The Science of Nature

, 103:95 | Cite as

A new armored archosauriform (Diapsida: Archosauromorpha) from the marine Middle Triassic of China, with implications for the diverse life styles of archosauriforms prior to the diversification of Archosauria

Original Paper

Abstract

Reptiles have a long history of transitioning from terrestrial to semi-aquatic or aquatic environments that stretches back at least 250 million years. Within Archosauria, both living crocodylians and birds have semi-aquatic members. Closer to the root of Archosauria and within the closest relatives of the clade, there is a growing body of evidence that early members of those clades had a semi-aquatic lifestyle. However, the morphological adaptations to a semi-aquatic environment remain equivocal in most cases. Here, we introduce a new Middle Triassic (245–235 Ma) archosauriform, Litorosuchus somnii, gen. et sp. nov., based on a nearly complete skeleton from the Zhuganpo Member (Ladinian [241–235 Ma]) of the Falang Formation, Yunnan, China. Our phylogenetic analyses suggest that Litorosuchus is a stem archosaur closely related to the aberrant Vancleavea just outside of Archosauria. The well-preserved skeleton of L. somnii bears a number of morphological characters consistent with other aquatic-adapted tetrapods including: a dorsally directed external naris, tall neural spines and elongate chevrons in an elongated tail, a short and broad scapula, webbed feet, long cervical vertebrae with long slender ribs, and an elongated rostrum with long and pointed teeth. Together these features represent one of the best-supported cases of a semi-aquatic mode of life for a stem archosaur. Together with Vancleavea campi, the discovery of L. somnii demonstrates a growing body of evidence that there was much more diversity in mode of life outside Archosauria. Furthermore, L. somnii helps interpret other possible character states consistent with a semi-aquatic mode of life for archosauriforms, including archosaurs.

Keywords

Reptile Morphology Phylogeny Adaptation Semi-aquatic 

Notes

Acknowledgments

We are grateful to J-Z Ding (IVPP) for skillful preparation of the specimen used in this study, W Gao (IVPP) for photographic work, and Y Chen for the first draft of the skeletal reconstruction. X-CW particularly wishes to thank the IVPP and Zhejiang Museum of Natural History, Hangzhou, China (ZMNH) for hospitality during his visits. H-D Sues, S Brusatte, and an anonymous reviewer carefully reviewed the manuscript, offering critical comments and suggestions that led to its great improvement. This work was supported by research grants from the National Natural Science Foundation of China (NNSFC-41172027 and 41472020 to L-JZ and X-CW), from State Key Laboratory of Palaeobiology and Stratigraphy of Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences (no. 153105 to CL), from Canadian Museum of Nature (RCP09 to X-CW) as well as from generous supports from the IVPP (to CL), from the ZMNH (to L-JZ), and from the Department of Geosciences at Virginia Tech (to SJN and MRS).

Supplementary material

114_2016_1418_MOESM1_ESM.docx (1.9 mb)
ESM 1 (DOCX 1972 kb)

