[D] Tatankacephalus cooneyrum [Su] [sG] [T]
Describer
Parsons & Parsons 2009
Time
Cretaceous Early Aptian Albian
Classification
Ornithischia Thyreophora Eurypoda Ankylosauria Ankylosauridae
Diet
Herbivore
Fossilsite
Cloverly Formation, Montana, US
Info
Abstract
A cranium and other associated skeletal elements representing a new ankylosaurid dinosaur, Tatankacephalus cooneyrum gen. et. sp. nov. possess several diagnostic features that indicate that this new taxon differs from the only other know ankylosaur from the Cloverly Formation, Sauropelta edwardsorum.
These features include a frontoparietal dome, an enlarged nuchal ridge that obscures the occpital region, a circular orbit, ventral curvature in the posterolatelrally directed paroccipital processes, a posteroventrally directed foramen magnum, and a number of features on the braincase.
The phylogenetic analysis positions Tatankacephalus with Ankylosauridae based on its sharing of several characters with other members of this clade, including an enlarged nuchal segment that obscures the occiput in dorsal view, a ventrally curving lateral profile of the cranium anterior to the orbit, pyramidal postorbital boss, laterally projecting pyramidal quadratojugal boss, the presence of a postocular shelf, the presence of paranasal sinuses, and the lack of a cingulum on a maxillary (or dentary) tooth.
It is considered a basal member of Ankylosauridae because it retains premaxillary teeth and a visible lateral temporal fenestra, in contrast to the absence of premaxillary teeth and an obscured lateral temporal fenestra in younger members of this clade.
Holotype
MOR 1073. Partial cranium consiting of a fragmentary portion of the nasal region with a fragmentary internasal septum, premaxillary fragments with three alveoli, maxiallry-nasal fragment, an isolated (maxillary or dentary) tooth, and a large posterior cranial fragment, including parietal, squamosal, occiput, dorsal portion of left quadrate, braincase, right postorbital, right orbit, parital pterygoids, basisphenoid, partial basioccipital, and parasphenoidal rostrum. Rib fragments and two ventrally concave, hollow, fragmentary osteoderms may belong to the same individual. [Parsons & Parsons, 2001, reported a skull MOR 1073, and additional postcranial material from the basal portion of Unit Vii of the Cloverly Formation, in the Middle Dome region of central Montana the remains are referred by the authors to Sauropelta edwardsi [Sauropelta edwardsorum] (holotype: AMNH 3032) which does not include a skull.]
Etymology
Tatanka, Oglala language, refers to Bison bison; cephalus, Latin for head. In dorsal view, the cranium of Tatankacephalus is similar in proportions to the cranium of Bison bison. The specific name honors the family of John Patrick Cooney.
Type locality
Middle Dome region, Harlowton, Wheatland County, Montana, USA
Type horizon
Cloverly Formation, Lower Cretaceous, late Aptian to early Albian
Diagnosis
Medium-sized ankylosaurid with following autapomorphies: unsegmented enlarged nuchal ridge; concave lateral process projecting, from paroccipital process; and keeled osteodom om jugal process of quadratojugal dorsal to quadratojugal boss.
Tatankacephalus differs from Gastonia (Kirkland, 1998) in possession of premaxillary teeth; in regionof frontal and parietal, lateral profile of frontoparietal dome creates convex appearance of cranial roof; and nuchal shelf with dorsally obscured occiput.
Tatankacephalus differs from Gargoyleosaurus (Carpenter et al. 1998; Kilbourne and Carpenter 2005) in lack of alignment of premaxillary and maxillary tooth rows; in region of frontal and parrietal, lateral profile of frontparietal dome creates convex appearance of cranial roof; and circular orbit.
Tatankacephalus differs from Gobisaurus (Vickayous et al 2001, 2004) in region of frontal and parietal, lateral profile of frontparietal dome creates convex appearance of cranial roof, visible lateral temporal fenestra; and width between squamosals less than width between supraorbitals.
Tatankacephalus differs from Minmi (Molnar, 2001; Vickaryous et al 2004) in region of frontal and parietal, lateral profile of frontparietal dome creates convex appearance of cranial roof; visible lateral temporal fenestra; and maxumum premaxillary rostrum width greater tha distance between posteriormost maxillary teeth.
Tatankacephalus differs from Shamosaurus (Tumanova 1987; Vickaryous et al 2004) in presence of premaxillary teeth; in region of frontal and parietal, lateral profile of frontoparietal dome creates convex appearance of cranial roof; and visible lateral temporal fenestra.
Tatankacephalus differs from Tsagantegia (Tumanova 1993; Vickaryous et al 2004) in region of frontal and parietal, lateral profile of frontoparietal dome creates convex appearance of cranial roof; pyramidal quadratojugal boss; premaxillary teeth; basipterygoid process fused with quadrate ramus of pterygoid; and basisphenoid length less than basioccipital.
Tatankacephalus differs from Cedarpelta (Carpenter et al 2001) with lateral temporal fenestra visible in lateral view; in region of frontal and parietal lateral profile of frontoparietal dome creates convex appearance of cranial roof; occipital condyle oreintation directed posteroventrally; and quadrate-paroccipital process fused.
Tatankacephalus differs from Sauropelta (Vickaryous et al 2004) in posteroventrally diected opening of foramen magnum; in region of frontal ans parietal, lateral profile of frontoparietal dome creates convex appearance of cranial roof; nuchal shelf dorsally obscuring occiput; curved lateral profile anterior to orbit; and circular orbit.
