SPHENOPHRYNE - American Museum of Natural History

74 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 253
conclude that two species should be recognized.
The type locality of Liophryne rhododactyla,
Mt. Victoria, is much closer to Myola
Guest House (38 km) than to the region
southeast of Wau (about 190 km) where recordings
of rhododactyla were made. Presumably
at least three disjunct populations
are involved (fig. 34)—two of rhododactyla
and one of similis. On the basis of proximity,
one might expect the frogs at Mt. Victoria
and Myola to represent the same species,
with the disjunct northern population near
Wau requiring a new name. Countering this
interpretation is the morphological evidence
of the vocal sac apparatus, intimately associated
with the difference in calls. Verification
of the call of rhododactyla at the type
locality is much desired.
A striking, parallel geographic situation
exists in the microhylid genus Aphantophryne
(Zweifel and Parker, 1989). This genus
has the same basic distribution as L. rhododactyla
and L. similis—high elevations near
Wau and in the Owen Stanley Mountains.
Aphantophryne pansa occurs with L. rhododactyla
near Wau and both inhabit high
elevations in the central Owen Stanley
Range. At Myola Guest House, Aphantophryne
sabini, a sibling of A. pansa distinguished
mainly by its call, occurs with L.
similis.
Genus Oxydactyla van Kampen
Oxydactyla van Kampen, 1913: 464. Type
species (by monotypy) Oxydactyla brevicrus
van Kampen, 1913: 465.
Sphenophryne: Parker, 1934: 152 (Oxydactyla
referred to synonymy of Sphenophryne).
CONTENT: Five species: Oxydactyla alpestris,
new species; Oxydactyla brevicrus van
Kampen; Oxydactyla coggeri, new species;
Oxydactyla crassa (Zweifel); Oxydactyla
stenodactyla, new species.
DIAGNOSIS: A genus of genyophrynine microhylid
frogs (sensu Zweifel, 1971, and
Burton, 1986) with the following combination
of morphological characters: clavicles
long and slender, reaching from scapula almost
to midline of pectoral girdle; legs short,
maximum TL/SVL 0.395; tips of fingers
narrow and rounded, or, if slightly flattened,
not disclike and with terminal grooves lacking
or only weakly indicated on fingers 2–4.
MORPHOLOGY: These are small, short-legged
frogs, with a maximum known SVL of
32 mm and mature males as small as 19 mm
SVL in one species. Mean TL/SVL ratios
range from 0.294 to 0.366, a range that excludes
almost all other species with the primitive
pectoral girdle. The situation with respect
to small foot size is similar: mean FT/
SVL 0.338–0.399, with just one other species
having a mean in this range. The hands
are small, with the range of means HD/SVL
(0.199–0.213) falling within the lower 30%
of the total range for all genyophrynine species
with the primitive pectoral girdle. The
fingertips show little or no trace of the expanded,
flattened discs with prominent terminal
grooves seen in other species with the
primitive pectoral girdle. The species pair alpestris
stenodactyla has the most derived
condition, with no trace of fleshy expansion
or grooving (fig. 49) and with the underlying
terminal phalanges having slightly constricted
tips much narrower than the base of the
bone (fig. 71A, B). In other species of Oxydactyla
the tips may be slightly flattened but
with no more than a faint terminal groove on
fingers 2–4, and the terminal phalanges
(where known) are bluntly T-shaped with the
tip not or scarcely wider than the base (fig.
71C, D). The toe tips of alpestris and stenodactyla
resemble those of the fingers externally,
although the terminal phalanges have
slightly more of a T shape. Toe tips in the
other Oxydactyla are less extremely modified
from the common slightly expanded disc
with T-shaped phalanges. The tympanic annulus
is not well defined externally, but the
ear is not notably reduced in size. Mean eye
size is small to moderate (EY/SVL 0.093–
0.117). These frogs have the morphology
commonly associated with cryptic, terrestrial
habits, which fits well with what is known of
their ecology. See table 10 for body proportions
of the species and table 11 for regression
statistics.
DISTRIBUTION: The genus is montane and
confined to high elevations, with records
ranging from 1800 to 4000 m. One species
is in the central ranges of Irian Jaya, three in
the highlands of Papua New Guinea, and one