Scotophilus borbonicus (É. Geoffroy, 1803 )

Goodman, Steven M., Jenkins, Richard K. B. & Ratrimomanarivo, Fanja H., 2005, A review of the genus Scotophilus (Mammalia, Chiroptera, Vespertilionidae) on Madagascar, with the description of a new species, Zoosystema 27 (4), pp. 867-882 : 871-872

Scotophilus borbonicus (É. Geoffroy, 1803)

Vespertilio borbonicus É. Geoffroy, 1803: 55 . Scotophilus borbonicus – Jentink 1888: 184.

REMARKS

This species was described by Geoffroy (1803) from the “île de Bourbon” ( La Réunion) based on two individuals sent to Paris by a M. Macé. Hill (1980) discusses the historical details of this material. The two specimens were apparently divided between the MNHN and the Musée des Pays-Bas in Leiden, which would be later called the Rijksmuseum van Natuurlijke Historie. Neither of these specimens has been located in the MNHN, nor are they referred to by Rode (1941) in his catalogue of type specimens in that collection. However, one of the specimens was registered in the museum’s catalog ( Moutou 1982). In Jentink’s (1888: 184, entry c) catalogue of bats in the Leiden Museum it is mentioned under the heading Scotophilus borbonicus Geoffroy , “Individu adulte monté, figuré dans la Mammalogie de Temminck, T. II, Pl. XLVII, fig. 7. Bourbon. Du voyage de M. Macé”. It is almost without question that this specimen (RMNH 28508) is one of the two animals É. Geoffroy used in the original description of this species, and, based on this logic, Hill (1980) designated it as the lectotype of S. borbonicus .

After the inspection of collections and queries at numerous natural history museums, including the MNHN and Muséum d’Histoire naturelle of Saint-Denis ( La Réunion), as well as literature citations (e.g., Hill 1980; Moutou 1982; Robbins et al. 1985), the lectotype in the RMNH appears to be the only known extant specimen in the world of S. borbonicus from La Réunion. It is in very poor condition. The mounted skin has partially extended wings and associated membranes are brittle, partially broken, and the distal portions frayed. An incision made in the lower abdomen, presumably when it was prepared as a mounted skin, is only partially closed. Further, the pelage is foxed, but certain aspects of the original coloration can still be clearly discerned. The dorsum of the specimen is a reddish-brown and the ventrum a dull whitish ( Table 1). In Geoffroy’s (1803: 55) original description it is noted, “pelage marron en dessus, blanchâtre en dessous”, which closely fits with our judgment of this specimen’s current coloration. The associat- ed skull is partially broken, with the cranium largely shattered – rendering it impossible to make numerous measurements.

As mentioned earlier, Dorst (1947) noted the occurrence of S. borbonicus on Madagascar, presumably based on the Grandidier material in the MNHN. Of the three small Malagasy Scotophilus specimens in that collection, one (MNHN 1976.420) from Sarodrano has a distinctly reddish-brown dorsum and light-colored ventrum. This specimen was collected in 1868 and has been stored in alcohol over the intervening years, and thus it is not unexpected that the natural pelage coloration has become washed-out. Even given the poor condition of the lectotype, these two specimens (RMNH 28508 and MNHN 1976.420) showed considerable resemblance in basic pelage coloration and comparable cranial and dental structures ( Tables 1-5), and we are inclined to identify MNHN 1976.420 as S. borbonicus . However, until new material from La Réunion of S. borbonicus is uncovered in museum collections or collected in the wild, final determination of MNHN 1976.420 will not be possible. At the present time we refer this specimen to S. cf. borbonicus . The tragus of the MNHN specimen is rounded towards the apex and has a simple peduncle attachment ( Fig. 2 ). In Figure 3 we have illustrated the skull and mandible of MNHN 1976.420 for future comparative purposes.

One striking aspect of the history of moderate to small Scotophilus species on Madagascar is that two different sea caves near the village of Sarodrano, presumably exactly at or close to where Grandidier collected his specimens, and the nearby village of Saint-Augustin have been extensively surveyed over the past few years by our field teams and no example of this genus has been found. While it is true that much of our capture work has been conducted at cave entrances, a site type Scotophilus rarely use for their day-roosts, we have surveyed synanthropically-living bat species in the village of Saint- Augustin. Further, the late R. L. Peterson also captured bats in the sea caves of Sarodrano in 1967 and no Scotophilus was collected. Even more exceptional is that amongst the two specimens of Scotophilus obtained by Grandidier in the Sarodrano region are two different species – S. cf. borbonicus and a second species that is new to science and described below. Although the specimen labels indicate that these individuals were captured in caves, it is possible that they were obtained in the nearby village of Sarodrano, which would have been a series of thatched houses during the period of Grandidier’s visit, a construction style Scotophilus frequently inhabit ( Kingdon 1974).

Considerable work has been conducted over the past century of the bats of the Mascarene Islands, particularly La Réunion. The reputed presence of S. borbonicus on Mauritius Island is erroneous ( Cheke & Dahl 1981), and there is no evidence of a Scotophilus on the Comoro Islands ( Louette et al. 2004). Given that members of this genus are often associated with man-made shelters and are relatively easy to catch, the absence of any s u b s e q u e n t r e c o r d s o f S. b o r b o n i c u s o n L a Réunion is rather notable ( Cheke & Dahl 1981; Moutou 1982). This would imply that this species is exceptionally rare, difficult to capture, part of an extralimital migratory population, or even extinct. Given that currently available material is insufficient to properly diagnose S. borbonicus , the possibility cannot be completely eliminated that the provenance of the two Macé specimens is incorrect or that these captured individuals were vagrants to La Réunion. It has been suggested that borbonicus might be conspecific with African leucogaster (Hill in Cheke & Dahl 1981). The same point might hold for MNHN 1976.420 in that it may not be a representative of a resident population on Madagascar. In a recent action plan for microchiropteran bats, Hutson et al. (2001) list- ed S. borbonicus as occurring on La Réunion and Madagascar and considered it to be critically endangered.

Figures

FIG. 2. — Right ear and tragus of Scotophilus from Madagascar; A, holotype of S. tandrefana n. sp. (UADBA 46923); B, S. cf. borbonicus (MNHN 1976.420); C, paratype of S. tandrefana n. sp. (MNHN 1984.433). There is some variation in the sickle-shaped tragus of S. tandrefana n. sp., but the attachment peduncle of the tragus is a slightly complex structure, rather than a simple attachment stalk as in S. borbonicus (É. Geoffroy, 1803).

FIG. 3. — Dorsal, ventral and lateral views of adult crania and mandible of Scotophilus cf. borbonicus (MNHN 1976.420; greatest skull length = 19.0 mm) from Sarodrano.