Trachischium lalremsangai: A new species of Worm-eating Snake from Mizoram State, India, and Chin State, Myanmar.

Members of the Natricid Snake genus Trachischium are commonly known as Slender Snakes or Worm-eating Snakes. They are fossorial in nature (live underground in burrows) and are distributed in the montane forests of India, Nepal, Bhutan, China, Myanmar, and Bangladesh, typically at altitudes of between 800 and 2500 m above sealevel. Their lifestyle and habitat makes studying (or indeed finding) them difficult, and they are subsequently one of the least well known groups of Snakes. The genus Trachischium currently contains ten species, including two which were previously assigned to the genus Blythia; the two genera having been merged in 2024 on the basis that their defining criteria overlapped.

In a paper published in the journal Herpetozoa on 19 May 2026, Virender Bhardwaj, Amit Bal, and Chhangte Tluanga of the Developmental Biology and Herpetology Laboratory at Mizoram University, and Zeeshan Mirza of the Max Planck Institute for Biology, describe a new species of Trachischium from Mizoram State, India, and Chin State, Myanmar.

The new species is described on the basis of a specimen collected by Bhardwaj et al. in the Murlen National Park in 2025. A second specimen, which was collected in Chin State, Myanmar, in 2003, and now sits in the collection of the California Academy of Sciences, where it has been classified as Blythia reticulata (a species currently reassigned to Trachischium as Trachischium reticulata) on the basis of a scale pattern and colouration which matches the new species, but is atypical for Trachischium reticulata. 

Bhardwaj et al. name the new species Trachischium lalremsanga, in honour of Hmar Tlawmte Lalremsanga of Mizoram University for his contributions to herpetology in Northeast India, his guidance to numerous students, and his facilitation of research throughout the region and the Indo-Burma Biodiversity Hotspot. The species is described from two specimens, both male, one 409 mm in length and the other 506 mm, which makes it one of the larger species of Worm-eating Snakes. The dorsal surface of these Snakes is dark brown with a lustrous blue iridescence throughout, the front quarter of the ventral surface is a creamy white, the remainder brown with white speckles.

Trachischium lalremsangai, holotype male, MZMU 3757, in life. Bhardwaj et al. (2026).

The specimen Bhardwaj et al. collected was found moving along a road, close to the village of Murlen on the fringe of the Murlen National Park, 1560 m above sealevel, at about 9.30 in the evening, and shortly before a period of rain. This area forms part of the India-Burma Biodiversity Hotspot, and contains a mixture of tropical, semi-evergreen, and montane forests, with a dense canopy cover. Annual rainfall varies between about 2500 mm and about 3000 m, and the temperature varies between about 5°C in the winter and about 35°C in the winter. The area where the Snake was found has a diverse vegetation, including Oaks, Quercus spp., Needlewood, Schima wallichii, Birches, Betula spp., Champak, Michelia champaca, Khasi Pines, Pinus khasiana, Cherries, Prunus spp., Bayberry, Myrica spp., Rhododendrons, Rhododendron spp., dense stands of Thorny Bamboo, Arundinaria callosa, Cane Grasses, and a rich array of Orchids. The specimen collected in Myanmar was found at a site about 90 km away in a straight line, with a similar environment. Based upon this, Bhardwaj et al. estimate that the species may be present across northeast Mizoram and adjoining Manipur in India, as well as within the similar elevation realms of the Chin Hills.

The phylogeny of the genus Trachischium is still somewhat uncertain, and in need of thorough revision. Many species are described from single specimens, with only vague locations recorded. The genus is found from Jammu and Kashmir in the west to Arunachal Pradesh in the east, south as far as northern Myanmar and north as far as Tibet. At least one widely distributed species, Trachischium fuscum, is likely to be a species complex (group of closely related, yet reproductively isolated, and similar-appearing species). The genus Blythia was incorporated into the genus Trachischium as a junior synonym in 2024, yet this group of Snakes remain distinctive in appearance and this may be revised again; it is to this Blythia-group that the new species, Trachischium lalremsanga, belongs. Genetic data is available for only a single specimen of many species.

With this in mind, Bhardwaj et al. carried out a phylogenetic analysis for Trachischium lalremsanga using the mitochondrial 16S rRNA and cytochrome b genes and the nuclear oocyte maturation factor mos and recombination activating gene 1 genes, and comparing these to publicly available sequences from the GenBank database. 

