248.

Long-footed Tree Mouse

Lorentzimys nouhuysii

French: Rat de Nouhuys / German: Neuguinea-Baumspringmaus / Spanish: Ratén arboricola de pies largos

Other common names: New Guinean Jumping Mouse

Taxonomy. Lorentzimys nouhuysii Jentink, 1911,

“Bivak II (+x 400 m.),” Noord (= Lorentz River), Province of Papua, West-Papua (= Irian Jaya), New Guinea.

Genus Lorentzimys, in the past listed as a single clade or as sole member of the Lorentzimys division, is currently classified within tribe Hydromyini, where it may belong to a clade ( Pogonomys + Lorentzimys) close to Macruromys, Anisomys, Chiruromys, Hyomys, and Pogonomys . Some earlier authors recognized highland form “ alticola ” as a distinct species or subspecies. Further undescribed species of Lorentzimys are presumed to occur in Papua New Guinea in the Muller Range, in Hindenburg Wall region, and on Huon Peninsula; a morphological overview of museum holdings by K. P. Aplin, published in 2015 (in biodiversity assessment by S. J. Richards and N. Whitmore), indicates that as many as 5-6 species may be represented in the genus. A careful revision of this genus is needed. Currently treated as monotypic.

Distribution. New Guinea, including Central Cordillera, Torricelli Mts, Adelbert Range, and Huon Peninsula (Finisterre Range).

Descriptive notes. Head-body 55-90 mm, tail 110-125 mm, hindfoot 19-22 mm, ear 14-19 mm; weight 10-23 g. The Long-footed Tree Mouse has a very long, but not prehensile, tail with tufted tip. Head is short and broad, with small ears tapering to a rounded point; ears are at least twice as long as they are broad and have a blunt point, a feature shared with Philippine genus Musseromys, which also has relatively long, narrow hindfeet. Hindfeet are elongated, with claws on each finger. Forefeet have four fingers with sharp, arched claws, butfifth has a short, flattened nail. Whiskersare fairly long (c.65 mm). Pelage is relatively short and crispy, that of highland form “ alticola ” long and soft. Upperparts are reddish brown or grayish, and underparts buff or grayish white. Head is slaty around the eyes and ears; cheeks and underside of neck are whitish (grayish in “ alticola ”). Feet are white. Tailis light fuscous with a tuft of fine hairs at tip. Highland form “ alticola ” differs from other populations in a suite of characters (hairs of tail black, instead of white; ears less wedge-shaped; different cheek color). Skull has large braincase, wide zygomatic arches, and relatively large bullae. Incisors are proodont, and (as in Mus) with a notch.Teeth are extremely small. Females have six mammae. Chromosomal complement has 2n = 46, FN = 52.

Habitat. Primary and secondary tropical forest, at elevations of 80-2700 m. The Longfooted Tree Mouse may prefer open or disturbed forest with abundant low shrubbery, rather than mature forest where trunks rise uninterrupted to canopy.

Food and Feeding. l.ong-footed Tree Mice are omnivorous, eating insects, plant material, and fungi.

Breeding. The Long-footed Tree Mouse makes nests in Pandanus (Pandanaceae) and similar trees. It also makes moss nests among rocks. One female carried two embryos. Litters are probably of 2—4 young.

Activity patterns. The Long-footed Tree Mouse is presumably both diurnal and nocturnal. Its morphology suggests that it runs through the branches rather than climbing.

Movements, Home range and Social organization. A nest found in a tree fern ( Asplenium, Aspleniaceae) on a tree limb c.2 m aboveground contained two females which, when disturbed, ran from the epiphyte and sought shelter; they did not hop or jump, nor use the tail as a prehensile organ, but this species can run very fast over branches.Several individuals may live together in one nest. In 1990, T. F. Flannery found a group consisting of an adult male, four subadult males, and an undetermined animal in a moss nest among rocks in Telefomin area of Papua New Guinea.

Status and Conservation. Classified as Least Concern on The IUCN Red List (as L. nouhuysi). The Long-footed Tree Mouseis locally common. In view ofits wide distribution and presumed large population,it is unlikely to be declining at nearly the rate required to qualify for listing in a threatened category. If future taxonomic work splits the species, there may be some restricted taxa warranting a threatened listing.

Bibliography. Aplin & Kale (2011), Boitani et al. (2006), Fabre et al. (2012), Flannery (1995b), Heaney et al. (2009), Helgen & Helgen (2009), Laurie & Hill (1954), Leary, Singadan, Menzies, Wright & Aplin (2016), Menzies & Dennis (1979), Musser & Carleton (2005), Richards & Whitmore (2015), Rowe, Achmadi & Esselstyn (2014, 2016b), Rowe, Reno et al. (2008), Tate (1951), Watts & Baverstock (1994b).