Albian Cenomanian Research Articles

Hispanigalathea raymondcaseyi, a new squat lobster (Crustacea, Decapoda, Galatheoidea) from the Gault (Albian) of Folkestone, England

A new species of galatheoid from the upper Albian (Gault Clay Formation) of Folkestone, Kent (England) described herein, represents the first squat lobster on record from the highly fossiliferous Gault strata in the Anglo-Paris Basin. Normally, squat lobsters are commoner in reef settings of this age. The new species is assigned to the genus Hispanigalathea Klompmaker et al., 2012, which was so far known only from Albian–Cenomanian reef deposits of Navarra, northern Spain.

Transition from Late Jurassic rifting to middle Cretaceous dynamic foreland, southwestern U.S. and northwestern Mexico

AbstractSubsidence history and sandstone provenance of the Bisbee basin of southwestern New Mexico, southern Arizona, and northern Sonora, Mexico, demonstrate basin evolution from an array of Late Jurassic–Early Cretaceous rift basins to a partitioned middle Cretaceous retroarc foreland basin. The foreland basin contained persistent depocenters that were inherited from the rift basin array and determined patterns of Albian–early Cenomanian sediment routing. Upper Jurassic and Valanginian–Aptian strata were deposited in three narrow extensional basins, termed the Altar-Cucurpe, Huachuca, and Bootheel basins. Initially rapid Late Jurassic subsidence in the basins slowed in the Early Cretaceous, then increased again from mid-Albian through middle Cenomanian time, marking an episode of foreland subsidence. Sandstone composition and detrital zircon provenance indicate different sediment sources in the three basins and demonstrate their continued persistence as depocenters during Albian foreland basin development. Late Jurassic basins received sediment from a nearby magmatic arc that migrated westward with time. Following a 10–15 m.y. depositional hiatus, an Early Cretaceous continental margin arc supplied sediment to the Altar-Cucurpe basin in Sonora as early as ca. 136 Ma, but local sedimentary and basement sources dominated the Huachuca basin of southern Arizona until catchment extension tapped the arc source at ca. 123 Ma. The Bootheel basin of southwestern New Mexico received sediment only from local basement and recycled sedimentary sources with no contemporary arc source evident. During renewed Albian–Cenomanian subsidence, the arc continued to supply volcanic-lithic sand to the Altar-Cucurpe basin, which by then was the foredeep of the foreland basin. Sandstone of the Bootheel basin is more quartzose than the Altar-Cucurpe basin, but uncommon sandstone beds contain neovolcanic lithic fragments and young zircon grains that were transported to the basin as airborne ash. Latest Albian–early Cenomanian U-Pb tuff ages, detrital zircon maximum depositional ages ranging from ca. 102 Ma to 98 Ma, and ammonite fossils all demonstrate equivalence of middle Cretaceous proximal foreland strata of the U.S.-Mexico border region with distal back-bulge strata of the Cordilleran foreland basin. Marine strata buried a former rift shoulder in southwestern New Mexico during late Albian to earliest Cenomanian time (ca. 105–100 Ma), prior to widespread transgression in central New Mexico (ca. 98 Ma). Lateral stratigraphic continuity across the former rift shoulder likely resulted from regional dynamic subsidence following late Albian collision of the Guerrero composite volcanic terrane with Mexico and emplacement of the Farallon slab beneath the U.S.–Mexico border region. Inferred dynamic subsidence in the foreland of southern Arizona and southwestern New Mexico was likely augmented in Sonora by flexural subsidence adjacent to an incipient thrust load driven by collision of the Guerrero superterrane.

