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Pistosaurus

April 12, 2024

Pistosaurus (pistos in Greek meaning 'credible' and sauros 'lizard'[1]) is an extinct genus of aquatic sauropterygian reptile closely related to plesiosaurs. Fossils have been found in France and Germany, and date to the Middle Triassic. It contains a single species, Pistosaurus longaevus. Pistosaurus is known as the oldest "subaquatic flying" reptile on earth.

Pistosaurus
Temporal range: Middle Triassic, Anisian–Ladinian
Fossil
Scientific classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Superorder: †Sauropterygia
Family: †Pistosauridae
Zittel, 1887
Genus: †Pistosaurus
Meyer, 1839
Type species
†Pistosaurus longaevus
Meyer, 1839
Pistosaurus longaevus skull (cast)

The skull of Pistosaurus generally resembles that of other Triassic sauropterygians. However, there are several synapomorphies that make Pistosaurus distinguished: the long, slender, snout; the possession of splint-like nasals that are excluded from the external naris; and the posterior extension of the premaxilla to the frontals.[2] Based on synapomorphies such as the small nasals size and the presence of interpterygoid vacuity, Pistosaurus is more closely related to Plesiosauria than to Nothosaurus.[2]

Pistosaurus is often mistaken with Nothosaurus and Plesiosauria. Nothosaurus belongs to the clade Nothosauroidea from the middle Triassic (approximately 199-251 million years ago); while Pistosaurus belongs to stem group Plesiosauria; and both Pistosaurus and Plesiosauria belongs to clade Pistosauroidea from Triassic. Both Nothosauroidea and Pistosauroidea belong to Sauropterygia.[2]

Description and paleobiology edit

 
Restoration of Pistosaurus longaevus

Pistosaurus was about 3 metres (10 ft) long, and had a body form resembling that of nothosaurs, aquatic reptiles that flourished during the Triassic. However, the vertebral column was stiff, like that of a plesiosaur, implying that the animal used its paddle-like flippers to propel itself through the water, as the plesiosaurs probably did. The head also resembled that of a plesiosaur, but with the primitive palate of a nothosaur, and numerous, sharp teeth ideal for catching and eating fish.[3]

Post-cranial skeleton edit

The description below is based on the specimen examined by paleontologist Sues in 1987.

Pectoral girdle and forelimbs edit

The structure of pectoral girdle and humerus are used to support the anterior part of the body.[4] The scapula in pectoral girdle of Pistosaurus consists with a massive body and a short posterodorsal process. It is smaller in size compared to coracoid. And its lateral margin of the body is gently convex anteroposteriorly while the medial margin is more strongly convex.[4]

The coracoid bone of Pistosaurus is flat and expanded medially.[4] The glenoid region is similar to Nothosaurus in development: both the slight notching of its margin and a distinct facet contact with the humeral head. There is also a ridge like thickening which links the glenoid to posteromedial region of the coracoid.[4] This feature is a synapomorphy that appears in plesiosaurs, which is a thickened ridge passes transversely across the anterior portion of the coracoid to connect the glenoid region. This feature is suggested related to compressional force by limb motion in Pistosaurus.[4]

A specimen of the left humerus of Pistosaurus analyzed by Paleontologist A.R.I. Cruickshank is one of the largest specimens recorded: 245mm long and 45mm wide at the mid-shaft.[5] The specimen showing that the axis of Pistosaurus' humerus is straight, with the distal end slightly expanded posteriorly.[5] From proximal view, the head of the humerus is concave, which is a sign of a substantial cap of cartilage at the head of humerus. The humerus of Pistosaurus also lacks entepicondylar foramen.[5]

Pistosaurus has a strongly flattened ulna. It has medium length and nearly symmetrical in dorsal view.[4] Its anterior margin is more curved and thicker than the posterior one. This feature broads the wide spatium interosseum enclosed between radius and ulna.[4] The proximal end of radius is less expanded than that of ulna, while the distal end is less expanded than proximal one but thickened.[4] The anterior margin is nearly straight while the posterior margin is more curved compared to the anterior one. Like other sauropterygians, the radius of Pistosaurus is slightly longer than the ulna.[4]

Pelvic girdle edit

The pelvic girdle of Pistosaurus is more similar to primitive sauropterygians than to plesiosaurs.

