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Miniopterus aelleni

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Miniopterus aelleni
Scientific classification
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M. aelleni
Binomial name
Miniopterus aelleni
Goodman et al., 2009

Miniopterus aelleni is a bat in the genus Miniopterus that occurs on Anjouan in the Comoros and in northern and western Madagascar. Populations of this species have historically been included in Miniopterus manavi, but molecular data published in 2008 and 2009 indicate that this supposed species in fact consists of five separate species, including the newly described M. aelleni. Up to four species of this complex may occur in the same place. M. aelleni has been found in forests and caves in karstic areas. Its distribution generally overlaps that of M. griveaudi, also formerly included in M. manavi.

Miniopterus aelleni is a small, brown Miniopterus; its forearm length is 35 to 41 mm (1.4 to 1.6 in). The long tragus (a projection in the outer ear) has a broad base and a blunt to rounded tip. The uropatagium (tail membrane) is sparsely haired. The palate is flat and there are distinct diastemata (gaps) between the upper canines and premolars.

Taxonomy

During the 2000s, molecular studies have revealed that the widely distributed Old World genus Miniopterus is much more diverse and species-rich than previously thought. In a 1995 contribution to Faune de Madagascar on Malagasy bats, Randolph Peterson and colleagues listed four species of Miniopterus on Madagascar and the nearby Comoros, including the small Miniopterus manavi with a broad distribution on both Madagascar and the Comoros.[1] In 2008, a study comparing sequences of the mitochondrial cytochrome b and D-loop markers found two different, unrelated groups within Comoro "M. manavi"; both groups were also found on Madagascar.[2] The next year, Steven Goodman and colleagues revisited the group with more extensive sampling on Madagascar. They separated three species within the former "M. manavi": M. manavi itself in the Central Highlands, M. griveaudi (previously a subspecies of M. manavi) on Anjouan and Grande Comore in the Comoros and northern and western Madagascar, and the newly described Miniopterus aelleni on Anjouan and northern and western Madagascar.[3] The specific name aelleni honors Prof. Villy Aellen of the Natural History Museum of Geneva, who has done much work on African bats.[4] Within M. aelleni, Goodman and colleagues found some differentiation (3.4% divergence in cytochrome b sequences) between on the one hand individuals from Montagne d'Ambre in northern Madagascar and on the other hand those from Anjouan and Ankarana, near Montagne d'Ambre; the cytochrome b difference between M. aelleni and other Malagasy Miniopterus is 7 to 10%.[5]

Later in 2009, Goodman and colleagues described two more species of M. manavi-like Malagasy Miniopterus: M. brachytragos from northern Madagascar and M. mahafaliensis from the southwest.[6] On the basis of cytochrome b sequences, they found that M. aelleni was most closely related to a clade of M. brachytragos, M. manavi, and another recently described Malagasy species, M. petersoni.[7] The five recognized species of M. manavi-like bats are not each others' closest relatives, but apparently acquired their similarities through convergent evolution.[8] At some places (for example, Namoroka) four cryptic species of M. manavi-like bats, including M. aelleni, may occur together.[9]

Description

Measurements[10]
Island n Total length Tail Hindfoot Tragus Ear Forearm Mass
Anjouan 5 89.8 (88–91) 43.4 (41–46) 5.2 (5–6) 6.0 (6–6) 10.6 (10–11) 38.2 (37–39) 5.6 (4.7–6.5)
Madagascar 12 90.7 (88–95) 42.1 (40–45) 6.1 (5–7) 6.1 (5–8) 11.1 (10–12) 38.8 (35–41) 4.6 (3.9–6.5)
All measurements are in the form "mean (minimum–maximum)" and are in millimeters, except mass in grams.

