SPHENOPHRYNE - American Museum of Natural History

54 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 253
note above on a recorded individual, nothing
else is known about the habits of this species.
DISTRIBUTION: The known localities are in
or on the fringe of the central mountainous
region of western Papua New Guinea in
Western, West Sepik, East Sepik, and Southern
Highlands Provinces (fig. 29). The species
undoubtedly occurs in eastern Irian Jaya,
as the type locality is only 22 km from the
border. The known range in elevation is
about 600 to 1600 m. For locality records
and specimens examined, see above under
Holotype, Paratypes, and Referred Specimens.
REMARKS: The question of whether A. rivularis
is a species distinct from A. derongo
is answered by their distinction in sympatry
in Southern Highlands Province of Papua
New Guinea as well as by differences in advertisement
calls. See the account of A. derongo
for details of the sympatric locality.
Another question is whether rivularis includes
more than one species. The larger
body size seen in the Mt. Hunstein sample is
suggestive, but there are no other morphological
characters sufficiently trenchant to
mark species lines. Also, geographic variation
in body size is seen in the related species
derongo and palmipes. Information on advertisement
calls might be helpful in resolving
the question if more populations can be
sampled.
Austrochaperina yelaensis, new species
HOLOTYPE: AMNH A135406, collected by
R. F. Peterson on the Fifth Archbold Expedition
between October 12 and 20, 1956, at
an elevation of 700 m on the south slopes of
Mt. Rossel, Yela ( Rossel) Island, Milne
Bay Province, Papua New Guinea.
PARATYPES: There are no paratypes.
ETYMOLOGY: The Latin adjectival suffix
-ensis (origin) reflects the provenance of the
holotype, the name of which has been
changed from Rossel Island to Yela Island.
DIAGNOSIS: A small Austrochaperina—
SVL 20.5 mm in the single specimen, a female
at or close to adulthood—with moderately
well-developed digital discs, an obscurely
mottled dorsal color pattern, small
pale spots prominent on the face and side of
body, and mottled abdomen.
DESCRIPTION OF HOLOTYPE: A female, at or
close to maturity (ova 1.5 mm in diameter),
with the following measurements and proportions:
SVL 20.5, HW 7.9, TL 9.3, EY 2.8,
EN 1.6, IN 2.3, HD 4.2, FT 9.3, disc of third
finger 0.6 (penultimate phalanx 0.4), disc of
fourth toe 0.8 (0.4); HW/SVL 0.385, TL/
SVL 0.454, EY/SVL 0.127, EN/SVL 0.078,
IN/SVL 0.112, EN/IN 0.696, HD/SVL
0.205, FT/SVL 0.454, FD/SVL 0.029, TD/
SVL 0.039.
Head scarcely narrower than body, snout
obtusely rounded, barely projecting in profile;
loreal region sloping and flat, canthus
rostralis rounded; nostrils barely visible from
above, nostril closer to tip of snout than to
eye. Eyes relatively large, visible from beneath,
interorbital distance about 80% of an
eyelid width; tympanum hidden. Relative
lengths of fingers 3 4 2 1, first finger
well developed, about half length of second,
all fingers with small, grooved terminal
discs; subarticular and inner metacarpal elevations
low and rounded (fig. 57A). Toes unwebbed,
relative lengths 4 3 5 2
1, all with grooved terminal discs, those of
third and fourth toes about twice width of
penultimate phalanges; subarticular and inner
metatarsal elevations low but discrete, no
outer metatarsal elevation (fig. 57A). Skin
smooth above and below, a faint trace of a
postocular-supratympanic fold.
The dorsum is brown and faintly mottled.
Small white spots are prominent atop the
snout, on the upper lips and sides of the face
through the tympanic region, and along the
side of the body. The upper surfaces of the
hands, arms, and front legs and hind legs are
similarly spotted. The throat and chest are
brown with white spots, the abdomen and
undersides of hind legs mottled. The groin
and anterior surface of the thigh are brown
with irregular, small light marks; the posterior
surface is similar but with slightly larger
markings.
VARIATION IN TYPE SERIES: There is only
the single specimen, so the extent and nature
of variation are unknown. That the specimen
is mature at less than 21 mm SVL indicates
that this is one of the smallest species of Austrochaperina.
ILLUSTRATIONS: Hand and foot, fig. 57A.