On Late Jurassic and Early Cretaceous oysters (Bivalvia,Ostreidae) from northern Siberia

The morphology and taxonomic value of morphological features of Late Jurassic and Early Cretaceous oysters from northern Siberia are considered. A new species, Deltoideum exoticum Kosenko, sp. nov. is described.     

Neocrassinid bivalves (Heterodonta) from the Middle Bathonian (Jurassic) of Kachchh,Western India

Six bivalve taxa belonging to the genusNeocrassina Fischer have been described from Middle Bathonian (Middle Jurassic) rocks of Kachchh, Western India. Of these,Neocrassina (N.) ovata (Smith), TV.(N.) robusta (Etallon) andN. (N.) paphia (d?Orbigny) have been recorded previously from various parts of Europe, whileNeocrassina (N.) pandeyi Maithani is an endemic faunal element as areNeocrassina (N.) sp. A andNeocrassina (N.) sp. B. The generic and sub-generic characters ofNeocrassina are reviewed as are affinities of the taxa with closely related forms from India and other parts of the world.     

Late Cretaceous crocodile remains from Naskal (India): comparisons and biogeographic affinities

Crocodile teeth from the Maastrichtian inter-trappean beds of Naskal (peninsular India) are described here. Because of isolated denticles visible on sufficiently preserved carinae, the presence of a strong heterodonty (in size and shape), and by comparison to crocodile teeth from various taxa, they are considered as representing a ziphodont form with a heterodont dentition. The difference between ziphodont, “false ziphodont” and non-ziphodont dentitions is evaluated. With the help of scanning electron microscope photographs, it is shown that only precise characteristics of the denticles and not the tooth shape, allow to distinguish the three categories. These three categories do not correspond to monophyletic groups. It is also shown that the “alligatorid” heterodonty, meso- or eusuchian in grade, exists in each category. Although the ziphodont dentition is not sufficient to allow a taxonomical definition, the peculiarities that it often presents, depending on the taxa as well as the teeth shape, enable systematic approaches. An examination of previous works on the possible ziphodont crocodiles from the Tertiary deposits of the Indian subcontinent and on Naskal teeth demonstrate that the latter are closer to those of some Gondwanan crocodiles of mesosuchian grade, known from the early Cretaceous of Africa and possibly a form from the late Cretaceous of Madagascar. They are excluded from eusuchian Laurasiatic as well as Paleogene forms of the Indian subcontinent, either ziphodont or not. Contrary to the earlier works on the inter-trappean crocodiles, the present study removes this group as one of the evidences in support of an early (late Cretaceous-early Tertiary) India/Asia collision model. In fact, it provides an additional support for the existence of possible Cretaceous biogeographic links between India, Madagascar, Africa, and South America.     

Larval morphology of the brooding clam Lasaea adansonii (Gmelin, 1791) (Bivalvia, Heterodonta, Galeommatoidea)

The strongly modified mode of development of the small and brooding galeommatoid bivalve Lasaea adansonii (Gmelin, 1791) [syn. Lasaea rubra (Montagu, 1803)] has been studied by means of transmission and scanning electron microscopy and by fluorescent staining of the muscular system and of two neurotracers, FMRFamide and serotonin. In addition, two developmental stages were visualized using computer-aided 3D-reconstruction. All larval stages of L. adansonii lack ciliary rings. The apical organ appears invaginated: the base of the duct contacts the cerebral ganglia and opens on the preoral region. Larval protonephridia are lacking. The adult kidneys develop independently of the pericardial cavity and contain a protonephridial part that enables excretory function until the pericardium is formed. The larval muscular system is composed of smooth muscle fibers; striated fibers are lacking. Posteriorly and immediately below the ligament, a paired cell of unknown function is present that contains serotonin and FMRFamide. In summary, L. adansonii exhibits the direct mode of development. Only few truly larval structures (e.g., the modified apical organ) are elaborated.     

