Despite their relative abundance, members of the family Hypertragulidae (Artiodactyla, Mammalia) have proved a conundrum regarding species diversity in the Turtle Cove Member (Oligocene) of the John Day Formation, located in central and eastern Oregon. Three species and two separate genera are described in the area, but previous research lacks statistical support for this level of variation. We use coefficients of variation (V) on measurements of dentition and astragali of hypertragulid specimens designated Hypertragulus hesperius, Hypertragulus minutus, and Nanotragulus planiceps as a metric for determining whether there were multiple species present in the population. Asymptotic and modified signed-likelihood ratio V equality tests show that V values of anterior-posterior molar length and transverse molar width vary significantly when comparing single species of modern ecological analogs (Muntiacus muntjak, Muntiacus reevesi, and Tragulus javanicus) to groupings of a combined population. However, the V equality tests on dental and postcranial measurements yield almost no significant results when comparing variation in the extinct John Day hypertragulids to an extant population comprised of a single species. Similar comparisons between astragali measurements of hypertragulids and T. javanicus express no significant difference in the level of variation from the combined population to a modern single species. The low level of variation in the hypertragulids and the lack of differentiation between dental characters of individuals does not statistically support the hypothesis that there were multiple species present in the population, suggesting either that cryptic species may be present but impossible to identify without soft tissue remains, or there may have been taxonomic over-splitting of a single hypertragulid species in the John Day region.

The family Simoceratidae Spath, 1925, lumps various formsbelonging to lineages with different roots and is clearlyparaphyletic.One of its genera is Lytogyroceras Spath, 1924,which stands apart from the typical forms of the familybearing strong ribbing and tubercles.The sexual dimorphismof Lytogyroceras was supposed to be based only onadult size differences.Here we describe a recently collectedlappeted microconch of Lytogyroceras subbeticum (Olriz,1978) from the Ponti Zone of Carchelejo (southern Spain).This microconch shows that the sexual dimorphism in thegenus Lytogyroceras is not only characterized by differentadult size of the sexes as formerly assumed, but also by differentadult peristome morphology.

We describe a new genus of Leliacladus Batista & L.Kunzmann with the type species Leliacladus (Brachyphyllum

We describe two new genera of phymaraphiniid lithistid sponges Twertupia gen. nov. and Pickettispongia gen. nov. from the upper Eocene Pallinup Formation of South Western (SW) Australia based on new, rich and very well preserved material. Type material of these two genera, earlier described from poorly preserved material, were originally attributed to Thamnospongia subglabra and Stachyspongia neoclavatela (in case of species of Twertupia), and to Discoderma tabelliformis (case of species of Pickettispongia). This is the first record of bodily preserved phymaraphiniid sponges from Eocene rocks, as well as from the southern hemisphere. We discuss extant and fossil representatives of Phymaraphiniidae and their geographical distribution, concluding that the present day occurrences of these sponges are the result of a much larger Mesozoic Tethyan distribution.

High-spired Murchisonia-like slit-band gastropods are an important component of late Paleozoic gastropod faunas. Twenty-seven genera of such gastropods have been reported from the Permian, most of which representing the caenogastropod family Goniasmatidae. Only four genera, Trypanocochlea, Wannerispira, Laschmaspira, and Altadema crossed the Permian/Triassic boundary. Based on the study of newly collected specimens and material from natural history collections, we studied the surviving genera as well as the Triassic recovery of this group. Two new species (Laschmaspira lirata sp. nov. and Altadema hausmannae sp. nov.) and one new subfamily (Cheilotomoninae) are introduced. Murchisonia-like caenogastropods, chiefly Goniasmatidae, were diverse and abundant until the Permian, barely survived the end-Permian extinction, regained a certain generic diversity within the Triassic with the evolution of several new genera but failed by far to regain their Permian generic diversity. This once successful and diverse group shares a similar fate (surviving the end-Permian extinction, a reduced Triassic diversity and extinction during Late Triassic crises) as conodonts, orthoceratids, conulariids, and others. This diversity pattern does not qualify for the "Dead Clade Walking" phenomenon, i.e., the extinction shortly after a major mass extinction event (survival without recovery) because they have survived for ca. 30 Ma (at least until the Norian) and even produced a number of new genera. The exact time of their extinction is unknown but there are no safe Rhaetian occurrences. Their extinction is part of a long-term selective trend against the character "shell-slit".

