scholarly journals New specimen and revision of the late Jurassic teleosaurid 'Steneosaurus’ megarhinus

2015 ◽  
Author(s):  
Davide Foffa ◽  
Mark T Young ◽  
Stephen L Brusatte ◽  
Lorna Steel
Keyword(s):  
Fossil Record ◽  
Late Jurassic ◽  
Anterior Margin ◽  
Unique Combination ◽  
Coastal Marine ◽  
Successful Group ◽  
Clay Formation ◽  
Tooth Count

Teleosaurids were a successful group of semi-aquatic crocodylomorphs that were an abundant part of coastal marine/lagoonal faunas during the Jurassic. Their fossil record suggests that the group declined in diversity and abundance during the Late Jurassic. 'Steneosaurus’ megarhinus (Hulke, 1871) from the Kimmeridge Clay Formation is a little known gracile longirostrine species of teleosaurid from the Late Jurassic (late Kimmeridgian). The holotype, an incomplete snout NHMUK PV OR43086, was firstly described by Hulke in 1871. Since then only one other specimen, an almost complete skull from the slightly older Aulacostephanus eudoxus Sub-Boreal ammonite Zone of “La Crouzette”, Francoulès (Quercy, France), has been referred to this species. Here, we describe, DORCM G.5067i-v, the anterior rostrum of a teleosaurid from the same horizon and locality as the holotype. We demonstrate that DORCM G.5067i-v is referable to Steneosaurus’ megarhinus based on a unique combination of characters, which include: strongly ventrally deflected anterior margin of the premaxilla; five premaxillary alveoli, the caudal-most being considerably reduced in size; anterodorsally oriented external nares; conical teeth bearing carinae which are only visible on the apical third of the crown. Importantly, the tooth count, shape of external nares and strong premaxillary deflection distinguish Steneosaurus’ megarhinus from all other Middle and Late Jurassic longirostrine teleosaurids. Some of these characteristics resemble those seen in pholidosaurids, suggesting some convergence between these clades.

scholarly journals New specimen and revision of the late Jurassic teleosaurid 'Steneosaurus’ megarhinus

2015 ◽  
Author(s):  
Davide Foffa ◽  
Mark T Young ◽  
Stephen L Brusatte ◽  
Lorna Steel
Keyword(s):  
Fossil Record ◽  
Late Jurassic ◽  
Anterior Margin ◽  
Unique Combination ◽  
Coastal Marine ◽  
Successful Group ◽  
Clay Formation ◽  
Tooth Count

Teleosaurids were a successful group of semi-aquatic crocodylomorphs that were an abundant part of coastal marine/lagoonal faunas during the Jurassic. Their fossil record suggests that the group declined in diversity and abundance during the Late Jurassic. 'Steneosaurus’ megarhinus (Hulke, 1871) from the Kimmeridge Clay Formation is a little known gracile longirostrine species of teleosaurid from the Late Jurassic (late Kimmeridgian). The holotype, an incomplete snout NHMUK PV OR43086, was firstly described by Hulke in 1871. Since then only one other specimen, an almost complete skull from the slightly older Aulacostephanus eudoxus Sub-Boreal ammonite Zone of “La Crouzette”, Francoulès (Quercy, France), has been referred to this species. Here, we describe, DORCM G.5067i-v, the anterior rostrum of a teleosaurid from the same horizon and locality as the holotype. We demonstrate that DORCM G.5067i-v is referable to Steneosaurus’ megarhinus based on a unique combination of characters, which include: strongly ventrally deflected anterior margin of the premaxilla; five premaxillary alveoli, the caudal-most being considerably reduced in size; anterodorsally oriented external nares; conical teeth bearing carinae which are only visible on the apical third of the crown. Importantly, the tooth count, shape of external nares and strong premaxillary deflection distinguish Steneosaurus’ megarhinus from all other Middle and Late Jurassic longirostrine teleosaurids. Some of these characteristics resemble those seen in pholidosaurids, suggesting some convergence between these clades.

scholarly journals Revision of the Late Jurassic deep-water teleosauroid crocodylomorph Teleosaurus megarhinus Hulke, 1871 and evidence of pelagic adaptations in Teleosauroidea

