New morphological features of the mobergellan Discinella micans (Billings, 1871) from the lower Cambrian (Stage 4) of Northeast Greenland and southern Labrador are described. The new features include: (1) the morphology of the larval shell, which is shown to be cap-shaped, subcircular, and with impressions of the internal muscle attachment scars; (2) a range of unusual shell deformations (changes in growth direction resulting in thickened shells, partial detachment of shell laminae and subsequent regrowth, internal projections of shell material increasing the depth of the shell by up to 150%, disturbances and irregular fusion of muscle scars). In addition, we provide new details about the variability in number and shape of the anteriormost internal muscle scars, which often fuse and may vary in number from one to three (resulting in nine to 11 scars in total). Together the new observations provide additional strength for the hypothesis that mobergellan shells represent opercula of an as yet unknown tubular organism.

Plesiosaurs and mosasaurs are identified from the Puskwaskau Formation of west-central Alberta, Canada. These deposits record the final stages during which the Western Interior Seaway remained open to the Boreal Sea to the North and therefore are important for determining the ranges of high-latitude marine reptiles. Polycotylid and elasmosaurid plesiosaurs shared these waters with russellosaurine (including plioplatecarpine) mosasaurs suggesting a diverse ecology of large-bodied marine predators occupied these high-latitude waters in the early Campanian. This locality, situated at 65°N paleolatitude, helps link the poorly known faunas from northern Canada with the better-known faunas from central and southern North America. Rare articulated material from the Puskwaskau Formation urges further investigation of this poorly explored unit.

This work provides the detailed investigation (taxonomy, biostratigraphy, and paleoecology) of a nonmarine ostracod fauna from the Shinekhudag Formation in Gobi–Altai area, southwest Mongolia. The samples from two sections (Tsagaan Tsuvarga and Oshih Hollow East) yielded various ostracods assigned to nine species belonging to six genera: Cypridea verrucata Neustrueva, 1974, C. ihsienensis Hou, 1958, C. unicostata Galeeva, 1955, C. tumefacta Neustrueva, 1974, Yumenia cf. Y. oriformis Hou, 1958, Scabriculocypris subscalara Zhang and Chen in Ye et al., 2003, ?Trapezoidella sp., Candona sp., and Vlakomia ulanense Neustrueva, 1977. The biostratigraphic application of our taxonomic results suggests that the age of the Shinekhudag Formation is Barremian–Aptian. In addition, the ostracod fauna shows strong affinities to faunas from northeast China and potentially northwest China, providing evidence of faunal exchanges between these regions and southwest Mongolia. The new discovery of Vlakomia ulanense indicates that mid-Cretaceous (Albian) species in northeast China probably originated in Mongolia at the time of deposition of the Shinekhudag Formation. Two ostracod assemblages in the studied sections reflect that different paleoenvironment settings have existed during deposition; the Tsagaan Tsuvarga Section represents a shallow-littoral zone of athalassic (inland) saline lake under arid climate, and the dominance of cypridoideans of the Oshih Hollow East Section is indicative of ephemeral water bodies.

An example of parasitic drilling in a rhynchonelliform brachiopod is described from the Shiyanhe Formation (Katian, Upper Ordovician) of Henan, central China. The boring extends into the shell almost perpendicular to the surface. The shell has been serially sectioned, and the trace (including boring and bioclaustration) has been modeled in three dimensions. Healing of the shell evident in serial sections supports a long-term relationship between the brachiopod and borer that we interpret as parasitic. Platyceratid gastropods, found at the same locality as these brachiopods, are the most likely drilling organism. Previous reports of Paleozoic brachiopod parasitic traces can be classified into two main groups, constructive association and destructive association, depending on whether parasites damage brachiopod shells. The example in this study belongs to the second type as the brachiopod shell has been partly damaged by the borer.

