AMERBICAN MUSEUM NOVITATES Published by Number 1101 THE AMERICAN MUSEUM OF NATURAL HISTORY January 30, 1941 New York City RESULTS OF THE ARCHBOLD EXPEDITIONS. No. 31 NEW RODENTS AND MARSUPIALS FROM NEW GUINEA BY G. H. H. TATE AND RICHARD ARCHBOLD The large collection of mammals assem- mouth of the Fly River. Thence stations bled by the Archbold Expeditions of 1936 were established all the way up the Fly and 1938 to New Guinea, contains many River and into the Central Mountain interesting novelties, some of which are range to an altitude of nearly 1000 meters. here described. Work was done also along the south coast The 1938 party made its base at Hol- of the Western Division of Papua at landia on the north coast of the island Mabadauan and Strachan Island, and in whence, using a large aeroplane, it estab- the Central Division northeast of Port lished field bases on the Idenburg River Moresby up to Kagi, 1600 meters. and on Lake Habbema (3300 meters), on The mammals brought back by the 1938 the northern slopes of Mt. Wilhelmina. Expedition were collected by W. B. From Bernhard Camp (60 meters), the Richardson; those of the 1936 Expedition base on the Idenburg, subsidiary stations by G. H. H. Tate. Both Richardson and were occupied up the slopes to the crest of Tate employed native collectors to help the range south of the river, the altitudes them. Measurements, unless otherwise of which were recorded as 850, 1200, 1800, stated, were taken by Richardson or Tate. 2100 meters, respectively. Colors printed with capitals are those of From Lake Habbema two main lines of Ridgway.2 camps were prepared. One chain of sta- tions reached downward, following the PARALEPTOMYS, NEW GENUS courses of the Bele and Balim Rivers This genus needs comparison only with Lep- (with drainage to the south coast of New tomys, from which it is separated by its normal Guinea)-through altitudes of 2800, 2200 hind foot (elongated in Leptomys), and by the absence of m3-.3 and 1600 meters. A second series of sta- GENOTYPE.-Paraleptomys wilhelmina. tions passed to the eastern side of Mt. Wilhelmina and then drove upward to new species collecting stations at 3560 and 3800 meters. Paraleptomys wilhelmina, TYPE.-No. 150512, Amer. Mus. Nat. Hist.; Thus the entire northeastern fall from Mt. adult d; 9 kilometers NE. of Lake Habbema, Wilhelmina was ransacked for species at near Mt. Wilhelmina, Netherlands New Guinea; all elevations between 60 and 4000 meters. altitude 2800 meters; October 15, 1938; collec- The new forms come chiefly from the tor, W. B. Richardson (field No. 5143), 1938 New Guinea Expedition. The type is a skin heavy lowland forests of the Idenburg with skull in good condition. River where they seem to have been rare GENERAL CHARACTERS.-Superficially very and are represented often by single speci- like certain brownish-gray mountain inhabiting mens; and from the high country above Melanomys. Differs sharply from Leptomys (with elongate feet and pure white ventral hairs), 2000 meters, in which case large series are from Pseudohydromys (shrew-like), and from available for study. Microhydromys (Mus-like). The 1936 expedition1 placed its head- DESCRIPTION OF TYPE.-Skin dorsally colored quarters on the Island of Daru near the near Bone Brown, very slightly intensified along the back; ventrally dull white, with gray bases ' For full report see Rand, A. L., and L. J. Brass, 1940, Bull. Amer. Mus. Nat. Hist., LXXVII, No. 29, 2 Ridgway, 1912. Color Standards and Nomen- pp. 341-380. clature. 2 AMERICAN MUSEUM NOVITATES [No. 1101 which amply show through the white tips. Ears connecting the Doorman Top ranges with large, gray; hands and feet thinly covered with whitish hairs. Tail light fuscous above, white the Wilhelmina uplands. beneath, its terminal 1.5 cm. white. Tail-scales MICROHYDROMYS, NEW GENUS simple, flat, rounded to slightly hexagonal, 14 per cm. Scale-hairs 3 per scale, about one scale- The smallest known Hydromyine, ahd unique length, whitish. Skull: in many respects very in possessing grooved upper incisor teeth. Pel- like Leptomys; rostrum, braincase, zygomatic age, ears, tail and lips without modifications for plate, palate, pterygoid region and bullae are aquatic habitus. Feet neither modified for essentially the same. Differs in the absence of swimming nor elongate as in Leptomys. Skull m' exhibiting the short, broad muzzle and widened (reduced but still 3-rooted in Leptomy8), and interorbital region and braincase of Para- the diminution of flare of the maxillary root of hydromys, but the bullae, although low, are very the zygoma. much larger and proportionally much closer to- MEASUREMENTS OF TYPE.