Ethological and environmental significance of Bergaueria hemispherica from the Late Cretaceous of the Bagh Group,Western India

The probable trace maker of B. hemispherica is the fact that one encounters different age groups of sea anemone burrows extended at variable depths in soft, unconsolidated, non-fluidized mud to get stability. It occurs as densely packed, vertical to subvertical, usually unornamented, occasionally showing faint, thin, ring-like structures, allochemic sandstone-filled cylinders with hemispherical base extending to variable depths in the shale. The diameter-to-height ratio calculated for 44 burrow specimens shows that the diameters of most of the specimen are smaller than their height. The probable trace maker of B. hemispherica is the fact that one encounters different age groups of sea anemones, which extended their column at variable depth in soft, unconsolidated, non-fluidized mud to get stability. The inclined nature of paired burrows towards each other suggests social aggression while unpaired inclined burrows suggest swaying in search of food. The monodominant occurrence of B. hemispherica as pre-storm colonization of r-selected organisms (sea anemones) suggest sstressed environment and simultaneous vacation of the burrower reflects rapid sedimentation due to high-energy storm events. Further, storm and inter-storm events deposited sandy allochemic limestone and shale series, respectively, but did not form an identical condition for the colonization of the sea anemone. The species B. hemispherica of the Bagh Group revealed physicochemical parameters (energy conditions, turbidity, sedimentation rate, bathymetry, suspended organic matter, substrate consistency, oxygen, and salinity) of the Late Cretaceous transgressive sea.     

Late Cretaceous to early tertiary Dinoflagellate cysts from Narasapur Well-1, Godavari-Krishna basin,South India

Dinoflagellate cyst assemblages are described fromsome of the richest horizons in the Narasapur Well-1, Godavari-Krishna basin, Andhra-Pradesh, India. Twenty-five taxa belonging to nineteen genera are recorded. The majority exhibit close morphological similarity with species described earlier from Europe, North America and Australia. One new genus, Godavariella, and three new species, Godavariella venkatachalae, Fibrocysta variabilis and Cyclonephelium indicum, are proposed; several more new forms are described but, since meagrely represented, are not named. The dinoflagellate assemblages, along with spore and pollen studies carried out earlier by Venkatachala & Sharma (1984), suggest a Late Cretaceous (Maastrichtian) to Early Tertiary (Palaeocene) age for these sediments.     

Lamniform Shark Teeth from the Late Cretaceous of Southernmost South America (Santa Cruz Province,Argentina)

Here we report multiple lamniform shark teeth recovered from fluvial sediments in the (Campanian-Maastrichtian) Cerro Fortaleza Formation, Santa Cruz Province, Argentina. This small tooth assemblage is compared to various lamniform sharks possessing similar dental morphologies, including Archaeolamna, Cretalamna, Dwardius, Dallasiella, and Cretodus. Although the teeth share numerous morphological features with the genus Archaeolamna, including a developed neck that maintains a relatively consistent width along the base of the crown, the small sample size and incomplete nature of these specimens precludes definitive taxonomic assignment. Regardless, the discovery of selachian teeth unique from those previously described for the region broadens the known diversity of Late Cretaceous South American sharks. Additionally, the discovery of the teeth in fluvial sandstone may indicate a euryhaline paleobiology in the lamniform taxon or taxa represented by this tooth assemblage.     

A molecular phylogeny of Heterodonta (Bivalvia) based on small ribosomal subunit RNA sequences

Within Heterodonta, phylogenesis has so far been studied almost exclusively on the basis of morphological data. Results have often been discordant, and an exhaustive molecular approach has not yet been attempted. The present study was undertaken to clarify the phylogenetic relationships obtaining among Heterodonta families through the analysis of 18S rRNA gene. To do this, the whole sequence of this gene was analyzed in 29 species of eight superfamilies of the order of Veneroida (Arcticoidea, Cardioidea, Galeommatoidea, Mactroidea, Solenoidea, Tellinoidea, Tridacnoidea, and Veneroidea) and in two superfamilies of Myoida (Pholaloidea and Myoidea). The study was extended by constructing phylogenetic trees using partial sequences. This strategy made it possible to include 11 additional species by introducing three further superfamilies: Chamoidea, Corbiculoidea, and Hiatellinoidea. At variance with the conclusions reached on the basis of morphological features, the molecular data clearly show that the Myoida species included in this study belong to Veneroida, thus undermining the legitimacy of the division of Heterodonta into two orders, and that considerable differences in the phylogenetic relationships obtain among superfamilies.     

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.     

