Online Encyclopedia


Online Encyclopedia
Originally appearing in Volume V23, Page 173 of the 1911 Encyclopedia Britannica.
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AUSTRALIAN REGION.—Of crocodiles only. C. johnstoni in N. Australia and Queensland; C. porosus on the N. coast, and occur-ring on various Pacific islands, as far E. as the Fiji Islands. Tortoises are represented only by the pleurodirous Chelydidae, e.g. Chelodina; they are absent in Tasmania and on the Pacific islands. New Guinea possesses the aquatic Carettochelys, sole type of a family. The bulk of the Lacertilian fauna is composed of skinks, geckos, agamoids and Varanidae, with the addition of a small family which is peculiar to the region, the Pygopodidae. A peculiar type, Dibamus, inhabits the borderlands, namely, New Guinea, the Moluccas, Celebes and the Nicobar Islands; and, finally, a single iguanoid, Brachylophus, is common in the Fiji Islands; how it came there, or how it survived its severance from the American stock, is a mystery. The skinks are in this region more highly developed and more specialized than in any other part of the world; they exceed in numbers the geckos, which generally accompany the skinks in their range over the smaller islands of the Pacific; in these islands members of these two families represent the whole of the Lacertilian fauna. The Australian agamoids are chiefly peculiar and partly much differentiated forms (e.g. Moloch and Chlamydosaurus), but some have distinct affinities to, or are even identical with, Indian genera. The Varanidae are also closely allied to Indian species. Of snakes, amounting to about one hundred species only, we note about one dozen Typhlopidae, and of Pythoninae simply Python, and the Boine Enygrus on the islands from New Guinea to Fiji. There are but surprisingly few innocuous colubrine snakes, scarcely a dozen, and all belonging to Indian genera. The bulk of the snakes belong to the poisonous Elapinae, all of genera peculiar to the region, e.g. Acanthophis, Pseudechis, Notechis. Such a preponderance of poisonous over harmless snakes is found nowhere else in the world. Tasmania is tenanted by poisonous snakes only. In Australia we meet, therefore, with the interesting fact that, whilst it is closely allied to S. America, but totally distinct from India by its Chelonians, its lizards and colubrine snakes connect it with this latter region. With regard to the other Ophidians, they have their nearest allies partly in India, partly in Madagascar, partly in S. America; and the character of the Australian snake fauna consists chiefly in its peculiar composition, differing thereby more from the other equatorial regions than those do among them-selves. Wallace's line marks the boundary between India and Australia only as far as Chelonians are concerned, but it is quite effaced by the distribution of lizards and snakes. Thus in New Guinea lizards of the Indian region are mixed with Pygopodidae, and an island as far E. as Timorlaut is inhabited by snakes, some of which are peculiarly Indian, whilst the others are as decidedly Australian. The islands N. of New Guinea and of Melanesia are not yet occupied by the Ophidian type, and only species of Enygrus have penetrated eastwards as far as the Low Archipelago, whilst the Fiji Islands and the larger islands of Melanesia have sufficiently long been raised above the level of the sea to develop quite peculiar genera of snakes.

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