Eumops bonariensis (W. Peters, 1874)

García, Franger J., Ochoa-G, José, Poma-Urey, José L., Miller, Bruce W., Falcão, Fábio C. & del Valle Alvarez, Martín Roberto, 2024, Expanding the knowledge of the bat fauna of the Brazilian Caatinga: new geographical records of molossid bats (Chiroptera, Molossidae) for the Chapada Diamantina region, with taxonomic notes, ZooKeys 1210, pp. 333-371 : 333-371

Eumops bonariensis (W. Peters, 1874)

Summary of captures.

One female ( CMARF 2121).

External measurements and weight.

TLB: 108.00, TL: 43.00, LHL: 7.00, EL: 18.00, W: 10.00.

Morphological description.

Dorsal fur is chocolate brown, with the basal portion of hairs paler than the tips. Ventral and dorsal coloration show slight contrast, with the hairs around the neck and shoulders darker than the rest (Fig. 4 ). Upper lips are slightly wrinkled. The upper border of the narial region is surrounded by small and obtuse warts. Small hairs cover internarial ribs. Ears broad, rounded, and joined in a common point. The upper border of ears with pointed and fleshy warts. The inner keel of the ears reaching the antitragus, not extending beyond the posterior part of this structure. Antitragus long and semicircular. The tragus is slightly squared, with the upper extreme narrower, giving the appearance of an obelisk shape.

The skull is broader across the rostrum, with an evident depression near the mastoid bone; the braincase is deeper (globular shape), and the lateral region is curved (Fig. 5 ). Interparietal bones are not elongated and not visible in the lateral view of the skull. The sagittal crest is less developed than the lambdoidal crest. Upper incisors with divergent tips projected forward, forming an angle with the canines of 45 °. Upper canines and first premolars in contact. The second upper premolar is protocone-wide and robust (Fig. 5 ). The third upper molar has a well-developed commissure. The posterior part extends beyond the maxillary bone (Fig. 6 ). The palate does not extend beyond the level of the third upper molars (Fig. 6 ). Mesopterygoid fossa with basisphenoid pits deep, narrow anteriorly and broader posteriorly, with an oval shape (Fig. 5 ). Rib between basisphenoid pit wide. Incisive foramen diminutive. The mandible is slender, with an articular process wider and more developed than the condylar and coronoid processes. Lower incisors bilobed. Values of some cranial measurements of the collected female and the data for the same variables provided by other studies are shown in Table 1 .

Identification.

Externally, the forearm length (> 40 mm) and the shape and depth of the basisphenoid pits (deep, narrowing anteriorly, and broader posteriorly) separate this species from Eumops hansae Sanborn, 1932 ( Eger 2008). Compared to the closest morphologically similar species, Eumops patagonicus O. Thomas, 1924 , and Eumops delticus O. Thomas, 1923 , E. bonariensis can be differentiated from E. patagonicus by being larger in some external and cranial measurements, including the lengths of the forearm and skull. Additionally, the extension of the internal keel of the ears, not reaching the anterior antitragus area in E. patagonicus , is a discreet characteristic that can help differentiate E. patagonicus from E. bonariensis ( Díaz et al. 2021) . However, Bernardi et al. (2009) identified an individual as E. patagonicus with an internal keel reaching the middle region of the antitragus. With respect to E. delticus , cranial morphological characters are provided in the Discussion to aid in distinguishing both species.

Figures

Figure 4. Females of Eumops bonariensis (CMARF 2121; A) and Eumops delticus (CMARF 2122; B) showing the body coloration, the antitragus shape, and the extension of the internal ear keel that reaches the posterior part of the antitragus (indicated by the white bar).

Figure 5. Dorsal, ventral, and lateral views of the skulls of two species of Eumops collected in the Caatinga, northeastern Brazil. A, C (upper) - Eumops bonariensis (CMARF 2121) B, C (lower) - Eumops delticus (CMARF 2122). White arrows indicate the morphological differences between both taxa, highlighted in the species’ account. Scale bar 5 mm.

Figure 6. Enlarged views (not to scale) of some cranial and dental characteristics of Eumops bonariensis (A, C) and Eumops delticus (B, D). The discontinuous red lines and white arrows indicate the differences in palatal and maxillary lengths between both species, respectively.