The Pleistocene Equus (Amerhippus) and hippidiforms frequently occur together in the South American fossil record, suggesting a possible case of sympatry and syntopy. Although resembling each other in their overall morphology, their rostra show distinct differences. While Equus (Amerhippus) resembles extant horses, hippidiforms are characterised by slender nasal bones, a retracted nasal notch at the level of M2–M3 or posterior to M3, and the presence of dorsal preorbital fossae of variable depth. Here we present an anatomical reconstruction of the muzzle of hippidiforms based on homologous patterns in the extant horse Equus caballus, together with a morphofunctional analysis of their rostra and a comparative analysis of premaxillary shape. The rostral morphology of hippidiforms suggests the presence of a developed upper lip with prehensile function, as occurs in extant black rhinoceros. This prehensile structure could be ecomorphologically related to browsing, thus reducing niche overlap with Equus (Amerhippus), and hence competitive pressure.

Neohelos is a geographically and temporally widespread genus of Cenozoic diprotodontid marsupials commonly used to biocorrelate otherwise undated Australian fossil deposits. Here, we revise the genus and describe two new species from the Riversleigh World Heritage Area of northwestern Queensland. Neohelos solus sp. nov. is a small, relatively abundant, plesiomorphic form, while the rarer, larger Neohelos davidridei sp. nov. is the most derived species of the genus with an upper premolar morphology that is structurally antecedant to members of the Late Miocene genus Kolopsis. Additional material of Neohelos tirarensis and Neohelos stirtoni is described. A chronological morphocline is evidenced by a gradual change in morphology accompanied by an increase in size from Ne. tirarensis through Ne. stirtoni to Ne. davidridei, and is generally consistent with the biostratigraphic distribution of Neohelos species throughout Riversleigh's faunal zones A to D. Stage of evolution biocorrelation of Neohelos species confirms that some of Riversleigh's Faunal Zone A deposits are Late Oligocene in age and predate the Wipajiri Formation of South Australia. Strong faunal correlations exist between Riversleigh's topographically low to middle Faunal Zone C deposits and the Northern Territory's Middle Miocene Bullock Creek Local Fauna. The presence of the highly derived N. davidridei in the Jaw Junction Local Fauna of Riversleigh's Upper Faunal Zone C suggests a later Middle Miocene (post-Bullock Creek) age for this deposit.

Two new species of miniature owls are described from the upper Pleistocene asphalt deposits of Rancho La Brea, California. The first is assigned to the extant genus Glaucidium, as Glaucidium kurochkini sp. nov., and the second is placed in a new genus Asphaltoglaux, as Asphaltoglaux cecileae sp. nov. Both new species are based on tarsometatarsi, and each is represented by various elements. These are the second and third extinct owls to be described among the nine strigiform species from Rancho La Brea. The new species of Glaucidium is also recognized from the upper Pleistocene asphalt deposits of Carpinteria, California, which lends support to the hypothesis that southwestern coastal California was comparable to an island in the late Pleistocene. Recognition of these two new strigiform taxa brings to 22 the number of known extinct avian species from Rancho La Brea.

Herein we describe deinonychosaurian (Dinosauria: Theropoda) tracks in the Lower Cretaceous Hekou Group at sites I and II of Liujiaxia Dinosaur National Geopark, Gansu Province, China. The site preserves 71 didactyl tracks, the largest concentration of deinonychosaurian tracks in Asia. The tracks pertain to a new dromaeopodid ichnospecies: Dromaeosauripus yongjingensis ichnosp. nov., which is diagnosed by: a digital pad formula of x-1-3-4-x and a mean divarication angle between digits III and IV of 19°, and having the proximal portion of digit II contacting the anterior margin of a large, rounded metatarsophalangeal pad. Six Dromaeosauripus trackways from site II comprise at least two, and possibly three, turning trackways in which the track maker(s) turned without slowing down. None of the Dromaeosauripus trackways are parallel or closely spaced, suggesting that they were made by solitary track makers. Estimates of dromaeopodid track-maker sizes are between 61–300 cm, well within the size range established by body fossils of both dromaeosaurids and troodontids.

Iberovaranus Hoffstetter, 1969 was erected as a monotypic genus of varanine varanid lizard on the basis of a single trunk vertebra from the Miocene of Spain. Thanks to the study of the holotype, as well as of a still undescribed cervical vertebra from the same locality, we show that the vertebral morphology of Iberovaranus is contained within the known variability of Varanus. Therefore, Iberovaranus Hoffstetter, 1969 is considered a subjective junior synonym of Varanus Merrem, 1820, and the species Iberovaranus catalaunicus Hoffstetter, 1969 should be considered a nomen dubium.

