Systematics of Megachiropteran Bats in the Solomon Islands Part 3

_Remarks._--_Pteralopex atrata atrata_ is known from four specimens from Guadalca.n.a.l and one from Santa Ysabel (Sanborn, 1931:21).

Sanborn (_loc. cit._) reported that a specimen wounded at night, while feeding on young green coconuts, was the only fruit bat that attempted to attack the collectors. Troughton (1936:348) has suggested, on the basis of his experiences with _Pteropus_, that this behavior probably was a reaction from fear rather than an indication of general aggressiveness on the part of _Pteralopex_.

=Pteralopex atrata anceps= Andersen

1909. _Pteralopex anceps_ Andersen, Ann. Mag. Nat. Hist., ser. 8, 3:266, March, type from Bougainville; 1912, Andersen, Catalogue of the Chiroptera ... British Museum, 1:437; 1936, Troughton, Rec. Australian Mus., 14:348, April 7; 1953, Pohle, Z. Saugetierk., 17:129, October 27.

1954. _Pteralopex atrata anceps_, Laurie and Hill, List of land mammals of New Guinea, Celebes and adjacent islands, p. 40, June 30.

_Specimens examined_ (three males, two females; one skull-only and one in alcohol).--Choiseul in March, 23682; Bougainville in July, USNM 276973-74, USNM 276928, USNM 277112.

_Measurements._--Measurements of three males and one female are, respectively, as follows: Length of head and body, 280, 271, 261, 255; hind foot, 50, 54, 52, 59; ear, 23, 23, 26, 22; length of forearm, 160, 162, 166, 171; greatest length of skull, 77.6, 77.9, 78.9, 77.0; condylobasal length, 74.3, 74.3, 75.5, 73.8; zygomatic breadth, 42.2, 45.4, 43.1, 42.6; breadth across upper canines, 18.7, 21.1, 19.0, 19.0; breadth across first upper molars, 22.2, 25.3, 22.9, 22.0; length of maxillary tooth-row, 29.3, 29.8, 28.9, 28.2; length of mandibular tooth-row, 32.8, 32.8, 32.1, 31.4.

_Remarks._--Heretofore, _Pteralopex atrata anceps_ was not known from Choiseul. The specimen from that island agrees well with specimens in the U. S. National Museum from Cape Torokina, Bougainville.

The type specimen of this subspecies is a subadult and is smaller than the specimens examined by me; Andersen (1912:440) gave length of forearm of the type as 137 (as opposed to 164 in adults). He (1912:438) figured the dent.i.tion of _anceps_ and described the ways in which it differed from the dent.i.tion of _atrata_. Although he (1912:437) concluded that _anceps_ and _atrata_ represented "two stages of specialization of ...

dent.i.tion," there apparently are few, if any, dental differences between the two subspecies. Teeth of adults of _anceps_ differ from teeth of the immature type of _anceps_ as follows: in adults the anterior basal ledge of P4 extends onto the l.a.b.i.al surface, whereas in the type it does not; and maxillary and mandibular teeth in adults are s.p.a.ced as in the subspecies _atrata_ (see Andersen, 1912:438, fig. 22) and not crowded as in the type of _anceps_. Distance between individual cheek-teeth apparently increases with growth of the cranium and mandible.

Adults of _P. a. anceps_ that I examined are darker than the subadult type. The mantle in these adults is black, whereas it is seal-brown in the type (Andersen, 1912:439).

An adult female was lactating when obtained on Bougainville in July (USNM 276928).

