New remains of <Emphasis Type="Italic">Hungarosaurus tormai</Emphasis> (Ankylosauria,Dinosauria) from the Upper Cretaceous of Hungary: skeletal reconstruction and body mass estimation

Hungarosaurus tormai is a medium-sized nodosaurid ankylosaur that was described on the basis of four partial skeletons from the Santonian (Upper Cretaceous) of Hungary. In this paper, a new fifth skeleton and several isolated remains are described which greatly improve our knowledge of this primitive nodosaurid ankylosaur. Isolated cranial remains referred to juvenile individuals provide new information on the development of cranial ornamentation in nodosaurid ankylosaurs. Apart from both preserved mandibles with in situ dentition, the fifth partial skeleton contains several previously unknown limb elements (humerus, ulnae, radius) that indicate unusual limb proportions for Hungarosaurus compared with other ankylosaurs. On the basis of the five partial skeletons and the isolated remains, a skeletal and dermal armor reconstruction is attempted. Body mass calculations using three different methods yield an estimate of 650 kg for H. tormai.      

Partial skeleton of Dracopelta zbyszewskii N. Gen. And N. SP., an ankylosaurian dinosaur from the Upper Jurassic of Portugal

The holotype of the nodosaurid ankylosaur Dracopelta zbyszewskii n. gen. and n. sp. is described from the Kimmeridgian(Upper Jurassic) of Ribomar on the west coast of Portugal. This is the first Upper Jurassic ankylosaur to be described that is represented by articulated bones. The specimen consists of a partial rib cage with thirteen dorsal vertebrae and five different types of dermal armor, two of wich show a partial overlap between adjacent plates.     

A new crocodylian from the late Maastrichtian of Spain: implications for the initial radiation of crocodyloids

Background

The earliest crocodylians are known primarily from the Late Cretaceous of North America and Europe. The representatives of Gavialoidea and Alligatoroidea are known in the Late Cretaceous of both continents, yet the biogeographic origins of Crocodyloidea are poorly understood. Up to now, only one representative of this clade has been known from the Late Cretaceous, the basal crocodyloid Prodiplocynodon from the Maastrichtian of North America.

Methodology/Principal Findings

The fossil studied is a skull collected from sandstones in the lower part of the Tremp Formation, in Chron C30n, dated at −67.6 to 65.5 Ma (late Maastrichtian), in Arén (Huesca, Spain). It is located in a continuous section that contains the K/P boundary, in which the dinosaur faunas closest to the K/P boundary in Europe have been described, including Arenysaurus ardevoli and Blasisaurus canudoi. Phylogenetic analysis places the new taxon, Arenysuchus gascabadiolorum, at the base of Crocodyloidea.

Conclusions/Significance

The new taxon is the oldest crocodyloid representative in Eurasia. Crocodyloidea had previously only been known from the Palaeogene onwards in this part of Laurasia. Phylogenetically, Arenysuchus gascabadiolorum is situated at the base of the first radiation of crocodyloids that occurred in the late Maastrichtian, shedding light on this part of the cladogram. The presence of basal crocodyloids at the end of the Cretaceous both in North America and Europe provides new evidence of the faunal exchange via the Thulean Land Bridge during the Maastrichtian.     

Armored dinosaurs(Ornithischia: Ankylosauria)) from the Middle and Upper Jurassic of England

