First skeletal remains of the giant sawfish Onchosaurus (Neoselachii,Sclerorhynchiformes) from the Upper Cretaceous of northeastern Italy |
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| Institution: | 1. Department of Geosciences, University of Padova, Via G. Gradenigo 6, 35131, Padova, Italy;2. University of Vienna, Department of Paleontology, Geozentrum, Althanstrasse 14, 1090, Vienna, Austria;3. Soprintendenza per i Beni Archeologici del Friuli Venezia Giulia, Nucleo Operativo di Udine, Via Zanon, 22 I, 33100, Udine, Italy;1. Department of Zoology, Oxford University, South Parks Road, Oxford OX1 3PS, United Kingdom;2. Schmalhausen Institute of Zoology, National Academy of Sciences of Ukraine, 15 B. Khmelnitsky Street, Kiev 01-601, Ukraine;3. Division of Entomology, Natural History Museum, 1501 Crestline Drive – Suite 140, University of Kansas, Lawrence, KS 66045-4415, USA;4. Department of Ecology & Evolutionary Biology, University of Kansas, Lawrence, KS 66045, USA;5. Division of Invertebrate Zoology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024-5192, USA;1. Division of Entomology, Natural History Museum, 1501 Crestline Drive – Suite 140, University of Kansas, Lawrence, KS 66045-4415, USA;2. Department of Ecology & Evolutionary Biology, University of Kansas, Lawrence, KS 66045, USA;3. Division of Invertebrate Zoology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024-5192, USA;4. State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China;5. Key Laboratory of Economic Stratigraphy and Palaeogeography, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China;1. Department of Entomology, National Taiwan University, No.27, Lane 113, Sec. 4, Roosevelt Rd., Taipei, 106, Taiwan;2. Australian National Insect Collection, CSIRO, GPO Box 1700, Canberra, ACT 2601, Australia;3. State Key Laboratory of Biocontrol, Ecology and Evolution, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, Guangdong, China;4. College of Life Sciences, Capital Normal University, Xisanhuanbeilu 105, Haidian District, Beijing, 100048, China;1. University of Vienna, Department of Palaeontology, Geozentrum, Althanstraße 14, 1090 Vienna, Austria;2. Geological-Palaeontological Department, Natural History Museum, Burgring 7, 1010 Vienna, Austria;1. Programa de Pós-Graduação em Geociências (PPGGEO), Universidade Federal do Rio Grande do Sul (UFRGS), Avenida Bento Gonçalves 9500, 91501-970, Porto Alegre, RS, Brazil;2. Departamento de Paleontologia e Estratigrafia, Instituto de Geociências, Universidade Federal do Rio Grande do Sul (UFRGS), Avenida Bento Gonçalves 9500, 91501-970, Porto Alegre, RS, Brazil;3. Laboratório de Geologia e Paleontologia, Instituto de Oceanografia, Universidade Federal do Rio Grande (FURG), Avenida Itália km 8, 96201-900, Rio Grande, RS, Brazil;4. Museu de Ciências Naturais (MCN), Fundação Zoobotânica do Rio Grande do Sul (FZB), R. Dr. Salvador França, 90690-000, Porto Alegre, RS, Brazil |
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| Abstract: | Sclerorhynchiform sawfishes are a diverse and extinct clade of elasmobranchs that is restricted to the Cretaceous. Most taxa are known only by isolated rostral spines, whereas skeletal remains are rare and have been reported from a small number of Upper Cretaceous localities. Here, we describe skeletal remains of the giant sclerorhynchiform Onchosaurus pharao for the first time, which provides new morphological information. The single specimen comes from middle-basal upper Turonian strata of the Lessini Mountains in northeastern Italy and represents the first record of this genus from Italy. The specimen consists of unidentifiable cranial remains, several diagnostic rostral spines, the rostrum with fragments of tessellated calcified cartilage, and 87 disarticulated vertebrae. The rostrum preserves the characteristic sensory system of sclerorhynchiforms. It is devoid of any lateral sockets indicating that rostral spines were attached laterally to its surface. This pattern is identical to most sclerorhynchiforms and extant pristiophoriformes implying also similar replacement patterns as in most other sclerorhynchiforms with the exception for Schizorhiza. Additionally, the bases of two longitudinally arranged rows of ventral rostral spines are identifiable concurring with patterns seen in Sclerorhynchus. The axial skeleton is partly preserved. Re-arranging the disarticulated vertebrae according to their life position in combination with measures of the size and thickness of preserved vertebral centra, and the ratio rostrum length/body size depending on the number of vertebral centra indicate that the specimen was ca. 450 cm long. Growth rings in the vertebral centra show that the specimen was about four years old and thus probably not yet fully sexual mature when it died. This age assumption corresponds well with the calculated size when compared with complete skeletons of extinct sclerorhynchiforms and extant pristiforms. The size of the specimen and its occurrence in hemipelagic rocks corroborates previous assumptions that this sclerorhynchiform was a large and pelagic sawfish. |
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| Keywords: | Sclerorhynchidae Paleoecology Life history Turonian Lessini Mountains Northeastern Italy |
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