C.rathbuni, the subterminal segment shows a cline from robust in northern populations to slender in southern populations. In the G1 of C.penglaisp. nov., a distinctly larger and more distally directed keel-like projection is found on the distal inner edge of the terminal segment, with northern populations having an inward-curving subterminal segment and southern populations a straight subterminal segment. The genetic differentiation of the two species of Candidiopotamon within Taiwan is discussed, and morphological differences are compared. A key to the species of Candidiopotamon is also provided.
Collapse
Affiliation(s)
- Hsi-Te Shih
- Department of Life Science and Global Change Biology Research Center, National Chung Hsing University, 250, Kuo Kuang Road, Taichung 402, TaiwanNational Chung Hsing UniversityTaichungTaiwan
| | - Tohru Naruse
- Tropical Biosphere Research Center, Iriomote Station, University of the Ryukyus, 870 Uehara, Taketomi, Okinawa 907-1541, JapanUniversity of the RyukyusOkinawaJapan
| | - Christoph D. Schubart
- Zoology & Evolution, University of Regensburg, 93040 Regensburg, GermanyUniversity of RegensburgRegensburgGermany
| |
Collapse
|
3
|
Zhang YC, Shih HT. First Zoeal Stage of 15 Species of Fiddler Crabs (Crustacea: Brachyura: Ocypodidae) from Taiwan. Zool Stud 2022; 61:e71. [PMID: 36644631 PMCID: PMC9810989 DOI: 10.6620/zs.2022.61-71] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Accepted: 06/13/2022] [Indexed: 01/17/2023]
Abstract
Fiddler crabs (Brachyura: Ocypodidae: Gelasiminae) in Taiwan consist of 5 genera and 15 species, but knowledge of their larval development is limited to just 3 species, namely Austruca lactea, Tubuca arcuata, and Xeruca formosensis. In our study, the morphology of the first zoeal stage (zoea I) of the 15 species is described and compared to previous studies. The results show that the characters of zoea I can be used to distinguish the five studied genera and most species (except three groups, "Gelasimus borealis, G. jocelynae and G. vocans", "Paraleptuca crassipes and P. splendida" and "Tubuca arcuata, T. coarctata and T. paradussumieri"). The lateral spines on the carapace in zoea I are suggested to be a unique character in the Ocypodinae because they are absent in the Gelasiminae and Ucidinae, which supports the current systematics of the Ocypodidae.
Collapse
Affiliation(s)
- Ying-Chen Zhang
- Department of Life Science, National Chung Hsing University, 250 Kuo Kuang Road, Taichung 402, Taiwan. E-mail: (Zhang)
| | - Hsi-Te Shih
- Department of Life Science, National Chung Hsing University, 250 Kuo Kuang Road, Taichung 402, Taiwan. E-mail: (Zhang)
- Research Center for Global Change Biology, National Chung Hsing University, 250 Kuo Kuang Road, Taichung 402, Taiwan. E-mail: (Shih)
| |
Collapse
|
4
|
Diversity and Distribution of Fiddler Crabs (Crustacea: Brachyura: Ocypodidae) in Vietnam. Zool Stud 2022; 61:e66. [PMID: 36644629 PMCID: PMC9811167 DOI: 10.6620/zs.2022.61-66] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 04/07/2022] [Indexed: 01/17/2023]
Abstract
Based on recently collected material and records in the literature, 14 species of fiddler crabs (Crustacea: Ocypodidae: Gelasiminae) are reported from Vietnam. DNA barcoding analyses using the mitochondrial gene COI (cytochrome c oxidase subunit I) was performed to identify examined materials and their precise distributional range. Thirteen species-level taxa are identified and, with the exception of Galsimus borealis and G. vocans, have minimum interspcific divergences of at least 7.27%. The identified species include seven species of Tubuca Bott, 1973, three of Austruca Bott, 1973 and three of Gelasimus Latreille, 1817, and one Paraleptuca Bott, 1973. Two new records of Vietnam are herein reported: Tubuca rhizophorae and T. dussumieri. The southernmost distribution limits of East Asian G. borealis, T. acuta and T. arcuata are in northern Vietnam, A. lactea in central Vietnam, whereas northernmost limit of Southeast Asian T. rhizophorae and T. forcipata in southern Vietnam. A dichotomous key to identify the 14 Vietnamese species is provided.
