Turns out Sauropods Liked Pasta

First sauropod bones from Italy offer new insights on the radiation of Titanosauria between Africa and Europe

Authors:

Dal Sasso et al

Abstract:

Here we describe the first sauropod skeletal remains from the Italian peninsula that also represent the earliest record of titanosaurs in Southern Europe. Scattered bones, including an almost complete anterior caudal vertebra, were found in Cretaceous (Aptian–Albian) marine deposits, some 50 km East of Rome. The vertebra shows a bizarre and perhaps unique orientation of the zygapophyseal articular facets that renders their interpretation problematic. Phylogenetic retrofitting tests support the placement of the Italian titanosaur among basal lithostrotians. Palaeobiogeographic analysis based on the resulting phyletic relationships suggests an Afro-Eurasian route for the ancestors of the Italian titanosaur, a scenario compatible with the palaeogeographic evolution of the Italian microplates during the Cretaceous. Together with previously recorded titanosaurian-like ichnites from a Cenomanian locality in Latium, this new find suggests a quite long emersion for the Apenninic carbonate platform. We suggest that the Italian titanosaur was member of a population that crossed the western Tethys Sea through a “filtering bridge” composed of a chain of ephemeral islands and peninsulae, known as Periadriatic (Adria) carbonate platforms, that connected sporadically Africa and Europe since the Early Cretaceous.

Glacial dropstones in the western Tethys during the late Aptian–early Albian cold snap

Glacial dropstones in the western Tethys during the late Aptian–early Albian cold snap: Palaeoclimate and palaeogeographic implications for the mid-Cretaceous

Authors:

Rodríguez-López et al

Abstract:

The late Jurassic–early Cretaceous is commonly considered the only cold climatic interval in Earth history without any direct evidence of polar ice. A newly discovered dropstone-bearing interval from the subtropical Iberian Basin (western Tethys) is described and provides evidence of contemporaneous polar glaciation. This interval is correlated laterally for 4.8 km and contains a boulder and two cobble-sized quartzite dropstones that are encased in mid-Cretaceous fissile black shales and fine-grained sandstones. Based on previously published dimensions of similar large clasts, only glacial dropstones and impact ejecta blocks reach the dimensions of the boulder-sized dropstone reported from Iberia. The dropstones show morphological features compatible with glacial transport and abrasion in a subglacial setting which closely resembles the features observed in recent glacial boulders exposed near the snouts of glaciers in Iceland. These Late Aptian dropstones from Spain correlate with many other similar erratics in the northern and southern palaeohemispheres, and suggest that ice sheets formed around the palaeo-North Pole during certain periods of the early Cretaceous. Our results and associated evidence such as the occurrence of glendonites, tillites, moderate- to high-amplitude sea-level oscillations worldwide, minimum pCO2 concentrations, variation in calcareous nannofossil assemblages from low and high latitudes and isotopic excursions suggest that during the mid-Cretaceous there were periods of ice growth and decay that influenced the palaeotemperature, palaeoecology and sedimentology of the marine realm. The new data from Iberia are supported by recent results from Arctic Canada that indicate cool shelves and a mid-Cretaceous cold snap that developed for ~ 6 Myr between 118 and 112 Ma. The late Aptian dropstones reported in eastern Iberia were likely transported from high northern latitudes towards subtropical ones in the western Tethys by an extreme iceberg drift similar to those occurring at the present day in the Atlantic Ocean. Icebergs released from a northern fringing ice sheet may have travelled southwards through the Greenland–Norwegian Seaway.

Evidence for an Aptian Cretaceous Carbon Perturbation in China

Lacustrine sedimentary record of early Aptian carbon cycle perturbation in western Liaoning, China

Authors:

Zhang et al

Abstract:

The early Aptian abrupt carbon isotope excursion in marine carbonate and sedimentary organic matter reflects a major perturbation in the global carbon cycle. However, until now almost all the evidences of this event came from marine deposits. Here we present organic-carbon isotope (δ13Corg) data from the non-marine Jehol Group in western Liaoning, China. The lacustrine δ13Corg curve is marked by a relative long-lasting δ13Corg minimum followed by two stages of positive δ13Corg excursions that are well correlated with contemporaneous marine records. The carbon isotope correlation shows that the lacustrine strata of the Jehol Group were deposited at the same time of the early Aptian Oceanic Anoxic Event (OAE1a). The relative long-lasting δ13Corg minimum supports the hypothesis that volcanic CO2 emission may have played the main role in triggering the negative δ13C excursion and global warming at the onset of this event. In addition, the onset of δ13Corg minimum is concomitant with the radiation of the Jehol Biota, implying that the evolutionary radiation of the Jehol Biota may have been closely related with the increase in atmospheric CO2 and temperature.

