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

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.

2015 ◽  
Author(s):  
Davide Foffa ◽  
Mark T Young ◽  
Stephen L Brusatte

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.


2015 ◽  
Author(s):  
Davide Foffa ◽  
Mark T Young ◽  
Stephen L Brusatte

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.


2015 ◽  
Author(s):  
Davide Foffa ◽  
Mark T Young ◽  
Stephen L Brusatte ◽  
Lorna Steel

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.


2015 ◽  
Author(s):  
Davide Foffa ◽  
Mark T Young ◽  
Stephen L Brusatte ◽  
Lorna Steel

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.


2019 ◽  
Vol 189 (2) ◽  
pp. 483-493
Author(s):  
Mark T Young ◽  
Davide Foffa ◽  
Lorna Steel ◽  
Steve Etches

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.


2016 ◽  
Vol 3 (1) ◽  
pp. 150470 ◽  
Author(s):  
Jérémy Anquetin ◽  
Sandra D. Chapman

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.


PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6646 ◽  
Author(s):  
Davide Foffa ◽  
Michela M. Johnson ◽  
Mark T. Young ◽  
Lorna Steel ◽  
Stephen L. Brusatte

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.


2007 ◽  
Vol 20 (1) ◽  
pp. 21-32 ◽  
Author(s):  
Vanessa C. Thorn

AbstractPhytoliths in the modern vegetation of sub-Antarctic Campbell Island are compared with those in the soil beneath to assess the accuracy of vegetation reconstructions made from dispersed phytolith assemblages. The soil phytoliths alone suggest the source vegetation is a grassland association for all study sites, which reflects none of the herb, fern or shrub component of the overlying vegetation. It is concluded that at this locality dispersed phytoliths on their own are not reliable indicators of source vegetation and should be used with caution in this context for palaeoecological studies. However, they can provide useful botanical information where all other organic material is absent. With further research, based on the abundance and diversity of Poaceae phytoliths observed in this and other studies, dispersed phytoliths from the fossil record have the potential to contribute significantly to the understanding of grassland ecosystem development in the geological past.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Dan G. O’Neill ◽  
Rowena M.A. Packer ◽  
Peter Francis ◽  
David B. Church ◽  
Dave C. Brodbelt ◽  
...  

Abstract Background The French Bulldog is a highly popular dog breed but is linked with many serious health issues. A holistic view of breed health in French Bulldogs would assist efforts to appreciate the overall health strengths and weaknesses in the French Bulldog and to take appropriate steps to mitigate these. Based on random sampling of French Bulldogs and non-French Bulldogs under primary veterinary care during 2016 within the VetCompass Programme, a cohort study design was used to estimate the one-year (2016) period prevalence of the most commonly diagnosed disorders in each group. Risk factor analysis used multivariable logistic regression modelling methods. Results The analysis included 2,781 French Bulldogs and 21,850 non-French Bulldogs. French Bulldogs were younger (1.51 years, IQR 0.86 – 2.77 vs. 4.48 years, IQR 1.94 – 8.14) (p < 0.001) and lighter (12.45 kg, IQR 11.00 – 14.03 versus 13.80 kg, IQR 8.10 – 25.12) (p < 0.001) than non-French Bulldogs. Of 43 common specific-level disorders across both groups, French Bulldogs had significantly increased adjusted odds of 20/43 (46.5 %) disorders and significantly reduced adjusted odds of 11/43 (25.6 %) disorders compared to non-French Bulldogs. Highly predisposed disorders in French Bulldogs included stenotic nares (OR 42.14; 95 % CI 18.50 to 95.99; p < 0.001), Brachycephalic Obstructive Airway Syndrome (OR 30.89; 95 % CI 20.91 to 45.64; p < 0.001), aural discharge (OR 14.40; 95 % CI 9.08 to 22.86; p < 0.001), skin fold dermatitis (OR 11.18; 95 % CI 7.19 to 17.40; p < 0.001) and dystocia (OR 9.13; 95 % CI 5.17 to 16.13; p < 0.001). At a grouped-level of diagnostic precision, French Bulldogs had increased adjusted odds of 12/32 (37.5 %) disorders and reduced adjusted odds of 6/32 (18.8 %) disorders compared to non-French Bulldogs. Conclusions These results identified ultra-predispositions with worryingly higher odds in French Bulldogs for several disorders, suggesting that the health of French Bulldogs has diverged substantially from, and may be lower than, the health of the wider non-French Bulldog population. Many of these predispositions are closely associated with the conformational extremes that define the French Bulldog breed. Shifting the typical conformation of the French Bulldog population towards a more moderate phenotype is proposed as a logical opportunity to reduce the serious health issues endemic in the French Bulldog breed.


