Nyctimene certans Andersen, 1912b

Irwin, Nancy, 2017, A new Tube-nosed Fruit Bat from New Guinea, Nyctimene wrightae sp. nov., A Re-diagnosis of N. certans and N. cyclotis (Pteropodidae: Chiroptera), and a Review of their Conservation Status, Records of the Australian Museum 69 (2), pp. 73-100 : 81-84

publication ID	https://doi.org/ 10.3853/j.2201-4349.69.2017.1654
persistent identifier	https://treatment.plazi.org/id/706DD361-D44B-FFE9-FF29-A91798F9CBE6
treatment provided by	Felipe
scientific name	Nyctimene certans Andersen, 1912b
status

Treatment

Nyctimene certans Andersen, 1912b View in CoL

Figs 2–5 View Figure 2 View Figure 3 View Figure 4 View Figure 5 , 7–12 View Figure 7 View Figure 8

Type locality. Mount Goliath, Prov. of Papua, Indonesia.

Holotype. NHMUK 1911.11 View Materials .29.1. ♂ adult, skin and skull.

Common name. Mountain tube-nosed fruit bat.

Distribution. Upper montane forest of New Guinea, above 700 m up to 3000 m asl but typically most localities lie between 1600–2500 m.

Specimens examined. 39 including the holotype, see Appendix 1.

Revised diagnosis. Nyctimene certans differs from all other Nyctimene species in having the shortest upper (<32%) and lower (<36%) tooth rows relative to skull length ( Table 2, Figs 2 View Figure 2 , 4 View Figure 4 ). Nyctimene certans further differs from N. cyclotis in having a relatively broader palate, with a P 3 -P 3 markedly longer than the upper post-canine tooth row (P 1 -M 1), vs. slightly longer than P 1 -M 1 in N. cyclotis ; N. certans also has a longer second digit, especially the 2M- 2P. On average it is larger and darker dorsally than any other medium-sized Nyctimene species from mainland New Guinea. It also has the broadest cheek-teeth relative to skull size (esp. P 3), which are almost as broad as they are long, compared to any other species of Nyctimeninae .

Description. Essentially Andersen’s original description stands ( Andersen, 1912b), validated by a larger series than the two specimens available to Andersen. Nyctimene certans is a medium-sized species for the subfamily with a forearm range of 54.8–67.4 mm.

The fur colour is dark grey and grizzled with wood-brown on the back; it has for the subfamily, the largest proportion of the base of the hair shaft being dark brown (30–40%) and likewise the tips of the hairs dark brown (10–30% of the hair shaft) ( Figs. 5 View Figure 5 , 7 View Figure 7 ).

Nyctimene certans has a significantly longer skull, with CBL, C 1 -M 2, Zygo-L larger than the other sympatric medium-sized species ( Tables 1 and 2). Its brain case is longer but not as broad as the similar N. wrightae sp. nov. ( Fig. 4 View Figure 4 ). Further specimens may also show this to be the case for N. cyclotis .

The skull of the holotype specimen is badly broken as noted previously ( Peterson, 1991; Andersen, 1912b). Only the anterior half of the skull remains, consisting of the palate, rostrum and half of the left zygomatic arch ( Fig. 2 View Figure 2 ), from which the characteristic rounded dental arcade, and large, broad, cuspidate teeth are apparent. The lower mandible is in better condition with only the right angular process broken off and missing ( Fig. 2 View Figure 2 ).

Peterson (1991) discussed the possibility that the holotype of N. certans is a sub-adult due to the metacarpal lengths being relatively short, together with the highly cuspidate teeth. Indeed the type specimen has one of the shortest FA and metacarpals of the specimens assigned to N. certans here and the 5M-1P and 5M-2P are particularly short. The teeth are large and compacted; additionally the cusps are well defined similar to a sub-adult. However the teeth do show wear, as indicated by exposed dentine on the molars, suggestive of some use, more than that anticipated in a juvenile. Therefore overall, although the individual is clearly not very old, I concur with Andersen (1912b) who considered the specimen to be an adult.

The wings of N. certans are deeper than its sympatric congeneric species; primarily caused by a significantly longer 5th digit, especially the 1st phalanx ( Tables 2, 3). The wings also, on average, have significantly longer 2M-2P than their sympatric congenerics ( Tables 2, 3). Bats with a 2M-2P above 8.0 mm and a ratio 5-MET / 5M-1P below 2.0 are therefore likely to be N. certans ( Fig. 3 View Figure 3 ). A combination of these three external wing measurements therefore typically separates N. certans from the other sympatric Nyctimene of similar body-size including the externally very similar N. cyclotis ( Fig. 3 View Figure 3 ).

Remarks. Smith & Hood (1983) based their concept of N. cyclotis from specimen BPBM 28398 (photographed in fig. 1c of their paper) but I concur with Peterson (1991) who identified this specimen as N. certans .

Nyctimene certans is the only species within the subfamily to have round palatal fenestrations (vacuities) at the distal end of the palate. However, as noted by Smith & Hood (1983), this character is variable, sometimes with two present as in BPBM 28398 (Smith & Hood, 1983) and AM M.7908 (as illustrated in Flannery, 1995b), or none as for AM M.17888 ( Fig. 4 View Figure 4 ). The only other recorded case of a palatal fenestration in another species of the subfamily is an AMNH specimen of N. major from Kiriwina Island. Koopman (1982) discussed this specimen and concluded that it was very aged and somewhat pathological, adding that there was secondary bone deposition lateral to the molars. It is unlikely that these fenestrations have any function, as they are so variable between individuals. They could therefore represent a vestigial pattern of growth or possibly an indication of masticator stress on the palate, arising from eating hard fruit during growth as is thought to occur in other mammals (Moss & Feliciano, 1977). They remain a feature generally found only in N. certans .

The yellow colour of the ear and wing spots fades on fixation in alcohol in N. certans ( Flannery, 1995b) , similar to N. cyclotis , and therefore colour assessment from specimens preserved in alcohol may not be entirely accurate.

Little is known of the biology of N. certans , including its diet, population density, home range, or life expectancy. What natural history is reported is usually from short-term expeditions of less than a few weeks and is summarized in the excellent mammal and field guides of the region ( Flannery, 1995b; Bonaccorso, 1998).