Geocapromys brownii

MAMMALIAN SPECIES No. 201, pp. 1-5, 7 figs. Geocapromys brownii. By Sydney Anderson, Charles A. Woods, Gary S. Morgan, and W. L. R. Oliver Published 8 April 1983 by The American Society of Mammalogists Geocapromys Chapman, 190 I man. CONTEXT AND CONTENT. Order Rodentia, Suborder Hystricognathi, Superfamily Octodontoidea, Family Capromyidae, including the genera Cap romys , Geocapromys, Hexolobodon, Plagiodontia, and Isolobodon. It is not desirable at this time to divide the Capromyidae into subfamilies. The genus Geocapromys includes four extinct and two living species (Fig. 1). Three extinct species, G. columbianus, G. pleistocenicus, and G. megas, are known from fossil deposits in Cuba, whereas G. thoracatus has become extinct on Little Swan Island only within the last 30 years. The two living species are G. ingrahami from East Plana Cay in the southern Bahamas and G. brownii. Geocapromys brownii (Fischer, 1830) Jamaican Hutia Capromys brownii Fischer, 1830:589. Type locality "Jamaica" by original designation. Capromys brachyurus Hill, in Gosse, 1851:471. Type locality [John Crow Mountains, Portland Parish,] "Jamaica," by original designation. Capromys (Geocapromys) brownii Chapman, 1901:320. Geocapromys brownii Allen, 1917:8. First use of present name combination. CONTEXT AND CONTENT. Context in generic account above. No subspecies are currently recognized in Geocapromys brownii. DIAGNOSIS. Within Geocapromys, G. brownii differs from the two other recent species, G. thoracatus and G. ingrahami in: 1) larger size; 2) darker coloration; 3) much shorter tail (shorter than hindfoot, rather than equal to or longer than hindfoot); 4) relatively smaller ears; 5) strong sagittal crest and weak temporal crests; 6) anterior inflation and posterior constriction of frontals; 7) enlarged jugal fossa and prominent jugal spine; 8) anteriorly broadened zygomatic arches; 9) and deeply-pigmented yellow-orange incisors. The species of Geocapromys are morphologically distinct and should be recognized as a separate genus, differing from all remaining species of Capromys (sensu stricto) in: 1) shorter tail, less than 25% of total length; 2) shorter, finer fur; 3) reduced first digit on forefoot; 4) tendency toward anterior convergence of toothrows resulting in contact between bases of alveoli of right and left P4 (see Miller, 1929, pI. 1, Fig. lA); 5) location of posterior end of root capsule dorsal and lateral to anterior half of outer border of alveolus of P4, instead of anterior to P4; 6) broad, vertically- or posteriorly-oriented superior zygomatic root of maxilla; 7) labial inclination of occlusal surface of cheekteeth: 8) and presence of a small third re-entrant angle on anterolingual surface of P4 (anteroflexid). GENERAL CHARACTERS. Geocapromys brownii is about the size of a cottontail rabbit, but more heavily built. Adults weigh 1,000 to 2,000 g. Jamaican hutias have a compact appearance because of their relatively large head and short ears, neck, legs, and tail (Fig. 2). Upperparts are dark reddish-brown to blackishbrown, underparts are uniform dusky brown. The fur is dense and coarse, generally about 20 to 25 mm long and with a few longer hairs interspersed. Each hair is blackish and has a ring of bright bay or golden brown near the tip, imparting a brindled appearance to the pelage. The feet are clothed in short and stiff blackish hair, c:>~6 ~ 0 "' 7~tIo5 ~ D D 2 (::1 3 ~ 1 ~ FIGURE 1. Map of part of the Caribbean area, showing the distributions of the genus Geocapromys: 1, Geocapromys brownii on Jamaica; 2, Geocapromys thoracatus on Little Swan Island; 3, Cayman Brae, location of unidentified specimens of Geocapromys; 4, Cuba, location of three extinct species of Geocapromys; 5, G. ingrahami ingrahami on East Plana Cay; 6, G. i. abaconis, now extinct on Great Abaco; 7, G. i. irrectus, now extinct on Crooked Island. The scale represents .1,000 km. Geocapromys Chapman, 1901 :314. Type species Capromys brownii Fischer. Originally a subgenus of Capromys. Synodontomys Allen, 1917:5. Type species C. columbianus Chap- the soles are black and roughened with rasp-like warts. The pollex is a rudimentary tubercle but has a blunt nail;' the hallux is set far back and separable from the other toes (Fig. 3). The ears are small with a dense covering of short, fine hairs (Fig. 4). In addition, there are two tufts of longer hairs on the inner dorsal margin of the ear, one above and behind the external meatus and one directly posterior to the meatus on the ventrolateral margin. The tail is short, stiff, and tapers abruptly (Fig. 5). It is scaly and has thick, short, bristly fur which is black on upper surface of tail and grayish-brown below. The tail averages more than 20 mm shorter than the length of the hindfoot, whereas in G. thoracatus the tail and hindfoot are approximately equal in length and in G. ingrahami the tail is considerably longer than the hindfoot. The difference in tail length between these three species appears to be correlated with the number of caudal vertebrae: G. brownii averages only 15 caudals, G. thoracatus has 17, and G. ingrahami has 19. The cranium of Geocapromys brownii is considerably larger than the crania of the two other recent species (Fig. 6). Cranial measurements average 15-20% larger than the next largest species, with almost no overlap. The frontals are noticeably inflated medial and anterior to the orbits and form a prominent convexity in the dorsal profile of the skull. Posteriorly, in the region of the frontoparietal suture, the frontals are strongly constricted. Coupling these two features, the frontals are considerably broader anterior to the supraorbital processes than posterior to them, in contrast to other species in the genus. Most individuals of this species have a moderate to strongly-developed sagittal crest formed by the convergence of weak temporal crests. The lambdoidal crests and paroccipital processes are also well developed. The zygomatic arches are broad anteriorly, positioned deep below the orbits, and have a large lateral jugal fossa and prominent jugal spine. The superior zygomatic root of the maxilla is broad and inclined posteriorly. The auditory bullae are not inflated and the internal nares are not constricted. The upper toothrows show a tendency toward anterior convergeI).ce, although not to the degree seen in other species of Geocapromys. The mandible is robust and has a deep symphysis (Fig. 7). The masseteric crest is well developed, originating opposite the first MAMMALIAN SPECIES 201 2 FIGURE 4. Drawing of head, showing long vibrissae and short ears (Pocock, 1926). molar, curving laterally, and ending posteriorly in the prominent spinous angular process. The coronoid process is triangular with the tip curved posteriorly. The articular surface of the condyloid process is elongated anteroposteriorly and the postcondyloid process is strong. The dental formula is i Ill, cOlO, pIll, m 3/3. The inc (...truncated)