Elsevier Editorial System(tm) for Gondwana Research Manuscript Draft
Manuscript Number: GR-D-14-00205R1
Title: Thalassodromeus sebesensis - a new name for an old turtle. Comment on "Thalassodromeus sebesensis, an out of place and out of time Gondwanan tapejarid pterosaur", Grellet-Tinner and Codrea (online July 2014 DOI 10.1016/j.gr.2014.06.002)
Article Type: Discussion
Corresponding Author: Dr. Gareth Dyke,
Corresponding Author's Institution:
First Author: Gareth Dyke
Order of Authors: Gareth Dyke; Mátyás Vremir; Stephen Brusatte; Gabe Bever; Eric Buffetaut; Sandra Chapman; Zoltán Csiki-Sava; Alexander Kellner; Elizabeth Martin; Darren Naish; Mark Norell; Attila Osi; Felipe Pinheiro; Edina Prondvai; Márton Rabi; Taissa Rodrigues; Lorna Steel; Haiyan Tong; Bruno Vila Nova; Mark Witton
Cover Letter
9th JUly 2014
Re: Multi-authored Comment on Grellet-Tinner and Codrea (2014)
Dear Editors, Prof Santosh: Following our extensive correspondence over email, please find our submitted Comment on the recent Grellet-Tinner and Codrea (2014) article in GR: "Thalassodromeus sebesensis, an out of place and out of time Gondwanan tapejarid pterosaur", Grellet-Tinner and Codrea (online July 2014 DOI 10.1016/j.gr.2014.06.002)
I did not see the Comment and Reply format for submission to the Journal (on this site) so have used the GR Letter submission format; I hope that is ok for review.
Yours sincerely
Gareth Dyke Senior Lecturer, Vertebrate Palaeontology Ocean and Earth Science National Oceanography Centre, Southampton University of Southampton Southampton SO14 3ZH UK Direct tel: +44 (0)23 8023110 email: [email protected]
The University of Southampton is a hosting partner of the National Oceanography Centre *Manuscript Click here to view linked References
Thalassodromeus sebesensis - a new name for an old turtle. Comment on 1 2 “Thalassodromeus sebesensis, an out of place and out of time Gondwanan tapejarid 3 4 5 pterosaur”, Grellet-Tinner and Codrea (online July 2014 DOI 10.1016/j.gr.2014.06.002) 6 7 8 9 a,b* c d e,j f 10 Gareth Dyke , Mátyás Vremir , Stephen L. Brusatte , G. S. Bever , Eric Buffetaut , Sandra 11 12 Chapmang, Zoltán Csiki-Savah, Alexander Kellneri, Elizabeth Martina, Darren Naisha, Mark 13 14 j k l k m n 15 Norell , Attila Ősi , Felipe L. Pinheiro , Edina Prondvai , Márton Rabi , Taissa Rodrigues , 16 g o p q 17 Lorna Steel , Haiyan Tong , Bruno C. Vila Nova , Mark Witton 18 19 20 21 a 22 Ocean and Earth Science, University of Southampton, National Oceanography Centre, 23 24 Southampton, University of Southampton, Southampton SO14 3ZH, UK 25 26 b 27 MTA-DE “Lendület” Behavioural Ecology Research Group, Department of Evolutionary 28 29 Zoology and Human Biology, University of Debrecen, Egyetem tér 1., H–4032 Debrecen, 30 31 Hungary 32 33 c 34 Department of Natural Sciences, Transylvanian Museum Society, Cluj-Napoca, Romania 35 36 dSchool of GeoSciences, University of Edinburgh, Grant Institute, King‟s Buildings, West 37 38 39 Mains Road, Edinburgh EH9 3JW, UK 40 41 eDepartment of Anatomy, New York Institute of Anatomy College of Osteopathic Medicine, 42 43 44 Old Westbury, NY 11568, USA 45 f 46 Laboratoire de Géologie de l'Ecole Normale Supérieure, 24 rue Lhomond, 75231 Paris 47 48 Cedex 05, France 49 50 g 51 Department of Earth Sciences, Natural History Museum, Cromwell Road, London, SW7 52 53 5BD, UK 54 55 h 56 Laboratory of Paleontology, Faculty of Geology and Geophysics, University of Bucharest, 1 N. 57 58 Bălcescu Blvd., 010041 Bucharest, Romania 59 60 61 62 63 64 1 65 iLaboratory of