Dental and Cranial Morphological Studies Based on New Collection of Neogene Suids from the Siwalik Hills of Pakistan

Abstract

A detailed taxonomic investigation of the abundant and diverse group of suid fossil materials from different formations of the Siwaliks of Pakistan has been worked out. Comparative morphological and morphometric features of suids have been studied in this dissertation. Mostly already described localities produce fossil remains. More than 14 localities have been explored for fossil collection. More than 114 specimens, collected from different localities of the Lower, Middle and Upper Siwaliks have been described. These fossils document 12 suid species belonging to 9 genera and 4 subfamilies. Among these, eight specimens belong to the genus Hyotherium, twenty two specimens belong to the genus Listriodon, twenty five specimens belong to the genus Conohyus, three specimens belong to the genus Tetraconodon, 4 belong to the genus Sivachoerus, twenty one specimens belong to the genus Propotamochoerus, seventeen specimens belong to the genus Hippopotamodon, thirteen specimens belong to the genus Hippohyus, and one specimen belongs to the genus Sivahyus. Listriodon pentapotamiae, Conohyus sindiensis, Hyotherium pilgrimi and Conohyus indicus have been described from Middle Miocene of Lower Siwaliks. Late Miocene to Early Pliocene of Middle Siwaliks yielded Tetraconodon magnus and Conohyus indicus. H. lydekkeri, H. sivalensis and S. punjabiensis have been found from Pliocene to Pleistocene of Upper Siwaliks. Propotamochoerus hysudricus and Hippopotamodon sivalense have been disovered both from Middle and Upper Siwaliks. Quantitatively, remains of genus Listriodon were most abundant in the Siwaliks. However, Hippopotamodon, Conohyus and Propotamochoerus ii were also diverse in the Siwaliks. The species Hippohyus lydekkeri, Hippohyus sivalensis, Conohyus indicus and Hyotherium pilgrimi were uniformely present in the Siwaliks. There is poor fossil record of Tetraconodon minor and Sivahyus punjabiensis in the Siwaliks. The described specimens include some complete maxillary and mandibular tooth series (P1-M3), isolated teeth, fragments of maxillae, mandibles and skulls. Fossil remain of Tetraconodon minor is first time described from middle Siwaliks of Pakistan. The skulls bearing almost complete right and left tooth series of Hippopotamodon and Propotamochoerus are new addition to suid fauna of the Middle Siwaliks of Pakistan. A map showing the stratigraphic ranges of various taxa of Siwalik suids has also been designed in this dissertation.