Abundant and well-preserved assemblages of disarticulated sponge spicules occur in Middle and Late Cambrian platform carbonates of western Hunan, China. Assemblages recovered from 11 stratigraphic horizons include calcisponges, demosponges, and hexactinellids. Hexactinellida, in particular, are both abundant and diverse in Upper Cambrian carbonates. Comparison with spicule assemblages from Australia indicates that many of these taxa have long stratigraphic ranges, limiting their use in correlation. The morphological diversity of these spicules exceeds that known for living siliceous sponges, supporting the observation that during the Cambrian radiation, sponges, like other metazoans, evolved a variety of architectural forms not observed in later periods. Like conodonts, individual sponges can produce more than one spicule form; thus, an “apparatus genus” concept based on multiple cooccurring elements may eventually prove useful in the biostratigraphic and paleobiological interpretation of disarticulated sponge spicules. Four distinctive forms are recognized as new taxa: Australispongia sinensis new genus and species, Flosculus gracilis new genus and species, Pinnatispongia bengtsoni new genus and species, and Nabaviella paibiensis new species.

Ardmosteges orchamus, new genus, new species, from the Early Pennsylvanian Morrowan sequence in southern Oklahoma, is characterized by a well-developed early aulostegid stage, followed by a fully developed richthofenoid stage. It differs markedly from any previously described genus. The nature of the early development, with a rounded aulostegid shell and a prominent interarea in the ventral valve, suggests that it evolved from the Aulostegidae. The most unique feature of Ardmosteges is that it shows for the first time, a documented mechanism for the addition of new shell material above the hinge area in the ventral valve in shells that proceeded to develop a richthofenoid cone. Shell layers were extended posteriorly from the margins of the ventral valve onto the interarea of that valve indicating that the mantle grew onto the hinge area from each side. This irregular and asymmetrical process gradually filled the space above the hinge and was followed by the upward growth of a typical richthofenoid cone. In the proposed development of the Permian richthofenoids from Ardmosteges it is postulated that the characteristic interarea of Ardmosteges was suppressed during extreme development of a distinctly cylindrical cone.

Ardmosteges provides the missing link between the Aulostegidae and the Richthofenoidea. Its characters are primitive compared to those of the Permian richthofenoids but it is similar in having a deeply recessed opercular dorsal valve, protective spines in the vestibule above the dorsal valve, and in being attached by rhizoid spines.

Lower to Middle Cambrian shales of the Mount Cap Formation in the Mackenzie Mountains, northwestern Canada, host a variety of Burgess Shale-type macrofossils, including anomalocarid claws, several taxa of bivalved arthropod, articulated hyolithids, and articulated chancelloriids. Hydrofluoric acid processing has also yielded a broad range of organic-walled fossils, most of which are derived from forms more typically known as shelly fossils; e.g., trilobites, inarticulate brachiopods, small shelly fossils (SSF), hyolithids, and chancelloriids. Organic-walled hyolithids include conchs, opercula and helens; the proximal articulation of the helens is erosive, suggesting that they were formed “instantaneously” and periodically replaced. Organic-walled chancelloriid sclerites exhibit a polygonal surface texture and an inner “pith” of dark granular material with distally oriented conoidal divisions; such a pattern is similar to that seen in the fibers of some modern horny sponges and points to a poriferan relationship for the chancelloriids. The robust nature but minimal relief of most of these fossils suggests that primary biomineralization was minimal.

The new farreid hexactinellid sponge Hormathospongia dictyota new genus and new species, is described from the upper Santonian Dobbins Shale Member of the Forbes Formation of the Upper Cretaceous Great Valley Sequence from the west side of the Sacramento Valley, northwest of Sacramento. The relatively simple skeleton is composed of quadrangularly arranged hexactines with overlapping rays, an arrangement strikingly similar to the skeletal structure of early Paleozoic reticulosid hexactinellids. However, the California Cretaceous sponges clearly show those spicules embedded in siliceous beams that are united to form a solid dictyonal skeletal framework of only a single layer of regular mesh. Such an occurrence and stratigraphic relationships suggests that the dictyonine sponges had their origin from the simply spiculed reticulosid hexactinellids rather than from the more complex dictyosponges.

Disarticulated spines and sclerites of assumed multiple row problematic organisms are present in several Mississippian and Pennsylvanian stratigraphic units. Marginal spines and dorsal spinose sclerites are present. Marginal sclerites are distinguishable into anterior, posterior, and left- and right-handed lateral forms. The new family Aenigmatectidae and genus Aenigmatectus with two new species, A. hystricosus and A. magnacavus, are recognized. Aenigmatectus sp. from the Mississippian is also described. The family is tentatively assigned to the order Hercolepadida Dzik, 1986.