The utility of benthic foraminifera in bathymetric interpretation of clastic depositional environments is well established. In contrast, bathymetric distribution of benthic foraminifera in deep-water carbonate environments has been largely neglected. Approximately 260 species and morphotypes of benthic foraminifera were identified from 12 piston core tops and grab samples collected along two traverses 25 km apart across the northern windward margin of Little Bahama Bank at depths of 275-1,135 m. Certain species and operational taxonomic groups of benthic foraminifera correspond to major near-surface sedimentary facies of the windward margin of Little Bahama Bank and serve as reliable depth indicators. Globocassidulina subglobosa, Cibicides rugosus, and Cibicides wuellerstorfi are all reliable depth indicators, being most abundant at depths >1,000 m, and are found in lower slope periplatform aprons, which are primarily comprised of sediment gravity flows. Reef-dwelling peneroplids and soritids (suborder Miliolina) and rotaliines (suborder Rotaliina) are most abundant at depths <300 m, reflecting downslope bottom transport in proximity to bank-margin reefs. Small miliolines, rosalinids, and discorbids are abundant in periplatform ooze at depths <300 m and are winnowed from the carbonate platform. Increased variation in assemblage diversity below 900 m reflects mixing of shallow- and deep-water species by sediment gravity flows.

The enigmatic tabulate genus Palaeacis is composed primarily of species with wedge-shaped coralla. Palaeacis walcotti Moore and Jeffords, 1945, P. kingi Jeffords, 1955, and P. cf. P. walcotti, described below from the Morrowan (Pennsylvanian) Golf Course Formation of the Ardmore Basin, south-central Oklahoma, represent a distinctive morphogroup characterized by a discoid corallum. Discoid Palaeacis ranges from the Morrowan to the Missourian and, so far, is known only from the mid-continent region of North America. The discoid shape, combined with concentric skeletal accretion, large corallite diameters, complex calice floors, and porous skeleton suggest, based on comparisons with the functional morphology of recent scleractinians, that these corals were well suited to an auto-mobile (vagile) life strategy, much as are many Recent fungiid corals. Discoid Palaeacis inhabited environments with muddy or sandy, unconsolidated substrates and was associated with low-diversity, nonencrusting faunas. This association is consistent with an auto-mobile life strategy. Auto-mobility in Palaeacis would represent the first such reported occurrence in the Tabulata, and the first in Paleozoic colonial corals of all types.

I want to begin by thanking you for giving me the opportunity to serve as President of The Paleontological Society and especially for the boundless cooperation I have received from you, the members. Few scientific societies work as well as The Paleontological Society. Some societies function because of the dedication of a few fully committed members. Others rely on paid, professional staff to conduct the society's business. In contrast, the success of The Paleontological Society stems from the day-to-day enthusiasm for our roles and goals that is distributed uniformly across the membership. Holding this office has been a high privilege, and I am grateful to you for having selected me.

Modular coral-like fossils from Lower Ordovician (Tremadocian) thrombolitic mounds in the St. George Group of western Newfoundland were initially identified as Lichenaria and thought to include the earliest tabulate corals. They are here assigned to Amsassia terranovensis n. sp. and Amsassia? sp. A from the Watts Bight Formation, and A. diversa n. sp. and Amsassia? sp. B from the overlying Boat Harbour Formation. Amsassia terranovensis n. sp. and A. argentina from the Argentine Precordillera are the earliest representatives of the genus. Amsassia is considered to be a calcareous alga, possibly representing an extinct group of green algae. The genus originated and began to disperse in the Tremadocian, during the onset of the Great Ordovician Biodiversification Event, on the southern margin of Laurentia and the Cuyania Terrane. It inhabited small, shallow-marine reefal mounds constructed in association with microbes. The paleogeographic range of Amsassia expanded in the Middle Ordovician (Darriwilian) to include the Sino-Korean Block, as well as Laurentia, and its environmental range expanded to include non-reefal, open- and restricted-marine settings. Amsassia attained its greatest diversity and paleogeographic extent in the Late Ordovician (Sandbian–Katian), during the culmination of the Great Ordovician Biodiversification Event. Its range included the South China Block, Tarim Block, Kazakhstan, and Siberia, as well as the Sino-Korean Block and Laurentia, and its affinity for small microbial mounds continued during that time. In the latest Ordovician (Hirnantian), the diversity of Amsassia was reduced, its distribution was restricted to non-reefal environments in South China, and it finally disappeared during the end-Ordovician mass extinction.

