Disappearing apple snails (Caenogastropoda: Ampullariidae) of Thailand: a comprehensive update of their taxonomic status and distribution

2020 ◽  
Vol 86 (4) ◽  
pp. 290-305 ◽  
Author(s):  
Ting Hui Ng ◽  
Supunya Annate ◽  
Ekgachai Jeratthitikul ◽  
Chirasak Sutcharit ◽  
Yanin Limpanont ◽  
...  
Keyword(s):  
Cryptic Species ◽  
Taxonomic Status ◽  
Intraspecific Diversity ◽  
Human Consumption ◽  
Conservation Action ◽  
Separate Species ◽  
High Genetic Diversity ◽  
Geometric Morphometric ◽  
Geometric Morphometric Analysis ◽  
Species Taxonomy

ABSTRACT Ampullariidae include the largest of all freshwater snails and are of ecological, evolutionary and anthropogenic importance in Southeast Asia (SEA). Native ampullariids belonging to the genus Pila face various threats but are understudied, with their species taxonomy being confused and data on their distributions being scarce. We provide a comprehensive update on the nomenclature, status and distribution of Pila species in Thailand, based on DNA barcoding and geometric morphometric analysis of recently collected material. We confirm that at least five Pila species are extant in Thailand: Pila virescens, P. celebensis, P. turbinis, P. gracilis and P. pesmei. Pila celebensis, which has distinctive egg masses among all the known Southeast Asian Pila, appears to be sister to a clade comprising other SEA and some African Pila. Our results suggest that Pila may have dispersed into SEA on at least two separate occasions. Two singletons collected from northern and eastern Thailand may constitute separate species, but this requires further study. Intraspecific diversity of the mitochondrial cytochrome c oxidase subunit I gene was relatively high for P. celebensis, P. gracilis and P. pesmei (maximum uncorrected p-distances varied from 7% to 9%), and may include cryptic species. Conversely, P. virescens showed low intraspecific p-distances (c. 0%) among clades collected from different localities. This strongly suggests that introductions by humans may be the major cause of this pattern, and our own observations—we found that this species is being cultured and is commonly sold in markets for human consumption—are consistent with this. Pila turbinis was the rarest species, with live snails being collected from only two localities. Throughout Thailand, invasive confamilial Pomacea species appear to be replacing native Pila species, particularly in the Chao Phraya basin. While Thai Pila exhibit surprisingly high genetic diversity, with cryptic species likely being present, widespread invasive snails pose a major threat to their survival and urgent conservation action is needed.

Analysis of the differences between Syntormon pallipes and S. pseudospicatus (Diptera: Dolichopodidae): morphological and molecular data

2019 ◽  
Vol 28 (2) ◽  
pp. 305-316
Author(s):  
M.A. Chursina ◽  
I.Ya. Grichanov
Keyword(s):  
Dna Analysis ◽  
Distinct Species ◽  
Molecular Data ◽  
Wing Shape ◽  
Morphological Data ◽  
12S Rrna ◽  
Separate Species ◽  
Geometric Morphometric ◽  
Geometric Morphometric Analysis ◽  
Morphological And Molecular Data

The recent catalogues of the family Dolichopodidae considered Syntormon pallipes (Fabricius, 1794) and S. pseudospicatus Strobl, 1899 as separate species. In this study, we used three approaches to estimate the significance of differences between the two species: molecular analysis (COI and 12S rRNA sequences), analysis of leg colour characters and geometric morphometric analysis of wing shape. The morphological data confirmed the absence of significant differences between S. pallipes and S. pseudospicatus found in the DNA analysis. Significant differences in the wing shape of two species have not been revealed. Hence, according to our data, there is no reason to consider S. pseudospicatus as a distinct species.

scholarly journals On two species of Riocypris (Crustacea, Ostracoda) from northern Patagonia and their relation to Eucypris fontana: implications in paleoenvironmental reconstructions

2018 ◽  
Vol 96 (8) ◽  
pp. 801-817 ◽  
Author(s):  
C.A. Coviaga ◽  
A.P. Pérez ◽  
L.Y. Ramos ◽  
P. Alvear ◽  
G.C. Cusminsky
Keyword(s):  
Sexual Dimorphism ◽  
Morphometric Analysis ◽  
Indicator Species ◽  
Taxonomic Status ◽  
Geometric Morphometric ◽  
Comparative Analyses ◽  
Northern Patagonia ◽  
Geometric Morphometric Analysis ◽  
The Individual ◽  
First Time