Potentially NO Aptian and Albian Cretaceous Atmospheric CO2 changes during oceanic anoxic events

Aptian and Albian atmospheric CO2 changes during oceanic anoxic events: Evidence from fossil Ginkgo cuticles in Jilin Province, Northeast China

Authors:

Sun et al

Abstract:

The Early Cretaceous was a time with super-greenhouse conditions and episodic global oceanic anoxic events. However, relative timing of atmospheric CO2 emissions and oceanic anoxic events, and their causal relationships remain matters of debate. Using the stomatal index approach, well-preserved fossil cuticles of Ginkgo from the Lower Cretaceous Changcai Formation, eastern Jilin, and from the Lower Cretaceous Yingcheng Formation, central Jilin, Northeast China, were investigated to reconstruct atmospheric CO2 concentrations during the Aptian and earliest Albian (Early Cretaceous). The results indicate that the CO2 concentrations reached 1098–1142 ppmv (Carboniferous standardization) or 970–1305 ppmv (regression function) during the Aptian and earliest Albian. Our estimates of palaeoatmospheric CO2 concentrations during the earliest Albian (OAE 1b) are slightly higher than the data between the early Aptian Selli (OAE 1a) and the middle Aptian Fallot OAEs; this may indicate the absence of any great emissions of CO2 during the latest Aptian and earliest Albian.

Montirictus kuwajimaensis: a new Tritylodontid Mammaliamorph From Barremian/Aptian Cretaceous Japan

A new Early Cretaceous tritylodontid (Synapsida, Cynodontia, Mammaliamorpha) from the Kuwajima Formation (Tetori Group) of central Japan

Authors:

Matsuoka et al

Abstract:

We describe tritylodontid remains from the Lower Cretaceous Kuwajima Formation (Tetori Group) in central Japan as representing a new genus, Montirictus kuwajimaensis, gen. et sp. nov. Montirictus is a medium-sized tritylodontid genus characterized by upper cheek teeth having the cusp formula 2-2-2 with subequal cusps, buccal and lingual cusps retaining a crescentic shape with both buccal and lingual ridges anteriorly, and ‘V’-shaped buccolingual cross-sections of two anteroposterior grooves between the three cusp rows. Tentative dating of the Kuwajima Formation to the Barremian–Aptian makes it the stratigraphically youngest representative of a long-lived, globally distributed and abundant mammaliamorph lineage and extends the known geographic range of tritylodontids.

Why did the Stegosaurs go Extinct in the Cretaceous?

Without doubt, stegosaurs were adversely affected by new conditions in the Cretaceous. Available data suggests that, right after their Jurassic heyday, stegosaurs suffered a loss of diversity similar to what sauropods endured - 57-89%. After this first setback, they were further battered, by Barremian time c. 127 Ma. Plated dinosaurs apparently vanished everywhere, except in Asia, where their last occurrences are dated Aptian-Albian. By mid K at the latest, Stegosauria was entirely gone. What caused plated beasts to wane and die out?

In their 2009 paper, Diversity patterns amongst herbivorous dinosaurs and plants during the Cretaceous, Butler et al. note an apparent correlation between the waning of certain plants (cycads, cycadophytes and bennattitalles) and the demise of stegosaurs. Citing earlier works suggesting an ecological association of plated dinosaurs and cycads (and close relatives) they suggest the disappearance of stegosaurs, from the start of the early Cretaceous to its end, mirrored the decline of such vegetation.

With their narrow snouts, stegosaurs do appear to have been specialized feeders, essentially limited to a specific type of plant. Ergo, they may have been vulnerable to loss of such flora. The available evidence however, suggests other factors may have been equally important, if not more so.

link.