References

  1. Alcober O (2000) Redescription of the skull of Saurosuchus galilei (Archosauria: Rauisuchidae). J Vert Paleontol 20:302–316CrossRefGoogle Scholar
  2. Arcucci AB (1990) Un nuevo Proterochampsidae (Reptilia―Archosauriformes) de la fauna local de los Chañares (Triasico medio), La Rioja, Argentina (A new Proterochampsid (Reptilia-Archosauriformes) from the local fauna of Los. Chañares, Middle Triassic of La Rioja, Argentine). Ameghiniana 27:365–378Google Scholar
  3. Benton MJ (1985) Classification and phylogeny of the diapsid reptiles. Zool J Linnean Soc 84:97–164CrossRefGoogle Scholar
  4. Butler RJ, Sullivan C, Ezcurra MD, Liu J, Lecuona A, Sookias RB (2014) New clade of enigmatic early archosaurs yields insights into early pseudosuchian phylogeny and the biogeography of the archosaur radiation. BMC Evol Biol 14:128–144CrossRefPubMedPubMedCentralGoogle Scholar
  5. Camp CL (1930) A study of the phytosaurs with description of new material from western North America. University of California Mem 10:1–174Google Scholar
  6. Carroll RL (1988) Vertebrate palaeontology and evolution. W H Freeman and Company, New YorkGoogle Scholar
  7. Chatterjee S (1993) Shuvosaurus, a new theropod. Natl Geogr Res Explor 9:274–285Google Scholar
  8. Chen Z (1985) Stratigraphical position of Keichousaurus hui Young from the Middle Triassic of southwestern Guizhou and its significance. Guizhou Geol 5:289–290 ChineseGoogle Scholar
  9. Cheng Y-N, Wu X-C, Ji Q (2004) Triassic marine reptile gave birth of live young. Nature 432:383–386CrossRefPubMedGoogle Scholar
  10. Cheng Y-N, Sato T, Wu X-C, Li C (2006) First complete pistosauroid from the Triassic of China. J Vert Paleontol 26:501–504CrossRefGoogle Scholar
  11. Cheng Y-N, Wu X-C, Sato T, Shan H-Y (2012) A new eosauropterygian (Diapsida, Sauropterygia) from the Triassic of China. J Vert Paleontol 32:1335–1349CrossRefGoogle Scholar
  12. Cheng L, Chen X, Shang Q, Wu X­C (2014) A new marine reptile from the Triassic of China, with a highly specialized feeding adaptation. Naturwissenschaften 101:251–259CrossRefPubMedGoogle Scholar
  13. Chinsamy A, Martin LD, Dobson P (1998) Bone microstructure of the diving Hesperornis and the volant Ichthyornis from the Niobrara Chalk of western Kansas. Cretac Res 19(2):225–235CrossRefGoogle Scholar
  14. Cong L-Y, Hou L-H, Wu X-C, Hou J-F (1998) The gross anatomy of Alligator sinensis Fauvel. Science Press, BeijingGoogle Scholar
  15. Desojo JB, Ezcurra MD, Schultz CL (2011) An unusual new archosauriform from the Middle–Late Triassic of southern Brazil and the monophyly of Doswelliidae. Zoo J Linn Soc 161(4):839–871CrossRefGoogle Scholar
  16. Desojo JB, Heckert AB, Martz JW, Parker WG, Schoch RR, Small BJ, Sulej T (2013) Aetosauria: a clade of armoured pseudosuchians from the Upper Triassic continental beds. In: Nesbitt SJ, Desojo JB, Irmis RB (eds) Anatomy, phylogeny and palaeobiology of Early Archosaurs and their Kin. Geol Soc Lond Spec Pub 379, pp. 203–239Google Scholar
  17. Dilkes D, Sues H-D (2009) Redescription and phylogenetic relationships of Doswellia kaltenbachi (Diapsida: Archosauriformes) from the Upper Triassic of Virginia. J Vert Paleontol 29:58–79CrossRefGoogle Scholar