This analysis found that the genus Trachischium can be split into three distinct subgroupings, which Bhardwaj et al. refer to as Clade 1, Clade 2 (which corresponds to the Blythia-group), and Clade 3. Clade 2 and Clade 3 are more closely related to one-another than either is to Clade 1, which forms an outgroup, so while Clade 2 could potentially be taken out of the genus Trachischium and returned to its original name, this would also require the renaming of Clade 3, with the designation Trachischium limited to Clade 1, which contains the type species for the genus, Trachischium fuscum (a type species is the species which defines a genus; other species are determined to belong or not belong to the genus on the basis of how closely they are related to that genus).

Maximum likelihood phylogeny based on concatenated two nuclear (c-mos and RAG-1) and two mitochondrial (16S and cyt b) genes of selected Natricine Snakes showing relationships within the genera Trachischium and Blythia. Numbers at nodes show maximum likelihood clade support. The new species from Murlen National Park is highlighted in red text. Bhardwaj et al. (2026).

See also...

Assessing the impact of predation on birth size in marine Snakes.

Moving from one environment to another exposes organisms to new selective pressures on life histories, and where multiple organisms from related lineages make the same transition, it presents an opportunity for biologists to analyse these pressures. For example, Squamates (Snakes and Lizards) which migrate from warm environments to cooler ones frequently switch from egg-laying to bearing live young, while Birds making the same transition tend to produce smaller clutches of eggs.

Birth size is considered to be a fundamental life-history trait, subject to a number of evolutionary pressures. Where intraspecific competition is low, smaller birth sizes are often a result, as offspring survival is not dependent on size at birth. Conversely, larger birth size can be driven by a number of factors, for example a lack of small prey can drive up birth size in species where the young must hunt for themselves, as only larger neonates are able to capture enough prey to survive. 

The shift from a terrestrial habitat to a marine one presents organisms with a variety of different challenges, including thermal regimes, oxygen availability, light levels, ocean currents, types of predators, prey, competitors and pathogens. Nevertheless, the marine environment clearly presents opportunities for terrestrial Tetrapods, with numerous lineages of Mammals, Reptiles, and even Birds having made the transition. Elapid (Front-fanged) Snakes have made this transition at least three times, with the Sea Kraits, Laticaudinae, having split from terrestrial relatives in Asia about 16 million years ago, while at least two lineages within the Australian subfamily Hydrophiinae (together referred to as Sea Snakes) switched to a marine habit more recently. The three lineages show convergent evolution for a number of traits, including the development of laterally compressed bodies with paddle-like tails, the appearance of salt-excreting glands, and common life-history traits. A fourth group of (non-Elapid) Snakes, the Acrochordidae, are semi-aquatic, and often semi-marine in habit, and show some of these traits.

Marine Snakes typically produce fewer young than terrestrial Snakes, which has been linked to a need for gravid females to retain a hydrodynamic shape. Nevertheless, the offspring are typically larger at birth than those of their terrestrial relatives, which would seem to work against this.

In a paper published in the journal Royal Society Open Science on 13 December 2023, Richard Shine of the School of Natural Sciences at Macquarie University, Shai Meiri of the School of Zoology and Steinhardt Museum of Natural History at Tel-Aviv University, Terri Shine and Gregory Brown, also of the School of Natural Sciences at Macquarie University, and Claire Goiran of LabEx Corail and  Institut de sciences exactes et appliquées at the Université de la Nouvelle-Calédonie, examine the possibility that size-selective predation on young Snakes could be the driver of increased neonatal size in Marine Snakes.

Smaller terrestrial Snakes are known to be vulnerable to a wider range of predators than larger Snakes, with many predators targeting smaller Snakes while actively avoiding larger ones. However, predation rates on smaller Snakes can be lower than on larger individuals, due to the ability of small Snakes to remain inactive in well-hidden retreats.

Marine Snakes are less able to do this, as they must ascend to the surface to breath. This means that Snakes must leave their protective shelters and cross open water, where they are vulnerable to predation, several times per day. Predation of Snakes by large Fish during these crossings is well-documented, supporting the hypothesis that this is a risky endeavour for marine Snakes.

In order to test the hypothesis, Shine et al. first examined records of birth sizes in both marine and terrestrial Snakes, to confirm that the perceived trend was in fact real, then carried out experimental trials with model Snakes of different sizes to see if smaller Snakes were in fact more vulnerable to predation.

