Eocene chelid turtles from Redbank Plains, Southeast Queensland, Australia France de LAPPARENT de BROIN Laboratoire de Paléontologie, UMR 8569 du CNRS, Muséum national d’Histoire naturelle, 8 rue Buffon, F-75231 Paris cedex 05 (France) [email protected] Ralph E. MOLNAR Queensland Museum, P.O. Box 3300, South Brisbane, Queensland (Australia) [email protected] Lapparent de Broin F. de & Molnar R. E. 2001. — Eocene chelid turtles from Redbank Plains, Southeast Queensland, Australia. Geodiversitas 23 (1) : 41-79. ABSTRACT The rich fauna of freshwater turtles from Redbank Plains (Brisbane), Queensland, Eocene (or less probably Palaeocene) includes only Chelidae (Pleurodira). Besides an indeterminate form, five taxa are attributed to two of the three extant groups: three taxa to the Chelodina group, and one or two to the Emydura group, all new, but allowing the erection of only one new spe- KEY WORDS cies, C. alanrixi. They show the degree of differentiation that had already Turtles, Chelidae, occurred here in the evolution of several of the extant lineages of the two Chelodina, groups, consistent with the age of the two groups of genera within the family, Emydura, which has been recorded from the Early Cretaceous of southern Argentina. It Eocene, Australia, reflects the origin of the Chelidae on a single landmass, Gondwanaland, the new species. family representing the southern component of the Pleurodira. GEODIVERSITAS • 2001 • 23 (1) © Publications Scientifiques du Muséum national d’Histoire naturelle, Paris. www.mnhn.fr/publication/ 41 Lapparent de Broin F. de & Molnar R. E. RÉSUMÉ Tortues chélidées de l’Éocène de Redbank Plains, Queensland du sud-est, Australie. La région de Redbank Plains, à côté de Brisbane, Queensland, a livré une importante faune de tortues d’eau douce, attribuée aux seuls Chelidae, Pleurodira, avec deux des trois groupes de genres australiens actuels de la famille. Outre une forme indéterminée, trois taxons sont attribués à Chelodina s.l. et un ou deux à Emydura s.l. Seule l’espèce C. alanrixi est créée, les autres espèces reposant sur du matériel insuffisant quoique nouveau dans MOTS CLÉS le contexte des Chelidae connus. La localité, paléogène, est attribuée à l’Éo- Tortues, Chelidae cène au plus tard. La différentiation déjà nette de plusieurs lignées au sein des Chelodina, deux genres confirme son ancienneté, étant en accord avec l’âge de la famille, Emydura, représentée depuis le Crétacé inférieur du Sud de l’Argentine. Elle reflète Éocène, Australie, l’origine des Chelidae sur un continent unique, le Gondwana, la famille nouvelles espèces. représentant le composant sud des Pleurodira. INTRODUCTION (TABLE 1) still lack formal stratigraphic names and correla- tion is tentative. What Gaffney (1981) termed In 1990, Dr Alan Rix, of the University of “Testudines indeterminant” and then “chelid Queensland, discovered and collected new chelo- material being in press” (Gaffney 1991) comes nian material from the Eocene deposits at from Queensland geological Survey bore num- Redbank Plains, Southeast Queensland. This ber 2, Rockhampton, of the mid to late Eocene included the most complete turtle material yet Rundle Formation (Henstridge & Coshell 1984). collected from this site. A further specimen was This bore is actually just outside Gladstone collected in 1993. Turtles were first mentioned at (Henstridge & Coshell 1984) where abundant Redbank Plains by Jones (1926) who mentioned turtle remains have recently (August, 1999) been “Tortoise remains […] apparently identical with collected from a bonebed in the Kerosene Creek Chelodina insculpta De Vis […]”. Riek (1952) Seam of the Rundle Formation, near Gladstone. figured a fragmentary impression of “skin This material consists of articulated and disarti- of ? turtle” and mentioned “Fragments of the culated shells, isolated limb elements and girdles, carapace and plastron of a turtle […] but they are and at least one mandible. The fossils seem to possibly only those of a recent specimen”. The occupy a single level only a few centimetres thick, turtle material from Redbank Plains was consi- and only sporadic bones or teeth (crocodilian) dered as “Testudines indeterminant” in the first occur outside this level. The collected material synthesis of fossil turtles of Australia (Gaffney suggests at least five individuals per square metre. 