  18. Dzik J (2003) A beaked herbivorous archosaur with dinosaur affinities from the early Late Triassic of Poland. J Vert Paleontol 23:556–574CrossRefGoogle Scholar
  19. Ewer RF (1965) The anatomy of the thecodont reptile Euparkeria capensis Broom. Phil Trans R Soc Lond B 248:379–435CrossRefGoogle Scholar
  20. Ezcurra MD, Butler RJ, Gower DJ (2013) ‘Proterosuchia’: the origin and early history of Archosauriformes. In: Nesbitt SJ, Desojo JB, Irmis RB (eds) Anatomy, phylogeny and palaeobiology of Early Archosaurs and their Kin. Geol Soc Lond Spec Pub 379, pp. 9–33Google Scholar
  21. Gauthier JA, Kluge AG, Rowe T (1988) The early evolution of the Amniota; pp. 103–155 in Benton MJ (ed), The Phylogeny and Classification of the tetrapods, volume 1: Amphibia, Reptilia, Birds. Syst Asso Special, vol 45 A. Clarendon Press, OxfordGoogle Scholar
  22. Gower DJ (1997) The braincase of the early archosaurian reptile Erythrosuchus africanus. J Zool Lond 242:557–576CrossRefGoogle Scholar
  23. Gower DJ (2003) Osteology of the early archosaurian reptile Erythrosuchus africanus Broom. Ann South Afr Mus 110:1–84Google Scholar
  24. Gower DJ, Schoch RR (2009) Postcranial anatomy of the rauisuchian archosaurian Batrachotomus kuperferzellensis. J Vertebr Paleontol 29:103–122CrossRefGoogle Scholar
  25. Gower DI, Weber E (1998) The braincase of Euparkeria, and the evolutionary relationships of birds and crocodilians. Biol Rev 73:367–411CrossRefGoogle Scholar
  26. Gozzi E, Renesto SA (2003) Complete specimen of Mystriosuchus (Reptilia, Phytosauria) from the Norian (Late Triassic) of Lombardy (Northern Italy). Rivista Italiana Di Paleontolo Stratigr 109:475–498Google Scholar
  27. Heckert AB, Lucas SG, Spielmann JA (2012) A new species of the enigmatic archosauromorph Doswellia from the Upper Triassic Bluewater Creek Formation, New Mexico, USA. Palaeontol 55(6):1333–1348CrossRefGoogle Scholar
  28. Hunt AP (1989) Cranial morphology and ecology among phytosaurs. In: Lucas SG, Hunt AP (eds) Dawn of the age of dinosaurs in the American southwest. New Mexico Museum of Natural History and Science, Albuquerque, NM, pp. 349–354Google Scholar
  29. Ibrahim N, Sereno PC, Sasso CD, Maganuco S, Fabbri M, Martill DM, Zouhri S, Myhrvold N, Iurino DA (2014) Semiaquatic adaptations in a giant predatory dinosaur. Science 345(6204):1613–1616CrossRefPubMedGoogle Scholar
  30. Kammerer CF, Butler RJ, Bandyopadhyay S, Stocker MR (2015) Relationships of the Indian phytosaur Parasuchus hislopi Lydekker, 1885. Papers in Palaeon. doi: 10.1002/sppe.1022 Google Scholar
  31. Kelley NP, Pyenson ND (2015) Evolutionary innovation and ecology in marine tetrapods from the Triassic to the Anthropocene. Science 348(6232):3716CrossRefGoogle Scholar
  32. Krebs B (1965) Die Triasfauna der Tessiner Kalkalpen. XIX. Ticinosuchus ferox, nov. gen. nov. sp. Ein neuer Pseudosuchier aus der Trias des Monte San Georgio. Schweizersiche Palaontol Abhandlungen 81:1–140Google Scholar
  33. Langer MC, Nesbitt SJ, Bittencourt JS, Irmis RB (2014) Non-dinosaurian Dinosauromorpha. In: Nesbitt SJ, Desojo JB, Irmis RB (eds) Anatomy, phylogeny and palaeobiology of Early Archosaurs and their Kin. Geol Soc Lond Spec Pub 379, pp. 157–186Google Scholar
