SPHENOPHRYNE - American Museum of Natural History

78 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 253
Fig. 39. Holotype of Oxydactyla alpestris,
AMNH A76584, SVL 22.7 mm.
file; canthus rostralis rounded, loreal region
sloping, flat; eyes relatively large, corneal
margin barely visible from beneath, interorbital
space about 1.5 width of an upper
eyelid; tympanic annulus indistinct, tympanum
separated from posterior corner of eye
by about its own diameter. Relative lengths
of fingers 3 2 4 1, first well developed,
more than half length of second, tips
narrow, rounded, not flattened, no trace of
terminal groove (fig. 53B); subarticular elevations
virtually nonexistent, inner and middle
metacarpal elevations indistinct, low and
rounded. Toes unwebbed, relative lengths 4
3 5 2 1, first small, less than half
length of second, tips and subarticular elevations
as on hands, inner metatarsal elevation
small, low, rounded, no outer elevation.
Body surfaces smooth dorsally and ventrally;
no skin folds or wartiness.
The dorsal ground color is medium brown.
The side of the head and the eyelids are darker,
almost black, with a few light flecks on
the upper lips. A dark brown streak begins
behind the eye, broadens as it passes above
and behind the tympanum, and fades into the
ground color as it extends diagonally down
the midflank region. The upper edge of this
streak is clearly defined only anteriorly. The
middorsal region shows only a few obscure
hints of darker markings. The upper surfaces
of the limbs are similar but with markings
more obvious, especially on the arms. The
immediate region of the cloacal opening is
pale, surrounded by a black ring. The anterior
surfaces of the thighs are brown with
indistinct lighter spots; the posterior surfaces
have a pale tan ground color mostly obscured
by darker pigment in no definite pattern. The
ground color of the undersides is pale tan.
The border of the lower jaw is dark with a
few light spots. Irregular clumps of dark pigment
on the throat and chest are less dense
on the abdomen but again dominant on the
undersides of the hind legs. The sole is dark
with a few light flecks.
VARIATION IN TYPE SERIES: The largest
specimens are two females from Tomba measuring
27.8 mm SVL. The largest males are
two from Agakamatasa measuring 26.6 and
26.9 mm. Both males and females are unusually
large in comparison with frogs from
other samples, where the largest male is 24.7
mm and females rarely attain 26 mm. Females
mature at about 20 mm. See table 10
for variation in body proportions and table
11 for regression data.
ILLUSTRATIONS: 3rd finger terminal phalanx,
fig. 71B; premaxilla, fig. 63B; sacral
region, fig. 72B; vomer, fig. 65B; hand and
foot, fig. 53B.
CALL: The call has not been described.
COMPARISONS WITH OTHER SPECIES: The
species with which O. alpestris is most likely
to be confused are O. coggeri and O. stenodactyla.
Known localities for alpestris are remote
from those for coggeri, but if the species
should be found together (for example,
in eastern Enga Province), the presence of
grooved, disclike toe tips in coggeri provides
adequate distinction.
The habitat of stenodactyla appears to be
generally at higher elevations than that of alpestris,
but the two species evidently occur
together on the Sepik-Wahgi Dividing
Range. Although there is overlap between
the two species in ranges of all the standard
ratios (table 10), the means are well separated,
and combining two ratios (TL/SVL and
EY/SVL) achieves a nearly complete division
(fig. 46). Specimens of stenodactyla
from the sympatric sample fall within the
area of the stenodactyla sample in figure 22.
HABITAT AND HABITS: Tyler (1963), in re-