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.

A new agelacrinitid edrioasteroid, Multiplexidiscus mckenziensis n. gen., n. sp. is described from the middle Silurian upper McKenzie Shale Member of the Mifflintown Formation of Pennsylvania. These edrioasteroids were attached to a large hardground clast that was reworked and flipped during a storm event. The occurrence of edrioasteroids in a near shore, perhaps in sub-normal salinity, is unusual for echinoderms. The edrioasteroids show a dispersed spatial distribution and weak thecal orientation. Multiplexidiscus differs from other agelacrinid edrioasteroids in the presence of a complex pattern of ambulacral cover plates combined with nearly straight paedomorphic ambulacra.

Rugose and tabulate corals from the Lower Permian (Wolfcampian) part of the Bird Spring Group in the Providence Mountains, San Bernardino County, southeastern California, comprise eight species in eight genera. Heritschioides mckassoni n. sp. is the lowest stratigraphic record for this index genus on the undoubted shelf of western North America. Paraheritschioides applegatei n. sp. is the first record for the genus in southern California. Neomultithecopora providensis n. sp. is a second species for the genus in the southern Great Basin. The other five species provide close ties to previously described faunas from the Spring Mountains and the Arrow Canyon Range of southwestern and southeastern Nevada. The combined Wolfcampian coral faunas of these three areas are somewhat closer at the genus and species level to the McCloud Limestone Wolfcampian faunas of northern California than to the Wolfcampian shelf faunas in east-central Nevada. Additional species present in the combined faunas are known originally from the Wolfcampian of central Nevada and Kansas and a genus is not otherwise known south of British Columbia. The faunas suggest a subprovince of the Durhaminid Coral Province for the southern California and southern Nevada area and perhaps imply partial isolation from the more northerly parts of the province by land barriers such as the Antler Highlands.

The wall of Michelinia meekana Girty is composed predominantly of lamellae that are approximately parallel to the median dark line, confirming its placement in the genus Michelinia s.s. The presence of a Praemichelinia-type microstructure in some parts of the wall is a recurrence of primitive architecture that suggests derivation of Michelinia from Praemichelinia.

The small, immature brachyopid stereospondyl Platycepsion wilkinsoni from the Early or Middle Triassic of Gosford, New South Wales, is redescribed from a developmental point of view. Whereas the sutural contact between postorbital and parietal suggested by earlier authors cannot be confirmed, a new autapomorphy, the posterior process of the interclavicle with a slightly concave posterior margin, is recognized. A further apomorphic state may be the probable presence of five pairs of ossified ceratobranchials. Soft-tissue preservation of external gills demonstrates that Platycepsion wilkinsoni represents a true larva, forming the first evidence of a larval stage in stereospondyls. Morphology and developmental stage of Platycepsion wilkinsoni indicates that brachyopids conserved the plesiomorphic ontogenetic pattern seen in most Paleozoic temnospondyls, including the early ossification of the dermal skull roof and delayed ossification of the postcranium. The strongly developed ornament, the widened lateral lines, and the well-ossified exoccipitals and stapes suggest an even faster ossification and differentiation of the skull compared to Paleozoic temnospondyls and might represent a general stereospondyl characteristic. In the vertebral column, only the poorly differentiated, still separate neural arches are ossified, whereas the centra remained cartilaginous. This implies that the plesiomorphic pattern of vertebral development was conserved in Mesozoic stereospondyls, irrespective of whether the adult vertebral morphology was rhachitomous, stereospondylous, or diplospondylous. The low degree of ossification of the postcranium, its slow differentiation, and the delayed development of the scapulocoracoid indicate an aquatic mode of life, and the strongly ossified skull and hyobranchial apparatus suggest an emphasis on powerful suction feeding.

