Part 9

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 (1964a, 1964b) 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. hypomelanus, P. admiralitatum, P. tonganus, and P. howensis. The first and second species were placed in the Pteropus hypomelanus 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. mahaganus 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. mahaganus and P. woodfordi can be included in the Pteropus scapulatus group of Andersen (1912:402).

=Pteropus hypomelanus=

Pteropus hypomelanus is a wide-ranging species of flying fox having at least seven subspecies; three occur in southeastern Asia, two on and near Celebes, and two in New Guinea and islands adjacent to the southeastern coast of New Guinea, including one island in the Solomons (Ellerman and Morrison-Scott, 1966:95; Laurie and Hill, 1954:32-33).

=Pteropus hypomelanus luteus= Andersen

1908. Pteropus hypomelanus luteus Andersen, Ann. Mag. Nat. Hist., ser. 8, 2:362, October, type from Kiriwini Island, Trobriand Islands; 1912, Andersen, Catalogue of the Chiroptera ... British Museum, 1:128; 1947, Sanborn and Beecher, Jour. Mamm., 28:388, November 19, from Banika Island, Russell Islands.

Specimens examined.--None.

Remarks.--Andersen (1908:362) identified specimens of Pteropus hypomelanus from eastern New Guinea and three nearby islands (Conflict Islands, Trobriand Islands, and Woodlark Island) as P. hypomelanus luteus. Sanborn and Beecher (1947:388) identified a female from Banika Island in the Solomons as of this subspecies although this specimen was darker and had a slightly smaller skull than typical P. hypomelanus luteus. They noted that the pelage of the venter of the female was uniformly dark rather than the typical Ochraceous-Buff to Cream-Buff; the specimen was regarded as a dark phase of the subspecies. Although not recorded previously for luteus, other subspecies of P. hypomelanus were known in dark phase as well as pale and intermediate phases of coloration (Andersen, 1912:122). The reported occurrence of P. h. luteus on Banika Island extended the known geographic range about 450 miles eastward from Woodlark Island.

=Pteropus admiralitatum=

Three subspecies, all about the same size but differing in coloration, have been described from the Solomon Islands. P. a. goweri is known only from Gower (Ndai) Island, notably removed from the western chain of islands inhabited by P. a. colonus and P. a. solomonis. Only one other subspecies, from the Admiralty Islands, is known.

=Pteropus admiralitatum solomonis= Thomas

1904. Pteropus solomonis Thomas, Novit. Zool., 11:597, type from Ghizo Island; 1912, Andersen, Catalogue of the Chiroptera ... British Museum, 1:149; 1931, Sanborn, Publ. Field Mus. Nat. Hist., Zool. Ser., 18:12, February 12, from Ronongo (Ganongga), Vella Lavella, and Narovo (Simbo) islands; 1947, Sanborn and Beecher, Jour. Mamm., 28:389, November 19, from Banika and Guadalcanal islands.

1954. Pteropus admiralitatum solomonis, Laurie and Hill, List of land mammals of New Guinea, Celebes and adjacent islands, p. 33, June 30.

Specimens examined.--None.

Remarks.--Andersen (1912:149) considered Pteropus admiralitatum, and especially the subspecies P. a. solomonis, to be the easternmost "representative" of Pteropus hypomelanus. In comparison with P. hypomelanus luteus, P. a. solomonis differs mostly in size, being much smaller (length of forearm about 110 rather than 134). It is now known that both species occur on Banika Island in the Solomons.

The subspecies P. a. solomonis has been recorded from a "chain" of islands that included Vella Lavella, Simbo, Ghizo, Ganongga, Banika, and Guadalcanal (see Fig. 5).

=Pteropus admiralitatum colonus= Andersen

1908. Pteropus colonus Andersen, Ann. Mag. Nat. Hist., ser. 8, 2:363, October, type from Shortland Island; 1912, Andersen, Catalogue of the Chiroptera ... British Museum, 1:150; 1931, Sanborn, Publ. Field Mus. Nat. Hist., Zool. Ser., 18:12, February 12, from Mono Island.

1954. Pteropus admiralitatum colonus, Laurie and Hill, List of land mammals of New Guinea, Celebes and adjacent islands, p. 33, June 30.

1887. Pteropus hypomelanus (part), Thomas, Proc. Zool. Soc. London, p. 471, December 4; 1898, Trouessart, Catalogus Mammalium ..., 1:82, from "I. Salomonis."

1899. Pteropus (Spectrum) hypomelanus (part), Matschie, Die Megachiroptera ... naturkunde, p. 24.

Specimens examined.--None.

Remarks.--Pteropus admiralitatum colonus is the largest of the three subspecies that occur in the Solomon Islands. It closely resembles P. hypomelanus luteus, except in being smaller throughout (see Andersen, 1912:151-152, for measurements) and darker on the underparts.

This bat has been found in a group of small islands (Alu, Mono, and Shortland) about 30 miles south of Bougainville. Because of this proximity and because yet another subspecies of this species occurs northward of Bougainville, it is interesting that neither Troughton (1936) nor Pohle (1953) included the species in their faunal lists for Bougainville.

Andersen (1912:152) indicated that the M1 in P. admiralitatum colonus is smaller than in P. a. solomonis, the subspecies found in islands to the southeast (4.4-4.5 and 5.2, respectively), but Sanborn (1931:13) studied specimens of these two subspecies that overlapped in size of M1.

=Pteropus admiralitatum goweri= Tate