Ventral Scales Research Articles

Bridging the gap: A new species of arboreal Abronia (Squamata: Anguidae) from the Northern Highlands of Chiapas, Mexico.

The mountain forests of Middle America are renowned for their endemic biodiversity, and arboreal alligator lizards (genus Abronia) are high-profile vertebrates endemic to this region. In this work, we describe a new species of arboreal Abronia that is known only from the type locality in the Northern Highlands of Chiapas, Mexico. The new species is diagnosed from all other members of the genus Abronia by the following combination of characters: lack of protuberant or spine-like supra-auricular scales, lack of protuberant or casque-like posterolateral head scales, dorsum of head pale yellow with distinct dark markings, 35-39 transverse dorsal scale rows, lateralmost row of ventral scales enlarged relative to adjacent medial row, and dorsum brown with darker crossbands that are sometimes reduced to rows of spots. We provisionally include the new species in the subgenus Lissabronia based on genomic and morphological evidence, but our results also suggest a close relationship to the subgenus Abaculabronia. The new species is geographically separated from the nearest Lissabronia and Abaculabronia species by the lowland Central Depression of Chiapas. Ongoing habitat loss and other factors imperil the new species, leading us to propose its listing under multiple threatened species frameworks. Because the Northern Highlands have poor coverage of protected areas, we briefly comment on the potential of this new species for stimulating conservation in the region.

A new species of Hemiphyllodactylus (Squamata, Gekkonidae) from southwest Yunnan, China.

A new species of gekkonid, Hemiphyllodactylusgengmaensissp. nov., is described based on six specimens from Gengma Dai and Wa Autonomous County, Yunnan, China. The new species can be distinguished from its congeners by a significant genetic divergence of greater than 9.7% in the mitochondrial ND2 gene and a combination of the following characters: a maximum SVL of 43.24mm; 8 or 9 chin scales; six circumnasal scales; 2 or 3 internasal scales; 9-11 supralabial scales; 8 or 9 infralabial scales; 11-18 dorsal scales; 8-10 ventral scales; a manual lamellar formula of 5-5-5-4 or 5-6-5-4 and a pedal lamellar formula of 5-5-6-5; 20-25 precloacal and femoral pore-bearing scales contiguous in males; dark postorbital stripes or striping on body; dark dorsal transverse blotches present; and a brown postsacral mark bearing anteriorly projecting arms. The discovery of this new species brings the number of Hemiphyllodactylus species in China to 15.

A New Species of <i>Cyrtodactylus</i> Gray, 1827 (Squamata, Gekkonidae), Previously Confused with <i>C. wayakonei</i> Nguyen, Kingsada, Rösler, Auer et Ziegler, 2010

A new species of the Cyrtodactylus chauquangensis species group is described from Yunnan Province, China, based on morphological and molecular data. The new species closely resembles C. wayakonei morphologically, but can be separated from the latter by having more white rings on original tail, more lamellae under finger IV and toe IV, less longitudinal ventral scale rows, and enlarged femoral scales. However, the new species is closely related to C. martini rather than C. wayakonei genetically. The new species differs from C. martini by genetic distance of 3.3% and from investigated other members of the C. chauquangensis species group by genetic distances of 6.4 – 17.8% in the COI gene.

A new species of Ninia (Serpentes, Colubridae) from western Ecuador and revalidation of N. schmidti

We describe a new species of Ninia Baird & Girard, 1853 endemic to the cloud forests of northwestern Ecuador. The new species has previously been confused with N. atrata (Hallowell, 1845) and N. teresitae (Angarita-Sierra and Lynch 2017) but is genetically most closely related to a third species of Ninia endemic to the Chocoan–Tumbesian transition area of western Ecuador. We revalidate the name N. schmidti (Jan, 1862), designate a neotype, and provide a diagnosis of the taxon and a description of its hemipenial morphology based on new material. The new and revalidated species can easily be identified from one another and from other trans-Andean South American Ninia based on ventral and subcaudal scale counts, hemipenial morphology, and coloration of the supralabials, throat, and belly. Finally, we remove N. atrata from the herpetofaunal list of Ecuador.