Miniopterus aelleni is a small, brown Miniopterus species. The head may be slightly lighter than the body. Some hairs on the underparts have buff tips.[11] Miniopterus griveaudi is similar in color, but M. manavi is darker[12] and M. brachytragos and M. mahafaliensis are lighter.[13] The tragus (a projection on the inner side of the outer ear) is long and has a broad base with a crest at the side, and ends in a blunt to slightly rounded tip.[14] In M. manavi and M. griveaudi, the base is narrower,[12] in M. mahafaliensis, the sides of the tragus are parallel, and M. brachytragus has a short, blunt tragus sparsely covered with hair.[15] The wing membrane is also brown, but the uropatagium is lighter. The wing membrane and uropatagium are attached to the upper leg at the same level, above the ankle. The uropatagium is sparsely covered with thin, but clearly visible hairs.[14] In contrast, M. manavi, M. mahafaliensis, and M. brachytragos have a densely covered uropatagium and that of M. griveaudi is almost naked.[16] Animals from Anjouan have significantly shorter hindfeet than those from Madagascar, but otherwise the two populations cannot be distinguished on the basis of external characters.[14]

In the skull, the rostrum (front part) is short and line-shaped,[14] but longer than in other manavi-like species.[16] The central groove in the nasal depression is relatively narrow. The frontal bones are rounded and bear a well-developed sagittal crest. Further back on the braincase, the lambdoid crest is also prominent.[14] The middle part of the palate is flat, as in M. manavi but unlike in M. brachytragos, M. griveaudi, and M. mahafaliensis, which have a curved palate.[16] At the palate's back margin is a long, thin posterior palatal spine. Miniopterus aelleni has 36 teeth in the dental formula 2.1.2.33.1.3.3 (two incisors, one canine, two premolars, and three molars in both upper toothrows and three incisors, one canine, three premolars, and three molars in the lower toothrows). As is characteristic of Miniopterus, the first upper premolar (P2—P1 and P3 are missing) is smaller and more simplified than the second (P4).[14] There are clear diastemata (gaps) between the upper canine (C1) and P2 and between P2 and P4, which are weaker or absent in M. griveaudi and M. manavi. Behind C1, the toothrows are about parallel, not divergent as in M. manavi. The third upper molar (M3) is more compressed than in M. manavi and M. griveaudi.[12] In some measurements of the skull and teeth, Anjouan animals are larger than their conspecifics from Madagascar.[14]

Distribution and ecology

Miniopterus aelleni is known from 4 to 225 m (10 to 740 ft) above sea level in northern and western Madagascar, at 1100 m (3610 ft) on Montagne d'Ambre, northern Madagascar, and at 220 to 690 m (720 to 2260 ft) on Anjouan in the nearby Comoros.[4] On Madagascar, it has been recorded in forest and caves in karst areas; its distribution broadly overlaps that of M. griveaudi and the two have been found in the same roost sites on several occasions.[17] On Anjouan, M. aelleni is less common than M. griveaudi; there, it is known from four specimens only, all collected in 2006. These come from two nearby sites: a rocky area near a river and a disturbed forest.[18] These animals, collected in late November, were in reproductive condition, with two females pregnant and a third lactating. M. griveaudi were reproductively active at the same time, suggesting that the reproductive seasons of the two do not differ significantly.[19] Because M. aelleni is widespread and occurs in many protected areas on Madagascar, Goodman and colleagues inferred that its conservation status is secure.[20]

References

  1. ^ Goodman et al., 2009a, p. 340
  2. ^ Weyeneth et al., 2005, p. 5205
  3. ^ Goodman et al., 2009a, p. 339
  4. ^ a b Goodman et al., 2009a, p. 353
  5. ^ Goodman et al., 2009a, p. 355
  6. ^ Goodman et al., 2009b, p. 1
  7. ^ Goodman et al., 2009b, p. 6, fig. 2
  8. ^ Goodman et al., 2009b, p. 28
  9. ^ Goodman et al., 2009b, p. 30, table 7
  10. ^ Goodman et al., 2009a, table 2
  11. ^ Goodman et al., 2009a, pp. 353–354
  12. ^ a b c Goodman et al., 2009a, p. 356
  13. ^ Goodman et al., 2009b, pp. 21–22
  14. ^ a b c d e f g Goodman et al., 2009a, p. 354
  15. ^ Goodman et al., 2009b, p. 21
  16. ^ a b c Goodman et al., 2009b, p. 22
  17. ^ Goodman et al., 2009a, pp. 358–359
  18. ^ Goodman et al., 2010, p. 131
  19. ^ Goodman et al., 2010, pp. 131–132
  20. ^ Goodman et al., 2009a, p. 359

Literature cited