Fossil marine vertebrates (Chondrichthyes, Actinopterygii, Reptilia) from the Upper Cretaceous of Akkermanovka (Orenburg Oblast, Southern Urals, Russia)
Upper Cretaceous coastal marine deposits are widespread in the Southern Urals with a number of marine vertebrates previously reported from this region. However, previous studies on the vertebrate faunas in this region often lack detailed taxonomic descriptions and illustrations, rendering comparisons to other faunal assemblages difficult. A new diverse vertebrate assemblage comprising cartilaginous and bony fishes, as well as marine reptiles, is described here from the Orenburg region near Akkermanovka (Southern Urals, Russia). Thirty five taxa are identified, including three holocephalans ( sp., , Chimaeroid indet.), two hybodontiform sharks ( sp., cf. sp.), 17 neoselachians ( cf. sp., sp., ex gr. . cf. ), a holostean (Lepisosteidae indet.), nine teleosts ( sp., Saurodontidae indet., cf. sp., Pachyrhizodontidae indet., . cf. . spp., Alepisauroidei indet.), two plesiosaurs (Polycotylidae indet., Plesiosauria indet.), and one mosasaurid (Tylosaurinae indet.). Based on the faunal assemblage, a Santonian-?early Campanian age is proposed. Lamniform sharks are the best represented group in terms of taxic diversity and relative abundance, probably reflecting the peak in diversity this group experienced following the Cenomanian radiation in the Late Cretaceous. The faunal assemblage of Akkermanovka exhibits significant taxonomic overlaps with assemblages reported from Asia and North America, but not from Southern Hemisphere continents, indicating east-west dispersal of several marine taxa during the Late Cretaceous.
A diverse assemblage of species (Elasmobranchii: Ptychodontidae) from the Upper Cretaceous of Ukraine, with comments on possible diversification drivers during the Cenomanian
New isolated teeth from the Upper Cretaceous of Ukraine and belonging to the extinct durophagous shark are described here. The taxonomic identification of the examined material reveals a quite diverse Cenomanian shark fauna which comprised both cuspidate and un-cuspidate species of from the coastal areas at the north-western margin of the Ukrainian Massif. In addition, from the Turonian of Ukraine is reported here for the first time. The revision of the Ukrainian record of revealed that most specimens described here are the oldest so far known from this part of the European Peri-Tethys. Moreover, the present study highlights the co-occurrence of cuspidate and un-cuspidate and a variety of shelled macroinvertebrates, which inhabited coastal and offshore areas of the European epicontinental seas during the Late Cretaceous. The availability of different prey items is proposed here as one of the possible drivers, in addition to abiotic environmental factors, for the diversification of shark tooth morphologies, and possible trophic partitioning between cuspidate and un-cuspidate species of the genus .
Skeletal remains of the oldest known pseudocoracid shark sp. nov. (Chondrichthyes, Lamniformes) from the Late Cretaceous of Lebanon
A new fossil mackerel shark, sp. nov. (Lamniformes, Pseudocoracidae), is described from the Cenomanian Konservat-Lagerstätte of Haqel, Lebanon. The new species is based on the most complete fossil of this group to date, which comprises an associated tooth set of 70 teeth, six articulated vertebral centra, numerous placoid scales and pieces of unidentifiable mineralized cartilage. The dentition of . sp. nov. is marked by a high degree of monognathic heterodonty but does not exhibit the characteristic "lamnoid tooth pattern" known from other macrophagous lamniform sharks. In addition, . sp. nov. shows differences in tooth microstructure and vertebral centrum morphology compared to other lamniform sharks. These variations, however, are also known from other members of this order and do not warrant the assignment of outside the lamniform sharks. The new fossil is the oldest known pseudocoracid shark and pushes the origin of this group back into the Cenomanian, a time when lamniform sharks underwent a major diversification. This radiation resulted not only in high species diversity, but also in the development of a diverse array of morphological traits and adaptation to different ecological niches. sp. nov. was a small, active predator capable of fast swimming, and it occupied the lower trophic levels of the marine food web in the Late Cretaceous.
