Nyctinomops mbopicuare Barquez, Tomasco, Sánchez, Boero, and Díaz, sp. n., 2023

Barquez, Rubén M, Tomasco, Ivanna H, Sánchez, R Tatiana, Boero, Lourdes, Rodriguez, Alejandro Daniel & Díaz, M Mónica, 2023, A new species of bat in the genus Nyctinomops Miller, 1902 (Chiroptera: Molossidae) from Misiones, Argentina, Journal of Mammalogy 104 (5), pp. 1062-1071 : 5-7

Nyctinomops mbopicuare Barquez, Tomasco, Sánchez, Boero, and Díaz, sp. n.

Holotype.— Adult male ( CML 14170 ) preserved as skin, skull, and postcranial skeleton ( Figs. 4 and 5 ), collected on 18 November 2019 by Rocío Tatiana Sánchez (RTS), Alejandro Rodriguez, and Lourdes Boero (field number RTS 361). External and craniodental measurements are listed in Table 2 .

Type locality.— Reserva Natural Osununú, peñón, a orillas del río Paraná ( Fig. 1A ), San Ignacio department, Misiones province, Argentina, 27°16 ʹ 43.53 ″ S; 55°34 ʹ 34.77 ″ W, elevation 100 m.

Paratype.— Adult male ( CML 14171 ) preserved as skin, skull, and postcranial skeleton, from the type locality, collected on 18 November 2019 by Rocío Tatiana Sánchez, Alejandro Rodriguez, and Lourdes Boero (field number RTS 363). External and craniodental measurements are listed in Table 2 .

Other specimens.— Six adult females and four adult males were captured at the type locality and released on 18 November 2019. Five females were pregnant.

Distribution.— Known only from the type locality.

Etymology.— The name mbopicuare comes from the Guaraní language, in recognition of the ‘Pindoty-I’ Guaraní community that inhabits the area, and means ‘bat of the cave,’ mbopi = bat and cuaré = cave.

Diagnosis.— The new species is clearly distinguishable from all other species in the genus Nyctinomops by the following combination of characters: dorsal coloration reddish brown (= Hazel color of Ridgway; Figs. 4 and 6 ), ventrum paler; rostrum, wings, and uropatagial membranes dark brown; body size medium; with forearm lengths from 45.0 to 47.5 mm (n = 12 specimens, six males and six females measured; 47.4 and 47.5 mm in the holotype and paratype, respectively); greatest length of skull 18.7 and 18.8 mm; dorsal hairs short (~ 4.5 mm) and tricolored, ventral hairs longer (~ 5.1 mm) and strongly tricolored; lambdoidal crests continuous; occipital bone slightly extended beyond the lambdoidal crests in dorsal view; basisphenoid pits are shallow; posterior border of the third upper molar is at the same level as the palatal border ( Fig. 5 ).

Description.— A small- to medium-sized bat (GLS 18.7– 18.8 mm; FA 45.0– 47.5 mm). Nyctinomops mbopicuare , as are other species of Nyctinomops , is characterized by an upper lip with deep folds or wrinkles; long, slender facial bristles; ears joined at their bases over the top of the head, and extending forward beyond the tip of the muzzle; antitragus higher than wide, and a tragus that is small and rectangular. The second phalange of the fourth digit is shorter than 5 mm (2.3 and 2.9 mm, taken on dry skins). Dorsal coloration reddish brown (= Hazel color of Ridgway 1912; Fig. 4 ), with venter paler; dorsal hairs (~ 4.5 mm) shorter than ventral hairs (~ 5.1 mm); dorsal hairs dirty white for one-third of their length, followed by a narrow paler band and a darker reddish brown tip; ventral hairs paler than those on the back (especially in the center of the chest and belly), strongly tricolored with dirty white bases, reddish brown middle band, and beige (= Cream Buff color of Ridgway 1912) tips; ventrally, pelage extends onto the plagiopatagium; rostrum and ears dark brown, as are the wing and interfemoral membranes; dorsal margin of each ear has a row of reddish brown hairs; hairs inside the ears are also reddish brown; short, scattered hairs on the forearm, and on the ventral surface of the uropatagium, especially along the tail; tail is long (55 mm in both specimens); feet have thickened toes bordered with long, curved, and spatulate hairs.

The skull is elongated, especially the rostrum, which is expanded at the level of the strongly marked lacrimal processes; anterior palatal emargination is narrow, as typical of the genus; interorbital region is somewhat tubular, expands anteriorly, and intermediate in size between that of N. macrotis and N. laticaudatus ; sagittal crest is low and lambdoidal crests are continuous across the skull; basisphenoid pits are shallow; at the ventral junction rami are small and posteriorly directed, but clearly evident processes are markedly better developed than in the other two species from Argentina ( Fig. 7 ); angular process is less displaced outward, and coronoid process is wider and projects outward in comparison to these characters in N. laticaudatus ( Fig. 7 ).

