Lawomys, Veatch & Fabre & Tocheri & Sutikna & Saptomo & Musser & Helgen, 2023

Lawomys gen. nov.

urn:lsid:zoobank.org:act:C0D7C82A-47C6-4944-91A0-1587CC7B449B

Diagnosis: A murine of large body size with mandibular features unlike all known endemic murines on Flores or in the Indo-Pacific region ( Figs 4 View Figure 4 and 5 View Figure 5 ). It is distinguished by the following features: a large mandible (measurable specimens are ca. 42–43 mm in length without the incisor and ca. 18–19 mm in height); prominent condyloid and angular processes with a broadly concave posterior margin between them; a condyloid process joint that extends along the entire dorsal ridge; a small coronoid process; large mental and mandibular foramina with a weakly developed retromolar fossa ridge; the alveolar sheath enclosing most of the lower incisor is encased entirely within the body of the dentary and extends from the anterior portion of the dentary to the base of the condyloid process; the molars are tiny relative to the size of the mandible; the first lower molar is the largest tooth and is anchored by two roots; the lower first molar is egg-shaped and resembles a basin in which the buccal and lingual edges of the cusps are smooth and continuous creating a bowl-like structure, the anterior lamina being the most reduced; its occlusal morphology is very simple with low, blunt cusps forming three distinct transverse laminae; the first lamina contains reduced anterolingual and anterolabial cusps that coalesce when worn; the protoconid and metaconid are somewhat coalesced but retain identifiable morphologies within the second laminae; the hypoconid and entoconid are distinctive from one another yet blend together to form a “bow-tie” shaped occlusal surface when worn; there is also a greater separation between the second and third laminae where a noticeable yet shallow cleft separates the two compared to the first and second; the second lower molar is anchored by two large roots but is markedly shorter than the first molar yet similar (slightly smaller) in breadth; its occlusal surface is simple like the first molar with a basinlike structure creating a smooth edge around the tooth; the protoconid and metaconid are identifiable within the first lamina as are a morphologically simple hypoconid and entoconid within the second lamina; the third lower molar is likely anchored by two fused roots (based on the shape of the alveolus as this molar has not yet been recovered) ( Fig. 5 View Figure 5 ); the lower incisor is large relative to the size of the mandible (measurable specimens have breadths between ca. 1.7–2.6 mm at the alveolus) and long, extending internally through the ramus and terminating at the condyloid process; the incisor is also wide and deep, especially at the alveolus; enamel forms most of the ventrolabial surface of the incisor (⅓ to ½ of the lingual surface), the outer surface of which is smooth and lacks any anterior grooves or distinctive features; the incisal wear pattern is lengthy and continuous with no “lip” or abrupt termination.

Type species. Lawomys rokusi sp. nov., a new species from Flores, Indonesia.

Included species. The type species only.

Etymology. The genus name combines the word Lawo, from the Manggarai language meaning “rat”, with the suffix— mys, Greek for mouse or rat. Manggarai is an Indigenous language spoken in western Flores, including at Liang Bua, the type locality.