A diverse, well-preserved radiolarian assemblage is reported from the Sandbian age Climacograptus bicornis Graptolite Biozone. This new assemblage, recovered from the Pingliang Formation in the Guanzhuang section, China, includes six new species along with 13 other previously described taxa. Geminusphaera new genus incorporates G. grandis n. sp. and G. kongtongensis n. sp. and is proposed for inaniguttids constructed from two distinct porous spheres bearing seven or more primary spines. Protopylentonema new genus is introduced to incorporate pylomate entactinarians with five-rayed initial spicules. It includes P. ordosensis n. sp. as well as P. aperta, P. rimata, and P. insueta that were formerly assigned to Kalimnasphaera. Micro-computed tomography investigation of skeletal microstructure supports establishment of the new genera together with other new spumellarian species: Haplotaeniatum implexa n. sp., Inanigutta quadrispinosa n. sp., and Kalimnasphaera pingliangensis n. sp. It also indicates that family-level reassignment of Etymalbaillella from the Proventocitidae to the Ceratoikiscidae is appropriate.

Global distribution of Late Ordovician radiolarian occurrences highlights a strong preference for areas with equatorial to tropical sea surface temperatures. This must have led to ecological stress among radiolarian communities in adapting to global cooling in the Hirnantian.

UUID: http://zoobank.org/3d3f55b8-0e70-4f9f-9738-265750d8ec3a.

Few bryozoans have been described from the Cretaceous Western Interior Seaway (WIS), which is consistent with the low diversity of other typically stenohaline groups in this large expanse of relatively shallow marine water. Here we describe a new cheilostome bryozoan, Conopeum flumineum n. sp., based on well-preserved material from the Campanian Judith River Formation of the Upper Missouri River Breaks National Monument in north-central Montana. The new species shows strong morphological similarities with Conopeum seurati, a Recent species that is often categorized as brackish, but which is euryhaline and can also be found in marine and stenohaline environments. The new Campanian bryozoan species was found in a locality also containing fragmentary remains of dinosaurs and other terrestrial vertebrates, as well freshwater mollusks and terrestrial plant debris. The sedimentology and facies associations of the fossil-bearing site suggest that the depositional setting was a swamp or tidally influenced fluvial backwater on the Judith River coastal plain. The proximity of the site to the western shoreline of the WIS presumably made it susceptible to occasional marine flooding during storms or extreme tides. Previous occurrences of Conopeum in the Cretaceous of the Western Interior have also been associated with dinosaur remains, corroborating the very nearshore and at times even ‘upstream’ distribution of this euryhaline genus.

UUID: http://zoobank.org/bb1fdc8a-5017-44c5-9251-9e24ef3995e3.

Bryozoans from the Dapingian (Middle Ordovician) of the Baltic paleobasin remain poorly studied and their taxonomic composition is unclear. In this paper, three bryozoan taxa, a bifoliate cystoporate Planopora volkhovensis n. gen. n. sp., a trepostome Hemiphragma insolitum n. sp., and an esthonioporate Esthoniopora clara Koromyslova, are described from Dapingian deposits of an unusual clayey-calcareous Hecker-type mudmound on the right bank of the Volkhov River in Leningrad Oblast’, north-western Russia. Combined X-ray microtomography, scanning electron microscopy, and light microscopy of thin sections were used to characterize their morphology. Analysis of the stratigraphic distribution of early cystoporate bryozoans suggests that Planopora n. gen. is the oldest сystoporate bryozoan with an erect, bifoliate colony. The growth modes of these bryozoans are discussed. The colonies of P. volkhovensis n. gen. n. sp. and E. clara have an attachment structure, a holdfast, at their base, probably indicating their attachment to sponge spicules. The bryozoan H. insolitum n. sp. produced rod-like colonies, formed by overgrowing the problematic tubular fossil Sphenothallus Hall. It can be assumed that sponges with unfused siliceous spicules and individuals of Sphenothallus were numerous on the surface of the mudmound during its formation and provided a suitable substrate for settlement of bryozoan larvae.

