Serpentirhabdias orientalis sp. nov. (nematoda: rhabdiasidae), a new lungworm species in naja kaouthia from Thailand: the first record of the genus from the oriental region and an elapid snake

A new lungworm species, Serpentirhabdias orientalis sp. nov., was discovered in the respiratory organs of the monocled cobra (Naja kaouthia) in Thailand, marking the first record of a Serpentirhabdias species in both the Oriental Region – Southeast Asia – and in an elapid snake. Morphological analysis revealed distinctive features that clearly differentiate it from all 22 previously known species, such as an elongated body (up to 5858 μm), 6 onchia, a triangular oral opening, and a thin cuticle. The species also exhibited significant differences in several characteristics, such as tail length, distance from the anterior end to the excretory pore and the number of eggs in the uteri, when compared to closely related species such as Serpentirhabdias moi and Serpentirhabdias mussuranae. Specimens were analysed using light microscopy, and genetic sequencing of COI and 28S rRNA confirmed its distinctiveness. Phylogenetic analysis, reinforced by morphological data, revealed a close relationship between S. orientalis sp. nov. and Neotropical species, raising intriguing questions about the biogeography and evolutionary history of lungworms. The high prevalence and intensity of infection in the monocled cobras could have ecological consequences, potentially impacting the health of wild snake populations. Increasing wildlife–human interactions highlight the need to monitor parasitic infections for ecological and veterinary insights. These findings contribute to the expanding taxonomy of Serpentirhabdias and emphasize the importance of further research into parasitic infections in both wild and captive reptiles, with potential implications for conservation and veterinary management.