Schizorhiza

Schizorhiza
Temporal range: Campanian–Maastrichtian
Schizorhiza stromeri rostrum
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Order: Rajiformes
Family: †Schizorhizidae
Genus: †Schizorhiza
Weiler, 1930[1]
Species:
†S. stromeri
Binomial name
†Schizorhiza stromeri
Weiler, 1930
Synonyms
  • Schizorhiza weileri Serra, 1933[2]

Schizorhiza is an extinct genus of schizorhizid sclerorhynchoid that lived during the Late Cretaceous. It contains one valid species, Schizorhiza stromeri. It lived from the Campanian to Maastrichtian,[3] and its fossils have been found in Africa, the Middle East, North America, and South America.[4]

Taxonomy

Schizorhiza stromeri was named by Wilhelm Weiler in 1930 for rostral denticles from the Nubian Sandstone of Egypt. The species was named in honor of Ernst Stromer.[1] A second species, S. weileri, was named by Giselda Serra in 1933 for rostral denticles from Libya.[2] It is considered a junior synonym of S. stromeri.[5]

Description

Schizorhiza is characterized by its robust rostrum with over 1,800 denticles arranged in dense batteries, which form a continuous cutting edge along each side.[5] Each denticle was replaced by a series of smaller denticles nested inside its roots and new rows of denticles grew from the end of the rostrum.[6] Among sclerorhynchoids, this denticle arrangement and replacement system is only found in Schizorhiza and its close relative Harranahynchus.[7] The rostrum was likely used for swiping and slicing prey like sawfishes[5] and has earned Schizorhiza the common name of "slasher ray".[8]

References

  1. ^ a b Weiler, W. (1930). "Ergebnisse der Forschungsreisen Prof. E. Stromers in den Wüsten Ägyptens. VI. Beschreibung von Wirbeltier-Resten aus dem nubischen Sandsteine Oberägyptens und aus ägyptischen Phosphaten nebst Bemerkungen über die Geologie der Umgegend von Mahamîd in Oberägypten. Fischreste aus dem nubischen Sandstein von Mahamîd und Edfu und aus den Phosphaten Oberägyptens und der Oase Baharîje". Abhandlungen der Bayerischen Akademie der Wissenschaften, Mathematisch-naturwissenschaftliche Abteilung. 7: 12–36.
  2. ^ a b Serra, G. (1933). "Di una nuova specie di Schizorhiza del Maestrichtiano della Tripolitania". Rivista Italiana di Paleontologia. 39: 103–108.
  3. ^ Becker, Martin A.; Chamberlain Jr, John A.; Wolf, George E. (2006). "Chondrichthyans from the Arkadelphia Formation (Upper Cretaceous: Upper Maasstrichtian) of Hot Spring County, Arkansas". Journal of Paleontology. 80 (4): 700–716. doi:10.1666/0022-3360(2006)80[700:CFTAFU]2.0.CO;2.
  4. ^ Cappetta, H. (2012). Handbook of Paleoichthyology. Volume 3E. Chondrichthyes. Mesozoic and Cenozoic Elasmobranchii: Teeth. Munich: Verlag Dr. Friedrich Pfeil. ISBN 978-3-89937-148-2.
  5. ^ a b c Kirkland, J.I.; Aguillón-Martínez, M.C. (2002). "Schizorhiza: a unique sawfish paradigm from the Difunta Group, Coahuila, Mexico". Revista Mexicana de Ciencias Geológicas. 19 (1): 16–24.
  6. ^ Smith, M.M.; Riley, A.; Fraser, G.J.; Underwood, C.; Welten, M.; Kriwet, J.; Pfaff, C.; Johanson, Z. (2015). "Early development of rostrum saw-teeth in a fossil ray tests classical theories of the evolution of vertebrate dentitions". Proceedings of the Royal Society B: Biological Sciences. 282 (1816): 20151628. doi:10.1098/rspb.2015.1628. PMC 4614774. PMID 26423843.
  7. ^ Kaddumi, H.F. (2009). "A new genus and species of sawfishes (Chondrichthyes: Batoidea) from the late Maastrichtian sediments of Harrana". Fossils of the Harrana Fauna and the Adjacent Areas. Eternal River Museum of Natural History. pp. 178–187.
  8. ^ Gibson, S.Z. (2015-10-30). "The "slasher" ray: An extinct fish with a saw-like nose". PLOS Paleo. Archived from the original on 2015-10-31. Retrieved 2023-03-20.