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This paper describes a fragment of a sub-adult specimen of Steneosaurus cf. heberti (Crocodylia, Thalattosuchia, Teleosauridae) found in the Callovian of the "Vaches Noires" (Normandy, France). The small size of the specimen makes it particularly interesting, as few Teleosauridae of this size have been found in the Callovian in Europe. A recent revision, based solely on the existing material of the genus Steneosaurus, proposes that the genus be abandoned for ten other monospecific genera. We intend to show that in addition to this being a misinterpretation, it also skews diagnoses, such as the one presented here. A reassessment of the paleoecology of Teleosauridae is also provided., Il est décrit ici un fragment de spécimen subadulte de Steneosaurus cf. heberti (Crocodylia, Thalattosuchia, Teleosauridae) trouvé dans le Callovien des Vaches Noires (Normandie, France). L’intérêt de ce spécimen réside dans sa petite taille car peu de Teleosauridae de cette dimension ont été trouvés dans le Callovien en Europe. Récemment une révision basée uniquement sur le matériel existant du genre Steneosaurus, propose son abandon pur et simple pour dix autres genres monospécifiques. Cette proposition repose sur une interprétation incomplète du code de nomenclature et provoque une instabilité de ce genre créé il y a deux siècles. Une réinterprétation de la paléoécologie des Teleosauridae est aussi proposée.

The Jurassic was a key interval for the evolution of dinosaurs, crocodylomorphs and many other vertebrate groups. In recent years, new vertebrate fossils have emerged from the Early–Middle Jurassic of the Isle of Skye, Scotland; however, much more is known about Skye9s dinosaur fauna than its crocodylomorphs. Here we report new crocodylomorph material collected from Jurassic marine deposits at Prince Charlie9s Cave on the NE coast of Skye. The specimen is a small cobble containing postcranial elements from an individual that is considerably larger in size than previous crocodylomorphs described from Skye. Based on features of the vertebrae and osteoderms, the specimen is assigned to Thalattosuchia, an extinct clade of semi-aquatic/pelagic crocodylomorphs. Specifically, the sub-circular and bean-shaped pit ornamentation on the dorsal surface of the osteoderms in alternating rows suggests affinities with the semi-aquatic lineage Teleosauroidea. Although the ornamentation pattern on the osteoderms is most similar to Macrospondylus (‘Steneosaurus’) bollensis, we conservatively assign the specimen to Teleosauroidea indeterminate. Regardless of its precise affinities and fragmentary nature, the specimen is the first thalattosuchian discovered in Scotland and is the most northerly reported Jurassic thalattosuchian globally, adding to our understanding of the palaeobiogeography and evolution of this group. Thematic collection: This article is part of the Early Career Research collection available at: https://www.lyellcollection.org/cc/SJG-early-career-research

Teleosauroidea is a clade of ancient crocodylomorphs that were integral components of coastal marine environments throughout the Jurassic. For nearly two centuries, one of the most familiar genera of teleosauroids has been Steneosaurus, encompassing nearly every teleosauroid species at some point. However, no type species has been designated for Steneosaurus under ICZN Code rules; the type specimen of the presumed type species S. rostromajorGeoffroy Saint-Hilaire, 1825 (MNHN.RJN 134c-d) is a chimera that has been largely neglected in the literature. Moreover, there is confusion as to which teleosauroid species it pertains to, and the genus Steneosaurus is often recovered as paraphyletic or polyphyletic in phylogenetic analyses. As such, the validity of Steneosaurus is uncertain. Here we formally designate S. rostromajor as the type species of Steneosaurus, designate a lectotype and re-evaluate MNHN.RJN 134c-d. We compare it with several well-known teleosauroids, including Lemmysuchus and ‘S.’ edwardsi. Due to lack of autapomorphic characters, poor preservation and a tortured taxonomic history, we find MNHN.RJN 134c-d to be an undiagnostic and unreliable specimen. Thus, we consider S. rostromajor as a nomen dubium and propose that the genus Steneosaurus is undiagnostic. This has profound implications for teleosauroid phylogenetics, which we will clarify in an upcoming paper.