The leaves of Anabarella Abramova (Pinopsida) from the Cretaceous ofthe north of East Siberia (Russia)

The paper documents in detail the morphology, epidermal features and cuticle ultrastructure of the leaves of the Mesozoic conifer genus Anabarella Abramova 1984. For the first time, the leaf epidermal and cuticle structures of the type species Anabarella kryshtofovichii Abramova from the Albian–Cenomanian (Cretaceous) of the Anabar river basin (East Siberia, Arctic Russia) were studied with the scanning electron (SEM) and the transmission electron (TEM) microscopes. Emended diagnosis for the genus Anabarella and the diagnosis for the species A. kryshtofovichii are provided, since only a description of this species was given in the original publication. Because the holotype has been lost, a lectotype is selected. The cuticular membrane of Anabarella leaves belongs to the type 1 of the cuticle classification of Holloway 1982: it is made up of the cuticle proper A (composed of an outer polylamellate A1 layer and an inner homogeneous A2 layer) and a cuticular fibrillate layer B1. The leaves of Anabarella kryshtofovichii differ from other fossil conifers by a very thick cuticle membrane consisting predominantly of a cuticle proper A; the cuticular layer B1 is less than 1% from the total thickness of cuticular membrane in the ordinary epidermal cells. The studied leaves have both xeromorphic (thick cuticle and sunken stomata) and mesomorphic (amphistomatic leaves, unprotected stomata) features. The mesomorphic features of the Anabarella leaves, as well as the deciduousness, were probably an adaptation to the humid conditions of the mid-Cretaceous Arctic climate with warm and dark winters.

A new species of Heckelichthys from the Muhi Quarry (Albian–Cenomanian) of central Mexico

A new species of ichthyodectiform is presented here. The study is based on 36 fish specimens recovered from the Muhi Quarry, a mid–Cretaceous (Albian–Cenomanian) Fossil-Lagerstätte in Hidalgo, central Mexico. This Mexican taxon is identified as a new species of Heckelichthys due to: presence of an elongated head, second infraorbital being the longest, small teeth, articulation of mandible with the skull anterior to the orbit, small opercle, and ventral arm of the preopercle longer than the dorsal arm. Additionally, Heckelichthys preopercularis sp. nov., differs from the previous known species of Heckelichthys, H. vexillifer and Heckelichthys sp. (Vallecillo) because it exhibits some unique characteristics in the preopercle, including: posteroventral portion of ventral arm long, extending to the level of the posterior edge of the opercle, and dorsal arm short and narrow from its base. Likewise, in the phylogenetic analysis performed here, Heckelichthys preopercularis sp. nov. is placed in the monophyletic group of Heckelichthys, this clade being a derived group of the Cretaceous ichthyodectiforms. Heckelichthys preopercularis sp. nov. shows closer phylogenetic affinities with Heckelichthys vexillifer; this relationship is supported by one synapomorphy, dorsal limb of preopercle short, reaching to level of middle height of opercle. The occurrence of Heckelichthys preopercularis sp. nov. in the Muhi Quarry expands the diversity and distribution of the genus in the western part of the Tethys Sea, and represents the oldest record of the genus in the world.

Noasaurids are a component of the Australian ‘mid’-Cretaceous theropod fauna

The diversity of Australia’s theropod fauna from the ‘mid’-Cretaceous (Albian–Cenomanian) is distinctly biased towards the medium-sized megaraptorids, despite the preponderance of abelisauroids in the younger but latitudinally equivalent Patagonian theropod fauna. Here, we present new evidence for the presence of ceratosaurian, and specifically abelisauroid, theropods from the Cenomanian Griman Creek Formation of Lightning Ridge, New South Wales. A partial cervical vertebra is described that bears a mediolaterally concave ventral surface of the centrum delimited by sharp ventrolateral ridges that contact the parapophyses. Among theropods, this feature has been reported only in a cervical vertebra attributed to the noasaurid Noasaurus. We also reappraise evidence recently cited against the ceratosaurian interpretation of a recently described astragalocalcaneum from the upper Barremian–lower Aptian San Remo Member of the upper Strzelecki Group in Victoria. Inclusion of the Lightning Ridge cervical vertebra and Victorian astragalocalcaneum into a revised phylogenetic analysis focused on elucidating ceratosaurian affinities reveals support for placement of both specimens within Noasauridae, which among other characters is diagnosed by the presence of a medial eminence on the ascending process of the astragalus. The Lightning Ridge and Victorian specimens simultaneously represent the first noasaurids reported from Australia and the astragalocalcaneum is considered the earliest known example of a noasaurid in the world to date. The recognition of Australian noasaurids further indicates a more widespread Gondwanan distribution of the clade outside of South America, Madagascar and India consistent with the timing of the fragmentation of the supercontinent.

