Uroderma bakeri, Mantilla-Meluk, 2014

Mantilla-Meluk, Hugo, 2014, Defining Species And Species Boundaries In Uroderma (Chiroptera: Phyllostomidae) With A Description Of A New Species, Occasional Papers of the Museum 325, pp. 1-30 : 10-17

Uroderma bakeri , new species

Holotype. — Adult male, TTU 33358 , body preserved in alcohol, with extracted cranium and mandibles in excellent condition ( Fig. 4 ) and tissues (TK 15288), collected on 25 April 1978 by Margaret O’Connell and Robert J. Baker. Measurements of the holotype and specimens in the type series are presented in Appendix II.

Type locality. — Santa Crucita, in Parque Nacional Guatopo , Miranda, Venezuela, 10º5' N, 66º33'W at an elevation of 2,480 m ( Fig. 5 ).

Type series. —Specimens included in the type series (N=12) consist of seven males (including holotype) and five females from Colombia: adult male ICN 12917 and female ICN 12918 , collected on 28 February 1993 by Juan Manuel Rengifo, in Campo Caño Limón, near Yuca oil well, inside the forest , Arauca; adult male ICN 10881 and adult female ICN 10882 , collected on 22 November 1989 by a field party as part of the Introductory Mammalogy course, Universidad Nacional de Colombia, in Medina, Vereda La Sarza, Quebrada La Sarza , Cundinamarca; adult female ICN 15128 , collected on 2 July 1998 by Cecilia Ramirez, Herly Zuñiga, and Héctor Lancheros, in Vereda Soya, márgen derecho del Río Zaguea, Ubalá, Cundinamarca; adult male ICN 9456 , collected on 29 March 1983 by Group of Advanced Systematics, Universidad Nacional de Colombia, in Fuente de Oro, Km. 9 Road Puerto Limón - Puerto Lleras , Vereda La Esperanza, Finca La Virginia, Meta; adult males ICN 10732 and ICN 10733 and an adult female ICN 10734 , collected on 23 April 1988 by María del Pilar Rivas and Pedro Sanchez Palomino, in San Juan de Arama, Caño La Curia, Meta; adult male ICN 6882 and female ICN 6884 , collected on 7 May 1977 by a field party from the Universidad Nacional de Colombia, in Villavicencio, Finca El Buque , Meta. Two additional specimens of U. bakeri collected on the same night as the U. bakeri holotype were deposited with the Venezuelan authorities that provided the permits, but the museum in which they were archived has not been established .

Distribution. —The species is known from the piedmonts associated with the northwestern Colombian-Venezuelan Orinoco River basin of the Eastern Cordillera of the Colombian Andes and the Cordillera de Mérida and Cordillera del Caribe. This species has been recorded in an elevational range of 500 to 2,500 m ( Fig. 5 ).

Description of the holotype. — Holotype is a general grey color. Dorsal hairs are three-quarters grey with a paler band at base, and venter is paler than dorsum. Uroderma bakeri has a thin, white line along the dorsal midline, well-defined white stripes across the cheek and above the eye, and well-defined black eyebrows on top of the anterior portion of the eyes. Ears have scattered hairs. Borders of the ears, horseshoe, and nose leaf possess a distinctive yellow coloration. Pelage reaches the middle of forearm, with tibia and middle part of the thigh naked. Interfemoral membrane is notched and naked with no hairs on edge. Holotype has a large and massive skull, characterized by a flat lateral profile ( Figs. 4 and 6 ); a broader rostrum; swollen interorbital area at the sutura frontomaxillaris; and a massive dentition, with the typical formula for genus: i 2/2, c 1/1, p 2/2, m 3/3, total 32. Four upper incisors are bilobed and not in contact, with inner incisors larger and located anterior to the lateral ones. Lobes of medial incisors are subequal. Both central and lateral incisors are tilted with tips pointed bucally. Canines are massive, particularly at base, and appear straight from a lateral view. Base of first premolar is triangular. Anterior surface of mesiostyle ( Osborn 1907), or anterior cingular style ( Vandebroek 1961), has a flat appearance in ventral view, and half of its length is in contact with canine. Main cone (paracone) of first premolar is elongated and curved toward labial side. Curvature of first premolar, paracone, allows it to be visible behind canines in a rostral view. First upper premolar is shorter than second premolar and barely surpasses half of length of canine. From a ventral view, tip of posterior cingular style of first premolar is overlapped by mesiostyle of the paraconid of second premolar; however, teeth are not in contact as seen from a lateral view. U. bakeri holotype has an accessory style on first premolar and a wide contact region between second and third molar including the second molar metacone, metaconid, metastyle and its associated crista (teeth nomenclature adapted from Van Valen [1994] and Swindler [2002]).