Shine et al. obtained data on hatchling and neonate sizes (Snakes can lay eggs or bear live young, but this does not appear to affect infant size much) and snout-vent lengths of adult females of 166 species of terrestrial, semi-aquatic, and marine Snakes, from published literature and the collection of the Steinhardt Museum. Semi-aquatic Snakes were found to produce slightly smaller offspring than terrestrial Snakes on average. However, the sample size for these Snakes was very small, and the subject was not investigated further. The adult snout-vent length for female Snakes in the study averaged at 800 mm, with the offspring of terrestrial Snakes having an average length of 200 mm, and the average length of new-born marine Snakes being 300 mm. 

Based upon this, Shine et al. hypothesised that a 200 mm Snake would be at significantly higher risk of predation in a typical marine Snake environment than a 300 mm Snake. To test this, an experiment was devised in which commercially available fibreglass fishing lures designed to resemble Snakes had their hooks removed and additional weights added to ensure they retained negative buoyancy, and were painted black to resemble the most common colour morph of the locally abundant Turtlehead Sea Snake, Emydocephalus  annulatus. These were then dragged by a snorkeler, Claire Goiran, over Coral reefs off the island of Ile aux Canards in New Caledonia, while a second snorkeler, Richard Shine, followed and recorded the reaction of large predatory Fish to the lures. 

A Camouflage Grouper, Epinephelus polyphekadion, following a black Snake-shaped lure, immediately prior to launching an attack. Teri Shine in Shine et al. (2023).

During 47 trials, Shine et al. recorded 114 responses. These included 38 attacks, and 76 encounters in which Fish followed the lure but did not attack. The size of the lure did not appear to influence whether or not Fish followed it, but they were significantly more likely to attack the smaller lures. Similarly, larger Fish were more likely to attack the lures, while smaller Fish tended to break off following without attacking. Thus, the majority of attacks were by large Fish on small lures.

Multiple lineages of Snakes which have invaded marine habitats have had an increase in neonatal size, combined with a reduced brood size (which are probably connected). Shine et al.'s study suggests that increased predation on smaller Snakes is a plausible explanation for this (although they stress that the results of their study cannot be taken as an absolute proof).

Shine et al. also note that larger Snakes are more likely to survive attacks by Fish, noting that two incidents of Snakes being seized by Fish and then released because the Fish was unable to overpower the Snake have been recorded on reefs close to their study area. In one of these incidents a Chocolate Grouper, Cephalopholis  boenak, unsuccessfully attacked a Turtlehead Sea Snake, Emydocephalus  annulatus, and in the other a Reef Stonefish, Synanceia verrucosa, was forced to break off an attack on a Blue Lipped Sea Krait, Laticauda  laticaudata, suggesting that larger size may present an advantage to young Snakes in surviving attacks, even if Fish do not discriminate against larger Snakes when choosing whether to attack.

A Reef Stonefish, Synanceia verrucosa, making an unsuccessful attack on a Blue Lipped Sea Krait, Laticauda  laticaudata, off the coast of Ile aux Canards in October 2022. Richard Fish/iNaturalist.

Predation is often cited as a likely cause of evolutionary pressure, influencing traits such as size and colouration. However, direct evidence of such impacts is difficult to gather accurate information on this unless predation rates are extremely high. Furthermore, it is difficult to design experiments looking at predatory behaviour for larger Animals without running into ethical and logistical constraints.

Predation is not the only driver of larger size in young marine Snakes which has been made, but it does seem to be the best supported by the available evidence. 

It has been suggested that larger size may provide an advantage when swimming, with smaller Snakes potentially being less efficient swimmers, using more energy to go slower. However, research into Sea Kraits has shown that smaller individuals have a higher swimming speed relative to crawling speed than larger individuals, suggesting that in these marine Snakes smaller size produces an advantage when swimming. 

Another possibility is that larger size in neonatal marine Snakes might be driven by prey size, with a shortage of suitable prey capturable by smaller Snakes creating a need for infant Snakes to be as large as possible. However, many Sea Snakes feed on smaller prey, notably members of the genus Emydocephalus are specialist feeders on Fish eggs, and several members of the genus Hydrophis have miniaturized heads and slender forebodies that enable them to penetrate the burrows of the small Fish upon which they prey.

Another possibility is that intraspecific competition drives larger size in young marine Snakes, with larger individuals excluding smaller individuals from better territories or access to prey. However, aggressive behaviour between members of the same species has never been observed in marine Snakes, making this unlikely.

