The etymology of Sphaerotholus is a combination of the Greeksphaira, meaning "ball", and tholos, meaning "dome", and is a reference to the characteristically dome-shaped pachycephalosaurian skull. The survival of Sphaerotholus from the Campanian of New Mexico to the end of the Maastrichtian of Montana demonstrates that this taxon had both a relatively long duration (approximately 7-8 million years) and a widespread distribution. Williamson and Carr, who first described the genus in 2002, diagnose it as follows: "Differs from all other pachycephalosaurids where known in the possession of a parietosquamosal bar that decreases in depth laterally as seen in caudal view and is bordered by a single row of nodes and one lateroventral corner node." Sphaerotholus is considered a highly derived pachycephalosaur.[1]
Species
Sphaerotholus goodwini
The holotype of the type species (NMMNH P-27403, New Mexico Museum of Natural History) consists of an incomplete skull lacking the facial and palatal elements. The species is diagnosed as follows: "Sphaerotholus which in caudal view possesses a parietosquamosal bar that reduces in depth laterally to a lesser extent than in S. buchholtzae and the parietal is reduced to a thin slip between the squamosals." The species name honors paleontologist Mark Goodwin for his work with pachycephalosaurian dinosaurs.[1]
Sphaerotholus buchholtzae
The holotype of S. buchholtzae (TMP 87.113.3) consists of an incomplete skull. The species was diagnosed as having a parietal that is widely exposed between the squamosals and wide enough to bear parietosquamosal nodes, a shallower caudal margin of the parietosquamosal shelf, the lateral corner node is reduced in size and located above the ventral margin of the parietosquamosal bar, and the nodes in the lateral margin of the parietosquamosal shelf reduced on the squamosal and coalescing into a ridge on the postorbital.[1] The specific name honors Emily A. Buchholtz for her extensive work with pachycephalosaurians.
Sullivan (2003) considered S. buchholtzae a junior synonym of Prenocephale edmontonensis (or Sphaerotholus edmontonensis).[2] However, Mallon et al. (2015), in their description of a new S. buchholtzae specimen from the Frenchman Formation of Saskatchewan, Canada, noted that S. edmontonensis was distinct from S. buchholtzae based on comparative morphology and morphometrics.[3]
Sphaerotholus edmontonensis
A Troodon edmontonensis was described by Brown and Schlaikjer in 1943 on the basis of three domes from the Horseshoe Canyon Formation of Alberta.[4] Williamson and Carr considered the species to be invalid,[1] but in 2010 Nicholas Longrich et al. named a Sphaerotholus edmontonensis that could be distinguished from S. goodwini by the paired hornlets on the back of the dome, and from S. buchholtzae by the elongate parietals.[5] It was once considered a species of Stegoceras and was about the same size, reaching 2 m (6.6 ft) in length and 40 kg (88 lb) in body mass.[6]
^ abcdWilliamson Thomas E.; Carr Thomas D. (2002). "A new genus of highly derived pachycephalosaurian from western North America". Journal of Vertebrate Paleontology. 22 (4): 779–801. doi:10.1671/0272-4634(2002)022[0779:angodp]2.0.co;2.
^Robert M. Sullivan (2003). "Revision of the dinosaur Stegoceras Lambe (Ornithischia, Pachycephalosauridae)". Journal of Vertebrate Paleontology. 23 (1): 181–207. doi:10.1671/0272-4634(2003)23[181:rotdsl]2.0.co;2.
^Mallon Jordan C.; Evans David C.; Tokaryk Tim T.; Currie Margaret L. (2015). "First pachycephalosaurid (Dinosauria: Ornithischia) from the Frenchman Formation (upper Maastrichtian) of Saskatchewan, Canada". Cretaceous Research. 56: 426–431. doi:10.1016/j.cretres.2015.06.005.
^Brown B.; Schlaikjer E. M. (1943). "A study of the troödont dinosaurs with a description of a new genus and four new species". Bulletin of the American Museum of Natural History. 82 (5): 115–149.
^Longrich N. R.; Sankey J. T.; et al. (2010). "Texacephale langstoni, a new genus of pachycephalosaurid (Dinosauria: Ornithischia) from the upper Campanian Aguja Formation, southern Texas, USA". Cretaceous Research. 31 (2): 274–284. doi:10.1016/j.cretres.2009.12.002.
^Paul, Gregory S. (2016). The Princeton Field Guide to Dinosaurs. Princeton University Press. p. 269. ISBN978-1-78684-190-2. OCLC 985402380.
Sources
Williamson T. D.; Carr T. E. (2002). "A new genus of highly derived pachycephalosaurian from western North America". Journal of Vertebrate Paleontology. 22 (4): 779–801. doi:10.1671/0272-4634(2002)022[0779:angodp]2.0.co;2.
