Pawpawsaurus was found in the Paw Paw Formation in Tarrant County, Texas, in May 1992, by Cameron Campbell. A complete skull is the only specimen, from which the binomial was named Pawpawsaurus campbelli. The Paw Paw Formation has produced another nodosaurid, Texasetes pleurohalio (Coombs, 1995), which may prove to be a senior synonym of Pawpawsaurus. This is the only nodosaurid known to have possessed the bony eyelids commonly found in ankylosaurids. The skull of Pawpawsaurus bears some notable similarities to that of Silvisaurus, such as the presence of teeth in the premaxilla and the restriction of the osseoussecondary palate to the rostral portion of the palatal region.[1]
Descriptionedit
Skull cast in front view
Pawpawsaurus was a medium-sized nodosaur measuring 4.5 metres (15 ft) long.[2] It is known from a relatively well preserved and complete skull. The skull is complete enough for a 2016 study to be able to identify and reconstruct the brain, nasal cavities and inner ear of the specimen, and CT scan it to find new anatomical features.[3]
The brain of Pawpawsaurus is very similar to other ankylosaurians, but along with more derived taxa it is most different from Kunbarrasaurus. The brain is 30% of the skull length, very similar to Panoplosaurus, higher than Euoplocephalus, and lower than Kunbarrasaurus. The brain of Pawpawsaurus is 96 millimetres (3.8 in) long and 35 millimetres (1.4 in) wide. The inner ear is also similar to ankylosaurians to the exclusion of Kunbarrasaurus, being 27 millimetres (1.1 in) tall and 15.5 millimetres (0.61 in) wide at the level of the semicircular canals. The nasal cavities of Pawpawsaurus resemble that of Panoplosaurus and Euoplocephalus, although the thin dividing medians are not preserved as they were likely cartilaginous.[3]
Classificationedit
Vickaryous et al. (2004) have stated that "Sauropelta edwardsorum, Silvisaurus condrayi, and Pawpawsaurus campbelli form a basal polytomy nested deep to Cedarpelta."[4] Alternatively, Pawpawsaurus has been identified as a relative of Struthiosaurus, with cladogram below showing the results of the 2018 phylogenetic analysis of Rivera-Sylva and colleagues, resolving Pawpawsaurus within the clade Struthiosaurini as labelled by Madzia et al., with relationships outside Struthiosaurini excluded for simplicity.[5][6]
However, the strict consensus tree of a phylogenetic analysis performed by Brown et al. (2017) placed Pawpawsaurus in a clade with Borealopelta markmitchelli and Europelta carbonensis. The results of the strict consensus are displayed in the phylogeny below, with taxa outside Nodosauridae being excluded.[7]
Pawpawsaurus was primitive in regards to its sensory abilities when compared to later ankylosaurs. CT scans of its skull and brain by Paulina-Carabajal and Louis Jacobs et al. revealed that Pawpawsaurus' hearing was on par with that of modern crocodilians, indicating that its hearing was relatively poor. Its sense of smell meanwhile, while not as advanced as that of later ankylosaurs, was still more powerful and acute than many of the theropods existent at the time thanks to its large nasal cavities. The enlarged nasal cavities of Pawpawsaurus would also likely have been useful for cooling blood that was entering the brain, finding food and potential mates, or alerting it to danger.[8]
^ abLee, Y.N. (1996). "A new nodosaurid ankylosaur (Dinosauria: Ornithischia) from the Paw Paw Formation (Late Albian) of Texas". Journal of Vertebrate Paleontology. 16 (2): 232–345. doi:10.1080/02724634.1996.10011311.
^Holtz, T. R.; Rey, L. V. (2007). Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages. Random House. ISBN9780375824197. Genus List for Holtz 2012 Weight Information
^ abPaulina-Carabajal, A.; Lee, Y.N.; Jacobs, L.L. (2016). "Endocranial Morphology of the Primitive Nodosaurid Dinosaur Pawpawsaurus campbelli from the Early Cretaceous of North America". PLOS ONE. 11 (3): e0150845. Bibcode:2016PLoSO..1150845P. doi:10.1371/journal.pone.0150845. PMC4805287. PMID 27007950.