Finally, larger size can act as a buffer against temperature changes, with larger bodies taking longer to either warm up or cool down that smaller bodies, thereby giving the Snakes more time to react to changes in conditions. However, marine environments offer much more protection against such temperature fluctuations than terrestrial ones, due to the high conductivity of water, making this highly unlikely as a driver of size in marine Snakes.

See also...

Follow Sciency Thoughts on Facebook.

Follow Sciency Thoughts on Twitter.

Trimeresurus ayeyarwadyensis: A new species of Mangrove Pit Viper from the Ayeyarwady and Yangon regions in Myanmar.

The taxonomy of the Asian Pit Viper genus Trimeresurus have proved difficult to unravel, as species tend to be both similar to one-another and morphologically variable. The Mangrove Pit Vipers, Trimeresurus purpureomaculatus and Trimeresurus erythrurus are considered to form a species complex, with Trimeresurus purpureomaculatus being an obligate Mangrove-inhabitant with variable colouration and dark blotches on its back, found in southern Thailand, Peninsula Malaysia, and on the island of Sumatra, while Trimeresurus erythrurus is a green Snake lacking markings, found in but not restricted to Mangroves, found in northern Myanmar, and eastern Bangladesh and India. Between these, in southern Myanmar, is a population of Snakes which show a mixture of traits seen in the other two groups, which have been assumed to represent a zone of hybridization. However, a recent study of genetic structures within the group has suggested that this southern Myanmar population is actually a separate species, which forms a sister taxon to Trimeresurus purpureomaculatus, although this species does show signs of hybridizing with Trimeresurus erythrurus.

In a paper published in the journal ZooKeys on 13 December 2023, Kin Onn Chan of the Lee Kong Chian Natural History Museum at the National University of Singapore, and the School of Biological Sciences at the Universiti Sains Malaysia, Shahrul Anuar, also of the School of Biological Sciences at the Universiti Sains Malaysia, Ananthanarayanan Sankar of the Herpetological Society of Singapore, and the Department of Biological Sciences at the National University of Singapore, Ingg Thong Law and Ing Sind Law, also of the Herpetological Society of Singapore, Rasu Shivaram, also of the Lee Kong Chian Natural History Museum at the National University of Singapore, and of the Herpetological Society of Singapore, Ching Christian, again of the Herpetological Society of Singapore, and of the Department of Life Sciences at the Natural History Museum, Daniel Mulcahy of the Museum für Naturkunde at the Leibniz Institute for Evolution and Biodiversity Science, and Anita Malhotra of the School of Natural Sciences at Bangor University, formally describe the southern Myanmar Trimeresurus population as a new species. 

The new species is named Trimeresurus ayeyarwadyensis, meaning 'from Ayeyarwady'; the species is known from the Ayeyarwady and Yangon regions on the Ayeyarwady delta in southern Myanmar. The species has partially fused first infralabial and nasal scales, a condition not seen in any other member of the genus Trimeresurus, but otherwise shows a mosaic of traits seen in other species.

An unvouchered, live specimen of Trimeresurus ayeyarwadyensis from the Yangon Region, Myanmar. Wolfgang Wüster in Chan et al. (2023).

Unhybridized populations of Trimeresurus ayeyarwadyensis were found in Mangrove forests in the Pyapon and Myaungmya districts of the Ayeyarwady Region, as well as in a forest surrounding a lake unconnected to any Mangrove system in the Hlawga Park in the Yangon Region. In the Pathein District of the Ayeyarwady Region a population of Trimeresurus ayeyarwadyensis hybridized with Trimeresurus erythrurus was found living alongside an unhybridized population of Trimeresurus erythrurus. Trimeresurus purpureomaculatus is known from the Dawei District in the Tanintharyi Region of Myanmar, and could potentially have a contact zone with Trimeresurus ayeyarwadyensis in Mon State, where no members of the genus Trimeresurus have been recorded, but this is thought likely to be due to a lack of searching rather than an absence of Snakes.

See also...

Follow Sciency Thoughts on Facebook.

Follow Sciency Thoughts on Twitter.

Boipeba tayasuensis: An exceptionally large Blindsnake from the Late Cretaceous of Brazil.

Snakes are one of the most successful groups of terrestrial Vertebrates, with over 3800 described extant species. Of these, about 620 are Blindsnakes, Scolecophidia, small, worm-like Snakes with reduced eyes covered by scales, subterminal mouths, and blunt snouts and tails which can make it hard to determine which end is the front. These Snakes are interesting taxonomically, as they retain more Lizard-like features than other Snakes, as well as having a set of derived adaptations for a burrowing environment all their own, which has led to the conclusion that they are the earliest-branching group of extant Snakes, something which has been supported by genetic analysis. However, if this is the case, then Blindsnakes should have appeared in the Late Jurassic or Early Cretaceous, whereas the oldest known fossils assigned to the group come from the Late Palaeocene of Morocco and Early Eocene of Europe.