Fossil Record ◽  
1999 ◽  
Vol 2 (1) ◽  
pp. 25-61 ◽  
Author(s):  
W.-D. Heinrich

Tendaguru is one of the most important dinosaur localities in Africa. The Tendaguru Beds have produced a diverse Late Jurassic (Kimmeridgian to Tithonian) dinosaur assemblage, including sauropods (<i>Brachiosaurus, Barosaurus, Dicraeosaurus, Janenschia</i>), theropods (e.g., <i>Elaphrosaurus, Ceratosaurus, Allosaurus</i>), and ornithischians (<i>Kentrosaurus, Dryosaurus</i>). Contrary to the well studied skeletal anatomy of the Tendaguru dinosaurs, the available taphonomic information is rather limited, and a generally accepted taphonomic model has not yet been established. Assessment of unpublished excavation sketches by the German Tendaguru expedition (1909–1913) document bone assemblages of sauropod and ornithischian dinosaurs from the Middle Saurian Bed, Upper Saurian Bed, and the Transitional Sands above the <i>Trigonia smeei</i> Bed, and shed some light on the taphonomy of the Tendaguru dinosaurs. Stages of disarticulation range from incomplete skeletons to solitary bones, and strongly argue for carcass decay and post-mortem transport prior to burial. The sauropod bone accumulations are dominated by adult individuals, and juveniles are rare or missing. The occurrence of bones in different superimposed dinosaur-bearing horizons indicates that skeletal remains were accumulated over a long time span during the Late Jurassic, and the majority of the bone accumulations are probably attritional. These accumulations are likely to have resulted from long-term bone imput due to normal mortality events caused by starvation, seasonal drought, disease, old age and weakness. The depositional environment of the Middle and Upper Saurian Bed was mainly limnic to brackish in origin, while the palaeoenvironment of the Transitional Sands was marginal marine. <br><br> Tendaguru zählt zu den bedeutendsten Dinosaurier-Lagerstätten Afrikas. Aus den Tendaguru-Schichten sind zahlreiche Skelettreste von Sauropoden (<i>Brachiosaurus, Barosaurus, Dicraeosaurus, Janenschia</i>), Theropoden (z.B. <i>Elaphrosaurus, Ceratosaurus, Allosaurus</i>) und Ornithischiern (<i>Kentrosaurus, Dryosaurus</i>) geborgen worden. Sie stammen aus der späten Jura-Zeit (Kimmeridge — Tithon). Während der Skelettbau der Tendagurusaurier gut untersucht ist, wirft die Taphonomie des Sauriervorkommens von Tendaguru noch immer Fragen auf. Unklar ist bislang, wie die enormen Anreicherungen von Dinosaurierknochen in den Tendaguru-Schichten zustandekamen. Unveröffentlichte Grabungsskizzen der Deutschen Tendaguru Expedition (1909–1913) erweitern unsere Kenntnisse über die Taphonomie der Tendagurusaurier. In den ausgewerteten Grabungsskizzen sind Knochenansammlungen von Sauropoden und Ornithischiern aus dem Mittleren und Oberen Sauriermergel sowie aus den Übergangsschichten über der <i>Trigonia smeei</i>-Schicht dokumentiert. Die Lage und der Erhaltungszustand der Funde lassen auf erheblichen Zerfall der Kadaver und post-mortalen Transport von Skelettelementen vor der Einbettung schließen. Das Vorkommen von Saurierknochen in mehreren übereinanderliegenden Profilabschnitten der Tendaguru-Schichten zeigt, daß Skelettreste während der späten Jura-Zeit über einen längeren Zeitraum hinweg akkumuliert wurden. Die Ansammlungen von Skelettresten gehen wahrscheinlich auf „normale” Sterbe-Ereignisse zurück, wie z. B. Verhungern, Verdursten, Kankheit, Altersschwäche und jahreszeitliche Dürre. Als Ablagerungsraum der Mittleren und Oberen Saurierschicht kommt ein küstennaher limnischer, zeitweise wohl auch brackischer Küstenstreifen in Betracht. Die knochenführenden Übergangsschichten unter- und oberhalb der Saurierschichten sind randlich marine Ablagerungen. <br><br> doi:<a href="http://dx.doi.org/10.1002/mmng.1999.4860020102" target="_blank">10.1002/mmng.1999.4860020102</a>


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