UUID: http://zoobank.org/5715872a-8c61-446e-9413-d713fdef1a08

Evidence from the earliest-known crinoids (Tremadocian, Early Ordovician), called protocrinoids, is used to hypothesize initial steps by which elements of the calyx evolved. Protocrinoid calyces are composed of extraxial primary and surrounding secondary plates (both of which have epispires along their sutures) that are unlike those of more crownward fossil and extant crinoids in which equivalent calycinal plating is strongly organized. These reductions inspired several schemes by which to name the plates in these calyces. However, the primary-secondary systems seen in protocrinoids first appeared among Cambrian stem radial echinoderms, with primaries representing centers around which secondaries were sequentially added during ontogeny. Therefore, the protocrinoid calyx represents an intermediate condition between earliest echinoderms and crownward crinoids. Position and ontogeny indicate certain primaries remained as loss of secondaries occurred, resulting in abutting of primaries into the conjoined alternating circlets characteristic of crinoids. This transformative event included suppression of secondary plating and modification or, more commonly, elimination of respiratory structures. These data indicate subradial calyx plate terminology does not correspond with most common usage, but rather, supports an alternative redefinition of these traditional expressions. Extension and adoral growth of fixed rays during calyx ontogeny preceded conjoined primaries in earliest crinoids. Restriction with modification or elimination of calyx respiratory structures also accompanied this modification. Phylogenetic analyses strongly support crinoid origination from early pentaradiate echinoderms, separate from blastozoans. Accordingly, all Tremadocian crinoids express a distinctive aggregate of plesiomorphic and apomorphic commonalities; all branch early within the crinoid clade, separate from traditional subclass-level clades. Nevertheless, each taxon within this assemblage expresses at least one diagnostic apomorphy of camerate, cladid, or disparid clades.

Large palaeotrochid gastropods of the genera Floyda Webster (1905a) and Turbonopsis Grabau and Shimer (1909) occur in the late Frasnian Lime Creek Formation of Iowa. Floyda concentrica was designated as the type species of Floyda by earlier workers (Webster, 1905a; Knight, 1941), but is a junior synonym of F. gigantea (Hall and Whitfield, 1873). Three of five species and subspecies of Floyda described from the Lime Creek (Floyda concentrica, F. concentrica multisinuata, and F. gigantea depressa) are considered synonyms of the type species F. gigantea; the fifth species, F. gigantea hackberryensis, is here reassigned to the closely related genus Turbonopsis. Both F. gigantea and T. hackberryensis are redescribed using the original types and additional hypotype material from the collections of Charles Belanski.

Floyda, first known from late Givetian rocks of the Rhenish Slate Mountains in Germany, is widespread in the United States Midcontinent and western North America by early Late Devonian time. Turbonopsis was endemic to the Appohimchi Subregion of the Eastern Americas Realm prior to the Taghanic Onlap, and appears to have remained so until late Frasnian time when it migrated to western North America.

Eustatic sea-level highstands during the Middle and Late Devonian are thought to have breached barriers to migration, allowing both Floyda and Turbonopsis to disperse by prevailing oceanic currents from the United States Midcontinent into western North America during the late Frasnian. The expected oceanic current patterns of the Middle and Late Devonian paleogeographic reconstructions of Heckel and Witzke (1979, figs. 3, 5) adequately account for the known distribution and dispersal of Devonian palaeotrochid gastropods.

The Palaeotrochidae underwent extinction prior to the latest Frasnian. Floyda, Turbonopsis, and Westerna became extinct during the onset of the last eustatic deepening event prior to the close of the Frasnian. The extinction of the palaeotrochid gastropods as well as other invertebrate groups may have been the result of restriction or near elimination of shallow warm-water, well-oxygenated shelf habitats by the onlap of cold anoxic bottom waters prior to latest Frasnian time.