A NEW DWARF GECKO SPECIES (SQUAMATA: GEKKONIDAE: Cnemaspis) FROM THE NORTHERN WESTERN GHATS OF INDIA

Based on molecular and morphological data, I describe a new species of the polyphyletic gekkonid genus Cnemaspis Strauch, 1887 from the northern Western Ghats in India. The new species is the second smallest known Indian dwarf gekkonid and belongs to the clade of C. girii[i] sensu Pal [i]et al. (2021). It is genetically distinct from all congeners of the C. girii clade by p-distance ranging from 3.8 to 8.4 % on the 16S rRNA gene. Morphologically, the new species can be distinguished from all congeners by having the following combination of characters: A small species with adult males reaching a maximum SVL 27.0 mm; heterogeneous dorsal pholidosis with 11–12 longitudinal rows of enlarged tubercles; males with 3–4 femoral pores on each thigh, separated medially by 19–24 poreless scales; 63–65 middorsal scales; 136–150 ventral scales; 33–35 midbody scales; 12–14 subdigital lamellae under fourth digit of pes; feebly carinate scales on the neck and chest; and absence of conical or spine-like tubercles on flank.

Morphological identification of the whizzling sand snake: <i>Psammophis sibilans</i> in Zaria, Northwestern Nigeria

Background: Despite extensive research on snakes, although subject to some variation and ignored by many authors, scarce information is available on the morphology of Psammophis Sibilans.
 Objectives: This research aimed to study the morphological characterization of Psammophis Sibilans in Zaria, Northwestern Nigeria, as a basis for its morphological identification which may be extrapolated or used as baseline data to show the reliability of scale count in species determination of Psammophis Sibilans.
 Methods: Active capture methods were used on free-range snakes and scales were counted to distinguish between the families, generic and specific levels.
 Results: The result showed that on the head shield, the loreal [1.0±0.00], pre-nasal[2.0±0.00], internasal[2.0±0.00],preocular[4.0±0.00],supraocular[2.0±0.00],frontal[1.0±0.00], parietal[2.0±0.00] were all the same for all the population studied (n = 20). The dorsal scale [18.00±0.00], and anal plate [1.00±0.00] were also the same for all the snakes studied while the ventral scales [173±2.83], and tail scales [191.30±1.76] showed significant differences within the group. For the zoometric parameters, the body length [85.33±0.44], mid-circumference [7.40±0.10], head length [3.50±0.29], and tail length [32.17±0.17] all showed significant differences within and between the population except for the head width [1.00±0.00].
 In conclusion: The head shields are more reliable in the identification of Psamophis sibilans than the zoometric parameters studied, except for the head width. We also discovered a significant variation in the loreal head shield which was just one for all the population studied as opposed to studies from Egypt and Ethiopia where a range of one to two was reported.

Two sides of the same wing: ventral scales enhance dorsal wing color in the butterfly Speyeria mormonia.

Biological visual signals are often produced by complex interactions between light-absorbing and light-scattering structures, but for many signals potential interactions between different light-interacting components have yet to be tested. Butterfly wings, for example, are thin enough that their two sides may not be optically isolated. We tested if ventral wing scales of the Mormon fritillary Speyeria mormonia impact the appearances of dorsal orange patches, which are thought to be involved in sexual signaling. Using reflectance spectroscopy, we found ventral scales, either silvered or non-silvered, make dorsal orange patches significantly brighter, with the silvered scales having the greater effect. Computational modeling indicates both types of ventral scales enhance the chromatic perceptual signal of dorsal orange patches, with only the silvered scales also enhancing their achromatic perceptual signal. A lack of optical independence between the two sides of the wings of S. mormonia implies the wing surfaces of butterflies have intertwined signaling functions and evolutionary histories.

