Well-preserved polycystine radiolarians, representing a new species in the family Entactiniidae, were recovered from subtidal micrites and bioclastic micrites of the Upper Cambrian (Glyptagnostus reticulatus trilobite zone) Bitiao Formation, western Hunan, China. Confirming earlier, questionable reports of Cambrian Radiolaria, these fossils place the first appearance of the group somewhat before its Ordovician emergence as a principal constituent of the oceanic silica cycle, but long after the Proterozoic diversification of protists.

Nearly continuous cores from a 500-meter interval of upper Moscovian through post-Artinskian carbonate strata on the Finnmark Platform have yielded rich assemblages of fusulinaceans and smaller foraminifers. The fusulinaceans provide an independent time framework for evaluating stratigraphic occurrences of associated smaller foraminifers. Information derived from this study has been integrated with that from previous investigations to produce a smaller foraminiferal biostratigraphic model for the High Arctic. Kasimovian strata are characterized by occurrences of Nodosinelloides spp., Protonodosaria spp. and Hemigordius schlumbergeri. Overlying lower Gzhelian beds are identified by the appearances of Raphconilia modificata and Amphoratheca iniqua. Tezaquina clivuli and Cribrogenerina gigas first occur in upper Gzhelian strata, and Asselian rocks contain appearances of Geinitzina postcarbonica and Pachyphloia spp. Phylogenetic reconstructions suggest that the Late Carboniferous-Early Permian pseudovidalinids (Archaediscacea) derived from the Pseudoammidiscidae, as did the older group of predominantly Early Carboniferous archaediscaceans. The repeated development of similar morphologies within the two groups of archaediscaceans includes examples of both convergence and iterative evolution. The Protonodosariidae and Syzraniidae most likely evolved from an earlandiid ancestor. The syzraniids gave rise to the Geinitzinidae, which in turn gave rise to the Pachyphloiidae. As in the archaediscaceans, evolution within and among the Earlandiidae, Protonodosariidae, Syzraniidae, Geinitzinidae and Pachyphloiidae includes multiple examples of repeated patterns. Two key phenotypic developments seemingly led to bursts of diversification in different groups throughout late Paleozoic foraminiferal evolution. The acquisition of an outer hyaline or pseudofibrous wall layer was a morphologic breakthrough followed by taxonomic radiation in both groups of archaediscaceans and in the Earlandia-Syzrania lineage. The second major event was the shift from an undivided tubular morphology to uniserial morphology in both the Earlandiidae-Protonodosariidae and Syzraniidae-Geinitzinidae lines. Nodosinelloides pinardae is proposed as a new name for Nodosaria grandis Lipina, 1949 (preoccupied).

Analysis of high resolution diversity data for Mississippian corals in the western interior United States yielded mild latitudinal diversity gradients despite the small geographic area covered by samples and a large influence on diversity patterns by geographic sampling intensity (sample bias). Three competing plate tectonic reconstructions were tested using the diversity patterns. Although none could be forcefully rejected, one reconstruction proved less consistent with diversity patterns than the other two and additional coral diversity data from farther north in Canada would better discriminate the two equivalent reconstructions.

Despite the relatively high sampling intensity represented by the analyzed database, diversity patterns were greatly affected by sample abundance and distribution. Hence, some effort at recognizing and accounting for sample bias should be undertaken in any study of latitudinal diversity gradients. Small-scale geographic lumping of sample localities had only small effects on geographic diversity patterns. However, large-scale (e.g., regional) geographic lumping of diversity data may not yield latitudinally sensitive diversity patterns. Temporal changes in coral diversity in this region reflect changes in eustacy, local tectonism, and terrigenous sediment flux, far more than they do shifting latitude. Highest regional diversity occurred during the interval when the studied region occupied the highest latitude. Therefore, diversity data from different regions may not be comparable, in terms of latitudinal inference. Small-scale stratigraphic lumping of the data caused a nearly complete loss of the latitudinal diversity patterns apparent prior to lumping. Hence, the narrowest possible stratigraphic resolution should be maintained in analyzing latitudinal diversity gradients.