Systematics and Taphonomy of Fossil Vertebrates, Department of Geology 1 2 and Paleontology, Museu Nacional/Universidade Federal do Rio de Janeiro, Quinta da Boa 3 4 5 Vista s/n, São Cristóvão, CEP 20940-040, Rio de Janeiro, RJ, Brazil 6 7 jDivision of Paleontology, American Museum of Natural History, Central Park West at 79th Street, 8 9 10 New York, NY, 10024 USA 11 12 kMTA-ELTE Lendület Dinosaur Research Group, Budapest, Pázmány Péter sétány 1/c, 1117, 13 14 15 Hungary 16 l 17 Laboratório de Paleobiologia, Universidade Federal do Pampa, Av. Antônio Trilha, 1847, 18 19 São Gabriel, RS, Brazil 20 21 m 22 Institut für Geowissenschaften, University of Tübingen, Hölderlinstraße 12, 72074, 23 24 Tübingen, Germany 25 26 27 n 28 Department of Biology, Agrarian Sciences Center, Universidade Federal do Espírito Santo, 29 30 Caixa Postal 16, CEP 29500-000, Alegre, ES, Brazil 31 32 33 oPalaeontological Research and Education Centre, Mahasarakham University, Kantarawichai, 34 35 36 Mahasarakham 44150, Thailand 37 38 39 pLaboratório de Paleontologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, 40 41 42 Universidade de São Paulo, Av Bandeirantes 3900, CEP 14040-901, Ribeirão Preto, SP, 43 44 Brazil 45 46 47 qSchool of Earth and Environmental Sciences, University of Portsmouth, Burnaby Building, 48 49 50 Burnaby Road, Portsmouth, PO1 3QL, UK 51 52 53 *Corresponding author, email: [email protected] 54 55 56 57 58 59 60 61 62 63 64 2 65 1. Introduction 1 2 In a recent Gondwana Research article Grellet-Tinner and Codrea (2014) (hereafter 3 4 5 “GTC”) describe a single bone (UBB ODA-28, collections of Babeş-Bolyai University, Cluj 6 7 Napoca, Romania) from the Upper Cretaceous Şard Formation (= middle section of the Sebeş 8 9 10 Formation) (Transylvanian Basin, Romania) as a pterosaur premaxillary cranial crest. They 11 12 assign this fossil to a new species of small pterosaur, Thalassodromeus sebesensis (a name 13 14 15 first coined in a conference abstract published in 2013; Grellet-Tinner et al., 2013). GTC 16 17 build a taxonomic argument on the basis of this single incomplete specimen that posits the 18 19 presence of a major group of pterosaurs hitherto entirely restricted to the Early Cretaceous of 20 21 22 South America - thalassodromines (Kellner and Campos, 2007) or thalassodromids (Witton, 23 24 2009) - in the European Late Cretaceous. GTC note that “this important discovery doubles 25 26 27 the thalassadromine fossil record and demonstrates a 42 million years temporal displacement 28 29 between the Romanian species and its older Aptian Gondwanan congener Thalassodromeus 30 31 32 sethi”. If GTC are correct, this new fossil represents a remarkably unexpected and potentially 33 34 very important discovery that could rewrite aspects of pterosaur evolutionary history. 35 36 We have assembled a large international team who disagree with the arguments 37 38 39 presented by GTC. As we demonstrate, the fossil fragment they describe is misidentified; it 40 41 is, firstly, not from a pterosaur but is clearly a piece of the shell of the turtle Kallokibotion 42 43 44 Nopcsa, 1923 and, secondly, is therefore not the groundbreaking discovery of an 45 46 „anachronistic‟ Gondwanan pterosaur in Europe as claimed. Because ODA-28 is not a 47 48 49 pterosaur, yet alone a Thalassodromeus, GTC‟s conclusions on migration routes and insular 50 51 dwarfism are also unsupported. 