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6646 ◽  
Author(s):  
Davide Foffa ◽  
Michela M. Johnson ◽  
Mark T. Young ◽  
Lorna Steel ◽  
Stephen L. Brusatte
Keyword(s):  
Phylogenetic Analysis ◽  
Deep Water ◽  
Fossil Record ◽  
Late Jurassic ◽  
Monotypic Genus ◽  
Tooth Crown ◽  
Coastal Marine ◽  
Successful Group ◽  
Valid Taxon ◽  
Clay Formation

Teleosauroids were a successful group of semi-aquatic crocodylomorphs that were an integral part of coastal marine/lagoonal faunas during the Jurassic. Their fossil record suggests that the group declined in diversity and abundance in deep water deposits during the Late Jurassic. One of the few known teleosauroid species from the deeper water horizons of the well-known Kimmeridge Clay Formation is ‘Teleosaurus’ megarhinus Hulke, 1871, a poorly studied, gracile longirostrine form. The holotype is an incomplete snout from the Aulacostephanus autissiodorensis Sub-Boreal ammonite Zone of Kimmeridge, England. The only other referred specimen is an almost complete skull from the slightly older A. eudoxus Sub-Boreal ammonite Zone of Quercy, France. Recently, the validity of this species has been called into question. Here we re-describe the holotype as well as the referred French specimen and another incomplete teleosauroid, DORCM G.05067i-v (an anterior rostrum with three osteoderms and an isolated tooth crown), from the same horizon and locality as the holotype. We demonstrate that all specimens are referable to ‘Teleosaurus’ megarhinus and that the species is indeed a valid taxon, which we assign to a new monotypic genus, Bathysuchus. In our phylogenetic analysis, the latest iteration of the ongoing Crocodylomorph SuperMatrix Project, Bathysuchus megarhinus is found as sister taxon to Aeolodon priscus within a subclade containing Mycterosuchus nasutus and Teleosaurus cadomensis. Notably Bathysuchus has an extreme reduction in dermatocranial ornamentation and osteoderm size, thickness and ornamentation. These features are mirrored in Aeolodon priscus, a species with a well-preserved post-cranial skeleton and a similar shallow and inconspicuous dermal ornamentation. Based on these morphological features, and sedimentological evidence, we hypothesise that the Bathysuchus + Aeolodon clade is the first known teleosauroid lineage that evolved a more pelagic lifestyle.

scholarly journals Evidence of macrophagous teleosaurid crocodylomorphs in the Corallian Group (Oxfordian, Late Jurassic) of the UK

PeerJ ◽  
2015 ◽  
Vol 3 ◽  
pp. e1497 ◽  
Author(s):  
Davide Foffa ◽  
Mark T. Young ◽  
Stephen L. Brusatte
Keyword(s):  
Fossil Record ◽  
Late Jurassic ◽  
Time Span ◽  
Specific Level ◽  
Lower Jaw ◽  
Abundance And Diversity ◽  
The Uk ◽  
Clay Formation ◽  
Tooth Count

Teleosaurids were a group of semi-aquatic crocodylomorphs with a fossil record that spanned the Jurassic Period. In the UK, abundant specimens are known from the Oxford Clay Formation (OCF, Callovian to lower Oxfordian), but are very rare in the Kimmeridge Clay Formation (KCF, Kimmeridgian to lower Tithonian), despite their abundance in some contemporaneous deposits in continental Europe. Unfortunately, due to the paucity of material from the intermediate ‘Corallian Gap’ (middle to upper Oxfordian), we lack an understanding of how and why teleosaurid taxic abundance and diversity declined from the OCF to the KCF. The recognition of an incomplete teleosaurid lower jaw from the Corallian of Weymouth (Dorset, UK) begins to rectify this. The vertically oriented dentition, blunt tooth apices, intense enamel ornamentation that shifts to an anastomosed pattern apically, and deep reception pits on the dentary unambiguously demonstrates the affinity of this specimen with an unnamed sub-clade of macrophagous/durophagous teleosaurids (‘Steneosaurus’obtusidens+Machimosaurus). The high symphyseal tooth count allows us to exclude the specimen fromM. hugiiandM. mosae, but in absence of more diagnostic material we cannot unambiguously assign DORCM G.3939 to a more specific level. Nevertheless, this specimen represents the first mandibular material referable to Teleosauridae from the poorly sampled middle-upper Oxfordian time-span in the UK.