In a paper published in the journal iScience on 19 November 2023, Thiago Schineider Fachini of the Laboratório de Paleontologia at the Universidade de São Paulo, Silvio Onary, also of the Laboratório de Paleontologia at the Universidade de São Paulo, and of the College of Science and Engineering at Flinders University, and the South Australian Museum, Alessandro Palci and Michael Lee, also of the College of Science and Engineering at Flinders University, and the South Australian Museum, Mario Bronzati of the Laboratório de Evolução e Biologia Integrativa at the Universidade de São Paulo, and  Annie Schmaltz Hsiou, again of the Laboratório de Paleontologia at the Universidade de São Paulo, describe a new species of Blindsnake from the Late Cretaceous  Adamantina Formation of São Paulo State, Brazil.

The new species is named Boipeba tayasuensis, where 'Boipeba' means 'flat Snake' in the Tupi-Guarani language of Brazil, and 'tayasuensis' means 'from Taiaçu' in reference to the location where the specimen was found. The new species is described on the basis of an isolated vertebra articulated with the anterior region of a fragmentary following vertebra, from a fossiliferous outcrop of the Adamantina Formation beside a rural road between the municipalities of Monte Alto and Taiaçu, in the Northwest of the state of São Paulo, Brazil. The Adamantia Formation here has not been precisely dated, but a maximum age of 87.8 million years has been established based upon of uranium-lead dating (uranium-lead dating can give absolute dates for igneous rocks, but only maximum age dates for sedimentary deposits containing derived materials), and the overlying Marília Formation contains Dinosaur bones, indicating that it was laid down before the End Cretaceous Extinction Event.

Holotype of Boipeba tayasuensis. (A) MPMA 16-0008-08, Isolated precloacal vertebra in (upper row) anterior, posterior, and lateral views, respectively, and (lower row) dorsal, and ventral views, respectively. (B) Geographical and geological map showing the type locality where the fossil material was recovered. Abbreviations: cn., condyle; ct., cotyle; ns., neural spine; ptz., postzygapophysis; ppz., prezygapophyseal accessory processes; pz., prezygapophysis.; sf., subcentral foramina; sy., synapophysis; zs., zygosphene. Fachini et al. (2023).

The specimen shows a number of features that are known only in members of the crown group Scolecophidia (the crown group comprises everything descended from the last common ancestor of all living members of a group). These include  (1) dorsoventrally flattened vertebra, (2) absence of median notch in the posterior border of the neural arch, (3) narrow and cylindrical centrum, (4) absence of hemal keel and/or median ventral prominence between the cotyle and condyle, (5) presence of asymmetrical subcentral foramina, (6) weakly developed precondylar constriction, (7) cotyle and condyle oval in anteroposterior view, (8) the presence of well-developed prezygapophyseal processes, and (9) undivided synapophyses with no distinction between the para- and diapophyseal articular facets. Furthermore, the specimen has synapophyses located dorsal to the ventral margin of the cotyle, a feature seen only in members of the Family Typhlopidae.

Three-Dimensional Reconstruction of Boipeba tayasuensis. (A)–(E) MPMA 16-0008-08, isolated precloacal vertebra in (A) anterior, (B) posterior, (C) lateral, (D) dorsal, and (E) ventral views. Abbreviations: Cn, condyle; ct., cotyle; nc, neural canal; ns., neural spine; ptz., postzygapophysis; ppz., prezygapophyseal accessory processes; pz., prezygapophysis.; sf., subcentral foramina; syn., synapophysis; zg, zygantrum; zs., zygosphene. Fachini et al. (2023).

Although the material assigned to Boipeba tayasuensis is extremely limited, it is entirely consistent with derivation from a Snake, and in particular a Blindsnake, showing no real similarity to any member of any other group. A phylogenetic analysis recovered the specimen as being firmly placed within the Scolecophidia, forming a sister group to the living Typhlopidae.