gen. et sp. nov. (Pycnodontiformes, lower Turonian) northward migration caused by the Cretaceous Thermal Maximum
A new pycnodont taxon, gen. et sp. nov., from the Turonian of the Lower Saxony Basin of Germany is described and its systematic positions is established based on phylogenetic analyses of three specimens using slightly altered data matrices. All analyses display some differences to previous analyses but show very similar results to each other apart from the interpretation of the position of several taxa such as, e.g., . The new pycnodontiform specimens from northwestern Germany are unambiguously identified as a derived member of Pycnodontidae with close relationships to and ? because of the unique combination of characters. One of the three specimens represents a juvenile form. Its morphological characters are limited, but it shares some characters with gen. et sp. nov. and is consequently allocated to the new taxon. The systematic placement of the new taxon, gen. nov., within Pycnodontidae is surprising since it does not display the one autapomorphic character (postparietal brush-like extension for muscle attachment) previously proposed to define this clade, but rather displays a combination of derived and homoplastic characters indicating that the definition of supra-generic taxa needs to be re-evaluated in the future by including more and new taxa. The distribution of pycnodontiform fishes in the Cretaceous appears to concur with changes in global climatic conditions, where high upper-ocean temperatures and high sea levels allow these fishes to migrate into higher latitudes as evidenced by the occurrence of the new taxon and in the Campanian of Sweden.
Pycnodont fishes (Actinopterygii, Pycnodontiformes) from the Upper Cretaceous (lower Turonian) Akrabou Formation of Asfla, Morocco
The Upper Cretaceous (upper Cenomanian-middle Turonian) Akrabou Formation of Asfla, southeast Morocco is renowned for exceptionally preserved, often three-dimensional bony and cartilaginous fish fossils. Teleosts, rare holosteans and chondrichthyans are well known from the so-called 'Goulmima ichthyological assemblage', however pycnodonts (Actinopterygii, Pycnodontiformes) have received scant attention and remain undescribed until now. Five nominal species are recognised in the assemblage, including two new forms: gen. et sp. nov. and sp. nov. The Italian genus is reported in Morocco for the first time. Specimen taphonomy is examined in the context of substrate consistency and oxygenation of an outer shelf carbonate platform setting. Diversity and ecological disparity of the Goulmima assemblage is revised in regard to trophic partitioning with durophagy seemingly more diverse than previously recognised. Comparisons with other pycnodont-bearing horizons of similar age demonstrate strong faunal affinities between the Asfla pycnodonts and those in the western Tethys and South Atlantic.
An enigmatic Maastrichtian small benthic Foraminifera of the Tarbur Formation (Iran, Zagros zone)
The Maastrichtian carbonates of the Tarbur Formation from the Zagros zone (SW Iran) are very rich in larger Foraminifera. Additionally, smaller benthic Foraminifera occur as well, one of them presented here as gen. et sp. nov. It occurs abundantly at the Mandegan section within two levels corresponding to the lower photic zone. Based on the existence of a central pile along with an umbilical plate, and the lacks of true interiomarginal apertures, likely represented by a perforate surface, the suprageneric placing of gen. nov. remains controversial. The ultimate aperture is represented by a central elongate double-bifid slot that arguably lies on a finely perforated and heavy feathered apertural face. Based on the reduced dimensions and lack of dimorphism the new taxon could be considered an epifaunal or shallow-infaunal r-strategist.
New pycnodontiform fishes (Actinopterygii, Neopterygii) from the Early Cretaceous of the Argentinian Patagonia
Here we describe new pycnodontiform fish material recovered from the marine Agrio Formation (lower Valanginian-lower Hauterivian) of the Neuquén Province in the south-western of Patagonia, Argentina. The new material include an incomplete skull and an incomplete prearticular dentition. The incomplete skull consists of some dermal and endochondral elements as well as dental remains and represents a new large-sized gyrodontid that is referred to a new species, . sp. nov. is characterized by a unique combination of tooth crown ornamentations and tooth shape separating it easily from all known species. The incomplete prearticular dentition shows a tooth arrangement and sculpture that resembles that of "" -the previously only known pycnodontiform in the area. This allows revising this species, which was based on an isolated vomerine dentition and which we refer to a new genus, . The new Patagonian fishes reported here expand the knowledge of South American pycnodontiforms. We hypothesize that meanwhile the new Patagonian genus - - diverged from after it migrated into the eastern Pacific through the Hispanic Corridor during the Late Jurassic, the new species -- most likely diverged from a Central or South American species of Both represent the youngest gyrodontid records and simultaneously the southernmost Early Cretaceous occurrences of pycnodontiform fishes.
