The first records of the upper Cambrian agnostoid genera Kormagnostella, E. Romanenko, in Romanenko and Romanenko, 1967, and Biciragnostus F. Ergaliev, in Eraliev and Ergaliev, 2001, in Laurentian North America are from a narrow stratigraphic interval in the Steptoean–Sunwaptan boundary interval (Furongian, Jiangshanian) of Nevada and Utah. In Nevada, both genera occur in a condensed bioclastic lag below a major flooding surface, and Kormagnostella also appears in a transgressive interval in Utah. Immigration of these genera is associated with sea level rise, and also with faunal turnover. Biciragnostus is confined to the latest Elvinia Zone, immediately below the onset of a trilobite and agnostoid extinction event at the base of the Irvingella major Zone (basal Sunwaptan). Kormagnostella is present in the latest Elvinia Zone, and has its highest occurrence in the I. major Zone. Stratigraphic data from the Karatau-Naryn Terrane, Kazakhstan indicate that both genera disappear near the local extinction of Irvingella, suggesting that faunal turnover in that region may have been broadly correlative with the more profound extinction in Laurentia. New species are Kormagnostella advena, K. insolita and Biciragnostus viator.

A paleoecological study of benthic foraminifera through the lower Hettangian in the Doniford Bay section (west Somerset, U.K.) is presented. The sudden and brief appearance of Oberhauserellidae in the aftermath of the Late Triassic extinction is defined as a proxy for environmental perturbations indicating severe biotic stress conditions. Oberhauserellidae, associated with the genus Reinholdella are distinguished from other species by a high abundance, low diversity, high dominance and an abnormally small size. This suite of characters mimics an opportunistic behavior where these r-strategists and grazer feeders maximize their full ecological potential at a time of low-oxygen conditions on the sea-floor and a high food supply: both of which appear to be the main triggers of this paleoecological change. The disappearance of these opportunistic benthic foraminifera coincides with the appearance of infaunal, low-oxygen-tolerant generalists, and the restoration of stable environmental conditions (e.g., well-stratified water mass and oligotrophic conditions), characterizing the initial stages of recovery following the Late Triassic extinction event.

Bathymodiolin mussels are a group of bivalves associated with deep-sea hydrothermal vents and other reducing deep-sea habitats, and they have a particularly rich early Cenozoic fossil record in western Washington State, U.S.A. Here we recognize six species from middle Eocene to latest Oligocene deep-water methane seep deposits in western Washington. Two of them are new: Vulcanidas? goederti from the middle Eocene Humptulips Formation and Bathymodiolus (sensu lato) satsopensis from the late Oligocene part of the Lincoln Creek Formation. Very similar to the latter but more elongate are specimens from the early Oligocene Jansen Creek Member of the Makah Formation and are identified as B. (s.l.) aff. satsopensis. Bathymodiolus (s.l.) inouei Amano and Jenkins, 2011 is reported from the Lincoln Creek Formation. Idas? olympicus Kiel and Goedert, 2007 was previously known from late Eocene to Oligocene whale and wood falls in western Washington and is here reported from Oligocene seep deposits of the Makah and Pysht Formations. Vulcanidas? goederti occurs at a seep deposit from a paleodepth possibly as great as 2000 m, suggesting that its living relative, Vulcanidas insolatus Cosel and Marshall, 2010, which lives at depths of only 150–500 m, is derived from a deep-water ancestor. The bathymodiolins in western Washington indicate that the group originated at least in the middle Eocene and underwent a first diversification in the late Eocene to Oligocene. Early ontogenetic shells of all fossil species investigated so far, including the middle Eocene Vulcanidas? goederti, reflect planktotrophic larval development indicating that this developmental mode is an ancestral trait of bathymodiolins.