Facies pattern and sea-level dynamics of the early Late Cretaceous transgression: a case study from the lower Danubian Cretaceous Group (Bavaria,southern Germany)

The facies development and onlap pattern of the lower Danubian Cretaceous Group (Bavaria, southern Germany) have been evaluated based on detailed logging, subdivision, and correlation of four key sections using an integrated stratigraphic approach as well as litho-, bio-, and microfacies analyses. Contrary to statements in the literature, the transgressive onlap of the Regensburg Formation started in the Regensburg–Kelheim area already in the early Early Cenomanian Mantelliceras mantelli ammonite Zone and not in the Late Cenomanian. In the Early Cenomanian, nearshore glauconitic-bioclastic sandstones prevailed (Saal Member), followed by Middle to lower Upper Cenomanian mid-shelf siliceous carbonates intercalated with fine-sandy to silty marls (Bad Abbach Member). Starting in the mid-Late Cenomanian (Metoicoceras geslinianum ammonite Zone), a considerable deepening pulse during the Cenomanian–Turonian Boundary Event (CTBE) initiated the deposition of the deeper shelf silty marls of the Eibrunn Formation, which range into the early Early Turonian. During the CTBE transgression, also the proximal Bodenwöhrer Senke (ca. 40 km NE of Regensburg) was flooded, indicated by the onlap of the Regensburg Formation onto Variscan granites of the Bohemian Massif, overlain by a thin tongue of lowermost Turonian Eibrunn Formation. A detailed record of the positive δ¹³C excursion of the global Oceanic Anoxic Event (OAE) 2 has been retrieved from this shallow-water setting. An integrated approach of bio-, event-, carbon stable isotope and sequence stratigraphy was applied to correlate the sections and to decipher the dynamics of this overall transgressive depositional system. The Cenomanian successions show five prominent unconformities, which correlate with those being known from basins in Europe and elsewhere, indicating their eustatic origin. The rate of sea-level rise during the CTBE suggests glacio-eustasy as a driving mechanism for Late Cenomanian sea-level changes. The Regensburg and Eibrunn formations of the lower Danubian Cretaceous Group are highly diachronous lithostratigraphic units. Their regional distribution and northeast-directed onlap pattern onto the southwestern margin of the Bohemian Massif can readily be explained by the lateral movements of roughly coast-parallel (i.e., NW/SE-trending) facies belts of a graded shelf system transgressing on a northeastward-rising substrate. It took the Cenomanian coastline ca. 6 Ma to transgress from southwest of Regensburg to the topographically elevated granite cliffs southeast of Roding in the Bodenwöhrer Senke (=60 km distance).     

Reconstruction of Late Cretaceous coastal paleotemperature from halite deposits of the Late Cretaceous Nongbok Formation (Khorat Plateau,Laos)

Cretaceous evaporites of the Maha Sarakhan Formation in Thailand (e.g., the Nongbok Formation, Laos) have been studied for almost a century as the huge potash deposits in the world. The consistently high local paleotemperatures should lead to huge salt deposits during the evaporation process. Primary fluid inclusions in halite can provide surface brine water temperatures directly and quantitatively. Until now, there have been no data published from paleotemperature of primary fluid inclusions of Cretaceous halite. The non-marine halite from the Cretaceous Nongbok Formation (Laos) precipitated from shallow brine waters with temperatures of 17.7–42.3 °C.     

Protaxodioxylon from the Late Jurassic to Early Cretaceous Kota Formation,Pranhita-Godavari Basin,India

Paleontological Journal - The xylotomy of the silicified wood from the Late Jurassic to Early Cretaceous Kota Formation of the Pranhita-Godavari Basin is studied and its systematic affinity is...     

Chondrichthyans from a Cenomanian (Late Cretaceous) bonebed,Saskatchewan, Canada

Abstract: Acid preparation of samples of a bonebed from the Cenomanian of central Canada yielded several thousand well‐preserved chondrichthyan teeth, in addition to numerous other vertebrate remains. Teeth and other remains of one species of chimaeroid, one species of hybodont shark, three species of Ptychodus, 10 species of neoselachian sharks and two species of batoid were recorded. The family Archaeolamnidae fam. nov., genera Meristodonoides gen. nov. and Telodontaspis gen. nov. and species Ptychodus rhombodus sp. nov., Telodontaspis agassizensis gen et sp. nov., Eostriatolamia paucicorrugata sp. nov., Roulletia canadensis sp. nov., Cretorectolobus robustus sp. nov. and Orectoloboides angulatus sp. nov. are described. Status of the genus Palaeoanacorax and the species Cretoxyrhina denticulata, Squalicorax curvatus and ‘Rhinobatos’incertus are discussed, and reconstructed dentitions of Archaeolamna and Roulletia presented. The fauna is of low diversity and dominated by active hunters, with many species apparently endemic to the northern Western Interior Seaway.     