52 53 54 55 56 2. ODA-28 is not a pterosaur head crest or even part of a pterosaur 57 58 59 60 61 62 63 64 3 65 The similarity of ODA-28 to pterosaur fossils is superficial; the GTC specimen 1 2 possesses no apomorphies or other characteristic features of Pterosauria. Most importantly, 3 4 5 the thickness, cross sectional morphology, and asymmetry of the specimen demonstrate that it 6 7 is not a pterosaur head crest, or a pterosaur bone of any kind. Pterodactyloid bones, including 8 9 10 the head crests and bones of thalassodromines, are characterised by millimetre-thick bone 11 12 walls separated by networks of fine trabeculae (e.g. de Ricqlès et al., 2000, Sayão, 2003, 13 14 15 Steel et al., 2005, Fig, 4; Steel, 2008). In contrast, broken margins of ODA-28 exhibit two 16 17 layers of compact bone separated by a diploë (a a spongy layer), not thin bone separated by 18 19 trabeculae. In ODA-28 the two compact bone layers are asymmetrical, with one layer thicker 20 21 22 than the other. Pterosaur cranial crests, on the other hand, are medially positioned structures 23 24 with symmetrical bone thickness on the left and right sides (Kellner and Campos, 2002; 25 26 27 Martill and Naish, 2006). 28 29 The anatomy of ODA-28 is distinctly different from all known pterosaur head crests. 30 31 32 The „fossae‟ meant to link ODA-28 to Thalassodromeus sethi are morphologically and 33 34 topographically unlike the fenestrae at the base of Thalassodromeus headcrests, which are 35 36 elongate, located posterior to the orbit (and thus to the nasoantorbital fenestra), and 37 38 39 perforated (Kellner and Campos, 2007, Fig. 10). Alleged anatomical features of the 40 41 specimen, including a nasal process, anterodorsal margin of the nasoantorbital fenestra, and 42 43 44 „finger-like projections‟ from alleged crest margins, are morphologically irreconcilable with 45 46 thalassodromines and other pterosaur crania and are, as we will demonstrate below, 47 48 49 consistent with identification of this material as part of a turtle. 50 51 Even if ODA-28 unexpectedly represents a histologically and morphologically bizarre 52 53 pterosaurian bone, it does not exhibit any clear similarities with the pterosaur 54 55 56 Thalassodromeus. For example, the irregular „ventral‟ margin of ODA-28 compares poorly 57 58 with the smooth, sweeping nasoantorbital margin of Thalassodromeus and other 59 60 61 62 63 64 4 65 monofenestratan pterosaurs (Martill and Naish, 2006, Kellner and Campos, 2007). The flat, 1 2 unremarkable „nasal process‟ of ODA-28 is entirely unlike the tapering process of the nasal 3 4 5 of Thalassodromeus and related pterosaurs. The “finger-like projections” of ODA-28 are not 6 7 seen in Thalassodromeus, and in fact have no precedent on any pterosaur cranial crest, even 8 9 10 among the fine, fibrous crest structures which anchored soft-tissues in many pterosaur species 11 12 (e.g. Frey et al., 2003). 13 14 15 16 17 3. ODA-28 is a piece of fossil turtle shell 18 19 In the Supplementary Text accompanying their paper GTC discussed (and rejected) the 20 21 22 possibility that ODA-28 might be part of a turtle. This is the correct interpretation of this 23 24 fragmentary specimen; ODA-28 is a partial posterior plastral lobe of the turtle Kallokibotion 25 26 27 Nopcsa, 1923. Specifically, this specimen is an articulated left hypoplastron and xiphiplastron 28 29 with a damaged inguinal buttress and a partially broken anal notch, preserved in a sandstone 30 31 32 concretion and exposed in dorsal/internal view (Fig.1). Our reinterpretation is based on 33 34 several morphological characters discussed below and comparison with the posterior plastral 35 36 elements of other Kallokibotion specimens, including the designated type material (Nopcsa, 37 38 39 1923b; Gaffney and Meylan, 1992). 