Tropidonotus nicobarensis Sclater, 1891 is an enigmatic snake currently referred to the natricine genus Hebius Thompson, 1913. No specimens have been recorded since the original discovery of the name-bearing type in the late 19th century, which was allegedly collected on Kamorta Island in India’s Nicobar Archipelago. Recently, a second observation of this species was reported from Havelock Island (Swarajdweep) in the nearby Andaman Archipelago. However, the snake in question is clearly conspecific with another natricine, Thamnophis saurita (Linnaeus, 1766), native to eastern North America. This discovery prompted us to examine the type specimen of Tropidonotus nicobarensis, which revealed that it too is conspecific with Thamnophis saurita. The provenance of the Tropidonotus nicobarensis type specimen and the Havelock Island snake are discussed, with the latter likely representing an introduced animal.

Species of the agamid genus Bronchocela Kaup, 1827 in the Andaman and Nicobar Islands are reassessed based on newly collected specimens from different parts of the Nicobar Archipelago. An assessment based on morphology and distribution of the identified groups reveal two new, unnamed populations, one allied to B. cristatella and the other allied to B. danieli. These two populations are described as new species, and Bronchocela cristatella is redescribed based on Sundaic specimens. The remaining species, B. danieli and B. rubrigularis are redescribed. Distributions of all of these four species are mapped and recommendations on their conservation status are suggested.

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