scholarly journals Xenoposeidon is the earliest known rebbachisaurid sauropod dinosaur

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5212 ◽  
Author(s):  
Michael P. Taylor
Keyword(s):  
Early Cretaceous ◽  
3D Models ◽  
Lateral Face ◽  
Neural Arch ◽  
Dorsal Vertebra ◽  
Southern England

Xenoposeidon proneneukos is a sauropod dinosaur from the Early Cretaceous Hastings Group of England. It is represented by a single partial dorsal vertebra, NHMUK PV R2095, which consists of the centrum and the base of a tall neural arch. Despite its fragmentary nature, it is recognisably distinct from all other sauropods, and is here diagnosed with five unique characters. One character previously considered unique is here recognised as shared with the rebbachisaurid diplodocoid Rebbachisaurus garasbae from the mid-Cretaceous of Morocco: an ‘M’-shaped arrangement of laminae on the lateral face of the neural arch. Following the more completely preserved R. garasbae, these laminae are now interpreted as ACPL and lateral CPRL, which intersect anteriorly; and PCDL and CPOL, which intersect posteriorly. Similar arrangements are also seen in some other rebbachisaurid specimens (though not all, possibly due to serial variation), but never in non-rebbachisaurid sauropods. Xenoposeidon is therefore referred to Rebbachisauridae. Due to its inferred elevated parapophysis, the holotype vertebra is considered a mid-posterior dorsal despite its elongate centrum. Since Xenoposeidon is from the Berriasian–Valanginian (earliest Cretaceous) Ashdown Formation of the Wealden Supergroup of southern England, it is the earliest known rebbachisaurid by some 10 million years. Electronic 3D models were invaluable in determining Xenoposeidon’s true affinities: descriptions of complex bones such as sauropod vertebrae should always provide them where possible.

scholarly journals Xenoposeidon is the earliest known rebbachisaurid sauropod dinosaur

2017 ◽  
Author(s):  
Michael P Taylor
Keyword(s):  
3D Models ◽  
Lateral Face ◽  
Neural Arch ◽  
Dorsal Vertebra ◽  
Southern England

Xenoposeidon proneneukos is a sauropod dinosaur represented by a single partial dorsal vertebra, NHMUK R2095, which consists of the centrum and the base of a tall neural arch. Despite its fragmentary nature, it is recognisably distinct from all other sauropods, and is here diagnosed with five unique characters. One character previously considered unique is here recognised as shared with Rebbachisaurus garasbae: an “M”-shaped arrangement of laminae on the lateral face of the neural arch. Following the more complete Rebbachisaurus garasbae, these laminae are now interpreted as ACPL and lateral CPRL, which intersect anteriorly; and PCDL and CPOL, which intersect posteriorly. Similar arrangements are also seen in some other rebbachisaurid specimens (though not all, possibly due to serial variation), but never in non-rebbachisaurid sauropods. Xenoposeidon is therefore referred to Rebbachisauridae. Due to its elevated parapophysis, the holotype vertebra is considered a posterior dorsal despite its elongate centrum. Since Xenoposeidon is from the from the Berriasian–Valanginian (earliest Cretaceous) Ashdown Beds Formation of the Wealden Supergroup of southern England, it is the earliest known rebbachisaurid by some 10 million years. Electronic 3D models were invaluable in determining Xenoposeidon's true affinities: descriptions of complex bones such as sauropod vertebrae should always provide them where possible.

scholarly journals Xenoposeidon is the earliest known rebbachisaurid sauropod dinosaur

2017 ◽  
Author(s):  
Michael P Taylor
Keyword(s):  
3D Models ◽  
Lateral Face ◽  
Neural Arch ◽  
Dorsal Vertebra ◽  
Southern England

Xenoposeidon proneneukos is a sauropod dinosaur represented by a single partial dorsal vertebra, NHMUK R2095, which consists of the centrum and the base of a tall neural arch. Despite its fragmentary nature, it is recognisably distinct from all other sauropods, and is here diagnosed with five unique characters. One character previously considered unique is here recognised as shared with Rebbachisaurus garasbae: an “M”-shaped arrangement of laminae on the lateral face of the neural arch. Following the more complete Rebbachisaurus garasbae, these laminae are now interpreted as ACPL and lateral CPRL, which intersect anteriorly; and PCDL and CPOL, which intersect posteriorly. Similar arrangements are also seen in some other rebbachisaurid specimens (though not all, possibly due to serial variation), but never in non-rebbachisaurid sauropods. Xenoposeidon is therefore referred to Rebbachisauridae. Due to its elevated parapophysis, the holotype vertebra is considered a posterior dorsal despite its elongate centrum. Since Xenoposeidon is from the from the Berriasian–Valanginian (earliest Cretaceous) Ashdown Beds Formation of the Wealden Supergroup of southern England, it is the earliest known rebbachisaurid by some 10 million years. Electronic 3D models were invaluable in determining Xenoposeidon's true affinities: descriptions of complex bones such as sauropod vertebrae should always provide them where possible.