External links
(includes photograph of the type skull of Sphaerotholus goodwini and a life restoration of same)
August 25, 2023
sphaerotholus, genus, pachycephalosaurid, dinosaur, from, upper, cretaceous, western, united, states, canada, date, three, species, have, been, described, type, species, goodwini, from, member, kirtland, formation, late, campanian, juan, county, mexico, buchho. Sphaerotholus is a genus of pachycephalosaurid dinosaur from the Upper Cretaceous of the western United States and Canada To date three species have been described the type species S goodwini from the Den na zin Member of the Kirtland Formation Late Campanian of San Juan County New Mexico USA S buchholtzae from the Hell Creek Formation Late Maastrichtian of western Carter County Montana USA and the Frenchman Formation of Saskatchewan Canada and S edmontonensis from the Horseshoe Canyon Formation of Alberta Canada SphaerotholusTemporal range Late Cretaceous 73 66 Ma PreꞒ Ꞓ O S D C P T J K Pg NS buchholtzae specimen AMNH 0044Scientific classificationDomain EukaryotaKingdom AnimaliaPhylum ChordataClade DinosauriaClade OrnithischiaSuborder PachycephalosauriaFamily PachycephalosauridaeGenus SphaerotholusWilliamson amp Carr 2002Type species Sphaerotholus goodwiniWilliamson amp Carr 2002Other species S buchholtzae Williamson amp Carr 2002 S edmontonensis Brown amp Schlaikjer 1943 Contents 1 History of discovery 2 Species 2 1 Sphaerotholus goodwini 2 2 Sphaerotholus buchholtzae 2 3 Sphaerotholus edmontonensis 3 See also 4 References 5 Sources 6 External linksHistory of discovery Edit Restoration of a pairThe etymology of Sphaerotholus is a combination of the Greek sphaira meaning ball and tholos meaning dome and is a reference to the characteristically dome shaped pachycephalosaurian skull The survival of Sphaerotholus from the Campanian of New Mexico to the end of the Maastrichtian of Montana demonstrates that this taxon had both a relatively long duration approximately 7 8 million years and a widespread distribution Williamson and Carr who first described the genus in 2002 diagnose it as follows Differs from all other pachycephalosaurids where known in the possession of a parietosquamosal bar that decreases in depth laterally as seen in caudal view and is bordered by a single row of nodes and one lateroventral corner node Sphaerotholus is considered a highly derived pachycephalosaur 1 Species EditSphaerotholus goodwini Edit The holotype of the type species NMMNH P 27403 New Mexico Museum of Natural History consists of an incomplete skull lacking the facial and palatal elements The species is diagnosed as follows Sphaerotholus which in caudal view possesses a parietosquamosal bar that reduces in depth laterally to a lesser extent than in S buchholtzae and the parietal is reduced to a thin slip between the squamosals The species name honors paleontologist Mark Goodwin for his work with pachycephalosaurian dinosaurs 1 Sphaerotholus buchholtzae Edit The holotype of S buchholtzae TMP 87 113 3 consists of an incomplete skull The species was diagnosed as having a parietal that is widely exposed between the squamosals and wide enough to bear parietosquamosal nodes a shallower caudal margin of the parietosquamosal shelf the lateral corner node is reduced in size and located above the ventral margin of the parietosquamosal bar and the nodes in the lateral margin of the parietosquamosal shelf reduced on the squamosal and coalescing into a ridge on the postorbital 1 The specific name honors Emily A Buchholtz for her extensive work with pachycephalosaurians Sullivan 2003 considered S buchholtzae a junior synonym of Prenocephale edmontonensis or Sphaerotholus edmontonensis 2 However Mallon et al 2015 in their description of a new S buchholtzae specimen from the Frenchman Formation of Saskatchewan Canada noted that S edmontonensis was distinct from S buchholtzae based on comparative morphology and morphometrics 3 Sphaerotholus edmontonensis Edit A Troodon edmontonensis was described by Brown and Schlaikjer in 1943 on the basis of three domes from the Horseshoe Canyon Formation of Alberta 4 Williamson and Carr considered the species to be invalid 1 but in 2010 Nicholas Longrich et al named a Sphaerotholus edmontonensis that could be distinguished from S goodwini by the paired hornlets on the back of the dome and from S buchholtzae by the elongate parietals 5 It was once considered a species of Stegoceras and was about the same size reaching 2 m 6 6 ft in length and 40 kg 88 lb in body mass 6 See also Edit Dinosaurs portalTimeline of pachycephalosaur researchReferences Edit a b c d Williamson Thomas E Carr Thomas D 2002 A new genus of highly derived pachycephalosaurian from western North America Journal of Vertebrate Paleontology 22 4 779 801 doi 10 1671 0272 4634 2002 022 0779 angodp 2 0 co 2 Robert M Sullivan 2003 Revision of the dinosaur Stegoceras Lambe Ornithischia Pachycephalosauridae Journal of Vertebrate Paleontology 23 1 181 207 doi 10 1671 0272 4634 2003 23 181 rotdsl 2 0 co 2 Mallon Jordan C Evans David C Tokaryk Tim T Currie Margaret L 2015 First pachycephalosaurid Dinosauria Ornithischia from the Frenchman Formation upper Maastrichtian of Saskatchewan Canada Cretaceous Research 56 426 431 doi 10 1016 j cretres 2015 06 005 Brown B Schlaikjer E M 1943 A study of the troodont dinosaurs with a description of a new genus and four new species Bulletin of the American Museum of Natural History 82 5 115 149 Longrich N R Sankey J T et al 2010 Texacephale langstoni a new genus of pachycephalosaurid Dinosauria Ornithischia from the upper Campanian Aguja Formation southern Texas USA Cretaceous Research 31 2 274 284 doi 10 1016 j cretres 2009 12 002 Paul Gregory S 2016 The Princeton Field Guide to Dinosaurs Princeton University Press p 269 ISBN 978 1 78684 190 2 OCLC 985402380 Sources EditWilliamson T D Carr T E 2002 A new genus of highly derived pachycephalosaurian from western North America Journal of Vertebrate Paleontology 22 4 779 801 doi 10 1671 0272 4634 2002 022 0779 angodp 2 0 co 2 External links Editdinosaur net cn includes photograph of the type skull of Sphaerotholus goodwini and a life restoration of same Retrieved from https en wikipedia org w index php title Sphaerotholus amp oldid 1156718336, wikipedia, wiki, book, books, library,