A small assemblage of shelly fossils, dominated by the brachiopod Treptotreta jucunda and the bradoriid arthropod Mongolitubulus aspermachaera new species is described from a Furongian limestone of Västergötland, south-central Sweden. Mongolitubulus aspermachaera is represented in the assemblage by individual valves and numerous, ornamented spines. Valves and spines share identical ornament and microstructure leaving no doubt that the isolated spines were once attached to the bradoriid valves. Mongolitubulus aspermachaera adds to the increasing list of spinose Cambrian bradoriid arthropods, and Mongolitubulidae new family is erected here to incorporate the genera Mongolitubulus, Tubuterium and Spinospitella. Mongolitubulus aspermachaera represents the youngest member of the new family and supplements the biodiversity of bradoriids in the Furongian, an interval when bradoriid diversity is considered to be very much on the decline. The brachiopod Treptotreta jucunda described predominantly from the ‘middle' to ‘late' Cambrian of Australia is here documented for the first time from outside Gondwana, dramatically extending the biogeographical range of the species. Other elements of the faunal assemblage include typical Baltic Furongian representatives, such as the trilobite Parabolina, the agnostoid Agnostus and the phosphatocopids Hesslandona and Vestrogothia.

A new penaeoid shrimp collected from the Middle Triassic Member II of the Guanling Formation in the vicinity of the city of Luxi, Yunnan, southwest China, is a new species, Aeger luxii n. sp. The new species possesses prominent spinose third maxillipeds, which is one of the typical characteristics of Aeger. The new species differs from the type species, Aeger tipularius from the Jurassic Solnhofen Plattenkalk, in having a long, smooth rostrum with no subrostral spines. The new taxon increases the diversity of Chinese decapods, and further expands our knowledge of the phylogeny and evolution of the Mesozoic decapods. The find is the first complete specimen of Aeger in the Middle Triassic, and reveals a close biogeographic connection of the marine ecosystem between Eastern and Western Tethys.

The bizarre morphology of living Pycnogonida, known colloquially as sea spiders, has long fueled dissent over their status within the arthropods. Pycnogonids figure prominently in recent analyses of anterior limb homologies and ancestral crown-group euarthropod relationships, with support for the concept of Pycnogonida as sister taxon to Euchelicerata now contested by proponents of a more basal position between Radiodonta and all other arthropods. A challenge to further elucidation of their phylogenetic position is the exceptional rarity and disjunct distribution of pycnogonids in the fossil record, due largely to their fragile unmineralized exoskeletons. New fossil discoveries therefore have the potential to add significantly to knowledge of their evolution, paleoecology, and paleobiogeography. Here we report the first known occurrence of fossil pycnogonids from rocks of Ordovician age, bridging a 65 Myr gap between controversial late Cambrian larval forms and a single documented Silurian specimen. The new taxon, Palaeomarachne granulata n. gen. n. sp., from the Upper Ordovician (ca. 450 Ma) William Lake Konservat-Lagerstätte deposit in Manitoba, Canada, is also the first reported from Laurentia. It is the only record thus far of a fossil sea spider in rocks of demonstrably shallow marine origin. Four incomplete, partially disarticulated molts represent a relatively large, robust animal with a series of five segment-like elements in a ‘head’ region that does not incorporate the first of four preserved limb-bearing trunk segments. This unique pattern may reflect the plesiomorphic condition prior to complete fusion of anterior ‘head’ elements and first trunk segment to form a cephalosoma, as seen in all eupycnogonids. Palaeomarachne granulata is interpreted as occupying a basal stem-group position in the Pycnogonida.

Strophomenid brachiopods have long been interpreted as “snowshoe” strategists, with their flattened concavo-convex valves providing resistance to foundering in very soft sediments. There has been a sharp difference of opinion in whether the shells were oriented with their convex or their concave surface in contact with the sediment. This study, along with independent evidence from sedimentology, ichnology, and morphology, indicates that the strophomenids lived with their shells concave down (convex up). Experiments indicate the force required to push shells into soft cohesive muds is much greater for the convex up than for the convex down orientation. Forces also increase with shell curvature. All measured forces greatly exceed estimates of the downward force exerted by the weight of the shell, indicating that foundering resistance may not have been the key functional requirement. Instead, a convex up orientation would have provided resistance to overturning in currents, in particular if the valves gaped widely. The “snowshoe” may not be the relevant paradigm for the shell morphology of these forms. An alternative is that they functioned more as a tip-resistant base, similar to those of garden umbrellas or stanchions.