Albian–Cenomanian calcareous nannofossils from DSDP Site 364 (Kwanza Basin, Angola): Biostratigraphic and paleoceanographic implications for the South Atlantic

The Albian–Cenomanian was an interval of extreme warmth due to greenhouse climatic conditions, as well as significant changes in the paleogeography and paleoceanography of the oceans, which affected the evolution of marine ecosystems on a global scale. This study analyzed the calcareous nannofossil assemblages from 72 samples that were recovered from Site 364 (Kwanza Basin, Angola), which was drilled by the Deep Sea Drilling Project (DSDP) Leg 40. A total of 103 calcareous nannofossil species were recovered, enabling the identification of biozones (CC 8 to CC 10a; or BC 23 to UC 1b/UC 4a) allowing to assign an Albian–Cenomanian interval for the deposition of the studied section. The recovered assemblages have a subtropical-tropical affinity and are indicative of a surface water connection between the Central Atlantic and the South Atlantic oceans, that extends at least as far as offshore Angola. The area sedimentation was predominantly calcareous and pelagic during this interval, with the exception of the basal section, where Albian black shales interbedded with dolomitic and marly limestones were deposited. Throughout the section, high concentrations of TOC and sulfur and the presence of dissolution-susceptible species likely indicate low euxinic conditions for the Kwanza Basin. Dissolution is a significant process for Site 364 in the majority of the studied samples, although not to the point where species richness was severely impacted, as small amounts of dissolution-susceptible taxa were observed. Dissolution showed a marked decrease in intervals in which paleontological and geochemical data indicated an increase in surface water fertility/productivity.

Microfossil assemblages as key to reconstruct sea-level fluctuations, cooling episodes and palaeogeography: The Albian to Maastrichtian of Boreal and Peri-Tethyan Russia

Abstract The main palaeogeographic features of the Late Cretaceous Eastern European Platform and its southern framework are reconstructed mainly based on micropalaeontological data. An integrated foraminiferal–radiolarian zonation for the Upper Albian–Maastrichtian serves as a basis for palaeogeographic reconstructions and as a framework for the interpretation of palaeoclimate and sea-level trends. The study focuses on time slices of late Albian–Cenomanian, Turonian–Coniacian and Santonian–Campanian intervals. The late Albian was characterized by the gradual disappearance of a meridional seaway and the opening of connections into the Tethys Ocean and parts of the Peri-Tethys seas during the Cenomanian. As a result, mainly carbonate sedimentation prevailed during middle Turonian–Santonian times, characterized by high global sea-level. A cold Boreal water influence can be discerned not only along the northern margin of the Eastern European Platform, but as far south as the Northern Caucasus during certain time intervals, particularly during the Campanian. The Western Siberia Boreal Basin also influenced the study area, giving evidence of cooler-water episodes through the Palaeo-Ural territory and the Turgai Seaway.

Chert–clastic sequence in the Cretaceous Shimanto Accretionary Complex on the central Kii Peninsula, SW Japan

AbstractOcean plate stratigraphy (OPS) within an ancient accretionary complex provides important information for understanding the history of an oceanic plate from its origin at a mid‐ocean ridge to its subduction at a trench. Here, we report a recently discovered chert–clastic sequence (CCS) that comprises a continuous succession from pelagic sediments to terrigenous clastics and which constitutes part of the OPS in the Akataki Complex within the Cretaceous Shimanto Accretionary Complex on the central Kii Peninsula, SW Japan. As well as describing this sequence, we present U–Pb ages of detrital zircons from terrigenous clastic rocks in the CCS, results for which show that the youngest single grain and youngest cluster ages belong to the Santonian–Campanian and are younger than the radiolarian age from the underlying pelagic sedimentary rock (late Albian–Cenomanian). Thus, the CCS records the movement history of the oceanic plate from pelagic sedimentation (until the late Albian–Cenomanian) to a terrigenous sediment supply (Santonian–Campanian).