Supposed Upper Proterozoic strata in the southwest Taoudeni Basin, Guinea and Senegal, and from the Mauritanide fold belt, Mauritania, have yielded mostly poorly preserved small skeletal fossils of metazoan and protistan origin. Problematic, but possible echinoderm material and spicules of the heteractinid sponge Eiffelia dominate the Taoudeni Basin assemblage. The age of the material is not certain but the paleontologic data suggest an Early Cambrian age for the stratigraphically lowest faunas, and a Middle Cambrian age is possible for the stratigraphically highest collections.

Several specimens of the large, discoidal, new inozoid genus and species, Gigantospongia discoforma, have been discovered in the Upper Permian, Upper Capitan Limestone in the northern Guadalupe Mountains of New Mexico, near Carlsbad Caverns. The holotype is nearly 2.5 meters across, as exposed, and ranges from 8-20 mm thick, with numerous canals transverse and parallel to the principal plane. These canals are approximately 1 mm in diameter and separated by tracts 1-2 mm thick. Thickened dermal and gastral layers, each approximately 1 mm thick, occur at tops and bases of both the holotype and associated paratypes in the “Sponge Window” exposures of Bat Cave Draw, and in specimens from Chinaberry and Hackberry Draws. Inverted Lemonea conica Senowbari-Daryan, 1990, is apparently attached to the base, and appears to have grown inverted in a void formed or capped by the tabular inozoid. Well-preserved specimens of Amblysiphonella also appear inverted, as do examples of Lemonea cylindrica (Girty, 1908), a new species of Lemonea, and Guadalupia explanata (King, 1943), which occur between the holotype and an underlying paratype. All appear coated with Archaeolithoporella crusts. Microstructure of the inozoan skeleton is obscured by diagenesis.

A limited fauna of relatively simple, thin-walled, hexactinellid sponges, including moderately coarse-textured, funnellike Hexactinella(?) conica new species, fine-textured, tubular to branched Hexactinella(?) tubula new species, fragments of delicate Eurete goederti(?) Rigby and Jenkins, 1983, and Farrea(?) species, has been found in the Oligocene Lincoln Creek Formation on Canyon River, in the southcentral part of the Olympic Peninsula, Washington. These sponges dominate a chemosynthetic invertebrate assemblage that included the gastropod Provanna antigua Squires, 1995; the polyplacophoran Leptochiton alveolus (Lovén, 1846), and radiolarians. Most of the sponges are preserved as silica in a localized cherty and botryoidal, calcareous cement-filled limestone formed at bathyal depths by bacterial oxidation of methane at a cold seep. This is the third known report of sponges from ancient chemosynthetic deposits.

The genus Tribrachiatus (all species of which are widely used stratigraphic markers) and its related genus Rhomboaster are studied in type samples and in five DSDP/ODP sites that have magnetostratigraphies and range from low through high latitudes. Rhomboaster calcitrapa, R. spineus, and R. bitrifida are shown to be junior synonyms of R. cuspis. Rhomboaster transforms into T. bramlettei by flattening of the nannolith. This makes the location of the first occurrence (FO) of T. bramlettei difficult and imprecise. The FO of Rhomboaster, however, is less ambiguous and more reliable for global stratigraphic correlation. Tribrachiatus contortus has a very short (< 1 m.y.) and consistent stratigraphic range. The FO of T. orthostylus is located very near the top of Chron C24r and slightly below the last occurrence of T. contortus. This study also presents detailed morphometric data on the changes from T. bramlettei to T. contortus to T. orthostylus, and calibrates their changes through time with magnetostratigraphy. This shows a detailed picture of the progressive evolution in this group as well as offers an age curve for high-resolution stratigraphic correlation.

Heliolitine corals are closely associated with lithistid sponge-dominated reef mounds in Ludlow carbonate ramp facies on Somerset Island. The corals occur abundantly in argillaceous, fossiliferous wackestone immediately flanking and capping the reef mounds, less commonly in calcilutite mudstone within the reef mounds, and with sharply decreasing abundance in nodular argillaceous wackestone to mudstone away from the reef mounds. Exhaustive field collection, and systematic study that included biometric analysis of collected assemblages, indicates that ten heliolitine species are present, including the new species Heliolites furyi, H. garnieri, and H. greineri, and two unidentified species, Heliolites sp. A, and Podollites? sp. The occurrence of H. subdecipiens Klaamann, 1984, H. tchernyshevi Bondarenko, 1966, H. cf. H. rariformis Tchi, 1976, Stelliporella cf. S. podolica Bondarenko, 1971, and Squameolites anomalus Tchi, 1976 indicates an affinity with Eurasian rather than North American faunas of equivalent age. Many new species have been ascribed to Stelliporella since the mid-1970s; most lack the diagnostic axial structures of the genus and are more appropriately regarded as belonging to Heliolites. Newly defined structures termed septal florets occur commonly in H. garnieri and very rarely in three other species of Heliolites. Effective taxonomic use of septal development requires very careful study because of the degree of intraspecific and intracolony variation in some species.