The skeletal anatomy of the Early Triassic (Induan) procolophonid reptile Sauropareion anoplus is described on the basis of three partial skeletons from Vangfontein, Middelburg District, South Africa. Together these three specimens preserve the large majority of the pectoral and pelvic girdles, articulated forelimbs and hindlimbs, and all but the caudal portion of the vertebral column, elements hitherto undescribed. Our phylogenetic analysis of the Procolophonoidea is consonant with previous work, positing S. anoplus as the sister taxon to a clade composed of all other procolophonids exclusive of Coletta seca. Previous studies have suggested that procolophonids were burrowers, and this seems to have been the case for S. anoplus, based on comparisons with characteristic skeletal anatomy of living digging animals, such as the presence of a spade-shaped skull, robust phalanges, and large unguals.

Based on newmaterial from Germany and Spain, the echinoid “Lepidocentrus” ibericus from the Early Devonian (Emsian) of northern Spain is shown to be congenericwith Rhenechinus from the Hunsrück Slate of south-western Germany. New information on the lantern, pedicellariae and internal structure of the theca is provided, and confirms this genus as amember of the Echinocystitidae—Proterocidaridae clade and the most primitive of all Devonian echinoids. The two environmental settings in which Rhenechinus is found are very different: the Spanish specimens come from a relatively shallow—water bryozoan meadow setting while the German specimens are preserved in a deep-water setting.We deduce that the rare echinoid specimens from the Hunsrück Slate are all allochthonous, whereas the Spanish material is preserved in situ.

A new species of rhenopyrgid edrioasteroid Rhenopyrgus piojoensis sp. nov. is described form the Silurian (Lower Ludlow) Los Espejos Formation in the Precordillera of Argentina. This species is the first reported edrioasteroid from South America. Rhenopyrgids are widely distributed in Ordovician through Devonian deposits of most continents. Numerous juvenile specimens show that the general bodyplan is organized early in ontogeny and that the pedenculate zone lengthens with age. Phylogenetic analysis shows that rhenopyrgids are more closely related to edrioasterid edrioasteroids such as edrioblastoids and cyathocystids than to pyrgocystid isorophids.

Six shells belonging to a muricid gastropod species were recovered from a Pleistocene marine raised beach located on Navarino Island, in southern South America. None of the living species in the Beagle Channel or in the area is close, and none of the fossil species in the vicinity regions shows the diagnostic characters of the Navarino Pleistocene fossils. Our material resembles Lepsiella baileyana from southern Australia, although some differences in the suture and in the spire outline are recognized. Haustrinae were previously confined geographically to New Zealand and to the temperate coast of Australia, now extending its range of distribution to southern South America. This finding of Lepsiella ukika sp. nov. is best explained on the basis of transoceanic migration from Australasia by means of the Antarctic Circumpolar Current perhaps during a Quaternary glacial period. The presence of this Pleistocene visitor in southern South America is important because it clearly demonstrates that transcontinental traverse of taxa with direct (non-planktonic) development might have happened by rafting on kelp that served as transport platforms.

Strombids are frequent fossils in Neogene nearshore deposits but are rarely used for biostratigraphy due to their poorly defined stratigraphic ranges. Herein, we document the biostratigraphic value of the group based on a succession of short-lived distinct species in Neogene deposits in the circum-Mediterranean area. These have been intermingled so far into two “super-species”, viz. Persististrombus bonelli and P. coronatus, seemingly ranging from the Oligocene to the Pliocene. Based on morphometric measurements on 219 specimens we refine the taxonomic concept for this group and document at least 5 distinct species of high biostratigraphic and biogeographic significance. European Persististrombus species display a tendency to produce strongly sculptured populations with marked spines or to form populations with elongate shells and reduced sculpture. The development of sculptured morphs is an iterative process as exceptionally sculptured taxa occur in stratigraphically and geographically discrete phases and areas. Yet, within these species the morphology is very variable. Although some of these taxa are distinct species, there is no continuous evolutionary lineage leading to the Pliocene P. coronatus with which some of these taxa were confused in the literature so far. Successfully reproducing populations of extant species of Persististrombus in the Panamic Province and the African-Eastern Atlantic Province are limited in their distribution by the 20°C isotherm. This value may thus be a realistic estimate for the cool-season sea surface temperatures for Persististrombus-bearing formations. Persististrombus pannonicus sp. nov. is established for a late Badenian species.