Palynology from the Cenomanian Mata Amarilla Formation, southern Patagonia, Argentina

The critical climatic changes that occurred during the Albian–Turonian Cretaceous interval led to a major biotic turnover, both in terrestrial and marine ecosystems. Several large-scale palynological works have been conducted in the Northern Hemisphere, but information for the Southern Hemisphere remains scarce. Particularly for southern South America, there are only a few palynological works focused on this important time interval. We report here, a diverse palynoflora recovered from the Cenomanian Mata Amarilla Formation, southern Patagonia, Argentina. The palynological assemblage is composed of 64 species within 47 genera. Three new species are here defined: Polycingulatisporites multiverrucata sp. nov., Clavatisporites cenomaniana sp. nov. and Collarisporites minor sp. nov., and 18 species are first recorded for southern South America. Cluster analysis including several Albian–Turonian palynofloras of middle and high latitudes of eastern and western Gondwana show that Patagonian palynofloras are clustered together, sharing a great compositional similarity, but with features common to those of the Antarctic Peninsula and New Zealand. The Mata Amarilla Formation palynofloras here presented show characteristics of the Cyclusphaera psilata-Classopollis Sub-province, extending its stratigraphic range into the Cenomanian. This palynoflora fits well with the evolutionary scheme of angiosperms previously proposed for Argentina, and adds a new characteristic taxon (cf. Dichastopollenites sp.). The presence of Albian–Cenomanian megaspore species (Arcellites disciformis and Balmeisporites sp. cf. B. holodictyus), the abundance of common elements of the Early Cretaceous Patagonian assemblages (e.g. Classopollis and Cyclusphaera), and the relative scarcity of angiosperm pollen grains support a Cenomanian age for the Mata Amarilla Formation.

Ferrodraco lentoni gen. et sp. nov., a new ornithocheirid pterosaur from the Winton Formation (Cenomanian\u2013lower Turonian) of Queensland, Australia

The Australian pterosaur record is poor by world standards, comprising fewer than 20 fragmentary specimens. Herein, we describe the new genus and species Ferrodraco lentoni gen. et sp. nov., based on the most complete pterosaur specimen ever found in Australia, and the first reported from the Winton Formation (Cenomanian–lower Turonian). The presence of premaxillary and mandibular crests, and spike-shaped teeth with subcircular bases, enable Ferrodraco to be referred to Anhangueria. Ferrodraco can be distinguished from all other anhanguerian pterosaurs based on two dental characters: the first premaxillary and mandibular tooth pairs are small; and the fourth–seventh tooth pairs are smaller than the third and eighth ones. Ferrodraco was included in a phylogenetic analysis of Pterosauria and resolved as the sister taxon to Mythunga camara (upper Albian Toolebuc Formation, Australia), with that clade occupying the most derived position within Ornithocheiridae. Ornithocheirus simus (Albian Cambridge Greensand, England), Coloborhynchus clavirostris (Valanginian Hastings Sands, England), and Tropeognathus mesembrinus (upper Aptian–lower Albian Romualdo Formation, Brazil) were resolved as successive sister taxa, which suggests that ornithocheirids were cosmopolitan during the Albian–Cenomanian. Furthermore, the stratigraphic age of Ferrodraco lentoni (Cenomanian–lower Turonian) implies that anhanguerians might have survived later in Australia than elsewhere.

Syn-depositional continental rifting of the Southeastern Neo-Tethys margin during the Albian–Cenomanian: evidence from stratigraphic correlation

ABSTRACT Albian–Cenomanian successions (Kazhdumi and Sarvak formations) represent remarkable variations in thickness, facies, fauna, and environments throughout the Zagros area. In the Coastal Fars (Charmu section), sedimentological and paleontological data evidence an intrashelf, with depths of 10s–100s m, surrounded by a shallow carbonate platform. Due to its depth, deposition of sequences in this setting has been controlled by eustatic sea-level changes rather than eurybathic changes, and several condensation episodes occurred related to marine transgressions. These observations are different from those in the adjacent sections in the Coastal Fars which recorded subaerial exposures instead. Combined with previous studies, this study denotes several intrashelf basins enclosed by a shallow carbonate platform on the southeastern margin of the Neo-Tethys during the Albian–Cenomanian. Development of intrashelf basins corresponds to basement faults in the Fars Salient. Likely, an extensional tectonic regime associated with a rifting event created horst–graben architecture by exerting extension along the basement faults and reactivating salt structures. Deposition on these troughs and highs led to the facies and thickness variations of the concomitant sequences. Development of several intrashelf basins on the southeastern margin of the Neo-Tethys indicates that syn-depositional continental rifting event could occur during the Albian–Cenomanian, prior to the tectonic inversion around the earliest Turonian.

