SPHENOPHRYNE - American Museum of Natural History
SPHENOPHRYNE - American Museum of Natural History
SPHENOPHRYNE - American Museum of Natural History
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2000 ZWEIFEL: PARTITION OF <strong>SPHENOPHRYNE</strong><br />
73<br />
ident in living specimens. The colors in life<br />
are not greatly different from those <strong>of</strong> the<br />
preserved specimens except for their relatively<br />
greater brightness.<br />
HABITAT AND HABITS: The habitat <strong>of</strong> Liophryne<br />
similis at Myola Guest House is<br />
heavily mossed forest (mapped by Paijmans,<br />
1975, as Lower Montane Forest) bordering a<br />
grassy meadow (see Zweifel and Parker,<br />
1989: fig. 7). We found most <strong>of</strong> our specimens<br />
by day beneath surface cover. One discovered<br />
at night was active on the surface <strong>of</strong><br />
the leaf litter (see also under Call, below).<br />
A male L. similis <strong>of</strong> 29 mm SVL (AMNH<br />
A130565, fig. 11) was associated with a<br />
group <strong>of</strong> 24 eggs (AMNH 130565) with capsular<br />
diameters <strong>of</strong> 6–7 mm and connected by<br />
peduncles <strong>of</strong> about the same length. Judged<br />
from the size at maturity <strong>of</strong> L. rhododactyla,<br />
a similis <strong>of</strong> this size would not be mature, so<br />
the association probably was fortuitous.<br />
However, the large clutch size and relatively<br />
large size <strong>of</strong> the eggs favors the identification<br />
<strong>of</strong> the eggs as those <strong>of</strong> L. similis, unless there<br />
is a large terrestrial microhylid present that<br />
we did not find.<br />
ILLUSTRATIONS: Hand and foot, fig. 54C.<br />
CALL: I recorded the call at the type locality<br />
in August 1987 (AMNH Herpetology<br />
tape reels 252 and 253). It is a series <strong>of</strong> 7–<br />
10 clear, moderately loud piping notes, each<br />
about 0.06 sec long delivered over the space<br />
<strong>of</strong> 0.75– 1.24 sec (fig. 77B). Notes are unpulsed<br />
and frequency is modulated, with an<br />
initial rapid rise <strong>of</strong> the dominant frequency<br />
from about 540–600 Hz to a peak <strong>of</strong> 680–<br />
720 Hz and then a lesser, slower descent.<br />
Four calls <strong>of</strong> the holotype recorded in the<br />
field at an air temperature <strong>of</strong> 12.8C averaged<br />
1.20 sec long (1.09–1.24) with a rate <strong>of</strong> 7.65<br />
(7.6–7.7) notes per sec. Intervals <strong>of</strong> almost<br />
exactly 1 min separated the four calls. Another<br />
recording involved several frogs in a<br />
collecting bag, at least two <strong>of</strong> which called<br />
at 15.5C. The anticipated correlations with<br />
higher temperature are confirmed in the data<br />
for these eight calls: shorter call length<br />
(mean 0.98, range 0.75–1.17 sec) and faster<br />
note repetition rate (mean 8.5, range 8.2–8.8<br />
notes per sec). Only L. similis were in the<br />
bag, so there is no question <strong>of</strong> the association<br />
<strong>of</strong> species and call.<br />
The holotype was calling from among the<br />
prop roots <strong>of</strong> a pandanus at about 2300 hours<br />
following an afternoon rain. It was on the<br />
surface, not hidden in the litter.<br />
COMPARISONS WITH OTHER SPECIES: Inall<br />
but the call and morphological features associated<br />
with vocalization, this species appears<br />
to be identical to L. rhododactyla. This<br />
is emphasized by the extreme closeness<br />
(identical means in two instances) <strong>of</strong> the various<br />
morphological ratios <strong>of</strong> adults (table 6),<br />
and by the similarity <strong>of</strong> ontogenetic trends<br />
revealed by the regressions (table 7). In addition<br />
to the clearcut character <strong>of</strong> the presence<br />
or absence <strong>of</strong> vocal sac and slits, there<br />
may be a specific difference in the size <strong>of</strong> the<br />
tympanum <strong>of</strong> adults. Regression lines for<br />
tympanum diameter relative to snout–vent<br />
length diverge notably, with similis having<br />
the larger tympanum. There is broad overlap<br />
in tympanum size, however, and the sample<br />
is not adequate for determining a possible influence<br />
<strong>of</strong> sexual dimorphism.<br />
Juvenile L. similis may be confused with<br />
the much smaller, sympatric Austrochaperina<br />
brevipes, as is discussed in the account <strong>of</strong><br />
that species.<br />
DISTRIBUTION: Known only from the type<br />
locality (fig. 34). See Holotype and Paratypes<br />
for details.<br />
REMARKS: Evidence provided by the calls<br />
strongly indicates that L. rhododactyla and<br />
L. similis are different species, their close<br />
morphological similarity notwithstanding.<br />
Differences between the calls may be explained<br />
by (1) functionally different calls<br />
(e.g., territorial and mate-attracting) that<br />
were recorded for the same species, or (2)<br />
the samples represent sibling species. With<br />
respect to the first possibility, I heard the sort<br />
<strong>of</strong> call recorded at Myola on several nights<br />
and did not hear the other call there. Allen<br />
Allison has had much field experience with<br />
L. rhododactyla, and reported to me (personal<br />
commun.), ‘‘I have never heard anything<br />
else from this species and have heard this<br />
species calling practically every time that I<br />
visited Bulldog Road.’’ He listened to a playback<br />
<strong>of</strong> the similis call and assured me that<br />
he had not heard that call before. This information,<br />
coupled with the single morphological<br />
difference (vocal slits and sac present in<br />
rhododactyla, absent in similis) leads me to