Basal Member Research Articles

Anatomically preserved Silurian ‘nematophytes’ from the Welsh Borderland (UK)

Stratified charcoalified fragments of thalloid organisms with tripartite tissue construction have been isolated from the basal member of the Upper Silurian (upper Ludlow) Downton Castle Sandstone Formation, exposed near Ludlow, Shropshire (England) and are considered to have had fungal affinity. They are divided into two major groups. The more novel of these is characterized by a superficial cortex separated from a basal layer of interweaving hyphae by an intermediate zone of compressed indeterminate tissue and members are placed in a new taxon, Tristratothallus ludfordensis. In the second, the intermediate zone comprises hyphae arranged at right angles to the cortex (termed palisade). Some members resemble the tissue construction of Nematothallus described from the Lower Devonian (Lochkovian) of the Welsh Borderland and considered to belong to fungi, some of which were lichenized. A further type, which shows remains of polysporic asci, is thought to represent a fragment of an apothecium (a disc-shaped ascoma of an ascomycete) of a pezizomycete and is the earliest such record. Yet others are characterized by a perforate cortex with occasional protruding hyphae, tissue construction of which was also recorded in the Lower Devonian of the Welsh Borderland and considered to display fungal characteristics. Coalified ‘black patches’ are common on bedding surfaces throughout the latest Silurian and Early Devonian and frequently are associated with basal embryophytes and tracheophytes. Those reported here are the oldest known with three-dimensional organization, studied via scanning electron microscopy (SEM) and attributed to fungi, and include some ascomycetes. Similar encrustations occur in even earlier rocks and may have been important constituents of the cryptogamic ground cover, which is postulated to have preceded higher plant life on land.

An Early Jurassic braided river system from Mehadia, South Carpathians, Romania

The Lower Jurassic (Hettangian–Sinemurian) continental deposits of the Mehadia area (Caras–Severin County) belong to the Presacina Basin, Upper Danubian Units of the South Carpathians, Romania. This un-named succession is exposed along large areas within the Greaţca Quarry where deposits of a complex braided river system can be seen. Nine clastic facies are identified within the Mehadia section and grouped into two facies associations reflecting two main sub-environments. (A) a fine-grained association, up to 6.5 m thick, composed of greyish black and dark grey massive and horizontally laminated mudstones interbedded with fine- to medium-grained sandstones showing ripple lamination, tabular low-angle large-scale cross-bedding and in some places massive sandstones. Within this association coarsening and fining-upward sequences are visible, while subordinate pensymmetrical-like sequences were observed. The sediments of the fine-grained association are interpreted as having been deposited along an alluvial plain from flood waters. The sandstone interbeds are interpreted as crevasse channel-fills and the thinner sandstone bodies as proximal crevasse splays. (B) a coarse-grained facies association represented by sandstones and conglomerates, both clast- and matrix-supported, from granule to pebble clast sizes. Almost all basal members of this association are underlain by erosional surfaces, while internal erosional surfaces occur at some levels. The coarse-grained facies association is interpreted as having been deposited within active river channels of a sandy braided river system. The occurrence of numerous erosional surfaces, the recurrence of the facies within this association (channel bodies), as well as the abundant mudstone and sandstone intraclasts all point to frequent conditions of erosion (including redeposition) of previously deposited sediments. The relatively low fine-grained sediment content (<25%) can be explained by two factors: (1) a creation rate for accommodation space was not enough for the accumulation of a large amount of overbank deposits; (2) a lack of larger quantities of fine-grained material being transported in the river system. Both factors may have operated independently or interacted.