The Early Permian (Asselian) Euramerican plant Padgettia readi Mamay is reassigned to Odontopteris Brongniart, as O. readi (Mamay) Stull et al. n. comb. Distinctive elongate structures on neuropteroid pinnules of this plant, previously interpreted as fructifications, are herein reinterpreted as foliar histoid galls, structurally analogous to blister or vein galls, and probably induced by an early lineage of hemipterans or mites. These distinctive features are assigned to the new gall ichnogenus Ovofoligallites Labandeira, n. ichnogen. n. ichnosp, as O. padgetti Labandeira. The Early Permian association between an Odontopteris host and Ovofoligallites gallers probably originated during the Middle Pennsylvanian as a similar, antecedent association between Macroneuropteris scheuchzeri (Hoffmann) Cleal, Shute, and Zodrow and the maker of U-shaped surface features long known as a distinctive, unattributed damage type, but now recognizable as a likely gall. The persistence of this association between the galler and certain medullosan pteridosperms into the Permian adds to the morphological richness of the Permian galler insect fauna. The Permian ecological expansion of galling insects resulted in colonization of new host plants, primarily through a shift from the consumption of entire, mostly pteridophyte axial organs during the Pennsylvanian to the partitioning of seed plant tissues in leaves and small branches in the Permian. The Ovofoligallites galler was part of a diverse Permian galler guild involving a variety of plant taxa, organs and tissues that overwhelmingly targeted multiple lineages of seed plants.

Quaternary raised marine terraces containing the remains of diverse, shallow water marine invertebrate faunas are widespread across the coast of Angola. These deposits and faunas have not been studied in the same detail as contemporaneous features in northwest and southernmost Africa. We analyzed the fossil assemblages and sedimentology of two closely spaced middle Pleistocene marine terrace deposits in Baía das Pipas, southwest Angola. This revealed 46 gastropod and 29 bivalve species, along with scleractinian corals, encrusting bryozoans, polychaete tubes, barnacles, and echinoids. The fauna is characteristic of intertidal and nearshore rocky substrates and sandy soft-bottom habitats. Sedimentological analysis is consistent with faunal data and indicates an upper shoreface paleoenvironment along a gravel coast. This diverse fauna stands out as a rare example of a marine Pleistocene assemblage from over 6,000 km of the West African coast. The assemblage is dominated by extant tropical West African molluscs, including species from the “Senegalese fauna” that colonized northern Africa and beyond during Pleistocene interstadials. Additionally, as along the modern coast of the Namibe Desert, the influence of the cool-water Benguela Current is apparent in the paleofauna by the occurrence of a few temperate species. The distribution and thermal tolerances of extant species identified in the Pipas fauna indicate that this region experienced similar climatic and oceanographic conditions as that of the present during this interstadial. Seasonal temperature varied between ∼20 and 28°C and resulted from upwelling in this tropical setting.

Shells and opercula of bithyniid gastropods assigned to Gabbiella are found in high abundance in the Pleistocene upper Burgi and KBS Members of the Koobi Fora Formation, Turkana Basin, northern Kenya. The systematic paleontology of the Turkana Basin Gabbiella is revised herein based on morphological comparison with the opercula of other Recent African bithyniids. The fossils from the upper Burgi and KBS Members are here assigned to Gabbiella rosea Mandahl-Barth, 1968, a species not known from the Turkana fossil record before, but extant in this lake today. A sampling and taphonomic bias is identified which influences the relative abundance of Gabbiella shells and opercula, as a mesh size of 0.63 mm or less is necessary to capture all opercula preserved in the sediments. Accordingly, opercula were found to be significantly more abundant than shells, indicating a different preservation potential of shells and opercula, as the calcitic operculum is more robust than the aragonitic shell. In contrast to previous arguments that most shellbeds in the Turkana Basin sequence represent undisturbed life assemblages, a taphonomic bias is clearly evident reducing the fidelity of the Turkana Basin mollusk assemblages.

