Taxonomy and appearance
The Finlayson's squirrel has a head-and-body length of about and its tail is about long. There are currently 16 recognised subspecies. Additional subspecies are sometimes recognised. For example, some authorities recognise ''C. f. floweri'', while others consider it a Synonym (taxonomy), synonym of ''C. f. bocourti'' (as done in the following colour description). The subspecific name of ''C. f. boonsongi'' commemorates Thai zoologist and conservationist Boonsong Lekagul. The pelage colour in this species is extremely variable and the subspecies are often defined by this feature. For example, ''C. f. finlaysonii'' (Nominate subspecies, nominate) is overall whitish, ''C. f. albivexilli'', ''C. f. boonsongi'', ''C. f. germaini'' and ''C. f. nox'' are overall blackish (first with white tail-tip, second occasionally with white underside, face and feet), ''C. f. annellatus'' is overall rufous with a light band at the base of the tail, ''C. f. bocourti'' is whitish below with highly variable colour of the upperparts (whitish, grey, blackish, Olive (color), olive-brownish or reddish), ''C. f. cinnamomeus'' is overall reddish with a dark mid-back, ''C. f. ferrugineus'' is reddish-brown, ''C. f. harmandi'' has brownish upperparts, orange-red underparts and light grey tail, ''C. f. menamicus'' is reddish or orangish, often has greyish legs and flanks, and sometimes a white belly, and ''C. f. sinistralis'' has grizzled upperparts, reddish underparts and reddish tail with a pale band at the base.Boonkhaw, Phadet, Prayoon, Umphornpimon, Kanchanasaka, Budsabong, Hayashi, Fumio, Tamura, Noriko (2017). Colour polymorphism and genetic relationships among twelve subspecies of Callosciurus finlaysonii in Thailand. ''Mammalian Biology – Zeitschrift für Säugetierkunde 85'', 6–13. Undescribed taxon, Unnamed populations also remain (for example, a population in central Laos is shiny black with red tail and shoulder/chest region) and even within described subspecies there are often some individual variations. As currently defined, Finlayson's squirrel may comprise more than one species. ''C. f. ferrugineus'' has been treated as a separate species. A Genetics, genetic study of the 12 subspecies in Thailand, including 7 from the mainland and 5 from islands, found that they belonged in six clades, which often were separated by water (large rivers in the mainland and the sea for the islands). The study also revealed that the mitochondrial DNA of this species compared to the closely related Pallas's squirrel is not monophyletic. A subsequent study recommended that, to maintain monophyletic species, ''flavimanus'' and ''griseimanus'', which traditionally are recognized as being subspecies of Pallas's squirrel in southeastern Indochina (central and southern Vietnam, adjacent parts of Cambodia and southern Laos), should be considered part of Finlayson's squirrel. The study also found that ''flavimanus'', as traditionally defined, actually consists of at least two clearly separate Lineage (evolution), lineages, both part of Finlayson's squirrel.Behavior
Like other squirrels of its genus (the "beautiful squirrels", ''Callosciurus''), Finlayson's squirrel is normally a canopy-dweller, feeding mainly on fruit. Field evidence suggests that it has the usual form of dichromacy, dichromatic mammalian color vision, which may enable it to discriminate ripe from unripe fruits.Tamura, N., Fujii, Y., Boonkeow, P., & Kanchanasaka, B. (2015). Colour vision and food selection of ''Callosciurus finlaysonii'' (Sciuridae) in tropical seasonal forests. ''Journal of Tropical Ecology, 31'', 449–457.References
External links