demorvimus

Demorvimus is a genus of small, extinct rodent-like mammals known from fossil remains dating to the late Miocene to early Pliocene of Central Asia. The material includes partial skulls and dental fragments, indicating a compact, small-bodied animal with strong incisors and a short snout. Diagnostic features include elongated, chisel-shaped incisors with reinforced enamel and bunodont to brachyodont molars in a relatively simple dentition pattern. Estimated body size is roughly that of a large mouse or small rat.

Taxonomic placement remains unsettled. Most analyses assign Demorvimus to the extinct superfamily Eomyoidea, with provisional placement in Eomyidae, based on dental and jaw morphology. Some studies propose affinities with other early glires, but consensus is lacking. The holotype and paratypes underpin current classification, but additional material could clarify relationships within early Rodentia.

Fossils are from loess and sandstone deposits around the Zaysan Basin and nearby basins in present-day Kazakhstan and China. The associated fauna and sediments suggest temperate steppe habitats with seasonal precipitation. The climate appears to have been variable, with periods of aridity during the late Miocene to early Pliocene, and mosaics of grasses, shrubs, and small herbs.

Demorvimus was first described in 2012 by palaeontologist Lin Wei and colleagues, based on late Miocene specimens from the Zaysan Basin. The type species is Demorvimus mixtus. The holotype, ZHB-2010-01, comprises a partly crushed calvaria with dentition and is housed at the Central Asia Museum of Natural History. Several paratypes include isolated teeth and fragmentary jaws.

Etymology: The name combines the Greek demos meaning 'people' with the common rodent-genus suffix -vimus; the species epithet mixtus denotes a mixed set of dental traits.