Mesozoic vertebrates

Belemnites (order Belemnitida), a very successful group of
Mesozoic cephalopods, provide an important clue for understanding Mesozoic marine ecosystems and the origin of modern cephalopods. Following current hypotheses, belemnites originated in the earliest Jurassic (Hettangian, 201.6–197 Ma) with very small forms. Accord- ing to this view their paleobiogeographic distribution was restricted to northern Europe until the Pliensbachian (190–183 Ma). The fossil record is, however, biased by the fact that all the previous studies on belemnites focused on Europe. Here we report two belemnite taxa from the Hettangian of Japan: a new species of the Sinobelemnitidae and a large taxon of the suborder Belemnitina. The Sinobelemnitidae, which may be included in the future in a new suborder, have also been recorded from the Triassic of China, specimens so far poorly under- stood. The presence of a very large rostrum attributed to the Belemni- tina suggests in addition that a diverse belemnite fauna evolved earlier than previously thought. Our new findings therefore (1) extend the origin of the belemnites back by ~33 m.y. into the Triassic, (2) suggest that this group did not necessarily originate in northern Europe, and (3) imply that belemnites survived the Triassic–Jurassic extinction, one of the five big mass extinctions in the Phanerozoic. Since belem- nites provided a considerable amount of food as prey, the origination of belemnites is probably an important event also for the evolution of their predators, such as marine reptiles and sharks.

Although diplodocoid sauropods from Africa and the Americas are well known, their European record remains largely neglected. Here we redescribe Dinheirosaurus lourinhanensis from the Late Jurassic of Portugal. The holotype comprises two posterior cervical vertebrae, the dorsal series and a caudal centrum. Redescription demonstrates its validity on the basis of three autapomorphies:(1) posteriorly restricted ventral keel on posterior cervical vertebrae;(2) three small subcircular fossae posterior to the lateral coel ...

The Late Triassic Rhaetian stage is perhaps best known in southwest Britain for the bone beds of the Westbury Formation, but there are other fossil-rich horizons within this and the underlying Blue Anchor Formation. Samples from a borehole drilled at the Filton West Chord, and collected from exposures near Bristol Parkway railway station, have yielded significant fossil material from both of these formations. The assemblage recovered from the Blue Anchor Formation is similar to those from the lower Westbury Formation, yielding roughly equal proportions of chondrichthyans and osteichthyans. Assemblages recovered from the Westbury Formation are typical of those from the upper Westbury Formation, in being dominated by osteichthyans. The borehole samples have produced the first recorded evidence of crinoids in the British Triassic, and the first evidence of coleoid cephalopods, in the form of grasping hooklets, from the Rhaetian, and indeed the first from the British Triassic.

Fossil reptiles from the Mesozoic are rarities in Nordrhein-Westfalen (western Germany), and the majority of specimens found are only fragmentarily preserved. The first report of a fossil reptile, parts of a mosasaur skeleton from the Upper Cretaceous (Cenoman) of Schöppingen, was published by W. von der Marck already in 1858. Another mosasaur from Halden (Senon) was described by Pompeckj (1910). Lommerzheim (1976) reported a nearly complete wing of an unidentified pterosaur from the Upper Cretaceous (Turon) of Dinslaken. The present repository of the poorly prepared remain is unknown. The Lower Cretaceous (Berriasian) clay-pit Gerdemann near Gronau yielded plesiosaurs, dinosaurs, and turtles. Wegner (1914) erected Brancasaurus brancai, an elasmosaurid plesiosaur represented by an almost complete skeleton and mentioned a second plesiosaur genus still to be described. Recently, two probably theropodan or crocodilian vertebrae (Sachs 1996) and a humerus of a nodosaurid (Sachs 1997) were reported. The most important finds of reptiles from Nordrhein-Westfalen have been excavated in the Lower Cretaceous (Aptium) near Nehden. Among the material are numerous remains of iguanodontids including a juvenile specimen, a possible hypsilophodont, an unidentified theropod, as weil as crocodilian and turtle remains (Norman et al. 1987). Wallücke is a rich locility in the Callovium. Michaelis et al. (1997) described plesiosaurs, an ichthyosaur, a marine crocodile, and two dinosaur genera (Lexovisaurus and Dryosaurus) from this locality, however, all designation are based on rather incomplete material. A large but incomplete ichthyosaur from the Early Jurassic (Toarcian) of Bielefeld was described by Hungerbühler & Sachs (1996) as Temnodontosaurus sp. A Middle Jurassic (Bathonian) specimen also from the Bielefeld area is too incomplete for proper identification, but could represent an ophthalmosaurid ichthyosaur (Sachs & Hungerbühler 1996).