scholarly journals A new aquatic crustacean (Isopoda: Cymothoida) from the early Cretaceous of southern England and comparison with the Chinese and Iberian biotas

2014 ◽  
Vol 125 (4) ◽  
pp. 446-451 ◽  
Author(s):  
Edmund A. Jarzembowski ◽  
B. Wang ◽  
Y. Fang ◽  
H. Zhang
Keyword(s):  
Early Cretaceous ◽  
Southern England

scholarly journals Insight on the anatomy, systematic relationships, and age of the Early Cretaceous ankylopollexian dinosaur Dakotadon lakotaensis

2015 ◽  
Author(s):  
Clint A Boyd ◽  
Darrin C Pagnac
Keyword(s):  
Early Cretaceous ◽  
Original Description ◽  
Field Work ◽  
Optimality Criteria ◽  
Dorsal Vertebra ◽  
The Past ◽  
Caudal Vertebrae ◽  
Systematic Relationships ◽  
Preparation Work ◽  
Extensive Deformation

Knowledge regarding the early evolution within the dinosaurian clade Ankylopollexia drastically increased over the past two decades, in part because of an increase in described taxa from the Early Cretaceous of North America. These advances motivated the recent completion of extensive preparation and conservation work on the holotype and only known specimen of Dakotadon lakotaensis, a basal ankylopollexian from the Lakota Formation of South Dakota. That specimen (SDSM 8656) preserves a partial skull, lower jaws, a single dorsal vertebra, and two caudal vertebrae. That new preparation work exposed several bones not included in the original description and revealed that other bones were previously misidentified. The presence of extensive deformation in areas of the skull is also noted that influenced inaccuracies in prior descriptions and reconstructions of this taxon. In addition to providing an extensive re-description of D. lakotaensis, this study reviews previously proposed diagnoses for this taxon, identifies two autapomorphies, and provides an extensive differential diagnosis. Dakotadon lakotaensis is distinct from the only other ankylopollexian taxon known from the Lakota Formation, Osmakasaurus depressus, in the presence of two prominent, anteroposteriorly oriented ridges on the ventral surfaces of the caudal vertebrae, the only overlapping material preserved between these taxa. The systematic relationships of D. lakotaensis are evaluated using both the parsimony and posterior probability optimality criteria, with both sets of analyses recovering D. lakotaensis as a non-hadrosauriform ankylopollexian that is more closely related to taxa from the Early Cretaceous (e.g., Iguanacolossus, Hippodraco, and Theiophytalia) than to more basally situated taxa from the Jurassic (e.g., Camptosaurus, Uteodon). This taxonomic work is supplemented by field work that relocated the type locality, confirming its provenance from unit L2 (lower Fuson Member equivalent) of the Lakota Formation. Those data, combined with recently revised ages for the members of the Lakota Formation based on charophyte and ostracod biostratigraphy, constrain the age of this taxon to the late Valanginian to early Barremian.

Fossil caddisflies (Insecta: Trichoptera) from the Early Cretaceous of southern England II

2001 ◽  
Vol 22 (6) ◽  
pp. 685-694 ◽  
Author(s):  
I.D. Sukatsheva ◽  
E.A. Jarzembowski
Keyword(s):  
Early Cretaceous ◽  
Southern England

scholarly journals Insight on the anatomy, systematic relationships, and age of the Early Cretaceous ankylopollexian dinosaur Dakotadon lakotaensis

2015 ◽  
Author(s):  
Clint A Boyd ◽  
Darrin C Pagnac
Keyword(s):  
North America ◽  
Early Cretaceous ◽  
Original Description ◽  
Field Work ◽  
Optimality Criteria ◽  
Dorsal Vertebra ◽  
Caudal Vertebrae ◽  
Systematic Relationships ◽  
Preparation Work ◽  
Extensive Deformation

