Morphological and molecular phylogenetic characteristics of dwarf Sus specimens from the Noguni shell middens in the Ryukyu Islands

Abstract

We analyzed the morphological and molecular phylogenetic characteristics of Sus bone and tooth specimens excavated from the Noguni shell midden and the Noguni B shell midden (c. 7200–4400 uncal. BP), in Okinawa main island. They were compared with those of Sus remains from later sites on the Okinawa Islands (c. 4800–1400 uncal. BP) as well as modern Ryukyu wild boar (Sus scrofa riukiuanus). Based on the length and breadth of lower third molars, Sus specimens from the Noguni shell middens were distinctly smaller than those from modern Ryukyu wild boar. Lower third molars from the Noguni shell middens also show a different size range from those of other ancient sites in the Okinawa Islands. Some haplotypes from the Noguni B shell midden belong to a different cluster from modern Ryukyu wild boar based on the analysis of mitochondrial DNA D-loop region, although nucleotide sequences are fragmentary. The morphological and molecular phylogenetic analyses indicate that Sus from the Noguni shell middens included different populations from modern Ryukyu wild boar. We suggest two possible hypotheses: first, the Sus from the Noguni shell middens were introduced to Okinawa main island from elsewhere; second, prehistoric wild boar that inhabited the Ryukyu Islands had a larger morphological and genetic variability than modern Ryukyu wild boar.