Feitianius paradisi: a new Ornithothoracid Enantiornithine Bird With Elaborate Tail Ornamentation From Aptian Cretaceous China

A new Early Cretaceous enantiornithine (Aves, Ornithothoraces) from northwestern China with elaborate tail ornamentation

Authors:

O'Connor et al

Abstract:

We provide a detailed description of a well-preserved enantiornithine specimen (GSGM-05-CM-004) from the Lower Cretaceous (Aptian) Xiagou Formation of northwestern Gansu Province, China, for which we erect the new taxon Feitianius paradisi, gen. et sp. nov. This specimen has a distinctive pelvic morphology and can be further distinguished from all other Mesozoic birds by a unique caudal plumage formed by multiple rectricial morphotypes. This newly documented tail morphology reveals a previously unrecognized level of complexity in the plumage of basal birds. This complex tail-feather morphology has a parallel in extant sexually dimorphic birds in which the males have the most altered tails; thus, we identify this specimen as male. Ornamental tail morphologies, such as the novel tail plumage described here, dominate Enantiornithes. This reinforces hypotheses that sexual selection was a major driving force in the evolution of basal bird plumage.

Liaoningopterus gui: a new Toothed Pterosaur From Aptian Cretaceous China

A new toothed pteranodontoid (Pterosauria, Pterodactyloidea) from the Jiufotang Formation (Lower Cretaceous, Aptian) of China and comments on Liaoningopterus gui Wang and Zhou, 2003

Authors:

Rodrigues et al

Abstract:

Pteranodontoids consist of a diverse and cosmopolitan clade of Cretaceous pterodactyloid pterosaurs. In the Jiufotang Formation (Lower Cretaceous, Aptian) of northeastern China, pterodactyloids are represented by azhdarchoids and pteranodontoids, including istiodactylids and anhanguerians. Here, we describe a new pterosaur from this unit that represents a new species of toothed pteranodontoid. Its overall morphology is consistent with other toothed pteranodontoids but shows some interesting features such as the orbit being more ventrally positioned than in all other species from this clade. It differs markedly from all other pterosaurs from this unit, including Liaoningopterus, Guidraco and Ikrandraco, with which the new taxon is possibly related. In addition to the description of the new taxon, we also describe the anhanguerid Liaoningopterus gui in more detail. The new species, Liaoningopterus gui, Guidraco venator and Ikrandraco avatar, are large pterosaurs with very distinct tooth morphologies, suggesting that they had different prey preferences, partially explaining how the Jiufotang Formation could bear such a high diversity of pterosaur species.

Comparing the Barremian/Aptian Cretaceous Ecologies of the Jehol and Wealden Biotas

A comparison of Barremian–early Aptian vertebrate assemblages from the Jehol Group, north-east China and the Wealden Group, southern Britain: the value of microvertebrate studies in adverse preservational settings

Author:

Sweetman

Abstract:

Vertebrates are a highly significant component of the Jehol Biota of northern Hebei, western Liaoning, and southeastern Inner Mongolia. Furthermore, Jehol vertebrate fossils from these areas are remarkable for their abundance and diversity, and for their taphonomy which has resulted in the preservation of large numbers of complete skeletons and of soft tissues including the feathers of birds and nonavian dinosaurs. In contrast, and also for taphonomic reasons, skeletons are extremely rare in the approximately coeval (Barremian–earliest Aptian) Lower Cretaceous Wealden Group of the Isle of Wight, southern England, UK. However, collection of isolated macro-remains over a period of almost 200 years has demonstrated that the Wealden Group, and in particular the Barremian Wessex Formation, contains Europe’s most diverse dinosaur assemblage. This assemblage, until the relatively recent discovery of China’s feathered nonavian dinosaurs and birds, appeared to be of comparable diversity to that of the Jehol Biota. Isolation of microvertebrate remains in an ongoing study commenced in 2002 has demonstrated that not only is the Wealden Group dinosaur assemblage more diverse than apparent from macro-remains and that it includes birds but also that it includes a high diversity of other aquatic, amphibious and terrestrial vertebrates. It is, therefore, now possible to make meaningful comparisons between the Jehol Biota and that of the Wealden Group of the Isle of Wight. Similarities and marked differences are apparent that reflect geographical separation, palaeoenvironmental factors and the remarkably small outcrop area available for the Wealden Group.