1981: fig. 5). Part of the newly collected material A broken shell (QM F14318) from the Condor has been mentioned as “chelid material” and oil shale near Proserpine, between Bowen and figured by Rix (1991). Study of the new material Cape Hillsborough, is still under preparation. in this paper shows that the Redbank Plains This shell pertains to Emydura s.l. sp. (see below) turtles are chelids, belonging to at least five taxa. but its age relative to the Redbank Plains speci- Other possibly Eocene chelid material from mens is unclear. It is given as “lower Tertiary”, Queensland has been found at Rockhampton, with palynological studies giving a range of Proserpine and Cape Hillsborough. The geology “Palaeocene to middle Oligocene” or “Eocene to of this region is still poorly understood and Miocene” (Paine 1972; Green & Bateman 1981) undergoing further description, thus some units depending where in the strata the specimen has 42 GEODIVERSITAS • 2001 • 23 (1) Eocene turtles from Australia TABLE 1. — Oldest chelid or possible chelid records in Palaeogene of Australia. Name First mention Palaeocene Eocene Oligocene Chelidae indet.? Boongerooda Greensand, WA Chelodina alanrixi pro parte Chelodina . Redbank Plains, Q n. sp. a, sp. b, sp. c, insculpta De Vis in Emydura s.l. sp. a and Jones, 1926, pro b?, 1 indeterminate parte “indeterminant” (Gaffney, 1981) Emydura s.l. sp. Chelidae (Gaffney, . 15.5 km SSE Proserpine Q, Cape Hillsborough B. 1991; McNamara, (Palaeocene to middle Oligocene) 1994) Chelidae? “indeterminant” Eight Mile Plains, (not studied) (Gaffney, 1981) Runcorn, near Brisbane, Q, Corinda F. (?Eocene) Chelidae Chelidae Wedge Island at Cape (not studied) (Gaffney, 1991) Hillsborough, Q, Cape Hillsborough B., Wedge Island beds, middle Eocene. Rockhampton, near Gladstone, Q, Rundle Formation (mid- to late Eocene) Chelodina sp. Chelodina insculpta Eocene to Pleistocene: mixed Eocene De Vis, 1897 given of Eight Mile Plains, Q + Plio-Pleistocene as Chelodina sp. in of Darling Downs, SQ, and Warburton River, Gaffney, 1981 SA (lectotype and other figured material from Darling Downs) come from and on the exact location of the speci- et al. 1989; Willis & Molnar 1991). They are men. The Condor oil shale may be part of the believed to be Eocene (Hill & Denmead 1960). Cape Hillsborough Beds or the Plevna beds. De Vis (1897) mentioned other material from Turtle shell fragments (QM L1190), attributed Eight Mile Plains including it in the description to Chelidae, also derive from the “Wedge Island of Chelodina insculpta, along with material from beds”, the lower unit of the Cape Hillsborough the Plio-Pleistocene of the Darling Downs, Beds, of middle Eocene age, at Wedge Island, Queensland, and the Warburton River, South Cape Hillsborough (McNamara 1994). Australia. Unfortunately, he did not specify Other, nearly contemporaneous material from which specimens came from which locality, so it Southeast Queensland, is either very fragmentary is not possible to confirm the presence of or yet unprepared and thus has not been revised. Chelodina at Eight Mile Plains. However, his Fragments of both carapace (UQF 17494- figures (De Vis 1897) show that he did not UQF 17510) and plastron (UQF 24020), some confuse the Emydura and Chelodina groups, the over 1 cm thick, were collected in 1954 from a two main Australian chelid groups, so that the well penetrating the Corinda Formation in the presence of Chelodina in Eight Mile Plains is pos- Brisbane suburb of Eight Mile Plains (Cranfield sible, even if the figured material is only from GEODIVERSITAS • 2001 • 23 (1) 43 Lapparent de Broin F. de & Molnar R. E. Darling Downs (Thomson in prep.) and, particu- Formation of Lightning Ridge, New South larly, the lectotype designed by Gaffney (1981). Wales (Warren 1969b; Molnar 1980; Dettmann Regarding the Warburton River material, Plio- et al. 1992) (casts in the Australian Museum, Pleistocene sediments of the Katipiri Sands, Museum of Victoria and Queensland Museum). which yielded Chelodina insculpta (fide Vickers- Chelycarapookus Warren, 1969, from the Rich & Rich 1993: fig. 259) proceed from the Casterton neighbourhood, Victoria, is definitely margins of this river. Gaffney (1981: fig. 18A) a primitive cryptodire, not a pleurodire contrarily figured as “Chelidae” a specimen attributable to to a previous assessment: a hypothesis still erro- Chelodina, from the Katipiri Formation at Lake neously given (Manning & Kofron 1996) in spite Kanunka, South Australia, Southwest of the of recent work to the contrary (Gaffney 1991) Warburton River in the same area. recently confirmed (Gaffney et al. 1998). Two turtle fragments have been collected (by Observation of the holotype specimen allows a John Long, Western Australian Museum) in the reconstruction of a rounded-oval shell, with ple- Palaeocene Boongerooda Greensand, at Pilbara, siomorphic characters such as anteriorly- and just South of Exmouth Gulf, western Australia. posteriorly-wide intervertebral canal, wide verte- They are indeterminable although probably che- brals (much wider than the costals) and wide lids fragments. One is thick and smooth as are nuchal and cervical; the plastron has short plas- several