, a new genus of basal atelostomate from the Early Cretaceous of Europe and its phylogenetic position
Field work in the Lower Cretaceous of the Dolomites (Italy) has resulted in the recovery of a new genus of 'disasteroid' echinoid, which successively was also discovered in slightly older strata in Northern Hungary. This new genus, , is characterized by its highly modified, disjunct apical disc in which all genital plate except genital plate 2 are reduced or fused. The gonopores (which may be multiple) have shifted and pierce interambulacral plates. Anteriorly ambulacrum III is distinctly sunken and forms a distinct frontal notch, while the posterior end is pointed and features a small sharply defined posterior face bearing the periproct. Two new species are established: sp. nov. from the Upper Hauterivian to Lower Barremian Puez Formation of Northern Italy is characterized by its rudimentary ambulacral pores in the paired ambulacra, high hexagonal ambulacral plates aborally and multiple gonopores in the most adapical plates of interambulacral columns 1b and 4a. sp. nov. from the Lower Hauterivian Bersek Marl Formation of Northern Hungary, in contrast, shows circumflexed ambulacral pores, low ambulacral plates, a single gonopore each in the most adapical plates of interambulacral columns 1b and 4a and a flaring posterior end, with sharp margin and invaginated periproct. In addition to those two species Ooster, 1865 from the uppermost Berriasian to basal Barremian of Switzerland is attributed to the new genus. Despite the poor knowledge on this form it seems to be distinguished from the new species by its smaller ambulacral plates and higher interambulacral/ambulacral plate ratio. Phylogenetic analyses based on previous work by Barras (2007) and Saucède et al. (2007) indicate that the new genus is a highly derived stem-group member of the Atelostomata close to the split of holasteroids and spatangoids. A combined analysis based on a subset of the characters employed in these two studies for the first time results in a fully resolved tree for 'disasteroids'. , shows two notable morphological peculiarities: 1) it is one of the first echinoids to develop fascioles and exhibits a yet unknown type of fasciole circling the periproct, termed circumanal fasciole here; 2) it is extraordinary among echinoderms as its extraxial skeleton is reduced to a single plate, the madreporite (genital plate 2), and because its genital pores pierce axial elements rather than extraxial ones.
Propeamussiidae, Inoceramidae, and other Bivalvia from the Lower Cretaceous Puez Formation (Valanginian-Cenomanian; Dolomites, South Tyrol, Italy)
A bivalve assemblage from the Lower Cretaceous Puez Formation at the type locality, Piz de Puez (Dolomites, South Tyrol, northern Italy) is described. Given the large amount of sedimentary rock screened during the course of this study, the <50 bivalves examined here, although occurring in very low abundance, are considered to represent a reasonably comprehensive sample. The assemblage provides insight into an autochthonous, Mesozoic, deep-water bivalve community, which was dominated by glass scallops. Two species are described as new, n. sp. and the giant n. sp. Presumably, they lived as epifaunal-reclining carnivores and preyed on various meiofauna, occupying a similar ecologic niche as their modern counterparts. Scarce epifaunal, suspension-feeding Inoceramidae entered only by occasional recruitment of larvae into an environment that is inferred to have been characterised by low levels of suspended nutrients.