40 41 The hypoplastron is trapezoidal and exhibits a well-developed sutural margin on its 42 43 44 cranial edge (the mesoplastron/hyoplastron-hypoplastral contact), as in Kallokibotion. Based 45 46 on the diverging angle of the meso-hypoplastral suture, we suspect that originally the two 47 48 49 mesoplastra were not in contact axially (as in K. bajazidi) (so there is also hyoplastron- 50 51 hypoplastron contact medially). What GTC identified as “finger-like projections” represent 52 53 incomplete ossification of the inter-hypoplastral sutures, as is characteristic of juvenile and 54 55 56 sub-adult individuals. The inguinal buttress (where the maximum bone thickness is reached) 57 58 59 60 61 62 63 64 5 65 is distally incomplete, and extends laterally from the long axis at a right angle, forming what 1 2 GTC identified as the “posterior margin of the nasoantorbital fenestra”. 3 4 5 The xiphiplastron is triangular in shape. The suture between the hypoplastron and 6 7 xiphiplastron is clearly visible on ODA-28, with a process on the xiphiplastron close to the 8 9 10 lateral edge fitting into a notch on the hypoplastron, as in other turtles. Among its most 11 12 striking features are the posterolateral skin sulcus (identified by GTC as the “nasal process”), 13 14 15 which in most turtles represents the attachment margin of the skin (body-wall), and the pubic 16 17 attachment area (identified by GTC as the “fossa”), where the lateral pubic process is 18 19 attached to the plastron by ligaments. This attachment site is often present in stem-turtles and 20 21 22 some cryptodires (in pleurodirans the contact is sutural) (see for e.g. Proganochelys, 23 24 meiolanids and Glyptops; Gaffney, 1990). In Kallokibotion the pubic articular facet is present 25 26 27 on the centro-lateral part of the xiphiplastron and is oval or subrounded in shape (Natural 28 29 History Museum, London; NHMUK R4930), nearly identical in shape, size, and position to 30 31 32 the „fossa‟ on ODA-28 (Fig. 1). 33 34 ODA-28 also exhibits several other uncanny similarities with Kallokibotion and other 35 36 turtles. The visceral (=dorsal) surface of the hypo-xiphiplastron is generally smooth but 37 38 39 exhibits a series of fine lineations, which are especially concentrated close to the inguinal 40 41 process, along the sutural margins and radiating around the pubic articular facet. This specific 42 43 44 type of plastron texture is common in many turtles and marks both soft tissue attachments 45 46 and a small degree of surface vascularization. Additionally, features identified by GTC as the 47 48 49 “trabecular” internal structure of the bone (clearly distinct from the condition present in 50 51 pterosaur cranial crests; see above) is common in turtles and usually formed by a highly 52 53 vascularized external cortex, an extensive interior cancellous area formed by short and thick 54 55 56 trabeculae, and a relatively thin, fibrolamellar internal cortex. 57 58 59 60 61 62 63 64 6 65 The morphology of the hypoplastron and xiphiplastron, and in particular the size and 1 2 shape of the inguinal buttress, the orientation of the meso-hypoplastral suture (indicating the 3 4 5 presence of a wide triangular mesoplastron), the development of the xiphiplastral skin sulcus, 6 7 and the size and position of the pubic articular facet, clearly indicate referral of ODA-28 to 8 9 10 the turtle Kallokibotion, and it is a perfect match to NHMUK R4930, the lectotype of 11 12 Kallokibotion magnificum Nopcsa 1923 (Fig 1) (this species was synonymised with K. 13 14 15 bajazidi by Gaffney and Meylan, 1992; see Rabi et al., 2013). 