Teleosaurids were a clade of crocodylomorphs that attained near-global distribution during the Jurassic Period. Within Teleosauridae, one particular sub-clade of durophagous/macrophagous taxa achieved large body sizes and were apex predators in shallow marine environments during the Late Jurassic and Early Cretaceous in Europe and around the coast of the Tethys Seaway. Unfortunately, the origins of this clade are still poorly understood. ‘Steneosaurus’ obtusidens is a little-studied macrophagous species from the Oxford Clay Formation (Callovian, Middle Jurassic) of the UK and near Migne-les-Lourdines (Middle Callovian) in France. Despite being considered a sister taxon of the Late Jurassic taxon Machimosaurus, the taxonomy of ‘S.’ obtusidens remains unclear. Although three different synonymies have been proposed (variously a subjective synonym of other taxa), these taxonomic hypotheses have not been based on detailed anatomical comparisons and thus have not been tested. Here, we re-describe the holotype of ‘S.’ obtusidens, demonstrate that it is indeed a valid taxon, restrict the referred specimens to a fragmentary skeleton, nearly complete skull, and partial rostrum, and establish a new monotypic genus, Lemmysuchus. Our re-description reveals five autapomorphies for Lemmysuchus obtusidens and nine apomorphic characters that support the tribe Machimosaurini (Lemmysuchus + Machimosaurus).

We report here finds of thalattosuchians from Western Carpathians. The material consists of two isolated teeth from two different localities of the Pieniny Klippen Belt. The material represents the first evidence of the occurrence of both clades Teleosauridae and Metriorhynchidae in Slovakia. The first, a small tooth comes from the locality Beňatina and is dated early Middle Jurassic (Aalenian). Identification of the specimen shows it belongs to a longirostrine teleosaurid, possibly to Steneosaurus. Teleosaurids were largely restricted to lagoonal/near-shore environments. Their limbs allow them to support and walk on land. Regarding that fact, the presence of this taxon in Beňatina might be an indication of terrestrial land in the nearby area and shows a location of epicontinental seaways. A second larger tooth was found in the Upper Jurassic (Tithonian) sediments of the locality Kyjov, and is tentatively allocated in the genus Plesiosuchus. The members of Plesiosuchina are known in England, Franc...

Marine crocodylomorphs were particularly abundant in Europe during the Middle Jurassic, but were very scarce in Africa. New finds of thalattosuchian cranial remains in Morocco suggest that this scarcity is probably related to poor sampling rather than original diversity. These remains pertain to the coastal thalattosuchians, the teleosauroids, and particularly to the clade grouping the blunt-toothed ‘Steneosaurus’ obtusidens and the genus Machimosaurus. A new tribe is erected grouping these two taxa: Machimosaurini. Until now the machimosaurins have been known from the middle Callovian. The new material extends the presence of this group further back to the lower Bathonian, nearly 5 myr earlier. The machimosaurins are the only teleosauroid group that has been recently reviewed, and the difference between the revised diversity provided herein and that previously reported is large. A review of other teleosauroids and clear establishment of their phylogenetic relationships are also likely to have considerable impact on their observed diversity. So, until a complete review of the teleosauroids is carried out, the results of crocodylomorph diversity analyses should be treated with caution.

Modern crocodylians are a morphologically conservative group, but extinct relatives (crocodylomorphs) experimented with a wide range of diets, behaviors, and body sizes. Among the most unusual of these fossil groups is the thalattosuchians, an assemblage of marine-dwellers that transitioned from semiaquatic species (teleosaurids and kin) into purely open-ocean forms (metriorhynchids) during the Jurassic and Cretaceous Periods (ca 191-125 million years ago). Thalattosuchians can give insight into the origin of modern crocodylian morphologies and how anatomy and behavior change during a major evolutionary transition into a new habitat. Little is known, however, about their brains, sensory systems, cranial sinuses, and vasculature. We here describe the endocranial anatomy of a well-preserved specimen of the Jurassic semiaquatic teleosaurid Steneosaurus cf. gracilirostris using X-ray micro-CT. We find that this teleosaurid still had an ear well attuned to hear on land, but had developed large internal carotid and orbital arteries that likely supplied salt glands, previously thought to be present in only the fully pelagic metriorhynchids. There is no great gulf in endocranial anatomy between this teleosaurid and the metriorhynchids, and some of the features that later permitted metriorhynchids to invade the oceanic realm were apparently first developed in semiaquatic taxa. Compared to modern crocodylians, Steneosaurus cf. gracilirostris has a more limited set of pharyngotympanic sinuses, but it is unclear whether this relates to its aquatic habitat or represents the primitive condition of crocodylomorphs that was later elaborated. Anat Rec, 299:1511-1530, 2016. © 2016 Wiley Periodicals, Inc.