Age of Jurassic basal sauropods in Sichuan, China: A reappraisal of basal sauropod evolution

Sauropoda are the largest terrestrial animals to have ever lived and represent the dominant herbivorous dinosaurs of the Mesozoic Era. The Lower Shaximiao Formation of the Sichuan Basin, Southwest China, hosts abundant Jurassic basal sauropods including the Shunosaurus-Omeisaurus Fauna. This formation was previously hypothesized to be Middle Jurassic based on biostratigraphic interpretations, but the exact depositional age is uncertain. Here we report the youngest inductively coupled plasma-mass spectrometry (ICP-MS) detrital zircon U-Pb age of 159 +/- 2 Ma for fossil-bearing strata from this formation as the maximum depositional age. This age falls very close to the Oxfordian age interpreted for the Shunosaurus-Omeisaurus Fauna and is younger than previously proposed. We suggest that when the widely distributed basal sauropods of the Early-Middle Jurassic were mostly replaced by the phylogenetically more-derived neosauropods in the Late Jurassic in other regions of Laurasia and Gondwana, some more basal members survived and diversified in the Sichuan Basin of southwestern China.

The Niobrara formation in the Southern Powder river basin, Wyoming: An emerging giant continuous petroleum accumulation

The Niobrara Total Petroleum System (TPS) covers an extensive area across the Rocky Mountain Region, US. In the Powder River Basin (PRB), the petroleum system consists of source beds in the Upper Cretaceous Niobrara Formation as well as reservoirs in the Upper Cretaceous Frontier, Turner, Niobrara, Sussex, Shannon, Parkman, Teapot, and Teckla. The Niobrara is a deep-water hemipelagic carbonate mudrock and is Coniacian to early Campanian in age and approximately 150-650 ft thick. The formation, where productive, has low porosity (< 10%), low permeability (<0.01 md), and pore throat sizes less than 0.1 micron. The immature-mature present-day depth boundary is approximately 8000 ft. The formation is subdivided informally into three units in the PRB (A, B, and C). The units consist of cycles of marls and chalks. Geologic factors related to successful exploration and development include excellent source-rock quality, source-rock maturity, reservoir thickness, matrix and fracture porosity and permeability development, high geothermal gradients, overpressure, oil gravity, gas-oil ratios, and regional fracture development. The accumulation covers a large area and is a potential giant accumulation. Recent drilling success by several operators indicates that productive reservoir conditions exist in the southern PRB (Figure 1). In this area, the Niobrara Formation consists of three marly chalk facies, informally referred to in descending order as A, B, and C benches that are separated by marls, similar to the Denver Basin (Figure 2). The basal Fort Hays Member of the Niobrara Formation is absent in the southern PRB (Weimer and Flexer, 1985; Taylor, 2012). The main reservoir target currently in the southern PRB is the Niobrara B chalk/marl interval. Porosities are 6-12% and permeabilities are less than 0.01 mD (Taylor, 2012). Hydrocarbons are generated from mainly a marine type II kerogen with total organic carbon content (TOC) averaging 2-3 wt.% for the interstratified organic-rich source beds (Anna, 2009).

Evolution through cold and deep waters: the molecular phylogeny of the Lithodidae (Crustacea: Decapoda)

The objectives of this work are to use gene sequence data to assess the hypothesis that the Lithodinae arose from ancestors with uncalcified abdomens in shallow waters of the North-East Pacific, investigate the monophyly and interrelationships of genera within the Lithodinae and to estimate the scale and minimum number of biogeographic transitions from the shallow environment to the deep sea and vice versa. To do this, phylogenetic analysis from three mitochondrial and three nuclear markers was conducted using minimum evolution, maximum likelihood and Bayesian methods. The Lithodinae as defined to include North Pacific genus Cryptolithodes may be paraphyletic, with the Hapalogastrinae and Cryptolithodes as sister taxa. This implies that the soft-bodied abdomen of the Hapalogastrinae might not be plesiomorphic for the Lithodidae. Paralomis, Lopholithodes, Phyllolithodes, Lithodes and Neolithodes share a common ancestor, from which the North Pacific Hapalogastrinae did not descend. Lithodid ancestors are likely to have had a north Pacific, shallow water distribution and to have had planktotrophic larvae. North Pacific genus Paralithodes is paraphyletic; P. brevipes is the most basal member of the genus (as sampled) while P. camtschaticus and P. platypus are more closely related to the genera Lithodes and Neolithodes. Genera Lithodes, Neolithodes and Paralomis (as sampled) are monophyletic if Glyptolithodes is included within Paralomis. Lopholithodes is closely related to, but not included within, the Paralomis genus. Paralomis is divided into at least two major lineages: one containing South Atlantic, West African, and Indian Ocean species, and the other containing Pacific and South American species. Several species of Paralomis do not resolve consistently with any other groups sampled, implying a complex and possibly rapid global evolution early in the history of the genus. Relationships within the Lithodes genus vary between analytical methods, suggesting that conclusions may not be stable. Consistently, however, Indian Ocean and Pacific forms—L. murrayi, L. longispina and L. nintokuae form a group separated from Atlantic species such as L. santolla, L. confundens, L. maja and L. ferox.