Collapse
|
5
|
Shih HT, Chan BKK. Systematics and Biogeography of Fiddler Crabs -A Special Issue in Zoological Studies. Zool Stud 2022; 61:e64. [PMID: 36568822 PMCID: PMC9755984 DOI: 10.6620/zs.2022.61-64] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 09/09/2022] [Indexed: 12/27/2022]
Abstract
Fiddler crabs are a fantastic group of intertidal brachyuran crabs, and the research fields focused on their biodiversity, phylogeography, phylogenomics, and larval biology are still in developing stages. In this special issue, seven articles are included focusing on the diversity, phylogeography, mitogenome phylogeny and larval morphology of fiddler crabs, covering the regions of the Indo-West Pacific and Americas. Results from this special issue open up further opportunities to study new species identification based on an integrative taxonomy approach, genomic-level phylogeny and larval morphology, especially in regards to the mitogenomes in the genera Cranuca, Gelasimus, Paraleptuca, and Uca for filling up the knowledge gap of fiddler crabs in the world.
Collapse
Affiliation(s)
- Hsi-Te Shih
- Department of Life Science and Research Center for Global Change Biology, National Chung Hsing University, Taichung 402, Taiwan. E-mail: (Shih)
| | - Benny K K Chan
- Biodiversity Research Center, Academia Sinica, Taipei 115, Taiwan. E-mail: (Chan)
| |
Collapse
|
6
|
Diversity in the Taiwanese Swimming Crabs (Crustacea: Brachyura: Portunidae) Estimated through DNA Barcodes, with Descriptions of 14 New Records. Zool Stud 2021; 60:e60. [PMID: 35774269 PMCID: PMC9168908 DOI: 10.6620/zs.2021.60-60] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 07/14/2021] [Indexed: 12/29/2022]
Abstract
The swimming crabs (family Portunidae) are distributed worldwide and commonly inhabit estuaries, mangroves, reefs, shallow and the deep sea. Previously, 75 species and 19 genera in this family were known to Taiwan. Our study examined specimens in Taiwanese waters, including the islands, collected between 2016 and 2020 or deposited in museums. Through the cytochrome oxidase subunit I DNA barcode marker and morphological examination, 71 species were identified. The minimum interspecific distances were greater than 4.09%, except in two unresolved groups: Charybdis miles (De Haan, 1835) and Ch. sagamiensis Parisi, 1916, as well as Thranita pelsarti (Montgomery, 1931) and Thr. prymna (Herbst, 1803). In addition, 14 species belonging to nine genera were confirmed as new records to Taiwan, viz. Carupa ohashii Takeda, 1993, Lupocyclus inaequalis (Walker, 1887), Luu. tugelae Barnard, 1950, Lupocycloporus minutus (Shen, 1937), Monomia gladiator (Fabricius, 1798), M. lucida Koch & Ďuriš, 2018, Podophthalmus minabensis Sakai, 1961, Thalamita gatavakensis Nobili, 1906, Tha. spinifera Borradaile, 1902, Thalamitoides quadridens A. Milne-Edwards, 1869, Tho. tridens A. Milne-Edwards, 1869, Thr. cerasma (Wee & Ng, 1995), Thr. coeruleipes (Hombron & Jacquinot, 1846) and Xiphonectes tuberculosus (A. Milne-Edwards, 1861). This study thus raises the total number of Portunidae species in Taiwan to 89.
Collapse
|
7
|
Diversity of Taiwanese Brackish Crabs Genus Ptychognathus Stimpson, 1858 (Crustacea: Brachyura: Varunidae) based on DNA Barcodes, with Descriptions of Two New Species. Zool Stud 2020; 59:e59. [PMID: 34149907 DOI: 10.6620/zs.2020.59-59] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 09/14/2020] [Indexed: 11/18/2022]
Abstract
Species in the brackish crab genus Ptychognathus are common in the seashore and estuary habitats with freshwater input. Due to their similar morphologies and dull colorations, it is always difficult to distinguish the species in this genus. In this study, the DNA barcode gene COI (cytochrome c oxidase subunit I) was used to help identify Ptychognathus from Taiwan. The results showed that the 10 species can be identified successfully based on COI, with intraspecific distances below 1.54% and interspecific distances of 12.2%-19.57%. In addition, two new species of Ptychognathus are described from Taiwan. Ptychognathus makii sp. nov. from southern Taiwan is similar to P. altimanus (Rathbun, 1914), and P. stimpsoni sp. nov. from southern Taiwan and the southern Philippines resembles P. aff. barbatus (A. Milne-Edwards, 1873) and P. pusillus Heller, 1865. Both species can be distinguished from other congeners by a suite of characters, including the carapace, orbital region, frontal region, telson of male pleon, male first gonopod, and setae on ambulatory legs.
