Taxonomic status of the ricefield rat Rattus argentiventer (Robinson and Kloss, 1916) (Rodentia) from Thailand, Malaysia and Indonesia based on morphological variation

WA Museum Records and Supplements | Updated 8 years ago

ABSTRACT – Comparison of cranial and external characters of 212 rice field rats Rattus argentiventer (Robinson and Kloss 1916), by univariate and multivariate statistical analyses, was carried out on specimens from Thailand, Malaysia, and Indonesia (Sumatra, Kalimantan, Java, Bali, Lesser Sunda, Sulawesi and Irian Jaya). These comparisons indicate that ricefield rats from Thailand to Irian Jaya fall into four groups: a Java group (Thailand, Malaysia, Sumatra and Java), a Bali-Sulawesi group (Bali, Sulawesi, Lombok, Sumbawa, Adonara, Sangeang, Rinca, Flores, Lembata, Aim, Timor and Tanimbar Islands); a Sumba group (Sumba Island) and a Kalimantan group (Kalimantan Island). The specimen from Irian Jaya was placed in the Java group. The taxon from Kalimantan is described as a new subspecies, R. a. kalimantan.

The multiple regression analysis indicated that while skull, dentary, dental, and external characters of the ricefield rat do not exhibit sexual dimorphism, age or interactions between islands, sex and / or age does influence some characters.