Carleton J. Phillips

“ Generally, more subspecies are known from the larger islands than from the smaller islands (Guadalcanal with 5, Bougainville, Choiseul, and Santa Ysabel with 4, Fauro with 2.) The distributions of some subspecies can be used to judge the differential effectiveness of water gaps between islands. ”

“ The distributions of 16 species of megachiropterans known from the Solomons are summarized in Table 5 and in Figure 16. The larger islands (in terms of surface area and elevation) in general [827] have the highest number of species (Guadalcanal 10, Choiseul 9, and Bougainville 8) . But Fauro, one of the smallest islands for which data are available, has six species of megachiropterans whereas San Cristobal and Malaita, two of the larger islands, have only three and four species, respectively. ”

“ This situation resembles the one involving Fauro, Bougainville, and Choiseul because none of the large bats (Pteropus and Pteralopex) is known from Florida, even though two species of large bats that occur on Santa Ysabel to the northwest occur also on Guadalcanal to the south. Possibly Florida and the smaller islands that comprise the Nggela Group are ecologically unsuitable for large bats, or perhaps these small islands can support only limited numbers of individuals during part of a year. ”

“ Some of the small islands in the Solomons have populations of large fruit bats. For example, Pteropus admiralitatum and P. hypomelanus have been reported from the small islands in the Russell Group (Table 5) . Possibly these species do not live concurrently in the Russells; specimens of the two were obtained in different years. Two small megachiropterans, P. woodfordi and Melonycteris woodfordi, also inhabit the Russells. Shortland, a small island about 15 miles south of Bougainville, supports one large bat, P. admiralitatum, as well as smaller megachiropterans. ”

“ Variability of number of incisors in the upper jaw of specimens of Melonycteris (and in other macroglossine genera, as well) indicates a lack of selective pressure for either increase or decrease in number of incisors. Furthermore, the loss of the small claw on the second digit might not be important because, as Bader and Hall (1960:15) have pointed out, limbs of bats vary more in phenotypic expression than do other parts of the skeletal structure.
[815]
The discovery of a new species (Melonycteris aurantius) in the Solomon Islands sheds additional light on the problem. ”

“ Australia and New Guinea have many kinds of mammals but the only terrestrial mammals in the Solomon Islands are a species of the genus Phalanger (order Marsupialia) , and several species of four genera of rodents, one genus of which probably was introduced by man. Additionally, several kinds of bats have reached and colonized the Solomon Islands. ”

“ Most islands of the Solomon Group support dense tropical rain forest. Much of it has been modified by man. Some clearings and scattered coconut plantations are found along coasts. On some of the larger islands (for example, Guadalcanal) coastal scrub (especially on leeward coasts) and extensive grassy areas are to be found. ”

“ Remarks.—The specimens from Choiseul, Kolombangara, and Malaita islands provide new records of distribution for Rousettus amplexicaudatus hedigeri (Fig. 3) . It was described as smaller than R. a. brachyotis Dobson, which is known from New Guinea, Amboina, and the Bismarck Archipelago (Pohle, 1953:127-128) . Andersen (1912:809) gave the range of length of forearm in R. a. brachyotis as 73-81, whereas Pohle (1953:127) gave the length of forearm of the type specimen of R. a. hedigeri (adult male) as 67. ”

“ 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 Guadalcanal, minor differs as follows: averaging slightly smaller in all dimensions; forearm averaging 54.8 as opposed to 57.9 ”

“ Rousettus amplexicaudatus, Pteropus rayneri, P. woodfordi, Macroglossus lagochilus, and Nyctimene albiventer have been collected on Kolombangara but only P. admiralitatum, P. rayneri, and Dobsonia inermis have been found on Vella Lavella. The difference in the known megachiropteran faunas is more striking when one compares each island with adjacent islands. Two species on Vella Lavella occur also on Choiseul, which is about 35 miles northeastward, and two species occur also on Shortland, which is 120 miles northwestward (Fig. 16) . ”

“ If this formula is applied here, one finds that winds from the southeast (that is, from the New Hebrides and New Caledonia) would have to be more than 100 times more [833] favorable than winds from the northeast (from Guadalcanal and San Cristobal) in order to compensate for the distance of Rennell from the New Hebrides and New Caledonia. Even so, tropical storms with unusually strong winds, frequent during some parts of the year, possibly account for the present distributional pattern of bats and birds that live on Rennell. ”

“ These native peoples are notorious for their cannibalistic tendencies; the eating of human flesh usually was related to warfare, although malefactors and human sacrifices accounted for some of the cannibalism (Cranstone, 1961:29) . Prior to the Second World War few Europeans visited the Solomons and several islands still remain beyond reach of modern-day technology. For example, Rennell and Bellona islands, south of the main part of the archipelago, are visited only rarely, and then only by a medical officer or the Resident Commissioner. ”

“ 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 labial surface, whereas in the type it does not; and maxillary and mandibular teeth in adults are spaced 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. ”

