A tiny lizard (Lepidosauria,Squamata) from the Lower Cretaceous of Spain

Abstract: The smallest living amniotes are all lizards, but the fossil history of this size trait in Squamata is difficult to follow because small skeletons have low preservation potential and are often hard to detect in the field. A new squamate taxon, Jucaraseps grandipes gen. et sp. nov., is here described on the basis of an articulated skeleton from the Early Cretaceous Spanish lagerstätten of Las Hoyas. It differs from other known Mesozoic lizards in combining very small body size with a short rostrum, low maxillary tooth count, a relatively slender and elongated body, and short limbs with large hind feet. Phylogenetic analysis using TNT places it on the stem of a clade encompassing scincomorphs, gekkotans, snakes, amphisbaenians and anguimorphs. Comparison with modern lizards suggests it was probably a cryptic surface or subsurface ground dweller but not a burrower.     

Middle Jurassic trace fossils from the Ridang Formation in Sajia County,South Tibet,and their palaeoenvironmental significance

An ichnofauna consisting of 18 ichnospecies (one of them new) in 14 ichnogenera are described for the first time from the Middle Jurassic Ridang Formation in Sajia County, South Tibet. The ichnofauna can be subdivided into two ichnoassemblages in ascending stratigraphic order: the Palaeophycus–Megagrapton ichnoassemblage in the lower and middle parts of the Ridang Formation, followed by the Cosmorhaphe–Nereites–Paleodictyon ichnoassemblage in the upper Ridang Formation. Overall, the trace fossils occur in a middle–distal turbidite fan sequence, as evidenced by both sedimentological analysis and the composition of the trace fossils. Several subenvironments of the middle–distal fan system have been recognized on the basis of the spatial distribution of the trace fossils. Typically, the channel-fill deposits in the middle part of the turbidite fan lack trace fossils, the interchannel and upper channel-fill (levee) subenvironments of the middle turbidite fan contain abundant facies-crossing trace fossils, in contrast to the distal part of the turbidite fan where deep-water trace fossils are dominant. The ichnofauna is similar to typical flysch ichnofaunas from Europe and North America in characteristics, and is interpreted to represent a typical deep-sea Nereites ichnofacies. The presence of these deep-sea trace fossils therefore would suggest that a continental slope environment existed in southern Tibet during the Middle Jurassic and the study area was located in a slope-abyssal plain setting.     

Trace and soft body fossils from the Pedroche Formation (Ovetian, Lower Cambrian of the Sierra de Córdoba, S Spain) and their relation to the Pedroche event

The low Lower Cambrian rocks from the Sierra de Córdoba contain one of the best successions in Europe, which consists of well exposed mixed facies with abundant fossil assemblages showing long stratigraphical ranges throughout the Pedroche Formation. These assemblages include diverse Ovetian archaeocyaths, trilobites, small shelly fossils, calcimicrobes, trace fossils and stromatolites. Trace fossils are still poorly known, and thus they are the main objective of this work. Ichnological data are obtained from the Arroyo de Pedroche 1, Arroyo de Pedroche 2 and Puente de Hierro sections. Trace fossils include the ichnogenera Bergaueria, aff. Bilinichnus, Cochlichnus, aff. Cosmorhaphe?, Cylindrichnus, Dactyloidites, Dimorphichnus, Diplichnites, Monocraterion, Palaeophycus, aff. Phycodes, Planolites, Psammichnites, Rusophycus, Skolithos, Torrowangea and Treptichnus, as well as faecal pellets, meniscate trace fossils and others. They are abundant in shales and sandstones, and indicate important changes in the benthic conditions with respect to the underlying Torreárboles Formation. Changes in fossil assemblages within Member I of the Pedroche Formation indicate palaeoecological disruptions, which led to the disappearance of numerous archaeocyath species and the decrease of stromatolite biodiversity. This was followed by dominance of trilobite and brachiopod assemblages, accompanied by trace fossils of the Psammichnites ichnosp. A ichnoassociation. This biotic turnover (Pedroche event) occurred at the lower part of the archaeocyath Zone III, within the Bigotina bivallata biozone. The diagnoses of the ichnospecies Cochlichnus anguineus and Dactyloidites cabanasi are emended.     