The ilium of Pistosaurus has an iliac blade, which has almost parallel anterior and posterior margins.[4] Same as other non-plesiosaur sauropterygians, the ilium in Pistosaurus contacts both the pubis and the ischium, forming a ring-like structure. The ilium from Pistosaurus is relatively large in size compared to Nothosaurus, whose ilia did not appear to have any elongated blade.[4]

The femur of Pistosaurus is longer than its humerus. Its anterior margin is almost straight whereas the posterior margin is concave.[4] According to the specimen provided by paleontologist Sues, the proximal articular end is much more robust than the distal one, and is more or less triangular in transverse section.[4]

Classification edit

 
Limb bone

Although it is unlikely that Pistosaurus was a direct ancestor of the plesiosaurs, the mixture of features suggests that it was closely related to that group.[3]

The following cladogram follows an analysis by Ketchum & Benson, 2011.[6]

The classification for Plesiosauria was difficult at the first place. The anatomy of stem group Sauropterygia has very primitive synapomorphies such as dermal palate. Initially, Plesiosauria were suggested related to Pistosauroidea, which belongs to Eusauropterygia from Triassic. Three genera of Plesiosauria was known in the history: Corosaurus alvocensis, Cymatosaurus, and Pistosaurus longaevus.[7] A later discovery of a new Pistosauridea from middle triassic of Nevada by paleontologist Sander indicates that Augustasaurus is closely related to Pistosaurus, while there are several difference including axial skeleton.[8]

Geological environment information edit

There are several different ways for aquatic tetrapods to counteract their positive buoyancy caused by their lungs: pachyostosis, osteosclerosis, pachyosteosclerosis, and calcified cartilage of bone. The ultimate goal of these processes are to increase density for different parts of the body to offset the buoyancy, in order to live in an aquatic/semi-aquatic environment.[2] Bone histology of Pistosaurus longaevus studied by Paleontologist Krahl showed that the medullary region of humeri was filled, and it contained calcified cartilage incorporated into endoseal bone. According to Krahl, the small region of medullary of humeri is results from a suppressed perimedullary resorption activity, which is associated with osteosclerosis.[2]

Paleontologist Diedrich examined other pectoral and pelvic girdle of Pistosaurus. Together with the muscle grooves, they determined that a slight subaquatic flying starts with Pistosaurus. And most of the propulsion occurs on the hindlimbs. The presence of enlarged coracoid and pubis bone in pelvic girdle indicated that there were possibility for Pistosaurus to develop flipper-like extremities.[9] What's more, the underwater flying mode suggested by paleontologist Michael. A. Taylor indicates that the left and right limb of Plesiosaurus would simultaneously beat together. This feature contrasts to the terrestrial reptile who use right and left limbs for locomotion alternatively.[10]

Historical information and discovery edit

The non-Plesiosaurian Sauropterygians are found in various locations in China, Europe, America, Palestine and Tunisia. Although Nothosaurus, which is closely related to Pistosaurus, are found plenty across Europe, Pistosaurus skull is only found in Germanic basin in Upper Muschelkalk.[2]

The early discovery of Pistosaurus skull was by H. v. Meyer. He discovered two skulls and a postcranial skeleton at the same location, possibly from Pistosaurus. Later after that, a new and well preserved postcranial skeleton was also found at the same location as previous specimens.[11] Paleontologist Geissler first described the skeletons and then paleontologist Strunz developed new hypothesis based on that. This skeleton was originally preserved at Strunz collection in Senckenberg Museum at Frankfurt a/M.[11]

Although Pistosauroidea has long been considered as structural antecedents of Plesiosauria, a new specimen of Augustasaurus discovered by paleontologist Sandra from Nevada had raised to against this theory. Opposed to previous hypothesis, the forelimb of Augustasaurus was greatly reduced compared to Plesiosaurus. Therefore, Pistosauroidea was removed from stem group Plesiosauria and becomes paraphyletic group to Plesiosauria.[8]

Avascular necrosis, also known as bone necrosis, is associated with decompression syndrome (DCS). It is caused by expose rapid decrease of external pressure as well as rapid ascent in water column.[12] There features are often recognized in Triassic Sauropterygians. According to paleontologist Surmik, the presence of decompression syndrome-related avascular necrosis in Pistosaurus forelimb suggested that Pistosaurus used to live in aquatic or semi-aquatic environment. He also stated the possibility of Pistosaurus distributed in open marine cold water, and their effective metabolism is one of the reasons why Pistosaurus can survive the open sea.[12]

