Thylamys tatei (Handley, 1957)

Giarla, T. C., Voss, R. S. & Jansa, S. A., 2010, Species Limits And Phylogenetic Relationships In The Didelphid Marsupial Genus Thylamys Based On Mitochondrial Dna Sequences And Morphology, Bulletin of the American Museum of Natural History 2010 (346), pp. 1-67 : 49-50

Thylamys tatei (Handley, 1957)

SYNONYMS: None.

DISTRIBUTION: According to Solari (2003), who examined more material than we have seen, Thylamys tatei is known only from the Peruvian department of Ancash and from the Lomas de Lachay in the northern part of the department of Lima, between 300 and 3000 m above sea level. This species is not known to occur sympatrically with any other congener.

MORPHOLOGICAL DIAGNOSIS: Body pelage tricolored (abrupt line of transition from darker middorsal to paler lateral coloration present); ventral pelage with narrowly continuous median streak of self-white (or whitish) fur from chin to anus, flanked by broad lateral zones of gray-based hairs; plantar pads of manus separate, surrounding a concave central palmar surface, and with well-developed dermatoglyphs; manual claws long, extending well beyond fleshy apical pads of digits; tail longer than combined length of head and body (LT/HBL X 100 5 113%; N 5 9), usually with pale tip (whitish above and below for distal 2–18 mm); prehensile ventral surface of tail tip well developed. Nasal bones usually very long, extending posteriorly well behind lacrimals; lacrimal foramina concealed from lateral view inside orbit; infraorbital foramen above P3 or above P3/M1 commissure; nasolabial fossa shallow; supraorbital margins almost always rounded or squared; maxillary fenestrae almost always absent; unworn crown of second upper incisor (I2) consistently larger than crown of I3; stylar cusp C variably present or absent on M1, usually absent or indistinct on M2; metaconule absent on M3.

COMPARISONS: Comparisons between Thylamys tatei and other currently recognized species of the Elegans Group are provided in the preceding accounts. Mea-

TABLE 21 Measurements (mm) of Sequenced Specimens of Thylamys sp. and T. tatei from Peru a

surement data from sequenced specimens of T. tatei and specimens of related but unnamed forms from the Peruvian departments of Arequipa, Ayacucho, and Lima are provided in table 21.

REMARKS: Originally described as a valid species, tatei was subsequently listed as a synonym of Thylamys elegans by Gardner (1993). Although our results are obviously consistent with recent inferences from molecular and morphological studies that tatei and elegans are distinct species ( Meynard et al., 2002; Palma et al., 2002; Solari, 2003; Braun et al., 2005), other taxonomic problems remain. Foremost among these is the identification of specimens from the Peruvian provinces of Lima (e.g., MVZ 119913, 137585) and Huancavelica (e.g., MVZ 136249) that resemble tatei in having broad lateral zones of graybased ventral fur but which lack some of the diagnostic craniodental traits of tatei and have divergent mtDNA sequences. Although Solari (2003) identified these as pallidior (as discussed above), they cluster with tatei in our phylogenetic analyses.

SPECIMENS EXAMINED (N 5 13): Peru — Ancash, Chasquitambo (USNM 302915 [holotype], 302916), Huaráz (FMNH 81443), 1 km N and 12 km E Pariacoto (MVZ 155503–135512).