Muiscasaurus catheti: A new Ophthalmosaurid Ichthyosaur From Barremian/Aptian Cretaceous Colombia

A new ophthalmosaurid ichthyosaur from the Early Cretaceous of Colombia

Authors:

Maxwell et al

Abstract:

Cretaceous ichthyosaurs were relatively diverse in temperate latitudes, but few species have been described from the palaeotropics. Here, we describe a new ophthalmosaurid ichthyosaur, Muiscasaurus catheti gen. et sp. nov., from the Barremian–Aptian aged Paja Formation of Colombia. This species is known only from a partial skull and differs from all other ichthyosaurs in the unusual configuration of the external narial opening, slender rostrum, narrow postorbital region, and gracile dentition. It is the second ichthyosaur described from the Paja Formation, suggesting moderate taxonomic and ecological ichthyosaur diversity in the region during the Early Cretaceous.

A Link Between the Cooler, Drier Aptian Cretaceous Climate and Carbonate Production Ending?

Cool episode and platform demise in the Early Aptian: New insights on the links between climate and carbonate production

Authors:

Bonin et al

Abstract:

The Early Aptian encountered several crises in neritic and pelagic carbonate production, major perturbations in the carbon cycle, and an Oceanic Anoxic Event (OAE1a). Yet the causal links between these perturbations and climate changes remain poorly understood, partly because temperature records spanning the Early Aptian interval are still scant. We present new δ18O data from well-preserved bivalves from a carbonate platform of the Galve sub-Basin (Spain) that document a major cooling event postdating most of OAE1a. Our data show that cooling postdates the global platform demise and cannot have triggered this event that occurred during the warmest interval. The warmest temperatures coincide with the time-equivalent of OAE1a and with platform biotic assemblages dominated by microbialites at Aliaga as well as on other tethyan platforms. Coral-dominated assemblages then replace microbialites during the subsequent cooling. Nannoconids are absent during most of the time-equivalent of the OAE1a, probably related to the well-known crisis affecting this group. Yet they present a transient recovery in the upper part of this interval with an increase in both size and abundance during the cool interval portion that postdates OAE1a. An evolution toward cooler and drier climatic conditions may have induced the regional change from microbial to coral assemblages as well as Nannoconids size and abundance increase by limiting continent derived input of nutrients.

Did a Magma Injection Into Organic Sediments at the Barremian/Aptian Boundary Release Carbon Gases, Trigger Oceanic Anoxic Event 1a?

The Early Cretaceous Barents Sea Sill Complex: Distribution, 40Ar/39Ar geochronology, and implications for carbon gas formation

Authors:

Ploteau et al

Abstract:

Mafic igneous rocks of Cretaceous age (80–130 Ma) scattered around the Arctic Ocean are commonly referred to as the High Arctic Large Igneous Province (HALIP). We have mapped out the distribution of HALIP igneous rocks in the Barents Sea region over the past decade based on integrated seismic–gravity–magnetic interpretation, field work, review of publications, and analyses of new and vintage borehole and field samples. The mapping reveals abundant igneous rocks in the northern and eastern Barents Sea covering an area of ~ 900,000 km2 with a conservative volume estimate of 100,000 to 200,000 km3 of intrusions. The igneous province is dominated by sheet intrusions injected into Triassic and Permian sedimentary rocks. Hydrothermal vent complexes are rare, and only two potential vent complexes have been identified on seismic data in the eastern Barents Sea. We have further done extensive radiometric dating of the igneous samples in the Barents Sea region. New 40Ar/39Ar dating of thirteen samples from Svalbard reveal ages of crystallization and alteration. The large age span (60–140 Ma for the raw ages) is likely due to partial or complete overprint of the K/Ar system in plagioclase, and the age of the magma emplacement is better represented by U/Pb TIMS ages. Only one of our 40Ar/39Ar analyses of plagioclase yielded a statistically valid age that is in line with the recently published U/Pb TIMS ages of 122–125 Ma. The new data clearly document that relying on published data from the K/Ar system can lead to erroneous conclusions on the age of crystallization in this province without a careful use of additional 40Ar/39Ar degassing data (i.e., K/Ca). We propose that the magmatism on Svalbard and Franz Josef Land represents a distinct magmatic event near the Barremian/Aptian boundary (125 Ma) in the Barents Sea. This Early Cretaceous Barents Sea magmatism resulted in the formation of the BSSC (Barents Sea Sill Complex). BSSC age rocks are also present in Arctic Canada (Sverdrup Basin) and on Bennett Island (New Siberia Islands). The massive injection of hot magma into potentially organic-rich sediments in the eastern and northern Barents Basin caused rapid organic matter maturation and formation of thermogenic gas and oil in contact aureoles. We estimate that up to 20,000 Gt of carbon were potentially mobilized, corresponding to 175 trillion barrels of oil equivalent. The production rates and fate of the carbon gases are uncertain. However, we speculate that rapid release of aureole greenhouse gases (methane) may have triggered the Oceanic Anoxic Event 1a (OAE1a) and the associated negative δ13C excursion in the Early Aptian. Some of the methane may also be trapped in the vast hydrocarbon gas accumulations found in the east Barents Basin.