A mosasaur fauna (Squamata: Mosasauridae) from the Campanian (Upper Cretaceous) of Hannover, northern Germany

Hornung, J.J., Reich, M. & Frerichs, U., February 2018. The mosasaur fauna (Squamata: Mosasauridae) from the Campanian (Upper Cretaceous) of Hannover, northern Germany. Alcheringa 42, 543-559. ISSN 0311-5518. Isolated teeth and a humerus from the Campanian of Hannover indicate a considerable local diversity of mosasaur taxa. The lower Misburg Formation (lower Campanian of the Lehrte West Syncline) yields Clidastes sp. (Mosasaurinae), Prognathodon sp. (Mosasaurinae), ?Hainosaurus sp. (Tylosaurinae) and an unidentified mosasaurid. It further confirms the presence of the genus Clidastes in northern central Europe and also proves the early Transatlantic distribution of a basal member of Prognathodon during the lower Campanian. ?Hainosaurus sp. is similar to roughly contemporaneous material of Hainosaurus sp. from southern Sweden. The upper Misburg Formation (upper upper Campanian) shows a different taxonomic composition with Tylosaurus sp. (Tylosaurinae), a second indeterminate species of Prognathodon and ?Platecarpus sp. The limited material of Prognathodon sp. shows closest affinities to P. lutugini (Yakovlev) from eastern Europe. The records of Tylosaurus and ?Platecarpus are among the stratigraphically youngest of these taxa. Facies and lithology of the Misburg Formation indicate that the mosasaurs lived in an open marine, mid-sublittoral environment with a water-depth around 70–100 m. In the contemporaneous chalk facies, deposited in somewhat deeper waters, as well as in shallow littoral deposits, mosasaurs are very rare and of lower diversity. Jahn J. Hornung [ jahn.hornung@yahoo.de ] Landesmuseum Hannover, Willy-Brandt-Allee 5, 30169 Hannover, Germany; Current address: Fuhlsbüttler Strasse 611, 22337 Hamburg, Germany; Mike Reich [ mreich@lrz.uni-muenchen.de & mike.reich@lmu.de ] SNSB—Bavarian State Collection of Palaeontology and Geology & Ludwig-Maximilian-Universität München, Department of Earth and Environmental Sciences, Section Palaeontology and Geobiology & GeoBio-Center LMU ; all: Richard-Wagner-Str. 10, 80333 Munich, Germany; Udo Frerichs [ udofrerichs@web.de ] Arbeitskreis Paläontologie Hannover, Buchenweg 7, 30855 Langenhagen, Germany

Malassezia vespertilionis sp. nov.: a new cold-tolerant species of yeast isolated from bats.