UUID: http://zoobank.org/ef0abb69-10a6-46de-8c78-d6ec7de185fe

This paper describes Byzantia obliqua, new genus and species. Byzantia is a small, distinctively ornamented, gastropod genus from the middle Permian (Leonardian-Guadalupian) of West Texas. This provides further evidence of the diversity of the Neritacea in the middle Permian and of the diverse endemic fauna of west Texas.

Paleoecological analysis of three attached spiriferid species (Punctospirifer kentuckyensis, Crurithyris planoconvexa, and Hustedia mormoni) and six free-living chonetid brachiopod species (Chonetinella flemingi, Chonetinella verneuiliana, Lissochonetes geinitzianus, Mesolobus mesolobus, Neochonetes fragilis, and Quadrochonetes geronticus) from Middle and Upper Pennsylvanian strata of north-central Texas has been undertaken using, in part, population dynamics information derived initially from size-frequency distributions. The brachiopod populations in this study are believed to represent in situ assemblages formed by noncatastrophic mortality. Spiriferid species occurred in large populations characterized by positively skewed size-frequency distributions in which few individuals attained the maximum potential size reported for a given species. Chonetid species, in contrast, occurred in smaller numbers characterized by negatively to low positively skewed size-frequency distributions in which greater numbers of individuals attained maximum potential size.

The differences observed in the population structure of these two groups can best be explained as reflecting different adaptive lifestyle strategies that are shared at the ordinal level. Morphological features common to chonetid species enabled individuals to live freely at the sediment-water interface and perhaps reorient their position if disturbed. Based on size-frequency analysis, low-density populations of chonetids appear to produce relatively larger numbers of survivors in the adult and maximum size classes. Spiriferids were constrained to attachment surfaces occupied at the time of larval settlement, and individuals presumably had no mechanism to regain life position if overturned or if this surface became unstable. These physical limitations seem to be reflected in a population structure in which higher density populations were required to overcome the high mortality rates incurred by individuals. This appears to be a case in which size-frequency distributions have not been significantly altered by taphonomic overprint and in which size-frequency analysis can be used to detect differences in the life histories and population structure of brachiopod species.

The eodiscina comprises small, isopygous trilobites with either two or three thoracic segments. Small eyes may be present, but several genera and species lack visual organs. Eodiscoids are characteristic elements of many Cambrian faunas and are important for correlations of upper Lower Cambrian and lower Middle Cambrian strata (e.g., Robison et al., 1977; Ahlberg and Bergström, 1993; Geyer and Shergold, 2000; Fletcher, 2003).

Problematic phosphatic elements are reported for the first time from Bohemia, Czech Republic, and are attributed to Eurytholia bohemica n. sp. Similar mineralized elements, interpreted as sclerites, were known only in a very narrow interval from Middle-Late Ordovician beds bordering the Iapetus Ocean. This new report comes from the Silurian and Early Devonian and provides a significant range extension for these Problematica as well as an enlargement of their geographic extent. Comments open new perspectives in the interpretation of these elements.

The first-described articulated Silurian sponges from Spain and Portugal include a moderate assemblage of hexactinellids and a single monaxonid demosponge. The sponges were collected from a thin layer at the top of the Cyrtograptus lundgreni-Monograptus testis graptolite biozone, in a possible volcanic ash of latest Homerian (Wenlock) age. The sponges are from southeastern Portugal and southwestern Spain in the Ossa-Morena Zone of the Hesperian Massif. The hexactinellid collection includes several specimens of the new species, Protospongia iberica, and fragments of Diagoniella species and Gabelia(?) sp. Specimens of the latter two taxa are too small for species identification. Demosponges are represented by a single described specimen of a probably new genus and species preserved as a “wreath” of monaxon spicules. Dermal and gastral layers are of very fine spicules developed over the moderately coarse, aligned, principal body spicules.