The infaunal echinoid Micraster: Taphonomic pathways indicated by sclerozoan trace and body fossils from the Upper Cretaceous of northern Spain

Micraster echinoid fossils are common in the Upper Cretaceous Olazagutía Formation of northern Spain. Tests frequently record sclerobiont signatures (including bioerosion and encrustation), left by reaction and/or coaction phenomena. Among bioerosion structures, Oichnus simplex, O. paraboloides, O. ichnosp. A, Trypanites solitarius, Rogerella ichnosp. indet., Centrichnus cf. eccentricus, Maeandropolydora ichnosp. indet. and fungal microborings are found, as well as pits and fractures. As for sclerozoan body fossils, bivalves (Dimyidae, Anomiidae, Plicatulidae and other Pectinacea), polychaete annelids (serpulids and spirorbids), lituolid foraminiferans (Haddoniidae and Coscinophragmatidae) and bryozoans (cheilostomate ones and others undetermined), as well as other less common groups, have been identified. Taphonomic paths followed by Micraster tests are analysed, based on conservation state and degree of colonisation and sedimentary filling. This allows to distinguish between accumulated fossils and non accumulated ones (including resedimented and reelaborated ones).     

Oldest known avian footprints from Australia: Eumeralla Formation (Albian), Dinosaur Cove,Victoria

Two thin‐toed tridactyl tracks in a fluvial sandstone bed of the Eumeralla Formation (Albian) at Dinosaur Cove (Victoria, Australia) were likely made by avian trackmakers, making these the oldest known fossil bird tracks in Australia and the only Early Cretaceous ones from Gondwana. These tracks, which co‐occur on the same surface with a slightly larger nonavian theropod track, are distinguishable by their anisodactyl form, hallux impressions and wide digit II–IV divarication angles. A lengthy hallux impression and other deformational structures associated with one track indicate foot movement consistent with an abrupt stop, suggesting its tracemaker landed after either flight or a hop. The single nonavian theropod track is similar to other tracks described from the Eumeralla Formation at another locality. The avian footprints are larger than most Early Cretaceous avian tracks recorded worldwide, indicating sizeable enantiornithine or ornithurine species in formerly polar environments of Australia. The avian tracks further supplement scant body fossil evidence of Early Cretaceous birds in southern Australia, which includes a furcula from the Wonthaggi Formation. Because of this discovery, Dinosaur Cove, previously known for its vertebrate body fossils, is added to a growing list of Early Cretaceous vertebrate tracksites in southern Australia.     

Hoof-Like Unguals,Skin, and Foot Movements Deduced from Deltapodus Casts of the Galve Basin (Upper Jurassic-Lower Cretaceous,Teruel, Spain)

Galve (Teruel, Spain) is a town in the interior of a synclinal fold with Upper Jurassic marine limestones along its flanks, and, in its core, Upper Jurassic–Lower Cretaceous continental and shoreline sediments crop out. The core sediments cover an area about 8 km², and contain a concentration of sites with footprints, bones, and eggshells of dinosaurs. The footprints are both shafts and natural casts. Some casts are attributed to stegosaurs (Deltapodus). The Deltapodus casts are characterized by features that allow us to make direct observations on the skin formed by polygonal scales, and ellipsoidal “hooves,” as well as deductions on the movement of the limbs during walking. According to the opinion of some authors, dinosaur footprints are indicators of the motion of their limbs and sometimes of the whole body. So far, results have been deduced from theropod, ornithopod, and sauropod footprints. This article shows the results obtained from analis of the aforementioned Deltapodus casts, i.e., forelimb movement similar to that of the forelimbs of sauropods, and the rigid structure of the autopodial part of the hind limb.     