16 17 18 19 4. Evolutionary implications 20 21 22 Based on their incorrect identification of ODA-28 as a pterosaur crest, GTC built a 23 24 classic „house of cards‟ scenario: the misidentification of one fragmentary fossil leading to a 25 26 27 cascade of elaborate ideas with increasingly far-reaching implications. These include bizarre 28 29 and implausible soft-tissue and ecological hypotheses: e.g. the crest anchored muscles and a 30 31 32 „sizeable fleshy crest‟ and acted as a rudder in flight; this supposed new pterosaur 33 34 demonstrates hitherto unappreciated co-evolution between Romanian pterosaurs and 35 36 angiosperms, and; the hypothesis that their new taxon supports ecological segregation 37 38 39 between azhdarchids and thalassodromines. None of these hypotheses are supported now that 40 41 ODA-28 is identified as a turtle. 42 43 44 45 46 5. Conclusions 47 48 49 The new Romanian fossil ODA-28 described by GTC shares no apomorphic characters 50 51 with pterosaurs, lacks the microstructure and anatomical features of pterosaur head crests, 52 53 and shares numerous features with Kallokibotion and other turtles. We therefore reassign 54 55 56 ODA-28 to the common Upper Cretaceous European turtle Kallokibotion. Additional 57 58 preparation and study of ODA-28 is almost certain to corroborate our re-identification. We 59 60 61 62 63 64 7 65 predict that histological thin sectioning will demonstrate characteristic turtle, not pterosaur, 1 2 internal texture and vascularization patterns. We also predict that preparation of the other side 3 4 5 of ODA-28 will reveal the fine vermicular texture and sulci for the dermal scales across the 6 7 hypoplastron and xiphiplastron, as is characteristic for turtles and which clearly would not be 8 9 10 present in a pterosaur. Finally we predict that preparation or CT scanning of the embedded 11 12 side will reveal the full asymmetric three-dimensional morphology expected for a turtle 13 14 15 plastron but not for a symmetrical pterosaur head crest. We are currently not able to perform 16 17 these analyses, as the specimen is inaccessible to us (V. Codrea, pers. comm. to G. Dyke, 18 19 July 2014), but look forward to the additional data GTC will bring on this intriguing fossil. 20 21 22 The name Thalassodromeus sebesensis Grellet-Tinner and Codrea, 2014 should be 23 24 synonymised under Kallokibotion bajazidi. 25 26 27 28 29 References 30 31 32 Frey, E., Tischlinger, H., Buchy, M-C., Martill, D. M. 2003. New specimens of Pterosauria 33 34 (Reptilia) with soft parts with implications for pterosaurian anatomy and locomotion. 35 36 Buffetaut, E., Mazin, J-M. (eds) Evolution and Palaeobiology of Pterosaurs. Geological 37 38 39 Society, London, Special Publications, 217, 233‒266. 40 41 Gaffney, E. S. 1990. The comparative osteology of the Triassic turtle Proganochelys. 42 43 44 Bulletin of the American Museum of Natural History 194, 1-263. 45 46 Gaffney, E. S. and Meylan, P. A. 1992. The Transylvanian turtle Kallokibotion, a primitive 47 48 49 Cryptodire of Cretaceous age. American Museum Novitates, 3040, 1-37. 50 51 Grellet-Tinner, G., Codrea, V.A., in press. Thalassodromeus sebesensis, an out of place and 52 53 out of time Gondwanan tapejarid pterosaur. Gondwana Research, xxx-xxx. 54 55 56 Grellet-Tinner, G., Codrea, V., Solomon, A.L., 2013. Thalassodromeus sebesensis: a 42 57 58 59 60 61 62 63 64 8 65 million year anachronistic new crested pterosaur species from the Cretaceous Haţeg Island. 