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.
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).
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