Boipeba and the Evolution of Snakes. (A) Phylogenetic relationships of the giant fossil Blindsnake Boipeba and other major snake lineages, based on Bayesian and parsimony analyses of morphology and DNA;  numbers at Blindsnake clade are Bayesian posterior and parsimony bootstrap support. Divergence dates for living Snakes are based on molecular dates; ; bold lines indicate stratigraphic range or uncertainty for fossil taxa. Quotes denote non-monophyletic taxon names. (B) Size distribution of all species for each major living Snakes lineage and important fossil taxa, on a log scale; note Boipeba is larger than living Blindsnakes. (C) Boipeba greatly increases the size estimate for the most recent common ancestor of living Blindsnakes. Fachini et al. (2023).

The vertebra of Boipeba tayasuensis has a centrum length of 6.8 mm, exceptionally large compared to that of most modern Blindsnakes, leading to an estimated total length of 110 cm. This is three and a half times the size of most living Typhlopoids, which are themselves among the largest Blindsnakes, although it would be a fairly average size for most modern Snake groups, as well as most known Mesozoic Snakes, suggesting that small size is a derived feature in modern Scolecophidians.

Life reconstruction of Boipeba tayasuensis. This large Cretaceous Blindsnake inhabited the arid palaeoenviroment of the Bauru Basin, Brazil, alongside Titanosaur Sauropods, Theropods, and terrestrial Crocodiles such as Montealtosuchus (Mesoeucrocodylia, Peirosauridae). The latter was found in the same outcrop as Boipeba. Jorge Blanco in Fachini et al. (2023).

Until the oldest known Blindsnakes come from the Palaeocene of Morocco and the Eocene of Europe, making Biopeba the oldest known, and the fisrt Mesozoic member of the group, as well as between 10 and 28 million years older than the next oldest known member of the group. A phylogenetic study recovered Biopeba as the sister taxon to the Family Typhlopoidea, which is consistent with molecular clock predictions that that group originated in the Cretaceous.

This in turn has biogeographical implications for the origin of the Typhlopoidea, suggesting that the group may have emerged in Western Gondwana (i.e. modern South America), instead of Eastern Gondwana (India or Madagascar) as previously theorised. The find also supports the younger of two possible origin dates for the Typhlopoidea, at about 122 million years ago in the Early Cretaceous, rather than about 150 million years ago, in the Late Jurassic.

Because Biopeba is recovered as more closely related to the Family Typhlopoidea than the Family Leptotyphlopidae, it also provides a minimum age for the divergence of these two groups.

Biopeba is a giant among Blindsnakes, but of fairly average size for most Snake groups, with the exception of the living Boas and Pythons, and some extinct stem group Snakes (i.e. Animals more closely related to living Snakes than to any other living group, but not decended from the last common ancestor of all living Snakes). This suggests that the small size of modern Blindsnakes is a derived character, and that the ancestors of the group were much larger Animals than had previously been theorized. In addition, small size appears likely to have apeared separately in the three major Blindsnake lineages. 

Large size is extremely rare in modern Blindsnakes, but may have been normal in Cretaceous members of the group. The small size of modern Blindsnakes may be a result of the End Cretaceous extinction, which smaller cryptic Animals had a better chance of surviving. It has been suggested that the earliest Snakes were small burrowing Animals, at least in part because the burrowing Blindsnakes are thought to be the earliest branching Snake group. However, the large size of Biopeba suggests that this extrapolation is false, and that the earliest Blindsnakes were more similar in size to other Snake groups, rather than the other way round.

See also...

Online courses in Palaeontology. 

Follow Sciency Thoughts on Facebook.

Follow Sciency Thoughts on Twitter.

Naja fuxi: A new species of Cobra from China.

Cobras, Naja spp., are a highly distinctive and widespread group of Venomous Snakes, responsible for many cases of Snake-bites in Humans across a wide geographical area every year, with the number of bites being particularly high in South and Southeast Asia and southern China. The toxins found within the venom of Cobras varies from species to species, with the effect that an antivenom developed to treat the bite of one species will not counteract the venom from the bite of another. Unfortunately, the taxonomy of Asian Cobras is still not fully understood, with many populations potentially assigned to the wrong species, or even to cryptic species (species which resemble other species upon physical examination, but which are genetically distinct).

All Asian Cobras were originally placed in the species Naja naja by Linnaeus in 1758, with multiple subspecies and colour variants recognised in the following years. Eventually, this proved to be unreliable, with the species being split into several new species from 1768 onwards. There are now twelve recognised species of Cobra in Asia, including two found in China.