The brachiopod genus Dicoelosia is generally considered a typical deep-water taxon. New data suggest that some species of the genus may have invaded relatively shallow-water habitats during its geological history. However, there is scant evidence for its invasion of shallow-water environments after the terminal Ordovician mass extinction. Dicoelosia occurs in the shallower-water benthic shelly assemblages of the lower Niuchang Formation (upper Rhuddanian, Llandovery) of Meitan County, northern Guizhou Province, South China. Evidence of a move to shallow water includes its morphology and population structure, regional paleogeography, sedimentology, together with the abundance and diversity of its shallow-water associates. Following the biotic crisis, deep-water environments were barely habitable, and may have driven Dicoelosia into shallower-water niches. The taxon endured the less suitable shallow-water environments until the deep-water benthic zones ameliorated after the recovery, implying a shallow-water refugium existed after the biotic crisis. A new species Dicoelosia cathaysiensis is erected herein. There is only one record of this genus in South China and this unique occurrence may reflect the distinctive paleobiogeography and environments of this region.

The west coast of North America record of the shallow-marine stromboid gastropod genus Rimella Agassiz, 1841 is restudied for the first time in 90 years. This genus comprises a small group of Paleogene gastropods characterized by having an ornamented fusiform shell, a posterior canal ascending the spire, and simple (non-flared) outer lip. Rimella, whose familial ranking has been inconsistent, is placed here in family Rostellariidae Gabb, 1868, subfamily Rimellinae Stewart, 1927. Ectinochilus Cossmann, 1889; Macilentos Clark and Palmer, 1923; Vaderos Clark and Palmer, 1923; and Cowlitzia Clark and Palmer, 1923 are recognized here as junior synonyms of Rimella. Four species are recognized from the west coast of North America: early to middle Eocene Rimella macilenta White, 1889; early Eocene Rimella oregonensis Turner, 1938; middle to late Eocene Rimella supraplicata (Gabb, 1864) new combination, of which Rostellaria canalifer Gabb, 1864, Cowlitizia washingtonensis Clark and Palmer, 1923, and Cowlitzia problematica Hanna, 1927 are recognized here as junior synonyms; and late Eocene Rimella elongata Weaver, 1912.

Rimella was a warm-water gastropod whose earliest known record is of early Paleocene (Danian) age in Pakistan. Other than the west coast of North America, Rimella is found in Eocene strata in western Europe, Turkey, Egypt, Pakistan, southeastern United States, Panama, Peru, and, to a lesser degree, in Trinidad, Columbia, Java, and New Zealand. Global cooling near the end of the Eocene greatly diminished the genus. Its youngest known occurrences are of early Oligocene age in Germany, Italy, England, and Peru.

The thickness ratios of shells (=whorl breadth/shell diameter) in the heteromorphic scaphitid ammonoid Scaphites planus (Yabe, 1910) from the lower middle Turonian in the Oyubari and Kotanbetsu areas of Hokkaido, Japan were examined in order to determine their mode of migration. The thickness ratios of S. planus differ significantly between the two localities, which suggest that these different populations did not frequently migrate between the two areas (currently ∼130 km apart, although the actual distance during Turonian is uncertain due to the presence of faults and folds between the two areas). There is no difference in hatchling diameters between the two areas, suggesting that the thickness ratios became manifested after the post-hatchling stage due to limited migration with in a nektobenthic habitat. This study suggests that scaphitid ammonoids became nektobenthic with limited migration at a stage earlier than previously thought (not during the transition from normal to abnormal coiling). The limited migration in scaphitid ammonoids might relate to their higher evolutionary volatility.