Hitherto the earliest positive record of ankylosaurs(armored dinosaurs) has been from beds well up in the Lower Cretaceous; in fact, however, specimens referable to the ankylosaurian family Nodosauridae are present in the Middle and Upper Jurassic of England: from the Middle Callovian [partial mandible Sarcolestes leedsiLydekker]], the Upper Oxfordian [femur Cryptodraco eumerus (Seeley)), maxilla Priodontognathus phillipsii (Seeley))], and the Upper Tithonian [caudal vertebra, tooth]. The Tithonian tooth and those of Priodontognathus are large and similar to those of the nodosaurids Priconodon and Sauropelta (Lower Cretaceous, U.S.A.). The incomplete mandible of Sarcolestes is similar to that of Sauropelta with a dermal scute fused to the lateral surface, and a tooth row extending to the anterior end of the jaw; an unusual feature is the caniniform first tooth. The quadrupedal ankylosaurs and stegosaurs probably represent separate evolutionary lines that extend back at least into the Lower Jurassic, and both lines probably evolved from ornithopod dinosaurs that were bipedal. Nodosaurid ankylosaurs occur in Europe from the Middle Jurassic to Late Cretaceous and probably reached North America via a filter route in the early Cretaceous.     

New ankylosaurian material from the Upper Cretaceous of Transylvania

Ankylosaurian remains from the Transylvanian Basin, Romania, are extremely rare. More than 100 years after the discovery of the first and only better-known assemblage, namely the type material of Struthiosaurus transylvanicus, new ankylosaurian material has been discovered in the Maastrichtian of the Ha?eg Basin, as well as at another locality (Vurp?r), in the Transylvanian Basin, that is described here. The material consists of one tooth in a small jaw fragment (from the Ha?eg Basin) and at least two accummulations of associated, as well as several isolated, postcranial elements (from Vurp?r). No diagnostic elements are preserved that would overlap with the type of S. transylvanicus, so we cannot assign any of the new specimens to this species. The tooth shows marked differences compared to those of other anklyosaurs including S. austriacus and Hungarosaurus in having only six, more or less equally sized, apically pointed cusps separated by deep grooves. The postcranial material from Vurp?r represents at least three different individuals. The humerus is the most diagnostic element among the postcranial remains being most similar both in size and morphology to humeri referred to as Struthiosaurus from different European localities, thus here we refer the humerus and probably associated elements preserved in one assemblage to as cf. Struthiosaurus sp.; the remaining specimens from Vurp?r are retained as Nodosauridae indet. Histological studies have confirmed the adult nature of all sampled bones in the Vurp?r ankylosaur material suggesting that these fully grown animals were of similar size to Struthiosaurus, a small-bodied nodosaurid the ontogenetic status of which, however, has never been investigated histologically. The obviously diminished body size of the Transylvanian ankylosaurs compared to other members of the clade could be explained by insular dwarfism using the same histology-based argument as presented for Magyarosaurus.     

A new abelisaurid dinosaur from the Late Cretaceous of southern France: Palaeobiogeographical implications

The Abelisauridae are a family of mainly Cretaceous theropod dinosaurs with a wide distribution across the Gondwanan land masses. Although their presence in Europe was reported twenty-five years ago, it has often been considered as controversial largely because of the incompleteness of the available specimens. We report here the discovery of well-preserved abelisaurid material, including a highly diagnostic braincase, at a Late Cretaceous (late Campanian) locality in the Aix-en-Provence Basin, near the eponym city in south-eastern France. A new abelisaurid taxon is erected, Arcovenator escotae gen. nov., sp. nov., on the basis of cranial and postcranial material. A phylogenetic analysis reveals that the new Abelisauridae from Provence is more closely related to taxa from India and Madagascar than to South American forms. Moreover, Genusaurus, Tarascosaurus and the previous Late Cretaceous discoveries are identified as basal abelisaurids. Contrary to previously proposed palaeobiogeographical models of abelisaurid evolution, the presence of the new taxon in Europe suggests that Europe and Africa may have played a major role in abelisaurid dispersal, which apparently involved crossing marine barriers.     