Cretaceous (Hauterivian–Cenomanian) palaeoceanographic conditions in southeastern Tethys (Matruh Basin, Egypt): Implications for the Cretaceous climate of northeastern Gondwana

Quantitative palynological, sedimentological, and geophysical data analyses of the Cretaceous Abu Tunis 1X well from the Matruh Basin, northwestern Egypt indicate deposition of four major alternating regressive–transgressive successions. Sedimentation was largely affected by the Tethyan 2nd order sea level changes, with minor overprints by regional tectonics. The Lower Cretaceous part of the succession shows regressive sequences of deltafront to delta-top (upper Hauterivian–lowermost upper Barremian), delta channel (upper Aptian–middle Albian), and distal deltaic (upper Albian) settings that were interrupted by transgressive inner–proximal middle shelf deposits (uppermost Barremian–middle Aptian). These sediment packages correspond to Tethyan sea level fall from the late Hauterivian to late Barremian, and to the early–middle Aptian long-term sea level high stand. The Tethyan late Aptian–middle Albian long-term (2nd order) sea level rise was masked by regional late Aptian–Albian uplift, which affected deposition of the later regressive sequence. The Cenomanian shows a change in depositional setting from a proximal inner shelf (lower Cenomanian) to a middle shelf setting (middle–upper Cenomanian), corresponding to the Tethyan long-term latest early–late Cenomanian sea level rise.We demonstrate that northeastern Gondwana (Egypt) experienced different climatic conditions from other parts of the Northern Gondwana Phytogeographic Province. The climate in Egypt shifted from less warm and more humid conditions of the Hauterivian–early Barremian to a warmer and drier climate during the late Barremian–middle Aptian, although never becoming as dry as western Northern Gondwana. Warmer and more humid conditions were reestablished during the late Aptian and became even more accentuated during the Albian–Cenomanian, in contrast to the warm and much drier climate of Northern Gondwana at that time. Turonian climatic conditions may have been less humid as a result of the breakup of the Western Gondwanan supercontinent and the northeasterly drift of the African continent. The climatic conditions experienced in northeastern Gondwana developed through the early-mid Cretaceous as a result of changes in palaeolatitudinal position, variations in sea level, and shifts in the Intertropical Convergence Zone, which drove fluctuations between periods of warm humid and warm dry conditions.

A glance at the deep past history of insects

A glance at the deep past history of insects

Albian–Cenomanian Granitoid Magmatism and Copper Ore Genesis in Sikhote-Alin (Far East, Russia)

Albian–Cenomanian Granitoid Magmatism and Copper Ore Genesis in Sikhote-Alin (Far East, Russia)

Main Types of Aptian–Cenomanian Sedimentary Rocks on Guyots of the Magellan Mountains, Pacific Ocean

The typical rocks composing the base of the sedimentary cover of the guyots on the Magellan Seamounts are described. The upper part of the volcanic basement of the guyots is overlain by Aptian deposits of shallow reef ecosystems represented by terrigenous (beach) and organic-chemical (coral, shell-and-detritus, and oolitic) carbonate rocks. These deposits encircle the western part of the Fedorov and Ilyichev guyots, and the satellite buildings of the Alba and Pallada guyots in the form of an almost complete ring, extending from the edge of the plateau summit to 2500–3000 m depth. Down the slope they are replaced by planktonic (nanoforaminiferal) sediments and edaphogenic breccias. The appearance of pelagic limestone is associated with a sea-level rise during the Late Albian–Cenomanian eustatic transgression. Exposures of reef and planktonic limestones of up to 300 km2 in area are also recorded on some guyots.

