Taxonomy of the Neotoma albigula-Group of Woodrats in Central Mexico

E. Raymond Hall, Hugh H. Genoways
1970 Journal of Mammalogy  
Study of specimens collected from critical localities since 1944 reveals that: Neotoma montezumae and N , leucodon zacatecae are indistinguishable from earlier named taxa; N . Zatifrms is a subspecies of an earlier named taxon; and N. palatinu, previously known from only one specimen and thought by some mammalogists to be merely an aberrant individual of Neotoma, albigula, is a species distinct from N . albigula as Goldman tentatively decided when he named it 64 years ago. In the narial
more » ... the narial passage, the partition formed by the vomer that extends well behind the hard palate as a swordlike projection is present in all specimens of N . palatina, but the projection is not present in N . albigula. Because of uncertainty about the taxonomic status of woodrats in MBxico for which the names Neotoma latifrons, Neotoma montezumae, Neotornu palatina, and Neotoma leucodon zacatecae had been proposed, specimens that would be expected to be helpful in removing the uncertainty have been saved by collectors from The University of Kansas Museum of Natural History on several occasions in the past 20 years. Our conclusions after studying these specimens and other pertinent materials are set forth below. Catalogue numbers, unless otherwise indicated, are those in The University of Kansas Museum of Natural History. Measurements are in millimeters. Neotoma albigula leucodon Merriam Comparison of the holotypes and all other available specimens of N. a. zacatecae Goldman and N, a. leucodon (see list of specimens beyond) permits us to see in specimens used by Goldman (1910:38) all but one of the cranial features relied on by him to differentiate between the two subspecies. The one feature not seen is the greater arching across the anterior roots of the zygomata in zacatecae. The other cranial features relied on by Goldman are seen to be individual variations now that many more specimens than he had in 1910 are available to us. These features are decurved rostrum, longer frontals, heavier maxillary arm of the zygoma, and smaller upper incisors. The dusky instead of grayish or whitish upper lip thought by Goldman (loc. cit.) to distinguish zacatecae from leucodon does not do so in five specimens of zacatecae from 13 mi. N Jalpa, Zacatecas; the upper lips of four are dusky and in one white. Neither does the darker color of back and sides ascribed to zacatecm by Goldman (loc. cit.) appear to be distinctive when taking variation with season and age into account. For example, two of five adults of leucodon from 2 mi. ESE Trancoso are as dark as four of five specimens of zacatecae from 13 mi. N Jalpa (only 15 miles south of the type locality of zacatewe). Furthermore, a specimen from 3 mi. SW Jalpa is as pale as the palest specimen (36875) of leucodun available to us. JOURNAL OF MAMMALOGY Vol. 51, No. 3 Neotoma albigula leucodon Neotoma palatina FIGS. 2-3.-Vomer bone in two species of woodrats: N e o t m albigula leucodon, KU 105854 ad., 3 mi. E Totatiche, 5600 ft., Jalisco; Neotoma palatina, KU 99038 ad., 6 mi. NE Bolaiios, Jalisco. Slightly diagramatic representation of bones in a sagittal section (enclosed by heavy black line) of the skull of two species showing posterior extent of vomer (diagonal lines), with transverse section of vomer above posterior margin of M2 at lower left. Areas with broken lines denote cut or broken surfaces of bones.
doi:10.2307/1378390 fatcat:fcxkdvpl5vccjbl7zemw5qz4pa