Lower limits of ornithischian dinosaur body size inferred from a new Upper Jurassic heterodontosaurid from North America

The extremes of dinosaur body size have long fascinated scientists. The smallest (<1 m length) known dinosaurs are carnivorous saurischian theropods, and similarly diminutive herbivorous or omnivorous ornithischians (the other major group of dinosaurs) are unknown. We report a new ornithischian dinosaur, Fruitadens haagarorum, from the Late Jurassic of western North America that rivals the smallest theropods in size. The largest specimens of Fruitadens represent young adults in their fifth year of development and are estimated at just 65–75 cm in total body length and 0.5–0.75 kg body mass. They are thus the smallest known ornithischians. Fruitadens is a late-surviving member of the basal dinosaur clade Heterodontosauridae, and is the first member of this clade to be described from North America. The craniodental anatomy and diminutive body size of Fruitadens suggest that this taxon was an ecological generalist with an omnivorous diet, thus providing new insights into morphological and palaeoecological diversity within Dinosauria. Late-surviving (Late Jurassic and Early Cretaceous) heterodontosaurids are smaller and less ecologically specialized than Early (Late Triassic and Early Jurassic) heterodontosaurids, and this ecological generalization may account in part for the remarkable 100-million-year-long longevity of the clade.     

New material of Xyelydidae (Hymenoptera) from the Lower Cretaceous Yixian Formation of China

Chifengilyda robusta, a new extinct sawfly genus and new species assigned to Xyelidae, is described and figured here based on one fossil specimen from the Lower Cretaceous Yixian Formation of Ningcheng in Inner Mongolia, China. Chifengilyda robusta n. gen. n. sp. differs from other xyelydids in having a forewing with pterostigma completely sclerotized, Sc closer to C, Sc1 about 3 times as long as Sc2, Sc1 intersecting C far beyond Rs base, 2r-m postfurcal and cell 1mcu relatively large. This new taxon further enriches the diversity of Xyelydidae in the Early Cretaceous, and even enhances our understanding of the evolution and inter-genera and interspecies relationships of this family.     

A New Small-Bodied Azhdarchoid Pterosaur from the Lower Cretaceous of England and Its Implications for Pterosaur Anatomy,Diversity and Phylogeny

Background

Pterosaurs have been known from the Cretaceous sediments of the Isle of Wight (southern England, United Kingdom) since 1870. We describe the three-dimensional pelvic girdle and associated vertebrae of a small near-adult pterodactyloid from the Atherfield Clay Formation (lower Aptian, Lower Cretaceous). Despite acknowledged variation in the pterosaur pelvis, previous studies have not adequately sampled or incorporated pelvic characters into phylogenetic analyses.

Methodology/Principal Findings

The new specimen represents the new taxon Vectidraco daisymorrisae gen. et sp. nov., diagnosed by the presence of a concavity posterodorsal to the acetabulum and the form of its postacetabular process on the ilium. Several characters suggest that Vectidraco belongs to Azhdarchoidea. We constructed a pelvis-only phylogenetic analysis to test whether the pterosaur pelvis carries a useful phylogenetic signal. Resolution in recovered trees was poor, but they approximately matched trees recovered from analyses of total evidence. We also added Vectidraco and our pelvic characters to an existing total-evidence matrix for pterosaurs. Both analyses recovered Vectidraco within Azhdarchoidea.

Conclusions/Significance

The Lower Cretaceous strata of western Europe have yielded members of several pterosaur lineages, but Aptian pterosaurs from western Europe are rare. With a pelvis length of 40 mm, the new animal would have had a total length of c. 350 mm, and a wingspan of c. 750 mm. Barremian and Aptian pterodactyloids from western Europe show that small-bodied azhdarchoids lived alongside ornithocheirids and istiodactylids. This assemblage is similar in terms of which lineages are represented to the coeval beds of Liaoning, China; however, the number of species and specimens present at Liaoning is much higher. While the general phylogenetic composition of western European and Chinese communities appear to have been approximately similar, the differences may be due to different palaeoenvironmental and depositional settings. The western Europe pterodactyloid record may therefore be artificially low in diversity due to preservational factors.     