Albian–Cenomanian A-type granite-related Ag–Pb–Zn veins in the central Yidun Terrane, SW China: constraints from the Xiasai deposit

The Xiasai–Lianlong metallogenic belt in the central Yidun Terrane (China) hosts several Sn–Ag and (Sn–) Ag–Pb–Zn deposits, which are spatially associated with Cretaceous granites. The Xiasai Ag–Pb–Zn deposit (about 0.27 Mt Pb+Zn, 1028 t Ag, and 20,000 t Sn) is the largest deposit in the belt and is related to a monzogranite intrusion. The deposit consists of sulfides in hydrothermal veins, resulting from three successive mineralization stages (I–III). A Rb–Sr isochron of sphalerite samples yielded an age of 99 ± 3 Ma, and zircon U–Pb laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) dating of the Xiasai monzogranite gave ages between 102 ± 1 and 101 ± 1 Ma. The Xiasai monzogranite has a weakly peraluminous A-type granite composition, with high SiO2, alkali, and FeOt contents and low CaO, MgO, and TiO2 contents. It is marked by enrichments in Rb, Th, and U, with depletions in Ba, Nb, Sr, P, and Ti relative to the primitive mantle. The REE patterns show a negative slope due to LREE enrichment with negative Eu anomalies (Eu/Eu* = 0.1–0.3). The Xiasai monzogranite, with variable eHf(t) values (− 2.7 to 0.6) and Meso- to Neoproterozoic two-stages Hf model ages (TDM2 = 925–1095 Ma), was probably derived from mixing of melts derived from partial melting of the Paleoproterozoic crustal basement and the Early Cretaceous mantle in an extensional tectonic setting. Hydrothermal fluids are characterized by high temperatures (423–481 °C) and salinities (14.9–19.0 wt% NaCl) for Sn mineralization (stage I), moderate temperatures (285–386 °C) and salinities (3.5–8.0 wt% NaCl) for the Cu–Zn mineralization (substage II-2), and low temperatures (158–242 °C) and salinities (3.4–5.7 wt% NaCl) for the Ag–Pb mineralization (substage II-3). The H–O isotopes indicate that the hydrothermal fluid likely has a magmatic component that mixed over time with infiltrating meteoric water and organic matter during fluid–rock interactions. The δ34S values of sphalerite range from − 9.7 to − 3.1‰ and those from galena from − 10.5 to − 4.9‰. The estimated δ34S value of the hydrothermal fluid is − 8.5‰, using the sulfur isotopic fractionation of sphalerite–galena pairs that are interpreted to be in equilibrium. Sulfides from substages II-2 and II-3 have relatively homogeneous Pb isotopic compositions, which are similar with those of K-feldspars from the Xiasai monzogranite. Geochronological and isotope data support a magmatic–hydrothermal origin for the Xiasai Ag–Pb–Zn deposit.

Palaeoclimatic reconstruction for a Cenomanian‐aged angiosperm flora near Schefferville, Labrador

AbstractAn understanding of local and regional climate trends is essential to investigate the remarkable angiosperm radiation that happened during the Albian–Cenomanian transition. However, many of the inland depositional environments pioneered by the first modern angiosperms are poorly represented in the fossil record. Eastern Canada, in particular, has a very poor Mesozoic record. In this paper, we present the first multivariate palaeoclimate analysis (CLAMP) for the environment of a geologically isolated woody dicot dominated flora found in the Redmond no.1 mine, Labrador, near Schefferville, with an estimated Cenomanian age. It reveals that the Redmond flora would have experienced a mean annual temperature of 15.1 ± 2.1°C, one of the coolest recorded for North America at this time. These results confer the Redmond no.1 site a warm temperate and fully humid climate with a hot summer, in accordance with previous qualitative palaeoclimate estimates. This flora fits smoothly into palaeolatitudinal MAT gradients that use other Cenomanian‐estimated North American floras. Despite an inland setting, the climate analysis does not recover a significantly higher degree of seasonality than the sites to which it is compared, which agrees with established climate equability models for the Cretaceous and Palaeogene. This study also introduces 15 new morphotypes discovered in recent fieldwork. The eventual description of the species they represent may refine our dating estimates for the Redmond Formation. A greater understanding of the depositional environment and of the natural history of these angiosperms is required to improve this community's characterization, along with estimates from other proxies.