Teleosaurids were a clade of marine crocodylomorphs that were globally distributed during the Jurassic Period. They evolved a wide range of body sizes, from small (?2–3?m) to very large (>?9?m). Until now, the largest known Middle Jurassic teleosaurid was ‘Steneosaurus’?obtusidens, from the Oxford Clay Formation of the UK. Here, we re-examine a very large Oxford Clay specimen (ilium, ischium, and femur) that had been tentatively attributed to ‘S.’?obtusidens. Based on comparative anatomical study with the ‘S.’?obtusidens holotype and referred specimens of Steneosaurus?edwardsi and Steneosaurus?leedsi, we conclude that this very large individual actually pertains to S.?edwardsi. Based on comparisons with the Machimosaurus?mosae neotype (which has a complete femur and skeleton), we estimate a total length in excess of 7?m for this large S.?edwardsi individual, making it the largest known Middle Jurassic teleosaurid. Therefore, along with the closely related genus Machimosaurus, this clade of large-bodied Middle–Late Jurassic teleosaurids were the largest species during the first 100 million years of crocodylomorph evolution.

Teleosauroids were a clade of semi-marine crocodylomorphs that attained near-global distribution during the Jurassic Period. They were particularly common during the Toarcian (Early Jurassic) and are well documented throughout the UK and Germany. However, Toarcian teleosauroids discovered in Luxembourg have been little studied and rarely discussed in the scientific literature. Here we present a comprehensive catalogue of Luxembourg thalattosuchian specimens, including nine teleosauroids (all from the Toarcian) and five Thalattosuchia indeterminate (four from the Toarcian and one from the Bajocian), many of which are noted in the literature for the first time. We describe these specimens and identify two distinct genera (Steneosaurus and Platysuchus) as present in the sample as well as three, or possibly four, distinct species. This represents a high diversity of teleosauroid taxa (both common and rare forms) from the Toarcian rarely seen elsewhere in the world.

Thalattosuchia was a diverse clade of marine crocodylomorphs known from the Early Jurassic to the Early Cretaceous. Recent studies have hypothesized that their extinction was two-phased: (1) habitat loss near/at the Jurassic-Cretaceous boundary heavily reduced their morphofunctional diversity, particularly in Europe, while (2) climate change and a shift in marine fauna during the Early Cretaceous (either at the Valanginian-Hauterivian boundary or during the early Hauterivian) finished off the already stressed clade. Unfortunately, the Cretaceous fossil record of thalattosuchians is poor, with only one putative “teleosaurid” specimen and approximately ten metriorhynchid specimens. Here we re-describe the youngest known teleosaurid from the Cretaceous (Valanginian of south-eastern France). Originally considered to be a teleosaurid (possibly Steneosaurus), we demonstrate that it belongs to Metriorhynchidae, and a newly discovered subclade, Plesiosuchina. It differs from Plesiosuchus in the pattern of tooth enamel ornamentation and the variation in dentary alveoli size. Referring this specimen to Metriorhynchidae means there are no definitive Cretaceous teleosaurid specimens. Furthermore, it suggests that both durophagous and piscivorous teleosaurids became extinct at the end of the Jurassic. Interestingly, this is the fourth metriorhynchid lineage known to cross the Jurassic-Cretaceous boundary. As such, it would appear that the two thalattosuchian families responded very differently to the lowering sea levels at the end of the Jurassic: teleosaurids possibly became extinct, while metriorhynchids were seemingly unaffected.