Two species of ostracods new to Patagonia, Argentina, are described. One of them, Riocypris whatleyi sp. nov., is described for the first time, and the second, Riocypris sarsi (Daday, 1902) comb. nov., is reallocated from genus Eucypris to genus Riocypris. Inter- and intra-specific variations in shape, size, and sexual dimorphism were evaluated based on geometric morphometric analysis. Moreover, morphological and morphometric comparative analyses were applied to re-examine living and quaternary specimens recovered from previous studies. Based on these results, a generic reassignment for the Patagonian Eucypris fontana (Jurine, 1820) into the genus Riocypris is proposed. Contributing to the knowledge on the systematic and autecology of this enigmatic species, widely distributed in Patagonia and frequently used in paleolimnological reconstructions, generates science-based evidence for their use as indicator species. Additionally, our results emphasize the usefulness of studying the living representatives (i.e., with valves and appendages) for elucidating the taxonomic status of the individual specimens, especially those present in paleontological records and used as bioproxies in paleolimnological studies.

scholarly journals DNA barcodes combined with geometric morphometry challenge species hypothesis in palaemonid shrimp

2021 ◽  
Vol 4 ◽  
Author(s):  
Aleksandra Jablonska ◽  
Nicolas Navarro ◽  
Remi Laffont ◽  
Remi Wattier ◽  
Vladimir Pesic ◽  
...  
Keyword(s):  
Taxonomic Status ◽  
Balkan Peninsula ◽  
Integrative Approach ◽  
Shape Variation ◽  
Separate Species ◽  
Geometric Morphometric ◽  
The Balkans ◽  
Operational Taxonomic Units ◽  
Freshwater Shrimps ◽  
Coi Sequences

Although the Mediterranean Region is known as a hotspot for biodiversity and endemism its freshwater fauna is still greatly unexplored, and even the emblematic taxa such as decapods require in-depth integrative investigation. In our research we used integrative approach composed of various geometric morphometric and molecular methods to challenge the taxonomic status of two freshwater shrimps representing Palaemonidae: Palaemon antennarius and Palaemon minos. Basing on 352 COI sequences, three Molecular Operational Taxonomic Units (MOTUs) were defined. Two of them belonged to P. antennarius: first inhabiting Apennine Peninsula and Sicily, the second one from the Balkan Peninsula. The third MOTU corresponded to Palaemon minos from Crete. The Balkan MOTU of P. antennarius was closer to P. minos in terms of genetics, than to the other conspecific MOTU. The carapace shape variation, studied on 180 individuals, was mainly explained by the geographic distribution. Balkan and Cretan groups were clearly distinguished, while other samples were distributed along the shape gradient from Sicily and southern Apennine Peninsula to the Balkans. The results of our study showed that, either the MOTU assigned to the Apennine Peninsula and Sicily constitutes a separate species or, alternatively, P. minos should be synonymised with P. antennarius.

scholarly journals High genetic diversity and presence of genetic structure characterise the Corso-Sardinian endemics Ruta corsica and Ruta lamarmorae (Rutaceae)

2018 ◽  
Author(s):  
Marilena Meloni ◽  
Caterina Angela Dettori ◽  
Andrea Reid ◽  
Gianluigi Bacchetta ◽  
Laetitia Hugot ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Genetic Structure ◽  
Biological Diversity ◽  
Taxonomic Status ◽  
Single Species ◽  
Dispersal Ability ◽  
Separate Species ◽  
High Genetic Diversity ◽  
History Of

SummaryCorsica and Sardinia form one of the ten areas with highest biodiversity in the Mediterranean and are considered one of the priority regions for conservation in Europe. In order to preserve the high levels of endemism and biological diversity at different hierarchical levels, knowledge of the evolutionary history and current genetic structure of Corso-Sardinian endemics is instrumental. Microsatellite markers were newly developed and used to study the genetic structure and taxonomic status of Ruta corsica and Ruta lamarmorae, rare endemics of Corsica and Sardinia, respectively, and previously considered a single species. Our analyses identified high levels of genetic variation within each species (P=0.883, He=0.543 for R. corsica; P=0.972, He=0.627 for R. lamarmorae). Intrinsic traits of the species (hermaphroditism, proterandry and polyploidy) and island-dependent factors (i.e. age, origin and history of the islands) might explain the detected high levels of genetic variation. We discovered differentiation between R. corsica and R. lamarmorae, and genetic structure within each species, which are consistent with the observation of low dispersal ability for both species. Our genetic results support the recent taxonomic classification of R. corsica and R. lamarmorae as separate species and suggest that they diverge at only few loci. One R. corsica population (SA) strongly differed from all other studied populations and appeared to be the product of hybridization between the two species in STRUCTURE analyses. Our results provide important insights for the conservation of the two rare endemics. Further genetic analyses are recommended for R. lamarmorae and for population SA (R. corsica).

