Glauconycteris superba Hayman, 1939

Tungaluna, Guy-Crispin Gembu, Cakenberghe, Victor Van, Akawa, Prescott Musaba, Akaibe, Benjamin Dudu, Verheyen, Erik, Vree, Frits De & Legera, Jakob Fahr, 2013, Rediscovery of Glauconycteris superba Hayman, 1939 (Chiroptera: Vespertilionidae) after 40 years at Mbiye Island, Democratic Republic of the Congo, European Journal of Taxonomy 42, pp. 1-18 : 6-12

Glauconycteris superba Hayman, 1939

On 19 Feb. 2012, one of ten mistnets was set up in secondary forest on the island, near a clearing where crops were cultivated. During this session (from 18:00 to 06:00) one adult male Glauconycteris superba ( Fig. 2 ) entered the net between 19:00 and 20:00, and was captured alongside a Megaloglossus woermanni Pagenstecher, 1885 , a Rhinolophus landeri Martin, 1838 , and a Casinycteris argynnis Thomas, 1910 . The Glauconycteris specimen was preserved in 90% ethanol and deposited in the collections of the RMCA, where the skull was extracted and cleaned.

Morphological comparison of the four specimens

Figure 3 shows the variation in the white spots among the different specimens. Unfortunately, the specimen from Matonguiné has suffered major damage as it had been dried out for an extended period of time, which resulted in loss of fur and decolouration of the remaining pelage. Still, it is possible to distinguish the white spots on the belly and the head. Drawings of the head made shortly after the time of collection ( Fig. 4 ), illustrate that spots on the head of this specimen were almost identical to those of the other specimens. Among the three remaining specimens, the Mbiye specimen is the darkest, but Hayman (1939, 1947) described his two type specimens as being black, so probably their pelages have faded over the years. Hayman (1947) also indicated that the type specimen of G. s. sheila differed from the type of G. s. superba in having “conspicuous unpigmented areas on the upper surface of the elbow, knee and ankle joints”, suggesting a different colour pattern of G. s. superba . However, as illustrated in Fig. 3 , these unpigmented areas are definitely present on the knees, but not as obvious on the elbows, although the paler colour of the arms might blur this. In the new specimen, these pale areas are present on elbows, knees, and ankles.

The various white spots exhibit some individual variation. The two lateral white bands on the belly are widest in the type of G. s. sheila, followed by the Mbiye specimen, and narrowest in the type of G. s. superba . However, since a major part of the belly was removed from the latter specimen, the width of the bands might be underestimated.

The white spot on the throat varies not as much in its width as in the extension to the sides of the head, where it may or may not become visible on the dorsal side. In Fig. 3 , it appears as if the specimen from Mbiye has a divided throat spot, but this is due to the fact that the throat was cut open to remove the skull.

The three white spots on the head – one median on the nose and two on the crown of the head near the bases of the ears – also show some variation in size, especially the ear spots.

The largest spots on the back are fairly similar in all three specimens. The two spots between the shoulders are widest near the head and tapering to the middle of the back. In the type of G. s. sheila, the distance between the two spots seems to be much wider than in the two other specimens, but this is an artefact due to the position of the shoulder blades, which are fixed close to each other in the latter specimens, thereby concealing the connecting skin in a cavity. From the middle of the back, about the height where the two anterior spots end, two bands run to the lower back where they nearly meet. These two mid-back bands diminish in width from the anterior to the posterior side. In the specimen from Mbiye, the two bands seem to be subdivided in multiple spots, but this is due to the orientation of the individual hairs on the photo, where they are stretched to the sides of the body and not along the length of the body as for the other specimens.

The major difference, however, is in the position, size and number of spots between the mid-back shoulder spots and the neck region. In the two Congolese specimens, only two spots are present on each side, whereas the type of G. s. sheila and the specimen from Matonguiné have three. These extra spots were already reported by Hayman (1947). Hayman links the anterior-most spots with the white belly bands, which end just in front of the spots (see also Cansdale’s photo in Nowak 1999). In the type of G. s. superba , the anterior spots seems to run into belly bands, but in the Mbiye specimen, these ventral bands do not reach as far anteriorly. Here the throat spot reaches slightly further towards the anterior spot of the back. So the anterior-most spots on the back might possibly form a connection with either the belly or the throat spots on the ventral side.

For the specimen from Mbiye, Fig. 3 also shows on the anterior side of the mid-back bands a slight separation between the main part of these bands and its anterior-most part (again depending on how the individual hairs are combed). If more dark hairs were present, this could lead to a split off of the anteriormost part of the mid-back bands. This split-off spot would then be almost similar to the posterior-most small spot found in the type of G. s. sheila, although in the latter specimen this spot is slightly more laterally positioned.