References edit

  1. ^ Creisler, Ben (1 April 2015). . Archived from the original on 6 August 2016.
  2. ^ a b c d e f Krahl, Anna; Klein, Nicole & Sander, P. Martin (2013). "Evolutionary Implications of the Divergent Long Bone Histologies of Nothosaurus and Pistosaurus (Sauropterygia, Triassic)". BMC Evolutionary Biology. 13 (1): 123. Bibcode:2013BMCEE..13..123K. doi:10.1186/1471-2148-13-123. PMC 3694513. PMID 23773234.
  3. ^ a b Palmer, Douglas, ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. p. 73. ISBN 1-84028-152-9.
  4. ^ a b c d e f g h i j k l m Sues, H.-D. (1987). "Postcranial Skeleton of Pistosaurus and Interrelationships of the Sauropterygia (Diapsida)". Zoological Journal of the Linnean Society. 90 (2): 109–131. doi:10.1111/j.1096-3642.1987.tb01351.x.
  5. ^ a b c Cruickshank, A. (1996). "A Pistosaurus-like Sauropterygian from the Rhaeto-Hettangian of England". Mercian Geologist. 14 (1): 12–13.
  6. ^ Ketchum, Hilary F. & Benson, Roger B. J. (2011). "A new pliosaurid (Sauropterygia, Plesiosauria) from the Oxford Clay Formation (Middle Jurassic, Callovian) of England: evidence for a gracile, longirostrine grade of Early-Middle Jurassic pliosaurids". Special Papers in Palaeontology. 86: 109–129.
  7. ^ Rieppel, Olivier; Sander, P. Martin & Storrs, Glenn W. (2002). "The Skull of the Pistosaur Augustasaurus from the Middle Triassic of Northwestern Nevada". Journal of Vertebrate Paleontology. 22 (3): 577–592. doi:10.1671/0272-4634(2002)022[0577:TSOTPA]2.0.CO;2. S2CID 131693849.
  8. ^ a b Sander, P. Martin; Rieppel, Olivier C. & Bucher, Hugo (1997). "A New Pistosaurid (Reptilia: Sauropterygia) from the Middle Triassic of Nevada and Its Implications for the Origin of the Plesiosaurs". Journal of Vertebrate Paleontology. 17 (3): 526–533. Bibcode:1997JVPal..17..526S. doi:10.1080/02724634.1997.10010999.
  9. ^ Diedrich, Cajus G. (2013). "The Oldest "Subaquatic Flying" Reptile in the World; Pistosaurus Longaevus Meyer, 1839 (Sauropterygia) from the Middle Triassic of Europe". In Lawrence H. Tanner; Justin A. Spielmann & Spencer G. Lucas (eds.). The Triassic System: New Developments in Stratigraphy and Paleontology. Vol. Bulletin 61. Albuquerque: New Mexico Museum of Natural History and Science. pp. 169–215.
  10. ^ Taylor, Michael A. (1989). "Palaeontology; Sea-Saurians for Sceptics". Nature. 338 (6217). London: 625–626. doi:10.1038/338625a0. S2CID 4325199.
  11. ^ a b Huene, Friedrich von (1948). "Pistosaurus, a Middle Triassic Plesiosaur". American Journal of Science. 246 (1): 46–52. Bibcode:1948AmJS..246...46H. doi:10.2475/ajs.246.1.46.
  12. ^ a b Surmik, Dawid; Rothschild, Bruce M.; Dulski, Mateusz & Janiszewska, Katarzyna (2017). "Two Types of Bone Necrosis in the Middle Triassic Pistosaurus Longaevus Bones: the Results of Integrated Studies". Royal Society Open Science. 4 (7): 170204. Bibcode:2017RSOS....470204S. doi:10.1098/rsos.170204. PMC 5541542. PMID 28791147.