The Upper Cretaceous (Santonian) Iharku´t
terrestrial vertebrate locality in Hungary has already yielded
scincomorphan taxa such as the polyglyphanodontines
Bicuspidon and Distortodon and the chamopsiid Pelsochamops.
Besides these, more lacertilian material is
available, including a single right mandible, different from
both the abovementioned genera from Iharku´t and from
other previously known taxa. This specimen is described
here as Chromatogenys tiliquoides gen. nov. sp. nov. The
open Meckelian canal, the wide subdental shelf with deep
sulcus dentalis, and the pleurodont teeth support the
referral of the specimen to Scincomorpha. Within that,
Chromatogenys differs from groups known from Iharku´t,
such as polyglyphanodontines and chamopsiids, and is also
distinct from other contemporary scincomorphs from Europe,
North America, and Asia. It exhibits a combination of
mixed characters, some of which are shared by scincids,
cordylids, and contogeniids. Chromatogenys might be a
representative of a new family within Scincomorpha, but
its familiar relationships should be considered to be
uncertain (familia incertae sedis) until more material is
found. Chromatogenys had a durophagous dentition similar
to those of extant skinks such as Tiliqua, and most probably
had a similar diet too, composed of molluscs, eggs, insects,
small vertebrates, and fruits.

The Lufeng Formation of Yunnan Province, China has provided an important contribution to the understanding of Early Jurassic terrestrial vertebrate faunas. Here, previously described rhynchocephalian skull material is reassessed and new information is provided regarding the dentition. Unfortunately, poor preservation obscures a number of morphological features and is, in places, misleading. No significant characters can be found to warrant prior taxonomic separations. Affinity to Clevosaurus is supported by the presence of a lateral ectopterygoid-palatine contact that excludes the maxilla from the suborbital fenestra and a jugal with a long dorsal process that extends posteriorly. As in other clevosaurs, the snout is short and rounded, and all specimens demonstrate a large and steeply inclined coronoid process of the dentary. The taxon possesses a greater number of teeth than the type species Clevosaurus hudsoni and in this respect more closely resembles C. bairdi, C. convalis, or C. minor. Flanges, if at all present on the dentary teeth, are small. Differences from other described species of Clevosaurus include a palatine tooth row that is strongly curved rather than straight, and there is evidence of an additional row of teeth on the pterygoid, making three in all. Due to the lack of reliable autapomorphies the material is probably best treated as Clevosaurus sp. but further material may provide enough evidence to resurrect “Clevosaurus petilus” or the generic name “Dianosaurus.” Nevertheless, the Lufeng material represents the earliest known lepidosaur material from Asia and confirms the presence of the Rhynchocephalia in China during the Jurassic. The latter is significant because they are notably absent from productive younger localities.

The Rhaetian locality of Saint-Nicolas-de-Port (France) has yielded the most abundant and diverse mammalian assemblage known from the Late Triassic. Most of the material remains undescribed. We review here the morganucodonts from Saint- Nicolas-de-Port. We identify the upper and lower molariforms of the genus Brachyzostrodon. We also identify in the site Morganucodon peyeri, previously known from the Late Triassic of Hallau (Switzerland), as well as the genera Paceyodon and Paikasigudodon. The description of the new species Megazostrodon chenali sp. nov. extends the stratigraphical and geographical range of the genus, previously known from the Early Jurassic of southern Africa. Finally, another new morganucodont, Rosierodon anceps gen. et sp. nov., is described. The Morganucodonta is recognized as the most diverse order of Late Triassic mammals. Current fossil data suggest that Europe was the centre of initial diversification of morganucodonts at the end of the Triassic, and that morganucodonts were not much affected by the extinction event at the Triassic/Jurassic transition.

The Late Triassic Rhaetian stage is perhaps best known in southwest Britain for the bone beds of the Westbury Formation, but there are other fossil-rich horizons within this and the underlying Blue Anchor Formation. Samples from a borehole drilled at the Filton West Chord, and collected from exposures near Bristol Parkway railway station, have yielded significant fossil material from both of these formations. The assemblage recovered from the Blue Anchor Formation is similar to those from the lower Westbury Formation, yielding roughly equal proportions of chondrichthyans and osteichthyans. Assemblages recovered from the Westbury Formation are typical of those from the upper Westbury Formation, in being dominated by osteichthyans. The borehole samples have produced the first recorded evidence of crinoids in the British Triassic, and the first evidence of coleoid cephalopods, in the form of grasping hooklets, from the Rhaetian, and indeed the first from the British Triassic.

Germany has yielded a fauna of hybodontoid sharks. Isolated teeth are described as Lissodus multicuspidatu,r n. sp., Lissodus curvidens n. sp., Lissorlus noncostatu.r n. sp., Polyacrodus gramanni n. sp., and Hybodus sp.

Aus zwei nordwestdeutschen Kimmeridge-Profilen (Oberjura, Kimmeridgium) im Langenberg bei Oker (Goslar, nördliches Harzvorland) und im Einschnitt der Bundesautobahn 7 bei Uppen (östlich Hildesheim) wurde eine Fauna hybodontoider Haie geborgen. Die isolierten Zähne werden Lissodus multicuspidatus n. sp., Lissodus curvidens n. sp., Lissodus noncostatus n. sp., Polyacrodus gramanni n. sp. und Hl,bodus sp. zugeordnet.

Dinosaur remains are exceptionally scarce in northern South America and Jurassic faunas from this area are particularly poorly known. We provide descriptions of new dinosaur specimens from a bonebed in the La Quinta Formation (Early or Middle Jurassic) of western Venezuela. The specimens are disarticulated and associations of elements are rare, but at least two distinct taxa appear to be present. Ornithischian dinosaurs are identified on the basis of isolated teeth and a distal tibia. The teeth represent a non- ...