A new genus of Bothremydidae (Chelonii,Pleurodira) in the Cretaceous of Southwestern Europe

Although the Bothremydidae are the most abundant and diverse group of turtles in the Upper Cretaceous fauna of Europe, the record attributed to the genus Elochelys was, until now, quite scarce. However, the revision of the specimens previously attributed to this taxon and the analysis of new material from the Spanish record significantly increase our knowledge of these turtles. Evaluation of the morphological variability, affecting many characters that have been considered diagnostic until now and comparisons with other members of the node Bothremydini, allow us to amend the diagnosis of the genus Elochelys, recognising Elochelys perfecta as a valid single species and reassigning its other representative, “Elochelys” convenarum, to the new genus Iberoccitanemys.     

Some rare helical Ammonoidea from the lower Aptian (Lower Cretaceous) of the Paris Basin (NE France)

In the present paper, we describe and figure some rare lower Aptian (Lower Cretaceous) helical ammonoids from the Deshayesites deshayesi Zone of the Argiles à Plicatules Formation (Paris Basin, NE France). Those are the only helical ammonoids known in this zone so far. They were only occasionally evoked in literature and this is probably on the basis of the specimens here described that, according to us, the genus Toxoceratoides (Helicancylidae) was wrongly regarded as possessing an early helical spiral part. We demonstrate here that these specimens are not belonging to Toxoceratoides nor Helicancylidae: they are interpreted as ‘abnormally’ helical representatives of the genus Ancyloceras (Ancyloceratidae) or a new taxon of Ancyloceratidae.     

Ankylosaur Remains from the Early Cretaceous (Valanginian) of Northwestern Germany

A fragmentary cervico-pectoral lateral spine and partial humerus of an ankylosaur from the Early Cretaceous (early Valanginian) of Gronau in Westfalen, northwestern Germany, are described. The spine shows closest morphological similarities to the characteristic cervical and pectoral spines of Hylaeosaurus armatus from the late Valanginian of England. An extensive comparison of distal humeri among thyreophoran dinosaurs supports systematic differences in the morphology of the distal condyli between Ankylosauria and Stegosauria and a referral of the Gronau specimen to the former. The humerus fragment indicates a rather small individual, probably in the size range of H. armatus, and both specimens are determined herein as ?Hylaeosaurus sp.. A short overview of other purported ankylosaur material from the Berriasian-Valanginian of northwest Germany shows that, aside from the material described herein, only tracks can be attributed to this clade with confidence at present.     

Unusual deinonychosaurian track morphology (Velociraptorichnus zhangi n. ichnosp.) from the Lower Cretaceous Xiaoba Formation,Sichuan Province,China

A new Lower Cretaceous dinosaur footprint locality named the Mujiaowu tracksite in the Xiaoba Formation, Sichuan Province, has yielded a new assemblage containing the didactyl deinonychosaurian ichnogenus Velociraptorichnus. This is the eleventh report in the global record, the seventh from Asia and the fifth from China. All, except for an isolated report from Europe, occur in Lower Cretaceous deposits. Unlike previous reports of the ichnogenus, the Mujiaowu site has yielded both didactyl Velociraptorichnus tracks and tridactyl tracks which we interpret as a different expression of this same ichnogenus, caused by registration of digit II, either due to special substrate conditions or to less claw retraction. These tridactyl Velociraptorichnus footprints are assigned to the new ichnospecies Velociraptorichnus zhangi. Such tridactyl deinonychosaurid footprint morphology is predictable, but based on current ichnological evidence appears to be the exception rather than the rule.     

