DOI: 10.3897/vz.76.e169219

Authors: Diego Omar Di Pietro, Julieta Sánchez, Sebastián Poljak, Leandro Alcalde

Abstract: We analysed the genetic and morphological variation in Philodryas patagoniensis, a widely distributed South American racer snake. Two well-differentiated haplogroups were identified using mitochondrial gene sequences (12S and 16S) and the nuclear gene c-mos. Genetic divergence between these haplogroups correlates strongly with morphological differences, allowing the recognition of two morphotypes within P. patagoniensis. We integrated genetic and morphological data into a total evidence analysis using parsimony. Our results support the distinction between the two haplogroups/morphotypes, consistent with recognising two species within P. patagoniensis. Accordingly, we re-describe P. patagoniensis, refining its morphological variation and geographical distribution to reflect the observed genetic differentiation, and describe a new species. Morphological characteristics can distinguish the two species, including body measurements, scale patterns, and cranial osteology. The new species differs from P. patagoniensis sensu stricto in traits associated with arboreal habits, which are strongly correlated with the distribution of the two taxa across forested and open habitats in South America. Furthermore, P. patagoniensis sensu stricto has a significant Lycosa spider component in its diet, which is absent in the newly described species.

HTML

XML

PDF

DOI: 10.3897/vz.74.e123485

Authors: Evgeniy Simonov, Artem Lisachov, Spartak Litvinchuk, Anastasia Klenina, Polina Chernigova, Alexander Ruchin, Andrey Bakiev, Kazhmurat Akhmedenov

Abstract: Abstract Most of the geographic range of the grass snake Natrix natrix is occupied by the subspecies N. n. scutata, which occurs from Eastern Europe to East Siberia. This study addressed the phylogeography of this subspecies via analysis of variation of partial cytochrome b (cyt b) sequences from 135 individuals sampled at 91 localities across its range, in addition to species distribution modelling. A haplotype network was constructed and identified a major star-like haplogroup that harbours most of the analysed specimens and is considered the main source of recolonisation of vast territories of northern Eurasia after the Last Glacial Maximum (LGM). Most of this subspecies’ current range is occupied by haplotypes from a single haplogroup, with probable refugia in the south of the European part of Russia or the North Caucasus. The most frequent (ancestral) haplotype in this group is the only one discovered in West Siberia among 25 specimens from 13 sampling sites, indicating relatively recent colonisation of Siberia. According to species distribution modelling, no relatively suitable areas were present in Central Asia or Siberia during the LGM. Nonetheless, the only two specimens examined from the easternmost area of the species’ geographic range, near Lake Baikal, had unique haplotypes that differed from the most common haplotype by one and two substitutions. The most probable explanation for this pattern is that N. n. scutata colonised the area during a previous interglacial period and survived here during the last glacial. The Mugodzhar Range in western Kazakhstan also showed cyt b differentiation as compared to surrounding areas but warrants further sampling to test competing hypotheses.

HTML

XML

PDF

DOI: 10.3897/vz.74.e123824

Authors: Simona Papežíková, Martin Ivanov, Petr Papežík, Adam Javorčík, Konrad Mebert, Daniel Jablonski

Abstract: Abstract The Western Palearctic harbours a diverse snake fauna, including numerous endemic species and yet unnamed clades, identified through molecular analyses. However, morphological characteristics of these clades, even of common species, often remain relatively unexplored. In this study, we provide an examination of the morphology and cranial anatomy of the semi-aquatic snake species Natrix tessellata (Laurenti, 1768), with a focus on populations of the so-called ‘Europe’ and ‘Greece’ clades. Utilising both museum collections and field data, we first morphologically examined 541 individuals of N. tessellata, categorising them according to previously established clades and lineages that resulted in relatively low morphometric and meristic variation across the species’ range. When assessing the 448 specimens from the ‘Europe’ and the ‘Greece’ clades separately, we similarly observed little variation in meristic characteristics. On the other hand, individuals of the ‘Greece’ clade displayed smaller and more slender body and head proportions compared to those of the ‘Europe’ clade and the pigmentation of the labial scales is distinctively paler in the ‘Greece’ clade, whereas the overall body colouration remains largely similar between the two. Our osteological analysis of 47 N. tessellata skulls also indicated slight differences in the frontoparietal portion of the braincase between the ‘Europe’ and the ‘Greece’ clades, warranting further examination with a larger dataset and extending to other skull components. These findings hold significance for ongoing enquiries into the species’ biogeography, morphology and ecological adaptations. In summary, the integration of morphological and osteological data with genetic information offers a promising avenue for potential taxonomic revisions of N. tessellata in the future.

