High diversity of Raoellidae (Artiodactyla, Mammalia) from the middle Eocene Subathu Group of Kalakot, Northwest Himalaya, India

The middle Eocene Subathu Group of Kalakot area (northwest Himalaya, India) is well known for its diverse mammalian fauna, especially of raoellid artiodactyls, which are presently represented by four genera: Indohyus, Khirtharia, Kunmunella, and Metkatius. Our recent work on artiodactyls from the Kalakot area recovered several new taxa in addition to earlier known raoellids. The first new taxon is characterized by its small size, higher and more conical lower molar cusps than in Khirtharia and Metkatius; protoconid and metaconid closely appressed; crista obliqua meets at trigonid notch, presence of an hypolophid and a welldeveloped labial cingulid; bunodont upper molars, subrectangular M1-M2, and subtriangular M3, large metaconule (pseudohypocone) and small well distinct paraconule; cristae well distinct, small metastyle on M3 (absent in the four other raoellid genera), slightly inflated anterior and posterior cingulae. The second new taxon is the smallest of all known Raoellidae; it has bunodont lower molars with tiny paraconid in m1-2 (paraconid is absent in all other raoellids) and crista obliqua meeting the labial base of protoconid; m3 with an hypolophid and well-individualized hypoconulid centrally placed and higher than entoconid; M2 subrectangular, protocone higher than metacone, para and metastyle less distinct than in Indohyus and Kunmunella, ectoloph distinct. Besides these two new taxa, Khirtharia dayi known from Pakistan is reported for the first time from India on the basis of its morphology and size of m3. A new species of Metkatius is characterized on the basis of m1-2, which differ from those of M. kashmirensis by the metaconid higher than the protoconid and by being more than 20% larger. Outside the Indian sub-continent, raoellid artiodactyls are also known from the middle Eocene Pondaung Formation of Myanmar and Shanghuang fissure filling of Jiangsu, China. The predominance of the family Raoellidae in Kalakot provides new information about their phylogenetic position and allow to discuss their origin, evolution, and dispersals. This work is partly funded by project BR/121/A3/PALEURAFRICA from the Belgian Science Policy Office.

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Paleontology