Part 13

Lawrence (1945:389) named Pteropus austini as a new species closely related to P. woodfordi and other species of the P. scapulatus group of Andersen (1912:402) and Tate (1942:336). Sanborn and Beecher (1947:389), studied a series of P. woodfordi from Banika and Guadalcanal and found that skulls of two subadults agreed well with cranial characteristics ascribed to P. austini, which was based on two subadults. Lawrence (1945:61) stated also that "the interfemoral membrane is entirely absent medially in austini, while in woodfordi it is present as a barely discernible ridge 8 mm. wide." Andersen (1912:408) had earlier reported that in the type of woodfordi the interfemoral membrane was "undeveloped in centre." In 13 adults (in alcohol) studied by Sanborn and Beecher (1947:389), as well as in adults examined by me, the uropatagium is not present. In size, however, these specimens agree with dimensions given for woodfordi by Thomas (1888a:156) and Andersen (1912:410); for example, length of forearm is 93-99. According to Lawrence (1945:59) austini, in which the interfemoral membrane is lacking, is smaller than woodfordi and has a forearm of about 84. In two juveniles of P. woodfordi in the U. S. National Museum, the medially-developed interfemoral membrane is about 7 wide. One specimen has small but distinct calcars whereas the other (slightly larger) apparently lacks calcars. This suggests individual variation in the presence or absence, as well as in the size, of the uropatagium in Pteropus woodfordi.

Sanborn and Beecher (1947:389) decided that "until fully adult specimens showing the characters of austini are available, it best be considered a synonym of woodfordi." For the following reasons I agree with these authors: (1) austini is known from only two specimens, both of which are apparently subadults; (2) austini is reported to have a forearm 84 long and no interfemoral membrane, whereas woodfordi has a forearm about 96 long and an interfemoral membrane that is only slightly developed; (3) specimens that agree in size and cranial characters with the type of woodfordi but that lack an interfemoral membrane have been obtained; and (4) skulls of subadults of woodfordi agree with the description of skulls of austini.

Sanborn (1931:19) reported that specimens of Pteropus woodfordi were obtained at night, while feeding on young green coconuts. Lawrence (1945:62) reported that in the late afternoon a collector found individuals of austini [= woodfordi] in the fronds of a coconut tree, apparently feeding on pollen shoots. Sanborn and Beecher (1947:388) have reported malaria (Plasmodium) in P. woodfordi obtained on Guadalcanal. They suggested that malaria might have rendered one individual helpless because when it was found, on the ground, no wounds were evident and parasites were present in the blood.

=Pteropus mahaganus= Sanborn

1931. Pteropus mahaganus Sanborn, Publ. Field Mus. Nat. Hist., Zool. Ser., 18:19, February 12, type from Santa Ysabel, also reported from Bougainville; 1954, Laurie and Hill, List of land mammals of New Guinea, Celebes and adjacent islands, p. 39, June 30.

Specimens examined (one male and two females; one in alcohol).--Bougainville, in August and October, USNM 276972, USNM 277104-5.

Measurements.--Measurements of one male and two females are, respectively, as follows: Length of head and body, 180, 204, 198; hind foot, 42, 38, 44; ear, 25, 23, 22; length of forearm, 134, 138, 140. Measurements of the skull of the male and one female are, respectively, as follows: Greatest length of skull, 52.5, 55.8; condylobasal length, 50.9, 54.3; palatal length, 24.1, 26.0; zygomatic breadth, 28.9, 32.5; breadth across first upper molars, 14.4, 15.0; width of M1, 2.2, 2.2; length of maxillary tooth-row, 17.4, 18.4; length of mandibular tooth-row, 20.1, 21.4.

Remarks.--Sanborn (1931:19-21) described Pteropus mahaganus on basis of six specimens, five from Santa Ysabel and one from Bougainville. The latter was in poor condition and only provisionally allocated to this species. The specimens examined by me (listed above) confirm the occurrence of P. mahaganus on Bougainville.

Sanborn (1931:20) described mahaganus as "similar to and about the size of [Pteropus scapulatus] from Australia, but lighter in color," and considered it, along with P. woodfordi, a member of the Pteropus scapulatus group of Andersen (1912:402) and Tate (1942:336). I would judge, however, that P. mahaganus and P. woodfordi are much more closely related to one another than to P. scapulatus of Australia. The only significant characteristic that the latter has in common with the two species from the Solomons is small cheek-teeth. In fact, teeth of scapulatus are relatively smaller than teeth of either mahaganus or woodfordi. Also, in scapulatus the upper canines are widely separated due to lateral expansion of the palate at that point, whereas in mahaganus and woodfordi the width across the upper canines is relatively much less.

=Dobsonia= Palmer

1898. Dobsonia Palmer, Proc. Biol. Soc. Washington, 12:114, April 30.

1810. Cephalotes (part) É. Geoffroy, Ann. du Mus. d'Hist. Nat., 15:104.

Dobsonia, a genus of large to medium-sized fruit bats, occurring from Celebes to the Solomon Islands, contains at least nine species. One species and its two subspecies are endemic to the Solomons.