  34. Li C (2007) A juvenile Tanystropheus sp. (Protorosauria: Tanystropheidae) from the Middle Triassic of Guizhou, China. Vert PalAsiat 45:37–42Google Scholar
  35. Li J-L, Liu J, Rieppel O (2002) A new species of Lariosaurus (Sauropterygia: Nothosauridae) from Triassic of Guizhou, southwestern China. Vert PalAsiat 40:114–126Google Scholar
  36. Li C, Rieppel O, LaBarbera MC (2004) A Triassic aquatic protorosaur with an extremely long neck. Science 305:1931CrossRefPubMedGoogle Scholar
  37. Li C, Wu X-C, Cheng Y-N, Sato T, Wang L-T (2006) An unusual archosaurian from the marine Triassic of China. Naturwiss 93:200–206CrossRefPubMedGoogle Scholar
  38. Li C, Zhao L-J, Wang L-T (2007) A new species of Macrocnemus (Reptilia: Protorosauria) from the middle Triassic of southwestern China and its palaeogeographical implications. Sci China S D (Earth Sciences) 50:1601–1605CrossRefGoogle Scholar
  39. Li C, Wu X-C, Zhao L-J, Sato T, Wang L-T (2012) A new archosaur (Diapsida, Archosauriformes) from the marine Triassic of China. J Vert Paleontol 32(5):1064–1081CrossRefGoogle Scholar
  40. Liu J, Rieppel O (2005) Restudy of Anshunsaurus huangguoshuensis (Reptilia: Thalattosauria) from the Middle Triassic of Guizhou, China. Amer Mus Nov 3488:1–34CrossRefGoogle Scholar
  41. Long RA, Murry PA (1995) Late Triassic (Carnian and Norian) tetrapods from the southwestern United States. N M Mus Nat Hist Sci Bull 4:1–254Google Scholar
  42. Nesbitt SJ (2007) The anatomy of Effigia okeeffeae (Archosauria, Suchia), theropod convergence, and the distribution of related taxa. Bull Amer Mus Nat Hist 302:1–84CrossRefGoogle Scholar
  43. Nesbitt SJ (2011) The early evolution of archosaurians: relationships and the origin of major clades. Bull Amer Mus Nat Hist 352:1–292CrossRefGoogle Scholar
  44. Nesbitt SJ, Stocker MR, Small BJ, Downs A (2009) The osteology and relationships of Vancleavea campi (Reptilia: Archosauriformes). Zool J Linn Soc Lond 157:814–864CrossRefGoogle Scholar
  45. Nicholls EL, Brinkman DB, Wu X-C (1998) A new archosaur from the Upper Triassic Pardonet Formation of British Columbia. Can J Earth Sci 35:1134–1142CrossRefGoogle Scholar
  46. Osborn HF (1903) The reptilian subclasses Diapsida and Synapsida and the early history of the Dinosauria. Mem Amer Mus Nat Hist 1:449–507Google Scholar
  47. Parker WG (2007) Reassessment of the aetosaur ‘Desmatosuchuschamaensis with a reanalysis of the phylogeny of the Aetosauria (Archosauria: Pseudosuchia). J Syst Palaeontol 5:41–68CrossRefGoogle Scholar
  48. Parker WG, Barton BJ (2008) New information on the Upper Triassic archosauriform Vancleavea campi based on new material from the Chinle Formation of Arizona. Palaeontol Electron 11(3):14A 11-20Google Scholar
  49. Parrish JM (1992) Phylogeny of the Erythrosuchidae. J Vertebr Paleont 12:93–102CrossRefGoogle Scholar
  50. Rieppel O, Liu J, Li C (2006) A new species of the thalattosaur genus Anshunsaurus (Reptilia: Thalattosauria) from the Middle Triassic of Guizhou Province, southwestern China. Vert PalAsiat 44:285–296Google Scholar
  51. Rieppel O, Jiang D-Y, Nicholas FC, Hao W-C, Motani R, Sun Y-L, Sun Z-Y (2010) Tanystropheus cf. T. longobardicus from the early Late Triassic of Guizhou Province, southwestern China. J Vertebr Paleontol 30:1082–1089CrossRefGoogle Scholar
