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SPHENOPHRYNE - American Museum of Natural History

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100 BULLETIN AMERICAN MUSEUM OF NATURAL HISTORY NO. 253<br />

Fig. 56. Lower surfaces <strong>of</strong> feet and hands <strong>of</strong> Austrochaperina. A. A. rivularis, AMNH A77576. B.<br />

A. macrorhyncha, BPBM 13860. C. A. basipalmata, AMNH A78167. D. A. palmipes, AMNH A81210.<br />

E. A. parkeri, MCZ A89220. F. A. blumi, MZB 3562. Scale bars marked in 1-mm intervals.<br />

The most striking ontogenetic change in<br />

O. stenodactyla is the relative narrowing <strong>of</strong><br />

the head. Head-first burrowing through tightly<br />

packed grass may put a premium on maintaining<br />

a narrow prow.<br />

Austrochaperina derongo has proportions<br />

that I associate with leaf-litter species, in the<br />

midrange <strong>of</strong> the other species and paralleling<br />

the growth changes <strong>of</strong> most others.<br />

Sphenophryne cornuta is notable for its<br />

ontogenetic increase in relative hand size,<br />

foot length, and disc size. These tendencies<br />

must be related to its scansorial habits. The<br />

increase in foot length coupled with a decrease<br />

in tibia length is especially notable,<br />

for in most species these two are directly correlated<br />

both in trend direction and amount.<br />

Liophryne schlaginhaufeni has the longest<br />

legs and feet, and both measurements increase<br />

relatively with growth, in marked contrast<br />

to the other species (but see cornuta,<br />

above). This elongation <strong>of</strong> limb segments<br />

provides an efficient jumping mechanism in<br />

a surface-active species, and the maintenance<br />

<strong>of</strong> relative eye size rather than relative decrease<br />

may be related to surface activity, too.<br />

The increase in the size <strong>of</strong> the small finger<br />

discs is not explicable as a direct adaptation,<br />

but may merely accompany the significant<br />

increase in hand size.<br />

Increase in hand size is presumably a scansorial<br />

adaptation in A. palmipes, although in<br />

this instance the climbing is done on streamassociated<br />

rocks rather than in bushes. The<br />

digital discs are large and either increase<br />

slightly (fingers) or maintain their relative<br />

size (toes).<br />

OSTEOLOGY<br />

A thorough description <strong>of</strong> the osteology is<br />

not possible owing to lack <strong>of</strong> appropriate material<br />

<strong>of</strong> about 40% <strong>of</strong> the species studied. I<br />

have examined cleared-and-stained (bone, or

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