Grayides

Grayides are a proposed, extinct clade of small nocturnal mammals known only from fragmentary late Miocene to early Pliocene fossils found in temperate forests of Eurasia and North America. The name comes from reports of grey fur in some specimens. Because the material is sparse, grayides are regarded as a provisional grouping in many treatments.

Anatomy and appearance: Based on jaw fragments and limb bones, grayides are estimated to be 8–18 cm long, with a slender tail and dense grey fur. They likely had large eyes and a pointed snout, consistent with a nocturnal insectivorous lifestyle. Limb features suggest climbing ability and versatility in leaf litter.

Ecology and behavior: They probably foraged in leaf litter and understory vegetation, feeding on insects and small invertebrates. The fossil record indicates the use of tree hollows or shallow burrows for nesting. Reproduction is inferred to be by small litters with some parental care.

Taxonomy and significance: The phylogenetic position of grayides is debated. Some analyses place them as a basal placental lineage, others as a stem group near the base of eutherians. The fragmentary material limits conclusions, but grayides are cited in discussions of mammalian diversification in the Neogene.