Rare scales of agnathan thelodonts Paralogania ludlowiensis and Thelodus sp. cf. T. parvidens, or alternatively Thelodus macintoshi, and acanthodian fishes Nostolepis striata, Gomphonchus sp., Gomphonchoporus sp. aff. G. hoppei, and Machaeraporus stonehousensis (Legault) n. gen., plus acanthodian fin spines, teeth and tooth whorls have been identified from the upper Moydart and Stonehouse formations near Arisaig, Nova Scotia. The assemblage agrees well with the late Silurian (uppermost Ludlow–Přídolí) age assigned to these strata based on invertebrate assemblages, and the vertebrate taxa show affinity with British and Baltic faunas of this age. All vertebrate-bearing strata were deposited in various positions off the western shores of the Avalonia terrane during or after its collision with Laurentia.

Turtles have served as a model system for molecular divergence dating studies using fossil calibrations. However, because some parts of the fossil record of turtles are very well known, divergence age estimates from molecular phylogenies often do not differ greatly from those observed directly from the fossil record alone. Also, the phylogenetic position and age of turtle fossil calibrations used in previous studies have not been adequately justified. We provide the first explicitly justified minimum and soft maximum age constraints on 22 clades of turtles following best practice protocols. Using these data we undertook a Bayesian relaxed molecular clock analysis establishing a timescale for the evolution of crown Testudines that we exploit in attempting to address evolutionary questions that cannot be resolved with fossils alone. Some of these questions, such as whether the turtle crown originated in the Triassic or Jurassic, cannot be resolved by our analysis. However, our results generate novel age-of-origination estimates for clades within crown Testudines. Finally, we compare our fossil calibrations and posterior age estimates to those from other studies, revealing substantial differences in results and interpretation.

Fifteen limnic ostracodes species have been recorded in the Alagamar Formation, Potiguar Basin: Cypridea araripensis Silva, 1978a; Cypridea? sp., Harbinia sinuata (Krömmelbein and Weber, 1971); Harbinia crepata n. sp., Harbinia dimorphica n. sp., Harbinia alta Antonietto et al., 2012; Paracypria? elongata n. sp., Ilyocyprimorpha berthoui (Colin and Dépêche, 1997); Ilyocypris? sp., Brasacypris subovatum n. sp., Candona? sp., Theriosynoecum colini n. sp., T. guzzoi n. sp., T. silvai (Silva, 1978b) diagnosis emended by Do Carmo et al. (2004b); and Darwinula martinsi Silva, 1978c diagnosis emended by Do Carmo et al. (2004b). Nine of these species have also been recorded outside of the Potiguar Basin, either in other Cretaceous basins in Brazil or coeval strata in western Africa. Despite the controversy about dating the local Alagoas Stage and the relatively large range of the Zone Harbinia spp. 201–218, the material studied in this paper belongs to the interval corresponding to the well-defined palynological zone coded as P-270, which is mid-upper Aptian in age.

The discovery of a new species, Cyclolampas altus new species in the upper Callovian of Burgundy (France) leads to the systematic revision of the rare echinoid genus Cyclolampas Pomel, 1883. Two morphometric approaches are used jointly to describe and quantify variations in test shape: the analysis of linear measurements and the Elliptic Fourier shape analysis. Both analyses yield congruent results that highlight the amplitude of within-species variations and quantify the part due to allometry. Along with the description of C. altus, the systematic position of species formerly assigned to the genera Pygorhytis Pomel, 1883 and Cyclolampas is amended. Previously attributed to the genus Pygorhytis, Cyclolampas castanea (Desor, 1858) is reassigned to the genus Cyclolampas on the base of new observations. Conversely, the examination of the Bajocian species Pygorhytis kiliani (Lambert, 1909) and Pygorhytis gillieroni Desor in Desor and de Loriol, 1872, which were previously assigned to Cyclolampas now supports their taxonomic reassignment to the genus Pygorhytis. Finally, the two species Cyclolampas verneuili (Cotteau, 1870) and Cyclolampas cotteaui Mintz, 1966 (nomen nudum) are considered junior synonyms of the genus type species Cyclolampas voltzii (Agassiz, 1839). The questioned origin date of the genus, estimated either to the Bajocian or to the Oxfordian, is now clearly established to be upper Callovian. These new results fit well with the overall scheme of atelostomate echinoid evolution and migration to deep-sea environments during the Middle and Upper Jurassic.