April 12, 2024
pistosaurus, pistos, greek, meaning, credible, sauros, lizard, extinct, genus, aquatic, sauropterygian, reptile, closely, related, plesiosaurs, fossils, have, been, found, france, germany, date, middle, triassic, contains, single, species, longaevus, known, ol. Pistosaurus pistos in Greek meaning credible and sauros lizard 1 is an extinct genus of aquatic sauropterygian reptile closely related to plesiosaurs Fossils have been found in France and Germany and date to the Middle Triassic It contains a single species Pistosaurus longaevus Pistosaurus is known as the oldest subaquatic flying reptile on earth PistosaurusTemporal range Middle Triassic Anisian Ladinian PreꞒ Ꞓ O S D C P T J K Pg NFossilScientific classificationDomain EukaryotaKingdom AnimaliaPhylum ChordataClass ReptiliaSuperorder SauropterygiaFamily PistosauridaeZittel 1887Genus PistosaurusMeyer 1839Type species Pistosaurus longaevusMeyer 1839Pistosaurus longaevus skull cast The skull of Pistosaurus generally resembles that of other Triassic sauropterygians However there are several synapomorphies that make Pistosaurus distinguished the long slender snout the possession of splint like nasals that are excluded from the external naris and the posterior extension of the premaxilla to the frontals 2 Based on synapomorphies such as the small nasals size and the presence of interpterygoid vacuity Pistosaurus is more closely related to Plesiosauria than to Nothosaurus 2 Pistosaurus is often mistaken with Nothosaurus and Plesiosauria Nothosaurus belongs to the clade Nothosauroidea from the middle Triassic approximately 199 251 million years ago while Pistosaurus belongs to stem group Plesiosauria and both Pistosaurus and Plesiosauria belongs to clade Pistosauroidea from Triassic Both Nothosauroidea and Pistosauroidea belong to Sauropterygia 2 Contents 1 Description and paleobiology 1 1 Post cranial skeleton 1 1 1 Pectoral girdle and forelimbs 1 1 2 Pelvic girdle 2 Classification 3 Geological environment information 4 Historical information and discovery 5 ReferencesDescription and paleobiology edit nbsp Restoration of Pistosaurus longaevusPistosaurus was about 3 metres 10 ft long and had a body form resembling that of nothosaurs aquatic reptiles that flourished during the Triassic However the vertebral column was stiff like that of a plesiosaur implying that the animal used its paddle like flippers to propel itself through the water as the plesiosaurs probably did The head also resembled that of a plesiosaur but with the primitive palate of a nothosaur and numerous sharp teeth ideal for catching and eating fish 3 Post cranial skeleton edit The description below is based on the specimen examined by paleontologist Sues in 1987 Pectoral girdle and forelimbs edit The structure of pectoral girdle and humerus are used to support the anterior part of the body 4 The scapula in pectoral girdle of Pistosaurus consists with a massive body and a short posterodorsal process It is smaller in size compared to coracoid And its lateral margin of the body is gently convex anteroposteriorly while the medial margin is more strongly convex 4 The coracoid bone of Pistosaurus is flat and expanded medially 4 The glenoid region is similar to Nothosaurus in development both the slight notching of its margin and a distinct facet contact with the humeral head There is also a ridge like thickening which links the glenoid to posteromedial region of the coracoid 4 This feature is a synapomorphy that appears in plesiosaurs which is a thickened ridge passes transversely across the anterior portion of the coracoid to connect the glenoid region This feature is suggested related to compressional force by limb motion in Pistosaurus 4 A specimen of the left humerus of Pistosaurus analyzed by Paleontologist A R I Cruickshank is one of the largest specimens recorded 245mm long and 45mm wide at the mid shaft 5 The specimen showing that the axis of Pistosaurus humerus is straight with the distal end slightly expanded posteriorly 5 From proximal view the head of the humerus is concave which is a sign of a substantial cap of cartilage at the head of humerus The humerus of Pistosaurus also lacks entepicondylar foramen 5 Pistosaurus has a strongly flattened ulna It has medium length and nearly symmetrical in dorsal view 4 Its anterior margin is more curved and thicker than the posterior one This feature broads the wide spatium interosseum enclosed between radius