Knowledge regarding the early evolution within the dinosaurian clade Ankylopollexia drastically increased over the past two decades, in part because of an increase in described taxa from the Early Cretaceous of North America. These advances motivated the recent completion of extensive preparation and conservation work on the holotype and only known specimen of Dakotadon lakotaensis, a basal ankylopollexian from the Lakota Formation of South Dakota. That specimen (SDSM 8656) preserves a partial skull, lower jaws, a single dorsal vertebra, and two caudal vertebrae. That new preparation work exposed several bones not included in the original description and revealed that other bones were previously misidentified. The presence of extensive deformation in areas of the skull is also noted that influenced inaccuracies in prior descriptions and reconstructions of this taxon. In addition to providing an extensive re-description of D. lakotaensis, this study reviews previously proposed diagnoses for this taxon, identifies three autapomorphies, and provides an extensive differential diagnosis. Dakotadon lakotaensis is distinct from the only other ankylopollexian taxon known from the Lakota Formation, Osmakasaurus depressus, in the presence of two prominent, anteroposteriorly oriented ridges on the ventral surfaces of the caudal vertebrae, the only overlapping material preserved between these taxa. The systematic relationships of Dakotadon lakotaensis are evaluated using both the parsimony and posterior probability optimality criteria, with both sets of analyses recovering D. lakotaensis as a non-hadrosauriform ankylopollexian that is more closely related to taxa from the early Cretaceous (e.g., Iguanacolossus, Hippodraco, and Theiophytalia) than to more basally situated taxa from the Jurassic (e.g., Camptosaurus, Uteodon). This taxonomic work is supplemented by field work that relocated the type locality, confirming its provenance from unit L2 (lower Fuson Member equivalent) of the Lakota Formation. Those data, combined with recently revised ages for the members of the Lakota Formation based on charophyte and ostracod biostratigraphy, constrain the age of this taxon to the late Valanginian to early Hauterivian. The only other equivalent-aged ankylopollexian taxon from North America, the poorly known Planicoxa venenica from the Poison Strip Sandstone of Utah, preserves caudal vertebrae that bear the same ventral ridges seen in D. lakotaensis, raising the possibility of a close affinity between these taxa.

scholarly journals Pterosaurs of the Wessex Formation (Early Cretaceous, Barremian) of the Isle of Wight, southern England: a review with new data

2010 ◽  
Vol 36 (2) ◽  
pp. 225-242 ◽  
Author(s):  
S. C. Sweetman ◽  
D. M. Martill
Keyword(s):  
Early Cretaceous ◽  
Isle Of Wight ◽  
Southern England

scholarly journals Immature Insect Assemblages from the Early Cretaceous (Purbeck/Wealden) of Southern England

Insects ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 942
Author(s):  
Robert A. Coram ◽  
Edmund A. Jarzembowski
Keyword(s):  
Early Cretaceous ◽  
Lower Cretaceous ◽  
Aquatic Insects ◽  
Trace Fossils ◽  
Southern England ◽  
Habitat Stability ◽  
Complicating Factors ◽  
Terrestrial Insects

The record of immature insects from the non-marine Purbeck and Wealden groups (Lower Cretaceous) of southern England is reviewed and expanded. Fossils of adult terrestrial insects are locally common, but terrestrial immature remains are restricted to transported hemipterans, most of which are sessile nymphs or puparia resembling those of extant whiteflies (Aleyrodidae). Remains of immature aquatic insects are more diverse and comprise the extant orders Plecoptera, Ephemeroptera, Odonata, Trichoptera, Hemiptera and Diptera. The Trichoptera are represented by larval cases constructed from a variety of materials corresponding to several ichnogenera. The Wealden immature insects were preserved in predominantly freshwater fluvial settings, whereas the Purbeck ones occur in lagoonal palaeoenvironments, ranging in salinity from brackish to hypersaline. The composition of aquatic immature insect faunas in the latter offers potential for palaeosalinity analysis, although there are complicating factors relating to habitat stability. Uncommon trace fossils such as beetle borings in wood provide evidence of immature insects not represented by body fossils.

A possible azhdarchid pterosaur (Pterosauria, Azhdarchidae) in the Durlston Formation (Early Cretaceous, Berriasian) of southern England

2013 ◽  
Vol 43 ◽  
pp. 26-39 ◽  
Author(s):  
David M. Martill ◽  
Michael O'Sullivan ◽  
Charlie Newman
Keyword(s):  
Early Cretaceous ◽  
Southern England
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