Early Cretaceous araucarian driftwood from hemipelagic sediments of the Puez area, South Tyrol, Italy
We describe a calcareously permineralised fossil tree-trunk, preserved as driftwood, within hemipelagic sediments of the Cretaceous Puez Formation near Wolkenstein, South Tyrol, Italy. Planktic foraminiferal assemblages recovered from the marls containing the fossil wood indicate a latest middle Albian age. Based on its wood anatomy, the trunk is assigned to and probably has an affinity with the conifer family Araucariaceae. The wood lacks pronounced tree-rings consistent with tree growth within the broad humid tropical belt that existed at that time. The trunk contains cylindrical chambers filled within faecal pellets, demonstrating that oribatid mites infested the tree, either during life, or shortly after death. Prior to final burial, the tree-trunk drifted out into the open sea for a considerable period as indicated by extensive borings assigned to the ichnospecies and produced by teredinid bivalves. Relatively little is known about the Cretaceous floras of Italy, so this new finding fills a gap in our knowledge of the composition and ecology of the vegetation of this region.
Nannofossil biostratigraphy, strontium and carbon isotope stratigraphy, cyclostratigraphy and an astronomically calibrated duration of the Late Campanian Zone
A section from the southern (Austro-Alpine Northern Calcareous Alps) margin of the Penninic Ocean in the NW Tethys realm of Late Campanian age is investigated stratigraphically. Plankton foraminifer and nannofossil biostratigraphy designate the presence of the Zone and the () Zone, and standard nannofossil zones CC21-UC15c and CC22ab-UC15de. The combination of carbon isotope stratigraphy, strontium isotopes, and cyclostratigraphy allows a detailed chronostratigraphic correlation. Periodicity was obtained by power spectral analysis, sinusoidal regression, and Morlet wavelets. The duration of the Total Range Zone is calculated by orbital cyclicity expressed in thickness data of limestone-marl rhythmites and stable carbon isotope data. Precessional, obliquity, and short and long eccentricity cycles are identified and give an extent of c. 806 kyr for the zone. Mean sediment accumulation rates are as low as 1.99 cm/kyr and correspond well to sediment accumulation rates in similar settings. We further discuss chronostratigraphic implications of our data.
New biostratigraphic data on an Upper Hauterivian-Upper Barremian ammonite assemblage from the Dolomites (Southern Alps, Italy)
A biostratigraphic subdivision, based on ammonites, is proposed for the Lower Cretaceous pelagic to hemipelagic succession of the Puez area (Southern Alps, Italy). Abundant ammonites enable recognition of recently established Mediterranean ammonite zones from the upper Hauterivian Zone ( Subzone) to the upper Barremian Zone ( Subzone). Ammonites are restricted to the lowermost part of the Puez Formation, the Puez Limestone Member (ca. 50 m; marly limestones; Hauterivian-Barremian). Numerous ammonite specimens are documented for the first time from the Southern Alps (e.g., Dolomites). Ammonite abundances are clearly linked to sea-level changes from Late Hauterivian to mid Late Barremian times. Abundance and diversity peaks occur during phases of high sea-level pulses and the corresponding maximum flooding surfaces (/ and zones). The ammonite composition of the Puez Formation sheds light on the Early Cretaceous palaeobiogeography of the Dolomites. It also highlights the palaeoenvironmental evolution of basins and plateaus and provides insights into the faunal composition and distribution within the investigated interval. The intermittent palaeogeographic situation of the Puez locality during the Early Cretaceous serves as a key for understanding Mediterranean ammonite distribution.
The late Barremian horizon of the Dolomites (Southern Alps, Italy)
A new trace fossil marker level, the horizon, is proposed for the Lower Cretaceous pelagic to hemipelagic succession of the Puez area (Southern Alps, Italy). The horizon occurs in the middle part of the late Barremian Zone ( Subzone). It is approximately 20 cm thick and restricted to the uppermost part of the Puez Limestone Member (marly limestones; Hauterivian-Barremian; Puez Formation). It is fixed to the top 20 cm of bed P1/204. The grey-whitish limestone bed of the Zone is penetrated by Aptian red marls-siltstones of the Redbed Member. The horizon is documented for the first time from the Southern Alps, including the Dolomites, and can be correlated with other Mediterranean localities. The trace fossil assemblage of this marker bed with the co-occurrence of , and sheds light on the Lower Cretaceous sedimentological history and current system of the Puez area within the Dolomites. It also highlights the palaeoenvironmental evolution of basins and plateaus and provides insights into the late Barremian interval.