The Monocled Cobra, Naja kaouthia, was first described by René-Primevère Lesson from Bengal (modern Bangladesh) in 1831. Populations of Cobras assigned to this species are currently found in northeastern India, Bangladesh, Bhutan, Nepal, Myanmar, Cambodia, Laos, northern Malaysia, southern Vietnam, Thailand and southern China. However, these species vary greatly in their colouration, spitting behaviour, and even the composition of their venom, making it likely that not all these Cobras do in fact belong to the same species. In China this species is known from the south and southwestern parts of Yunnan, the southwestern part of Sichuan, Xizang (Tibet Autonomous Region), and Guangxi. 

The Chinese Cobra, Naja atra, is known from southern China, south of the Yangtze River, including Zhejiang, Fujian, Taiwan, Guangdong, Hainan, Guangxi, Macao, Hong Kong, Jiangxi, Anhui, Hubei, Hunan and Guizhou. It is also found in northern Vietnam. The Yunnan population of this species is known to be genetically distinct from other populations, including that from Zhoushan Island in Zhejiang Province, which is the population from which the species was first described. 

Thus, both populations of Cobras in Yunnan Province, appear to present taxonomic problems, and may not belong to the species to which they are currently assigned.

In a paper published in the journal Animals on 9 December 2022, Sheng‑Chao Shi of Guangxi Normal University, and the Chengdu Institute of Biology, Gernot Vogel of the Society for Southeast Asian Herpetology, Li Ding, also of the Chengdu Institute of Biology, Ding‑Qi Rao and Shuo Liu of the Kunming Institute of Zoology, Liang Zhang of the Institute of Zoology of the Guangdong Academy of Sciences, Zheng‑Jun Wu, also of Guangxi Normal University, and Ze‑Ning Chen, again of Guangxi Normal University, and the Chengdu Institute of Biology, re-examine the distributions of Naja kaouthia and Naja atra in China and South and Southeast Asia, and describe a new species of Cobra from China.

The new species is named Naja fuxi, in reference to Fuxi (伏羲), an ancestral spirit in Chinese mythology, often depicted as a half-Man, half-Snake figure in a rearing Cobra posture. It is described from 34 specimens from Sichuan and Yunnan provinces, from populations previously assigned to Naja kaouthia.

Naja fuxi in life and habitats. (A), (B) Dorsolateral view and hood pattern of adult female paratype CIB DL2018081005 from Panzhihua, Sichuan, China; (C), (D) Dorsolateral and front view of an unvouchered adult from Jiangcheng, Pu’er, Yunnan, China; (E), (F), two adults from Wenshan, Yunnan, China; (G) Subtropical Forest at type locality Panzhihua, Sichuan, China; (H) Tropical monsoon forest and farmland at Jiangcheng, Pu’er, Yunnan, China. Sheng-Chao Shi, Li Ding & Liang Zhang in Shi et al. (2022).

The examined adult specimens of Naja fuxi ranged from 680 to 1165 mm in length, and can be distinguished from other Cobras by the presence of a series of well-spaced narrow crossbands along the length of the body and tail. These Snakes are mostly buff-coloured, and have 19-29 scale rows on the front part of their bodies, 19-27 on their mid-section, and 12-19 on the posterior part. The fangs are short, and not adapted to spitting.

Naja fuxi was found in tropical and subtropical areas at altitudes of between 1000 and 1400 m above sealevel. It favours gentle slopes, with open bush or forest edge environments. It is known to consume a wide range of prey, including Frogs, Snakes, Birds, and small Mammals. It sometimes enters settlements to take chicks, creating a potential for conflict with Humans, and records suggest it is the Snake responsible for most bites suffered by Humans in Xishuangbanna Prefecture.

See also...

Follow Sciency Thoughts on Facebook.

Follow Sciency Thoughts on Twitter.

Geckos from the Early Eocene Dormaal Site in Belgium.

The Middle and Late Eocene Lizard faunas of Europe are relatively well known, thanks to a number of lagerstätten (deposits with exceptional preservation) such as the Messel Shale of Germany. However, the Lizards of the Early Eocene are much less well understood, due to a paucity of such sites. This is unfortunate, as this interval starts with the Palaeocene-Eocene Thermal Maximum at 56 million  years ago, the which saw the warmest temperatures of the past 66 million years, with Northern Europe developing a sub-tropical to tropical climate, and therefore presumably being a particularly good environment for Lizards.