About 150 Mesozoic (mostly Early and Middle Jurassic) species of the heterobranch superfamily Mathildoidea are classified into four families and 27 genera. Most taxa are assigned to the families Mathildidae, Gordenellidae, and Tofanellidae while the Triassic family Anoptychiidae holds only a single genus and is restricted to the Late Triassic. Mathilda janeti is designated as type species for the genus Promathildia. Earlier designations are invalid because they refer to species which were not originally included in the genus Promathildia. As a consequence, Promathildia is transferred fromMathildidae to Gordenellidae. The generic assignment of numerous mathildoid species is changed. The suggested classification represents an arrangement which is based on shell characters; it is not based on a cladistic phylogenetic analysis.However, a great number of fossil taxa can only be classified based on shell characters. A high mathildoid diversity has been recognized from the Late Triassic Cassian Formation. Many of these taxa are unknown form the Jurassic and probably became extinct during the end-Triassicmass extinction event.However, at least five genera (probably eight) survived the end-Triassicmass extinction event. Tricarilda, Jurilda, and Promathildia are rather conservative, long ranging groups of high Jurassic species diversity. They probably gave rise to the modern Mathildidae. One new genus is described: Angulathilda gen. nov.

We report on the discovery of large cephalopod arm hooks (mega−onychites) from the Kimmeridgian and Volgian of Spitsbergen (Agardhfjellet Formation). This includes a largely uncompressed hook in a seep carbonate,with preservation of surface sculpture. We suggest the use of logarithmic spirals as morphological descriptors for the outer part of cephalopod arm hooks, with implications for systematics and functional morphology. Comparison with Upper Jurassic material from Greenland, northern Norway and the North Sea demonstrates a remarkably consistent morphology, which we assign to the same form species, Onychites quenstedti. Considering the relatively small stratigraphic (Kimmeridgian— Volgian) and biogeographic (Boreal) range of this large form, it is likely that it represents a single biological species or genus.

This paper discusses the phyletic interpretation of the genus Phricodoceras and its taxonomic classification at the subfamily, family, and superfamily levels from an historical and critical perspective. First a review of the latest find ings on this taxon is presented and the grounds for the attribution of Phricodoceras to the Schlotheimiidae (Psiloceratoidea) are summarized and illustrated. This review is a synthesis grounded on evolutionary (e.g., heterochronies, innovations), eco-ethological (e.g., assumed shell hydrodynamic capacities) and spatio-temporal pat terns (e.g., bio-chronostratigraphy, palaeobiogeography). Then, the main stages of understanding the taxonomy of Phricodoceras since the early nineteenth century are reviewed. Two main taxonomic concepts alternate over time. The first is based on the “overall resemblance” of Phricodoceras to some coeval Eoderoceratoidea leading to the genus be ing included in its own family or subfamily (e.g., Phricodoceratinae) among the Eoderoceratoidea. The second hypoth esis, recently confirmed by the discovery of an intermediate form (i.e., Angulaticeras spinosus), clearly includes Phricodoceras within the Schlotheimiidae (Psiloceratoidea). Comparison of these two very different conceptions re veals how “overall resemblance” can be misleading and shows that the discovery of intermediate forms is often the key to phyletic reconstructions in ammonites.

Trilobites from mudstone of the Upper Ordovician Xiazhen Formation of South China are described. The reef-associated, unique fauna comprises 25 species, 14 genera, and ten families. Five new species are named: Remopleurides xiazhenensis sp. nov., Hibbertia aodiensis sp. nov., Vietnamia yushanensis sp. nov., Ceraurinus zhuzhaiensis sp. nov., and Pliomerina tashanensis sp. nov. The paucity of trilobites in reef-associated carbonates is interpreted that the trilobites diversified after the reef system decimated. Compared to the Late Ordovician trilobite faunas in other areas of South China, the Xiazhen mudstone fauna is unique in that the phacopids including Vietnamia, Ceraurinus, and Pliomerina account for 75% of the specimens collected. The occurrence of the same trilobite assemblage at different sampling localities along the dip direction of the formation suggests that the outcrops may be overlapped due to structural movement. The Xiazhen trilobite fauna is unique among the Late Ordovician fauna in that it is predominated by phacopids and associated with reef.

The enigmatic Svalbard Palaeocene fossil taxon Hymenopterites deperditus is revised, and is neither a wasp nor a plant seed, but turns out to be a bug hemelytra corresponding to the oldest described reduviid bug. It can be attributable to the “emesine-saicine clade”. The presence in the Svalbard Palaeocene of this insectivorous bug, showing possible mimicry of a wasp model, confirms the presence of diverse entomofauna and of rather warm palaeoclimatic conditions.