Aetosaurus was a small, primitive aetosaur. Unlike more derived aetosaurs such as Desmatosuchus or Typothorax, the carapace was long and narrow and lacked spikes. The paramedian scutes that covered the back (with one row on each side of the vertebrae) are considerably wider than they are long. The lateral scutes, which are beneath the paramedian and formed a row on either side of the animal, do not bear any spikes or other projections.[4]
Behaviouredit
A 2023 study based on a fossil assemblage found in Kaltental, suggested that juvenile A. ferratus were likely gregarious animals, possibly to increase their chances of survival and to deter predators.[8][9]
Speciesedit
Reconstructed skull of A. ferratus
Aetosaurus was first named, with the description of the type species A. ferratus, in 1877 by German paleontologistOscar Fraas. At the time, Aetosaurus was known from 22 articulated skeletons that had been found in the Lower Stubensandtein of Germany.[2] Thirty years later, Fraas' son Eberhard described a second species, A. crassicauda, also from Germany.[3]A. crassicauda can be distinguished from A. ferratus by its larger size; A. crassicauda reached a maximum length of 150 centimetres (59 in) while A. ferratus reached a length of up to 90 centimetres (35 in).[1]
In addition to the Stubensandtein in Germany, A. ferratus is also known from the Calcare di Zorzino Formation in Cene, Italy.[10] Specimens of Aetosaurus that have been recovered from the Fleming Fjord Formation in Greenland likely represent A. ferratus.[7] Some material from the Chinle Group in the southwestern United States probably represent A. ferratus, as well.[5][6]
In 1998, the genus Stegomus was synonymized with Aetosaurus.[4] In 1896, paleontologist Othniel Charles Marsh named Stegomus arcuatus from a cast of an aetosaur known as YPM 1647 from the New Haven Formation in the Fair Haven Heights neighborhood of New Haven.[11] This cast consisted of the dorsal carapace. Several other casts preserving the surface of the skull and tail have been found in the Passaic Formation of Hunterdon and Somerset counties, New Jersey[12][13] and an outcrop of the Lower Sanford Formation at the Triangle Brick Co. Quarry in Durham County, North Carolina.[14]Stegomus arcuatus was found to be synonymous with Aetosaurus on the basis of several similarities, including a lack of spikes and a distinctive radial pattern of grooves on some of the caudal scutes.[4]
Photograph of YPM 1647, a specimen of A. arcuatusSkeletal drawing of A. ferratus by Marsh
A. arcuatus has paramedian scutes that are much wider than they are long, even in comparison to other species of Aetosaurus. There is very little pitting on the surface of the scutes, although the porosity of the sandstone that makes up the casts has been mistaken for pitting.[15] The tail narrows significantly past the base. The carapace is "waisted", meaning that it narrows in front of the pelvis.[4]
The following cladogram is simplified after an analysis presented by Julia B. Desojo, Martin D. Ezcurra and Edio E. Kischlat (2012).[16]
^ abHeckert, A.B.; Lucas, S.G. (1999). "A new aetosaur (Reptilia: Archosauria) from the Upper Triassic of Texas and the phylogeny of aetosaurs". Journal of Vertebrate Paleontology. 19 (1): 50–68. Bibcode:1999JVPal..19...50H. CiteSeerX10.1.1.563.9516. doi:10.1080/02724634.1999.10011122.
^ abFraas, O. (1877). "Aetosaurus ferratus Fr. Die gepanzerte Vogel-Echse aus dem Stubensandstein bei Stuttgar". Festschrift zur Feier des 400jährigen Jubiläums der Eberhard-Karls-Universät zu Tübingen, Wurttembergische Naturwissenschaftliche Jahreshefte. 33 (3): 1–22.
^ abFraas, E. (1907). "Aëtosaurus crassicauda n. sp., nebst Beobachtungen tiber das Becken der Aëtosaurier". Jahreshefte des Vereins für Vaterländische Naturkunde Württemberg. 42: 101–109.
^ abcdeLucas, S.G.; Heckert, A.B.; Huber, P. (1998). (PDF). Palaeontology. 41 (6): 1215–1230. Archived from the original (PDF) on 2012-03-09.
