[D] Spinops sternbergorum [Su] [sG] [T]
Describer
Farke, Ryan, Barrett, Tanke, Braman, Loewen & Graham 2011
Time
Cretaceous Late Campanian
Classification
Ornithischia Genasauria Cerapoda Marginocephalia Ceratopia Neoceratopia Ceratopidae Centrosaurinae
Diet
Herbivore
Fossilsite
Oldman Formation? - Dinosaur Park Formation?, Dinosaur Provincial Park, Alberta, Canada
Fall under/Typespecies
Info
Abstract
In 1916, a centrosaurine dinosaur bonebed was excavated within the Campanian−aged deposits of what is now Dinosaur Provincial Park, Alberta, Canada. Specimens from this now−lost quarry, including two parietals, a squamosal, a skull missing the frill, and an incomplete dentary, were purchased by The Natural History Museum, London. The material was recently reprepared and identified herein as a previously unknown taxon, Spinops sternbergorum gen. et sp. nov. Based upon the available locality data and paleopalynology, the quarry lies in either the upper part of the Oldman Formation or the lower part of the Dinosaur Park Formation.
The facial region of the partial skull is similar to putative mature specimens of Centrosaurus spp. and Styracosaurus albertensis, with short, rounded postorbital horncores and a large, erect nasal horncore. Parietal ornamentation is consistent on both known parietals and is unique among ceratopsids. Bilateral, procurved parietal hooks occupy the P1 (medial−most) position on the dorsal surface of the parietal and are very similar to those seen in Centrosaurus apertus. Epiparietals in the P2 or possibly P3 position (lateral to P1) manifest as extremely elongate, caudally directed spikes, unlike the condition in C. apertus, S. albertensis, or any other “derived” centrosaurine.
Cladistic analysis suggests that S. sternbergorum is closely related to Centrosaurus and Styracosaurus. Historically, based upon the condition in Styracosaurus and related centrosaurines, it was assumed that the medial−most elongated spikes on centrosaurine parietals correspond to the P3 epiparietal position. The exception illustrated in the new taxon sug− gests that homologies of epiparietals among basal centrosaurines (e.g., Albertaceratops and Diabloceratops) and derived centrosaurines (e.g., Styracosaurus and “pachyrhinosaurs”) should be reconsidered. The medially−placed, caudally−directed “P3” process of basal centrosaurines may, in fact, be homologous with P2.
Etymology
From the Latin spina, spine; and the Greek—ops, face; referring to the ornamentation on the face. | The specific epithet honors Charles H. and Levi Sternberg, collectors of the original specimens.
Holotype
NHMUKR16307, a partial parietal bone, preserving most of the midline bar and a portion of the lateral rami.
Type locality
Exact locality unknown but collected in the vicinity of the Red Deer River, Steveville Badlands, Dinosaur Provincial Park, Alberta, Canada. Attempts to relocate the quarry have been unsuccessful so far.
Type horizon
Unfortunately, only limited stratigraphic data are available. The locality was estimated to be at least 90 m stratigraphically below the quarry that yielded the type specimen of Styracosaurus albertensis (C. H. Sternberg, 9 July 1916 letter to A. Smith Woodward, NHMUK archives; see also Tanke 2010). The S. albertensis locality is approximately 42 m above the contact between the Dinosaur Park Formation and the underlying Oldman Formation.
Because the Oldman Formation is only 40mthick in Dinosaur Provincial Park (Eberth 2005), this would place the type locality for Spinops sternbergorum in the Foremost Formation (which underlies the Oldman Formation). However, the Foremost Formation is not exposed in the immediate region, so Sternberg’s estimation of the stratigraphic position of the quarry is almost certainly incorrect.
Palynological analysis of the matrix from the Spinops bonebed is most consistent with location of the quarry within either the upper few meters of the Oldman Formation or at any level in the Dinosaur Park Formation. Sternberg described the quarry as at floodplain level near Berry Creek; the pattern of exposures in this vicinity suggests that the quarry is no higher than the lower Dinosaur Park Formation and quite possibly in the upper Oldman Formation, which is exposed at floodplain level there.
Definition and diagnosis
A centrosaurine ceratopsid characterized by the following unique combination of characters: a procurving hook as the most medial−most epiparietal (P1) on the caudal margin of the parietal, with a straight, caudally−projecting spike (presumed P2 or possibly P3) with gentle dorsal curvature immediately lateral to the hook; short postorbital horncores that project dorsally; nasal horn core longer than the postorbital horncores.
The prominence of the P1 hooks and their proximity to the caudally−projecting spike distinguish Spinops sternbergorum from Styracosaurus albertensis and other centrosaurines exclusive of Centrosaurus spp., and the caudally−projecting spike distinguishes S. sternbergorum from Centrosaurus spp.
Referred material
NHMUK R16308, a partial parietal bone, preserving portions of the midline bar and lateral rami, with adhered partial dentary and unidentifiable limb elements. NHMUK R16306, an incomplete skull, preserving the dorsal portion of the skull from the rostralmost portion of the midline parietal bar to the caudalmost portion of the premaxillae, lacking all elements ventral to the ventral border of the orbit. NHMUK R16309, a partial right squamosal. Although none of this material was found in articulation, it was all closely associated in the same bone bed and no evidence suggests that any other ceratopsid taxon was present. None of the isolated elements can be assigned confidently to the individual represented by the partial skull.
