| Isalo serotine | |
|---|---|
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Chiroptera |
| Family: | Vespertilionidae |
| Genus: | Laephotis |
| Species: | L. malagasyensis |
| Binomial name | |
| Laephotis malagasyensis (Peterson, Eger, and Mitchell, 1995) | |
 | |
| Collection localities ofLaephotis malagasyensis | |
| Synonyms | |
TheIsalo serotine (Laephotis malagasyensis) is avesper bat ofMadagascar in the genusLaephotis. It is known only from the vicinity of theIsalo National Park in the southwestern part of the island, where it has been caught in riverine habitats. After the first specimen was caught in 1967, it was described as asubspecies ofEptesicus somalicus (nowNeoromicia somalica) in 1995. After four more specimens were collected in 2002 and 2003, it was recognized as a separate species. Because of its small distribution and the threat ofhabitat destruction, it is considered "vulnerable" in theIUCN Red List.
Laephotis malagasyensis is a relatively small species, with a forearm length of 30 to 32 mm (1.2 to 1.3 in) and a body mass of 3.9 to 9 g (0.1 to 0.3 oz). The fur is dark brown above and mixed buff and gray below. The ears are translucent and thetibia is short. Thebaculum (penis bone) resembles that ofN. melckorum, but is smaller.[4] The duration of theecholocation call, which consists of a component with rapidly falling frequency and one showing more stable frequency, averages 4.9 ms and the interval between calls averages 69.1 ms.
In their 1995 review of Malagasy bats, Randolph Peterson and colleagues establishedEptesicus somalicus malagasyensis, a newsubspecies ofEptesicus somalicus[2] (currentlyNeoromicia somalica).[Note 1] They had only a single specimen and noted that further material was needed to assess the new form's relationship withE. somalicus.[6] Studies in 2001 and 2002 provided evidence thatE. somalicus and related species are not closely related toEptesicus (nor toPipistrellus, where they have also been placed), so that these species were allocated to the separate genusNeoromicia.[7] In 2004,Steven Goodman and Julie Ranivo reviewed the Malagasy subspecies after collecting two more specimens[8] and concluded that it was distinct enough to be classified as a separate species,Neoromicia malagasyensis.[3] Two years later, Paul Bates and colleagues reported on two more specimens[9] and showed that thebacula (penis bones) ofN. malagasyensis andN. somalica are different, providing further evidence that they are distinct species. However, they recommended that further research assess the degree of difference betweenN. malagasyensis andN. matroka (formerly inEptesicus, but placed inNeoromicia by Bates and colleagues, and later placed inLaephotis), which occurs further east in Madagascar.[10] TheIUCN Red List currently again classifies the species inEptesicus, asEptesicus malagasyensis.[1] In 2020, a phylogenetic analysis found it to belong toLaephotis as opposed toNeoromicia, and classified it as such.[11][12]
Laephotis malagasyensis is one of at least six species of smallvespertilionid bats ("pipistrelles") on Madagascar, in addition toL. matroka,L. robertsi,Pipistrellus hesperidus,P. raceyi, andNycticeinops anchietae. The classification of these bats has historically been controversial, leading to many changing identifications and generic assignments.[13] The genusLaephotis is exclusively African and included 4 species in the 2005 third edition ofMammal Species of the World;[14] more species, likeL. malagasyensis andL. matroka, have been added since.Common names proposed for this species include "Isalo Serotine"[1] and "Peterson's 'pipistrelle'".[10]
| Specimen | Sex | Forearm | Tail | Hindfoot | Ear | Mass |
|---|---|---|---|---|---|---|
| ROM 42713[Note 2][15] | Female | 32 | 27 | 6[Note 3] | 12 | 9 |
| FMNH 175988[15] | Male | 30 | 37 | 4[Note 4] | 11 | 3.9 |
| FMNH 175989[15] | Female | 32 | 35 | 5[Note 4] | 12 | 6.0 |
| UA, uncatalogued[16] | Male | 30.1 | 30.4 | 5.3[Note 4] | 9.8 | – |
| UA, uncatalogued[16] | Female | 32.0 | 29.3 | 6.9[Note 4] | 11.4 | – |
| All measurements are in millimeters, except mass in grams. | ||||||
Laephotis malagasyensis is a relatively small "pipistrelle",[9] but larger thanNeoromicia somalica.[17] The fur on the back is long and dark brown and the underparts contain both gray and darkbuff hairs; there, the fur becomes lighter towards the tail.[10] The fur is darker than inN. somalica,[6] but paler than inL. matroka.[18] The brown ears are translucent.[10] Thetragus (a projection on the inner side of the outer ear) is similar to that ofN. somalica, but may be a little narrower.[17] Relative to the two other MalagasyLaephotis species, thetibia is short. A singlebaculum (penis bone), 2.2 mm long, has been studied. It resembles the baculum ofL. robertsi, but is smaller. As inL. matroka, the distal (far) end is flat and displaced downwards, but theL. malagasyensis baculum has a smaller area and less well-developed flanges at the sides and a smaller vertical extension of the bone.[10]
The skull is somewhat smaller than that ofL. matroka[10] and thebraincase andpalate are narrower.[18] Compared toN. somalica, the skull is broader.[6] The ridge on thelacrimal bone is better developed, the palate is broader, thefrontal bones contain a depression and are swollen at the sides, themastoid bones are smaller,[17] and thecoronoid andangular processes of themandible (lower jaw) are more prominent.[3]
Theecholocation call of this species was reported in a 2007 study that consists of a component with rapidly falling frequency followed by one with more slowly changing frequency.[19] The call takes 3.6 to 6.3 ms, averaging 4.9 ms, and the period between two calls is 34.2 to 94.4 ms, averaging 69.1 ms. The maximum frequency averages 79.8 kHz, the minimum frequency averages 40.5 kHz, and the call emits the most energy at a frequency of 45.7 kHz.[20]
Laephotis malagasyensis is known only from the vicinity ofIsalo National Park, an area of about 2000 km2 (800 sq mi), in interior southwestern Madagascar.[1] Theholotype was caught in 1967 in amistnet set in a row of palms along a river in dry savannah habitat.[21] Peterson and colleagues reported that it had been collected near the village ofMarinday,[2] but Goodman and Ranivo suggested that it may instead have come from nearIlakaka.[8] Two specimens, a male and a female, were collected at different localities in Isalo National Park in early December 2002, both in mistnets near rivers. The male had enlargedtestes and the female had recently stoppedlactating and had largemammae.[8] Two others followed in 2003, also from the national park, and caught in woodland near rivers.[22] A 2009 study on echolocation described the call of six individuals ofL. malagasyensis from an unspecified site within the national park.[23] In view of its small known range and the threat ofhabitat destruction, theIUCN Red List assesses the species as "vulnerable"; further research is recommended on its roosting and dietary habits.[1]