HTML

XML

PDF

DOI: 10.3897/vz.74.e112132

Authors: Parinya Pawangkhanant, Nikolay A. Poyarkov, Harry Ward-Smith, Rupert Grassby-Lewis, Montri Sumontha, Nikita S. Kliukin, Sabira S. Idiiatullina, Alexei V. Trofimets, Chatmongkon Suwannapoom, Justin L. Lee

Abstract: Abstract We describe a new species of kukri snake (Oligodon Fitzinger, 1826) from the limestone karst formations of Satun and Trang Provinces in southern Thailand. Phylogenetic analyses based on three mitochondrial DNA fragments (12S–16S ribosomal rRNA and cytochrome b) recover the new species within the Oligodon cinereus species complex, where it forms a deeply divergent yet poorly supported clade sister to Oligodon saiyok Sumontha et al., 2017 and another unnamed lineage currently referred to Oligodon cinereus (Günther, 1864) from southwest Myanmar. Morphologically, the new species is distinguished from all other members of the genus by the following combination of characters: ventral scales 189–193 with distinct lateral keeling; subcaudal scales 47–54, paired; anterior dorsal scale rows 17–19, with the reduction from 19 to 17 rows occurring above the 28th–30th ventral scale when present; maxillary teeth 8, blade-like and laterally compressed; dorsum olive–gray, plain; ventral surface white anteriorly, dark gray posteriorly; underside of tail dark gray, smeared with white. We briefly discuss the natural history and conservation status of this new species and provide observations of other kukri snakes inhabiting limestone karst habitats. Our study also incorporates genetic samples of four recently described Oligodon endemic to Thailand, all of which are recovered in the O. cinereus species complex. In agreement with previous studies, we demonstrate that species-level diversity within the O. cinereus species complex is underestimated, and additional sampling is necessary to revise this taxonomically challenging clade.

HTML

XML

PDF

DOI: 10.3897/vz.74.e106238

Authors: Vinícius Sudré, Albedi Andrade-Junior, Manuella Folly, Josué A. R. Azevedo, Robson Waldemar Ávila, Felipe Franco Curcio, Pedro M. Sales Nunes, Paulo Passos

Abstract: Abstract Currently, the proposed diagnoses for the Chironius bicarinatus complex reflect a wide variation in color pattern and pholidosis. Herein, we review the Chironius bicarinatus complex based on morphological and molecular data from a sample of 485 specimens covering the species distribution. Our results corroborate the recognition of C. bicarinatus and C. gouveai, and diagnose a distinct lineage without an available name. Thus, here we describe this new species restricted to the Baturité Massif, a relictual rainforest isolated in the Caatinga xerophytic domain, in the state of Ceará, northeastern Brazil. The new species can be distinguished from its congeners by its unique combination of qualitative and quantitative morphological characters (scale counts, morphometric, color pattern), and is also supported by molecular and ecological evidence. Additionally, we rectify data on the distribution and morphological variability of C. gouveai to accurately infer the boundaries between this taxon and C. bicarinatus, which was not properly addressed. Finally, we discuss our results in the light of previous studies that suggest diversification hypotheses in the Atlantic Forest already detected for other taxa, highlighting the importance of conserving the areas of “Brejos de Altitude”, in northeastern Brazil, and the southern limit of Serra do Mar up to Serra do Tabuleiro, in southern Brazil.

