Australian frogs of the family Microhylidae. Bulletin of the AMNH ; v. 182, article 3
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Date
1985
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[New York] : American Museum of Natural History
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Abstract
"Study of abundant new material leads to the recognition of 16 species in the Australian microhylid fauna, all but one endemic, in contrast to 8 previously known. One of 5 Sphenophryne and 6 of 11 Cophixalus are described as new species. Differences between advertisement calls are crucial to distinguishing between members of two pairs of sibling species and are important in diagnosing other species. One species of Sphenophryne inhabiting northern Cape York Peninsula and southern New Guinea is the only microhylid common to both areas. It and its sibling in the Northern Territory inhabit regions with prolonged dry seasons, in contrast to the three remaining species of Sphenophryne which are confined to rainforest in tropical northeast Queensland. One species of Cophixalus occurs in a boulder-jumble area a few kilometers outside the rainforest boundary, whereas the other ten apparently live only in rainforest. Most species of Cophixalus are known only from one or two localities but one -- C. ornatus -- has an extensive range, more than 300 km from north to south. The species of Sphenophryne inhabit leaf litter. Only one Cophixalus is principally a ground dweller, the remaining species being more or less scansorial. Like other genyophrynine microhylids, the Australian species presumably all lay large eggs in sheltered, terrestrial situations. An adult frog, male in the few verified instances, accompanies the eggs, which undergo direct development, producing fully formed froglets. The five species of Sphenophryne include two sibling pairs, with all five species being so similar morphologically that they were taxonomically confused in the earlier literature. The Australian species share no characters clearly apomorphic for the genus, and little can be said as to relationships with the more diverse New Guinean Sphenophryne. Similar mating call structure among the Australian Sphenophryne suggests that they form a monophyletic group, but the possibility remains that the calls are primitive and not indicative of close relationship. Australian Cophixalus are morphologically much more diverse than Sphenophryne, though similarly tied together by commonality of elements in the advertisement calls (quite different from those of Sphenophryne) that implies monophyly. Interspecific comparisons of body proportions by use of regression lines reveal many similarities and differences among species, but placement of particular characters on a primitive-derived axis is far from satisfactory. Furthermore, parallel development of presumably apomorphic traits seems to have been common. As a result, the relationships diagrammed are even more subjective than usual. Previous assessments of the Australian microhylids as a slightly differentiated group derived by dispersal from New Guinea are rejected. Paleoclimatic evidence that tropical rainforest habitat suitable for microhylids has been present in northern Australia since well before the Pleistocene, the accessibility of Australia-New Guinea to Southeast Asia since the Miocene collision of plates, and the high degree of endemicity in Australia argue for a long history in situ. Whether the Australian microhylids derive directly from a Gondwanan source, originate from Gondwana indirectly by way of Indian continental drift and subsequent dispersal through Southeast Asia to Australia, or are not of Gondwanan origin at all remains unresolved"--P. 267.
Description
p. 267-388 : ill., maps ; 26 cm.
Includes bibliographical references (p. 385-388).
Includes bibliographical references (p. 385-388).
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