The discovery, published in the journal Evolutionary Systematics, resolves a puzzle that has lingered since 2010, when researchers first recorded a single specimen of a wolf snake on Great Nicobar Island and identified it as Lycodon subcinctus, the banded wolf snake, a species then thought to range widely across Southeast Asia and Indonesia. That lone specimen, deposited at the Zoological Survey of India in Port Blair, was all anyone had to go on. Recent taxonomic revisions of the Lycodon subcinctus group raised doubts about whether the Nicobar population truly belonged to the mainland species, but with no additional specimens and no genetic data, its identity remained unresolved.

Wolf snakes of the genus Lycodon are small to medium-sized nocturnal hunters that form an integral part of the Oriental snake fauna. Over the past two decades, the genus has undergone substantial taxonomic upheaval, with revisions of several widespread species and the description and revalidation of numerous old names. This has made Lycodon the second-most speciose snake genus in Asia, with 74 recognised species. The group at the centre of the new study, the Lycodon subcinctus group, was historically treated as a single, morphologically variable species distributed across much of mainland Southeast Asia and the Indonesian islands, but recent work has split it apart piece by piece.

That splitting process has been remarkably productive. Populations from Palawan and Borneo were elevated to full species status as Lycodon sealei. A population from southern China, once attributed to the name Lycodon maculatus, was found to bear a name that actually belonged to a Mexican species, prompting researchers to coin a new name, Lycodon neomaculatus, for the Chinese mainland population. Most recently, a neotype was designated for Lycodon subcinctus itself from Penang in peninsular Malaysia, anchoring the true identity of the species. With the taxonomy of the group largely settled, one glaring exception remained: the insular population from the Nicobar Islands, India.

To settle the question, the research team re-examined the original 2010 specimen, traced a second uncatalogued specimen from the same population held at the Zoological Survey of India, and collected a fresh adult female from Great Nicobar Island. The three specimens, all adult females, were subjected to detailed morphological examination, with measurements taken using digital calipers and scale counts following standard protocols. The fresh specimen, collected near Gandhi Nagar at an elevation of 140 metres, was designated the holotype and housed at Pondicherry University’s Department of Ocean Studies and Marine Biology in Port Blair.

The molecular analysis proved decisive. Genomic DNA was extracted from preserved tissue of the holotype, and fragments of the mitochondrial cytochrome b gene and the nuclear c-mos gene were amplified and sequenced. Maximum likelihood phylogenetic analysis, run with 100,000 bootstrap replicates, placed the Nicobar snake firmly within the Lycodon subcinctus group, as the sister lineage to Lycodon subcinctus itself with strong statistical support. Crucially, the uncorrected pairwise sequence divergence at cytochrome b was 6 percent from Lycodon subcinctus and between 6 and 17 percent from other members of the group, thresholds well within the range used to delineate species in this genus and related colubrid snakes.

The morphology tells the same story. Lycodon irwini is a fairly large, slender wolf snake, with the largest known specimen measuring nearly 1.2 metres in total length. Its dorsum is a uniform glossy black, lacking the white bands seen in some relatives, and its ventral surface is greyish black with a cream-coloured ventrolateral ridge. It can be distinguished from all other members of the group by a combination of traits: a preocular scale that is occasionally present, a prefrontal scale that never touches the eye, a higher count of ventral scales ranging from 223 to 238, and more subcaudal scales than any of its closest relatives. These are not trivial differences but the kind of anatomical characters routinely used to separate species in this group.

What makes the discovery especially striking is the snake’s apparent rarity. Only four records of Lycodon irwini are known, three of them based on the specimens described in the study, and all from Great Nicobar Island. Despite targeted surveys on other islands in the archipelago, the species has not been recorded anywhere else, suggesting it is likely endemic to Great Nicobar. The holotype was found on a road in moist evergreen forest, and another specimen was observed crossing a road in similar habitat. The researchers believe the snake may be naturally scarce, highly cryptic, and possibly confined to the island’s evergreen forests, which makes every encounter precious.

This rarity, combined with the restriction to a single island and the potential threats from ongoing development activities that could impact its only known habitat, has led the authors to recommend that Lycodon irwini be classified as Endangered on the IUCN Red List. Great Nicobar Island, part of the Sundaland biodiversity hotspot, covers a small area but hosts a remarkable variety of habitats, including mangrove marshlands, grasslands, and dense evergreen forests. The herpetofauna of the Nicobar Islands is exceptionally diverse, with many endemic species, yet the archipelago has a long history of misidentified records and incomplete surveys, meaning new species continue to emerge from collections and fieldwork alike.