Dental formula: I 1/2, C 1/1, P 2/2, M 3/3 = 30. Upper incisors are long, narrow, parallel, and slightly curved in lateral view; canines are long; first upper premolar is small compared to the second, which is at least three times larger, and its crown is rounded and the tooth is separated from the second premolar by a narrow gap; second premolar is well-developed and molariform ( Fig. 5 ); first two upper molars are subequal in size and have four notable commissures; third molar is slightly smaller, has only three commissures; third commissure is well-developed and as long as the second; posterior border of the third upper molar is at the same level as the posterior border of the palate (anterior margin of the mesopterygoid fossa); four lower incisors are small, bilobed, imbricated, and completely fill the space between the canines; lower canine is long, about twice the height of the lower first premolar; second lower premolar is higher than the first; all three lower molars are structurally identical with well-developed cusps and four commissures; first and second lower molars are subequal while the third molar, although almost equal in length, is narrower.

Comparisons.— Nyctinomops mbopicuare is clearly distinguishable from N. macrotis by smaller size, the latter being the largest species in the genus ( Figs. 2 and 7 ; Table 2 ) with a forearm length greater than 55 mm (less than 50 mm in N. mbopicuare ) and a greatest length of skull greater than 22 mm (less than 19 mm in N. mbopicuare ). Basisphenoidal pits in N. mbopicuare are shallow and the processes on the ventral symphysis between rami are well-developed; whereas basisphenoidal pits are deep in N. macrotis and the processes on the ventral symphysis between rami are barely perceptible ( Fig. 7 ). Nyctinomops mbopicuare cannot be confused with N. femorosaccus , a species that is known only from the United States, Mexico, and Guatemala, and characterized by a membranous pouch that extends from the distal third of the femur to the middle of the tibia, forming a pocket between the leg and the interfemoral membrane, and not found in the other species. Also, the posterior border of the palate terminates behind the third upper molar. Compared to N. aurispinosus , N. mbopicuare is smaller, although the two are similar in having tricolored dorsal hairs; differences are also found in the skull and length of the upper toothrow, which is longer than 7.9 mm in N. aurispinosus versus shorter than 7 mm in N. mbopicuare . Nyctinomops laticaudatus is the most similar in size ( Figs. 2 and 7 ; Table 2 ), but its dorsal coloration is dark brown with slightly bicolored hairs, as opposed to reddish brown with tricolored hairs in N. mbopicuare . Other external and cranial differences distinguishing N. mbopicuare from other Nyctinomops are presented in Table 3 .

Other species collected in the reserve.— We captured Artibeus lituratus , Carollia perspicillata , Chrotopterus auritus , Glossophaga soricina , Sturnira lilium ( Phyllostomidae ), and M. nigricans ( Vespertilionidae ) during our sampling in the area. Glossophaga soricina was collected at an abandoned house, where some C. perspicillata were also observed.

Figures

Fig. 4.—Dorsal and ventral views of the skin of the holotype of Nyctinomops mbopicuare (CML 14170). Scale bar = 10 mm.

Fig. 5.—Lateral view of the skull and mandible (top), dorsal (bottom left), and ventral (bottom right) views of skull of the holotype of Nyctinomops mbopicuare (CML 14170). Scale bar = 5 mm.

Fig. 1.—A) Map of ecoregions and known distribution points for the three species of Nyctinomops from Argentina: N. laticaudatus (triangles), N. macrotis (circles), and N. new sp. (star); B) roost of Nyctinomops new sp. in a deep crevice in the rock cliffs; C) strip of land between the rock wall and the river bank, where the mist nets were placed.

Fig. 6.—Frontal viewof aliving specimenofNyctinomops mbopicuare.

Fig. 7.—Top row: dorsal view of skulls of the three species of Nyctinomops known from Argentina: N. laticaudatus (CML 1913); N. mbopicuare (CML 14170); and N. macrotis (CML 1082). Bottom row: ventral view of the mandible of N. laticaudatus (CML 1913); N. mbopicuare (CML 14170); and N. macrotis (CML 1082) showing the difference in development of the process located at the symphysis. Scale bar = 5 mm.

Fig. 2.—Scatter plot of the two principal components of eight cranial measurements of two specimens of the new species of Nyctinomops (crosses) compared with the four known species of the genus: triangles = N. laticaudatus; dots = N. aurispinosus; star = N. femorosaccus; squares = N. macrotis; crosses = N. new sp.