Collapse
|
8
|
Ng PKL, Li JJ, Shih HT. What is Sesarmops impressus (H. Milne Edwards, 1837) (Crustacea: Brachyura: Sesarmidae)? Zool Stud 2020; 59:e27. [PMID: 33262850 PMCID: PMC7688423 DOI: 10.6620/zs.2020.59-27] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Accepted: 05/13/2020] [Indexed: 01/04/2023]
Abstract
The identity of the widely distributed mangrove and riverine sesarmid crab Sesarmops impressus (H. Milne Edwards, 1837) is clarified. The species has been reported from Madagascar to the South Pacific, but its taxonomy was previously confused. On the basis of morphological characters and available molecular evidence (using 16S rDNA and cytochrome oxidase subunit I), Sesarmops impressus is restricted to the western Indian Ocean and S. frontale A. Milne-Edwards, 1869 is confirmed to be its junior synonym. Sesarmops similis (Hess, 1865), long synonymised under S. impressus, is here recognised as a separate species and a neotype from Samoa is designated. The identity of the poorly known S. atrorubens (Hess, 1865), which has often been confused with S. impressus, is also clarified, and a neotype is selected from Fiji. Specimens from the eastern Indian Ocean and western Pacific are here identified as two new species, S. indicus sp. nov. and S. imperator sp. nov.
Collapse
Affiliation(s)
- Peter K L Ng
- Lee Kong Chian Natural History Museum, National University of Singapore, 2 Conservatory Drive, Singapore 117377, Republic of Singapore. E-mail: (Ng)
| | - Jheng-Jhang Li
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, 70, Lianhai Road, Kaohsiung 80424, Taiwan. E-mail: (Li)
- East Peak Ecological Consultants, Inc., 22, Wanggong Road, Linyuan Dist., Kaohsiung 83249, Taiwan
| | - Hsi-Te Shih
- Department of Life Science and Research Center for Global Change Biology, National Chung Hsing University, 250, Kuo Kuang Road, Taichung 402, Taiwan. E-mail: (Shih)
| |
Collapse
|
9
|
A New Fiddler Crab of Austruca Bott, 1973, Closely Related to A. perplexa (H. Milne Edwards, 1852) (Crustacea: Brachyura: Ocypodidae), from the South Pacific Islands. Zool Stud 2020; 59:e26. [PMID: 33262849 DOI: 10.6620/zs.2020.59-26] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Accepted: 05/20/2020] [Indexed: 11/18/2022]
Abstract
A new species of fiddler crab, Austruca citrus n. sp. from Fiji, Wallis & Futuna, and Samoa, in the South Pacific is described based on morphological and molecular evidence. This species is closely related to Austruca perplexa (H. Milne Edwards, 1852), but can be distinguished by a suite of characters, including adult size, carapace morphology, shape and coloration of the major chela, the ratio of major pollex length as a function of carapace width, and male first gonopod form. The molecular evidence of the mitochondrial 16S rDNA and cytochrome oxidase subunit I (COI) supports these morphological differences.
Collapse
|
10
|
Resurrection of Gelasimus variegatus Heller, 1862, A Fiddler Crab Closely Related to Austruca bengali (Crane, 1975) and A. triangularis (A. Milne-Edwards, 1873) (Decapoda, Brachyura, Ocypodidae), from the Bay of Bengal, Indian Ocean. Zool Stud 2020; 58:e12. [PMID: 31966313 DOI: 10.6620/zs.2019.58-12] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 05/19/2019] [Indexed: 11/18/2022]
Abstract
The identity of the fiddler crab, Gelasimus variegatus Heller, 1862 (type locality: Madras, India), has long been uncertain. Examination of specimens from the Bay of Bengal shows that it is a valid species belonging to the genus Austruca Bott, 1973. Austruca variegata (Heller, 1862) can be separated from the closely related A. bengali (Crane, 1975) and A. triangularis (A. Milne-Edwards, 1873) by characters of the carapace, orbital floor, major and minor chelae, male first gonopod, vulva (female gonopore), gastric mill, and coloration in life. The three species are also supported by genetic data (nuclear 28S rDNA, mitochondrial 16S rDNA and cytochrome oxidase subunit I (COI)). Biogeographically, A. variegata is distributed in the Bay of Bengal and reaches to the Laccadive Sea; A. bengali is present in the Andaman Sea; and A. triangularis is widely distributed in the West Pacific.
Collapse
|
11
|
Marin IN, Spiridonov VA, Ng PK. A New Species of the Aberrant Majid Crab Genus Planotergum Balss, 1935 (Crustacea: Brachyura, Majidae, Planoterginae) from the Southern Red Sea. Zool Stud 2019; 58:e26. [PMID: 31966327 PMCID: PMC6917560 DOI: 10.6620/zs.2019.58-26] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 07/22/2019] [Indexed: 06/10/2023]
Abstract
A new species of the aberrant monotypic genus Planotergum Balss, 1935 (Brachyura: Majidae: Planoterginae) is described from the southern part of the Red Sea, based on a single female recently found in the collection of the Zoological Museum of Moscow State University. The new species is clearly distinguished from Planotergum mirabile Balss, 1935 in the form of carapace, antennal article and third maxilliped, as well as morphology of the ambulatory legs. The record extends the known range of Planotergum, previously known only from the eastern Indian Ocean and Western Pacific, by more than 7000 km.