Diagnosis.— Uroderma bakeri is diagnosed by the following characteristics: large skull (GLS> 23.00 mm); swollen interorbital area at the sutura frontomaxillaris; massive dentition; maxillae deflected into plane of nasals; small crest along suture joining the parietals (sutura sagittalis) that terminates where parietals join the temporal bones (sutura parietointerparietalis); projected edge of squamosal visible from a dorsal view and allowing only a small portion of the tympanic bullae to be viewed; inside the nasal aperture, ventral portion of the nasal maxilloturbinates visible, as well as the septum nasi and part of vomer septum; maxilloturbinates and superior and inferior conchas massive; joining of the nasal bones occurs caudally with respect to the maxillae, nearly forming a straight nasal angle in a lateral view ( Figs. 6 and 7 ).

Comparisons. —The new species can be distinguished from Central American representatives of the U. bilobatum complex (U. b. convexum , U. b. molaris, and U. b. davisi ) by its flat lateral profile ( Figs. 4 and 7 ). Uroderma bakeri lacks the typical deflection of the nasal bones at the interorbital area, which are present in U. b. convexum , U. b. molaris and U. davisi . Uroderma bakeri has a broader rostrum, swollen interorbital area at the sutura frontomaxillaris, a more massive dentition, and a less arched tooth-row than U. b. convexum and U. b. davisi . In contrast with the rostrum of U. bakeri , rostra of U. b. convexum , U. b. molaris, and U. b. davisi are substantially shorter and expand abruptly from the apex to the lachrymal bone edges; therefore, the lachrymal bones are more visible from a rostral view than in U. bakeri . From the eastern South American forms in the U. bilobatum complex (U. b. bilobatum , U. b. thomasi, and U. b. trinitatum), U. bakeri also can be differentiated by its flat lateral profile, swollen interorbital constriction at the sutura frontomaxillaris, and by having a more massive dentition. In addition, in U. bakeri the union of the nasal bones with respect to the maxillae forms a straight nasal angle in a lateral view, whereas in U. b. bilobatum , U. b. thomasi, and U. b. trinitatum, the nasal angle is obtuse ( Fig. 4c ). In U. b. bilobatum , U. b. thomasi, and U. b. trinitatum, the edge of the maxillae (that forms the eye socket) is terminated in a rim that is less distinct in U. bakeri .

All museum voucher specimens in the U. bakeri type series had been misidentified as U. magnirostrum . However, these two species easily can be distinguished by a suite of external and internal characters. Externally, U. bakeri has a dark grey general coat color contrasting the brownish coat of U. magnirostrum . In U. bakeri , rostral stripes are well-marked, whereas in U. magnirostrum rostral stripes are absent or only insinuated. Uroderma bakeri has scattered hairs on the border of the ears, contrasting the naked border of the ears of U. magnirostrum . In addition, the borders of the ears, the horseshoe, and the nose leaf in U. bakeri are distinctive yellow, contrasting the less distinctive yellow borders of the ears and nose leaf of U. magnirostrum . Uroderma bakeri has a wide uropatagium, lacking hair on both dorsal and ventral surfaces, thus differing from the uropatagium of U. magnirostrum , which has scattered hairs on both dorsal and ventral surfaces ( Fig. 6 ). All specimens in the U. bakeri series have long, black hairs on the anterior portion of the eyes forming a brow line. This character was present in only three of 77 U. magnirostrum analyzed (identified based on skull characters, particularly rostrum depth [ Andersen 1908]). These three specimens were collected in two localities from the northern Colombian Amazon at the department of Caquetá (ICN 11342-43 from Montañita, and ICN 12771 from Chiribiquete, department of Caquetá in Colombia). Further analysis is necessary to determine the taxonomic status of these specimens. Internally, U. bakeri and U. magnirostrum share a flattened skull profile. However, the species can be differentiated by the deeper rostrum typical of U. magnirostrum ( Andersen 1908) . In addition, in U. bakeri the nasal aperture has a broader appearance than in U. magnirostrum . The maxilloturbinates and the superior and inferior conchas of U. bakeri are more massive than in U. bilobatum , but less massive than those of U. magnirostrum . In U. bakeri , the nasal septum and the mesethmoid is formed by a thin sheet, not terminated in a shield-like structure, contrasting the wide and massive nasal septum and the shield-like structure associated with the mesethmoid of U. magnirostrum ( Fig. 6 ). In U. magnirostrum the skull is laterally compressed and from a dorsal view, the edges of the squamosal and the tympanic bullae are hidden beneath the parietal. As in other representatives of the genus, the junction of the nasal bones occurs anterior to the junction of the maxilla in U. bakeri . However, in U. bakeri the nasal area, from a lateral view, is divided into two perpendicular planes forming an angle with the vertex marked by the tip of the septum nasi. This angle is more acute in U. bakeri than in other Uroderma ( Fig. 4c ). In U. bakeri , the protrusion of the maxillae allows the roots of the upper incisor to be more noticeable than in other Uroderma . The nasal aperture in U. bakeri is piriform, with the two upper sides deflected internally by a convergent intrusion of the maxillae into the plane of the nasal bones ( Figs. 6 and 7 ); these intrusions are produced by the lateral projections of the nasal septi and are absent in U. magnirostrum where the maxillas are parallel to the nasals ( Figs. 6 and 7 ). In U. bakeri the infraorbital foramen, located above the root of the second premolar, marks the inflexion point of the concave surface of the maxilla bone; in contrast, this inflexion is not noticeable in U. magnirostrum . In U. bakeri , from a rostral view, the lateral sides of the maxillae are deflected or concave and expand into the area of the anterior part of the zygomatic arches; contrasting the flat appearance of the rostrum of U. magnirostrum which extends within a single plane.