Fossil insects from the Triassic-Jurassic boundary of England could provide an important resource for investigating the severity of extinction events in the terrestrial realm of the uppermost Triassic. However, the fossil record is poorly understood for this period even though there are abundant historical collections. Many of these collections are still in need of taxonomic revision before they can be used to reconstruct past entomofaunas and make inferences about diversity change through time. This paper is part of a larger project to revise the taxonomy of insects across the Triassic-Jurassic boundary of England to better understand changes in insect diversity through the Triassic-Jurassic boundary and associated extinction period. Herein, the damsel-dragonfly family Liassophlebiidae Tillyard, 1925 is revised and an additional specimen from the Early Jurassic of Antarctica is included. Rossiphlebia new genus is erected for Liassophlebia jacksoni Zeuner, 1962; L. batheri Tillyard, 1925 is considered nomen dubium and another specimen originally attributed to L. batheri is identified as L. withersi Tillyard, 1925. Liassophlebia (?) clavigaster Tillyard, 1925 and L. (?) hopei (Brodie, 1845) are considered incertae sedis at the generic level. Liassophlebia gigantea Zeuner, 1962 is based on a fragmentary specimen but has several unique key characteristics. We redescribe it in Anglophlebia new genus and tentatively in Anglophlebiidae new family in Heterophlebioptera. Also discussed are L. magnifica Tillyard, 1925, L. withersi, and L. pseudomagnifica Whalley, 1985, which are redescribed with updated figures. Caraphlebia antarctica Carpenter, 1969 was originally described from the Early Jurassic of Antarctica as being closely related to Liassophlebia; it is herein confirmed in Selenothemistidae Handlirsch, 1939.

UUID: http://zoobank.org/8fe9a39c-1c3b-4bda-92a6-92c1a0fc95b8

The early astogeny of specimens representing the bryozoan genera Dekayia, Parvohallopora, Heterotrypa, and Homotrypella follows the same pattern documented in other Ordovician trepostomes. After larval settlement and metamorphosis, typically three primary, periancestrular, autozooids bud distally from the founder zooid, the ancestrula, with secondary zooids budding from the primaries, tertiary zooids from the secondaries, and so on. Progressive lateral displacement of buds, through backbudding, eventually produces a subcircular ancestrular disk. Significant intergeneric differences in this basic pattern do not appear to exist. Intrageneric variability in budding pattern occurs during colony development. That variability might have resulted from any or all of the following sources: within-genus plasticity, the development of multiple ancestrulae, or environmental variation. The basic pattern of three primary buds developed from individual ancestrulae has been recognized in other trepostomes, some cyclostomes, and two suborders of cryptostomes. Cladistically, the trait must be considered polyphyletic until more is known about the number of primary buds in the remaining bryozoan suborders. Ancestrular dimensions are statistically similar across genera except between the smaller Dekayia and larger Parvohallopora, but ancestrular sizes in all four Dillsboro genera are consistent with the inference that they possessed a polyembryonic lecithotrophic larval type.

The use of different methodological approaches together with an exhaustive qualitative study has helped to recognize important morphological traits to distinguish species in a systematic and phylogenetic framework. Parabolinella triarthroides Harrington, 1938 was described based on two cranidia from the Quebrada de Coquena, Purmamarca, Jujuy province. The generic assignment of P. triarthroides has been questioned by a phylogenetic analysis, which resolves this species as the sister group of Bienvillia Clark, 1924. To explore the generic assignment of this species, a revision of the type material, plus a morphometric analysis including specimens of Parabolinella Brøgger, 1882 and Bienvillia were performed. In addition, the original matrix used in the published phylogeny was reviewed and enlarged, including more species of Bienvillia. Continuous characters were coded in different ways in order to compare how they could affect the ordering of specimens and their phylogenetic relationships. Finally, both methodologies were compared, especially in regard to the behavior of the quantitative characters included in the analyses. From the combined analyses, it is shown that similarities between the cranidium of P. triarthroides and all other Parabolinella species are true homologies instead of a by-product of evolutionary convergence. Therefore, P. triarthroides should be considered a member of this genus. Finally, this study demonstrates that the best strategy for solving systematic problems in groups where the morphological variation is the only source of information (i.e., fossil taxa without living representatives) is the implementation of an integrative approach, combining different methodological techniques and a good description of specimens.

Two recently collected specimens of Bogotacrinus scheibei Schmidt, 1937, from the Devonian (Emsian–Eifelian) Floresta Formation of Colombia reveal that Bogotacrinus is a dicyclic camerate crinoid genus closely related to Pterinocrinus Goldring, 1923 (Lower–Upper Devonian of eastern North America and western Europe), and Ampurocrinus McIntosh, 1981 (Lower Devonian of Bolivia). The new diplobathrid camerate crinoid family Pterinocrinidae, characterized by species with low conical dicyclic cups and rami composed of compound, bipinnulate brachials, is herein proposed to accommodate these three genera. This family originated in western Europe and migrated into the Malvinokaffric and southern Eastern Americas Realms during the Early Devonian and into the northeastern Appalachian Basin by the Late Devonian.