Lower Ovetian (Lower Cambrian) trilobites and biostratigraphy of the Pedroche Formation (Sierra de Córdoba, southern Spain)

The low Lower Cambrian rocks from the Sierra de Córdoba, which consist of well exposed mixed facies and abundant fossil assemblages showing long stratigraphic ranges throughout the Pedroche Formation, represent one of the best successions of this age in Europe. The fossil assemblages include diverse Ovetian archaeocyaths, trilobites, small shelly fossils, calcimicrobia, trace fossils and stromatolites. Trilobites are still poorly known, and thus they are the main objective of this work. The trilobites studied originate from three sections. At the Arroyo de Pedroche 1 section, cf. Bigotinella and Bigotinabivallata are replaced towards the top by Lemdadellalinaresae, Lemdadellaperejoni sp. nov. and, finally, by Eoredlichia cf. ovetensis. At the Arroyo de Pedroche 2 section, Lemdadellalinaresae is replaced by Lemdadellaperejoni sp. nov. and Eoredlichia cf. ovetensis, while at the Puente de Hierro section Lemdadellalinaresae, L. aff. linaresae and Serraniaverae occur together. These new biostratigraphic data confirm that the Pedroche Formation, originally defined as a repetitive sequence of four members, contains only two members. The new trilobite discoveries permit the first tentative correlation between the Ovetian of southern Spain and Lower Cambrian strata from the High Atlas (Morocco), Siberia, Antarctica and Carteret (France).     

Basal titanosauriform (Dinosauria, Sauropoda) teeth from the Lower Cretaceous Yixian Formation of Liaoning Province, China

The Yixian Formation of Liaoning Province, People's Republic of China has yielded a diverse fauna of non-avian dinosaurs, but is dominated by small-bodied taxa. Here, we describe a series of isolated teeth from the Lujiatun Beds of the formation that are referable to a basal titanosauriform sauropod. Some of the teeth possess a distinctive circular boss on the lingual surface, which suggests that they are referable to cf. Euhelopus sp. This identification provides some additional support for biostratigraphical correlations between the Jehol Group and the Mengyin Formation of Shandong Province that suggest an Early Cretaceous age for the latter unit. Moreover, the titanosauriform affinities of the teeth provide further evidence for the dominance of this sauropod clade in eastern Asia during the Cretaceous.     

Decapod Crustacea from the Agrio Formation (Lower Cretaceous) of the Neuquén Basin,Argentina

Abstract: Two species of decapod crustacean are recorded from the Agua de la Mula Member of the Agrio Formation (Upper Hauterivian – Lower Barremian) of the Neuquén Basin of west‐central Argentina, namely Astacodes falcifer Bell and a new species of Palaeohomarus, P. pacificus. The preservation of the specimens is exceptional, some showing delicate compound eyes and a stridulatory apparatus, features rarely found in fossil forms. Many specimens are preserved articulated inside calcareous nodules, within dark‐grey shales. The lobster‐bearing sediments accumulated in a low‐energy marine environment and diagenetic mineralization occurred very rapidly, prior to significant decay, thus allowing exceptional preservation of specimens. Palaeohomarus was a rare genus in the Cretaceous with a palaeogeographic distribution restricted to the Mediterranean Tethys, the eastern USA and Madagascar, while Astacodes falcifer has been recorded only from Speeton (eastern England) and Neuquén.     

Ephedroid fossil pollen from the Lower Cretaceous (Upper Albian) of Hokkaido,Japan

This paper presents eight ephedroid palynomorphs from the Lower Cretaceous (Upper Albian) of Hokkaido, Japan. The ephedroid palynomorphs are ellipsoid and polyplicate pollen grains that show a wide range of variation in pollen size, shape, and plication. These ephedroid palynomorphs suggest a wide range of diversity in Gnetales at mid- or high-paleolatitude in the eastern side of Lauresia during the Upper Albian.     

New Trigonioidoidea (Bivalvia; Unionoida) from the Early Cretaceous of Spain

Abstract: Two taxa belonging to the Trigonioidoidea (Order Unionoida) are described from the Early Cretaceous of Spain. Nippononaia (Paranippononaia) camerana subgen. et sp. nov. is described from the Aptian of the Cameros Basin of the north‐west Iberian Range. Subnippononaia fordi Barker et al., 1997 is described from new material from the Calizas de la Huérguina Formation (Late Barremian) from Las Hoyas and Buenache de la Sierra, Cuenca Province, and Subnippononaia is raised to generic status. The stratigraphy and palaeoenvironment of the Cornago G exposure of the Enciso Group where Nippononaia (Paranippononaia) camerana originates is interpreted as a fresh to brackish water system.     