Necrosaurus or Palaeovaranus? Appropriate nomenclature and taxonomic content of an enigmatic fossil lizard clade (Squamata)

Necrosaurus cayluxi is an enigmatic lizard from the Paleogene of the Phosphorites of Quercy, France that was first mentioned in the 19th century. Although it is generally believed that Filhol was the author who established this taxon, I am herein demonstrating that authorship should in fact be attributed to Zittel, a fact that also influences not only its generic nomenclature, but also its appropriate type material. As such, the valid name for this taxon should be Palaeovaranus cayluxi and its holotype is a left maxilla. Additionally, Ophisauriscus eucarinatus from the middle Eocene of Geiseltal, Germany, another taxon that was previously assigned to Necrosaurus, is herein shown to be a nomen dubium, whereas Melanosauroides giganteus from the same locality, is considered a valid species and is recombined as Palaeovaranus giganteus comb. nov. The suggested changes in nomenclature also affect “Necrosauridae”, a poorly defined clade of lizards from the Cretaceous–Paleogene of Europe, North America, and Asia. In order to maintain nomenclatural stability and define a monophyletic lineage, I am here establishing the new family Palaeovaranidae fam. nov., which includes solely the genus Palaeovaranus. The known occurrences of Palaeovaranus across the Paleogene of Western Europe are discussed.     

A Ceratopsian Dinosaur from the Lower Cretaceous of Western North America,and the Biogeography of Neoceratopsia

The fossil record for neoceratopsian (horned) dinosaurs in the Lower Cretaceous of North America primarily comprises isolated teeth and postcrania of limited taxonomic resolution, hampering previous efforts to reconstruct the early evolution of this group in North America. An associated cranium and lower jaw from the Cloverly Formation (?middle–late Albian, between 104 and 109 million years old) of southern Montana is designated as the holotype for Aquilops americanus gen. et sp. nov. Aquilops americanus is distinguished by several autapomorphies, including a strongly hooked rostral bone with a midline boss and an elongate and sharply pointed antorbital fossa. The skull in the only known specimen is comparatively small, measuring 84 mm between the tips of the rostral and jugal. The taxon is interpreted as a basal neoceratopsian closely related to Early Cretaceous Asian taxa, such as Liaoceratops and Auroraceratops. Biogeographically, A. americanus probably originated via a dispersal from Asia into North America; the exact route of this dispersal is ambiguous, although a Beringian rather than European route seems more likely in light of the absence of ceratopsians in the Early Cretaceous of Europe. Other amniote clades show similar biogeographic patterns, supporting an intercontinental migratory event between Asia and North America during the late Early Cretaceous. The temporal and geographic distribution of Upper Cretaceous neoceratopsians (leptoceratopsids and ceratopsoids) suggests at least intermittent connections between North America and Asia through the early Late Cretaceous, likely followed by an interval of isolation and finally reconnection during the latest Cretaceous.     

Pelvis of Gargoyleosaurus (Dinosauria: Ankylosauria) and the Origin and Evolution of the Ankylosaur Pelvis

Discovery of a pelvis attributed to the Late Jurassic armor-plated dinosaur Gargoyleosaurus sheds new light on the origin of the peculiar non-vertical, broad, flaring pelvis of ankylosaurs. It further substantiates separation of the two ankylosaurs from the Morrison Formation of the western United States, Gargoyleosaurus and Mymoorapelta. Although horizontally oriented and lacking the medial curve of the preacetabular process seen in Mymoorapelta, the new ilium shows little of the lateral flaring seen in the pelvis of Cretaceous ankylosaurs. Comparison with the basal thyreophoran Scelidosaurus demonstrates that the ilium in ankylosaurs did not develop entirely by lateral rotation as is commonly believed. Rather, the preacetabular process rotated medially and ventrally and the postacetabular process rotated in opposition, i.e., lateral and ventrally. Thus, the dorsal surfaces of the preacetabular and postacetabular processes are not homologous. In contrast, a series of juvenile Stegosaurus ilia show that the postacetabular process rotated dorsally ontogenetically. Thus, the pelvis of the two major types of Thyreophora most likely developed independently. Examination of other ornithischians show that a non-vertical ilium had developed independently in several different lineages, including ceratopsids, pachycephalosaurs, and iguanodonts. Therefore, a separate origin for the non-vertical ilium in stegosaurs and ankylosaurs does have precedent.     

