Systematics of Megachiropteran Bats in the Solomon Islands Part 9

_Specimens examined_ (three males and one female; in alcohol).--Choiseul, in April, 23413-14, 23434, 23275.

_Measurements._--Average and extreme measurements of three males and one female are as follows: Length of head and body, 86.1 (83.1-91.0); hind foot, 19.6 (17.2-22.2); ear, 11.3 (10.8-11.7); length of forearm, 54.4 (52.1-57.7).

_Remarks._--Specimens of _Melonycteris woodfordi_ from Choiseul const.i.tute a new locality of occurrence for the species. Apparently _M.

woodfordi_ occurs throughout the Solomons (see Fig. 11).

Thomas (1887_a_:147) named _Nesonycteris woodfordi_ in a preliminary report that appeared before the publication of the more detailed description of the genus and species (1887_b_:323-324). In the second paper he stated that the anterior projections of the premaxillary bones are separated distinctly in both _Nesonycteris_ and _Melonycteris_.

According to Thomas (1887_b_:323), it was by some "accident" that Dobson (1878:4) reported the anterior projections of the premaxillary bones in _Melonycteris melanops_ to be united. Writing at a later date, Andersen (1912:785) reported that in _Melonycteris melanops_ the premaxillary bones have "simple contact with each other." Furthermore, in Andersen's (1912:791) ill.u.s.tration of _M. woodfordi_ the premaxillary bones are in contact anteriorly. In specimens of _woodfordi_ and _melanops_ examined by me, the premaxillary bones are in contact. In _M. aurantius_ the premaxillary bones are not in contact, and it differs from _woodfordi_ in several other respects.

In _M. woodfordi_, as in other macroglossine bats, there is variability in dent.i.tion. One specimen examined has a total of three upper incisors, and another had an extra peglike tooth just anterior to I1.

Subfamily Nyctimeninae

=Nyctimene= Borkhausen

1797. _Nyctimene_ Borkhausen, Deutsche fauna ..., 1:86.

1810. _Cephalotes_ e. Geoffroy, Ann. du Mus. d'Hist. Nat., 15:104.

1811. _Harpyia_ Illiger, Prodr. Syst. Mamm. et Avium, p. 118.

1837. _Gelasinus_ Temminck, Monographe de Mammalia ..., 2:100.

Tube-nosed bats of the genus _Nyctimene_ occur from Celebes on the west to the Santa Cruz Islands on the east. Heretofore, two species (_N.

albiventer_ and _N. major_), each with an endemic subspecies, were known from the Solomon Islands. Both species occur also in New Guinea and on many adjacent islands. A new species of _Nyctimene_, apparently endemic to the Solomons, and a new subspecies of _N. albiventer_ are named beyond.

_Nyctimene_ is related closely to _Cynopterus_ and the "Cynopterus group" of Andersen (1912:691). Because _Nyctimene_ is a highly specialized bat, Miller (1907:75) placed it in a subfamily separate from that of _Cynopterus_ and its allies.

Andersen (1912:696, 697) placed the species of _Nyctimene_ previously known from the Solomons in two groups, the "papua.n.u.s" group and the "cephalotes" group, on the basis of difference in length of forearm and length of maxillary tooth-row. Because of its short forearm (about 58), _N. albiventer_ is in the _papua.n.u.s_ group; and _N. major_, because of its long forearm (about 74), is in the _cephalotes_ group.

Key to Species of Nyctimene in the Solomons

1. Forearm longer than 70; males grayish-brown, females pale gray, =N. major scitulus=, p. 825

1'. Forearm shorter than 70; males dark brown, females pale brown, 2

2(1'). Forearm about 65, =N. malaitensis=, p. 822

2'. Forearm less than 61, =N. albiventer=, p. 818

=Nyctimene albiventer=

This species occurs throughout New Guinea and on many adjacent islands, including the Bismarck Archipelago and the Admiralty and Solomon islands. The species varies geographically and five subspecies are recognized. The two subspecies in the Solomons resemble _N. albiventer papua.n.u.s_, the subspecies that ranges from eastern New Guinea to New Britain. _N. albiventer bougainville_ occurs in the western chain of islands of the Solomons, whereas another subspecies, named as new beyond, occurs in the eastern chain of islands (see Fig. 12).

s.e.xual dichromatism is striking. As Andersen (1912:690) previously reported, females generally are paler, more brownish than males, which are dark and have a better defined black dorsal stripe.

=Nyctimene albiventer bougainville= Troughton

1936. _Nyctimene bougainville_ Troughton, Rec. Australian Mus., 19:349, April 7, type from Bougainville.

1954. _Nyctimene albiventer bougainville_, Laurie and Hill, List of land mammals of New Guinea, Celebes and adjacent islands, p. 46, June 30.

1953. _Nyctimene papua.n.u.s bougainville_, Pohle, Z. Saugetierk., 17:130, October 27.

_Specimens examined_ (nine males, one female; nine in alcohol, nine crania extracted and cleaned).--Bougainville in December, AM-M. 5786 (paratype); Guadalca.n.a.l in May, 23812, 23815, 23827; Kolombangara in January and February, 23369, 23381, 23388, 23406, 23444, 23456.

_Measurements._--See Table 3.

_Remarks._--Heretofore, _Nyctimene albiventer bougainville_ was not known from Kolombangara and Guadalca.n.a.l. The subspecies apparently ranges throughout the western chain of the Solomons.