The confirmation of Lycodon irwini adds to a growing body of evidence that the diversity and endemism of vertebrate species in tropical regions, particularly on islands, are significantly underestimated. Although herpetological research in the Nicobar Islands has been ongoing since the mid-1800s, the archipelago continues to reveal unique, previously unknown lineages. The islands, biogeographically linked to Sundaland yet isolated across the Ten Degree Channel, may harbour distinct lineages shaped by their isolation, underscoring the need for focused taxonomic work and conservation efforts. For now, a snake named after one of the world’s most beloved wildlife educators has taken its place in the catalogue of life, a reminder that even in the twenty-first century, remote islands can still guard secrets worth discovering.

Subject of Research: Biodiversity

Article Title: A ‘Crikey’ new snake: An insular Lycodon Fitzinger, 1826 ( Squamata , Colubridae ) from the Nicobar Archipelago, India

Article References: Naveen, R. S., Mirza, Z. A., Choure, G., & Chandramouli, S. R. (2025). A ‘Crikey’ new snake: An insular Lycodon Fitzinger, 1826 (Squamata, Colubridae) from the Nicobar Archipelago, India. Evolutionary Systematics, 9(2), 221-228. https://doi.org/10.3897/evolsyst.9.170645

Image Credits: AI Generated

DOI: 10.3897/evolsyst.9.170645

Keywords: Lycodon irwini, Great Nicobar Island, new species, wolf snake, taxonomy, herpetology, biodiversity, IUCN Red List, Nicobar Islands, Steve Irwin, Crikey, snake

Perinereis obfuscata belongs to Nereididae, one of the most species-rich families within the segmented marine worms known as polychaetes. Worldwide, the family encompasses 46 valid genera and 771 species, and its members are among the most conspicuous animals of intertidal ecosystems. Ragworms are voracious predators and scavengers with an eversible proboscis armed with paired jaws, and they form a vital link in coastal food webs as prey for fish and shorebirds. In Indian waters, 71 nereidid species have been documented so far. Within the family, the genus Perinereis stands out as the second most diverse after Nereis, with 119 valid species globally, 20 of which had been recorded from Indian coastal zones before this study.

What sets Perinereis apart from its relatives is the architecture of the proboscis. The genus is defined by distinctly separated conical paragnaths, tiny tooth-like structures arranged on both the maxillary and oral rings of the eversible pharynx, together with characteristic bar-shaped paragnaths on a region called area VI. These microscopic armaments function like a fingerprint: their number, shape, and distribution on each area of the proboscis are among the most reliable characters for telling closely related species apart. In an earlier landmark revision, Hutchings, Reid, and Wilson subdivided Perinereis into three major groups, G1 through G3, based on proboscidal and parapodial morphology. Group 1 species carry a single transverse bar on area VI, and the group is further split into subgroups A and B according to how much the dorsal ligule, a fleshy lobe of the parapodium, is expanded in the posterior segments.

Perinereis obfuscata falls squarely into this G1 group. Originally described from the Philippines by Adolph Grube in 1878, the species has since been reported from scattered localities across the Indo-Pacific, including Australia and the Arabian Gulf. Its key diagnostic traits include a single bar-shaped paragnath on area VI and a barely expanded proximal region of the dorsal ligule in the posterior parapodia, a combination that recently led researchers to move it from subgroup 1B into subgroup 1A. Until now, however, the only Indian record of the species came from the Great Nicobar Island, published in 2008 by Rajasekaran and Fernando. That record carried a serious handicap for modern taxonomy: it provided no repository details and no voucher number, meaning the identification could never be independently verified against preserved material.