Dobsonia differs from all other genera of megachiropteran bats in the Solomons by combining absence of a small claw on the second digit and presence of external tail vertebrae.

The cranium of Dobsonia resembles, in some ways, the cranium of Rousettus as well as that of Pteropus. Even so, in Dobsonia the rostrum is shorter and the cheek-teeth, especially in the upper jaw, are more crowded. The anterior part of the mandible is narrow and the lower incisors are diminutive and often concealed by the flesh of the gum.

=Dobsonia inermis=

In a review of the genus Dobsonia, Andersen (1909c:532) named and described D. inermis and D. nesea from the Solomons. Specimens of Dobsonia inermis from San Cristobal and Ugi were said to differ from specimens of D. nesea from Alu, Shortland, and Rubiana in having perpendicular as opposed to anteriorly slanted upper canines. Andersen (1909c:532) reported that the two species were of "... the same general size." Troughton (1936:348-349) studied specimens of Dobsonia from Bougainville and Santa Ysabel and, because of individual variation in proclivity of the upper canines, concluded that D. nesea was conspecific with D. inermis. He (p. 349) noted that the ears were shorter in inermis than in nesea, but the size of teeth showed insular variation and a "... confusing amount of intergradation ... [that obscures] ... diagnostic importance."

Specimens of Dobsonia from Choiseul are smaller (externally and cranially) than those from Alu, Shortland, Rubiana, Bougainville, Fauro, Vella Lavella, Guadalcanal, Florida, Ugi, San Cristobal, and Rennell. Specimens from Santa Ysabel (see Fig. 8) are intermediate in size between those from Choiseul and the other islands listed. Judging from available specimens, two subspecies of Dobsonia inermis occur in the Solomons. Specimens from Choiseul (see A, Fig. 8), which are smaller than those from other islands, represent one subspecies (heretofore unrecognized), whereas specimens from other islands (except Santa Ysabel) represent a second subspecies. Specimens from Santa Ysabel are slightly larger than those on Choiseul and are regarded as intergrades between the two subspecies. Specimens from Rennell, Ugi, San Cristobal, Florida, Fauro, and Guadalcanal are slightly smaller than those from Bougainville, Vella Lavella, Shortland, and Rubiana, but the differences are not great enough to warrant recognition of two subspecies. Therefore, the subspecific name nesea is arranged as a synonym of inermis, which has priority, and the latter name is used for specimens of Dobsonia inermis from the Solomon islands other than Choiseul and Santa Ysabel. Additional remarks on the distribution of this species are in the section on Zoogeography and Speciation.

Pohle (1953:130) suggested that Dobsonia inermis (as well as D. crenulata and D. praedatrix) is conspecific with D. viridis, but Laurie and Hill (1954:41) did not adopt his suggestion. I have not seen adequate series of crenulata, praedatrix, and viridis (none of which occurs in the Solomons) to judge systematic relationships of these kinds; therefore I follow Laurie and Hill.

=Dobsonia inermis inermis= Andersen

1909. Dobsonia inermis Andersen, Ann. Mag. Nat. Hist., ser. 8, 4:532, December, type from San Cristobal; 1912, Andersen, Catalogue of the Chiroptera ... British Museum, 1:475.

1936. Dobsonia inermis inermis, Troughton, Rec. Australian Mus., 14:349, April 7, from Santa Ysabel; 1954, Laurie and Hill, List of land mammals of New Guinea, Celebes and adjacent islands, p. 41, June 30; 1956, Hill, The natural history of Rennell Island, British Solomon Islands, 1:74, November 28, from Rennell Island.

1878. Cephalotes peroni (part), Dobson, Catalogue of the Chiroptera ... British Museum, p. 91; 1879, Trouessart, Rev. Mag. Zool., 3:208; 1887, Thomas, Proc. Zool. Soc. London, p. 323, March 15, from Ugi and San Cristobal; 1888, Thomas, Proc. Zool. Soc. London, p. 476, December 4; 1897, Trouessart, Catalogus Mammalium ..., 1:87.

1899. Dobsonia peroni (part), Trouessart, Catalogus Mammalium ..., 2:1278.

1909. Dobsonia nesea Andersen, Ann. Mag. Nat. Hist., ser. 8, 4:532, December 1, type from Shortland Island; 1912, Andersen, Catalogue of the Chiroptera ... British Museum, 1:476, from Shortland and Rubiana; 1931, Sanborn, Publ. Field Mus. Nat. Hist., Zool. Ser., 18:22, February 12, from San Cristobal.

1936. Dobsonia inermis nesea, Troughton, Rec. Australian Mus., 14:348, April 7, from Bougainville; 1953, Pohle, Z. Säugetierk., 17:130, October 27; 1954, Laurie and Hill, List of land mammals of New Guinea, Celebes and adjacent islands, p. 41, June 30, from New Georgia.

Specimens examined (13 males and three females; three in alcohol, crania extracted and cleaned).--Fauro in April, 23728, 23740, 23751; Vella Lavella in November, 23134-36, 23141, 23145, 23147, 23149, 23151, 23153; Guadalcanal in May and June, 23865, 23914, 24008; Florida in October, 24416.

Measurements.--See tables 2 and 3.