Two new karst-adapted species in the Cyrtodactyluspulchellus group (Reptilia, Gekkonidae) from southern Thailand.

The exploration of unsurveyed areas in southern Thailand discovered two new karst-adapted species, Cyrtodactylussungaiupesp. nov. and Cyrtodactyluswangkhramensissp. nov., from Thung Wa and La-ngu Districts, Satun Province, respectively. These new species are members of the C.pulchellus group that occur along the Thai-Malay Peninsula. The new species can be distinguished from all other congeners by their key morphological characters and genetic divergence. Morphologically, Cyrtodactylussungaiupesp. nov. and Cyrtodactyluswangkhramensissp. nov. can be diagnosed from other members by having a combination of differences in body size; degree of dorsal tuberculation; absence of tubercles on ventral surfaces; number of ventral scales, paravertebral tubercles and femoroprecloacal pores in males only; deep precloacal groove only in males; absence of a scattered pattern of white dorsal tubercles; number of dark body bands; and the extent of caudal tubercles on an original tail. Although the two species are sister taxa and have nearly identical morphologies, they are considered to be different species, based on a relatively high uncorrected pairwise genetic divergence of the mitochondrial ND2 gene (6.59-6.89%), statistically significant univariate and multivariate morphological differences (PERMANOVA and ANOVA) and diagnostic characteristics of caudal tuberculation on the original tail. Moreover, Cyrtodactylussungaiupesp. nov. and Cyrtodactyluswangkhramensissp. nov. are currently restricted to their karstic type localities which may serve as a geographic barrier to dispersal and gene flow.

A new species of Liolaemus (Iguania: Liolaemidae) from the hot deserts of northern Patagonia, Argentina

A new species of Liolaemus is described from southwest of the town of Añelo, Neuquén Province, Argentina. Integrative evidence methodology of external morphological characters and molecular phylogenetic analyses of mitochondrial DNA (cyt-b) is used to place the new species to the species group of Liolaemus boulengeri. The new species is phenotypically close to L. mapuche. The new Liolaemus is medium to large in size (males 77.64–83.98 mm, females 72.88–78.58 mm), with evident sexual dichromatism. Genetic distances of the mtDNA (cyt-b) between the new species and its closest relative species are greater than 3% (L. cuyanus 7.48–12.02%; L. josei 7.56–9.60%; L. puelche 8.23–9.93%; L. mapuche 8.51–9.79%). Molecular and morphological phylogenetic results show L. mapuche as the sister species of the new one. The new species is larger than L. mapuche. Dorsal and ventral scales are more numerous in the new species than in L. mapuche, precloacal pores in females are present in L. mapuche and absent in the new species. It has strict psammophilic habits, using sand mounds and sheltering, under Alpataco (Neltuma alpataco) bushes. The L. boulengeri group now contains 75 species distributed in Argentina, Bolivia, Brazil, Chile, Paraguay, Peru and Uruguay.

On the taxonomy of Uropeltis petersi (Beddome, 1878) (Serpentes: Uropeltidae) and description of a new, closely related species from the Western Ghats of India.

A new species of the uropeltid snake genus Uropeltis Cuvier, 1829 is described from the environs of Munnar in the Anamalai hils of the Western Ghats of peninsular India. Uropeltis tricuspida sp. nov. superficially resembles the poorly known and closely related U. petersi, but differs from that species in having more ventral and subcaudal scales, and a tri- rather than bicuspid posterior tip to the terminal scute.

A NEW SPECIES OF WATER SNAKE GENUS HYPSISCOPUS (SERPENTES: HOMALOPSIDAE) FROM SULAWESI, INDONESIA

We describe a new species of water snake genus Hypsiscopus that was formerly placed in the genus Enhydris from Towuti Lake, South Sulawesi, based on six specimens collected in 2003 and a specimen collected in 2019. The new species has several significant differences from other species in the genus Hypsiscopus (H. matannensis, H. plumbea, and H. murphyi) in possessing laterally compressed tail, higher number of scale rows in mid body, higher number of ventral scales, lower number of subcaudal scales, and distinct color pattern. The new species is likely distributed only in the Towuti Lake, and has higher level endemicity compared to H. matannensis. Further studies on the population and distribution are needed to evaluate its conservation status.