A Jacques-Amand Eudes-Deslongchamps' unpublished work on marine crocodyliforms from the Jurassic of Normandy (France). An unpublished manuscript by Jacques-Amand Eudes-Deslongchamps describes the remains of two species of fossil crocodyliforms attributed to the genus Steneosaurus Geoffroy Saint-Hilaire, 1825. It is demonstrated that these notes give detailed explanations of three engravings that were executed under the direction of Etienne Geoffroy Saint-Hilaire in 1831. These plates represent remains of Steneosaurus megistorhynchus Geoffroy Saint-Hilaire, in J.-A. Eudes-Deslongchamps, 1866 and Teleidosaurus calvadosii (J.-A. Eudes-Deslongchamps, 1866). Written before 1837 and likely between June 1831 and June 1832, this work would be the oldest study on thalattosuchians from Normandy, known to date, by Jacques-Amand Eudes-Deslongchamps. This document prefigures the quality of his future works on fossil crocodyliforms that he published more than thirty years later. An extensive excerpt from this ...

The fourth complete skull of the marine crocodilian Machimosaurus von Meyer, 1837 is hereby described together with an associated complete mandible and disarticulated postcranial elements from the Kimmeridgian of Neuffen, Germany. Although the genus has been described fairly recently on the basis of two nearly complete skulls, their state of preservation did not allow a thorough examination of the entire skull anatomy. Here, we add new information with the description of nicely preserved cranial and mandibular elements of a single individual attributable to Machimosaurus hugii von Meyer, 1837. The diagnosis is updated for the genus and for the species M. hugii and challenges the validity of the second species M. mosae (Liénard, 1876). Moreover, previous assumption that Steneosaurus obtusidens Andrews, 1913 is a junior synonym of Machimosaurus hugii is not supported by our observations. Notably, M. hugii differs from S. obtusidens by a lower tooth count, the morphology of the dentition, the shape of the supratemporal fenestrae and the absence of an antorbital fenestra. Comparative anatomy and a phylogenetic analysis show that Machimosaurus is more closely related to the genus Steneosaurus than to Teleosaurus cadomensis (Lamouroux, 1820). doi:10.1002/mmng.201300009

A taphonomic model is erected for a dataset of 19 Steneosaurus (Mesoeucrocodylia; Thalattosuchia) from the Toarcian Posidonienschiefer Formation (Lower Jurassic) of Germany. These were deposited in a quiet-water, marine, basin. Their taphonomy is compared with that of an additional seven thalattosuchians from other Jurassic localities (Peterborough and Yorkshire, UK; Nusplingen, Germany). The skeletal taphonomy of the specimens is assessed in terms of the articulation and completeness of nine skeletal units. Steneosaurus from the Posidonienschiefer Formation exhibit variable levels of articulation in the nine units. Completeness also varies but the head, neck and dorsal units are complete in all specimens. Carcasses reached the sediment–water interface shortly after death. Loss of fidelity occurred primarily as individuals lay on the sediment, and disarticulated elements tended to remain in the vicinity of the carcass. Those elements absent from specimens are the smaller, more distal, bones of the limbs and tail; these were removed preferentially by weak bottom currents. Smaller specimens are consistently less complete. Specimens from other localities broadly follow the same taphonomic pathway, suggesting a consistent pattern for the skeletal taphonomy of the carcasses of marine crocodiles. Loss of completeness in some specimens is more exacerbated, the result of stronger current activity at the sediment–water interface.

The holotype and referred specimens of Geosaurus giganteus, a metriorhynchid crocodile from the Tithonian (Upper Jurassic) of Germany, is redescribed, along with a historical overview of the genus and species. This taxon is unique among metriorhynchids as its serrated, strongly lateromedially compressed dentition is arranged as opposing blades, suggesting it was adapted to efficiently slice through fleshy prey. A new phylogenetic analysis of Crocodylomorpha is presented, which finds G. giganteus to be nested within what is currently considered Dakosaurus, whereas the other species currently assigned to Geosaurus form a clade with Enaliosuchus and the holotype of Cricosaurus. The phyletic relationship of G. giganteus with other metriorhynchids indicates that the current definition of the genus Geosaurus is polyphyletic, and that the inclusion of subsequent longirostrine species to this genus is in error. The re-analysis presented herein demonstrates Geosaurus to be composed of three species sensu stricto. The appropriate taxonomic amendments to the Metriorhynchidae are also provided. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 157, 551–585.