HTML

XML

PDF

DOI: 10.3897/vz.73.e103319

Authors: Uwe Fritz, L. Lee Grismer, Marika Asztalos

Abstract: Using georeferenced photographic records of 2944 grass snakes from Germany, Austria, and northern Italy as well as previously published mtDNA sequences (n = 1062) and microsatellite data (n = 952) for grass snakes from the same regions, we examined whether or not coloration and pattern reliably allow to differentiate between Natrix natrix and N. helvetica and if so, whether the distribution patterns revealed by phenotypes and genetics are congruent. Furthermore, we used cline analyses across hybrid zones to test whether the phenotypic transition from one species to the other parallels the steep clines unveiled by genetics. Our results suggest that the two species can be reliably differentiated using coloration and pattern. The most powerful diagnostic traits are the presence/absence of side bars on the body flanks, the number of occipital spots, and the shape of the posterior dark occipital spot. The distributions of morphologically identified N. natrix and N. helvetica match their genetically confirmed ranges. Single conflicting individuals morphologically identified as N. natrix or hybrids within the distribution range of N. helvetica either represent misidentifications or translocated snakes. For the genetic markers and phenotypes, our cline analyses revealed concordant steep clines across hybrid zones. However, the southern part of the hybrid zone in Italy, for which no sufficient genetic data are available, should be studied in more detail because the phenotypic data suggest a smooth cline in this region. The unexpected high percentage of putative hybrids with dorsal stripes in this region also calls for further research. For northwestern Germany, another region for which no genetically verified records are available, iNaturalist data suggest that the contact zone of N. natrix and N. helvetica is near the Ems River and extends from there southeastwards to the region of Höxter, North Rhine-Westphalia.

HTML

XML

PDF

DOI: 10.3897/vz.73.e96958

Authors: Platon V. Yushchenko, Justin L. Lee, Hieu Minh Pham, Peter Geissler, Elena V. Syromyatnikova, Nikolay A. Poyarkov Jr.

Abstract: We investigated the taxonomic status of the recently described kukri snake Oligodon arenarius Vassilieva, 2015 and the morphologically similar Oligodon macrurus (Angel, 1927), two species endemic to the southern coast of Vietnam. Based on phylogenetic analyses using three mitochondrial genes (12S–16S rRNA, cytochrome b), we recovered O. arenarius and O. macrurus in a clade within the O. cyclurus-taeniatus species group, agreeing with previous intrageneric classifications. Genetic distances between O. arenarius and O. macrurus are extremely low (less than 0.5% based on 12S–16S) and render O. arenarius paraphyletic. All preserved specimens of O. arenarius and O. macrurus convey little to no differences in color pattern, hemipenial morphology and osteological features; the latter of which is based on three dimensional micro computer tomography (µCT) scans of one specimen per species. Contrasting these results, univariate and multivariate analyses revealed significant differences in relative tail length, and the number of ventral and subcaudal scales between both species. Although the molecular and morphological datasets present conflicting results, integrating the evidence leads us to synonymize O. arenarius with O. macrurus. We provide a formal redescription of O. macrurus, designate a neotype specimen to avoid future taxonomic confusion, and provide the first detailed osteological description of this species. Oligodon macrurus sensu stricto is endemic to coastal dunefields and adjacent forest habitats in southern Vietnam, where ongoing human development, tourism and road mortality pose significant threats to its conservation. Consequently, we suggest that O. macrurus should be listed as “Vulnerable” based on the assessment criteria of the International Union for Conservation of Nature (IUCN).

HTML

XML

PDF

DOI: 10.3897/vz.73.e91230

Authors: Platon V. Yushchenko, Justin L. Lee, Thy Neang, Hun Seiha, Nguyen Van Tan, Gernot Vogel, Nikolay A. Poyarkov Jr.