Restudy of upper Pliocene (ca. 2.4-1.8 Ma) and possible lower Pleistocene dinoflagellates from the Royal Society borehole at Ludham, eastern England has revealed the presence of more than 29 dinoflagellate species, substantially revising earlier records of this important locality. Assemblages reflect climates that fluctuated within a warm- or mild-temperate to cool range, as shown by the discovery that specimens earlier assigned to the warm-water Tectatodinium pellitum all belong to a cool-water element comprising Bitectatodinium tepikiense, Filisphaera filifera, F. microornata, and Habibacysta tectata. This element appears to have been widely mistaken for Tectatodinium pellitum in coeval deposits of the North Sea basin and beyond. The following are among several species reported for the first time from coeval deposits of the North Sea basin: Filisphaera filifera, F. microornata, Operculodinium? eirikianum, O. giganteum, Spiniferites ludhamensis n. sp., S. rubinus, and Trinovantedinium glorianum. The dinoflagellate Spiniferites ludhamensis n. sp. and acritarch Nannobarbophora walldalei n. sp. are formally described.

New fossils from the Neoproterozoic Ediacara fauna of South Australia are interpreted as the oldest known hexactinellid sponges. They occur within the Ediacara Member of the Rawnsley Quartzite (Pound Subgroup) from several locations in the Flinders Ranges. The new genus, Palaeophragmodictya, is characterized by disc-shaped impressions preserving characteristic spicular networks and is reconstructed as a convex sponge with a peripheral frill and an oscular disc at the apex.

Continental slope facies in eastern New York have the most diverse small shelly faunas known in Laurentian late Early Cambrian strata. Diversity of a lower Elliptocephala asaphoides assemblage, the oldest body fauna in the Taconic allochthon, reflects turbidity current exhumation, transport, and deposition of phosphatized fossil hash in a proximal facies of the Browns Pond Formation. Phosphatization is linked to the first of two Olenellus Chron intervals with a thickened dysaerobic water mass on the slope. This interval of increased rate of sea-level rise corresponds to development of extensive carbonate belts and onlap of dark shales (e.g., Forteau and lower Kinzers formations) on the east Laurentian shelf.

The assemblage includes two trilobites, archaeocyathan fragments, echinoderm debris, the first edrioasteriod from east Laurentia, and 26 small shelly fossil species. New taxa are Asperconella new genus and Stenotheca taconica new species (helcionellids); Mackinnonia obliqua new species (pararostroconch); Conotheca laurentiensis new species, Insolitotheca new genus, and Petasotheca minuta new genus and species (hyoliths); and Plinthokonion? psamminon new species (agglutinated problematicum).

A Lower Silurian (Llandovery) shelly fauna is described; the first from the Iberian Peninsula. It is dated as late Llandovery (early Telychian) by Stricklandia aff. laevis and is overlain by a late Telychian conodont fauna. The fauna is from the volcaniclastic El Castro Formation, Viodo Limestone Member, north of Viodo, Asturias, northern Spain. There are seven common and five rarer brachiopods, including the new taxa Asturorthis sarreoensis new genus and species, Mendacella cantabrica new species, Katastrophomena truyolsi new species, Viodostrophia alcaldei new genus and species, Stegerhynchus juliverti new species, and Fenestrirostra? viodoensis new species.

Well-preserved, laterally flattened, farreid hexactinellid sponges of the new species Farrea rugosa have been recently discovered in the upper Miocene Puente Shale in the Peralta Hills in southeastern Anaheim, Orange County, California. This is the first farreid sponge reported from the Miocene of California and is one of the few Miocene sponges reported from North America. The cluster is of upward bifurcating, moderately complex sponges in which branches are regularly rugose and skeletons are each a single layer of dictyid net, with aborted proximal and distal rays in the otherwise laterally fused quadruled skeleton of original silica. The sponges occur in pinkish brown sandy siltstone in the limited exposure beneath older alluvium that blankets much of the local area.

Twenty-two taxa of stromatoporoids are described from the outcrop belt of the Elm Point, Winnipegosis, Dawson Bay, and Souris River Formations in Manitoba. The Elm Point Formation contains a fauna of stromatoporellids of Eifelian age that is characterized by the new species, Stromatoporella manitobaensis. The Winnipegosis stromatoporoids are dolomitized but the widespread species Actinostroma tyrrelli, Taleastroma logansportense and the new species Trupetostroma imbrex can be recognized in this Givetian assemblage. The Dawson Bay fauna is characterized by the appearance of the dendroid forms, Stachyodes and Dendrostroma and species of Hermatostroma, Trupetostroma, and Parallelopora. A species of Actinostroma, comparable to A. filitextum is the most abundant stromatoporoid in the Dawson Bay Formation. The Souris River fauna, referred to as the Arctostroma contextum assemblage, is widespread at the Givetian-Frasnian boundary. Elements occur elsewhere in western Canada in the Beaverhill Lake, Waterways, lower Duperow and lower Fairholme units. Stromatoporoids in these four assemblages are relatively restricted in their stratigraphic occurrence and sufficiently widespread in their distribution to be useful in correlation.