Protorthacean brachiopods from the Middle Cambrian of the Moroccan Atlas regions are described in terms of morphology and systematic affinities. The superfamily Protorthacea is revised to include both Protorthidae and Bohemiellidae. Newly introduced is the protorthid genus Saesorthis, the morphologic characteristics as well as the significance of which are discussed in detail together with their bearing on early phylogeny of the Orthacea. A reinvestigation of Brahimorthis antiqua led to the recognition of additional morphologic peculiarities and enhances understanding of its stratigraphic occurrence. Additional descriptions and discussions deal with informally described protorthid and bohemiellid species. Bohemiella and Jamesella are reported from Africa for the first time.

Famatinorthis cf. F. turneri Levy and Nullo, 1973, is an abundant component of a poorly preserved brachiopod assemblage in volcaniclastic rocks at one locality in the Arenig-age Shin Brook Formation in northeastern Maine. The brachiopod assemblage of the Shin Brook Formation has been classed as a Celtic biogeographic assemblage that is interpreted to have lived in cool water at mid- to high peri-Gondwanan latitudes. Famatinorthis turneri sensu stricto is one of the six brachiopod species known from coeval volcanicsrich rocks of continental margin affinities in the Famatina Range of northwestern Argentina; the presence of its congener in Maine supports the Celtic affinities of the Famatina assemblage, but its Ordovician location remains cryptic.

Restudy of Strophomena cornuta Hall, 1843, confirms that it belongs to the superfamily Chonetoidea and establishes its assignment to Strophochonetes within the family Strophochonetidae. This is the first recorded occurrence of the genus in the Silurian of New York, and its late Llandovery age makes S. cornutus (Hall) one of the earliest representatives of the genus.

Basal strata of the Tucumcari Formation south of San Jon, New Mexico, contain a bivalve assemblage different from that of the remainder of the formation. Ceratostreon texanum and two new species herein described (Gyrostrea hinchada, Plicatula quayensis) are the dominant faunal elements of these basal strata. A fourth bivalve, long known as Lopha quadriplicata, ranges downward approximately to the upper limit of C. texanum. However, reevaluation of the taxonomy of this and related species indicates that 1) they have little in common with typical representatives of Lopha and are grouped in a new genus, Peilinia, and 2) specimens from the Tucumcari and related formations formerly assigned to L. quadriplicata are a separate new species, P. levicostata, which appeared in the southern Western Interior before P. quadriplicata appeared in eastern Texas and Oklahoma. The biostratigraphic ranges of several widely distributed bivalves are utilized with ammonite range zones to refine the correlation of several southern Western Interior sequences with the classic lower Washita sequence of Texas and Oklahoma. Because ammonites are rare in the western area, bivalves are locally more important in establishing the age of some exposures. For example, the boundary between or slight overlap of the successive zones of C. texanum and P. levicostata in eastern New Mexico and west-central Texas marks the position of the Craginites serratescens ammonite zone to the east. Strata previously called Kiamichi and Duck Creek in west-central Texas are best considered part of the Tucumcari Formation, representing deposition that occurred mainly earlier than the main Tucumcari sequence in New Mexico.

Two new genera, Barrandecirrus (Porcelliinae) and Pernericirrus (Agnesiinae), from Upper Silurian marine sediments of the Prague Basin (Barrandian area, central Bohemia) are described. Both these genera belong to the family Porcelliidae and represent the oldest representatives of the superfamily Cirroidea (Vetigastropoda). The sinistrally coiled teleoconch of Barrandecirrus filiformis (Perner) suggests that the pseudobilaterally symmetrical teleoconch of the younger genera of Porcelliinae (Porcellia and Coloniacirrus) is a secondary shell character that originated during post-Silurian evolution of this group. In addition, the sinistral, low trochospiral teleoconch of early Agnesiinae [Pernericirrus sinistorsus (Perner) and Agnesia costata (Goldfuss)] as well as the asymmetrical position of the selenizone and the sinistral teleoconch in early Porcelliinae (Barrandecirrus filiformis) support the opinion that both Porcelliinae and Agnesiinae arose from the same stock. Data presented also suggest that the superfamily Cirroidea evolved during the Silurian or earlier, and it has developed parallel to and independently of other larger groups of the Vetigastropoda such as the Pleurotomarioidea and the Trochoidea.

Brachysphingus is a low-spired bucciniform neogastropod known only from the fossil record of California and northern Baja California. The earliest species, Brachysphingus gibbosus Nelson, 1925, ranges in age from latest Cretaceous or possibly earliest Paleocene to the late Paleocene. During the early Paleocene, the smoothish B. gibbosus evolved into the axially ribbed B. sinuatus Gabb, 1869, which is the senior primary synonym of B. gabbi Stewart, 1927. During the late Paleocene, B. sinuatus evolved into B. mammilatus Clark and Woodford, 1927, which is the youngest species of Brachysphingus and which lasted into the early Eocene.