^ abHeckert, A.B.; Lucas, S.G. (1998). "First occurrence of Aetosaurus (Reptilia: Archosauria) in the Upper Triassic Chinle Group (USA) and its biochronological significance". Neues Jahrbuch für Geologie und Paläontologie. 1998 (10): 604–612. doi:10.1127/njgpm/1998/1998/604.
^ abSmall, B.J. (1998). "The occurrence of Aetosaurus in the Chinle Formation (Late Triassic, USA) and its biostratigraphic significance". Neues Jahrbuch für Geologie und Paläontologie. 1998 (3): 289–300.
^ abJenkins, F.A. Jr.; Shubin, N.H.; Amaral, W.W.; Gatesy, S.M.; Schaff, C.R.; Clemmensen, L.B.; Downs, W.R.; Davidson, A.R.; Bonde, N.; Osbaeck, F.F. (1994). "Late Triassic continental vertebrates and depositional environments of the Fleming Fjord Formation, Jameson Land, East Greenland". Meddelelser om Grønland, Geoscience. 32: 1–25.
^Teschner, Elżbieta M.; Konietzko-Meier, Dorota; Desojo, Julia B.; Schoch, Rainer R.; Klein, Nicole (2023-02-12). "Triassic Nursery? Evidence of gregarious behavior in juvenile pseudosuchian archosaurs as inferred by humeral histology of Aetosaurus ferratus (Norian; southern Germany)". Journal of Vertebrate Paleontology. 42 (2): e2168196. doi:10.1080/02724634.2023.2168196. ISSN 0272-4634. S2CID 256864004.
^Lazaro, Enrico de (2023-02-13). "Aetosaurs Were Gregarious, Paleontologists Say | Sci.News". Sci.News: Breaking Science News. Retrieved 2023-02-14.
^Wild, R. (1989). "Aëtosaurus (Reptilia:Thecodontia) from the Upper Triassic (Norian) of Cene near Bergamo, Italy, with a revision of the genus" (PDF). Revista del Museo Civico di Scienze Naturali "Enrico Caffi". 14: 1–24.
^Marsh, O.C. (1896). "A new belodont reptile (Stegomus) from the Connecticut River Sandstone". American Journal of Science. 2 (7): 59–62. Bibcode:1896AmJS....2...59M. doi:10.2475/ajs.s4-2.7.59.
^Jepsen, G.L. (1948). "A Triassic armored reptile from New Jersey". State of New Jersey Department of Conservation Miscellaneous Geological Paper: 1–20.
^Baird, D. (1986). "Some Upper Triassic reptiles, footprints and an amphibian from New Jersey". The Mosasaur. 3: 125–135.
^Parker, J.M. (1966). "Triassic reptilian fossil from Wake County, North Carolina". Journal of the Elisha Mitchell Society. 82: 92.
^Lull, R.S. (1953). "Triassic life of the Connecticut Valley revised". Bulletin of the Connecticut Geologic and Natural History Survey. 81: 1–336.
^Julia B. Desojo, Martin D. Ezcurra and Edio E. Kischlat (2012). "A new aetosaur genus (Archosauria: Pseudosuchia) from the early Late Triassic of southern Brazil" (PDF). Zootaxa. 3166: 1–33. doi:10.11646/zootaxa.3166.1.1. ISSN 1175-5334.