scholarly journals Geometric morphometric analysis of the skull of Podocnemis spp. (Pleurodira, Podocnemididae) and its implications on the taxonomic status of Podocnemis bassleri Williams, 1956

2015 ◽  
Author(s):  
Pedro S. R. Romano ◽  
Sergio A. K. Azevedo ◽  
Alexander W. A. Kellner ◽  
Gustavo R. Oliveira
Keyword(s):  
Multivariate Regression ◽  
Phylogenetic Signal ◽  
Ventral View ◽  
Taxonomic Status ◽  
Shape Variation ◽  
Diagnostic Features ◽  
Geometric Morphometric ◽  
Geometric Morphometric Analysis ◽  
Independent Variable ◽  
The Individual

Background. Podocnemis bassleri Williams, 1956 is the oldest definite record for Podocnemis, dating back to the Miocene of South America. However, the diagnosis of P. ba. is fragile, as assumed by Williams himself. Here we evaluated the hypothesis of P. ba. as a synonym of P. expansa by exploring the shape variation of the skull among Podocnemis spp. Methods. We collected 19 landmarks on the left side of the skull in ventral view from 33 Podocnemis spp. skulls. We included in the sample a new specimen of P. ba. from the Miocene of Acre, Brazil (MCT/RJ unnumbered) and the holotype (AMNH 1662) from the Miocene of Peru, along with: P. erythrocephala (n=3), P. ex. (n=9), P. lewyana (n=1), P. sextuberculata (n=9), P. unifilis (n=6), and P. vogli (n=3). The data was then Procrustes superimposed and a Relative Warps Analysis (RW) was performed to evaluate shape variation. Also, a multivariate regression of the Partial Warps (i.e.: the eigenvectors of the “bending energy” matrix) versus the log-transformed centroid size (the independent variable) was computed in order to evaluate the allometry in the data. All analyses were fulfilled using Rohlf’s TPS softwares. Results. The two first RWs accumulated ~52% of shape variation. The individual projection of the specimens in RW1 and RW2 showed a structure partially explained by a phylogenetic signal. P. ex. and P. se., previously considered as sister-groups, were projected in the negative scores of RW1. Also, these two species were projected, respectively, in the positive and negative scores of the RW2. The two specimens of P. ba. were nested among P. ex. specimens. Furthermore, the multivariate regression revealed an effect of the size in the shape variation: larger skulls have wider maxillae and posterior region laterally extended. Discussion. According to the literature, P. ex. and P. ba. are nearly indistinguishable (besides the larger size of the second), and Williams seems to have used the Miocene age of the second as a criterion for differentiating the two taxa. Indeed, one of the diagnostic features pointed out by Williams – slightly shorter relative distance from snout tip to posterior borders of the orbits – seems to be a taphonomic outcome. Moreover, the second diagnostic character – internal palatal processes of the maxillae abruptly dorsally projected – is extended anteroposteriorly in the MCT/RJ P. ba. specimen, as in all recent taxa. So, this character is polymorphic or also results of a taphonomic outcome. As consequence, P. ba. lacks a suitable diagnosis. Our preliminary results revealed little differences in shape of P. ex. and P. ba. and a clear allometric effect in the shape variation. In conclusion, it seems reasonable to suggest that P. ba. is a junior synonym of P. ex., although we will wait to claim it after additional analyses.

scholarly journals Geometric morphometric analysis of the skull of Podocnemis spp. (Pleurodira, Podocnemididae) and its implications on the taxonomic status of Podocnemis bassleri Williams, 1956

2015 ◽  
Author(s):  
Pedro S. R. Romano ◽  
Sergio A. K. Azevedo ◽  
Alexander W. A. Kellner ◽  
Gustavo R. Oliveira
Keyword(s):  
Multivariate Regression ◽  
Phylogenetic Signal ◽  
Ventral View ◽  
Taxonomic Status ◽  
Shape Variation ◽  
Diagnostic Features ◽  
Geometric Morphometric ◽  
Geometric Morphometric Analysis ◽  
Independent Variable ◽  
The Individual