and ulna 4 The proximal end of radius is less expanded than that of ulna while the distal end is less expanded than proximal one but thickened 4 The anterior margin is nearly straight while the posterior margin is more curved compared to the anterior one Like other sauropterygians the radius of Pistosaurus is slightly longer than the ulna 4 Pelvic girdle edit The pelvic girdle of Pistosaurus is more similar to primitive sauropterygians than to plesiosaurs The ilium of Pistosaurus has an iliac blade which has almost parallel anterior and posterior margins 4 Same as other non plesiosaur sauropterygians the ilium in Pistosaurus contacts both the pubis and the ischium forming a ring like structure The ilium from Pistosaurus is relatively large in size compared to Nothosaurus whose ilia did not appear to have any elongated blade 4 The femur of Pistosaurus is longer than its humerus Its anterior margin is almost straight whereas the posterior margin is concave 4 According to the specimen provided by paleontologist Sues the proximal articular end is much more robust than the distal one and is more or less triangular in transverse section 4 Classification edit nbsp Limb boneAlthough it is unlikely that Pistosaurus was a direct ancestor of the plesiosaurs the mixture of features suggests that it was closely related to that group 3 The following cladogram follows an analysis by Ketchum amp Benson 2011 6 The classification for Plesiosauria was difficult at the first place The anatomy of stem group Sauropterygia has very primitive synapomorphies such as dermal palate Initially Plesiosauria were suggested related to Pistosauroidea which belongs to Eusauropterygia from Triassic Three genera of Plesiosauria was known in the history Corosaurus alvocensis Cymatosaurus and Pistosaurus longaevus 7 A later discovery of a new Pistosauridea from middle triassic of Nevada by paleontologist Sander indicates that Augustasaurus is closely related to Pistosaurus while there are several difference including axial skeleton 8 Pistosauria Pistosaurus postcranium Augustasaurus hagdorniBobosaurus forojuliensisPistosaurusYunguisaurus liae Plesiosauria Pliosauroidea Pliosauridae Thalassiodracon hawkinsiiHauffiosaurus spp Attenborosaurus conybeariadvanced pliosaurids Rhomaleosauridae Anningasaura lymenseadvanced rhomaleosaurids Plesiosaurus macrocephalusArchaeonectrus rostratusMacroplata tenuiceps Plesiosauroidea Stratesaurus taylori Plesiosauridae Seeleyosaurus guilelmiimperatorisOUMNH J 28585Plesiosaurus dolichodeirusElasmosauridae and CryptoclidiaMicrocleidus homalospondylusHydrorion brachypterygiusOccitanosaurus tournemiensis Geological environment information edit There are several different ways for aquatic tetrapods to counteract their positive buoyancy caused by their lungs pachyostosis osteosclerosis pachyosteosclerosis and calcified cartilage of bone The ultimate goal of these processes are to increase density for different parts of the body to offset the buoyancy in order to live in an aquatic semi aquatic environment 2 Bone histology of Pistosaurus longaevus studied by Paleontologist Krahl showed that the medullary region of humeri was filled and it contained calcified cartilage incorporated into endoseal bone According to Krahl the small region of medullary of humeri is results from a suppressed perimedullary resorption activity which is associated with osteosclerosis 2 Paleontologist Diedrich examined other pectoral and pelvic girdle of Pistosaurus Together with the muscle grooves they determined that a slight subaquatic flying starts with Pistosaurus And most of the propulsion occurs on the hindlimbs The presence of enlarged coracoid and pubis bone in pelvic girdle indicated that there were possibility for Pistosaurus to develop flipper like extremities 9 What s more the underwater flying mode suggested by paleontologist Michael A Taylor indicates that the left and right limb of Plesiosaurus would simultaneously beat together This feature contrasts to the terrestrial reptile who use right and left limbs for locomotion alternatively 10 Historical information and discovery edit The non Plesiosaurian Sauropterygians are found in various locations in China Europe America Palestine and Tunisia Although Nothosaurus which is closely related to Pistosaurus are found plenty across Europe Pistosaurus skull is only found in Germanic basin in Upper Muschelkalk 2 The early discovery of Pistosaurus skull was by H v Meyer