The Inferred Aptian Cretaceous Paleoceanography of the South Atlantic

Late Aptian (Cretaceous) paleoceanography of the South Atlantic Ocean inferred from dinocyst communities of the Sergipe Basin

Authors:

Carvalho et al

Abstract:

The late Aptian (Early Cretaceous) is a crucial time interval for understanding the paleoceanographic changes in the Southern Hemisphere. Oceanographic changes in the emerging South Atlantic Ocean during this interval are reflected in the stratigraphic distribution of dinoflagellate communities recorded in the Muribeca and Riachuelo formations of the Sergipe Basin in northeastern Brazil. The Subtilisphaera community, in the lower and middle parts of the section, appears to be related to the Subtilisphaera Ecozone and suggests the onset of Tethyan influence in the central South Atlantic, in a restricted to inner-neritic environment. The succeeding Spiniferites community, in the middle part of the section, represents the first significant transgression, probably of eustatic origin. The Cyclonephelium-Exochosphaeridium community, in the upper part of the section, appears to be related to an oceanic event characterized by intermittent dysoxic-anoxic conditions. The uppermost part of the section is dominated by the Spiniferites community, related to a progressive regional transgression and culminating in an open-marine, fully Tethyan environment in the central part of the widening South Atlantic.

Evidence of Giant, Explosive Volcanic Eruptions During the Aptian Cretaceous

Aptian giant explosive volcanic eruptions in the Songliao Basin and northeast Asia: A possible cause for global climate change and OAE-1a

Authors:

Wang et al

Abstract:

Volcanism is a natural climate force that causes variations in temperatures. The Aptian Oceanic Anoxic Event 1a (OAE-1a) was preceded by a prominent negative C-isotope excursion attributed to major volcanism of the Ontong Java plateau (OJP), which presumably resulted in a pCO2 increase and a climatic change. However, the OJP alone may not adequately explain some important isotopic signatures such as the negative strontium-isotope excursion from 125 Ma to 113 Ma that is recorded in the corresponding marine deposits. We present an independent and hitherto undocumented case, the giant Aptian volcanism in the Songliao Basin and northeast Asia (SB-V) on the Cretaceous active continental margin between the Eurasian and the Pacific plates, which covered an area of ca. 2.3 × 106 km2, nearly matching the simultaneous case of the OJP. Intensive strong, explosive volcanic eruptions of the SB-V occurred at 121–109 Ma and introduced a large volume of fine-grained volcanic ash and degassing volatiles into the atmosphere. The Aptian isotopic ratios (87Sr/86Sr, 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb) of marine carbonates from the Mid-Pacific shift in values between their Barremian pre-excursion high values and the negative magmatic values of the SB-V. The transient global cooling at the onset of the OAE-1a coincided with the beginning of the violent acidic eruption of the SB-V (119.9–120.2 Ma). We therefore infer that the SB-V must have played a role in the Aptian global climatic changes and OAE-1a through the heavy fall of volcanic dust and the outgassing of aerosol and greenhouse gases.