Background. Podocnemis bassleri Williams, 1956 is the oldest definite record for Podocnemis, dating back to the Miocene of South America. However, the diagnosis of P. ba. is fragile, as assumed by Williams himself. Here we evaluated the hypothesis of P. ba. as a synonym of P. expansa by exploring the shape variation of the skull among Podocnemis spp. Methods. We collected 19 landmarks on the left side of the skull in ventral view from 33 Podocnemis spp. skulls. We included in the sample a new specimen of P. ba. from the Miocene of Acre, Brazil (MCT/RJ unnumbered) and the holotype (AMNH 1662) from the Miocene of Peru, along with: P. erythrocephala (n=3), P. ex. (n=9), P. lewyana (n=1), P. sextuberculata (n=9), P. unifilis (n=6), and P. vogli (n=3). The data was then Procrustes superimposed and a Relative Warps Analysis (RW) was performed to evaluate shape variation. Also, a multivariate regression of the Partial Warps (i.e.: the eigenvectors of the “bending energy” matrix) versus the log-transformed centroid size (the independent variable) was computed in order to evaluate the allometry in the data. All analyses were fulfilled using Rohlf’s TPS softwares. Results. The two first RWs accumulated ~52% of shape variation. The individual projection of the specimens in RW1 and RW2 showed a structure partially explained by a phylogenetic signal. P. ex. and P. se., previously considered as sister-groups, were projected in the negative scores of RW1. Also, these two species were projected, respectively, in the positive and negative scores of the RW2. The two specimens of P. ba. were nested among P. ex. specimens. Furthermore, the multivariate regression revealed an effect of the size in the shape variation: larger skulls have wider maxillae and posterior region laterally extended. Discussion. According to the literature, P. ex. and P. ba. are nearly indistinguishable (besides the larger size of the second), and Williams seems to have used the Miocene age of the second as a criterion for differentiating the two taxa. Indeed, one of the diagnostic features pointed out by Williams – slightly shorter relative distance from snout tip to posterior borders of the orbits – seems to be a taphonomic outcome. Moreover, the second diagnostic character – internal palatal processes of the maxillae abruptly dorsally projected – is extended anteroposteriorly in the MCT/RJ P. ba. specimen, as in all recent taxa. So, this character is polymorphic or also results of a taphonomic outcome. As consequence, P. ba. lacks a suitable diagnosis. Our preliminary results revealed little differences in shape of P. ex. and P. ba. and a clear allometric effect in the shape variation. In conclusion, it seems reasonable to suggest that P. ba. is a junior synonym of P. ex., although we will wait to claim it after additional analyses.

Comparative analysis of shape variation in the cone scales of Larix dahurica and L. cajanderi (Pinaceae)

2021 ◽  
pp. 47-67
Author(s):  
Valentina P. Vetrova ◽  
◽  
Alexey P. Barchenkov ◽  
Nadezhda V. Sinelnikova ◽  
◽  
...  
Keyword(s):  
Discriminant Analysis ◽  
Geometric Morphometrics ◽  
Baikal Region ◽  
Canonical Discriminant Analysis ◽  
Shape Variation ◽  
Geometric Morphometric ◽  
The North ◽  
Larch Species ◽  
Geometric Morphometric Analysis ◽  
Cone Scale