^Vickaryous, M.; Maryanska, T.; Weishampel, D.B. (2004). "Ankylosauria". In Weishampel, David B.; Dodson, Peter; Osmólska, Halzska (eds.). The Dinosauria (2nd ed.). University of California Press.
^"Early armored dinosaur from Texas lacked cousin's club-tail weapon, but had a nose for danger".
External linksedit
Pawpawsaurus web site
Digimorph 3D Pawpawsaurus skull
January 01, 1970
pawpawsaurus, meaning, pawpaw, lizard, nodosaurid, ankylosaur, from, cretaceous, late, albian, tarrant, county, texas, discovered, 1992, only, species, assigned, this, taxon, campbelli, based, complete, skull, lacking, mandibles, from, marine, formation, wachi. Pawpawsaurus meaning Pawpaw Lizard is a nodosaurid ankylosaur from the Cretaceous late Albian of Tarrant County Texas discovered in May 1992 The only species yet assigned to this taxon Pawpawsaurus campbelli is based on a complete skull lacking mandibles from the marine Paw Paw Formation Wachita Group 1 PawpawsaurusTemporal range Early Cretaceous Albian 105 100 Ma PreꞒ Ꞓ O S D C P T J K Pg N Skull in side top back and bottom views Scientific classification Domain Eukaryota Kingdom Animalia Phylum Chordata Clade Dinosauria Clade Ornithischia Clade Thyreophora Clade Ankylosauria Family Nodosauridae Subfamily Nodosaurinae Clade Struthiosaurini Genus PawpawsaurusLee 1996 Species P campbelli Binomial name Pawpawsaurus campbelliLee 1996 Contents 1 Discovery 2 Description 3 Classification 4 Palaeobiology 5 See also 6 References 7 External linksDiscovery editPawpawsaurus was found in the Paw Paw Formation in Tarrant County Texas in May 1992 by Cameron Campbell A complete skull is the only specimen from which the binomial was named Pawpawsaurus campbelli The Paw Paw Formation has produced another nodosaurid Texasetes pleurohalio Coombs 1995 which may prove to be a senior synonym of Pawpawsaurus This is the only nodosaurid known to have possessed the bony eyelids commonly found in ankylosaurids The skull of Pawpawsaurus bears some notable similarities to that of Silvisaurus such as the presence of teeth in the premaxilla and the restriction of the osseous secondary palate to the rostral portion of the palatal region 1 Description edit nbsp Skull cast in front view Pawpawsaurus was a medium sized nodosaur measuring 4 5 metres 15 ft long 2 It is known from a relatively well preserved and complete skull The skull is complete enough for a 2016 study to be able to identify and reconstruct the brain nasal cavities and inner ear of the specimen and CT scan it to find new anatomical features 3 The brain of Pawpawsaurus is very similar to other ankylosaurians but along with more derived taxa it is most different from Kunbarrasaurus The brain is 30 of the skull length very similar to Panoplosaurus higher than Euoplocephalus and lower than Kunbarrasaurus The brain of Pawpawsaurus is 96 millimetres 3 8 in long and 35 millimetres 1 4 in wide The inner ear is also similar to ankylosaurians to the exclusion of Kunbarrasaurus being 27 millimetres 1 1 in tall and 15 5 millimetres 0 61 in wide at the level of the semicircular canals The nasal cavities of Pawpawsaurus resemble that of Panoplosaurus and Euoplocephalus although the thin dividing medians are not preserved as they were likely cartilaginous 3 Classification editVickaryous et al 2004 have stated that Sauropelta edwardsorum Silvisaurus condrayi and Pawpawsaurus campbelli form a basal polytomy nested deep to Cedarpelta 4 Alternatively Pawpawsaurus has been identified as a relative of Struthiosaurus with cladogram below showing the results of the 2018 phylogenetic analysis of Rivera Sylva and colleagues resolving Pawpawsaurus within the clade Struthiosaurini as labelled by Madzia et al with relationships outside