Historical Papers
Glaessner, M.F. (1942). The occurrence of the New Guinea turtle (Carettochelys) in the Miocene of Papua. Rec. Aust. Mus. 21:106-109. ¹
Although we have still no definitive knowledge of the aniquity of Carettochelys in New Guinea, it is an interesting fact that the genus existed there in Miocene times. Discussing the history of the family Carettochelyidae for which he assumes an Asiatic origin Hummel8 states: "Carettochelys exists in New Guinea probably as a relic of the Upper Mesozoic, like the Australian marsupials, the known species of Anosteira occur in the Eocene. They lived at the time when New Guinea and Asia were already disconnected. That Carettochelys did not migrate to New Guinea in Cainozoic times like Pelochelys is contended by the fact that Carettochelys is restricted to New Guinea while is widely distributed on the Asiatic continent."
The latter contention gains further weight by our new discovery, as it is unlikely, in the present writers opinion, that any part of the island of New Guinea was land connected with or close to either Asia or Australia at any time between the Eocene and the late Pliocene or Pleistocene. The regressive phase at the boundary between Cretaceous and Tertiary is the most likely time of immigration for a non-marine species existing in New Guinea in Miocene time.
Ecology of Carettochelys - Carettochelys is a typical river-turtle, and does not appear to differ in its habits from the Trionychidae. Walther considers migration along the coast from one river to another as possible, and Hummel,9 speaking of the Trionychia in general, remarks: "The sea does not form an impassible barrier for the Trionychia. Repeatedly, as for example in the harbour of Wladiwostok and on the coast of West Africa, living Trionyx have been observed in the sea. Trionychia can also live in lagoons . . . . It is likely, however, that Trionyx makes such excursions into the sea only rarely and probably not altogether voluntarily . . . . It cannot be definitely decided wether the wide range of Trionyx throughout the islands of the Western Pacific and Indonesia has any connection with the ability of these animals to swim across the arms of the sea . . . ." The present writer,10 having examined the occurance of fossil turtles in the Miocene of central Europe, came to the conclusion that it has to be assumed that Trionyx vindobonensis had its regular habitat in the littoral swamps or brackish lagoons of the Sarmalian sea.
It is perfectly clear that the occurance of the single detached bone of Carettochelys found in the marine Miocene of Papua does not indicate that this turtle lived exactly at the place and in the environment in which its remains have been buried and found. The beds which contain marine Foraminifera, corals, and mollusca, consist of interbedded course and fine terrigenous rich in comminuted lignitic plant remains. Current action during deposition is evident in many places. The currents must have brought the bone from the swampy shore or brackish lagoon, possibly connected with a river estuary which was the probable habitat of the fossil Carettochelys.
1. Published by permision of the Directors, Australasian Petroleum Company, Proprietry Limited, Melbourne, Victoria.
2. Ramsay.-Proc. Linn. Soc. N.S.W. (2). 1. 1886, p. 158. Waite.-Rec. Australian Mus., vi, 1905, p. 110. Ogilby.-Proc. Royal Soc. Queensland, xix, 1905, p. 1. Longman.-Mem. Queensland Mus. II, 1913. p. 39. de Rooij.-The Reptiles of the Indo-Australian Archaepelago. Part I Lacertilia. Chelonin, Emydosuchia. Leiden, 1915. Walther.-Novae Guinea, xiii, 1922. p. 607.
3. Walther.-loc.cit, p. 616.
4. Hummel.-Geologische und Palaeontologische Abhandlungden (n.s.) xvi, 1929. fig 11a.
5. Ramsay.-loc.cit. Waite.-loc.cit.
6. Longman.-loc.cit.
7. de Rooij.-loc.cit. Walther.-loc.cit.
8. Hummel.-loc.cit. p. 94. The translation is mine - M.F.G.
9. Hummel.-loc.cit. p. 72. The translation is mine - M.F.G.
10. Glaessner.-Neues Jahrbuch für Minerologie. Geologie und Paläontologie. Bellage. ixix, B, p. 374.