A new species of the Cyrtodactylusquadrivirgatus complex (Chordata, Reptilia, Squamata, Gekkonidae) from Sumatra Barat, Indonesia.

Among the six species of Cyrtodactylus occurring in Sumatra, two species were described based on non-Sumatran type series, C.consobrinus and C.quadrivirgatus. The latter species was described originally from Thailand thus the wider distribution in Sumatra should be clarified taxonomically. Cyrtodactylusquadrivirgatus from Sumatra Barat was examined using both morphology and the Natrium Dehydrogenase Subunit 2 (ND2) gene to clarify its taxonomic status and phylogenetic placement. It was found that these specimens form a sister clade to all other species of the sworderi group from Peninsular Malaysia and the genetic distance ranges from 20-24.3%. This subset is herein described as a new species. The new species is readily distinguished from C.quadrivirgatus and other Sumatran species by a combination of characters: small size SVL 37.5-53.78 mm; longitudinal rows of dorsal tubercles 16-19; paravertebral tubercles 31-41; ventral scales 32-43; 24-49 enlarged precloacal and femoral scales; precloacal pores rarely present; no precloacal depression; two postcloacal tubercles on each side; 14-19 subdigital lamellae on forth toe; 9-15 supralabial scales; 9-12 infralabial scales; three or four internasal scales; and 3-6 gular scales that border the first pair of postmental scales. This work underscores the importance of clarifying widely distributed species for taxonomic validation.

The discovery of two new species in the Cyrtodactylus irregularis group highlights that hidden diversity remains in the largest clade of the mega-diverse genus Cyrtodactylus

The Cyrtodactylus irregularis group, originally considered to consist of only one taxon, has been split into 26 species. We herein present the distribution of all species within the group in Cambodia, Laos and Vietnam and describe two new species based on integrative analyses. Cyrtodactylus chumuensis sp. nov. is discovered from Dak Lak Province and distinguished from the remaining taxa by more than 11.86% genetic divergence and by the following distinct morphological characters: size medium (SVL 67.5 mm); enlarged femoral scales on each thigh 4–5, femoral pores 0–2 in males; precloacal pores 6–7 in males; ventral scale rows 43–45; lamellae under toe IV 17–21. Cyrtodactylus arndti sp. nov. is described from Binh Dinh Province and genetically differentiated from its congeners by a minimum of 11.42% and by the following characters: adult size medium (SVL 73.4–80.8 mm); enlarged femoral scales on each thigh 5–11; femoral pores 0–2 in males; 6 precloacal pores in males, females with 6 pitted precloacal pores; ventral scale rows 26–38; lamellae under toe IV 17–22; subcaudal scales transversely enlarged. Additionally, we highlight the potential cryptic diversity with the taxon currently regarded as C. pseudoquadrivirgatus and understudied areas in Vietnam where new species will likely be discovered.

Somitic positional information guides self-organized patterning of snake scales.

Two influential concepts in tissue patterning are Wolpert's positional information and Turing's self-organized reaction-diffusion (RD). The latter establishes the patterning of hair and feathers. Here, our morphological, genetic, and functional-by CRISPR-Cas9-mediated gene disruption-characterization of wild-type versus "scaleless" snakes reveals that the near-perfect hexagonal pattern of snake scales is established through interactions between RD in the skin and somitic positional information. First, we show that ventral scale development is guided by hypaxial somites and, second, that ventral scales and epaxial somites guide the sequential RD patterning of the dorsolateral scales. The RD intrinsic length scale evolved to match somite periodicity, ensuring the alignment of ribs and scales, both of which play a critical role in snake locomotion.