Floian, Early Ordovician trilobites are systematically described and revised based on new material from the middle part of the Duoquanshan Formation of the Shihuigou area, northern Qinghai Province, northwest China. The fauna that lived on the shallow-water carbonate platform comprises three species belonging to two families, i.e., Tsaidamaspis diarmatus, Zhiyia tsinghaiensis, and Liexiaspis sp. indeterminate. It exhibits a strong endemicity to the Olongbluk terrane. The new isoteline genus Zhiyia is established on the basis of the material from the Olongbluk terrane and South China palaeoplate, and is characterized by its: (i) almost obsolete cephalic and pygidial axial furrows; (ii) flattened anterior border and narrow (sag., exsag.) occipital ring; (iii) bilobed hypostome with a shallow median notch and a small triangular median projection; (iv) subsemicircular pygidium with wide pygidial axis and border. Faunal evidence indicates that the palaeogeographic position of the Olongbluk terrane may have been situated closer to the South China palaeoplate rather than the North China palaeoplate during the Floian.

Well-preserved fossil assemblages provide valuable insights into the evolutionary history of biota and their environments. Here, we report on Rupelian (early Oligocene) siliceous nanoeukaryotes from diatomites in the Carpathian Mountains, southeastern Poland. These sediments yielded novel forms of parmaleans and parmalean-like fossils. Their cell wall structure differs from that of described genera. Instead of the generically specific separate dorsal plate and set of girdle plates, some of our taxa contain one upended, hollow, subspherical, perforated cup. To accommodate these differences, we propose a new division Parmaphyta, a new family Parmoligocenaceae, a new genus Parmoligocena and a new species Parmoligocena janusii. Other remains are reminiscent of the extant genus Pentalamina and for this we propose a new genus and species, Pentalaminamorpha radiata. The taxonomic affinity is less certain for other nannofossils found, as they are only somewhat similar to parmaleans, and so we only tentatively associate them with this group. All these fossils occur together with a diverse assemblage of diatoms (mostly from Leptocylindrales, Rhizosoleniales, Coscinodiscales, Cymatosirales, and Hemiaulales), silicoflagellates (mostly species from the genus Corbisema) and archaeomonads. Together they suggest the palaeoenvironmental context for the parmaleans, a neritic marine environment, thus similar to where silicified parmaleans can be found today.

Ornithosuchids are a Late Triassic pseudosuchian archosaur group, consisting of four species (three from South America, and one from Scotland). All of them have triangular skulls with a protruding premaxilla, large nostrils, an extensive diastema in their narrow snout, a short jaw that does not reach the anterior end of the skull, and serrated posteriorly curved teeth. For this clade, carnivorous and scavenger habits have been previously proposed. Within the Ornithosuchidae, Riojasuchus tenuisceps (from Argentina) has the most morphologically extreme characteristics. Based on CT scans of the preserved skulls we generated a 3D model, and over this, we estimated the volumes of the adductors and abductor muscles and the force exerted by each. From these data we built the finite element model and measured the bite force (1.8-2.3 kN). Lateral, tractive, and torsional forces were applied to the end of the snout to evaluate the structural response of the skull during feeding. The results show that R. tenuisceps could resist tractive and torsional stresses better than lateral stress. Additionally, we analysed the peculiar morphological characteristics of the skull and their functional implications. We observed that the upper and lower dental rows were laterally separated from each other, preventing the generation of a cutting line during occlusion, and therefore, R. tenuisceps would have fed on small-sized prey that it could swallow whole. The curved premaxilla and the short mandible would not allow it to bite with the tip of the snout (ruling out the scavenging hypothesis), but were instead more adequate to capturing prey suspended in a fluid. This set of results allows us to propose that R. tenuisceps could have had a zoophagous diet and a wading habit, being able to feed on fish, amphibians, or any small animals that they could catch from the shoreline.

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The polychaete borings Caulostrepsis taeniola, Caulostrepsis cretacea, Caulostrepsis avipes, Caulostrepsis penicil lus isp. nov., Maeandropolydora elegans, Maeandropolydora sulcans, Sulcichnus sigillum, the bryozoan boring Pinaceocladichnus onubensis and the phoronid boring Talpina cf. hackberryensis occur in coralla of the solitary scleractinian coral Ceratotrochus (Edwardsotrochus) duodecimcostatus in the upper Pliocene middle/lower neritic to upper bathyal fine-grained deposits of NE Tunisia. This very rich assemblage of borings is produced in vivo as suggested by (i) their occurrence close to the surface and mostly in the upper part of coralla (Caulostrepsis ispp., M. elegans), even if they are known to penetrate deeply in the substrate, or (ii) evidence of corallum deformation in response to the boring action (Sulcichnus sulcans). The remaining borings were probably produced post mortem; they penetrate deeply into the corallum (M. sulcans) or always occur shallowly in the substrate (Talpina) and, in addition, cross cut other borings (Pinaceocladichnus). The polychaete borings are dominant. The abundance of the borings is probably caused by ecological pressure from shallower zones in subtropical waters. This resulted in the colonization of hard, small-sized substrates located in relatively deep (offshore) waters. The interpretation of age and palaeoenvironment was elucidated by the analysis of benthic and planktonic foraminifers. K ey w o r d s : Anthozoa, palaeoecology, ichnotaxonomy; commensalism, Pliocene, Mediterranean basin.