Part 17

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 papuanus bougainville, Pohle, Z. Säugetierk., 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); Guadalcanal 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 Guadalcanal. The subspecies apparently ranges throughout the western chain of the Solomons.

Troughton (1936:350) considered Nyctimene bougainville specifically distinct from its nearest ally, N. papuanus. 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. papuanus. Laurie and Hill (1954:46) synonymized bougainville and papuanus with N. albiventer. However, Troughton (1936:350) pointed out that in addition to size bougainville differed from papuanus by having narrower and longer pm3 and pm4. Judging from specimens examined by me, such is the case, and the difference is even more pronounced in m1.

Specimens of N. a. bougainville from Kolombangara and Guadalcanal 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 sex.

Nyctimene albiventer from Choiseul and Santa Ysabel is smaller, in all respects, than N. albiventer from Bougainville, Kolombangara, and Guadalcanal (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 sparsely 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 sparsely 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). Sexually dichromatic as follows: male--dorsum Hair-Brown, bases of hairs darker; hair on throat sparse, 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 sparse, 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 Guadalcanal, 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 papuanus, 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.

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 | | Guadalcanal | 4 , 1 | 1 , 3 | 8 , 1 ---------------+------------------+------------------+------------------- Length of head | | | and body |107.0 (105 -109 )|109.2 (105 -112 )|110.0 (106 -117) Tail vertebrae | 20.0 (19.3- 20.5)| 21.0 ( 20 - 22 )| 19.2 ( 15.5- 23.0) Hind foot | 14.2 (13.5- 15.0)| | 14.3 ( 13.0- 15.9) Ear | 11.9 (11.0- 13.0)| | 12.8 ( 11.8- 14.5) Length of | | | forearm | 54.8 (54.0- 55.8)| 57.1 (55.9- 59.0)| 57.9 ( 55.8- 59.8) Greatest | | | length of | | | skull | 28.2 (27.2- 28.9)| 28.6 (28.3- 29.7)| 29.7 ( 28.6- 30.1) Condylobasal | | | length | 26.7 (26.2- 27.5)| 27.4 (26.6- 28.0)| 28.0 ( 27.8- 28.9) Palatal length | 11.2 (10.9- 11.9)| 11.6 (11.3- 11.8)| 11.7 ( 11.0- 12.5) Breadth of | | | braincase | 12.0 (11.5- 12.4)| 12.0 (11.7- 12.2)| 12.3 ( 12.1- 12.8) Zygomatic | | | breadth | 18.9 (18.4- 19.7)| 18.6 (18.4- 19.2)| 19.2 ( 18.7- 20.0) Interorbital | | | breadth | 5.0 ( 4.7- 5.6)| 5.3 ( 5.0- 5.6)| 5.1 ( 4.7- 5.5) Breadth across | | | first upper | | | molars | 8.6 ( 8.4- 8.9)| 8.9 ( 8.7- 9.1)| 9.1 ( 8.8- 9.6) Maxillary | | | tooth-row | 8.9 ( 8.7- 9.3)| 9.3 ( 9.1- 9.5)| 9.5 ( 9.2- 9.8) Mandibular | | | tooth-row | 10.3 (10.0- 10.6)| 10.5 (10.2- 11.1)| 10.9 ( 10.7- 11.4) ---------------+------------------+------------------+-------------------

Measurements.--Measurements of the two subspecies from the Solomons are given in Table 3. Some measurements of the type are as follows: Length of head and body, 108; tail vertebrae, 20.5; hind foot, 14.7; ear, 11.3; length of forearm, 55.1; 2nd metacarpal, 27.4; 3rd metacarpal, 39.0; 4th metacarpal, 37.5; 5th metacarpal, 39.1; greatest length of skull, 28.6; condylobasal length, 27.5; zygomatic breadth, 18.4; length of maxillary tooth-row, 9.0; length of mandibular tooth-row, 10.4.

Remarks.--Nyctimene albiventer minor closely resembles N. albiventer bougainville, differing from the latter mostly in size. 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. 13 and 14.

Four specimens of Nyctimene albiventer from Fauro herein are considered to be intergrades between N. a. bougainville and N. a. minor. As shown in Table 3, the specimens from Fauro average slightly larger than those of minor from Choiseul and Santa Ysabel and slightly smaller than specimens of bougainville from Kolombangara and Guadalcanal. I have assigned the specimens from Fauro to N. a. minor because they generally are closer to minor in size (see Fig. 13).

Specimens examined (five males and four females; seven in alcohol; seven crania extracted and cleaned).--Choiseul in February and March, 23636 (holotype), 23631, 23540, 23646; Santa Ysabel in February, 23539; Fauro in April, 23742, 23743, 23763, 23764.

One specimen of Nyctimene from Malaita Island is smaller than Nyctimene major, which is known from Shortland, Alu, Florida, New Georgia, Guadalcanal, Choiseul, and Malapa (see Fig. 15) and is larger than either of the two subspecies of Nyctimene albiventer known from Bougainville, Fauro, Kolombangara, Guadalcanal, Choiseul, and Santa Ysabel. This specimen represents a previously unknown species and may be named and described as follows:

=Nyctimene malaitensis=, new species

Type.--Adult female, skin and skull, in good condition (originally stored in alcohol for about one year), no. BSIP 24103, Bernice P. Bishop Museum; from Malaita Island, British Solomon Islands Protectorate; obtained on 1 July 1964, by Peter Shanahan, original no. unknown.

Distribution.--Known only from Malaita (see Fig. 16).