SPHENOPHRYNE - American Museum of Natural History

2000 ZWEIFEL: PARTITION OF SPHENOPHRYNE
31
Fig. 16. Comparison of third finger disc
widths in Austrochaperina derongo (circles) and
A. rivularis (squares) from Southern Highlands
Province, Papua New Guinea. For regression data,
see table 3.
A typical note (fig. 80A) begins with three
brief pulses followed by several longer, louder
ones gradually diminishing in duration and intensity.
The note repetition rate is about 1.9/
sec, the dominant frequency being 2650 Hz
(see also Vocalizations).
The frog called from beneath a leaf in a
creekbed adjacent to a small stream beside a
trickle of water (S. Richards, personal commun.).
The voucher specimen is QM J67250;
a copy of the recording is on AMNH Herpetology
tape no. 284. A call by another
specimen (MZB 3564) recorded at the same
locality sounds the same but is masked by
the noise of running water.
COMPARISONS WITH OTHER SPECIES: Austrochaperina
derongo is much like archboldi,
hooglandi, and guttata; only the last, with its
large size, large finger discs, and long legs
(table 2) stands out much from derongo. Color
pattern adequately distinguishes hooglandi,
and most archboldi can be separated by
their greater internarial span and larger eyes.
HABITAT AND HABITS: The association of a
calling individual with water (see above) and
the capture of other specimens in the same
habitat (S. Richards, personal commun.) represent
the only information on the habits and
habitat of this species. Most of the localities
in Papua New Guinea fall in areas mapped
by Paijmans (1975) as ‘‘Medium Crowned
Lowland Hill Forest.’’ The two highest sites
(Wangbin, 1460 m; Mt. Bosavi, 1200 m) are
within Lower Montane Forest zones. Archbold
et al. (1942) described the region where
the Irian Jaya specimens were taken as heavily
mossed rainforest.
DISTRIBUTION: Most locality records for A.
derongo are at moderate to low elevations
along the southern flank of the central dividing
range from just east of the Irian Jaya–
Papua New Guinea border to the Purari River
drainage in Gulf and Simbu provinces; the
Irian Jaya localities are north of the central
ranges and nearly 200 km from the closest
station in Papua New Guinea (fig. 13). The
elevation range is 80–1460 m.
REMARKS: If I am correct in associating
‘‘Sphenophryne sp. B’’ of Mahony et al.
(1992) with derongo (see Karyology), then
this species is unique among the few Austrochaperina
for which there are data in having
the chromosome number 2N of 24 rather
than 26.
There is one known instance of sympatry
between A. derongo and A. rivularis based
on specimens collected by S. Donnellan at
Namosado, Southern Highlands Province,
Papua New Guinea. Two adult male A. rivularis
(AMS R122164, R122165) taken
along with ten A. derongo (AMS R122166–
122169, R122232, R122235–122239) stand
out for their relatively large size: one (SVL
37.7 mm) is larger than any of the 10 derongo
(maximum is a 35.6 mm female) and the
other, at 35.5 mm, is at the upper range of
that series. In all proportions in which derongo
and rivularis differ, the two large
males resemble rivularis rather than derongo.
Figures 14–16 illustrate the greater tibia
length, eye size, and disc width of rivularis
at the site of sympatry.
Variations in size and proportions among
the geographically scattered samples of this
species lead me to suspect that derongo may
be a composite of two or more species. However,
I am unable to subdivide the species to
my satisfaction. More recordings of calls
might resolve the question; the only recording
at present is from the most remote part
of the range.