The Role of Postcranial Skeleton Morphology in Species Identification and Phylogeny Inferences: Gerbillinae (Rodentia: Muridae) as a Case Study

Abstract

Identification of rodents usually has been done based on cranial and dental characters. Postcranial skeleton has been ignored in spite of its importance in archaeozoology for identification of skeletal remains. Herein, we intended to determine the importance of postcranial skeleton in identification and classification of gerbilline rodents in Iran. Different skeletal parts of 82 specimens belonged to five genera and ten species were extracted using papain digestion. A total of 62 characters with 142 character states were defined as informative postcranium variations for separating taxa. Results showed that reconnaissance of specimens belonging to the genera Tatera, Gerbillus, and Rhombomys was possible using morphological characters of vertebral column and thorax, pectoral girdle and forelimb, and pelvic girdle and hindlimb. Moreover, these morphological characters could be useful for identification of Meriones species. For cladistic analyses, the data matrix scored for two characters of external anatomy, 20 of vertebral column, 11 of pectoral girdle, seven of pelvic girdle, ten of forelimb and 12 of hindlimb was provided. The cladogram resulted from strict consensus method, employed in PHYLIP, was comparable with phylogenetic trees inferred from cranial morphology and molecular studies. Finally, an identification key for Gerbillinae was provided based on postcranium characteristics.