The newly confirmed specimen, catalogued as ZSIHQ/GNC/An8519/2, changes that picture. Collected by B.P. Halder and preserved according to standard protocol, relaxed in seawater, fixed in 10 percent formalin, and stored in 70 percent ethanol, it measures 39.14 millimeters in length and 2.65 millimeters in width at the tenth chaetiger, with 64 segments. Under Leica stereo-zoom and compound microscopes, Bose documented the full suite of diagnostic characters. The prostomium is roughly trapezoidal with tapering conical antennae and four pairs of tentacular cirri, the longest reaching back to the fourth chaetiger. The dark brown jaws carry approximately seven teeth each. Most importantly, the everted proboscis displays the species’ signature paragnath formula: eight cones in a triangular arrangement on area I, 16 to 17 cones in crescent rows on area II, 28 cones on area III, 35 to 36 on area IV, a single cone on area V, one short crescent-shaped bar on area VI, and 38 to 40 cones in two rows across areas VII and VIII.

The parapodial anatomy matched expectations for subgroup 1A as well. In anterior segments, the triangular dorsal ligule is 1.14 times longer than the median ligule, while in posterior parapodia the proximal region of the dorsal ligule is slightly enlarged, the trait that anchors the species’ current subgroup assignment. The chaetae, the bristles that polychaetes use for crawling and swimming, followed the expected pattern: coarsely serrated homogomph spinigers in the notopodia, and a mix of homogomph spinigers, heterogomph spinigers, and short, finely serrated heterogomph falcigers in the neuropodia. Interestingly, the examination also revealed a previously undocumented feature: the ridges of areas VI-V-VI form a pi-shaped pattern in which the ridges of area VI are distinctly separated submedially by concave furrows, corresponding to a subdivision within the pi-pattern scheme described by taxonomist Turna Villalobos-Guerrero in 2019.

Not every character matched the literature perfectly, and those discrepancies are scientifically valuable. Compared with the Australian material studied by Hutchings and colleagues in 1991, the Gujarat specimen has distinctly longer tentacular cirri and higher counts of conical paragnaths on areas IV and VII-VIII, and it lacks the black transverse line on each side of the posterior margin of anterior segments reported in recent identification keys. Such variations may reflect intraspecific variability across the species’ enormous geographic range, or they may hint at cryptic diversity lurking within the current species concept. Either way, they underscore why voucher specimens and detailed morphological documentation matter: without preserved material, none of these comparisons would be possible.

The biogeographic implications are striking. A jump from the Great Nicobar Island to the Gujarat coast represents a significant range extension across the breadth of the Indian Ocean rim of the subcontinent. Like many marine invertebrates, nereidids produce planktonic larvae capable of long-distance dispersal via ocean currents, which could plausibly explain the disjunct distribution. However, larval dispersal capacity varies among species and depends heavily on ecological conditions, so the hypothesis remains untested until population-genetic studies can compare mainland and island specimens. It is also possible that P. obfuscata was never truly absent from the west coast, simply overlooked: the rocky, silty intertidal habitats of Gujarat closely resemble the shores of Maharashtra and Goa, where several new Perinereis species have recently been discovered, and limited sampling has long constrained knowledge of India’s polychaete fauna.

Beyond the species itself, the study nudges India’s tally upward: with P. obfuscata and the previously undercounted P. suluana taken into account, the number of Perinereis G1 species known from India rises to ten, and the national total of Perinereis species climbs from 20 to 21. Eight Perinereis species are now documented from Gujarat alone, though only one, P. khambhatiensis, was originally described there. Because the Gujarat specimen was collected in 1990, the current status of the population remains unknown, and targeted field surveys are needed to determine whether the species still persists at the type locality and where else it may hide. For now, the finding stands as a vivid reminder that museum collections are not archives of the past but living datasets, and that some of the most important discoveries in marine biodiversity may already be sitting, patiently preserved, in a storeroom drawer.

Subject of Research: First voucher-confirmed record of the polychaete ragworm Perinereis obfuscata from the mainland coast of India, based on re-examination of a museum specimen from Gujarat.

Article Title: First confirmed record of Perinereis obfuscata (Grube, 1878) (Polychaeta: Nereididae) from the coastline of Indian mainland

Article References: Bose, M. (2026). First confirmed record of Perinereis obfuscata (Grube, 1878) (Polychaeta: Nereididae) from the coastline of Indian mainland. Discover Oceans, 3(1), Article 56. https://doi.org/10.1007/s44289-026-00170-0

Image Credits: AI Generated

DOI: 10.1007/s44289-026-00170-0

Keywords: Polychaeta, Nereididae, Perinereis, Perinereis obfuscata, ragworm, Gujarat coast, Great Nicobar Island, museum voucher specimen, range extension, marine biodiversity, paragnath morphology, Zoological Survey of India