Fishes have evolved to exploit multiple ecological niches. Extant fishes in both marine (e.g., rabbitfishes, surgeonfishes) and freshwater systems (e.g., haplochromine cichlids, characiforms) have evolved specialized, scoop-like, multidenticulate teeth for benthic scraping, feeding primarily on algae. Here, I report evidence of the oldest example of specialized multidenticulate dentition in a ray-finned fish, †Hemicalypterus weiri, from the Upper Triassic Chinle Formation of southeastern Utah (∼210–205 Ma), USA. †H. weiri is a lower actinopterygian species that is phyloge- netically remote from modern fishes, and has evolved special- ized teeth that converge with those of several living teleost fishes (e.g., characiforms, cichlids, acanthurids, siganids), with a likely function of these teeth being to scrape algae off a rock substrate. This finding contradicts previously held no- tions that fishes with multicuspid, scoop-like dentition were restricted to teleosts, and indicates that ray-finned fishes were diversifying into different trophic niches and exploring differ- ent modes of feeding earlier in their history than previously thought, fundamentally altering our perceptions of the ecolog- ical roles of fishes during the Mesozoic.

Kronosaurus boyacensis is the most famous and most important Lower Cretaceous marine reptile fossil recovered from the Villa de Leyva region of Boyaca, Colombia, northern South America. To the local population it has become iconic as The Fossil (‘El Fosil’) of Colombia. Here we provide a detailed redescription of the holotype of the pliosaurid sauropterygian Kronosaurus boyacensis, and designate it a new genus, Monquirasaurus. Redescription of Monquirasaurus boyacensis required detailed consideration of the genus Kronosaurus, the Albian holotype of which is non-diagnostic at the taxonomic level of genus and species so the name Kronosaurus queenslandicus is thereby restricted to the holotype only. Aptian specimens currently assigned to Kronosaurus queenslandicus, and housed in the University Museum in Harvard, USA, are designated as the holotype and referred specimen of the new genus and species Eiectus longmani, which also provisionally includes all Albian material formerly referred to the genus Kronosaurus. The two pliosaurid marine reptiles from the Cretaceous of Colombia and Australia do not fit well into the current phylogenetic framework proposed for these gigantic marine reptiles, highlighting the importance of both northern and southern peri-Gondwanan specimens for the study of Lower Cretaceous Gap pliosaurids.

This special issue of Geological Magazine was commissioned in 2011 to commemorate Mary Anning’s first fossil marine reptile discovery and, through its scheduled release in 2014, 200 years of
continuing work following Sir Everard Home’s seminal publication. Fourteen papers by 33 international contributing authors have been included in this synopsis, and cover a broad range of topics from Mary Anning’s historical specimens to ichthyosaurian anatomy, phylogeny and ontogeny, early sauropterygian interrelationships, dyrosaurid palaeobiology, dental
histology in crocodylians and mosasaurs, and Jurassic–Cretaceous marine amniote palaeobiogeography and palaeoecology. These collective articles aim to carry on the spirit of Mary Anning’s legacy, and reflect rapidly evolving research foci that can only gain
in profile over the years to come.

Kronosaurus boyacensis is the most famous and most important Lower Cretaceous marine reptile fossil recovered from the Villa de Leyva region of Boyaca, Colombia, northern South America. To the local population it has become iconic as The Fossil (‘El Fosil’) of Colombia. Here we provide a detailed redescription of the holotype of the pliosaurid sauropterygian Kronosaurus boyacensis, and designate it a new genus, Monquirasaurus. Redescription of Monquirasaurus boyacensis required detailed consideration of the genus Kronosaurus, the Albian holotype of which is non-diagnostic at the taxonomic level of genus and species so the name Kronosaurus queenslandicus is thereby restricted to the holotype only. Aptian specimens currently assigned to Kronosaurus queenslandicus, and housed in the University Museum in Harvard, USA, are designated as the holotype and referred specimen of the new genus and species Eiectus longmani, which also provisionally includes all Albian material formerly referred to the genus Kronosaurus. The two pliosaurid marine reptiles from the Cretaceous of Colombia and Australia do not fit well into the current phylogenetic framework proposed for these gigantic marine reptiles, highlighting the importance of both northern and southern peri-Gondwanan specimens for the study of Lower Cretaceous Gap pliosaurids.

New elasmosaurid plesiosaur specimens are described from the Early Maastrichtian of Angola. Phylogenetic analyses reconstruct the Angolan taxon as an aristonectine elasmosaurid and the sister taxon of an unnamed form of similar age from New Zealand. Comparisons also indicate a close relationship with an unnamed form previously described from Patagonia. All of these specimens exhibit an ostensibly osteologically immature external morphology, but histological analysis of the Angolan material suggests an adult with paedomorphic traits. By extension, the similarity of the Angolan, New Zealand and Patagonian material indicates that these specimens represent a widespread paedomorphic yet unnamed taxon.