Abstract: The ashy kukri snake Oligodon cinereus (Günther, 1864) is a widely distributed and morphologically variable species found throughout mainland Southeast Asia. In this paper, we re-assessed the taxonomic status of O. cinereus populations found in southern Indochina (southern Vietnam, Cambodia, and southern Laos), including the recently described Cat Tien kukri snake Oligodon cattienensis Vassilieva et al., 2013, which was previously confused with this species. Phylogenetic analyses using mitochondrial DNA from the 12S–16S ribosomal subunit and cytochrome b gene revealed that O. cattienensis is embedded in a mixed clade containing samples of the subspecies O. cinereus pallidocinctus, which bears a dorsal color pattern with white crossbars and black edges. This clade forms a strongly supported sister group with a topotypic sample of O. cinereus cinereus, representing populations bearing a uniform dorsal color pattern and slight reticulate markings, however the genetic divergence between the two clades is very low. The morphological characters used to distinguish O. cattienensis from O. cinereus sensu lato broadly overlap and supposed differences in hemipenial morphology between the two taxa are due to outdated terminologies used to describe the organ. We relegate both O. cattienensis and O. cinereus pallidocinctus to the junior synonymy of O. cinereus and consider all color patterns of this species found near the type locality in Cambodia, southern Laos, and southern Vietnam to represent O. cinereus sensu stricto. Future integrative investigations across the range of O. cinereus sensu lato are needed to resolve the status of the remaining subspecies and synonyms associated with this taxon. Problems associated with hemipenial morphology and Oligodon systematics are also discussed.

HTML

XML

PDF

DOI: 10.3897/vz.72.e87426

Authors: Uwe Fritz, Flora Ihlow

Abstract: Abstract We used a dataset of georeferenced photos of 5,751 grass snakes from iNaturalist to evaluate subspecific variation of Natrix natrix in coloration and pattern. Our results provide evidence that all four genetically delineated subspecies differ morphologically, although unstriped individuals of N. n. vulgaris are difficult to tell apart from the nominotypical subspecies. The iNaturalist dataset shows that the frequency of dark body coloration increases from south to north and from west to east. This trend is both concordant with taxonomic variation (the easternmost subspecies, N. n. scutata, being the darkest taxon) and variation within the same subspecies (in N. n. natrix and N. n. scutata more northern populations harbor more dark or melanistic individuals than more southern populations). Although available characters were limited to coloration and pattern traits, our study suggests that photo material from iNaturalist and similar platforms can be a valuable data source for studies on morphological variation. However, investigations using such databases can only supplement, but not replace, studies using museum material because only then measureable, meristic and genetic characters will be accessible.

HTML

XML

PDF

DOI: 10.3897/vz.72.e84516

Authors: Ho Yuen Yeung, Michael W. N. Lau, Jian-Huan Yang

Abstract: A new species of the genus Calamaria Boie, 1827, Calamaria arcana sp. nov., is described based on a single male specimen collected from Mt. Dadongshan, Guangdong, southern China. The new species can be distinguished from all known congeners by the significant genetic divergence in the mitochondrial cytochrome-b gene fragment (p-distance ≥ 13.9%), and morphologically by the combination of the following characters: (1) ten modified maxillary teeth; (2) four supralabials, second and third supralabials entering orbit; (3) preocular present; (4) mental not touching anterior chin shields; (5) six scales and shields surrounding the paraparietal; (6) 170 ventral scales; (7) 22 paired subcaudals; (8) tail not gradually tapering, abruptly tapering at the tip; (9) dorsal scales reduced to five rows above last subcaudal at tail; (10) dorsum of body and tail brownish; (11) dark collar on nuchal region absent; (12) two outermost dorsal scale rows light yellow with upper margins partly dark pigmented; (13) ventral scales immaculate, without dark outermost corners and pigmentation anteriorly; and (14) absence of distinct dark longitudinal line or scattered spots on the underside of tail. Calamaria arcana sp. nov., represents the fifth species of the genus recorded in China. Following the IUCN Red List Categories and Criteria, we propose the new species to be listed as Data Deficient.

HTML

XML

PDF