aetosaurus, extinct, genus, pseudosuchian, reptile, belonging, order, aetosauria, generally, considered, most, primitive, aetosaur, three, species, currently, recognized, ferratus, type, species, from, germany, italy, crassicauda, from, germany, arcuatus, from. Aetosaurus is an extinct genus of pseudosuchian reptile belonging to the order Aetosauria It is generally considered to be the most primitive aetosaur 1 Three species are currently recognized A ferratus the type species from Germany and Italy 2 A crassicauda from Germany 3 and A arcuatus from eastern North America 4 Additional specimens referred to Aetosaurus have been found in the Chinle Group of the southwestern United States 5 6 and the Fleming Fjord Formation of Greenland 7 Specimens of Aetosaurus occur in Norian age strata AetosaurusTemporal range Late Triassic Carnian Norian PreꞒ Ꞓ O S D C P T J K Pg NAssemblage of fossil A ferratusScientific classificationDomain EukaryotaKingdom AnimaliaPhylum ChordataClass ReptiliaClade ArchosauriaClade PseudosuchiaOrder AetosauriaFamily StagonolepididaeSubfamily AetosaurinaeGenus AetosaurusFraas 1887Species A arcuatus Marsh 1896 A crassicauda Fraas 1907 A ferratus Fraas 1877 type SynonymsStegomus arcuatus Marsh 1896 Contents 1 Description 2 Behaviour 3 Species 4 References 5 External linksDescription editAetosaurus was a small primitive aetosaur Unlike more derived aetosaurs such as Desmatosuchus or Typothorax the carapace was long and narrow and lacked spikes The paramedian scutes that covered the back with one row on each side of the vertebrae are considerably wider than they are long The lateral scutes which are beneath the paramedian and formed a row on either side of the animal do not bear any spikes or other projections 4 Behaviour editA 2023 study based on a fossil assemblage found in Kaltental suggested that juvenile A ferratus were likely gregarious animals possibly to increase their chances of survival and to deter predators 8 9 Species edit nbsp Reconstructed skull of A ferratusAetosaurus was first named with the description of the type species A ferratus in 1877 by German paleontologist Oscar Fraas At the time Aetosaurus was known from 22 articulated skeletons that had been found in the Lower Stubensandtein of Germany 2 Thirty years later Fraas son Eberhard described a second species A crassicauda also from Germany 3 A crassicauda can be distinguished from A ferratus by its larger size A crassicauda reached a maximum length of 150 centimetres 59 in while A ferratus reached a length of up to 90 centimetres 35 in 1 In addition to the Stubensandtein in Germany A ferratus is also known from the Calcare di Zorzino Formation in Cene Italy 10 Specimens of Aetosaurus that have been recovered from the Fleming Fjord Formation in Greenland likely represent A ferratus 7 Some material from the Chinle Group in the southwestern United States probably represent A ferratus as well 5 6 In 1998 the genus Stegomus was synonymized with Aetosaurus 4 In 1896 paleontologist Othniel Charles Marsh named Stegomus arcuatus from a cast of an aetosaur known as YPM 1647 from the New Haven Formation in the Fair Haven Heights neighborhood of New Haven 11 This cast consisted of the dorsal carapace Several other casts preserving the surface of the skull and tail have been found in the Passaic Formation of Hunterdon and Somerset counties New Jersey 12 13 and an outcrop of the Lower Sanford Formation at the Triangle Brick Co Quarry in Durham County North Carolina 14 Stegomus arcuatus was found to be synonymous with Aetosaurus on the basis of several similarities including a lack of spikes and a distinctive radial pattern of grooves on some of the caudal scutes 4 nbsp Photograph of YPM 1647 a specimen of A arcuatus nbsp Skeletal drawing of A ferratus by MarshA arcuatus has paramedian scutes that are much wider than they are long even in comparison to other species of Aetosaurus There is very little pitting on the surface of the scutes although the porosity of the sandstone that makes up the casts has been mistaken for pitting 15 The tail narrows significantly past the base The carapace is waisted meaning that it narrows