Triaenops menamena

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Triaenops menamena
Skull of Triaenops menamena

Least Concern  (IUCN 3.1) (as Triaenops rufus)[1]
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Chiroptera
Family: Rhinonycteridae
Genus: Triaenops
Species:
T. menamena
Binomial name
Triaenops menamena
Goodman and Ranivo, 2009
Triaenops has a fragmented distribution in Africa, the Middle East, and southern Pakistan.
Distribution of Triaenops menamena (in green) and other species of Triaenops
Triaenops menamena range

Triaenops menamena is a

habitat degradation
, it is not considered to be threatened.

With a forearm length of 50 to 56 mm (2.0 to 2.2 in) in males and 46 to 53 mm (1.8 to 2.1 in) in females, this is a medium-sized bat. Its fur color is variable, ranging from reddish brown to gray, but it is generally darker than the species in the closely related genus Paratriaenops which also occur on Madagascar. The skull contains a pronounced swelling around the nose and the second upper premolar is displaced outside the toothrow. The maximum frequency of the echolocation call averages 94.2 kHz and the species can easily be recognized on the basis of its call.

Taxonomy

In 1881,

Triaenops persicus, a possibility Hill had discussed,[3] but most authors regarded the two as distinct species.[4] In 2006, Julie Ranivo and Steven Goodman revised Madagascan Triaenops and found little variation among specimens of T. rufus from throughout the dry parts of the island.[5] Three years later, they published another paper which showed that the original material of T. rufus and T. humbloti was distinct from Madagascan specimens identified as "Triaenops rufus" and more similar to T. persicus.[6] On his journey to Madagascar, Humblot had stayed in Somalia and Yemen, and Goodman and Ranivo concluded that he had probably collected the Triaenops there, after which their provenance was incorrectly recorded.[7] Thus, rufus and humbloti cannot be used for the Madagascan species, and Goodman and Ranivo proposed the new name Triaenops menamena for the species formerly known as T. rufus. The specific name menamena is Malagasy for "reddish", referring to the animal's coloration.[8] "Rufous trident bat" has been used as a common name for Triaenops rufus.[1]

Triaenops menamena is currently one of four living species in the genus Triaenops; a 2009 revision by Petr Benda and Peter Vallo split off the African

phylogenetic and coalescent methodologies to investigate the history of the Triaenops group. They found that T. menamena (as T. rufus) was closest to mainland African Triaenops (but did not study Middle Eastern bats) and concluded that T. menamena and the species of Paratriaenops (then still placed in Triaenops) independently reached Madagascar from Africa; the colonization of the island by T. menamena was dated to about 660,000 years ago.[11] Benda and Vallo also studied phylogenetic relationships in Triaenops and included Middle Eastern T. persicus and T. parvus in their analysis. They found little resolution of relationships within Triaenops, but some evidence suggested that T. menamena is more closely related to the Middle Eastern species than to T. afer in mainland Africa; therefore, T. menamena may have reached Madagascar from the Middle East or northeastern Africa. They also placed the split between T. menamena and the other species much further back, at around 4 million years ago.[12]

Description

Measurements[13]
Sex n[Note 1] Total length Tail Hindfoot Ear Forearm Mass
Male 28[Note 2] 90–104 27–38 6–9 14–17 50–56 8.2–15.5
Female 67 86–98 28–39 6–9 12–17 46–53 6.6–11.5
Measurements are in millimeters (except weight in grams) and in the form "minimum–maximum".

Triaenops menamena is a medium-sized species with variable fur coloration, ranging from reddish brown to gray. It is larger and darker than Paratriaenops auritus and P. furcula.

uropatagium (tail membrane).[18] Males average slightly larger than females.[13] Wingspan is 270 to 305 mm (10.6 to 12.0 in).[19]

The skull is similar to that of Madagascan Paratriaenops, but the

angular process (both processes at the back of the bone) is small.[23]

The upper

hypoconid; these cusps are about as high in T. goodmani.[10]

The species can easily be identified from recordings of its echolocation call.[24] The call consists of a component with constant frequency followed by a short one with changing frequency. The call takes 6.5 to 13.5 ms, averaging 10.1 ms, and the period between two calls is 22.7 to 86.3 ms, averaging 42.7 ms. The maximum frequency averages 94.2 kHz, the minimum frequency averages 82.0 kHz, and the call emits the most energy at a frequency of 93.2 kHz.[25]

Distribution and ecology

Triaenops menamena mainly occurs in the dry regions of western Madagascar, but has also been recorded in humid areas in the far southeast and northeast,

Coleoptera (beetles) and Hemiptera (bugs) and fewer members of some other insect orders.[30] It is unclear how the ecological niches of Triaenops and the less frequently captured Paratriaenops furcula are separated, as both eat lepidopterans and occur in the same regions.[31]

Conservation status

Under Triaenops rufus, the

Hipposideros commersoni, are sometimes hunted for food in southwestern Madagascar, and T. menamena is also taken incidentally.[32]

Footnotes

  1. ^ Number of specimens measured.
  2. ^ 27 for total length.

References

  1. ^ a b c d e Andriafidison et al., 2008
  2. ^ Milne-Edwards, 1881, p. 1035
  3. ^ Goodman and Ranivo, 2009, p. 47; Benda and Vallo, 2009, table 1
  4. ^ Benda and Vallo, 2009, p. 7
  5. ^ Ranivo and Goodman, 2007, pp. 963, 975
  6. ^ Goodman and Ranivo, 2009, p. 52
  7. ^ Goodman and Ranivo, 2009, pp. 52–53
  8. ^ a b Goodman and Ranivo, 2009, p. 54
  9. ^ Benda and Vallo, 2009, p. 34
  10. ^ a b c Samonds, 2007, p. 46
  11. ^ Russell et al., 2007, p. 839; 2008, p. 995
  12. ^ Benda and Vallo, 2009, pp. 27–28
  13. ^ a b Ranivo and Goodman, 2006, p. 982
  14. ^ a b c Peterson et al., 1995, p. 82
  15. ^ a b Benda and Vallo, 2010, p. 29
  16. ^ a b Yoshiyuki, 1995, p. 119
  17. ^ Goodman and Ranivo, 2008, p. 686
  18. ^ a b Yoshiyuki, 1995, p. 120
  19. ^ Garbutt, 2007, p. 71
  20. ^ a b Ranivo and Goodman, 2006, p. 971
  21. ^ a b Ranivo and Goodman, 2006, p. 972
  22. ^ Benda and Vallo, 2010, pp. 29–30
  23. ^ a b c Ranivo and Goodman, 2006, p. 974
  24. ^ Kofoky et al., 2007, p. 1042
  25. ^ Kofoky et al., 2009, table 1, p. 380, fig. 4a
  26. ^ Kofoky et al., 2007, p. 1049
  27. ^ Racey et al., 2010, p. 392
  28. ^ Olsson et al., 2006, p. 402; Kofoky et al., 2007, p. 1047
  29. ^ Russell et al., 2008, p. 998
  30. ^ Rakotoarivelo et al., 2007, table 2
  31. ^ Rakotoarivelo et al., 2007, p. 964
  32. ^ Goodman, 2006, pp. 225–226

Literature cited

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