Priscaplectus gen. nov. and two new species in mid-Cretaceous amber from Myanmar (Coleoptera: Staphylinidae: Pselaphinae)

Fossil taxa of the extant megadiverse subfamily Pselaphinae from Mesozoic deposits are sporadically documented. To date merely six genera and seven species have been reported from the upper Albian Spanish and Albian–Cenomanian Burmese ambers. Herein we describe a new genus, Priscaplectus gen. nov., and two new species, P. carinatus sp. nov. and P. grandiceps sp. nov. (type species), based on twelve specimens entombed in amber from northern Myanmar. The detailed morphologies of the new taxa are explored, especially notable is a nearly complete foveal pattern that is described for the first time for a fossil pselaphine. The integration of Priscaplectus into a phylogenetic context using combined morphological and molecular dataset suggested an affinity to Euplectitae. Nevertheless, due to the unsatisfactory knowledge of the internal tribal relationships, Priscaplectus is left incertae sedis within the higher Pselaphinae.

Isisfordia molnari sp. nov., a new basal eusuchian from the mid-Cretaceous of Lightning Ridge, Australia.

The Australian Mesozoic crocodyliform record is sparse in comparison to other Gondwanan localities. A single formally-named taxon is known from this interval; Isisfordia duncani (Winton Formation, Albian–Turonian, Queensland). We present a previously undescribed crocodyliform braincase from the Griman Creek Formation (Cenomanian), New South Wales, which we assign to Isisfordia molnari sp. nov. Assignment to the genus is based on the possession of a newly-defined autapomorphy of Isisfordia: a broadly exposed prootic within the supratemporal foramen. A second autapomorphy of I. duncani (maximum diameter of the caudal aperture of the cranioquadrate siphonium approximately one-third the mediolateral width of the foramen magnum, with the lateral wall of the caudal aperture formed exclusively by the quadrate) may also be present in I. molnari; however, definitive recognition of this feature is marred by incomplete preservation. The new taxon is differentiated from I. duncani based on the absence of a median ridge on the parietal, and the lack of characteristic ridges on the parietal that form the medial margin of the supratemporal foramina. Reanalysis of a second specimen (the former holotype of the nomen dubium,‘Crocodylus (Bottosaurus) selaslophensis’) allows for its referral to the genus Isisfordia. Crucial to this reappraisal is the reinterpretation of the specimen as a partial maxilla, not the dentary as previously thought. This maxillary fragment possesses specific characteristics shared only with I. duncani; namely an alveolar groove. However, several key features differentiate the maxillary fragment from I. duncani, specifically the presence of continuous alveolar septa, the thickening of the medial alveolar rim, and the alveolar and crown base morphology. These findings constitute the first evidence of Isisfordia outside of the type locality and indicate its widespread occurrence on the freshwater floodplains along the eastern margin of the epeiric Eromanga Sea during the Albian–Cenomanian.

Calcareous nannoplankton proxies for palaeoenvironmental reconstruction of the Albian–Cenomanian succession in North-western Israel (Mount Carmel Region)

Abstract We present data on the calcareous nannofossil distribution in the Albian–Cenomanian borehole CT8 obtained from the Carmel area, NW Israel. The nannofloral assemblage consists of 113 species, with Watznaueria spp. dominating the entire succession. The detailed calcareous nannofossil biostratigraphy of this section is established, and seven nannofossil (sub)zones are recognised. For the first time the age of the Tavasim Tuff (V2) is biostratigraphically identified as Late Albian. The quantitative analysis of the calcareous nannofossils suggests warm, open marine or coastal, mainly oligotrophic conditions throughout the entire succession of borehole CT8, with evident fluctuations of temperatures and fertility and a general trend towards cooling in the uppermost part of the sequence (Middle–Late Cenomanian). Temperature and nutrient variations correspond to those in the western Tethys, thus suggesting at least a supra-regional extent of processes detected in the Carmel Region. The biostratigraphy shows no evidence of hiatuses in the studied section, but the absence of positive carbon isotope anomalies associated with the Oceanic Anoxic Event (OAE) 1d and Mid-Cenomanian Event elsewhere suggests that the OAE 1d is possibly missing in the studied section due to a hiatus around the Isfiye Fm./Arqan Fm. boundary.