''Paucidentomys'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

rodent Rodents (from Latin , 'to gnaw') are mammals of the Order (biology), order Rodentia ( ), which are characterized by a single pair of continuously growing incisors in each of the upper and Mandible, lower jaws. About 40% of all mammal specie ...

s of a type commonly known as shrew-rats which was discovered in 2012 in a remote rainforest on the

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian Ocean, Indian and Pacific Ocean, Pacific oceans. Comprising over List of islands of Indonesia, 17,000 islands, including Sumatra, ...

n island,

Sulawesi Sulawesi ( ), also known as Celebes ( ), is an island in Indonesia. One of the four Greater Sunda Islands, and the List of islands by area, world's 11th-largest island, it is situated east of Borneo, west of the Maluku Islands, and south of Min ...

. The genus is

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ...

, consisting of the species ''Paucidentomys vermidax'', or the edented Sulawesi rat. The

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

name may also be translated to its other common name "few-toothed worm-eating rat", referring to the fact that they have only two teeth and may live exclusively on a diet of

earthworm An earthworm is a soil-dwelling terrestrial invertebrate that belongs to the phylum Annelida. The term is the common name for the largest members of the class (or subclass, depending on the author) Oligochaeta. In classical systems, they we ...

Description

''Paucidentomys vermidax'' is larger than '' Melasmothrix naso'', '' Sommeromys macrorhinos'' and ''

Tateomys macrocercus The long-tailed shrew rat (''Tateomys macrocercus'') is a species of rodent in the family Muridae. It is found only in Central Sulawesi, Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania ...

'', similar in size to '' Tateomys rhinogradoides'', smaller than ''

Rhynchomys soricoides The Mount Data shrew-rat (''Rhynchomys soricoides'') is a species of rodent in the family Muridae. It is found only in the Philippines. References

* Rhynchomys Mammals described in 1895 Taxa named by Oldfield Thomas Taxonomy articles c ...

'' and substantially smaller than species of ''

Echiothrix ''Echiothrix'' is a genus of rodent in the family Muridae endemic to Sulawesi, Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian Ocean, Indian and Pacific Ocean, Paci ...

''. The face is more elongate than that of any other Sulawesi shrew-rat, but similar in this regard to '' Rhynchomys''. It has a very long

rostrum Rostrum may refer to: * Any kind of a platform for a speaker: **dais **pulpit ** podium * Rostrum (anatomy), a beak, or anatomical structure resembling a beak, as in the mouthparts of many sucking insects * Rostrum (ship), a form of bow on naval ...

(relative to other Sulawesi shrew-rats), small eyes, large ears, a soft

pelage A fur is a soft, thick growth of hair that covers the skin of almost all mammals. It consists of a combination of oily guard hair on top and thick underfur beneath. The guard hair keeps moisture from reaching the skin; the underfur acts as an ...

and a long, thick, hairy and

dorsoventral Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position pro ...

ly bicoloured tail.

Unique dentition

''Paucidentomys vermidax'' is the only known rodent with no

molars The molars or molar teeth are large, flat tooth, teeth at the back of the mouth. They are more developed in mammal, mammals. They are used primarily to comminution, grind food during mastication, chewing. The name ''molar'' derives from Latin, '' ...

, which is an adaptation to its diet which may be exclusively

s (it appears to be a specialist

vermivore Vermivore (from Latin vermi, meaning "worm" and vorare, "to devour") is a Zoology, zoological term for animals that primarily eat worms (including annelids, nematodes, and other worm-like animals). Animals with such a diet are known to be vermivor ...

based on the stomach contents of one individual). Moreover, rather than gnawing

incisors Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, wher ...

, this animal has

bicuspid The premolars, also called premolar teeth, or bicuspids, are transitional teeth located between the canine and molar teeth. In humans, there are two premolars per quadrant in the permanent set of teeth, making eight premolars total in the mou ...

upper incisors, which is also unique among the more than 2,200 species of rodents. The upper incisors are short with an anterior cusp and slightly inferior posterior cusp; these cusps are connected by a sharp, concave cutting edge at the

lateral Lateral is a geometric term of location which may also refer to: Biology and healthcare * Lateral (anatomy), a term of location meaning "towards the side" * Lateral cricoarytenoid muscle, an intrinsic muscle of the larynx * Lateral release ( ...

margin of the tooth. The

pterygoid Pterygoid, from the Greek for 'winglike', may refer to: * Pterygoid bone, a bone of the palate of many vertebrates * Pterygoid processes of the sphenoid bone ** Lateral pterygoid plate ** Medial pterygoid plate * Lateral pterygoid muscle * Medial ...

plate is absent. The

dentary In jawed vertebrates, the mandible (from the Latin ''mandibula'', 'for chewing'), lower jaw, or jawbone is a bone that makes up the lowerand typically more mobilecomponent of the mouth (the upper jaw being known as the maxilla). The jawbone ...

is long and delicate, lacking significant muscle attachment points. The lower incisors are unicuspid, procumbent, sharp and delicate. Its

dental formula Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, it is the characteristic arrangement, kind, and number of teeth in a given species at a given age. That is, the number, type, and morpho-physiology ...

is .

Distribution

''Paucidentomys vermidax'' is known from Mount Gandangdewata and

Mount Latimojong Latimojong (Indonesian: Gunung Latimojong), also known by its peak name Rantemario, is a mountain located in the province of South Sulawesi, Sulawesi, Indonesia. At , it is the highest mountain on the island, although some sources state Mount Ra ...

in Sulawesi, Indonesia.

Etymology

The generic name combines the Latin ''paucus'' (few) with ''dentis'' (tooth) and the Greek ''mys'' (mouse) in reference to the lack of molars. The epithet is a hybrid of ''vermi'' (worm) and ''edax'' (devourer), in reference to the animal's diet.

References

{{Taxonbar, from1=Q18643215, from2=Q148559 Muridae Endemic fauna of Indonesia Rodents of Sulawesi Mammals described in 2012 Old World rats and mice