scholarly journals A new sphenodontian (Lepidosauria: Rhynchocephalia) from the Late Triassic of Argentina and the early origin of the herbivore opisthodontians

2013 ◽  
Vol 280 (1772) ◽  
pp. 20132057 ◽  
Author(s):  
Ricardo N. Martínez ◽  
Cecilia Apaldetti ◽  
Carina E. Colombi ◽  
Angel Praderio ◽  
Eliana Fernandez ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
South America ◽  
Late Cretaceous ◽  
Fossil Record ◽  
Late Jurassic ◽  
Upper Triassic ◽  
Late Triassic ◽  
Northwestern Argentina ◽  
Successful Group ◽  
Early Origin

Sphenodontians were a successful group of rhynchocephalian reptiles that dominated the fossil record of Lepidosauria during the Triassic and Jurassic. Although evidence of extinction is seen at the end of the Laurasian Early Cretaceous, they appeared to remain numerically abundant in South America until the end of the period. Most of the known Late Cretaceous record in South America is composed of opisthodontians, the herbivorous branch of Sphenodontia, whose oldest members were until recently reported to be from the Kimmeridgian–Tithonian (Late Jurassic). Here, we report a new sphenodontian, Sphenotitan leyesi gen. et sp. nov., collected from the Upper Triassic Quebrada del Barro Formation of northwestern Argentina. Phylogenetic analysis identifies Sphenotitan as a basal member of Opisthodontia, extending the known record of opisthodontians and the origin of herbivory in this group by 50 Myr.

scholarly journals First report of Plesiochelys etalloni and Tropidemys langii from the Late Jurassic of the UK and the palaeobiogeography of plesiochelyid turtles

2016 ◽  
Vol 3 (1) ◽  
pp. 150470 ◽  
Author(s):  
Jérémy Anquetin ◽  
Sandra D. Chapman
Keyword(s):  
Late Jurassic ◽  
Western Europe ◽  
Jura Mountains ◽  
Marine Turtles ◽  
Coastal Marine ◽  
French Jura ◽  
Specific Variation ◽  
The Uk ◽  
Clay Formation ◽  
First Time

Plesiochelyidae is a clade of relatively large coastal marine turtles that inhabited the shallow epicontinental seas that covered western Europe during the Late Jurassic. Although the group has been reported from many deposits, the material is rarely identified at the species level. Here, we describe historical plesiochelyid material from the Kimmeridge Clay Formation of England and compare it with contemporaneous localities from the continent. An isolated basicranium is referred to the plesiochelyid Plesiochelys etalloni based notably on the presence of a fully ossified pila prootica. This specimen represents the largest individual known so far for this species and is characterized by remarkably robust features. It is, however, uncertain whether this represents an ontogenetic trend towards robustness in this species, some kind of specific variation (temporal, geographical or sexual), or an abnormal condition of this particular specimen. Four other specimens from the Kimmeridge Clay are referred to the plesiochelyid Tropidemys langii . This contradicts a recent study that failed to identify this species in this formation. This is the first time, to the best of our knowledge, that the presence of Plesiochelys etalloni and Tropidemys langii is confirmed outside the Swiss and French Jura Mountains. Our results indicate that some plesiochelyids had a wide palaeobiogeographic distribution during the Kimmeridgian.

scholarly journals Evidence of macrophagous teleosaurids in the Corallian Group (Oxfordian, Late Jurassic) of the UK

2015 ◽  
Author(s):  
Davide Foffa ◽  
Mark T Young ◽  
Stephen L Brusatte
Keyword(s):  
Fossil Record ◽  
Late Jurassic ◽  
Time Span ◽  
Specific Level ◽  
Northern France ◽  
Lower Jaw ◽  
Abundance And Diversity ◽  
The Uk ◽  
Tooth Count