Malassezia is a genus of medically-important, lipid-dependent yeasts that live on the skin of warm-blooded animals. The 17 described species have been documented primarily on humans and domestic animals, but few studies have examined Malassezia species associated with more diverse host groups such as wildlife. While investigating the skin mycobiota of healthy bats, we isolated a Malassezia sp. that exhibited only up to 92% identity with other known species in the genus for the portion of the DNA sequence of the internal transcribed spacer region that could be confidently aligned. The Malassezia sp. was cultured from the skin of nine species of bats in the subfamily Myotinae; isolates originated from bats sampled in both the eastern and western United States. Physiological features and molecular characterisation at seven additional loci (D1/D2 region of 26S rDNA, 18S rDNA, chitin synthase, second largest subunit of RNA polymerase II, β-tubulin, translation elongation factor EF-1α, and minichromosome maintenance complex component 7) indicated that all of the bat Malassezia isolates likely represented a single species distinct from other named taxa. Of particular note was the ability of the Malassezia sp. to grow over a broad range of temperatures (7-40 °C), with optimal growth occurring at 24 °C. These thermal growth ranges, unique among the described Malassezia, may be an adaptation by the fungus to survive on bats during both the host's hibernation and active seasons. The combination of genetic and physiological differences provided compelling evidence that this lipid-dependent yeast represents a novel species described herein as Malassezia vespertilionis sp. nov. Whole genome sequencing placed the new species as a basal member of the clade containing the species M. furfur, M. japonica, M. obtusa, and M. yamatoensis. The genetic and physiological uniqueness of Malassezia vespertilionis among its closest relatives may make it important in future research to better understand the evolution, life history, and pathogenicity of the Malassezia yeasts.

Proteomic and functional variation within black snake venoms (Elapidae: Pseudechis)

Pseudechis (black snakes) is an Australasian elapid snake genus that inhabits much of mainland Australia, with two representatives confined to Papua New Guinea. The present study is the first to analyse the venom of all 9 described Pseudechis species (plus one undescribed species) to investigate the evolution of venom composition and functional activity. Proteomic results demonstrated that the typical Pseudechis venom profile is dominated by phospholipase A2 toxins. Strong cytotoxicity was the dominant function for most species. P. porphyriacus, the most basal member of the genus, also exhibited the most divergent venom composition, being the only species with appreciable amounts of procoagulant toxins. The relatively high presence of factor Xa recovered in P. porphyriacus venom may be related to a predominantly amphibian diet. Results of this study provide important insights to guide future ecological and toxinological investigations.

Towards a robust systematic baseline of Neotropical fish tapeworms (Cestoda: Proteocephalidae): amended diagnoses of two genera from the redtail catfish, Phractocephalus hemioliopterus.

Species of two monotypic genera, Ephedrocephalus Diesing, 1850 and Zygobothrium Diesing, 1850 (Cestoda: Proteocephalidae), parasites of one of the most basal members of the catfish family Pimelodidae, the redtail catfish, Phractocephalus hemioliopterus, in the Neotropical Region, are redescribed based on the evaluation of type specimens and newly collected material. Generic diagnoses are amended to provide a robust baseline for the future re-arrangement of the classification of proteocephalid cestodes. Ephedrocephalus is typified by the medullary position of the ovary and uterus, the cortical distribution of vitelline follicles (dispersed throughout almost the entire ventral cortex) and the testes in one dorsal field. Zygobothrium is primarily characterized by its possession of a robust scolex bearing four uniloculate suckers with two openings each and by the tetralobed velum (laciniations) on every proglottid (two on the ventral and two on the dorsal side). The redtail catfish is the definitive host of as many as seven species of proteocephalid cestodes, which, however, do not represent a monophyletic group. Some species, including Z. megacephalum, are among the earliest diverged parasites of Neotropical catfishes, being closely related to African and North American proteocephalids from catfishes, whereas others such as E. microcephalus belong to more recently diverged taxa with uncertain interrelations. Unlike most proteocephalids of the redtail catfish, which almost always infect the anterior parts of the host intestine, E. microcephalus and Z. megacephalum occur exclusively in its posterior third. A key to the identification of the proteocephalid species parasitizing P. hemioliopterus is also presented.