Geometric morphometric analysis of shape variation in the cone scales of two closely related larch species, Larix dahurica Laws. (=Larix gmelinii (Rupr.) Rupr) and L. cajanderi Mayr, was carried out. The data on the taxonomy and distribution of L. dahurica and L. cajanderi are contradictory. The taxonomic status of L. cajanderi has been confirmed by the genetic and morphological studies performed in Russia and based on considerable evidence, but the species has not been recognized internationally, being considered as a synonym of Larix gmelinii var. gmelinii. In the systematics of larch, morphological characters of the generative organs are mainly used as diagnostic markers, among the most important being the shape variation of the cone scales. The aim of this study was to test geometric morphometrics as a tool for analyzing differentiation of L. dahurica and L. cajanderi in the shape of their cone scales. Characterization of shape variations in cone scales using geometric morphometric methods consists in digitizing points along an outline of scales followed by analysis of partial warps, describing individual differences in coordinates of the outline points. We studied the populations of L. dahurica from Evenkia and the Trans-Baikal region and six L. cajanderi populations from Yakutia and Magadan Oblast. In each population, we analyzed samples of 100-150 cones collected from 20-30 trees. Scales taken from the middle part of the cones were scanned using an Epson Perfection V500 Photo. On the scanned images, outline points were placed with a TPSDig program (Rolf, 2010), using angular algorithm (Oreshkova et al., 2015). The data were processed and analyzed using Integrated Morphometrics Programs (IMP) software (http://www.canisius.edu/~sheets/ morphsoft.html, Sheets, 2001), following the guidelines on geometric morphometrics in biology (Pavlinov, Mikeshina, 2002; Zelditch et al., 2004). Initial coordinates of the scale landmarks were aligned with the mean structure for L. dahurica and L. cajanderi cone scales using Procrustes superimposition in the CoordGen6 program. PCA based on covariances of partial warp scores was applied to reveal directions of variation in the shape of the cone scales. The relative deformations of the cone scales (PCA scores) were used as shape variables for statistical comparisons of these two larch species with canonical discriminant analysis. Morphotypes of the cone scales were distinguished in L. dahurica populations by pairwise comparison of samples from trees in the TwoGroup6h program using Bootstrap resampling-based Goodall’s F-test (Sheets, 2001). Samples from the trees in which the cone scales differed significantly (p < 0.01) were considered to belong to different morphotypes. Morphotypes distinguished in L. dahurica populations were compared with the morphotypes that we had previously determined in L. cajanderi populations. The composition and the frequency of occurrence of morphotypes were used to determine phenotypic distances between populations (Zhivotovskii, 1991). Multidimensional scaling matrix of the phenotypic distances was applied for ordination of larch populations. In this research, we revealed differentiation of L. dahurica and L. cajanderi using geometric morphometric analysis of the shape variation of cone scales. The results of PCA of partial warp scores exposed four principal components, which account for 90% of total explained variance in the shape of the cone scales in the two larch species. Graphical representations of these shape transformations in the vector form characterized directions of shape variability in scales corresponding to the maximum and minimum values of four principal components (See Fig. 2). PCA-ordination of the larch populations revealed some difference in the shape variation of the cone scales in L. dahurica and L. cajanderi (See Fig. 3). The results of canonical discriminant analysis of relative deformations of scales showed differentiation of the populations of the two larch species (See Fig. 4). Eleven morphotypes were identified in L. dahurica cones from Evenkia and nine morphotypes in the Ingoda population, three of the morphotypes being common for both populations (See Fig. 5). The shape of L. dahurica cone scales varied from spatulate to oval and their apical margins from weakly sinuate to distinctly sinuate. The Trans-Baikal population was dominated by scales with obtuse (truncate) and rounded apexes. The obtained morphotypes were compared with 25 cone scale morphotypes previously distinguished in the Yakut and the Magadan L. cajanderi populations (See Fig. 3). Four similar morphotypes of cone scales were revealed in the North-Yeniseisk population of L. dahurica and the Yakut populations of L. cajanderi. The differences between them in the populations of the two larch species were nonsignificant (p > 0.01). All morphotypes of cone scales from the Ingoda population of L. dahurica differed significantly from L. cajanderi cone scale morphotypes. The results of multidimensional scaling phenotypic distance matrix calculated based on the similarity of morphotypes of L. dahurica and L. cajanderi populations were consistent with the results of their differentiation based on relative deformations of scales obtained using canonical discriminant analysis (See Fig. 4 and Fig. 7). In spite of the differences in the shape of the cone scales between the North-Yeniseisk and the Trans-Baikal populations of L. dahurica, they both differed from L. cajanderi populations. Thus, phenotypic analysis confirmed differentiation of these two larch species. Despite the similarities between a number of morphotypes, the Yakut L. cajanderi populations were differentiated from L. dahurica populations. Significant differences were noted between intraspecific groups: between L. cajanderi populations from Okhotsk-Kolyma Upland and Yakutia and between L. dahurica populations from Evenkia and the Trans-Baikal region (See Fig. 4). The similarities between species and intraspecific differences may be attributed to the ongoing processes of hybridization and species formation in the region where the ranges of the larches overlap with the ranges of L. czekanowskii Szafer and L. dahurica×L. cajanderi hybrids. Geometric morphometrics can be used as an effective tool for analyzing differentiation of L. dahurica and L. cajanderi in the shape of their cone scales.

Sign in / Sign up

Export Citation Format

Share Document