Molossops (Cynomops) paranus (Thomas)

Simmons, Nancy B. & Voss, Robert S., 1998, The mammals of Paracou, French Guiana, a Neotropical lowland rainforest fauna. Part 1, Bats, Bulletin of the American Museum of Natural History 237, pp. 1-219 : 149-153

Molossops (Cynomops) paranus (Thomas)

Figures 59 , 60

VOUCHER MATERIAL: 1 male (AMNH *267535); see table 62 for measurements.

IDENTIFICATION: Molossops paranus , originally described as Molossus planirostris paranus by Thomas (1901b), continues to be recognized as a subspecies of Molossops planirostris by authors (e.g, Koopman, 1978, 1993, 1994). Although Handley (1976) reported specimens identified as Molossops paranus , M. planirostris , and M. greenhalli from the Venezuelan state of Bolívar, he did not comment on the criteria he used to distinguish these taxa. Partial diagnoses and descriptions of the species and subspecies of Cynomops occur throughout the literature, but significant inconsistencies exist among published accounts. Conflicting descriptions of ventral coloration, presence or absence of white hair bases, and degree of development of hair patches on the wings make unambiguous identification difficult. To address this problem, we consulted original taxonomic descriptions, literature accounts of additional material, and examined representative specimens of all of the smaller species to develop working diagnoses for identification. 16

16 The specimens we examined in addition to those from Paracou are: Molossops greenhalli (Mexico: USNM 511543, 523453; Panama: USNM 310264– 310268, 310270–310275, 368108, 396481, 449875; Venezuela: USNM 387745, 517509; Trinidad: AMNH 175326 [holotype], 176285, 207071); Molossops paranus (Panama: AMNH 183868, USNM 317627; Colombia: ROM 41479; Venezuela: USNM 387744; Guyana: ROM 32426, 57337–57338, 57375; Brazil: AMNH 79744–79745); Molossops planirostris (Panama: AMNH 183161, 183863; Venezuela: AMNH 17096– 17097; Brazil: AMNH 37043–37049, 37050–37052, 79725, 79727, 79731, 79733, 93879–93886, 92971, 92753–92755, 94630–94653, 236221; Paraguay: 234455–234459)

Molossops paranus can be distinguished unambiguously from other members of the subgenus Cynomops by external and craniodental traits summarized in table 60. Molossops paranus differs from M. abrasus in size and dorsal fur pattern, and it differs from M. greenhalli in the development of fur patches on the forearm and wing membranes and in many skull dimensions. Finally, M. paranus differs from M. planirostris in coloration of the ventral fur and in the development of fur patches on the forearm and wing membranes.

Another named form that requires consideration is Molossops milleri Osgood , which was based on a single female with a dark venter collected in Peru. Osgood (1914) distinguished milleri from paranus on the basis of size; however, the holotype of milleri is a female and that of paranus a male, so sexual dimorphism could be an alternative explanation. This hypothesis seems supported by our examination of a small series of M. paranus collected at one locality in Guyana by Brock Fenton and his students in 1970. These specimens appear identical in terms of pelage color, development of fur patches on the wings, and other qualitative features. However, the single female (ROM 57337) is much smaller than the two males (ROM 57338, 57375). Measurements of the Guyanan female correspond closely to those of the holotype of milleri , while those of the Guyanan males are very similar to those of the holotype of paranus . Accordingly, we conclude that milleri and paranus represent a single species for which the oldest name is Molossops paranus Thomas.

Our Paracou specimen agrees closely with Thomas’s (1901b) original description of Molossops paranus , and clearly differs from the original descriptions of M. planirostris (Peters, 1865b) and M. greenhalli (Goodwin, 1958) . Two females (CM 64378, 64379) from Grassalco, Surinam, referred to M. greenhalli by Williams and Genoways (1980a, 1980b) and another (AMNH 79745) from near Manaus, Brazil, referred to M. planirostris by Williams and Genoways (1980b) appear to represent M. paranus based on ventral coloration and cranial dimensions.

Although our Paracou specimen represents the first report of Molossops paranus from French Guiana, it may not be the first time that this species has been collected there. Brosset and Charles­Dominique (1990: 544) described a peculiarly dimorphic series of male Molossops collected at one locality, noting that ‘‘when considered separately, the larger and smaller specimens could be classified at first glance as different species.’’ Despite striking differences in cranial morphology and body weight that permitted subdivision of the series into ‘‘type A’’ and ‘‘type B’’ groups, Brosset and Charles­Dominique identified all seven individuals as M. greenhalli . This was justified as follows: ‘‘We place in the same taxonomic unity these dissimilar specimens because in both types, the color of the fur, the shape of the ears, tragus, antitragus, tail, wings, the length of the tooth­rows, the shape and size of the molars are similar.’’

We are unaware of any consistent differences among Molossops greenhalli , M. paranus , and M. planirostris in shape of the ears, tragus, antitragus, tail, wings, length of the toothrows, or shape or size of the molars, and conclude that these features are not useful for distinguishing the smaller species of the subgenus Cynomops . The cranial characters that are useful for distinguishing some species involve dimensions of the skull other than those of the dentition (tables 60, 61). Our examination of Brosset and Charles­ Dominique’s (1990) illustrations and measurements suggest that the smaller form (‘‘type A’’) probably represents M. paranus , while the larger form (‘‘type B’’) probably represents M. greenhalli . A specimen identified as Molossops planirostris was also collected (op. cit.) at the same locality, so more detailed comparisons of this material, which is remarkably extensive for a single­locality sample of Cynomops , may be particularly informative about species limits in the subgenus.

FIELD OBSERVATIONS: Our single specimen of Molossops paranus was caught in a mistnet 18–21 m above a narrow dirt road.

Figures

Fig. 59. Dorsal (A) and ventral (B) views of the skull of Molossops paranus (AMNH 267535; male) from Paracou. Dorsal (C) and ventral (D) views of the skull of the holotype of M. greenhalli (AMNH 175326; male) from Trinidad. Note species differences in size and cranial proportions. Scale bars = 10 mm.

Fig. 60. Lateral views of the skull and lower jaw of (A) Molossops paranus (AMNH 267535; male) and (B) the holotype M. greenhalli (AMNH 175326; male). Scale bars = 10 mm.