Identification of species in Soricidae and Muridae on Okinawa-jima Island based on their hair morphology

Abstract

Hair morphology such as hair length and width, medulla width, and external morphology of scales and medulla were examined to establish the identification key of hairs of two species of Soricidae and four species of Muridae for the purpose of food habit analysis of alien carnivores on Okinawajima Island. All species had straight guard hair, and three murid species had one more type of guard hair. Only one type of under hair was observed in common to all species. The straight guard hairs were divided at 10 mm of an average hair length. They could be classified to species level based on the structure of the scale and the medulla. The other type of guard hair observed in the three murid species was identified by hair length and width. Furthermore, the three species could also be identified by the external morphology and the structure of medulla. Based on these characteristics, we created an identification key using hair morphology for six species. This study clarified that guard hair is suitable for species identification. Although it is difficult to identify species using only one characteristic, a comprehensive assessment makes identification possible.