GBIF Taxonomic Backbone & Wikipedia Registry Profile
Description and Comparisons. Dorsal pelage varies from pale brown to dark brown. Most of the 38 specimens examined had pale brown pelage (84.2 %, n = 32), whereas dark brown pelage was found in 15.8 % (n = 6). Individually, dorsal hairs are tricolored, with a dark brown base, buff middle band, and light to dark brown tips. The medial dorsal stripe was present in all specimens (n = 34), but was weakly developed in 5.8 % of the sample (n = 2). Usually, the dorsal stripe extends from the interscapular region to the posterior extremity of the body, but in 10 specimens the stripe originated in the region immediately posterior to the nape. Both pairs of facial stripes are bright and wide (interocular stripe> 1.7 mm). The tragus and base of the ears are yellowish, as are the anterior and posterior margins of the ears close to the base. The remainder of the ear is brown. The spear of the noseleaf has a simple tip and is brown, except for the lateral margins of the horseshoe, which are whitish. The dimensions of the skull of C. scopaeum are similar to those of C. villosum, and there is also some overlap between the large C. scopaeum and the small C. doriae vizottoi and C. salvini (Tables 7 and 8). In dorsal view, the brain case is round and less massive than in C. salvini. Approximately ⅓ of the length of the nasal notch extends behind the anterior margin of the orbits. The post-orbital constriction is relatively wide (Table 7); post-orbital processes are small and pointed. A sagittal crest was unambiguously present in 32 of the 38 specimens (84.2 %), but not detected in 2 (5.2 %), or ambiguous in 4 (10.5 %). The posterior palatine process was absent in 32 of the 38 analyzed specimens (83.8 %), but small or vestigial in the remaining 6 (16.2 %). Out of 35 specimens, 30 (85.7 %) had convergent I 1 s, with the tips touching each other; whereas, 5 had both incisors separated along their entire length. The P 3 is approximately oval in occlusal outline and is not in contact with P 4. The M 2 has well defined main cusps, but lacks a posterolingual cingulum. The lower canine has a relatively low crown, below the level of the coronoid process in lateral view. The anterior cingulum of the lower canine projects rostro-medially and is visible in lateral view (Fig. 17). The p 2 is small, approximately ¼ of the height of p 4; and is longer than tall and does not touch p 4. Compared with C. salvini, C. scopaeum can be distinguished by its smaller size, usually paler dorsal pelage (varying from pale brown to dark brown). C. scopaeum has a relatively broader post-orbital constriction (Fig. 12), and rostro-medially projected cingula of lower canines (Fig. 17). From C. villosum, C. scopaeum can be differentiated by its bicolored noseleaf and spear having a simple tip; paler ear margins; shorter nasal notch (in villosum the notch reaches the post-orbital processes); shorter orbits (in villosum the anterior margin is in line with the middle of P 4); I 1 s with convergent tips (usually parallel in villosum); relatively short lower canine (in villosum the tip of the lower canine is at approximately the same level as the coronoid process); and absence of a frontal gap when cranium and mandible are in occlusion (in villosum there is a frontal gap delimited by C, I 1 – 2, and i 1 – 2). The subspecies C. d. vizottoi differs from C. scopaeum by having pale buff pelage, and larger size (Table 7). The p 2 of C. d. vizottoi is larger, about ½ to ⅔ of the height of p 4, while in C. scopaeum, p 2 is approximately ¼ the height of p 4. Geographic Variation and Phylogeography. A clade, here identified as scopaeum, contains six specimens of Chiroderma, of which five were analyzed morphologically (Fig. 16). The two specimens from México (TTU 109703 and TTU 110649) are phenotypically similar to the taxon we defined here as Chiroderma scopaeum, whereas specimens from Panamá (LSUMZ 25470), El Salvador (TTU 62462), and Guatemala (ROM 99703) have the diagnostic characters of Chiroderma salvini. The specimens morphologically diagnosed as salvini that nested in the scopaeum clade may represent a case of incomplete lineage sorting (ILS), a relatively common phenomenon in recently-diverged taxa (Maddison & Knowles 2006). To test the ILS hypothesis between C. salvini and C. scopaeum, we recommend increasing the genetic sample of Chiroderma from western México, and obtaining additional genomic information such as single nucleotide polymorphisms. Also, it is important to note that no specimens, morphologically diagnosed as scopaeum, are nested in the salvini clade, which contains sequences from Central and South American specimens. Subspecies. C. scopaeum is monotypic.
