Multivariate morphometric discrimination among three species of Lutzomyia subgenus Micropygomyia (Diptera: Psychodidae)

Utility of body and otolith morphometry to discriminate cryptic juveniles of two sympatric red snappers (Perciformes: Lutjanidae)

The sympatric red snappers, Lutjanus erythropterus and Lutjanus malabaricus, are highly valued by commercial and recreational fishers along the tropical northern coasts of Australia and throughout their distribution. Studies on the life history and ecology of these congeners are confounded by difficulties in distinguishing the cryptic juveniles of each species (i.e., < 200 mm total length). This study aimed to validate a robust and cost-effective method to discriminate these juveniles using body and/or otolith morphometric data in a multivariate analysis. Juvenile samples were collected from the northwest (n = 71) and northeast (n = 19) coasts of Australia, and species identification was confirmed using DNA barcoding. The most parsimonious multivariate models achieved accurate species prediction rates of 98.8%, which consisted of just three body variables (dorsal fin length, the distance from the snout to the anterior edge of the eye, and either jaw length or distance from the snout to the preoperculum). The high level of discrimination for these cryptic juveniles highlights the robustness of this morphometric approach. The slightly lower rate of discrimination using otolith morphology (84.9%) was associated with greater regional variation in L. malabaricus between the northwest and northeast coasts. Slight variations in otolith shape are typically used to determine stock structure, which highlights the potential need to collect samples over a broader area of a species geographic range when using an otolith morphometric discrimination model. The method outlined in this study could be applied to distinguish other cryptic congeneric fish species, including from archived otolith collections. Moreover, this method has the potential to be utilized in assessing species compositions using body measurements from in situ stereo-video.

Traditional and Geometric Morphometry Analyses of Lutzomyia cruciata (Diptera: Psychodidae: Phlebotominae) Populations of Chiapas, Mexico

The presence of Lutzomyia (Tricholateralis) cruciata (Coquillett 1907) species complex has been suggested by morphological analysis of eggs and genetic studies of females. The present work aimed to compare the diversity in morphology of four populations of Lu. cruciata from the Coast of Chiapas, Mexico, using traditional (TM) and geometric (GM) methods. Several morphological characteristics that were analyzed provided consistency to differentiate at least, three populations of Lu. cruciata. Both methods were effective to detect morphological differences associated with the geographical sites of capture. In both sexes, three and four groups were detected by TM and GM, respectively. These results suggest marked morphological differences in both sexes of Lu. cruciata that make these methods potentially useful to identify the geographical origin of any specimen of this species captured in the study region. Although the results produced by both methods are coincident, geometric morphometrics turned out to be most advantageous with respect to traditional morphometry, since the latter requires more time and effort. The consistency of our results shows that the variability of environmental conditions on the coast of Chiapas determines a high degree of phenotypic plasticity in Lu. cruciata, with the possibility of prezygotic isolation and the formation of species complex.

The role of wing geometric morphometrics in the identification of sandflies within the subgenus Lutzomyia

The Lutzomyia subgenus (Diptera: Psychodidae) includes sibling species with morphologically indistinguishable females. The aims of this study were to analyse variations in the size and shape of wings of species within the Lutzomyia subgenus and to assess whether these analyses might be useful in their identification. Wings (n = 733) of 18 species deposited in Brazilian collections were analysed by geometric morphometrics, using other genera and subgenera as outgroups. Shape variation was summarized in multivariate analyses and differences in wing size among species were tested by analysis of variance. The results showed significant variation in the sizes and shapes of wings of different Lutzomyia species. Two clusters within the Lutzomyia subgenus were distinguished in analyses of both males and females. In Cluster 1 (Lutzomyia ischnacantha, Lutzomyia cavernicola, Lutzomyia almerioi, Lutzomyia forattinii, Lutzomyia renei and Lutzomyia battistinii), scores for correct reclassification were high (females, kappa = 0.91; males, kappa = 0.90), whereas in Cluster 2 (Lutzomyia alencari, Lutzomyia ischyracantha, Lutzomyia cruzi, Lutzomyia longipalpis, Lutzomyia gaminarai and Lutzomyia lichyi), scores for correct reclassification were low (females, kappa = 0.42; males, kappa = 0.48). Wing geometry was useful in the identification of some species of the Lutzomyia subgenus, but did not allow the identification of sibling species such as L. longipalpis and L. cruzi.

The distribution of the Phlebotomus major complex (Diptera: Psychodidae) in Turkey

The taxonomic status and distribution of the morphologically similar members of the Phlebotomus major complex in Turkey are unclear. To examine the utility of traditional morphological characters and molecular markers, sand flies were sampled from 90 localities in eleven different provinces covering a wide geographical range throughout Turkey. The morphometric variability was analysed using multivariate analyses of twelve characters, while mitochondrial cytochrome b (Cyt b) and nuclear elongation factor 1α (EF 1-α) genes were used for molecular discrimination. Three distinct monophyletic lineages were identified based on the phylogenetic analysis of the combined data set of mitochondrial and nuclear gene regions, which were also supported by parsimony haplotype network analysis and AMOVA of Cyt b. The first lineage is restricted to south eastern Turkey and represents the species Phlebotomus syriacus, the second is present mostly in the westernmost and the easternmost localities and represents P. neglectus, and the third member of this complex is distributed across the mid-northern and mid-southern regions. None of the studied morphological characters were found to be sufficient to discriminate between these three members of the P. major s.l. complex; however their presence sympatrically in several localities supports their status as species rather than inter-population variability.

Morphometric and molecular analyses of the sand fly species Lutzomyia shannoni (Diptera: Psychodidae: Phlebotominae) collected from seven different geographical areas in the southeastern United States

A morphometric and molecular study of adult male and female Lutzomyia shannoni (Dyar 1929) collected at seven different locations within the southeastern United States was conducted to assess the degree of divergence between the grouped specimens from each location. The collection locations were as follows: Fort Bragg, NC; Fort Campbell, KY; Fort Rucker, AL; Ossabaw Island, GA; Patuxent National Wildlife Research Refuge, MD; Suwannee National Wildlife Refuge, FL; and Baton Rouge, LA. Forty males and forty females from each location were analyzed morphometrically from 54 and 49 character measurements, respectively. In addition, the molecular markers consisting of the partial cytochrome c oxidase subunit I (from 105 sand flies: 15 specimens/collection site) and the partial internal transcribed spacer 2 (from 42 sand flies: six specimens/collection site) were compared. Multivariate analyses indicate that the low degree of variation between the grouped specimens from each collection site prevents the separation of any collection site into an entity that could be interpreted as a distinct population. The molecular analyses were in concordance with the morphometric study as no collection location grouped into a separate population based on the two partial markers. The grouped specimens from each collection site appear to be within the normal variance of the species, indicating a single population in the southeast United States. It is recommended that additional character analyses of L. shannoni based on more molecular markers, behavioral, ecological, and physiological characteristics, be conducted before ruling out the possibility of populations or a cryptic species complex within the southeastern United States.