Los Cayos Dinosaur Tracksite: An Overview on the Lower Cretaceous Ichno-Diversity of the Cameros Basin (Cornago,La Rioja Province,Spain)

The Los Cayos dinosaur tracksite is located at the eastern sector of the Cameros Basin (Cornago Township, La Rioja province), NE Spain. The sediments consist of interbedded terrigenous siliciclastics and carbonates belonging to the Enciso Group (Early Cretaceous, Aptian in age). The sedimentological and faunal evidence suggests that these sediments were deposited in a low gradient lacustrine environment. Los Cayos constitutes a relatively wide area with at least 6 localities that have yielded dinosaur tracks. More than 2,000 dinosaur tracks have been discovered to date. Medium to large theropod dinosaurs constitute about 95% of the ichnofauna. Ornithopod dinosaur tracks have been reported from only one of the outcrops (Los Cayos D). Los Cayos S has yielded theropod and sauropod tracks. One sauropod trackway shows a narrow-gauge locomotion pattern and a manus print morphology suggesting that the trackmaker was a titanosaurid, or at least a titanosauriform sauropod. Some pterosaur manus impressions, avian-like footprints of small size and possible turtle tracks complete the assemblage of one of the most impressive and best-preserved dinosaur tracksites of the European Lower Cretaceous.     

Neoselachians (Chondrichthyes,Elasmobranchii) from the Lower and lower Upper Cretaceous of north‐eastern Spain

Extensive sampling of several Barremian and Albian–Cenomanian levels across the Aguilón, Oliete and Aliaga subbasins of the Iberian Basin, north‐east Spain, yielded abundant material of new or so far poorly known neoselachians. The faunas consist of 16 different species, five of which represent new species and two new genera: Cantioscyllium brachyplicatum sp. nov. , Platypterix venustulus gen. et sp. nov. , Ptychotrygon pustulata sp. nov. , Ptychotrygon striata sp. nov. and Iberotrygon plagiolophus gen. et sp. nov. In addition, teeth of Heterodontus cf. H. carerens, Lamniformes indet., Pteroscyllium sp., Scyliorhinidae indet., Rhinobatos sp., Spathobatis sp., Belemnobatis sp., Ptychotrygon geyeri, Ptychotrygon sp. and Celtipristis herreroi are described. The new family Ptychotrygonidae is defined. The localities comprise palaeoenvironments ranging from lacustrine and shallow lake to open marine settings. Neoselachians are almost completely absent from continental settings in the Barremian, as a result of prevailing freshwater conditions, but became more abundant in marine strata. The Albian–Cenomanian selachian assemblage is the most profuse and diverse of the three assemblages studied. It is dominated by small, benthic and near‐coastal taxa, for instance Cantioscyllium and Ptychotrygon, and contains several new species, including an endemic batoid, Iberotrygon plagiolophus gen. et sp. nov. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 155 , 316–347.     

Palaeobotanical remains associated with dinosaur fossils from the Camarillas Formation (Barremian) of Galve (Teruel,Spain)

A well-preserved macroflora and rich palynological assemblages corresponding to the Camarillas Formation (early-middle Barremian) in the San Cristóbal and Galve Mine sites from the Galve sub-basin in northeastern Spain are presented here. These remains represent the first fossil plant evidence from these deposits. Within plant macroremains, the cheirolepidiacean Pseudofrenelopsis aff. varians (Fontaine) Watson has been found. The palynological assemblage yielded well-preserved spores and pollen grains, mainly dominated by the genus Classopollis. Spores are also abundantly represented by schizaeacean spores (Cicatricosisporites and Plicatella). This spore assemblage supports an early-middle Barremian age for these localities. It is noteworthy that small basal angiosperm pollen grains of the genera Crassipollis and Retimonocolpites, together with other indeterminate grains, have been reported here. This flora constitutes the primary food producer for dinosaur at that time, and thus the information of the flora is important for the understanding of the ecological background for the dinosaur evolution during the Early Cretaceous.     