Genetic data. — Investigation of the molecular phylogenetic affinities between the new species and other representatives of the genus is beyond the scope of the present work. Hoffmann et al. (2003) reported that the holotype specimen TTU 33358 differed in the mtDNA Cyt b gene (genetic distance of 3.7%) relative to other representatives of the genus .

Karyotype. —The karyotype of U. bakeri is unknown.

Ecology. —The holotype of U. bakeri was collected at the Parque Nacional Guatopo ( Fig. 5 ), located in northern Venezuela, southeast of the city of Caracas. The area is part of the mountainous system of Serranía del Interior. The vegetation corresponds to a tropical hyper-humid pre-montane forest. It is dominated by tree species such as Ochoroma lagopus, Erythrina poeppigiana , Pterocarpus acapulcensis , Tabebuia chrysantha , Bursera simaruba , and Cecropia peltata , and palm trees such as Oenocarpus bataua , Bactris sp. and Asterogyne spicata . The understory also presents a high diversity of plants including Calathea and Heliconia . Epiphytic plants also are well-represented by Araceae , Bromeliaceae , Orquidaceae, and Piperaceae ( Weidmann et al. 2003) .

Morphological characteristics such as larger body size and enlargement of the rostrum at the nasal area, as well as enlarged nasal conchas, may be adaptations of U. bakeri to highland ecosystems. Ecological differentiation also may suggest that the divergence of U. bakeri can be explained by selection and adaptation ( Nosil et al. 2009). Although U. bakeri exists across a wide range of elevational gradients (500-2,500 m), the species inhabits higher elevations than the typical maximum elevational limits of other representatives of the genus.

Etymology.— Uroderma bakeri is named for Dr. Robert J. Baker, who has dedicated his life to the study of a wide variety of aspects of the natural history and evolution of the Neotropical mammalian fauna, in particular to the study of phyllostomid bats. Dr. Baker has used Uroderma as a natural model in several studies since the 1970’s. His ongoing research on Uroderma includes hybrid zones, karyotypic evolution, systematics, population genetics, and niche modeling. The proposed common name is Baker’s tent-making bat.

Figures

Figure 4. Ventral (a), dorsal (b), and lateral (c) profile of the holotype (TTU 33358 ♂) of Uroderma bakeri. Abbreviations: interorbital constriction (IOC); nasal angle (NA); and sutura frontomaxillaris (SFM).

Figure 5. Type locality of Uroderma bakeri in Santa Crucita (red star), Parque Nacional Guatopo, Miranda, Venezuela 10º5'N, 66º33'W, at an elevation of 2,480 m. Yellow stars indicate the collecting localities associated with U. bakeri specimens: 1)Arauca, Campo Caño Limón, near oil drill Yuca, inside the forest (ICN 12917-18); 2) Cundinamarca, Medina, Vereda La Sarza, Quebrada La Sarza (ICN 10881-82); 3) Vereda Soya, márgen derecho del Río Zaguea, Ubalá; 4) Meta, Fuente de Oro, Km. 9 Road Puerto Limón - Puerto Lleras, Vereda La Esperanza, Finca La Virginia (ICN 9456); 5) San Juan de Arama, Caño La Curia (ICN 10732-34); 6) Villavicencio, Finca El Buque (ICN 6882-84). The area highlighted in yellow represents the potential distribution of U. bakeri. Inset: Photo of the collecting site, taken by Robert J. Baker the day of the capture of the holotype (25 April 1978).

Figure 6. Comparative images of skin (a and b) and frontal view of skulls (c and d) ofUroderma magnirostrum (left) and U. bakeri (right). Abbreviations: conchas (Co); NS (septum nasi); maxilla bone (Mx); interorbital constriction (IOC); deep rostrum (DR); shallow rostrum (SR); face lines (FL); and hairy uropatagium (HU).

Figure 7. On the left: comparisons of cranial external characters between Uroderma bakeri (top) and U. convexum (center); detail of nasal aperture of U. bakeri showing the intrusion of the maxilla (Mx) into the plane of the nasals (N) (bottom). On the right: skull profiles of U. magnirostrum (TTU 28496); U. bakeri (TTU 33358); U. bilobatum thomasi (TTU 341912); and U. convexum (TTU 39139) (top to bottom).