Abrocoma Waterhouse, 1837

Taraborelli, Paula A., Sassi, Paola L., Dacar, MARíA A., Moreno, Pablo & Ojeda Abstract, Ricardo A., 2015, Abrocoma schistacea (Rodentia: Abrocomidae), Mammalian Species 47 (921), pp. 45-50 : 45-46

Abrocoma Waterhouse, 1837

Abrocoma Waterhouse, 1837:30 . Type species Abrocoma bennettii Waterhouse , fixed by Tate (1935:384).

Habrocoma Wagner, 1842:5 . Unjustified emendation of Abrocoma Waterhouse, 1837 .

CONTEXT AND CONTENT. Order Rodentia , suborder Hystricomorpha , infraorderHystricognathi,familyAbrocomidae. The family Abrocomidae ( Rodentia : Hystricognathi ) contains 2 genera, Abrocoma Waterhouse, 1837 with 8 species ( A. bennettii Waterhouse, 1837 , A. boliviensis Glanz and Anderson, 1990 , A. budini Thomas, 1920 , A. cinerea Thomas, 1919 , A. famatina Thomas, 1920 , A. schistacea Thomas, 1921 , A. uspallata Braun and Mares, 2002 , and A. vaccarum Thomas, 1921 — Patton et al. 2015) and Cuscomys Emmons, 1999 with 2 species ( C. ashaninka Emmons, 1999 and C. oblativus Eaton, 1916 — Patton et al. 2015). The species C. oblativus was formerly classified as A. oblativus but has been reassigned ( Emmons 1999). C. oblativus was considered likely extinct by Thomas (1920), it was only known from remains found in 1912, buried alongside humans in ancient Inca tombs at the Machu Picchu ruins (Woods and Kilpatrick 2005; Pacheco et al. 2008). However, photos of a rodent taken at the ruins in late 2009 appear to be images of C. oblativus ( Castillo 2009) . A key to the 8 currently recognized species of Abrocoma follows (modified from Patton et al. 2015):

dorsal color dark brown; ventral color pale (whitish); mastoid islands distinctly small (<16% of mastoid breadth)...................... Abrocoma boliviensis

Body size medium to large; tail not long (<75% head and body length); dorsal color dark to pale (grayish); ventral color drab (dark grayish) to pale; mastoid islands medium to large (> 20% of mastoid breadth).................2

2. Body size large (head and body length> 200 mm); tail moderately long (about 71% head and body length); hind foot> 32 mm; dorsal and ventral color dark (brownish); interorbital region broad (breadth> 8 mm);

1. Body size medium (head and body length about 175 mm); tail Fig. 1. —Adult male Abrocoma schistacea from El Leoncito National Park proportionately long (about 81% head and body length); (San Juan Province, Argentina). Photograph by Paula Taraborelli (2006).

mastoid bullae small (width <23% condylobasilar length)......................... Abrocoma bennettii

Body size large to medium (head and body length <200 mm); tail moderate in length (60–70% head and body length) or short (<55%); hind foot length shorter (<31 mm); dorsal color paler brownish-gray to gray; ventral color dark to pale gray; interorbital region narrow to medium (breadth <7.8 mm); mastoid bullae medium to large (width> 27% of condylobasilar length).......................... 3

3. Dorsal color pale gray; tail very short (35–42% head and body length); tail weakly bicolored above and below; interorbital region broad (breadth> 7.5 mm); mastoid bullae inflated (width> 27% of condylobasilar length)......................... Abrocoma cinerea Dorsal color gray with brownish overtones; tail of medium proportions (53–68% head and body length); tail moderately to strongly bicolored; interorbital region narrow (breadth <7.0 mm); mastoid bullae moderately to well inflated (width 25–29% of condylobasilar length)..... 4

4. Hind feet long (> 30 mm); mastoid islands large (> 23% of mastoid breadth)............................... 5 Hind feet shorter (<30 mm, on average); mastoid islands medium (<23% of mastoid breadth)............... 6

5. Body size large (head and body length about 200 mm); dorsal color darker (brownish gray); tail moderately bicolored; maxillary toothrow proportionately short (<22% condylobasilar length); posterior border of palate pointed; upper incisors large and broad............ Abrocoma budini Body size medium (head and body length <180 mm); dorsal color paler (grayish brown); tail strongly bicolored; maxillary toothrow proportionately long (24% of condylobasilar length); posterior border of palate rounded; upper incisors small and narrow............... Abrocoma uspallata

6. Tail relatively short (<53% head and body length, on average); upper incisors small and narrow; bullar inflation great (width> 28% condylobasilar length). Abrocoma famatina Tail relatively long (> 58% head and body length); upper incisors large and broad; bullar inflation medium (width <27% condylobasilar length)...................... 7

7. Dorsal color grayish drab; mesopterygoid fossa wide; upper incisors orthodont.............. Abrocoma schistacea Dorsal color gray; mesopterygoid fossa narrow; upper incisors opisthodont................ Abrocoma vaccarum