Several Teleosaurus skulls were described during the nineteenth century. Unfortunately, all skulls from this genus were destroyed during World War II. The only available skull is currently preserved in the MNHN. Thanks to a new preparation, new anatomical features can be seen, such as the morphology of the nasal cavity, the external otic recess, and the distribution of the foramina for the cranial nerves. A phylogenetic analysis is presented, including 14 thalattosuchian taxa. This analysis has generated four equally most parsimonious trees, where the thalattosuchians are closely related to the pholidosaurids and dyrosaurids, forming a longirostrine taxa. These relationships have been often considered to be based on homoplasies, related to the longirostrine morphology. This is also suggested herein, as the deletion of the longirostrine dependant characters or of the most longirostrine thalattosuchians in the analysis provide a consensus tree where thalattosuchians are basal crocodyliforms, a resu...

Four examples of the Callovian bivalve Gryphaea (Bilobissa) lituola Lamarck, 1819 from the Oxford Clay Formation (Stewartby Member) of South Cave Station Quarry, Yorkshire display puncture wounds and indentations produced by an unknown predator. The specimens, which came from beds of the Athleta Zone, are described and figured. Three groups of durophagous (shell-crushing) predators which possessed the claws or teeth required to inflict such wounds (crustaceans, fish and marine reptiles) are considered. Other possible causes of the damage, such as taphonomic processes and boring by predatory organisms, are examined and rejected. It is suggested, rather tentatively, that the wounds were produced by the actions of the marine crocodilian Steneosaurus durobrivensis .

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.

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.

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.

The fossil remains of two small reptiles recently discovered in the Sogno Formation (Lower Toarcian) near Cesana Brianza (Lecco Province), represent the first mesoeucrocodylians reported for Lombardy and some of the few Jurassic reptiles from Italy. Due to the absence of diagnostic skeletal elements (the skulls are lacking), it is not possible to refer the new specimens at genus level with confidence. Although the well developed dermal armour would characterise Toarcian thalattosuchians of the genera Steneosaurus (Teleosauridae) and Pelagosaurus (Metriorhynchidae), the peculiar morphology of the osteoderms allow to tentatively refer the remains to the latter taxon (cf. Pelagosaurus sp.). The small size, along with the opening of the neurocentral vertebral sutures and, possibly, the non sutured caudal pleurapophyses, indicate that the specimens were morphologically immature at death. These “marine crocodiles” confirm the affinities between the fauna of the Calcare di Sogno Formation and coeval outcrops of central Europe that also share the presence of similar fishes and crustaceans.

Large endocranial features are revealed in a three-dimensionally preserved specimen of the thalattosuchian crocodile Steneosaurus pictaviensis. Structures found on an endocast indicate the presence of the same venous blood system, although much enlarged, as found within the cranial cavity of modern crocodilians. An exceptionally large longitudinal dorsal blood sinus forms an expanded torcular herophili above the junction of the midbrain and hindbrain. The venous canals entering the posterodorsal part of the torcular herophili are the capiti dorsalis, which drain blood from the temporal and occipital musculature, entering the braincase in this region as in many extant and extinct Archosauria.

In 1787, a fragmentary fossil skull of a crocodylian was discovered in the Altopiano dei Sette Comuni (Veneto, Northern Italy). In 1883, the specimen was referred to a new species of the teleosauroid Steneosaurus, S. barettoni. In this study, the specimen is redescribed and its taxonomic status reviewed. S. barettoni fails to conform to Article 12 of the International Code of Zoological Nomenclature and is considered as a nomen nudum. The specimen lacks synapomorphies of both Teleosauroidea and Steneosaurus, whereas it is referred to Metriorhynchidae based on the presence of an elongate median depression between the dorsal surface of nasals, and a large teardrop-shaped prefrontal that is expanded laterally. The combination of cranial and dental features present in this specimen supports its referral to Neptunidraco, an interpretation that adds new information on the morphology of the Italian metriorhynchid. Although total evidence analysis placed Neptunidraco as a basal divergence among Geosaurinae, it independently evolved some craniomandibular features previously considered exclusive of the macrophagous Geosaurini. This specimen is historically relevant because it may represent the first metriorhynchoid found worldwide.

