Rhinoceronema unicornensis gen. n., sp. n. (Cosmocercoidea: Atractidae) from Indian one horned Rhinoceros (Rhinoceros unicornis Linnaeus, 1758) captivated at the Alipore Zoological Garden, Kolkata, India.

During survey of nematodes from the faecal samples of Rhinoceros unicornis Linnaeus, 1758 remaining captivated in the Alipore Zoological Garden, Kolkata, India 2,500 specimens were recovered in 3 years from March, 2007 to February, 2010. After processing the specimens were identified as a member of the family Atractidae (Railliet 1917) Travassos 1919 which have 22 valid genera. The present specimens differs from all other valid atractid genera in the features of cephalic region, cup-shaped buccal cavity with a pair of teeth, structure of the oesophagus and coarse transversely striated body. A new genus Rhinoceronema has been created to accommodate the present newly erected type species R. unicornensis. A Key to the genera of family Atractidae is added.