Struthiosaurini excluded for simplicity 5 6 Struthiosaurini Hungarosaurus Europelta Pawpawsaurus Stegopelta Struthiosaurus languedocensis Struthiosaurus transylvanicus Struthiosaurus austriacus However the strict consensus tree of a phylogenetic analysis performed by Brown et al 2017 placed Pawpawsaurus in a clade with Borealopelta markmitchelli and Europelta carbonensis The results of the strict consensus are displayed in the phylogeny below with taxa outside Nodosauridae being excluded 7 Nodosauridae Sauroplites scutiger Mymoorapelta maysi Dongyangopelta yangyanensis Gastonia burgei Gargoyleosaurus parkpinorum Polacanthus foxii Peloroplites cedrimontanus Sauropelta edwardsi Nodosaurus textilis Tatankacephalus cooneyorum Silvisaurus condrayi Animantarx ramaljonesi Hungarosaurus tormai Europelta carbonensis Pawpawsaurus campbelli Borealopelta markmitchelli Struthiosaurus austriacus Stegopelta landerensis Panoplosaurus mirus Edmontonia rugosidens Edmontonia longiceps Denversaurus schlessmaniPalaeobiology editPawpawsaurus was primitive in regards to its sensory abilities when compared to later ankylosaurs CT scans of its skull and brain by Paulina Carabajal and Louis Jacobs et al revealed that Pawpawsaurus hearing was on par with that of modern crocodilians indicating that its hearing was relatively poor Its sense of smell meanwhile while not as advanced as that of later ankylosaurs was still more powerful and acute than many of the theropods existent at the time thanks to its large nasal cavities The enlarged nasal cavities of Pawpawsaurus would also likely have been useful for cooling blood that was entering the brain finding food and potential mates or alerting it to danger 8 See also edit nbsp Dinosaurs portal Timeline of ankylosaur researchReferences edit a b Lee Y N 1996 A new nodosaurid ankylosaur Dinosauria Ornithischia from the Paw Paw Formation Late Albian of Texas Journal of Vertebrate Paleontology 16 2 232 345 doi 10 1080 02724634 1996 10011311 Holtz T R Rey L V 2007 Dinosaurs The Most Complete Up to Date Encyclopedia for Dinosaur Lovers of All Ages Random House ISBN 9780375824197 Genus List for Holtz 2012 Weight Information a b Paulina Carabajal A Lee Y N Jacobs L L 2016 Endocranial Morphology of the Primitive Nodosaurid Dinosaur Pawpawsaurus campbelli from the Early Cretaceous of North America PLOS ONE 11 3 e0150845 Bibcode 2016PLoSO 1150845P doi 10 1371 journal pone 0150845 PMC 4805287 PMID 27007950 Vickaryous M Maryanska T Weishampel D B 2004 Ankylosauria In Weishampel David B Dodson Peter Osmolska Halzska eds The Dinosauria 2nd ed University of California Press Madzia D Arbour V M Boyd C A Farke A A Cruzado Caballero P Evans D C 2021 The phylogenetic nomenclature of ornithischian dinosaurs PeerJ 9 e12362 doi 10 7717 peerj 12362 PMC 8667728 PMID 34966571 Rivera Sylva H E Frey E Stinnesbeck W Carbot Chanona G Sanchez Uribe I E Guzman Gutierrez J R 2018 Paleodiversity of Late Cretaceous Ankylosauria from Mexico and their phylogenetic significance Swiss Journal of Palaeontology 137 83 93 doi 10 1007 s13358 018 0153 1 S2CID 134924657 Brown C M Henderson D M Vinther J Fletcher I Sistiaga A Herrera J Summons R E 2017 Supplemental Information An Exceptionally Preserved Three Dimensional Armored Dinosaur Reveals Insights into Coloration and Cretaceous Predator Prey Dynamics Current Biology 27 16 2514 2521 e3 doi 10 1016 j cub 2017 06 071 hdl 1721 1 118950 PMID 28781051 S2CID 5182644 Early armored dinosaur from Texas lacked cousin s club tail weapon but had a nose for danger External links editPawpawsaurus web site Digimorph 3D Pawpawsaurus skull Retrieved from https en wikipedia org w index php title Pawpawsaurus amp oldid 1222647068, wikipedia, wiki, book, books, library,