Teleosauridae was a group of largely marine Mesozoic crocodylomorphs, typically considered as akin to “marine gavials” due to their elongate, tubular, polydont rostra that are indicative of a piscivorous diet. Here we show that these extinct crocodylomorphs were more anatomically, and perhaps ecologically, varied than previously thought. We report the first evidence of denticles in a teleosaurid tooth, revealed by scanning electron microscopic (SEM) analysis of a tooth from the holotype of “Steneosaurus” obtusidens. These denticles are cryptic, because they are microscopic, not contiguous along the carinae (instead forming short series), and are detectable only using SEM. This incipient denticle morphology is similar to that recently discovered in a closely related group of marine crocodylomorphs, the Metriorhynchidae. In particular, the denticulation morphology of “Steneosaurus” is similar to that of the geosaurin metriorhynchid Torvoneustes, indicating that these two taxa may have employed similar feeding styles and that “S.”obtusidens may have been a nearshore ecological analogue to the more offshore, fast-swimming geosaurins. Previous authors have considered “S.” obtusidens and Machimosaurus to be durophagous, but the discovery of denticulated teeth indicates that they had a more varied diet and feeding style, and included flesh slicing as part of their feeding toolkit. It is currently unknown how extensive denticulate carinae may be in Teleosauridae, and we hypothesise that cryptic denticles may also be present in other marine crocodylomorphs once they are subjected to SEM study.

Background: Dakosaurus and Plesiosuchus are characteristic genera of aquatic, large-bodied, macrophagous metriorhynchid crocodylomorphs. Recent studies show that these genera were apex predators in marine ecosystems during the latter part of the Late Jurassic, with robust skulls and strong bite forces optimized for feeding on large prey. Methodology/Principal Findings: Here we present comprehensive osteological descriptions and systematic revisions of the type species of both genera, and in doing so we resurrect the genus Plesiosuchus for the species Dakosaurus manselii. Both species are diagnosed with numerous autapomorphies. Dakosaurus maximus has premaxillary 'lateral plates'; strongly ornamented maxillae; macroziphodont dentition; tightly fitting tooth-to-tooth occlusion; and extensive macrowear on the mesial and distal margins. Plesiosuchus manselii is distinct in having: non-amblygnathous rostrum; long mandibular symphysis; microziphodont teeth; tooth-crown apices that lack spalled surfaces or breaks; and no evidence for occlusal wear facets. Our phylogenetic analysis finds Dakosaurus maximus to be the sister taxon of the South American Dakosaurus andiniensis, and Plesiosuchus manselii in a polytomy at the base of Geosaurini (the subclade of macrophagous metriorhynchids that includes Dakosaurus, Geosaurus and Torvoneustes). Conclusions/Significance: The sympatry of Dakosaurus and Plesiosuchus is curiously similar to North Atlantic killer whales, which have one larger 'type' that lacks tooth-crown breakage being sympatric with a smaller 'type' that has extensive crown breakage. Assuming this morphofunctional complex is indicative of diet, then Plesiosuchus would be a specialist feeding on other marine reptiles while Dakosaurus would be a generalist and possible suction-feeder. This hypothesis is supported by Plesiosuchus manselii having a very large optimum gape (gape at which multiple teeth come into contact with a prey-item), while Dakosaurus maximus possesses craniomandibular characteristics observed in extant suction-feeding odontocetes: shortened tooth-row, amblygnathous rostrum and a very short mandibular symphysis. We hypothesise that trophic specialisation enabled these two large-bodied species to coexist in the same ecosystem., Facultad de Ciencias Naturales y Museo