A Conifer Woodland From Aptian/Albanian Cretaceous Patagonia

Aptian–Albian Cupressaceae (sensu stricto) woods from Cañadón Asfalto Basin, Patagonia Argentina

Authors:

Brea et al

Abstract:

This paper describes the first macrofloristic record from Los Adobes Formation (Chubut Group) in Cañadón Asfalto Basin (Patagonia, Chubut Province, Argentina). The studied fossils were recovered from the Aptian–Albian Bardas Coloradas Member, and consist of silicified woods preserved in fluvial channel deposits. One wood shows homocellular rays with smooth radial and tangential walls, diffuse axial parenchyma, tracheid pitting of the abietinoid type and cross-field pitting cupressoid usually ordered in rows and columns indicating placement within Cupressinoxylon hallei Kräusel. This fossil tree resembles some members of the extant Cupressaceae s.s., as Austrocedrus chilensis (D. Don) Pic. Serm. & Bizzarri, Pilgerodendron uviferum (D. Don) Florin, Fitzroya cupressoide (Molina) I. M. Johnst. and Libocedrus plumosa (D. Don) Druce. Due to poor preservation the other fossil wood specimen was assigned to cf. Cupressinoxylon Göppert 1850 nom. cons. prop. This is the first unequivocal record of C. hallei from the Cretaceous of South America and the oldest reliable record of the Callitroideae, indicating that this subfamily was well established since the mid-Cretaceous in the Southern Hemisphere.

Two new Species of Gobiconodon Mammals From Aptian/Albian Cretaceous China

Two new species of Gobiconodon (Mammalia, Eutriconodonta, Gobiconodontidae) from the Lower Cretaceous Shahai and Fuxin formations, northeastern China

Authors:

Kusuhashi et al

Abstract:

Two new gobiconodontid mammals, Gobiconodon tomidaisp. nov. and Gobiconodon haizhouensissp. nov., from the Lower Cretaceous (Aptian to Albian) Shahai and Fuxin Formations, respectively, in Liaoning Province, northeastern China, are described. Gobiconodon tomidaisp. nov. is a small-sized species of the genus characterised by the lower dental formula 2.1.2.5, a double-rooted p2, the molariform crown being mesiodistally longer than tall, and a distinct and almost continuous lingual cingulid on m2–m4. Gobiconodon haizhouensissp. nov. is of similar size to Gobiconodon tomidaisp. nov. and is characterised by the lower dental formula 2.1.3.5, the molariform crown being slightly taller than the mesiodistal length, and a well-developed and almost continuous lingual cingulid on m1–m3. The new materials indicate that the upper molariform count of most species of Gobiconodon is likely to be four, one less than the lower molariform count. Gobiconodon is the second mammalian genus common to the Jehol and Fuxin mammalian faunas.

What's in a Wing? Aptian Cretaceous Enantiornithine Bird Shows Perfect Flight Adaptation

Birds have an enormously long evolutionary history: The earliest of them, the famed Archaeopteryx, lived 150 million years ago in what is today southern Germany. However, whether these early birds were capable of flying -- and if so, how well -- has remained shrouded in scientific controversy. A new discovery published in the journal Scientific Reports documents the intricate arrangement of the muscles and ligaments that controlled the main feathers of the wing of an ancient bird, supporting the notion that at least some of the most ancient birds performed aerodynamic feats in a fashion similar to those of many living birds.

An international team of Spanish paleontologists and NHM's Director of the Dinosaur Institute, Dr. Luis M. Chiappe, studied the exceptionally preserved wing of a 125-million-year-old bird from central Spain. Beyond the bones preserved in the fossil, the tiny wing of this ancient bird reveals details of a complex network of muscles that in modern birds controls the fine adjustments of the wing's main feathers, allowing birds to master the sky.

"The anatomical match between the muscle network preserved in the fossil and those that characterize the wings of living birds strongly indicates that some of the earliest birds were capable of aerodynamic prowess like many present-day birds," said Chiappe, the investigation's senior scientist.

link.

open access paper link.

The Phylogenetics of 5 Mammals From Aptian/Albian Cretaceous Texas and Oklahoma

Taxonomic revision of tribosphenic mammals from the Lower Cretaceous Antlers Formation of Texas and Oklahoma, USA.