One exception to this lack of Early Eocene is the Dormaal locality at  Zoutleeuw, eastern Belgium, where a fluvial deposit comprised of layers of clayey and lignitic (coal-rich) sands are interbedded with lenses of grey clays. These deposits are thought to have been laid down in a system of rivers and lagoons in the earliest Eocene, and have yielded a diverse fauna of Mammals, Lizards, Fish, Turtles, and Crocodiles.

In a paper published in the journal Royal Society Open Science on 29 June 2022, Andrej Čerňanský of the Department of Ecology at Comenius University in Bratislava, Juan Daza of the Department of Biological Sciences at Sam Houston State University, Richard Smith of the Directorate Earth and History of Life at the Royal Belgian Institute of Natural Sciences, Aaron Bauer of the Department of Biology and Center for Biodiversity and Ecosystem Stewardship at Villanova University, Thierry Smith, also of the Directorate Earth and History of Life at the Royal Belgian Institute of Natural Sciences, and Annelise Folie of the Scientific Survey of Heritage at the Royal Belgian Institute of Natural Sciences, describe A new species of Gacko from the Dormaal Site.

Location of the earliest Eocene locality of Dormaal (MP7, Belgium) that has yielded Dollogekko dormaalensis and the early Eocene locality of Prémontré (MP10, France) that has yielded Laonogekko lefevrei. Čerňanský et al. (2022).

Geckos as a group have a poor fossil record, due to their lightly mineralised and easily disarticulated skeletons. The oldest known Geckos come from the Early Cretaceous amber deposits of Myanmar, with Geckos also known from Eocene Baltic Amber and Miocene Dominican Amber. Outside of these amber deposits, however, almost all fossil Geckos are known from isolated skeletal elements. Geckos have previously been recorded from the Dormaal locality, but never actually formally described.

The new species is named Dollogekko dormaalensis, where 'Dollogekko' honours the prominent Belgian palaeontologist Louis Dollo (1857-1931), combined with '-gekko' the Malay root word of the English 'gecko', often used as a suffix for generic names within the group, and 'dormaalensis' means 'from Dormaal'. The species is described from a single incomplete frontal bone (the bone that forms the forehead in Humans).

Dollogekko dormaalensis, the holotypic frontal IRSNB R 452 in (a) dorsal, (b) ventral, (c) right lateral,(d) left lateral and (e) anterior views. Čerňanský et al. (2022).

The frontal bones of Geckos tend to be highly distinctive at the species level, making it possible to reliably describe new taxa on these bones alone. The specimen from which Dollogekko dormaalensis is described comprises about the anterior half of the frontal bone, with the posterior half being lost. The preserved portion is 4.3 mm in length, is tubular-to-funnel-shaped (the whole bone would almost certainly have been hourglass shaped), and would have extended about ¾ of the way around the orbit. 

Dorsal view of the skull of some extant Geckos exhibiting diversity of frontal bone shape and sculpturing (yellow). (a) Carphodactylidae, Underwoodisaurus  milii (CAS  74744),  (b)  Diplodactylidae, Rhacodactylus  leachianus (MCZ–R15967), (c) Phyllodactylidae, Thecadactylus rapicauda (CAS 95146) and (d) Gekkonidae, Chondrodactylus angulifer (CAS 126466). Čerňanský et al. (2022).

In addition to the partial frontal from which Dollogekko dormaalensis is described, Čerňanský et al. also describe two fragments of dentary and a partial mandible from the same deposit. The dentary fragments appear to be from a Gecko about the same size as Dollogekko dormaalensis, while the partial mandible appears to come from an Animal about twice the size. Since the frontal bone from which Dollogekko dormaalensis is described is fully fused, and therefore presumed to come from an adult individual which has stopped growing, this appears likely to represent a separate species. The dentary fragments are of a size compatible with he frontal bone, but it is impossible to confirm that they belong to the same species, derive from a juvenile of the species which produced the mandible, or represent a third species. Due to this uncertainty, and the low value of mandible fragments for taxonomic purposes, none of these specimens are named, but instead referred to as Gekkota indet 1 (dentaries) and Gekkota indet 2 (mandible).

Gekkota indet. 1, the dentaries IRSNB R 454 and IRSNB R 453; Gekkota indet. 2, the mandible fragment IRSNB R 456 in(a), (e), (i) lateral, (b), (f), (j) medial, (c), (g), (k) dorsal, (d) ventral and (h) anterior views. Čerňanský et al. (2022).

See also...

Online courses in Palaeontology. 

Follow Sciency Thoughts on Facebook.

Follow Sciency Thoughts on Twitter.