“ Distribution of Pteropus rayneri: P. r. rayneri () ; P. r. grandis () ; P. r. lavellanus () ; P. r. monoensis () ; P. r. rubianus () ; P. r. cognatus () ; P. r. rennelli () . For names of islands see Fig. 2.
Adult males of Pteropus rayneri have well-developed tufts of hair on each [800] side of the neck where a gland is located (see Andersen, 1912:259) . Apparently these glands are not present in females as none were found in specimens studied by me or those reported by Sanborn (1931:16) . ”

“ 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 constitute a new locality of occurrence for the species. Apparently M. woodfordi occurs throughout the Solomons (see Fig. 11) .
Thomas (1887a:147) named Nesonycteris woodfordi in a preliminary report that appeared before the publication of the more detailed description of the genus and species (1887b:323-324) . ”

“ It is divisible into seven subspecies (see Fig. 6) , which, excepting P. r. rennelli and P. r. cognatus, are strikingly colored—the mantle, back, and rump being of different colors. Differences in color and size provide characters differentiating the subspecies (see key, p. 793) . Recorded lengths of forearms do not overlap between any two subspecies. P. r. grandis, northernmost in distribution, has the longest (about 170) forearm and P. r. cognatus, known from two of the southernmost islands, has the shortest (about 121) . ”

“ In 1932, Lewis (1951:37) felt that the natives of Malaita Island were especially resistant to outside interference by Caucasians and reported that no "white man or foreigner" was safe on Malaita.
Troughton (1936) , who listed Melanesian names for mammals, indicated that the native peoples distinguished between kinds of bats that closely resembled one another. Of these, the only bats that seem to be used as food belong to the genus Pteropus.
GAZETTEER
In the following list, currently-used names of islands are given ”

“ Remarks.—Nyctimene major scitulus has been recorded only from the western chain of islands in the Solomons (see Fig. 15) . Specimens examined by me agree well in external dimensions and color with specimens described by Andersen (1912:712) and Troughton (1931:206-207) .
ZOOGEOGRAPHY AND SPECIATION
De Beaufort (1951:113) considered bats of "less zoogeographical importance" than other mammals because the ocean is not an "absolute barrier to their dispersal." ”

“ Measurements of the male examined are greater than those of the female studied. Andersen (1912:259) noted that the canine teeth are heavier in males than in females.
Pteropus rayneri monoensis Lawrence
1945. Pteropus rayneri monoensis Lawrence, Proc. New England Zool. Club, 23:63, March 26, type from Mono (Treasury) ; 1954, Laurie and Hill, List of land mammals of New Guinea, Celebes and adjacent islands, p. 36, June 30.
Specimens examined.—None.
Remarks.—Pteropus rayneri monoensis is the most recently described subspecies of P. rayneri. ”

“ It is also the widest ranging subspecies, being found on six islands (see Fig. 6) .
Although the specimens listed above agree well with descriptions of color given by Thomas (1887a:147) and Andersen (1912:259, 263-264) , some individual variation is noticeable. In bats not yet fully grown (judging from small size, unfused epiphyses, and lack of wear on teeth) , numerous scattered hairs on the sides of the face and crown are buffy. In adults the face and crown are blackish. ”

“ They [individuals of P. r. monoensis] rest quietly during the day in the tops of heavy-leaved, tall jungle trees, and start flying about dusk, looking for feeding spots. There is usually quite a flight for fifteen to twenty minutes at twilight.... ”

“ ALU.—7° 07' S, 155° 54' E.
BANIKA.—9° 05' S, 155° 13' E.
BARA (Gera) .—9° 31' S, 160° 31' E.
BELLONA (Bello) .—11° 18' S, 159° 48' E.
BOUGAINVILLE (Mamamolimo) .—6° 12' S, 155° 15' E. This is the largest island in the Solomon Group, being 127 miles long (northwest to southeast) and about 59 miles across at the widest place. The highest elevations are 9850 and 10171 feet, at the tops of active volcanoes. Ecologically, Bougainville is mostly dense rain forest, which is less dense on the summits of higher mountains. ”

“ Although adults of minor average only slightly smaller than adults of bougainville (see Table 3) , there is only slight overlap (about 0.2 at most) in most minimum dimensions of external and cranial features of bougainville and corresponding maximum dimensions of externals and crania of minor. The difference in size is clearly shown in Figs. ”

“ Mammals of Nevada. Univ. California Press, Berkeley, xi + 710 pp., frontispiece, 11 pls., 485 figs., July 1.
Hill, J. E.
1956. The mammals of Rennell Island. The natural history of Rennell Island, British Solomon Islands, Copenhagen, 1:73-84, November 28.
1962. A little-known fruit-bat from Rennell Island. The natural history of Rennell Island, British Solomon Islands, Copenhagen, 4:7-9, February 15.
1963. A revision of the genus Hipposideros. Bull. British Mus. (Nat. Hist.) ”