All three species of Brachysphingus were shallow-marine dwellers subject to transport into deeper waters via turbidity currents.

Hystricurids are considered to constitute the earliest (early Ibexian or Tremadocian) family of Proetida, based on comparisons of hystricurid larvae with younger proetide and Cambrian ptychopariide larvae. The hystricurid larvae share a fusiform glabella falling short of the anterior margin with other proetide larvae, which were derived from Cambrian ptychopariide larvae with a forward-expanding glabella. Two discrete morphotypes of hystricurid larvae are recognized. The first type is characterized by the development of a pattern of regularly distributed tubercles on the shield and the presence of a preglabellar field. The second is characterized by the presence of glabellar furrows (discontinuous or transglabellar), an indented posterior margin, and a lack of tuberculation. Each of these hystricurid lineages represented by a distinct larval morphotype is considered ancestral (or sistergroup) to a different group of younger proetides. The second larval morphotype is considered a phylogenetic intermediate between the first type and ptychopariide larvae. Several larval features of these primitive proetides are considered to have originated by early onset of post-larval features of the ptychopariides (peramorphic pattern).

Newly described hystricurid species are Hystricurus n. sp. A, Hystricurus? sp. A, Hystricurus? sp. B, ‘Paraplethopeltis’ n. sp. A, ‘Paraplethopeltis’ sp. B, and Hyperbolochilus cf. marginauctum.

The axial rings of the thorax of seven Ordovician species of Illaenidae, and of the type species of the Silurian Cybantyx, all have the ring curved downward and forward, lacking the articulating furrow but traversed by a stout ventral ridge; the doublure similarly curves downward and forward. This type of axial ring is apparently unique among post-Cambrian trilobites. The axial ring in Scutelluidae is like that occurring in most post-Cambrian trilobites, having a convex ring, deep articulating furrow, and horizontal half ring and doublure. These and many other characters distinguish the Styginidae-Scutelluidae group from Illaenidae. Cybantyx is not an effaced scutelluid, but an illaenid. Upper Cambrian illaenid-like trilobites, which have the illaenid type of thoracic axial ring, deserve consideration as possible ancestors of post-Cambrian illaenids. The thorax is given considerable flexibility by the illaenid axial ring, enabling the body to have been flexed unusually strongly concavely dorsally, as well as to enroll. The musculature suggested omits dorsal longitudinal muscles. It is argued that many illaenids may have been vagrant benthos, particularly adapted for negotiating over irregular surfaces. The view that illaenids lived partly in a burrow is not supported by specimens preserved in such an attitude. The arrangement and varying strength of the terrace ridges on the exoskeleton of Cybantyx is consistent with their having had a sensory function; anastomosing caeca on the fixed cheek and the pleural region of the pygidium are described.

Morphologic variation within and among populations of the common monobathrid camerate crinoid Agaricocrinus was investigated using multivariate and bivariate techniques for samples from 15 localities in the Lower Mississippian (late Osagean) Fort Payne Formation of south-central Kentucky and north-central Tennessee. Despite a wide range of variability, two morphotypes were distinguished at most localities in both autochthonous and allochthonous carbonate facies: Agaricocrinus americanus and the less common A. crassus. Morphologic characters that can be reliably used to separate these taxa include character of the anal area, width of the second primibrachial, and shape of the arm facets. Many other characters of calyx shape and plate proportions used previously for species recognition, such as depth of the basal concavity, height of the interbrachials, height of the tegmen, and number of arms, are widely variable within populations. Variation within species populations is ontogenetic, although a geographic component is recognized within A. crassus. The definition of A. crassus is emended to encompass a broader range of variation than heretofore realized. Eight species previously reported from the Fort Payne Formation are placed in synonymy: A. arcula, A. dissimilis, A. elegans, A. podagricus, A. ponderosus, A. profundus, and A. tugurium are junior synonyms of A. americanus. A. attenuata is a junior synonym of A. crassus.