The new balanid subfamily Concavinae is based on the genus Concavus Newman, 1982, and includes five genera and 29 species-group taxa. The subgenera Concavus, Tamiosoma Conrad, 1856 (senior synonym of Menesiniella Newman, 1982), and Arossia Newman, 1982, are raised to generic rank. Two new genera, Chesaconcavus (type species Balanus concavus chesapeakensis Pilsbry, 1916) and Paraconcavus (type species Balanus concavus pacificus Pilsbry, 1916), are proposed, based on fossil and extant species from North America. New species include Tamiosoma advena from the Pliocene of southern Florida, Chesaconcavus rossi and C. santamaria from the middle Miocene of Maryland, C. myosulcatus from the upper Miocene of Virginia, Arossia newmani from the middle Miocene of Maryland, A. rubra from the upper Miocene of central California, A. aurae from the lower Pliocene of North Carolina, and Paraconcavus margaritanus from the upper Miocene of southern California. Concavines, a predominantly Northern Hemisphere group, appear in the late Oligocene in North America and Europe, diversify and spread rapidly in the Neogene, and, with the exception of a few eastern Pacific relicts, become extinct before the late Pleistocene.

Dictyosponges from the Chesteran Bangor Limestone document the first known occurrence of these hexactinellids in Mississippian rocks of Alabama and their discovery adds information to the worldwide impoverished record of Lower Carboniferous Porifera. The sponges are generally fragmented and occur in marine, cross-bedded, sandy limestone and sandstone channel-fill lenses that occur up to 12 m above the base of the formation, above the Hartselle Sandstone. The reticulosid dictyosponges Dictyospongia(?) sp., Clathrospongia bangorensis n. sp., Clathrospongia(?) sp. A, Clathrospongia(?) sp. B, Thamnodictya(?) radiata n. sp., and Phragmodictya rugosa n. sp. are described. Previously, the lyssacinosid(?) hexactinellid Pileospongia lopados Rigby, Keyes, and Horowitz, 1979, was described from this region, from the slightly older Chesteran Monteagle Limestone, and its occurrence in the Bangor Limestone is the youngest yet discovered. In addition to the above hexactinellids, the demosponge Belemnospongia parmula Rigby, Keyes, and Horowitz, 1979, is questionably represented by a single impression in fine-grained sandstone of the Bangor Limestone.

The Edaphosauridae is an important family of primitive synapsids that includes the oldest known terrestrial herbivorous vertebrates. Until the recent description of a new, primitive edaphosaur from the Upper Pennsylvanian of Kansas (Reisz and Berman, 1986), the herbivorous Edaphosaurus was the only known member of the family. Accordingly, fragmentary edaphosaurid materials from Europe and North America had been assigned to Edaphosaurus on the basis of the characteristic neural spine morphology.

The record of the fossil representatives of the family Juliidae is updated. The new genus Candinia is proposed, in the subfamily Juliinae, for two fossil species somewhat intermediate between Julia and Berthelinia. The new species Candinia pliocaenica is recorded from the lower Pliocene shallow marine deposits near Siena (Tuscany, Italy). This is the first record of Sacoglossa in the Mediterranean Basin. Based on the very specialized life habits of the Juliidae, it is suggested that subtropical Caulerpa algal prairies inhabited the Mediterranean during the early Pliocene, likely becoming extinct in this basin because of the mid-Pliocene climatic deterioration.