Bivalves have pursued an infaunal lifestyle since early in their history. Trace fossils that have been attributed to the infaunal activity of bivalves include Hillichnus, Lockeia (=Pelecypodichnus), Lophoctenium, Protovirgularia, Ptychoplasma, Siphonichnus and Scalichnus. Re-evaluation of the ichnogenera Siphonichnus and Scalichnus supports consolidation into a single ichnogenus, Siphonichnus, which has taxonomic precedence.

Siphonichnus, as redefined herein, presently includes four ichnospecies. Siphonichnus eccaensis Stanistreet et al. is an unlined vertical tube characterized by concave downward laminae penetrated by a single central shaft and is interpreted to reflect downward burrowing in response to net erosion during the life span of the animal. Siphonichnus phiale (Hanken et al., 2001) is characterized by concave upwards laminae and reflects equilibrichnial behavior by the tracemaker. Siphonichnus lepusaures n. isp. is characterized by concave upwards laminae with a pair of vertically oriented, unlined tubes at the top and is interpreted as the dwelling trace of a bivalve with paired siphons responding to sediment aggradation. Siphonichnus sursumdeorsum n. isp. is characterized by concave upwards laminae in its basal third and convex upwards laminae in its upper third and is interpreted as the dwelling trace of a bivalve exhibiting equilibrichnial behavior in a dynamic depositional setting. Consolidation of these ichnotaxa into a single ichnogenus simplifies the ichnotaxonomy and provides a means of assessing the sedimentological significance of bivalve-generated dwelling/equilibrium/escape structures.

A set of 127 binary and multistate characters, weighted by the number of derived character states, degree of covariation, and level of homoplasy, was used in a cladistic analysis of type species representing 12 genera previously assigned to families Monticuliporidae and Mesotrypidae. The most parsimonious tree consisted of a 10-genus monophyletic crown group with the remaining two genera forming a basal paraphyletic stem group. The composition of the monticuliporid crown group is broadly similar to two earlier classifications while stem group membership matches the family Mesotrypidae. Phenetic groupings, based on overall morphological similarity, have memberships that are similar to those of clades but provide no means of determining the polarity of evolutionary relationships either within or between them. Finally, only the observed stratigraphic ranges of the type species of genera provide a statistically significant match with cladistic branching sequence, perhaps because current composite generic ranges reflect the mixing of species belonging to different genera. Based on cladogram topology, we propose the placement of all 12 genera into a single family Monticuliporidae.

Fine-grained sandstones and siltstones of Late Cretaceous to Eocene age in Antarctica and Tierra del Fuego yield an association of well-known shallow-marine trace fossils. Among them stick out complex spreite burrows, which are formally described as Euflabella n. igen. and subdivided into five ichnospecies with different burrowing programs and occurrences. As shown by concentrations of diatoms, radiolarians, foraminifers, and calcispheres in particular backfill lamellae, the unknown trace makers lived on fresh detritus from the surface as well as the burrowed sediment. In some ichnospecies, vertical sections show that the spreite is three-dimensionally meandering in upward direction and that upper laminae tend to rework the upper backfill of the folds underneath. This could mean a second harvest, after cultivated bacteria had time to ferment refractory sediment components, which the metazoan trace maker had been unable to digest before.