Cerinichthys koelblae, gen. et sp. nov., from the Upper Jurassic of Cerin, France, and its phylogenetic setting, leading to a reassessment of the phylogenetic relationships of Halecomorphi (Actinopterygii)

ABSTRACTUnknown, well-preserved fish specimens from the Upper Jurassic Plattenkalk of Cerin, France, found in the historical collection in Muséum d'Histoire Naturelle de Lyon, France, and from the excavation site of the Collections de Géologie, Université Claude Bernard Lyon 1, France, permit description of Cerinichthys koelblae, gen. et sp. nov. This new genus differs from all other Halecomorphi in the following combination of features: 27 caudal principal rays; 51 vertical scale rows; presence of broadened basal fin segments in the posterior rays of the pectoral, pelvic, anal, and dorsal fins and the median rays of the caudal fin; complete absence of vertebral centra in adult-sized individuals and multiple small scales in the median and ventral parts of the caudal peduncle. Investigations concerning the phylogenetic setting of the new genus Cerinichthys led to a proposal for a revision of the Halecomorphi, with Cerinichthys as a basal member of the new order Ophiopsiformes. The new family Ophiopsiellidae, as replacement for Ophiopsidae, within the Ophiopsiformes, are ganoin-scaled Halecomorphi with one horizontally elongated dorsal fin or two dorsal fins. The Ionoscopidae are proposed to belong in the Amiiformes, and the order Ionoscopiformes needs to be reconsidered. The more basal Halecomorphi with massive ganoin scales remain poorly known, compared with the more advanced halecomorph group of the Amiidae. Closer investigation of their morphology and taxonomic relationships is therefore important for understanding broader patterns of halecomorph evolution.http://zoobank.org/urn:lsid:zoobank.org:pub:0D13F672-DBC1-4484-AE30-7D360DCD3123SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVPCitation for this article: Ebert, M. 2018. Cerinichthys koelblae, gen. et sp. nov., from the Upper Jurassic of Cerin, France, and its phylogenetic setting, leading to a reassessment of the phylogenetic relationships of Halecomorphi (Actinopterygii). Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2017.1420071.

Nummulitids, lepidocyclinids and Sr-isotope data from the Oligocene of Kutch (western India) with chronostratigraphic and paleobiogeographic evaluations

Due to its intermediate geographical position between the Mediterranean and W Pacific, the Oligocene shallow-marine sequence of Kutch (India) is of key importance in paleobiogeographical interpretations. Larger benthic foraminifera (LBF) are a fundamental link for the correlation between the Mediterranean shallow benthic zones (SBZ) and the W Pacific ‘letter stages’. LBF were re-evaluated by morphometric studies of the internal test from five stratigraphic sections of the Maniyara Fort Formation. Based on their significant affinity to coeval fauna in the Mediterranean, they were assigned to W Tethyan SBZ zones, supported by Sr-isotope stratigraphy. In the Basal Member, traditionally considered as early Rupelian, we identified Nummulites bormidiensis, N. kecskemetii and Heterostegina assilinoides assigning it to the early Chattian SBZ 22B Zone. The Coral Limestone Member, previously considered as late Rupelian, is also assigned to this zone, for the presence of N. bormidiensis, Eulepidina formosoides-dilatata and Nephrolepidina morgani-praemarginata. Its early Chattian age (26.5–29 Ma) is further supported by Sr-isotope data. Miogypsinoides complanatus and Spiroclypeus margaritatus in the Bermoti Member (the top of the formation) document the late Chattian SBZ 23 Zone and the Sr-isotope data (22.5–24 Ma) place it close to the Oligocene–Miocene boundary.

The oldest titanosaurian sauropod of the Northern Hemisphere

Volgatitan simbirskiensis, gen. et sp. nov., is described based on a series of anterior and middle caudal vertebrae from a single individual discovered in the Lower Cretaceous (upper Hauterivian, Speetoniceras versicolor ammonite Zone) marine deposits at Slantsevy Rudnik vertebrate locality near Ulyanovsk City, Russia. The new taxon is characterized by strongly procoelous anterior and middle caudal vertebrae, a long centrum of the first caudal vertebra, a strong ventral ridge in the anterior and middle caudal vertebrae, a neural arch positioned at the anterior half of the centrum, hyposphene-hypantrum articulation in the anterior caudal vertebrae, and somphospondylous bone texture. Phylogenetic analysis places the new taxon as a lithostrotian titanosaur, a basal member of the lineage leading to the Lognkosauria. This lineage previously contained only South American taxa with body mass reaching 60–70 tons. Volgatitan gen. nov. is the first European and the geologically oldest representative of this lineage. Its body mass is estimated as 17.3 tons. Discovery of Volgatitan gen. nov. suggests that the lithostrotian lineage leading to the Lognkosauria had a wider distribution in the Early Cretaceous and became extinct everywhere except South America by the end of the Early Cretaceous.