Teleosaurids were a semi-aquatic group of crocodylomorphs with a fossil record that spanned the Jurassic Period. Abundant specimens are known from Oxford Clay (OCF, Callovian to lower Oxfordian) and Kimmeridge Clay (KCF, Kimmeridgian to lower Tithonian) Formations of the UK, and contemporaneous deposits in northern France. Unfortunately, due to the paucity of material from the intermediate ‘Corallian Gap’(middle to upper Oxfordian), we lack an understanding of how and why teleosaurid taxic abundance and diversity declined from the OCF to the KCF. Our discovery of an incomplete teleosaurid lower jaw from the Corallian of Weymouth (Dorset, UK) begins to help rectify this. The vertically oriented dentition, blunt tooth apices, and intense enamel ornamentation that shifts apical to an anastomosed pattern, and deep reception pits on dentary unambiguously demonstrates the affinity of this specimen with a sub-clade of macrophagous/durophagous teleosaurids ('Steneosaurus' obtusidens + Machimosaurus>). The high symphyseal tooth count allows us to exclude the specimen from M. hugii and M. mosae, but in absence of more diagnostic material we cannot unambiguously assign the specimen to a more specific level. Nevertheless, this specimen represents the first UK mandibular material referable to Teleosauridae from this poorly known time-span.

scholarly journals Evidence of macrophagous teleosaurids in the Corallian Group (Oxfordian, Late Jurassic) of the UK

2015 ◽  
Author(s):  
Davide Foffa ◽  
Mark T Young ◽  
Stephen L Brusatte
Keyword(s):  
Fossil Record ◽  
Late Jurassic ◽  
Time Span ◽  
Specific Level ◽  
Northern France ◽  
Lower Jaw ◽  
Abundance And Diversity ◽  
The Uk ◽  
Tooth Count

Teleosaurids were a semi-aquatic group of crocodylomorphs with a fossil record that spanned the Jurassic Period. Abundant specimens are known from Oxford Clay (OCF, Callovian to lower Oxfordian) and Kimmeridge Clay (KCF, Kimmeridgian to lower Tithonian) Formations of the UK, and contemporaneous deposits in northern France. Unfortunately, due to the paucity of material from the intermediate ‘Corallian Gap’(middle to upper Oxfordian), we lack an understanding of how and why teleosaurid taxic abundance and diversity declined from the OCF to the KCF. Our discovery of an incomplete teleosaurid lower jaw from the Corallian of Weymouth (Dorset, UK) begins to help rectify this. The vertically oriented dentition, blunt tooth apices, and intense enamel ornamentation that shifts apical to an anastomosed pattern, and deep reception pits on dentary unambiguously demonstrates the affinity of this specimen with a sub-clade of macrophagous/durophagous teleosaurids ('Steneosaurus' obtusidens + Machimosaurus>). The high symphyseal tooth count allows us to exclude the specimen from M. hugii and M. mosae, but in absence of more diagnostic material we cannot unambiguously assign the specimen to a more specific level. Nevertheless, this specimen represents the first UK mandibular material referable to Teleosauridae from this poorly known time-span.

scholarly journals A review of the fossil record of non-baenid turtles of the clade Paracryptodira

2019 ◽  
Author(s):  
Walter G. Joyce ◽  
Jérémy Anquetin
Keyword(s):  
North America ◽  
Middle Jurassic ◽  
Fossil Record ◽  
Late Jurassic ◽  
Feeding Strategies ◽  
Aquatic Environments ◽  
Taxonomic Review ◽  
Nomina Invalida ◽  
Nomina Dubia

The fossil record of non-baenid paracryptodires ranges from the Late Jurassic (Kimmeridgian) tothe Paleocene of North America and Europe only. Earlier remains may be present as early as the Middle Jurassic (Bathonian). Only a single dispersal event is documented between the two continents following their breakup during the Cretaceous in the form of the appearance of the Compsemys lineage in the Paleocene of France. Non-baenid paracryptodires were restricted to freshwater aquatic environments, but display adaptations to diverse feeding strategies consistent with generalist, gape-and-suction, and hypercarnivorous feeding. Current phylogenies recognize two species rich subclades within Paracryptodira, Baenidae and Pleurosternidae, which jointly form the clade Baenoidea. A taxonomic review of non-baenid paracryptodires concludes that of 34 named taxa, 11 are nomina valida, 15 nomina invalida, and 8 nomina dubia.