1 2 The 9th Romanian Symposium on Paleontology, Iasi, Abstract vol. p. 46-47. 3 4 5 Kellner, A. W. A., Campos, D. A. 2002. Form, function, and the flight of the pterosaur - 6 7 response. Science, 297: 2207-2208 (10.1126/science.297.5590.2207b). 8 9 10 Kellner, A. W. A., Campos, D. A. 2007. Short note on the ingroup relationships of the 11 12 Tapejaridae (Pterosauria, Pterodactyloidea). Boletim do Museu Nacional, Nova Série 13 14 15 Geologia, 75, 1–14. 16 17 Martill, D. M., Naish, D. 2006. Cranial crest development in the azhdarchoid pterosaur 18 19 Tupuxuara, with a review of the genus and tapejarid monophyly. Palaeontology, 49, 20 21 22 925–941. 23 24 Nopcsa, F. (1923a). On the geological importance of the primitive reptilian fauna in the 25 26 27 Uppermost Cretaceous: with a description of a new tortoise (Kallokibotion). Quarterly 28 29 Journal of the Geological Society, 79, 100–16. 30 31 32 Nopcsa, F. (1923b). Kallokibotion, a primitive amphychelidean tortoise from the uppermost 33 34 Cretaceous of Hungary. Paleontologia Hungarica, 1, 1–34, Budapest. 35 36 Rabi, M., Vremir, M., Tong, H., 2013. Preliminary overview of Late Cretaceous turtle 37 38 39 diversity in Eastern Central Europe (Austria, Hungary, and Romania). In: Brinkman, 40 41 D.B., Holroyd, P.A., Gardner, J.D. (Eds.), Morphology and Evolution of Turtles. 42 43 44 Vertebrate Paleobiology and Paleoanthropology. Springer Science+Business Media, 45 46 Dordrecht, pp. 307–336. 47 48 49 de Ricqles, A. J., Padian, K., Horner, J. R. 2000. Palaeohistology of the bones of pterosaurs 50 51 (Reptilia: Archosauria): anatomy, ontogeny, and biomechanical implications. 52 53 Zoological Journal of the Linnean Society, 129, 349–385. 54 55 56 Sayão, J. M. 2003. Histovariability in bones of two pterodactyloid pterosaurs from the 57 58 Santana Formation, Araripe Basin, Brazil: preliminary results. Buffetaut, E., Mazin, J- 59 60 61 62 63 64 9 65 M. (eds) Evolution and Palaeobiology of Pterosaurs. Geological Society, London, 1 2 Special Publications, 217, 335‒342. 3 4 5 Steel, L., Martill, D. M, Unwin, D. M., Winch, J. D. 2005. A new pterodactyloid pterosaur 6 7 from the Wessex Formation (Lower Cretaceous) of the Isle of Wight, England. 8 9 10 Cretaceous Research, 26, 686‒698. 11 12 Steel, L. 2008. The palaeohistology of pterosaur bone: an overview. Zitteliana, B28, 13 14 15 109‒125. 16 17 Witton, M. P. 2009. A new species of Tupuxuara (Thalassodromidae, Azhdarchoidea) from 18 19 the Lower Cretaceous Santana Formation of Brazil, with a note on the nomenclature of 20 21 22 Thalassodromidae. Cretaceous Research, 30, 1293–1300. 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 10 65 Figure Caption 1 2 3 4 Fig. 1. The turtle affinities of ODA-28. (A) NHMUK R4930, the lectotype plastron of 5 6 Kallokibotion magnificum Nopcsa 1923, with the portion corresponding to ODA-28 outlined 7 8 in black (photo supplied by S. Chapman, Natural History Museum, London). (B) ODA-28 9 10 11 (modified from Grellet-Tinner & Codrea, 2014). Abbreviations: hypo, hypoplastron; hxc, 12 13 hypoplastron-xiphiplastron suture; ihc, intra-hypoplastral suture; ib, inguinal buttress; ps, 14 15 16 pubic scar; meso, mesoplastron; mhc, meso-hypoplastral contact; pll, posterolateral lip; xiphi, 17 18 xiphiplastron. Scale bar for A equals 5 cm. 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 11 65 Fig.1 Click here to download high resolution image