Timing of volcanism and initiation of rifting in the Omo-Turkana depression, southwest Ethiopia: Evidence from paleomagnetism

Lava flows of the Gombe Group basalt cover the base of the Omo-Turkana rift in southwestern Ethiopia and northern Kenya. Paleomagnetic study results on these basalts are integrated with previous geochronologic data to better constrain the timing of volcanism and rifting in the area. A total of 80 drilled core samples were collected from nine sites. Experimental methods of Alternating Field (AF) demagnetization, Thermal (TH) demagnetization and Isothermal Remanent Magnetization (IRM) experiments are performed to unravel components of magnetizations. Two components of Natural Remnant Magnetization (NRM) directions are identified; the first one considered as Viscous Remanent Magnetization (VRM) is removed by 5–25 mT AF or a temperature of 120 °C–250 °C, the second component isolated after these steps defined a straight-line segment directed towards the origin and is interpreted as the Characteristic Remanent Magnetization (ChRM). In the IRM Acquisition experiment all analyzed samples showed a sharp rise in acquisition and reached to their saturation magnetization by an applied field of 300 mT. This together with the AF demagnetization and TH demagnetization behaviors suggest pseudo single domain titanomagnetite as a dominant magnetic carrier of the remanence. From a total of nine sites, six sites are reversed polarity, two sites are normal polarity and pass the reversal test of McFadden and McElhinny (1990) while one site is of erratic behavior probably due to lightning strike. The mean direction for the reversed polarity is DS = 186.1°, IS = −1.9° (N = 2, KS = 38.8, α95 = 10.9°) and that for the normal polarity is DS = 348.4°, IS = 4.6° (N = 6, K = 378.9, α95 = 12.9°). The overall mean direction DS = 1.7°, IS = 2.6° (N = 8, KS = 34.2, α95 = 9.6°), is statistically identical to the expected mean direction Ds = 2.1°, Is = 7.8° (N = 26, α95 = 2.3) obtained from the African Apparent Polar Waner Path (APWP) curve of African plate for a mean age of 4.25 Ma (Besse and Courtillot, 1991, 2003). Considering the upper age control of Moiti tuff (3.98 Ma) and Naibar tuff (4.02 Ma) which have not been intruded by the Gombe Group basalts; with the obtained paleomagnetic result the Gombe Group basalts are correlable with the late Gilbert Chron of Cande and Kent (1995) specifically at and just above the Cochiti normal sub-Chron (4.18 Ma–4.29 Ma) consistent with paleomagnetic study from the basal members of the Shungura Formation (Kidane et al., 2014). Petrographically and geochemically similar basalts (Haileab et al., 2004) in northern Kenya are reported to have the same polarity. This suggests the longitudinally distributed lava flows (Gombe Group) in Northern Kenya and southwestern Ethiopia probably had erupted in a short period between 4.18 Ma–4.29 Ma. This similarity indicates that the present architecture of the basin might have been attained soon after the emplacement of the Gombe Group basalt.