Farke, Ryan, Barrett, Tanke, Braman, Loewen & Graham 2011
Time
Cretaceous Late Campanian
Classification
Ornithischia Genasauria Cerapoda Marginocephalia Ceratopia Neoceratopia Ceratopidae Centrosaurinae
Diet
Herbivore
Fossilsite
Oldman Formation? - Dinosaur Park Formation?, Dinosaur Provincial Park, Alberta, Canada
Fall under/Typespecies
Info
Abstract
In 1916, a centrosaurine dinosaur bonebed was excavated within the Campanian−aged deposits of what is now Dinosaur Provincial Park, Alberta, Canada. Specimens from this now−lost quarry, including two parietals, a squamosal, a skull missing the frill, and an incomplete dentary, were purchased by The Natural History Museum, London. The material was recently reprepared and identified herein as a previously unknown taxon, Spinops sternbergorum gen. et sp. nov. Based upon the available locality data and paleopalynology, the quarry lies in either the upper part of the Oldman Formation or the lower part of the Dinosaur Park Formation.
The facial region of the partial skull is similar to putative mature specimens of Centrosaurus spp. and Styracosaurus albertensis, with short, rounded postorbital horncores and a large, erect nasal horncore. Parietal ornamentation is consistent on both known parietals and is unique among ceratopsids. Bilateral, procurved parietal hooks occupy the P1 (medial−most) position on the dorsal surface of the parietal and are very similar to those seen in Centrosaurus apertus. Epiparietals in the P2 or possibly P3 position (lateral to P1) manifest as extremely elongate, caudally directed spikes, unlike the condition in C. apertus, S. albertensis, or any other “derived” centrosaurine.
Cladistic analysis suggests that S. sternbergorum is closely related to Centrosaurus and Styracosaurus. Historically, based upon the condition in Styracosaurus and related centrosaurines, it was assumed that the medial−most elongated spikes on centrosaurine parietals correspond to the P3 epiparietal position. The exception illustrated in the new taxon sug− gests that homologies of epiparietals among basal centrosaurines (e.g., Albertaceratops and Diabloceratops) and derived centrosaurines (e.g., Styracosaurus and “pachyrhinosaurs”) should be reconsidered. The medially−placed, caudally−directed “P3” process of basal centrosaurines may, in fact, be homologous with P2.
Etymology
From the Latin spina, spine; and the Greek—ops, face; referring to the ornamentation on the face. | The specific epithet honors Charles H. and Levi Sternberg, collectors of the original specimens.
Holotype
NHMUKR16307, a partial parietal bone, preserving most of the midline bar and a portion of the lateral rami.
Type locality
Exact locality unknown but collected in the vicinity of the Red Deer River, Steveville Badlands, Dinosaur Provincial Park, Alberta, Canada. Attempts to relocate the quarry have been unsuccessful so far.
Type horizon
Unfortunately, only limited stratigraphic data are available. The locality was estimated to be at least 90 m stratigraphically below the quarry that yielded the type specimen of Styracosaurus albertensis (C. H. Sternberg, 9 July 1916 letter to A. Smith Woodward, NHMUK archives; see also Tanke 2010). The S. albertensis locality is approximately 42 m above the contact between the Dinosaur Park Formation and the underlying Oldman Formation.
Because the Oldman Formation is only 40mthick in Dinosaur Provincial Park (Eberth 2005), this would place the type locality for Spinops sternbergorum in the Foremost Formation (which underlies the Oldman Formation). However, the Foremost Formation is not exposed in the immediate region, so Sternberg’s estimation of the stratigraphic position of the quarry is almost certainly incorrect.
Palynological analysis of the matrix from the Spinops bonebed is most consistent with location of the quarry within either the upper few meters of the Oldman Formation or at any level in the Dinosaur Park Formation. Sternberg described the quarry as at floodplain level near Berry Creek; the pattern of exposures in this vicinity suggests that the quarry is no higher than the lower Dinosaur Park Formation and quite possibly in the upper Oldman Formation, which is exposed at floodplain level there.
Definition and diagnosis
A centrosaurine ceratopsid characterized by the following unique combination of characters: a procurving hook as the most medial−most epiparietal (P1) on the caudal margin of the parietal, with a straight, caudally−projecting spike (presumed P2 or possibly P3) with gentle dorsal curvature immediately lateral to the hook; short postorbital horncores that project dorsally; nasal horn core longer than the postorbital horncores.
The prominence of the P1 hooks and their proximity to the caudally−projecting spike distinguish Spinops sternbergorum from Styracosaurus albertensis and other centrosaurines exclusive of Centrosaurus spp., and the caudally−projecting spike distinguishes S. sternbergorum from Centrosaurus spp.
Referred material
NHMUK R16308, a partial parietal bone, preserving portions of the midline bar and lateral rami, with adhered partial dentary and unidentifiable limb elements. NHMUK R16306, an incomplete skull, preserving the dorsal portion of the skull from the rostralmost portion of the midline parietal bar to the caudalmost portion of the premaxillae, lacking all elements ventral to the ventral border of the orbit. NHMUK R16309, a partial right squamosal. Although none of this material was found in articulation, it was all closely associated in the same bone bed and no evidence suggests that any other ceratopsid taxon was present. None of the isolated elements can be assigned confidently to the individual represented by the partial skull.