The tectonic evolution of the Sibumasu Block during the Permian remains controversial, and Permian faunas and their paleobiogeographic affinities provide some insight into its paleogeographic and tectonic evolutionary histories. In this paper, a new brachiopod fauna dominated by Spinomartinia prolifica Waterhouse, 1981 is described from the uppermost part of the Taungnyo Group in the Zwekabin Range, eastern Myanmar. This brachiopod fauna includes 23 species and its age is well constrained as late Kungurian by the associated conodonts, i.e., Vjalovognathus nicolli Yuan et al., 2016 and Mesogondolella idahoensis (Youngquist, Hawley, and Miller, 1951), contrary to the late Sakmarian age given to the same brachiopod faunas previously reported from southern Thailand and Malaysia. Based on comprehensive comparisons of the Cisuralian brachiopod faunas and other data in different parts of the Sibumasu Block, we consider that they are better subdivided into two independent stratigraphic assemblages, i.e., the lower (earlier) Bandoproductus monticulus-Spirelytha petaliformis Assemblage of a Sakmarian to probably early Artinskian age, and the upper (younger) Spinomartinia prolifica-Retimarginifera alata Assemblage of a late Kungurian age. The former assemblage is a typical cold-water fauna, mainly composed of Gondwanan-type genera, e.g., Bandoproductus Jin and Sun, 1981, Spirelytha Fredericks, 1924, and Sulciplica Waterhouse, 1968. The latter assemblage is strongly characterized by an admixture of both Cathaysian and Gondwanan elements, as well as some genera restricted to the Cimmerian continents. Notably, the spatial distribution pattern of these two separate brachiopod assemblages varies distinctly. The Sakmarian cold-water brachiopod faunas have been found in association with glacial-marine diamictites throughout the Sibumasu Block including both the Irrawaddy and Sibuma blocks. In contrast, the Kungurian biogeographically mixed brachiopod faunas are only recorded in the Irrawaddy Block, unlike the Sibuma Block that contains a contemporaneous paleotropical Tethyan fusuline fauna. Thus, it appears likely that by the end of Cisuralian (early Permian), the Sibumasu Block comprised the Irrawaddy Block in the south with cool climatic conditions, and the Sibuma Block in the north with a temperate to warm-water environment, separated by the incipient Thai-Myanmar Mesotethys.

The morphologic expression of microenvironmental variation is difficult to document in fossil ecosystems and therefore is poorly understood. However, documentation of environmental sources of variation in the phenotype is essential for meaningful studies of microevolution and speciation. A fossil assemblage from the Mississippian (Valmeyeran) Warsaw Formation near St. Louis, Missouri, provides necessary conditions to evaluate microenvironmentally induced phenotypic variation in the Paleozoic trepostome bryozoan Leioclema punctatum (Hall, 1858). Specimens of L. punctatum, found as fragments in 22 discrete piles, were collected in their entirety from a weathered surface. Each pile contained 20—200+ branch fragments of L. punctatum, which were all originally attached to large, soft-bodied hosts (sponges?). Multiple attachment bases were found in most piles, indicating that 1) multiple L. punctatum colonies (genotypes) are represented in each pile, and 2) each pile represents a near contemporaneous, relatively short-lived microcommunity. Morphological characters were measured (four per section) from two branches for each of two specimens from five separate piles. Results from completely random, nested, one-way ANOVA indicate that no highly significant differences exist among microcommunities or between colonies for any measured characters, but that significant variation exists within colonies and among colonies in the same microcommunity (pile). That is, submicroenvironmental variation, within and among colonies, can play a greater role in morphogenesis than environmental heterogeneity within a given environmental setting (undifferentiated facies). Microenvironmental factors affect the size and shape of mesopores (space-filling structures) more than other morphological characters.

Results are encouraging for the general application of the preserved fossil phenotypes as proxies for biological species. This conclusion is based on the absence of systematic variation at microenvironmental levels, measurable here, but not normally distinguishable in paleontological and sedimentological studies. Correct attribution of fossil species assumes, however, that the source and the relative importance of the low-level (submicroenvironmental) variation on development/ontogeny is recognized and attributed appropriately. Results call for a reevaluation of the application of within versus among colony variation used as a proxy for environmental stability.