An expanded description of Cnemaspis gracilis (Beddome 1870) (Squamata: Gekkonidae) based on recent material.

Cnemaspis gracilis is a poorly known species that has been reported from across southern India, with 11 named species within the clade. The species is known only from the type series, as many other records from areas outside the type locality have turned out to represent distinct species. We provide an expanded morphological description of the species based on topotypic material and other samples that were assigned using genetic data. Cnemaspis gracilis is now known with certainty from three localities in the vicinity of Palakkad, Palakkad District, Kerala, and Valparai town, Coimbatore district, Tamil Nadu, besides from an introduced population in the Timber Market, Kolhapur city, Kolhapur district, Maharashtra, India. The species is 7.6-15.8 % divergent on the ND2 gene from described members of the gracilis clade and can be diagnosed by a combination of morphological characters including body size, number of paravertebral tubercles between limb insertions, number of dorsal tubercle rows, number of ventral scale rows across the belly, number of femoral and precloacal pores and poreless scales separating these series in males, and the presence of a single central black ocellus on the neck and a smaller one on the occiput. The assignment of extant populations to the species, a detailed morphological description and genetic data will allow the description of many more species from within this diverse clade of diurnal geckos.

Hemidactylus paucifasciatus (Squamata: Gekkonidae), a new species of large-bodied, tuberculate gecko from Northern Odisha, India.

A new Hemidactylus belonging to the H. prashadi group is described herein, based on a series of four specimens from the Chota Nagpur Plateau in northern Odisha. Hemidactylus paucifasciatus sp. nov. can be diagnosed from regional congeners by its large body size (SVL up to 117.7 mm), the number of dorsal tubercle rows at mid-body, three or four bands on the dorsum, the number of enlarged tubercles in paravertebral rows, the number of femoral pores and poreless scales separating the left and right series on the femoral-precloacal row in males, and the number of ventral scales across the belly at mid-body. A mitochondrial phylogeny demonstrates that the new species is nested within the H. triedrus complex of the northern clade within the H. prashadi group, with 16.2-16.5 % pairwise divergence in ND2 sequence data from members of the H. triedrus complex and > 21 % from other members of the prashadi group. Hemidactylus paucifasciatus sp. nov. is the first endemic gecko to be described from the Chota Nagpur Plateau.

Integrative taxonomy provides evidence for a cryptic lineage in the velvet worm Peripatopsis birgeri species complex (Onychophora: Peripatopsidae) in KwaZulu-Natal, South Africa

During the present study, species boundaries in the velvet worm Peripatopsis birgeri species complex in KwaZulu-Natal, South Africa, were examined with the use of DNA sequence data, gross morphology, scanning electron microscopy (SEM) and ecological niche modelling. Mitochondrial CO1 and nuclear 18S rRNA sequence data were used to generate a phylogeny using both a Bayesian inference and maximum likelihood approaches. Both the CO1 sequence data and the combined DNA sequence topology (CO1 + 18S rRNA) revealed the presence of two geographically distinct clades within the P. birgeri species complex. Results from three species delimitation methods (GMYC, PTP and ASAP), were incongruent in determining the number of species within the species complex and generally overestimated the number of operational taxonomic units. The latter result can be attributed to the marked genetic structure within the species complex, a result corroborated by the CO1 haplotype network and statistically significant F ST values. Divergence time estimation suggests that the two clades diverged during the Plio/Pleistocene. Niche modelling revealed that the two clades were differentially impacted by bioclimatic variables and occupied different habitats. Gross morphological characteristics, such as leg pair numbers and colour revealed no fixed differences between the two clades, however, a creamy white headband/collar occurred exclusively in specimens of clade 1 (P. birgeri). In contrast, SEM revealed fixed dorsal and ventral scale rank differences between the two clades. The results corroborate the presence of a novel species within the P. birgeri s.s. species complex. Peripatopsis birgeri s.s. is revised and restricted to the southern Drakensberg and a new species, P. polychroma sp. nov. (clade 2), from the northern Drakensberg and adjacent Afrotemperate forests in the interior of KwaZulu-Natal is described. https://zoobank.org/urn:lsid:zoobank:org:pub:569557AB-8BC8-49B6-B8AA-96507371297B