Pliocene–Pleistocene palaeoclimate reconstruction from Ashalim Cave speleothems, Negev Desert, Israel

Abstract Speleothems from Ashalim Cave, located in the arid central Negev Desert, Israel, were used in a reconstruction of the palaeoclimate of the northern Saharan–Arabian desert margin. The sequence of speleothems is composed of three stratigraphic members: the yellow Pliocene Basal Member, the brown Early Pleistocene Intermediate Member and the thin Middle–Late Pleistocene Young Member. The age of the Basal Member is c. 3.1 Ma and the base of the Intermediate Member is 1.272 ± 0.018 Ma. Two last deposition periods of the Young Member occurred at 221–190 ka (Negev Humid Period (NHP) 2) and 134–114 ka (NHP-1), associated with interglacial marine isotopic stages 7.3–7.1 and 5.5, respectively. NHP-1 and -2 occurred when the African monsoon index was highest in the last 221 ka. The δ 18 O values of the speleothems range between −6.9 and −11.2‰, 2–4‰ less than in the speleothems of central and northern Israel. This may indicate a remote southern tropical source of precipitation, although during NHP-1 and -2 the thickness of the Negev Desert speleothems decreases from north to south, showing a stronger northern Mediterranean source of moisture. The δ 13 C values of the speleothems (3.5 to −8.5‰) show steppe to semi-desert C4 type vegetation. The 87 Sr/ 86 Sr ratios of the speleothems increased from c. 0.7078 in the Pliocene to 0.7082–0.7085 in the Pleistocene, indicating an increasing supply of desert dust and a decrease in host rock weathering.

The tetrapod fauna of the upper Permian Naobaogou Formation of China: 1. Shiguaignathus wangi gen. et sp. nov., the first akidnognathid therocephalian from China.

The Permian from China has a well-known terrestrial record where approximately 30 tetrapod taxa, including several therapsids, have been described. However, the record of therocephalians in China has remained elusive. Shiguaignathus wangi gen. et sp. nov., discovered in the Member III of the Naobaogou Formation, Nei Mongol, China, is here described. This is the first therocephalian recovered from this fauna and only the second from the Permian of China. It is represented by a well-preserved robust snout of a medium-sized animal. This is the first akidnognathid reported from the Chinese Permian and only the second genus from Laurasia as one genus is known from Russia whereas the remaining members of the group are from the South African Karoo Basin. A phylogenetic analysis of therocephalians supports a basal position of S. wangi within Akidnognathidae, followed by the Russian Annatherapsidus. Akidnognathidae is the latest major group of therocephalian appearing in the fossil record, and one of the few that does not have species from South Africa representing its most basal members.

Masticatory jaw movement of Exaeretodon argentinus (Therapsida: Cynodontia) inferred from its dental microwear

Dental microwear of four postcanine teeth of Exaeretodon argentinus was analyzed using both two dimensional (2D) and three dimensional (3D) methods to infer their masticatory jaw movements. Results of both methods were congruent, showing that linear microwear features (scratches) were well aligned and mostly directed to the antero-posterior direction in all four teeth examined. These findings support the palinal masticatory jaw movement, which was inferred in previous studies based on the observation of gross morphology of wear facets. In contrast, the lack of detection of lateral scratches confirmed the absence of the lateral jaw movement that was also proposed by a previous study. Considering previous microwear studies on cynodonts, palinal jaw movements observed in Exaeretodon evolved within cynognathian cynodonts from the fully orthal jaw movement of its basal member. Although there are currently only three studies of dental microwear of non-mammalian cynodonts including the present study, microwear analysis is a useful tool for the reconstruction of masticatory jaw movement and its future application to various cynodonts will shed light on the evolutionary process of jaw movement towards the mammalian condition in more detail.

Phylogenomics of Bartheletia paradoxa reveals its basal position in Agaricomycotina and that the early evolutionary history of basidiomycetes was rapid and probably not strictly bifurcating

The higher level phylogeny of fungi has been addressed in previous studies, but for those analyses, either taxon sampling or gene sampling was low, or some basal lineages important for the inference of basidiomycete phylogeny were lacking. Here, a phylogenomic analysis based on highly conserved genes and including the enigmatic species Bartheletia paradoxa from Ginkgo biloba is presented. While phylogenetic analyses including also less conserved parts of core eukaryotic genes yielded a basal position for the extremophile genus Wallemia with low support, an exclusion of highly variable parts of these genes suggested Bartheletia paradoxa as the most basal member of the Agaricomycotina, but again with low support. Network analyses suggest a network-like evolution at the base of the Basidiomycota, supported by phylogenies based on single genes and gene clusters with shared topology. When further removing noise by removing poorly resolving genes, strong but not maximum support was obtained for Bartheletia paradoxa being the sister lineage to all other Agaricomycotina. We speculate that the lack of support for the early splits in Agaricomycotina and Basidiomycota can probably be explained by rapid radiation, linked to major evolutionary developments, such as, in the case of Basidiomycota, the advent of basidia in the last common ancestor.