  52. Romer AS (1971) The Chañares (Argentina) Triassic reptile fauna. X. Two new but incompletely known long-limbed pseudosuchians. Breviora 378:1–10Google Scholar
  53. Romer AS (1972) The Chañares (Argentina) Triassic reptile fauna. XII. The postcranial skeleton of the thecodont Chanaresuchus. Breviora 385:1–21Google Scholar
  54. Sato T, Cheng Y-N, Wu X-C, Li C (2010) Osteology of Yunguisaurus Cheng et al., 2006 (Reptilia; Sauropterygia), a Triassic pistosauroid from China. Paleontol Res 14:179–195CrossRefGoogle Scholar
  55. Schoch RR (2007) Osteology of the small archosaur Aetosaurus from the Upper Triassic of Germany. N Jb Geol Paläontol 246:1–35CrossRefGoogle Scholar
  56. Schoch RR, Sues H-D (2013) A new archosauriform reptile from the Middle Triassic (Ladinian) of Germany. J Sys Palaeontol 12(1):113–131CrossRefGoogle Scholar
  57. Seebacher F, Elsworth PG et al (2003) Ontogenetic changes of swimming kinematics in a semi-aquatic reptile (Crocodylus porosus). Australian Journal of Zoology 51(1):15–24CrossRefGoogle Scholar
  58. Sereno PC (1991) Basal archosaurs: phylogenetic relationships and functional implications. Mem Soc Vert Paleontol 2:1–53CrossRefGoogle Scholar
  59. Sookias RB, Butler RJ (2013) Euparkeriidae. In: Nesbitt SJ, Desojo JB, Irmis RB (eds) Anatomy, Phylogeny and Palaeobiology of Early Archosaurs and their Kin. Geol Soc Lond Spec Pub 379, pp. 35–48Google Scholar
  60. Stocker MR (2010) A new taxon of phytosaur (Archosauria: Pseudosuchia) from the Late Triassic (Norian) Sonsela member (Chinle formation) in Arizona, and a critical reevaluation of Leptosuchus case, 1922. Palaeontol 53:997–1022CrossRefGoogle Scholar
  61. Stocker MR, Butler RJ (2013) Phytosauria. In: Nesbitt SJ, Desojo JB, Irmis RB (eds) Anatomy, phylogeny and palaeobiology of Early Archosaurs and their Kin. Geol Soc Lond Spec Pub 379, pp. 91–117Google Scholar
  62. Sues H-D, Desojo JB, Ezcurra MD (2013) Doswelliidae: a clade of unusual armoured archosauriforms from the Middle and Late Triassic. In: Nesbitt SJ, Desojo JB, Irmis RB. (eds) Anatomy, phylogeny and palaeobiology of Early Archosaurs and their Kin. Geol Soc Lond Spec Pub 379, pp. 49–58Google Scholar
  63. Swofford DL (2002) PAUP* phylogenetic analysis using parsimony (and other methods) 4.0b10. Sinauer Associates, Sunderland, MassachusettsGoogle Scholar
  64. Thomas DB, Fordyce RE (2012) Biological plasticity in penguin heat-retention structures. Anat Rec 295(2):249–256CrossRefGoogle Scholar
  65. Trotteyn MJ, Haro JA (2011) The braincase of a specimen of Proterochampsa Reig (Archosauriformes: Proterochampsa) from the Late Triassic of Argentina. Paläontol Z 85:1–17CrossRefGoogle Scholar
  66. Trotteyn MJ, Martínez RN, Alcober OA (2012) A new proterochampsid Chanaresuchus ischigualastensis (Diapsida, Archosauriformes) in the early Late Triassic Ischigualasto Formation, Argentina. J Vert Paleontol 32:485–489CrossRefGoogle Scholar
  67. Trotteyn MJ, Arcucci AB, Raugust T (2013) Proterochampsia: an endemic archosauriform clade from South America. In: Nesbitt SJ, Desojo JB, Irmis RB. (eds) Anatomy, phylogeny and palaeobiology of Early Archosaurs and their Kin. Geol Soc Lond Spec Pub 379, pp. 59–90Google Scholar