-Skin: total gether (width of bullae, 2.9; distance apart of length, 261 mm.; tail, 135; hind foot (s.u.), 31; bullae, 2.0); zygomatic plate essentially as ear from crown, 17. Skull: condylo-incisive Hydromys and Pseudohydromys; palatal foramina length, 29.2; zygomatic breadth, 16.0; length of more as in Leptomys, less shortened than in nasals, 12; interorbital breadth, 5.7; breadth of Hydromys; nasals unshortened. interparietal, 7.3; breadth of braincase, 13.5; TEETH.-Upper incisors with distinct groove height of muzzle at level of front of incisive separating anterior face of tooth into an outer foramina, 5.8; palatal length, 14.5; palatal third and an inner two-thirds. Molars reduced foramina, 4.8 X 2.3; diastema, 7.6; breadth to two in each row, as in most Hydromyinae, but between ml-1, 2.9; breadth of mesopterygoid the toothrows wider spaced in the palate and less fossa, 2.1; bulla, 4.9 X 3.6; width between convergent anteriorly than in Parahydromys and bullae, 4.0; mastoid width, 12.2. Teeth: Hydromys, the arrangement being essentially length mI + Mi2, 4.5; mi1, 3.0 X 1.8; Mi2, 1.6 X that of Pseudohydromys. 1.5; ml + m2, 4.6; ml, 2.7; m2, 1.8. GENOTYPE.-Microhydromy8 richardsoni. Assumption by m2 of the terminal posi- Microhydromys richardsoni, new species tion in the toothrow has so modified its TYPE-.NO. 152079, Amer. Mus. Nat. Hist.; form that the postero-external tubercle adult d; 4 kilometers SW. of Bernhard Camp, has been eliminated. In Paraleptomys ml Idenburg River, Netherlands New Guinea; differs from that of in altitude 850 meters; March 16, 1939; collector, Leptomys being W. B. Richardson (field No. 7677), 1938 New slightly broader. But a more important Guinea Expedition. The type is a skin in good difference is observed in the relatively condition, and skull with braincase badly broken. great depth of the fissures separating the GENERAL CHARACTERS.-A blackish murid laminae of seen from the outer about the size of a housemouse, externally un- three ml, specialized; with terminal centimeter of tail face of the tooth. Said fissures reach a white. depth of 0.5 mm.-virtually to the level DESCRIPTION.-Skin: pelage dorsally deep of the cingulum. In Leptomys the fissures fuscous, the hairs quite short (5 mm.), ventrally either do not at all or remain very slightly lighter and hairs slightly shorter. develop Ears neither reduced nor enlarged, gray. Feet minute (0.2). and hands slender, thinly clad with short blackish Paraleptomys wilhelmina is represented hairs. Feet unwebbed and the soles lacking the granular structure of Parahydromys and Hy- in the collection obtained by Mr. Richard- dromys. Tail blackish above and below, the son by almost 50 specimens, all from the terminal cm. white. Scales rectangular; per Lake Habbema region between 2200 and cm. 15. Scale-hairs fine, short, blackish, about 3000 meters. A second series of 30 speci- 1 1/2 scale-lengths. Skull: short and broad, with the general appearance of a tiny Para- mens from camps on the heights(1800-2100 hydromys skull. Muzzle short and heavy; meters) SW. of Bernhard Camp between nasals unshortened (but slightly exceeded by the Idenburg River and its affluent, the pmx.); interorbital width unconstrieted, at- Hablifoert River, may be separable as a taining half of zygomatic width; brainease broad and full (broken); zygomatic plate excised faintly differentiated race. This slight in front (as in most Hydromyinae); palate about difference is inconstantly manifested by as broad as Pseudohydromys (its posterior part the form of the anterior margin of the missing), and palatal foramina larger than in zygomatic plate; less excised in the Iden- Hydromys, their length 50 per cent of diastema; bullae larger in proportion than in any other burg animals, more excised in the Habbema known Hydromyine genus, width of bulla more race. The two areas of distribution are than one-third of combined width across bullae made continuous by way of the highlands and included basioccipital. RESULTS OF THE ARCHBOLD EXPEDITIONS. NO. 31 3 MEASUREMENTS.-Skin: total length, 172 the toothrows are somewhat more widely spaced, mm.; tail, 92; hind foot (s.u.), 20; ear from the width between ml' being rather more than crown, 8. Skull: length of nasals, 6.4; width twice the width of ml. Also the palatal foramina of nasals anteriorly, 2.6; width muzzle just an- are slightly less shortened, remaining nearly 50 terior to zygomatic plate, 4.2; least interorbital per cent of diastema. width, 4.4; mastoid width, 9; approximate MEASUREMENTS.-Skin: total length, 317 zygomatic width, 9.2; palatal length, approxi- mm.; tail, 170; hind foot, 36; ear (s.u.), 9.1 mately 10; palatal foramina, 2.5 X 1.5; dia- Skull: condylo-incisive length, 33.3; zygo- stema, 5; bullae, 3.8 X 2.9; distance apart of matic width, 17.4; least interorbital width, 5.6; bullae, 2; distance between ml-', 2.3; length width of brainease, 15.6; length of nasals, 11.2; ml + m2, 2.4; ml, 1.65 X 0.8; m2, 0.8 X 0.75.