The study of specimens of the retiolitid graptolites Stomatograptus sp., and Agastograptus robustus with a complete or nearly complete periderm permits a better understanding of the growth and development of retiolitids. Incremental layers deposited in more or less concentric layers on skeletal lists are synchronized with the deposition of sheetlike fusellar bands between the lists. Lists, therefore, become progressively more robust, while the periderm of fusellar bands remain single-layered. It appears that before the development of new distal thecal lists and concomitant deposition of fusellar bands can begin, the next proximal-most thecae must be essentially complete. Retiolitid graptolite thecal growth thus appears to mirror that of “normal” graptolites.

Twelve fused clusters of conodont elements representing the apparatus of Belodina compressa (Branson and Mehl, 1933) were recovered from the Plattin Limestone (Turinian) near New London, Missouri, and Hanover, Iowa. These clusters show that the apparatus of B. compressa consisted of four morphologically distinct elements: eobelodiniform (M), compressiform (S1), grandiform (S2), and dispansiform (S3) elements. All four element types are also present in fused clusters of B. confluens Sweet, 1979, supporting the interpretation that Belodina had a quadrimembrate apparatus. The B. compressa clusters were recovered from pellet-rich wackestones that yielded relatively large and diverse conodont faunas, in which only the elements of B. compressa were fused. The elements of B. compressa present in the fused clusters may have been deposited in fecal pellets, where a higher concentration of calcium phosphate, combined with the relatively large surface area contacts between B. compressa elements, facilitated the fusing of these elements into clusters. These fused clusters provide the basis for interpretation of the apparatus architecture of Belodina.

Several specimens of the Late Cretaceous lamniform shark, Cretoxyrhina mantelli (Agassiz), from the Niobrara Chalk of Kansas suggest that the shark fed on teleosts, mosasaurs, and possibly plesiosaurs. These animals are active vertebrates, so C. mantelli probably occupied the apex of the food chain in the Late Cretaceous seas. This top predator, however, was probably scavenged frequently by anacoracid sharks. Carcharodon carcharias (great white shark) and carcharhinid sharks are considered as the modern guild counterparts for Cretoxyrhina mantelli and anacoracids, respectively.

New material of Gasparinisaura cincosaltensis from the Río Colorado Formation (Upper Cretaceous) of northwestern Patagonia (Río Negro Province, Argentina) provides seven new characters that are interpreted as autapomorphies of the species: 1) four true sacrals; 2) first sacral rib not coalescent with second sacral rib; 3) long pubic peduncle of ilium; 4) absence of anterior intercondylar groove on femur; 5) both malleoli of the tibia approximately at the same level; 6) metatarsal II posteriorly compressed laterally; and 7) low ascendant process of the astragalus. A phylogenetic analysis of selected ornithopods indicates that Gasparinisaura cincosaltensis is the most plesiomorphic Euiguanodontia. A complete absence of hatchlings indicates that Cinco Saltos was not a nest site.

Two species of the enigmatic alga Chaetocladus, C. ruedemanni (new species) and C. dubius (previously regarded as a graptolite incertae sedis), are described from the Silurian Lockport Group of New York and Ontario, Canada, respectively. A comprehensive investigation reveals that these and other Chaetocladus taxa occur in distinctive Konservat-Lagerstätten in association with other thallophytic algae, annelid worms, and lightly sclerotized arthropods. The sedimentology, taphonomy, and biotic composition of Chaetocladus-bearing deposits indicate that this alga thrived in shallow, stagnant, occasionally storm-agitated marine environments. In these settings, preservation of thallophytic algae and associated soft-bodied animals apparently was facilitated by a combination of obrution, anoxia, and early diagenesis of the burial muds.

The morphology of Chaetocladus corresponds to that characteristic of the green alga order Dasycladales, and it is herein referred to this long-ranging taxon as a representative of a new subtribe (Chaetocladinae, new subtribe) within the tribe Salpingoporelleae (emended herein), family Triploporellaceae (emended herein). This euspondyl, endosporate genus extends the range of the euspondyl dasyclads significantly, from the Early Devonian back to the Middle Ordovician, and bridges an evolutionary gap between early Paleozoic aspondyl, endosporate forms and middle Paleozoic euspondyl, cladosporate forms.

Current usage as to the name of the type species of the eurypterid genus Acutiramus Ruedemann, 1935, violates Article 68 of the third edition of the International Code of Zoological Nomenclature (Ride et al., 1985; hereafter referred to as the Code). The history is recorded here, and the correct citation of the type species is given as the conclusion of this note. The pertinent sections of the Code are quoted for convenience of the reader.