Author:

Averianov

Abstract:

There are five taxa of tribosphenic mammals in the Early Cretaceous Antlers Formation of Texas and Oklahoma, USA: a basal stem therian (Kermackia texana), stem therians near the eutherian-metatherian dichotomy (Holoclemensia texana and Pappotherium pattersoni), and stem marsupials (Atokatheridium boreni and Oklatheridium szalayi). K. texana has a primitive therian postcanine formula with three molars, replacement of p5, M3 with low protocone and no conules, lower molars with a large trigonid angle, oblique protocristid, paraconid smaller than metaconid (except m3), strong distal metacristid, narrow talonid, small talonid basin, and small entoconid (absent on m3). H. texana also has replacement in the fifth premolar locus and three molars. It is more derived in having a larger protoconal region with higher protocone and conules present, lack of distal metacristid, smaller trigonid angle, transverse protocristid, and wide talonid with larger talonid basin. It is similar to Eutheria by having M1 with reduced ectoflexus, semimolariform p5, and low trigonid angle with transverse protocristid. Holoclemensia cannot be referred to Eutheria because of the lack of the second rank postvallum/prevallid shear and unwinged conules. P. pattersoni (=Slaughteria eruptens) has replacement in the fifth premolar position, premolariform p5, and three molars (symplesiomorphies for Theria). It is more derived than Holoclemensia in having a wider and shorter talonid. Pappotherium is similar to Eutheria in having a low trigonid angle, transverse protocristid, and the cristid obliqua labial to the protocristid notch. It cannot be attributed to the Eutheria because of the narrow protoconal region, low protocone, small conules lacking internal cristae, postprotocrista not extending labially past the metacone base, and a small talonid basin. Atokatheridium boreni and Oklatheridium szalayi (=O. minax, syn. nov.) have four molars and emphasis on the postvallum/prevallid shear (large metacone on M2, strong postmetacrista, paraconid higher than metaconid). These taxa cannot be attributed to the Deltatheroida because of large protoconal region with winged conules. Oklatheridium is further different from the Deltatheroida in having a wider talonid and better developed entoconid.

Evidence of Wildfire From Aptian/Albian Cretaceous Brazil

Evidence of palaeo-wildfire from the upper Lower Cretaceous (Serra do Tucano Formation, Aptian–Albian) of Roraima (North Brazil)

Authors:

Scaramuzza dos Santos et al

Abstract:

Wood fossil charcoal is identified from the upper Lower Cretaceous (Serra do Tucano Formation, Aptian–Albian) of Roraima (North Brazil). The presence of charcoal demonstrates the occurrence of Early Cretaceous palaeo-wildfires for the first time in this region and only the third time for the entirety of South America. A gymnospermous taxonomic affinity can be established for the charred woods and a relationship with conifers is likely, thus providing additional evidence for the taxonomic composition of Early Cretaceous floras in this region.

Tetrapodophis amplectus: That Controversial Four Legged Snake From Aptian Cretaceous Brazil

A four-legged snake from the Early Cretaceous of Gondwana

Authors:

Martill et al

Abstract:

Snakes are a remarkably diverse and successful group today, but their evolutionary origins are obscure. The discovery of snakes with two legs has shed light on the transition from lizards to snakes, but no snake has been described with four limbs, and the ecology of early snakes is poorly known. We describe a four-limbed snake from the Early Cretaceous (Aptian) Crato Formation of Brazil. The snake has a serpentiform body plan with an elongate trunk, short tail, and large ventral scales suggesting characteristic serpentine locomotion, yet retains small prehensile limbs. Skull and body proportions as well as reduced neural spines indicate fossorial adaptation, suggesting that snakes evolved from burrowing rather than marine ancestors. Hooked teeth, an intramandibular joint, a flexible spine capable of constricting prey, and the presence of vertebrate remains in the guts indicate that this species preyed on vertebrates and that snakes made the transition to carnivory early in their history. The structure of the limbs suggests that they were adapted for grasping, either to seize prey or as claspers during mating. Together with a diverse fauna of basal snakes from the Cretaceous of South America, Africa, and India, this snake suggests that crown Serpentes originated in Gondwana.