Friction measurement of modified Polydimethylsiloxane(PDMS) surfaces inspired by Malayopython Reticulatus

The lack of limbs on snakes enables its ventral scales to be in almost constant contact with the substrate. Their skin is presumably adapted to generate high and low friction to slither. This frictional characteristics in snakes were hypothesized to be contributed by the be tooth-shaped or denticle-like microstructures found on the snake ventral scales. The frictional properties of the microstructures found on snake ventral scales was studied and its feasibility as an inspiration for surface modifications was observed. This study was carried out to analyze the frictional anisotropy exhibit by the snake ventral scale microstructures and also how it changes the frictional properties of the PDMS surface when the microstructures are replicated on to it. The PDMS embedded-elastomeric stamping method was used in this experiment to replicate the snake ventral scales onto the PDMS. Based on the data collected the microstructures on the snake ventral scales does exhibit frictional anisotropy. The PDMS with replicated snakeskin microstructures displays higher COF compared to PDMS with smooth surface. When sliding on most types of surfaces, the COF of real snakeskin and replicated snakeskin is higher if the surface is semi wet. Whereas for smooth PDMS the COF is lower when the surfaces are semi wet. Generally, from both experiments, when the replicated snakeskin is sliding on the surface in the lateral direction, it is observed that the COF is the lowest followed by the caudal then the rostral direction.

Resurrection of Pareas yunnanensis (Vogt, 1922) with description of a new species of Pareas from Yunnan Province, China (Squamata, Pareidae)

Based on molecular and morphological data of four specimens of Pareas Wagler, 1830 collected from the type locality of P. yunnanensis (Vogt, 1922), along with examination of the type specimens of P. yunnanensis, we revalidate this poorly known, secretive species. Furthermore, based on molecular and morphological lines of evidence we also describe a new species of Pareas from Xishuangbanna Prefecture, Yunnan Province, China. Morphologically, the new species closely resembles its sister species P. nigriceps Guo & Deng, 2009. However, the new species is divergent from the latter in cytochrome b mtDNA gene sequences, and can be distinguished from all congeners by the following combination of morphological characteristics: single preocular, postocular fused with subocular, loreal not bordering orbit, vertebral scales enlarged, 3–5 rows of mid-dorsal scales keeled at the middle of the body, ventral scales 160–171; subcaudals 62–64, dorsal surface of head solid black or reddish-brown, dark nuchal band present, iris brownish-black or reddish-brown.

The taxonomic status of the kukri snake Oligodon arenarius Vassilieva, 2015 with a redescription of Oligodon macrurus (Angel, 1927) (Squamata, Serpentes, Colubridae)

We investigated the taxonomic status of the recently described kukri snakeOligodon arenariusVassilieva, 2015 and the morphologically similarOligodon macrurus(Angel, 1927), two species endemic to the southern coast of Vietnam. Based on phylogenetic analyses using three mitochondrial genes (12S–16S rRNA, cytochromeb), we recoveredO. arenariusandO. macrurusin a clade within theO. cyclurus-taeniatusspecies group, agreeing with previous intrageneric classifications. Genetic distances betweenO. arenariusandO. macrurusare extremely low (less than 0.5% based on 12S–16S) and renderO. arenariusparaphyletic. All preserved specimens ofO. arenariusandO. macrurusconvey 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 synonymizeO. arenariuswithO. macrurus. We provide a formal redescription ofO. macrurus, designate a neotype specimen to avoid future taxonomic confusion, and provide the first detailed osteological description of this species.Oligodon macrurussensu 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 thatO. macrurusshould be listed as “Vulnerable” based on the assessment criteria of the International Union for Conservation of Nature (IUCN).