in front of the pelvis 4 The following cladogram is simplified after an analysis presented by Julia B Desojo Martin D Ezcurra and Edio E Kischlat 2012 16 Aetosauria Aetosauroides scagliai Stagonolepididae Aetosaurus ferratusCoahomasuchus kahleorumNeoaetosauroides engaeusCalyptosuchus wellesiStagonolepis robertsoniAetobarbakinoides brasiliensis Typothoracisinae TypothoraxRedondasuchus Paratypothoracisini Tecovasuchus chatterjeeiRioarribasuchus chamaensisParatypothorax andressorum Desmatosuchinae Sierritasuchus macalpiniLongosuchus meadeiLucasuchus huntiAcaenasuchus geoffreyi Desmatosuchus Desmatosuchus haplocerusDesmatosuchus smalliReferences edit a b Heckert A B Lucas S G 1999 A new aetosaur Reptilia Archosauria from the Upper Triassic of Texas and the phylogeny of aetosaurs Journal of Vertebrate Paleontology 19 1 50 68 Bibcode 1999JVPal 19 50H CiteSeerX 10 1 1 563 9516 doi 10 1080 02724634 1999 10011122 a b Fraas O 1877 Aetosaurus ferratus Fr Die gepanzerte Vogel Echse aus dem Stubensandstein bei Stuttgar Festschrift zur Feier des 400jahrigen Jubilaums der Eberhard Karls Universat zu Tubingen Wurttembergische Naturwissenschaftliche Jahreshefte 33 3 1 22 a b Fraas E 1907 Aetosaurus crassicauda n sp nebst Beobachtungen tiber das Becken der Aetosaurier Jahreshefte des Vereins fur Vaterlandische Naturkunde Wurttemberg 42 101 109 a b c d e Lucas S G Heckert A B Huber P 1998 Aetosaurus Archosauromorpha from the Upper Triassic of the Newark Supergroup eastern United States and its biochronological significance PDF Palaeontology 41 6 1215 1230 Archived from the original PDF on 2012 03 09 a b Heckert A B Lucas S G 1998 First occurrence of Aetosaurus Reptilia Archosauria in the Upper Triassic Chinle Group USA and its biochronological significance Neues Jahrbuch fur Geologie und Palaontologie 1998 10 604 612 doi 10 1127 njgpm 1998 1998 604 a b Small B J 1998 The occurrence of Aetosaurus in the Chinle Formation Late Triassic USA and its biostratigraphic significance Neues Jahrbuch fur Geologie und Palaontologie 1998 3 289 300 a b Jenkins F A Jr Shubin N H Amaral W W Gatesy S M Schaff C R Clemmensen L B Downs W R Davidson A R Bonde N Osbaeck F F 1994 Late Triassic continental vertebrates and depositional environments of the Fleming Fjord Formation Jameson Land East Greenland Meddelelser om Gronland Geoscience 32 1 25 Teschner Elzbieta M Konietzko Meier Dorota Desojo Julia B Schoch Rainer R Klein Nicole 2023 02 12 Triassic Nursery Evidence of gregarious behavior in juvenile pseudosuchian archosaurs as inferred by humeral histology of Aetosaurus ferratus Norian southern Germany Journal of Vertebrate Paleontology 42 2 e2168196 doi 10 1080 02724634 2023 2168196 ISSN 0272 4634 S2CID 256864004 Lazaro Enrico de 2023 02 13 Aetosaurs Were Gregarious Paleontologists Say Sci News Sci News Breaking Science News Retrieved 2023 02 14 Wild R 1989 Aetosaurus Reptilia Thecodontia from the Upper Triassic Norian of Cene near Bergamo Italy with a revision of the genus PDF Revista del Museo Civico di Scienze Naturali Enrico Caffi 14 1 24 Marsh O C 1896 A new belodont reptile Stegomus from the Connecticut River Sandstone American Journal of Science 2 7 59 62 Bibcode 1896AmJS 2 59M doi 10 2475 ajs s4 2 7 59 Jepsen G L 1948 A Triassic armored reptile from New Jersey State of New Jersey Department of Conservation Miscellaneous Geological Paper 1 20 Baird D 1986 Some Upper Triassic reptiles footprints and an amphibian from New Jersey The Mosasaur 3 125 135 Parker J M 1966 Triassic reptilian fossil from Wake County North Carolina Journal of the Elisha Mitchell Society 82 92 Lull R S 1953 Triassic life of the Connecticut Valley revised Bulletin of the Connecticut Geologic and Natural History Survey 81 1 336 Julia B Desojo Martin D Ezcurra and Edio E Kischlat 2012 A new aetosaur genus Archosauria Pseudosuchia from the early Late Triassic of southern Brazil PDF Zootaxa 3166 1 33 doi 10 11646 zootaxa 3166 1 1 ISSN 1175 5334 External links editAetosaurus in the Paleobiology Database nbsp Paleontology portal Retrieved from https en wikipedia org w index php title Aetosaurus amp oldid 1165816179, wikipedia, wiki, book, books, library,