He discovered two skulls and a postcranial skeleton at the same location possibly from Pistosaurus Later after that a new and well preserved postcranial skeleton was also found at the same location as previous specimens 11 Paleontologist Geissler first described the skeletons and then paleontologist Strunz developed new hypothesis based on that This skeleton was originally preserved at Strunz collection in Senckenberg Museum at Frankfurt a M 11 Although Pistosauroidea has long been considered as structural antecedents of Plesiosauria a new specimen of Augustasaurus discovered by paleontologist Sandra from Nevada had raised to against this theory Opposed to previous hypothesis the forelimb of Augustasaurus was greatly reduced compared to Plesiosaurus Therefore Pistosauroidea was removed from stem group Plesiosauria and becomes paraphyletic group to Plesiosauria 8 Avascular necrosis also known as bone necrosis is associated with decompression syndrome DCS It is caused by expose rapid decrease of external pressure as well as rapid ascent in water column 12 There features are often recognized in Triassic Sauropterygians According to paleontologist Surmik the presence of decompression syndrome related avascular necrosis in Pistosaurus forelimb suggested that Pistosaurus used to live in aquatic or semi aquatic environment He also stated the possibility of Pistosaurus distributed in open marine cold water and their effective metabolism is one of the reasons why Pistosaurus can survive the open sea 12 References edit Creisler Ben 1 April 2015 The Joke Names Oromys Leidy 1853 and Pistosaurus von Meyer 1839 Archived from the original on 6 August 2016 a b c d e f Krahl Anna Klein Nicole amp Sander P Martin 2013 Evolutionary Implications of the Divergent Long Bone Histologies of Nothosaurus and Pistosaurus Sauropterygia Triassic BMC Evolutionary Biology 13 1 123 Bibcode 2013BMCEE 13 123K doi 10 1186 1471 2148 13 123 PMC 3694513 PMID 23773234 a b Palmer Douglas ed 1999 The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals London Marshall Editions p 73 ISBN 1 84028 152 9 a b c d e f g h i j k l m Sues H D 1987 Postcranial Skeleton of Pistosaurus and Interrelationships of the Sauropterygia Diapsida Zoological Journal of the Linnean Society 90 2 109 131 doi 10 1111 j 1096 3642 1987 tb01351 x a b c Cruickshank A 1996 A Pistosaurus like Sauropterygian from the Rhaeto Hettangian of England Mercian Geologist 14 1 12 13 Ketchum Hilary F amp Benson Roger B J 2011 A new pliosaurid Sauropterygia Plesiosauria from the Oxford Clay Formation Middle Jurassic Callovian of England evidence for a gracile longirostrine grade of Early Middle Jurassic pliosaurids Special Papers in Palaeontology 86 109 129 Rieppel Olivier Sander P Martin amp Storrs Glenn W 2002 The Skull of the Pistosaur Augustasaurus from the Middle Triassic of Northwestern Nevada Journal of Vertebrate Paleontology 22 3 577 592 doi 10 1671 0272 4634 2002 022 0577 TSOTPA 2 0 CO 2 S2CID 131693849 a b Sander P Martin Rieppel Olivier C amp Bucher Hugo 1997 A New Pistosaurid Reptilia Sauropterygia from the Middle Triassic of Nevada and Its Implications for the Origin of the Plesiosaurs Journal of Vertebrate Paleontology 17 3 526 533 Bibcode 1997JVPal 17 526S doi 10 1080 02724634 1997 10010999 Diedrich Cajus G 2013 The Oldest Subaquatic Flying Reptile in the World Pistosaurus Longaevus Meyer 1839 Sauropterygia from the Middle Triassic of Europe In Lawrence H Tanner Justin A Spielmann amp Spencer G Lucas eds The Triassic System New Developments in Stratigraphy and Paleontology Vol Bulletin 61 Albuquerque New Mexico Museum of Natural History and Science pp 169 215 Taylor Michael A 1989 Palaeontology Sea Saurians for Sceptics Nature 338 6217 London 625 626 doi 10 1038 338625a0 S2CID 4325199 a b Huene Friedrich von 1948 Pistosaurus a Middle Triassic Plesiosaur American Journal of Science 246 1 46 52 Bibcode 1948AmJS 246 46H doi 10 2475 ajs 246 1 46 a b Surmik Dawid Rothschild Bruce M Dulski Mateusz amp Janiszewska Katarzyna 2017 Two Types of Bone Necrosis in the Middle Triassic Pistosaurus Longaevus Bones the Results of Integrated Studies Royal Society Open Science 4 7 170204 Bibcode 2017RSOS 470204S doi 10 1098 rsos 170204 PMC 5541542 PMID 28791147 nbsp Paleontology portal Retrieved from https en wikipedia org w index php title Pistosaurus amp oldid 1209754884, wikipedia, wiki, book, books, library,

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