Collapse
Affiliation(s)
- Ivan N. Marin
- A.N. Severtzov Institute of Ecology and Evolution of RAS,
Moscow, 119071, Russia
- Biological Department, Altai State University, Barnaul,
Russia.
| | - Vassily A. Spiridonov
- Shirshov Institute of Oceanology, Russian Academy of
Sciences, Nakhimovsky Prospekt, 36, Moscow, 117997, Russia. E-mail:
| | - Peter K.L. Ng
- Lee Kong Chian Natural History Museum, Faculty of
Science, National University of Singapore, 2 Conservatory Drive, Singapore 117377,
Republic of Singapore. E-mail:
| |
Collapse
|
12
|
Subdividing the Common Intertidal Hermit Crab Pagurus minutus Hess, 1865 (Decapoda: Anomura: Paguridae) Based on Molecular, Morphological and Coloration Analyses. Zool Stud 2018; 57:e61. [PMID: 31966301 DOI: 10.6620/zs.2018.57-61] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Accepted: 11/23/2018] [Indexed: 11/18/2022]
Abstract
Jibom Jung, Jongwoo Jung, and Won Kim (2018) A phylogenetic study was conducted to investigate whether distinct genetic groups are present within the East Asian Pagurus minutus. In this study, 167 individuals of P. minutus were collected along the coasts of South Korea, east coast of Honshu, west coast of Kyushu, Okinawa Islands of Japan, and Taiwan. The collection of P. minutus was divided into three groups based on the differences in cytochrome c oxidase subunit I (COI) sequences and morphological and color characters: Major Group (MAG), Minor Group (MIG), and Taiwan-Okinawa Group (TOG). MAG commonly inhabits the entire coast of South Korea (except for the northeast coast), east coast of Honshu, and west coast of Kyushu in Japan. MIG predominantly inhabits the northeast coast of South Korea, while a small proportion inhabits the west coast of South Korea and west coast of Kyushu in Japan. TOG is restricted to Taiwan and the Okinawa Islands of Japan. The COI divergence among MAG, MIG, and TOG was larger than the minimum interspecific divergence of the other Pagurus species. Little ingroup COI divergences exist in the MAG and MIG, but distinct ingroup COI divergence is present between the two subgroups of TOG inhabiting Taiwan and Okinawa Islands. MAG, MIG, and TOG show minor differences among morphological characters. Each specimen of these three groups has distinguishing color patterns. These differences in molecular, morphological and color characters suggest that P. minutus are separated into three groups at the species level, and this subdivision of P. minutus shows that additional phylogenetic studies of other hermit crabs and common marine decapod species in East Asia are needed.
Collapse
|
13
|
Thurman CL, Hopkins MJ, Brase AL, Shih HT. The unusual case of the widely distributed fiddler crab Minuca rapax (Smith, 1870) from the western Atlantic: an exemplary polytypic species. INVERTEBR SYST 2018. [DOI: 10.1071/is18029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A classic dilemma in taxonomy is distinguishing intraspecific from interspecific variation. In order to better comprehend the process of divergence and speciation, we examine morphological, genetic, developmental and behavioural variation among related fiddler crab populations from eastern North America, the Caribbean and South America. We chose geographically remote populations that appear related to Minuca rapax (Smith, 1870). First, using females from across the range of the species, we use geometric morphometric techniques to identify regional differences in carapace shape. Second, in the northern portion of the range, the Caribbean into the Gulf of Mexico, we report variation in the relationship between corporal size and cheliped length in males. Third, we examine the major components of the courtship waves produced by males from several locations in the western Gulf of Mexico. Fourth, we compare the structure of the gastric mill between different populations in the Gulf of Mexico, the Caribbean and the Atlantic Ocean. And, fifth, we use mitochondrial 16S rDNA and cytochrome oxidase subunit I as genetic markers to define the phylogeographic relationship among specimens from more than 20 populations. From these studies, we find discrete, distinct populations across the original range of the species. In particular, populations in the northern Gulf of Mexico appear to represent a lineage that has resulted from limited gene flow and sustained selection pressures. On the basis of the observed degree of divergence, it is apparent that some separated populations in M. rapax should be recognised as evolutionary significant units. The geographic range of these populations is consistent with the historical range for Minuca virens (Salmon & Atsaides, 1968), a putative species that otherwise cannot be consistently distinguished from M. rapax based on discrete external morphological characters. This study provides evidence for M. virens as an emergent but possibly not completely isolated subclade of the M. rapax species complex.
Collapse
|