Chiroderma Peters, 1860

Garbino, Guilherme S. T., Lim, Burton K. & Tavares, Valéria Da C., 2020, Systematics of big-eyed bats, genus Chiroderma Peters, 1860 (Chiroptera: Phyllostomidae), Zootaxa 4846 (1), pp. 1-93 : 16-20

Genus Chiroderma Peters, 1860

Synonyms:

Chiroderma Peters, 1860: 747 . Type-species Chiroderma villosum Peters, 1860 , by monotypy.

Mimetops Gray, 1866: 117 . Listed in the synonymy of Chiroderma ; being a nomen nudum.

Chirodesma Thenius, 1989: 113 (not verified). Incorrect spelling of Chiroderma W. Peters, 1860 . Distribution. Chiroderma is in western, eastern, and southern México, Central America ( Guatemala, Belize, Honduras, El Salvador, Nicaragua, Costa Rica, and Panamá), Lesser Antilles (Guadeloupe, Marie-Galante, Monserrat, Saint Kitts and Nevis), Trinidad and Tobago, and South America ( Venezuela, Guyana, Suriname, French Guiana, Colombia, Ecuador, Perú, Bolivia, Paraguay, and Brazil south to the state of Santa Catarina) ( Fig. 7 ).

Diagnosis. Chiroderma is a genus of small to large-sized fruit and seed-eating bats (total length of head and body 50–93 mm, length of forearm 34–58 mm, body mass 11–42 g; Tables 7 and 8). Dorsal fur dense, with long guard hairs, standing out above the underfur covering the body, and especially conspicuous on the cephalic region. Dorsal fur varies from buff to dark brown or dark gray; individual hairs with three well-defined bands, with the middle band always wider and paler than basal and terminal bands. Ventral pelage varies from pale gray to plumbous gray. The median dorsal stripe conspicuous or faint; may be absent in some C. villosum . Dorsal stripe begins at interscapular region and extends to the base of uropatagium. Four facial stripes present in most individuals, and may be bright and wide or faint and narrow. Tip of the spear of noseleaf may be notched. Horseshoe of noseleaf with free margins along its entire extension. Ears relatively small and round. Forearm densely furred along the proximal ⅔ of its length. Wing membranes, i.e., propatagium, chiropatagium, plagiopatagium, and uropatagium, are dark and opaque, except for the pale, translucent membrane between digits II and III of the dactylopatagium. Uropatagium relatively well-developed, extending posteriorly to the level of the knees; densely furred dorsally along ⅔ of its length. Plagiopataium inserts at the metatarsus. Tail absent. Calcar shorter than foot.

Skull with a conspicuous notch at the region of the nasal bones, which are extremely reduced ( Fig. 8 ). Orbital region relatively large; distinct postorbital processes. Frontonasal region relatively straight, in lateral view (neither concave nor convex; Fig. 8 ). Hard palate long, extending posteriorly close to glenoid fossa. Basioccipital pits shallow or absent. Dental formula: I 2/2, C 1/1, P 2/2, M 2/2. First upper incisors (I1) conic in cross-section, elongated with simple tips (not bilobed), and more than twice the crown size of the second upper incisors (I2). First upper premolar (P3) and canine (C) in contact; diastema between P3 and second upper premolar (P4). First and second upper molars (M1 and M2) with approximately the same occlusal area, or M2 with slightly larger area than M1; M2 triangular in occlusal view, with protocone distally placed and level with centrocrista. Hypocone absent in both M1 and M2; small hypoconal basin present in M1. With cranium and mandible in occlusion, there is a lateral gap bordered by the upper canine (C), first upper premolar (P3), and the two lower premolars (p2 and p4; Fig. 9 ).

Coronoid process of mandible tall, its height approximately level with the tip of lower canine (c). Angular process conspicuous, projecting ventro-posteriorly in relation to the horizontal ramus of the mandible. Mandibular condyle relatively high, level with or slightly above tooth row. First lower premolar (p2) close to canine, the two teeth usually in contact; p2 shorter in height and length than second lower premolar (p4), ranging from approximately ¼ to ⅔ the height of p4. Diastema between p2 and p4. Second lower molar (m2) is the largest mandibular tooth and approximately twice the mesiodistal length of the first lower molar (m1). Well-developed metaconid, entoconid, protoconid, and hypoconid in m2. There is a fifth cusp between the hypoconid and entoconid, that we identify as the hypoconulid, following Garbino & Tavares (2018a). Discrete morphological comparisons among the species of Chiroderma recognized in this study are summarized in Table 9, and the descriptive statistics of the species is summarized in Tables 7 and 8.

The species of Chiroderma for which the karyotype is known, i.e., C. doriae , C. improvisum , C. salvini , C. trinitatum , and C. villosum , have a chromosomal complement of 2n = 26 and FN = 48, a subtelocentric X-chromosome, and a submetacentric or subtelocentric Y-chromosome ( Baker 1967, 1973; Baker & Hsu 1970; Baker & Genoways 1976; Varella-Garcia & Taddei 1985).

Figures

FIGURE 7. Collecting localities of the Chiroderma specimens analyzed in this study. The localities are compiled in the gazetteer (Appendix 1).

FIGURE 8. Dorsal, ventral, and lateral views of skull and lateral view of the mandible of Chiroderma villosum (USNM 408644) from San Juan, Amazonas, Venezuela.

FIGURE 9. Lateral view of skull and mandible in occlusion for A) Chiroderma salvini (ROM 99703), B) Chiroderma scopaeum (TTU 110649), C) Chiroderma d. doriae (TTU 99569), D) Chiroderma villosum (USNM 560607), and E) Chiroderma improvisum (ROM 126002).