Late Australopiths and the Emergence of Homo

New fossil discoveries and new analyses increasingly blur the lines between Australopithecus and Homo, changing scientific ideas about the transition between the two genera. The concept of the genus itself remains an unsettled issue, though recent fossil discoveries and theoretical advances, alongside developments in phylogenetic reconstruction and hypothesis testing, are helping us approach a resolution. A review of the latest discoveries and research reveals that (a) despite the recent recovery of key fossil specimens, the antiquity of the genus Homo remains uncertain; (b) although there exist several australopith candidate ancestors for the genus Homo, there is little consensus about which of these, if any, represents the actual ancestor; and (c) potential convergent evolution (homoplasy) in adaptively significant features in late australopiths and basal members of the Homo clade, combined with probable reticulate evolution, makes it currently impossible to identify the direct ancestor of Homo erectus.

Possible hominin footprints from the late Miocene (c. 5.7 Ma) of Crete?

We describe late Miocene tetrapod footprints (tracks) from the Trachilos locality in western Crete (Greece), which show hominin-like characteristics. They occur in an emergent horizon within an otherwise marginal marine succession of Messinian age (latest Miocene), dated to approximately 5.7 Ma (million years), just prior to the Messinian Salinity Crisis. The tracks indicate that the trackmaker lacked claws, and was bipedal, plantigrade, pentadactyl and strongly entaxonic. The impression of the large and non-divergent first digit (hallux) has a narrow neck and bulbous asymmetrical distal pad. The lateral digit impressions become progressively smaller so that the digital region as a whole is strongly asymmetrical. A large, rounded ball impression is associated with the hallux. Morphometric analysis shows the footprints to have outlines that are distinct from modern non-hominin primates and resemble those of hominins. The interpretation of these footprints is potentially controversial. The print morphology suggests that the trackmaker was a basal member of the clade Hominini, but as Crete is some distance outside the known geographical range of pre-Pleistocene hominins we must also entertain the possibility that they represent a hitherto unknown late Miocene primate that convergently evolved human-like foot anatomy.

After the disaster: Bony fish remains (mostly otoliths) from the K/Pg boundary section at Stevns Klint, Denmark, reveal consistency with teleost faunas from later Danian and Selandian strata.

This is the first study of bony fish remains across the K/Pg boundary section at Stevns Klint, Denmark. The studied specimens comprise one partly preserved articulated skeleton, a few isolated bones, and casts from several otolith imprints and voids. As otoliths are aragonitic, the remains are all dissolved. The imprints of the otoliths originate from the uppermost Maastrichtian Højerup Member or ‘Grey Chalk’, and the bone fragments and the partial skeleton were obtained from the Fiskeler Member directly above the K/Pg boundary. Further otolith imprints originated from the basal Danian Cerithium Limestone Member, which directly overlies the Fiskeler Member. Six otolith-based taxa were identified from the uppermost Maastrichtian and three from the basal Danian. One of the species found in the uppermost Maastrichtian persisted into Danian times (Polymixia? harderi), a second represents a common genus in both Maastrichtian and Danian but cannot be identified to the species level (Centroberyx sp.), and a third taxon is an unidentifiable dynematichthyid, which, however, certainly does not belong to any of the known Danian dinematichthyid species. The species recognised in the basal Danian all persisted well into later Danian times or even the Selandian, showing a remarkable consistency of the early Paleocene bony fish fauna. We find no indication of phased extinction in the aftermath of the K/Pg boundary event in the data recovered from the Danian.