A tooth battery, palatoquadrate, and a gill-arch element of Bobbodus schaefferi were collected from Late Pennsylvanian/Early Permian (Asselian) rocks near Manhattan, Kansas. Depending on the placement of the Pennsylvanian–Permian boundary, this specimen extends the upper limit of the species from the Virgilian (Gzelian) into the Gearyan (Asselian). The new range thus is Kasimovian to Asselian, a 15 my interval. Based on features of the palatoquadrate, the diagnoses of the order Eugeneodontida and the superfamily Caseodontoidea are revised. Bobbodus is the most primitive genus of the order Eugeneodontida.

A new species of Apiocrinites is described from the Middle Jurassic (Callovian) Matmor Formation of the Negev, Israel. Apiocrinites negevensis is from the tropical latitudes in the Tethys, in contrast to all other reported species of this genus. With a narrow radial facet and adjacent arms not in lateral contact and large aboral cup plates, A. negevensis is quite unusual for this genus.

Rhenopyrgids are rare, turreted edrioasterid edrioasteroids from the lower Paleozoic with a distinctive and apparently conservative morphology. However, new, well-preserved rhenopyrgid edrioasteroid material from Canada, along with a review of described taxa, has revealed broader structural diversity in the oral surface and enabled a re-evaluation of rhenopyrgid functional morphology and paleoecology.

The floor plates in Rhenopyrgus viviani n. sp., R. coronaeformis Rievers, 1961 and, R. flos Klug et al., 2008 are well fused to each other and the interradial oral plate and lack obvious sutures, thereby forming a single compound interradial plate. This differs from other rhenopyrgids where sutures are more apparent. Such fused oral surface construction is only otherwise seen in some derived edrioblastoids and in the cyathocystids, suggesting homoplasy.

Our analysis further suggests that the suboral constriction could contract but the flexible pyrgate zone could not. Thus, specimens apparently lacking a sub-oral constriction should not necessarily be placed in separate genera within the Rhenopyrgidae. It also supports rhenopyrgids as epifaunal mud-stickers with only the bulbous, textured, entire holdfasts (coriaceous sacs) anchored within the substrate rather than as burrow dwellers or encrusters.

Rhenopyrgus viviani n. sp. is described from the Telychian (lower Silurian) Jupiter Formation of Anticosti Island, Québec, Canada and is differentiated by a high degree of morphological variability of pedunculate plates, broader oral plates, and narrower distal ambulacral zones. Specimens lacking or with obscured diagnostic plates from the Ordovician of Montagne Noire, France, and the Ordovician and Silurian of Girvan, Scotland are also described.

UUID: http://zoobank.org/7f81d67f-4155-4719-8a45-b278ad70739d

A new raphistomatinid genus, Wisconsinella, from the Middle Devonian of Wisconsin is described. The type and only known species is Wisconsinella clelandi n. sp. from the Lake Church Formation of late Eifelian age. The new genus is characterized by its highly angular whorl profile and low gradate spire. It is distinguished from all other known raphistomatinid genera by the presence of a narrow, steeply inclined outer whorl surface, demarked both above and below by a sharp, strong angulation.

A low diversity fauna of microscopic crinoids from the Kinderhookian (Mississippian) McCraney Limestone at Seehorn Hollow, western Illinois, is described and illustrated by stereomicrographs. The crinoids include first record of the camerate crinoid genus Hexacrinites (H. mississippiensis n. sp.) above the Devonian. The other three taxa are all inadunates and include the monocyclic microcrinoid Allagecrinus mccraneyensis n. sp., which has up to 14 arms, and two dicyclic poteriocrinoids, Hypselocrinus maccabei (Miller and Gurley, 1894) and an indeterminate genus of the Scytalocrinidae.