Lindholmemydid turtles (Cryptodira: Testudinoidea) from the Late Cretaceous of Shandong Province,China

A new genus and new species of lindholmemydid turtle (Cryptodira: Testudinoidea), Shandongemys dongwuica n. g. and n. sp. are described on the basis of a partial skeleton with incomplete shell and skull, complete lower jaws and disarticulated limb bones from the Upper Cretaceous Wangshi Group of Zhucheng, Shandong Province, China. Among Lindholmemydidae, the new species is closely related to Mongolemys elegans from the Late Cretaceous of Mongolia. An incomplete shell from the same locality is referred as Lindholmemydidae indet. Glyptops sp. from the Upper Cretaceous Wang Group of Jingangkou, Laiyang, Shandong is revised and assigned to Lindholmemydidae.     

An associated partial skeleton of Jainosaurus cf. septentrionalis (Dinosauria: Sauropoda) from the Late Cretaceous of Chhota Simla,Central India

Abstract: The Cretaceous dinosaur fauna of Indo‐Pakistan has remained poorly understood because of a lack of associated and articulated remains, proliferation of named species, and an incomplete understanding of the dinosaur clades present (e.g. abelisaurid theropods; titanosaur sauropods). Continued work on existing collections, and new discoveries of dinosaur material from India, Pakistan and elsewhere in Gondwana, has begun to resolve the composition and affinities of Indo‐Pakistani dinosaurs. Here, we provide archival evidence that documents associations between postcranial remains of a sauropod collected from Chhota Simla, India by C. A. Matley in the 1930s and later described as ‘Titanosaurus sp.’ This partial skeleton, which represents only the fifth such documented association from Indo‐Pakistan, is referable to Jainosaurus cf. septentrionalis and provides a fuller understanding of its anatomy and phylogenetic affinities.     

OnPlacenticeras mintoi Vredenburg 1908, from the Bagh Beds (Cretaceous) of India

In 1908Vredenburg studied the ammonites collected from the Cretaceous Bagh Beds of India and created the new speciesPlacenticeras mintoi. The author has revised the types of this species, has specified the Lectotype ofP. mintoi and has found that not only this species but alsoHypengonoceras vredenburgi does occur in the Bagh Beds.     

A Late Cretaceous Chimaerid (Chondrichthyes, Holocephali) from Seymour Island, Antarctica

A chimaerid holocephalian, Chimaera zangerli sp. nov., is described from both palatine tooth plates, two tooth plate fragments, and part of the chondrocranium in a nodule from the Maastrichtian of Antarctica. Possibly the oldest known chimaerid, C. zangerli sp. nov. exhibits a tooth plate which is a morphological intermediate between that of the Jurassic Ganodus and the Oligocene C. rupeliensis . The presence of C. zangerli sp. nov. before the end of the Cretaceous is evidence of the early evolution of the Chimaeridae, considered the most derived of the chimaeroid fishes.     

Additional dinosaur teeth from the Cenomanian (Late Cretaceous) of Charentes,southwestern France

Some isolated teeth of theropod and sauropod dinosaurs from the Cenomanian (Late Cretaceous) of Charentes are described. Two new teeth of Troodontidae confirm the presence of this theropod family, previously based on a single specimen. New dental morphotypes are recognized within Dromaeosauridae and Brachiosauridae in comparison with those already known from Charentes. Lastly, a very small tooth is tentatively assigned to an embryonic or neonatal sauropod. The palaeobiogeographical history of European hadrosauroids is briefly discussed. This history was probably more complex than it appears, involving exchanges with both North America and Asia as early as the mid-Cretaceous (Albian–Cenomanian).     

New enantiornithine bird (Aves, Ornithothoraces) from the Late Cretaceous of NW Argentina

A new enantiornithine bird, Intiornis inexpectatus gen. et sp. nov, is described here. It is based on a partial hind limb found in beds of the Upper Cretaceous Las Curtiembres Formation (Campanian), North-West Argentina. The new taxon is referred to the family Avisauridae on the basis of its cranially convex third metatarsal. Several features suggest close relationships between Intiornis and the avisaurid Soroavisaurus, from the Lecho Formation (Maastrichtian; North-West Argentina). Intiornis was the size of a sparrow, thus representing the smallest Enantiornithes known from South America. The new species shows adaptations for a perching mode of life. Moreover, the hypothesis suggesting that the flying pterosaur reptiles decrease in taxonomic diversity due to competitive interaction with birds is discussed. The new species shows adaptations for a perching mode of life. Moreover, the hypothesis suggesting that the flying pterosaur reptiles decrease in taxonomic diversity due to competitive interaction with birds is discussed.