Waiomys mamasae

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Waiomys mamasae
Systematics
Family : Long-tailed mice (Muridae)
Subfamily : Old World Mice (Murinae)
Tribe : Rattini
Echiothrix group
Genre : Waiomys
Type : Waiomys mamasae
Scientific name of the  genus
Waiomys
Rowe, Achmadi & Esselstyn, 2014
Scientific name of the  species
Waiomys mamasae
Rowe , Achmadi & Esselstyn , 2014

Waiomys mamasae is a small rodent from the family of long-tailed mice (Muridae) that occurs on the Indonesian island of Sulawesi . Waiomys mamasae is the only species of thegenus Waiomys which is monotypical . The scientific generic name is composed of the word 'wai' (= water) from the indigenous language Mamasa Toraja and the Greek word for mouse ('mys') and indicates the semi-aquatic way of life of the species. The species epithet mamasae refers to the local population, who call the animal the 'water rat' in their language. The holotype of the species is an adult male that was caught on May 12, 2012 while swimming in the shallow water of a fast-flowing mountain river.

features

The total length of the holotype is 288 mm, with the tail accounting for 159 mm, which is about 25% longer than the head-torso length . The weight was 64 g. Compared to body length, Waiomys mamasae's head is the shortest of all Sulawesi shrew rats. The infraorbital foramen is large and leaf-shaped , the magnum foramen large. The eyes are small (⌀ ~ 2 mm) and almost invisible in the head fur; the short, 11 mm long ears are very hairy inside and out. The snout, flattened at the top and bottom, is wide. The incisors are narrow; their enamel is colored orange. There are three molars on each half of both jaws . The whiskers are moderately dense and stiff. Their base is black, the end is unpigmented. Most whisker hairs are 5 to 25 mm long, a few are up to 40 mm long and thus extend over the auricles.

The gray-brown fur on the back is soft, fine and extremely dense, the light gray peritoneum is similar. The tail has white hairs on its underside. The hair of the undercoat is shorter than 10 mm, gray at the hair root and has light brown tips. The sparsely standing, about 10 mm long outer hair is colored gray proximally and dark brown distally and protrudes only a few millimeters above the undercoat. The hair of the back fur protrudes almost vertically from the skin and can be brushed in any direction. The peritoneum is soft and dense and consists of the undercoat and a fine, white outer hair that rises almost 5 mm above the undercoat. The base of the undercoat hair is dark gray, the distal quarter light gray. The color of the hair on the back as well as the hair on the stomach and head is relatively uniform. The peritoneum forms two conspicuous white spots (⌀ approx. 10 mm) on the rear part above the hind legs and it extends about 15 mm on each side of the tail base. The gray-brown fur on the back extends to the fingers of the front paws and on the long hind legs to the ankles. The hind paws have no hypothenar , but a large thenar on the sides .

Like the shrew rats found in the mountains of New Guinea (the genus Baiyankamys with two species) and the Monckton swimming rat ( Crossomys moncktoni ), Waiomys mamasae also differs from the lowland species by its soft, gray fur and small ears.

Systematics

A phylogenetic analysis shows that Waiomys mamasae is closely related to the small Sulawesi shrew rat ( Melasmothrix naso ) and to the long- snouted Paucidentomys vermidax , which was first described in 2012.

literature