Troughton (1936:350) considered _Nyctimene bougainville_ specifically distinct from its nearest ally, _N. papua.n.u.s_. Pohle (1953:130) did not examine specimens of either kind, but on the basis of Troughton's description decided that _N. bougainville_ differed only subspecifically from _N. papua.n.u.s_. Laurie and Hill (1954:46) synonymized _bougainville_ and _papua.n.u.s_ with _N. albiventer_. However, Troughton (1936:350) pointed out that in addition to size _bougainville_ differed from _papua.n.u.s_ by having narrower and longer pm3 and pm4. Judging from specimens examined by me, such is the case, and the difference is even more p.r.o.nounced in m1.

Specimens of _N. a. bougainville_ from Kolombangara and Guadalca.n.a.l agree with a paratype of this subspecies from Bougainville. Geographic variation, if present in the population in the western chain of islands (see Fig. 12), is slight and not notable in the series available. Some individual variation was found, especially in the shape of the interorbital region of the skull. An adult male from Kolombangara is unusually dark, almost black; color of the other specimens (all in alcohol) is consistent according to s.e.x.

_Nyctimene albiventer_ from Choiseul and Santa Ysabel is smaller, in all respects, than _N. albiventer_ from Bougainville, Kolombangara, and Guadalca.n.a.l (see Table 3), and therefore may be named and described as follows:

=Nyctimene albiventer minor=, new subspecies

_Type._--Adult male, skin and skull, in good condition (originally stored in alcohol for about one year), no. BSIP 23636, Bernice P. Bishop Museum; from Choiseul Island, British Solomon Islands Protectorate; obtained on 11 March 1964, by Philip Temple, original number 1441.

_Distribution._--Known only from Choiseul and Santa Ysabel islands (see Fig. 12).

_Diagnosis._--Small for _Nyctimene_; wing membranes brown with scattered yellow spots (dried specimens); uropatagium, feet, and ears brown; dorsum of tibia set with hair, ventral surface naked; dorsum of uropatagium spa.r.s.ely set with pale brown hairs, ventral surface almost bare; fringe of hairs along two centimeters of dorsal and ventral surfaces of trailing edge of wing membrane; proximal third of dorsal surface of forearm spa.r.s.ely set with hairs; pelage of back soft and thick, of medium length (about 7); hair on crown and nape short (about 4); well-defined black dorsal stripe, extending from uropatagium to shoulders; skull resembling that of other subspecies of _N. albiventer_ but relatively smaller; zygomatic arch delicate, slender anteriorly; P2 small (see Fig. 14). s.e.xually dichromatic as follows: male--dorsum Hair-Brown, bases of hairs darker; hair on throat spa.r.s.e, medium length (about 6), Hair-Brown; fur along sides of abdomen Drab; female--dorsum having Buffy-Brown cast, some individual hairs Hair-Brown; shoulders Sayal-Brown; hair on throat spa.r.s.e, Hair-Brown on throat and midline of abdomen; sides of abdomen Sayal-Brown.

_Comparisons._--From _Nyctimene major scitulus_, the largest member of this genus in the Solomons, _N. a. minor_ differs in being smaller in all measurements taken; forearm averaging 54.8 as opposed to 73.5; greatest length of skull 28.2 as opposed to 37.0, and females pale brown instead of pale gray.

From nine adults of _Nyctimene albiventer bougainville_ from Bougainville, Kolombangara, and Guadalca.n.a.l, _minor_ differs as follows: averaging slightly smaller in all dimensions; forearm averaging 54.8 as opposed to 57.9; second metacarpal averaging 27.4 as opposed to 28.3; 5th metacarpal averaging 38.5 as opposed to 40.0; condylobasal length 26.7 as opposed to 28.0; length of mandibular tooth-row 10.3 as opposed to 10.9; mandible smaller (see Fig. 14); dorsal stripe fainter.

From _Nyctimene albiventer papua.n.u.s_, known from eastern New Guinea, New Britain, and the Admiralty Islands, _minor_ differs as follows: slightly smaller in most dimensions; forearm averaging 54.8 as opposed to 57.0; length of maxillary tooth-row 8.9 as opposed to 9.8; length of mandibular tooth-row 10.3 as opposed to 11.0; breadth across upper third premolars notably less (7.5 as opposed to 8.4).

_N. a. minor_ differs from _N. albiventer albiventer_ Gray, which occurs about 800 miles to the west of _minor_, in ways made apparent by the description by Andersen (1912:700-701). _N. a. minor_ occurs about 1500 miles eastward of the place from which _N. a. draconilla_ Thomas, a subspecies essentially unknown to me, was named (see Laurie and Hill, 1954:46).

From _Nyctimene sanctacrucis_, known from the Santa Cruz Islands, _minor_ differs as follows: much smaller in all dimensions; forearm averaging 54.8 as opposed to 75; greatest length of skull 28.2 as opposed to 34.5; length of maxillary tooth-row 8.9 as opposed to 12.9.

[Ill.u.s.tration: FIG. 12. Distribution of _Nyctimene albiventer bougainville_ ([BC]) and _N. albiventer minor_ ([LW]).

For names of islands see Fig. 2.]

[Ill.u.s.tration: FIG. 13. Scatter diagram comparing two subspecies of _Nyctimene albiventer_. One individual of specimens thought to be intergrades is as large as specimens of _Nyctimene a.

bougainville_, whereas the other three intergrades are about the same size as specimens of _N. a. minor_. Symbols represent _N. a. bougainville_ ([BW]), _N. a. minor_ ([TW]), and intergrades a.s.signed to _minor_ ([BC]). For names of islands see Fig. 2.]

TABLE 3. Average and Extreme Measurements of _Nyctimene albiventer bougainville_ and _N. a. minor_.

===============+==================+==================+=================== _N. a. minor_ _Intergrades_ _N. a.

bougainville_ MEASUREMENT Choiseul, Fauro Kolombangara, Santa Ysabel Guadalca.n.a.l 4 [M], 1 [F] 1 [M], 3 [F] 8 [M], 1 [F]