The skulls are very similar in size and shape ( Tabs 1-2 , Figs 5-6 ) although the type of G. s. superba is clearly subadult as indicated by the incompletely fused epiphyses of the wing bones. All skulls show a marked angle at the junction between rostrum and braincase as mentioned by Hayman (1939, 1947). Hayman (1947) also noted that the posterior upper molar (M 3) is considerably reduced. This is indeed the case for all four of the skulls, and most pronounced in the specimen from Matonguiné. All skulls have weak sagittal and lambdoidal crests, which are least developed in the type of G. s. superba and most developed in the type of G. s. sheila. The lack of crest development in the type of G. s. superba is probably age-related. Another character mentioned by Hayman (1939) is the presence of the minute accessory cusplet near the cingulum of the inner upper incisor (I 1). The development of this cusplet is variable, being most pronounced in the type of G. s. sheila and least in the specimen from Mbiye. The position of the outer upper incisor (I 2), described by Hayman (1939) as being “closely crowded between I 1 and the canine”, is indeed very crowded in both type specimens, but this is less the case in the two other specimens. The lower incisors are closely crowded as mentioned by Hayman (1939), and have three cusps. The inner incisors are more or less rectangular in shape, whereas i 2 and i 3 are more triangular.

Morphometric comparison of the four specimens

When based on the collector’s measurements, the specimen from Mbiye Island has a considerably shorter forearm (FA) and Tibia compared to published values ( Tab. 1 ). The comparatively small forearm initially challenged our identification of the Mbiye specimen as G. superba since the FA is given variably in the literature as 47 mm ( Hayman & Hill 1971), greater than 44.0 mm ( Peterson & Smith 1973), and 45 mm ( Rambaldini 2010). However, these differences might be partially explained by individual measurement techniques. Therefore the three specimens currently available at the RMCA were measured again ( Tabs 2-3 ).

The skull measurements of the three specimens in the RMCA are very similar ( Tab. 2 ). Externally, the dimensions of the new specimen fit very well with those of the specimen from Matonguiné, with the exception of Tail length, but this is primarily due to the fact that the tail could not be completely stretched. The tail length appears to be very similar to that of the type from Pawa, but in the latter specimen the point of origin of the tail could not be determined as the abdominal region (including the genital area) had been completely removed during preparation. Considering that the type is subadult, it is remarkable that its long bones (FA and metacarpals) are much larger than the corresponding bones in the two other specimens, and – to a lesser extent – this also is the case for its tibia length ( Tab. 3). Based on the skull measurements, however, this specimen had probably nearly reached its adult size.

In 1972, FDV examined the three specimens available at that time. He noticed that the genital area of the subadult type specimen from Pawa was damaged and that it could not be identified as “probably a male” as mentioned by Hayman (1939). However, his examination also revealed that the nipples were much

better developed than those of the male specimen from Matonguiné and that, therefore, the holotype might represent a female rather than a male.

The forearm length of the type of G. superba agrees very well with that of the type of G. s. sheila (which is a female) and is larger than the specimens from Mbiye and Matonguiné (which are males; Tab. 1 ). This lends support to the suggestion that both types are indeed females. However, the limited number of available specimens does not allow a quantification of the intraspecific variation or sexual dimorphism, hence we are reluctant in assigning a sex to the type specimen of G. superba . If the type specimen is indeed a female, then this suggests that sexual dimorphism might also be present in G. superba , the

* The tail length of the specimen from Pawa is an approximation as the genital area was removed during preparation of the specimen. The tail of the specimen from Mbiye could not be stretched completely. Both tibiae of the specimen from Matonguiné were damaged.

females being larger than the males, as was reported by Koopman (1971) for other species of the genus Glauconycteris .

Figures

Fig. 2. Pelage pattern of the freshly collected Glauconycteris superba Hayman, 1939 specimen from Mbiye Island (RMCA a1.097-M-3153). Upper left: dorsal view, upper right: ventral view, lower left: anterior-dorsal view, lower right: detail of head and breast.

Fig. 3. Pelage pattern of the four known specimens of Glauconycteris superba Hayman, 1939 (upper row: dorsal, lower row: ventral). From left to right: holotype of G. s. sheila Hayman, 1947 (BMNH 47.10), holotype of G. superba (RMCA 14765), new specimen from Mbiye Island (RMCA a1.097-M-3153), and the specimen from Matonguiné (RMCA 97.077-M-7719). Scale bar = 2 cm.

Fig. 4. Head of Glauconycteris superba Hayman, 1939 from Matonguiné (RMCA 97.077-M-7719).

Fig. 5. Crania of the four known specimens of Glauconycteris superba Hayman, 1939 (left row: dorsal, middle row: ventral; right row: lateral). From top to bottom: specimen from Matonguiné (RMCA 97.077- M-7719, ♂), Mbiye Island (RMCA a1.097-M-3153, ♂), holotype of G. superba (RMCA 14765,?), and holotype of G. s. sheila Hayman, 1947 (BMNH 47.10, ♀). Scale bar = 1 cm

Fig. 6. Mandibles of the four known specimens of Glauconycteris superba Hayman, 1939 (upper row: dorsal view, lower row: lateral view). From left to right: holotype of G. s. sheila Hayman, 1947 (BMNH 47.10, ♀) [lateral picture flipped to fit the orientation of the other pictures], holotype of G. superba (RMCA 14765,?), new specimen from Mbiye Island (RMCA a1.097-M-3153, ♂), and the specimen from Matonguiné (RMCA 97.077-M-7719, ♂). Scale bar = 1 cm.