  68. von Huene F (1946) Die grossen Stämme der Tetrapoden in den geologischen Zeiten. Biol Zentral 65:268–275Google Scholar
  69. Wang X, Bachmann GH, Hagdorn H, Sander M, Cuny G, Chen X, Wang C, Chen L, Cheng L, Meng F, Xu G (2008) The Late Triassic black shales of the Guanling area, Guizhou province, south-West China: a unique marine reptile and pelagic crinoid fossil lagerstätten. Palaeotol 51:27–61Google Scholar
  70. Wang R, Xu S, Wu X, Wang LC (2013) A new specimen of Shansisuchus shansisuchus Young, 1964 (Diapsida: Archosauriformes) from the Triassic of Shanxi, China. Acta Geol Sinica 87:1185–1197CrossRefGoogle Scholar
  71. Weems RE (1980) An unusual newly discovered archosaur from the Upper Triassic of Virginia, U.S.A. Trans Amer Phil Soc New Series 70(7):1–53CrossRefGoogle Scholar
  72. Weinbaum JC (2014) Postcranial skeleton of Postosuchus kirkpatricki (Archosauria: Paracrocodylomorpha), from the Upper Triassic of the United States. In: Nesbitt SJ, Desojo JB, Irmis RB (eds) Anatomy, phylogeny and palaeobiology of Early Archosaurs and their Kin. Geol Soc Lond Spec Pub 379, pp. 525–553Google Scholar
  73. Wu X-C, Russell AP (2001) Redescription of Turfanosuchus dabanensis (Archosauriformes) and new information on its phylogenetic relationships. J Vert Paleontol 21:40–50CrossRefGoogle Scholar
  74. Wu X-C, Cheng Z-W, Russell AP (2001) Cranial anatomy of a new crocodyliform (Archosauria: Crocodylomorpha) from the Lower Cretaceous of Song-Liao Plain, northeastern China. Can J Earth Sci 38:1653–1663CrossRefGoogle Scholar
  75. Wu X-C, Chun Y-N, Sato T, Shan H-Y (2009) Miodentosaurus brevis Cheng et al., 2007 (Diapsida: Thalattosauria): its postcranial skeleton and phylogenetic relationships. Vert PalAsiat 47:1–12Google Scholar
  76. Young CC (1964) The pseudosuchians in China. Palaeontol Sinica 151:1–205Google Scholar
  77. Zhao L-J, Sato T, Li C (2008a) The most complete pistosauroid skeleton from the Triassic of Yunnan, China. Acta Geol Sinica 82:283–286Google Scholar
  78. Zhao L-J, Wang L-T, Li C (2008b) Review and prospect of the Triassic marine reptiles in China. Acta Palaeontol Sinica 47:99–106Google Scholar
  79. Zhao L-J, Li C, Liu J, He T (2008c) A new armored placodont from the Middle Triassic of Yunnan Province, southwestern China. Vert PalAsiat 46:171–177Google Scholar
  80. Zhao L-J, Sato T, Liu J, Li C, Wu X-C (2010) A new skeleton of Miodentosaurus brevis (Diapsida: Thalattosauria) with a further study of the taxon. Vert PalAsiat 48:1–10Google Scholar

Copyright information

© Her Majesty the Queen in Right of Canada as represented by: Canadian Museum of Nature 2016

Authors and Affiliations

  1. 1.Laboratory of Evolutionary Systematics of Vertebrates, Institute of Vertebrate Paleontology and PaleoanthropologyChinese Academy of SciencesBeijingPeople’s Republic of China
  2. 2.Canadian Museum of NatureOttawaCanada
  3. 3.Zhejiang Museum of Natural HistoryHangzhouChina
  4. 4.Department of GeosciencesVirginia Polytechnic Institute and State UniversityBlacksburgUSA
  5. 5.Geological Survey of Guizhou ProvinceGuiyangChina

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