Machimosauruswas a large-bodied durophagous/chelonivorous genus of teleosaurid crocodylomorph that lived in shallow marine and brackish ecosystems during the Late Jurassic. Among teleosaurids,Machimosaurusand its sister taxon ‘Steneosaurus’obtusidensare characterized by having foreshortened rostra, proportionally enlarged supratemporal fenestrae and blunt teeth with numerous apicobasal ridges and a shorter anastomosed ridged pattern in the apical region. A recent study on ‘S.’obtusidensdentition found both true denticles and false serrations (enamel ridges which contact the carinae). Here, we comprehensively describe and figure the dentition ofMachimosaurus, and find thatMachimosaurusbuffetautiandMachimosaurus hugiihave four types of serration or serration-like structures, including both denticles and false denticles on the carinae. The denticles are irregularly shaped and are not always discrete units, whereas the false denticles caused by the interaction between the superficial enamel ridges and the carinae are restricted to the apical region. Peculiarly, the most ‘denticle-like’ structures are discrete, bulbous units on the apicobasal and apical anastomosed ridges ofM. hugii. These ‘pseudo-denticles’ have never, to our knowledge, previously been reported among crocodylomorphs, and their precise function is unclear. They may have increased the surface area of the apical region and/or strengthened the enamel, both of which would have been advantageous for a durophagous taxon feeding on hard objects such as turtles.

Machimosauruswas a large-bodied genus of teleosaurid crocodylomorph, considered to have been durophagous/chelonivorous, and which frequented coastal marine/estuarine ecosystems during the Late Jurassic. Here, we revise the genus based on previously described specimens and revise the species within this genus. We conclude that there were three EuropeanMachimosaurusspecies and another taxon in Ethiopia. This conclusion is based on numerous lines of evidence: craniomandibular, dental and postcranial morphologies; differences in estimated total body length; geological age; geographical distribution; and hypothetical lifestyle. We re-diagnose the type speciesMachimosaurus hugiiand limit referred specimens to only those from Upper Kimmeridgian–Lower Tithonian of Switzerland, Portugal and Spain. We also re-diagnoseMachimosaurus mosae, demonstrate that it is an available name and restrict the species to the uppermost Kimmeridgian–lowermost Tithonian of northeastern France. We re-diagnose and validate the speciesMachimosaurus nowackianusfrom Harrar, Ethiopia. Finally, we establish a new species,Machimosaurus buffetauti, for the Lower Kimmeridgian specimens of France and Germany (and possibly England and Poland). We hypothesize thatMachimosaurusmay have been analogous to the Pliocene–Holocene genusCrocodylusin having one large-bodied taxon suited to traversing marine barriers and additional, geographically limited taxa across its range.

SUMMARY A new specimen of a Mesosuchian crocodile is described from a loose boulder found on the foreshore north of Port Mulgrave on the Yorkshire coast. From a consideration of the associated ammonite and bivalve fauna, the provenance of the boulder is shown to be the top of the Jet Rock ( Harpoceras elegans horizon, upper one third of the exaratum Subzone). The vertebrate material is disarticulated and incomplete, and is referred to Steneosaurus bollensis. Although the species is well known from the equivalent horizon in the classic Toarcian faunas of Holzmaden, south-west Germany, most Yorkshire crocodilian material comes from well above this level and this is the first properly documented record of a crocodile from the Jet Rock (lower part of the Jet Rock Member) of the Yorkshire Coast. The specimen is described in detail and the taxonomy of Liassic teleosaurs is discussed. S. brevoir is considered to be a possible synonym of S. bollensis, but S. gracilirostris can still be regarded as a separate species.

The fossils which form the subject of this note consist of part of a lower jaw, with teeth and vertebrae, imbedded in hard pyritic claystone, lent me by J. C. Mansel, Esq., and of parts of the upper and lower jaws, with several teeth in situ and loose, portions of vertebrae and of ribs, a femur, and some other bones, which, owing to their fragmentary and crushed condition, I have not been able to identify, in the British Museum. As received from Mr. Mansel, the bones in the British Museum were nearly hidden in large masses of very hard stone containing, as is usual in Kimmeridge fossils, much pyrites, which made it very diffictflt to extricate them; but this has been successfully accomplished, and the severed pieces have been very skilfully joined by Mr. Davies, to whom I am glad to take this opportunity, of expressing my obligation for much valuable assistance. Description—Upper Jaw .—Of this the British Museum has the extreme end of the snout, comprising the symphysis, with about 4 inches of both intermaxillae, forming the antero-lateral boundary of an undivided terminal nostril, which has a laterally compressed oval form, and is not swollen at the sides as in the living Gavials and in the extinct Teleosaurs. The oval nostril is indented in front by a slightly overhanging, medial, tubercular production of the symphysis. A thin seam of stone marks the open intermaxillary suture. The outer border of the upper surface of the portions of the intermaxillae bounding the