Hadodiaptomus dumonti n. gen., n. sp., a new freshwater stygobitic calanoid (Crustacea: Copepoda: Calanoida) from Vietnam (South Asia) and a new member of the subfamily Speodiaptominae Borutzky, 1962

A new species of freshwater stygobitic calanoid, Hadodiaptomus dumonti n. gen., n. sp., from a cave in Vietnam (South Asia) is described. It is the ninth taxon from the order Calanoida described from freshwater subterranean (i.e. cave) environments. It is the fourth member of the subfamily Speodiaptominae Borutzky, 1962. It differs from stygobitic taxa in Europe and Mexico by numerous characters, especially in the armature of P1–P5, antenullas, mouth parts and genital segments in both sexes. Arthrodial membrane development from CII to CV is different from epigean as well as from subterranean taxa. These differences suffice to raise a new genus–Hadodiaptomus, characterised by two-segmented exopodites and endopodites of P1–P4 and reduced P5 endopodites in both sexes. Males are without widened segments 13–18 on right A1. Relations with other stygobitic taxa of the subfamily Speodiaptominae are discussed.     

New mites Terraphagus antipodus gen. n., sp. n. and Neohyadesia minor sp. n. (Acarina: Astigmata: Algophagidae) from islands of the Southern Ocean

Mites are a diverse and important component in the soils of the Southern Ocean islands, but for many groups, their taxonomy and biogeography is little studied. This paper reports the Algophagidae, a poorly known family, from the New Zealand region for the first time. The study used soil samples from seabird burrows, brackish algal wrack samples and a museum collection to recover specimens. Terraphagus antipodus gen. n., sp. n. is described from grey petrel Procellaria cinerea burrow soil on the Antipodes Islands, New Zealand. The axillary organ is confined to the dorsum; the epigynal apodeme ends are fused with the ends of coxal apodeme II; seta 2a and ω2 are absent, and the famulus is bilobed. Males have the sternum fused to coxal apodemes II; the tarsal setae of legs I, III and IV of the male are modified for mate guarding. The short stout legs I and II end in huge spines in females as e, d, q, s, wa and hT. From brackish algal wrack, Lake Forsyth/Wairewa, Canterbury, New Zealand, another algophagid Neohyadesia minor sp. n. is described and illustrated. The new species is the smallest known algophagid. A neohyadesid collected in 1961 is newly reported here from Eudyptes sp. penguin rookery mud from North Head, Macquarie Island. These records further extend the known microhabitats of the family to the allochthonous marine seabird nutrient flow into islands in the New Zealand region and make Neohyadesia Hughes and Goodman, 1969 present in all Southern Ocean provinces.     

A New Large-Bodied Oviraptorosaurian Theropod Dinosaur from the Latest Cretaceous of Western North America

The oviraptorosaurian theropod dinosaur clade Caenagnathidae has long been enigmatic due to the incomplete nature of nearly all described fossils. Here we describe Anzu wyliei gen. et sp. nov., a new taxon of large-bodied caenagnathid based primarily on three well-preserved partial skeletons. The specimens were recovered from the uppermost Cretaceous (upper Maastrichtian) Hell Creek Formation of North and South Dakota, and are therefore among the stratigraphically youngest known oviraptorosaurian remains. Collectively, the fossils include elements from most regions of the skeleton, providing a wealth of information on the osteology and evolutionary relationships of Caenagnathidae. Phylogenetic analysis reaffirms caenagnathid monophyly, and indicates that Anzu is most closely related to Caenagnathus collinsi, a taxon that is definitively known only from a mandible from the Campanian Dinosaur Park Formation of Alberta. The problematic oviraptorosaurs Microvenator and Gigantoraptor are recovered as basal caenagnathids, as has previously been suggested. Anzu and other caenagnathids may have favored well-watered floodplain settings over channel margins, and were probably ecological generalists that fed upon vegetation, small animals, and perhaps eggs.