Key to _Pteropus_ in the Solomon Islands

1. Premolars having distinct basal ledges; molars 2.5-4.0 wide 2

1'. Premolars lacking definite basal ledges; molars 1.0-2.4 wide 14

2(1). Rostrum unshortened (orbit to anterior tip of nasals about one-third greatest length of skull); dorsal surface of tibiae nearly naked 3

2'. Rostrum shortened (orbit to anterior tip of nasals less than one-third greatest length of skull); dorsal surface of tibiae usually at least partially furred 8

3(2). Forearm more than 128 4

3'. Forearm less than 128 5

4(3). Forearm about 155; venter and dorsum nearly black, mantle pale yellow =P. tonga.n.u.s geddiei=, p. 798

4'. Forearm 128-136; venter and dorsum near Mars Brown, mantle Ochraceous or Cream-Buff =P. hypomela.n.u.s luteus=, p. 796

5(3'). Mantle dark, russet or cinnamon, not strongly contrasting with color of back =P. admiralitatum solomonis=, p. 796

5'. Mantle pale, Ochraceous-Buff or Cream-Buff, strongly contrasting with color of back 6

6(5'). Mantle Ochraceous-Orange to Ochraceous-Buff, hairs pale basally; forearm 108-111 =P. admiralitatum goweri=, p. 797

6'. Mantle Ochraceous to Cream-Buff, but hairs dark brown basally; forearm 110-122 7

7(6'). Length of forearm 110-112 =P. admiralitatum colonus=, p. 796

7'. Length of forearm about 122 =P. howensis=, p. 797

8(2'). Forearm more than 145 9

8'. Forearm less than 144 12

9(8). Forearm more than 162 10

9'. Forearm less than 162 11

10(9). Forearm 167-173 =P. rayneri grandis=, p. 801

10'. Forearm about 164 =P. rayneri rubia.n.u.s=, p. 802

11(9'). Flanks and lower belly brightly colored, Burnt Sienna to Sanford's Brown; forearm less than 150 =P. rayneri monoensis=, p. 803

11'. Flanks and lower belly darker, near tawny; forearm more than 150, =P. rayneri lavella.n.u.s=, p. 802

12(8'). Pelage of dorsum tricolored; rump brightly colored; forearm 139-141, =P. rayneri rayneri=, p. 800

12'. Pelage of dorsum bicolored; rump dark; forearm less than 135 13

13(12'). Mantle tawny with some Ochraceous-Buff; forearm about 130, =P. rayneri rennelli=, p. 804

13'. Mantle russet, lacking Ochraceous-Buff; forearm about 121, =P. rayneri cognatus=, p. 803

14(1'). Forearm more than 131; dorsum Tawny Olive =P. mahaga.n.u.s=, p. 806

14'. Forearm less than 100; dorsum dark brown =P. woodfordi=, p. 804

=Pteropus= Brisson

1762. _Pteropus_ Brisson, Regnum animale ..., ed. 2, p. 153.

_Remarks._--More species (seven) and subspecies (12) of _Pteropus_ occur in the Solomon Islands than of any other chiropteran genus. Other kinds of _Pteropus_, as yet unknown, may live there.

The relationships among the species of these large fruit-eating bats, commonly termed "flying foxes," are obscure and the genus is in need of revision. The basic, definitive work is still that of Andersen (1912).

Tate (1942) and Felten (1964_a_, 1964_b_) have offered some additional remarks but groupings and suggested relationships of species of _Pteropus_ almost entirely are the products of Kund Andersen. According to present-day concepts of variation and speciation, Andersen's criteria are artificial.

Basically, there are three "species-groups" of _Pteropus_ in the Solomon Islands. The first is composed of species in which the rostrum is "unshortened" (its length about one third of greatest length of skull), and the cheek-teeth are of moderate size (M1 is 2.8-3.2 wide). The species are _P. hypomela.n.u.s_, _P. admiralitatum_, _P. tonga.n.u.s_, and _P.

howensis_. The first and second species were placed in the _Pteropus hypomela.n.u.s_ group by Andersen (1912:98).

In the second group the rostrum is "shortened" (its length less than one third of greatest length of skull) and the cheek-teeth are of moderate to large size (M1 3.3-4.1 wide). _Pteropus rayneri_, endemic to the Solomons and represented there by at least seven subspecies, fits into this category.

The third group is represented by _P. mahaga.n.u.s_ and _P. woodfordi_.

Both species are endemic to the Solomon Islands. In these species the rostrum is unshortened but the cheek-teeth are greatly reduced, especially in width (M1 is 1.0-2.2 wide). Both _P. mahaga.n.u.s_ and _P.