Echinoderm faunas from the Lower Cretaceous (Aptian–Albian) of Alexander Island,Antarctica

Abstract: Strata assigned to the Fossil Bluff Group on Alexander Island, Antarctica, contain Aptian to Albian high‐latitude echinoderm faunas that lived at palaeolatitudes greater than 60 degrees south. The Pluto Glacier Formation, of essentially Aptian age, yields a deep‐water assemblage that includes two ophiuroids, an ophiacanthid and a representative of the ophiolepidid genus Mesophiomusium, both represented by partially articulated specimens. The echinoid fauna includes a new genus of diadematoid, Australidiadema, and a new genus of disasteroid, Notidisaster, which extend the record of both groups into the southern hemisphere. The overlying Neptune Glacier Formation, of late Albian age, yields only spatangoids which are common but rarely well enough preserved to be identified even to genus level, although at least some belong to the genus Hemiaster.     

Lancetfish teeth (Neoteleostei, Alepisauroidei) from the Early Cretaceous of Alcaine, NE Spain

Isolated teeth of fossil lancetfishes (Neoteleostei, Alepisauroidei) are reported from Early Cretaceous strata of the Oliete subbasin (Iberian basin) in NE Spain. These are the oldest remains attributable to alepisauriform teleosts. The fossil-bearing strata are dated as lower Barremian. The teeth were recovered from shallow marine to lagoonal sediments. They closely resemble teeth of the fossil alepisauriforms Enchodus and Cimolichthys in overall morphology. The combination of fang-like morphology, sculpture consisting of apico-basal striations, postapical barb, absence of distal cutting edge, and wide pulp cavity surrounded by a rather thin layer of dentine is interpreted as the most basal tooth pattern in alepisauriforms. These remains may be isolated, but this study emphasizes the true value of such remains for palaeobiological studies, predicting the fossils provide characters for phylogenetic analyses.     

First record ofColoborhynchus (Pterosauria) from the Santana Formation (Lower Cretaceous) of the Chapada do Araripe, Brazil

The anterior tips of associated upper and lower jaws of a pterosaur from the Lower Cretaceous of Brazil are described and assigned to the taxonColoborhynchus in the family Ornithocheiridae. It is characterized by the shape and position of the sagittal crest on the upper and lower jaw, the arrangement and length of the teeth and the spoon-like lateral expansion of the anterior parts of the jaws. It closely resemblesColoborhynchus wadleighi from North America andColoborhynchus clavirostris from England. Diagnostic anatomical characteristics permit a revision of the genusTropeognathus, which is shown here to be a junior synonym of other described taxa.Tropeognathus mesembrinus is referred toCriorhynchus andT. robustus toColoboryhnchus. Consistent anatomical features enable the new jaw fragment to be assigned toColoborhynchus robustus.      

A Chondrophorine (Medusoid Hydrozoan) from the Lower Cretaceous of Chile

Aysenspriggia apelegensis is a new genus and species of a chondrophorine (jellyfish-like hydrozoan) from the Lower Cretaceous Apeleg Formation of southern Chile. Despite their modern abundance chondrophorines are rare in the fossil record. The Apeleg Formation was deposited in a deep-water environment characterised by strong tidal currents. The fossils resulted from water-logged pelagic floats settling to the sea bed during periods of tidal slack water. Burial of the rigid three-dimensional chitinoid float resulted in preservation as imprints on the base of the overlying sandstone. Soft parts of the animal were not preserved. The palaeoenvironmental interpretation is in accordance with that of other records of chondrophorines, including those from the Ediacaran fauna, which are apparently characterised by a bimodal depth distribution. Like much of the Ediacaran fauna most chondrophorines are preserved as impressions on the base of sandstone beds.     

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.     

The lectotype of Sphenobaiera Ikorfatensis (Seward) Florin, a ginkgophyte from the Lower Cretaceous of western Greenland

Use of the genus Sphenobaiera Florin for deeply divided ginkgoalean leaves lacking a petiole is discussed. The type material of the species Sphenobaiera ikorfatensis (Seward) Florin from the Lower Cretaceous at Ikorfat in West Greenland is diagnosed, redescribed and the lectotype designated. The cuticle, which is described and figured in detail for the first time, shows the leaf to be amphistomatic and allows previous identifications of Sphenobaiera ikorfatensis in Lower Cretaceous floras from Siberia and China to be confirmed.