The Rev. Richard Baron, F.G.S., of the London Missionary Society, has sent to the British Museum some interesting reptilian remains from the Jurassic rocks of Madagascar, which he obtained during 1891, at Andranosamonta village, a locality situated in the north-western part of the Island. They were enclosed in a tenacious slielly limestone, so that before their examination could be proceeded with it was necessary to submit them to careful development and cleaning, a work whioh has been most ably carried out by Mr. Richard Hall, the Assistant Formatore of the Geological Department.

Vertebrate-Remains are by no means abundant in the Inferior-Oolite rocks of the Cotteswold Hills and Bath—Doulting Distriet. Mr. H. B. Woodward, F.R.S., has written—“The Inferior Oolite Series has yielded a rich and varied Invertebrate fauna, but the remains of Saurians and Fishes are very rare.“The Reptilia that have been found include Megalosaurus and Steneosaurus, and the Fishes are represented by Hybodus, Strophodus, etc.”

The author gave a short description of the Oxford Clay area in the neighbourhood of Peterborough, and mentioned the properties which caused it to be worked, in the parishes of Eye, Thorney, Whittlesey, Stanground, Fletton, and Stilton, for the manufacture of bricks and tiles. The clay is very fossiliferous at all these places, the most abundant remains being those of Belemnites Puzosianus, Gryphaea dilatata, Ammonites Elizabethœ, A. Duncani, A. convolutus, A. cordatus, A. fluctuosus, A. hecticus, A. Comptoni , and a few other species of Ammonites which Dr. Porter had not been able to determine. There were also Cerithium Damonis, Serpula vertebralis, Belemnites gracilis, Pecten , 2 sp., Nucula, Corbula, Avicula , abundant remains of Ichthyosaurus, Plesiosaurus, Pliosaurus , and Steneosaurus (?). The author had also found a portion of a spine of Ptychacanthus ornatissimus , and a few palatal teeth of Strophodus subreticulatus . What, however, he particularly called attention to in this communication was the occurrence of large quantities of fossil wood, in pieces sometimes more than a yard in length, highly bituminous, quite black, having a fracture similar to jet, and capable of almost as high a degree of polish as that mineral; it is also exceedingly brittle, and, when exposed to the air, cracks in all directions. Most of the specimens are flat, and bear on their surface impressions of Ammonites and other shells.

Originally described from the Lower Cretaceous and Jurassic rocks of England and other parts of Europe, the gigantic dinosaurs commonly known as sauropods have been subsequently discovered in great abundance in North America, while they have been recorded by myself some years ago from Southern India, and quite recently from Patagonia. We have thus evidence that the group had a very wide geographical distribution; and it is noteworthy that, while several of its North American representatives appear inseparable from their European allies, the Indian and Argentine forms are likewise referable to one and the same genus. Hitherto we have had no evidence of the occurrence of the group in Africa or Madagascar; and it is therefore a matter of considerable interest to be able to bring before the Society the fact that these gigantic dinosaurs were represented in the island last named. Before proceeding to the consideration of the specimens themselves, it is important to mention that remains of a Mesozoic reptile of a Jurassic type have already been recorded from the island, and referred to the European genus Steneosaurus . The presumption thus afforded of the occurrence of Jurassic strata in Madagascar is converted into a certainty by the discovery of a large series of molluscan remains belonging to forms characteristic of that period. The specimens that I have the opportunity of now bringing under the notice of the Society comprise a large series of reptilian bones collected by Mr. J. L. Last, at a spot about 20 miles to