Macroevolutionary trends in the genus Torvoneustes (Crocodylomorpha: Metriorhynchidae) and discovery of a giant specimen from the Late Jurassic of Kimmeridge, UK

2019 ◽  
Vol 189 (2) ◽  
pp. 483-493
Author(s):  
Mark T Young ◽  
Davide Foffa ◽  
Lorna Steel ◽  
Steve Etches
Keyword(s):  
19Th Century ◽  
Body Length ◽  
Late Jurassic ◽  
Occipital Region ◽  
Posterior Surface ◽  
Carotid Canal ◽  
Attachment Sites ◽  
The Uk ◽  
Clay Formation ◽  
The 19Th Century

Abstract The metriorhynchid crocodylomorph fauna of the Late Jurassic Kimmeridge Clay Formation (KCF) of the UK was highly diverse. One genus from this Formation, Torvoneustes, was unique in evolving dentition similar to known chelonivorous crocodylomorphs and enlarged attachment sites for the pterygoideus adductor musculature. Here we report the largest known Torvoneustes specimen, the occipital region of a large cranium that was discovered on the shore of Brandy Bay, Dorset, UK (KCF). We also report three tooth crowns discovered during the 19th century from Oxfordshire that can also be referred to Torvoneustes. The partial braincase is unique in having: verticalized basioccipital tuberosities that have thickened ventral margins, the notch between the basioccipital tuberosities is a narrow inverted ‘U’-shape and a subrectangular-shaped carotid canal foramina. The presence of ‘occipital fossae’ (deep concavities with the hypoglossal foramina in their dorsomedial corners) and carotid foramina with raised rims relative to the basioccipital posterior surface, allow us to refer it to Torvoneustes. Although incomplete, the exceptional size of the specimen demonstrates that Torvoneustes attained larger body lengths than previously supposed (3.7–4.7 m). Comparing the dimensions of this specimen to other metriorhynchids suggests that at least some Torvoneustes specimens rivalled Plesiosuchus manselii in body length.

A new marine clupeoid fish from the Lower Cretaceous of the Sergipe-Alagoas Basin, northeastern Brazil

Zootaxa ◽  
2009 ◽  
Vol 2164 (1) ◽  
pp. 21-32 ◽  
Author(s):  
FRANCISCO J. DE FIGUEIREDO
Keyword(s):  
Fossil Record ◽  
Upper Cretaceous ◽  
Democratic Republic ◽  
Democratic Republic Of Congo ◽  
Axial Skeleton ◽  
Northeastern Brazil ◽  
Unique Combination ◽  
Caudal Vertebrae ◽  
Clupeoid Fish ◽  
Marine Deposit

Clupeomorph fishes are largely diversified and widespread in Cretaceous strata of northeastern Brazil. They are represented by basal clupeiforms, †ellimmichthyiforms, and advanced clupeoids. In this paper, a new clupeoid fish, †Nolfia riachuelensis sp. nov., is described based on a specimen found in marine shale yielded in the Taquari Member (Albian) of Riachuelo Formation, Sergipe-Alagoas Basin. Although partially preserved (most of skull is lacking), the fish shows many informative characters, particularly in the axial skeleton. The fish is morphologically very similar to †Nolfia kwangoensis, a clupeoid fish originally described from marine deposit from the Upper Cretaceous (Cenomanian) of Kipala, Democratic Republic of Congo, with which it shares: 18 caudal vertebrae; long and cylindrical pleural ribs; posteriormost pleural ribs supported by long parapophyses and gradually decreasing in size posteriorly; very reduced ural centra; presence of long and distally congruent neural spines of third, second, and first preural centra; three uroneural bones (the first probably forming the pleurostyle). Otherwise, †Nolfia riachuelensis sp. nov. differs from other clupeomorphs by a unique combination of features. The number of supraneural bones, aligned rod-like postcleithra, less than 30 rays in the anal fin, and derived absence of dorsal scutes indicate its placement within Clupeidae. As far as is known, †Nolfia riachuelensis sp. nov. is the most ancient clupeoid fish known from the fossil record.

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