Parsons & Parsons 2009
Time
Cretaceous Early Aptian Albian
Classification
Ornithischia Thyreophora Eurypoda Ankylosauria Ankylosauridae
Diet
Herbivore
Fossilsite
Cloverly Formation, Montana, US
Info
Abstract
A cranium and other associated skeletal elements representing a new ankylosaurid dinosaur, Tatankacephalus cooneyrum gen. et. sp. nov. possess several diagnostic features that indicate that this new taxon differs from the only other know ankylosaur from the Cloverly Formation, Sauropelta edwardsorum.
These features include a frontoparietal dome, an enlarged nuchal ridge that obscures the occpital region, a circular orbit, ventral curvature in the posterolatelrally directed paroccipital processes, a posteroventrally directed foramen magnum, and a number of features on the braincase.
The phylogenetic analysis positions Tatankacephalus with Ankylosauridae based on its sharing of several characters with other members of this clade, including an enlarged nuchal segment that obscures the occiput in dorsal view, a ventrally curving lateral profile of the cranium anterior to the orbit, pyramidal postorbital boss, laterally projecting pyramidal quadratojugal boss, the presence of a postocular shelf, the presence of paranasal sinuses, and the lack of a cingulum on a maxillary (or dentary) tooth.
It is considered a basal member of Ankylosauridae because it retains premaxillary teeth and a visible lateral temporal fenestra, in contrast to the absence of premaxillary teeth and an obscured lateral temporal fenestra in younger members of this clade.
Holotype
MOR 1073. Partial cranium consiting of a fragmentary portion of the nasal region with a fragmentary internasal septum, premaxillary fragments with three alveoli, maxiallry-nasal fragment, an isolated (maxillary or dentary) tooth, and a large posterior cranial fragment, including parietal, squamosal, occiput, dorsal portion of left quadrate, braincase, right postorbital, right orbit, parital pterygoids, basisphenoid, partial basioccipital, and parasphenoidal rostrum. Rib fragments and two ventrally concave, hollow, fragmentary osteoderms may belong to the same individual. [Parsons & Parsons, 2001, reported a skull MOR 1073, and additional postcranial material from the basal portion of Unit Vii of the Cloverly Formation, in the Middle Dome region of central Montana the remains are referred by the authors to Sauropelta edwardsi [Sauropelta edwardsorum] (holotype: AMNH 3032) which does not include a skull.]
Etymology
Tatanka, Oglala language, refers to Bison bison; cephalus, Latin for head. In dorsal view, the cranium of Tatankacephalus is similar in proportions to the cranium of Bison bison. The specific name honors the family of John Patrick Cooney.
Type locality
Middle Dome region, Harlowton, Wheatland County, Montana, USA
Type horizon
Cloverly Formation, Lower Cretaceous, late Aptian to early Albian
Diagnosis
Medium-sized ankylosaurid with following autapomorphies: unsegmented enlarged nuchal ridge; concave lateral process projecting, from paroccipital process; and keeled osteodom om jugal process of quadratojugal dorsal to quadratojugal boss.
Tatankacephalus differs from Gastonia (Kirkland, 1998) in possession of premaxillary teeth; in regionof frontal and parietal, lateral profile of frontoparietal dome creates convex appearance of cranial roof; and nuchal shelf with dorsally obscured occiput.
Tatankacephalus differs from Gargoyleosaurus (Carpenter et al. 1998; Kilbourne and Carpenter 2005) in lack of alignment of premaxillary and maxillary tooth rows; in region of frontal and parrietal, lateral profile of frontparietal dome creates convex appearance of cranial roof; and circular orbit.
Tatankacephalus differs from Gobisaurus (Vickayous et al 2001, 2004) in region of frontal and parietal, lateral profile of frontparietal dome creates convex appearance of cranial roof, visible lateral temporal fenestra; and width between squamosals less than width between supraorbitals.
Tatankacephalus differs from Minmi (Molnar, 2001; Vickaryous et al 2004) in region of frontal and parietal, lateral profile of frontparietal dome creates convex appearance of cranial roof; visible lateral temporal fenestra; and maxumum premaxillary rostrum width greater tha distance between posteriormost maxillary teeth.
Tatankacephalus differs from Shamosaurus (Tumanova 1987; Vickaryous et al 2004) in presence of premaxillary teeth; in region of frontal and parietal, lateral profile of frontoparietal dome creates convex appearance of cranial roof; and visible lateral temporal fenestra.
Tatankacephalus differs from Tsagantegia (Tumanova 1993; Vickaryous et al 2004) in region of frontal and parietal, lateral profile of frontoparietal dome creates convex appearance of cranial roof; pyramidal quadratojugal boss; premaxillary teeth; basipterygoid process fused with quadrate ramus of pterygoid; and basisphenoid length less than basioccipital.
Tatankacephalus differs from Cedarpelta (Carpenter et al 2001) with lateral temporal fenestra visible in lateral view; in region of frontal and parietal lateral profile of frontoparietal dome creates convex appearance of cranial roof; occipital condyle oreintation directed posteroventrally; and quadrate-paroccipital process fused.
Tatankacephalus differs from Sauropelta (Vickaryous et al 2004) in posteroventrally diected opening of foramen magnum; in region of frontal ans parietal, lateral profile of frontoparietal dome creates convex appearance of cranial roof; nuchal shelf dorsally obscuring occiput; curved lateral profile anterior to orbit; and circular orbit.