Carbonates and rare shales of the ca 700–800 Ma old Draken Conglomerate Formation, northeastern Spitsbergen, preserve a record of environmental variation within a Neoproterozoic tidal flat/lagoon complex. Forty-two microfossil taxa have been recognized in Draken rocks, and of these, 39 can be characterized in terms of their paleoenvironmental distributions along a gradient from the supratidal zone to permanently submerged lagoons. Supratidal to subtidal trends include: increasing microbenthic diversity, increasing abundance and diversity of included allochthonous (presumably planktonic) elements, decreasing sheath thickness of mat-building organisms (with significant taphonomic consequences), and an increasing sediment/fossil ratio in fossiliferous rocks. Five principal and several minor biofacies can be distinguished. The paleoecological resolution obtainable in the Draken Conglomerate Formation rivals that achieved for most Phanerozoic fossil deposits. It documents the complexity and diversity of Proterozoic coastal ecosystems and indicates that both environment and taphonomy need to be taken into explicit consideration in attempts to understand evolutionary trends in the early fossil record. Three species, Coniunctiophycus majorinum, Myxococcoides distola, and M. chlorelloidea, are described as new; Siphonophycus robustum, Siphonophycus septatum, and Gorgonisphaeridium maximum are proposed as new combinations.

Latest Precambrian through Early Cambrian tectonic history and stratigraphy are comparable in southeastern Cape Breton Island and the western Placentia–Bonavista axis, southeastern Newfoundland. The lithostratigraphic nomenclature of southeastern Newfoundland is used for this interval in Cape Breton Island. Upper Precambrian volcanic rocks of the Forchu Group (=“Giant Lake Complex,’ designation abandoned) are unconformably overlain by uppermost Precambrian through lowest Cambrian strata termed the “Morrison River Formation’ (designation abandoned). This depositional sequence consists of three formations: 1) red beds through tidalites of the Rencontre Formation (to 279+ m; =“Kelvin Lake Formation,’ designation abandoned); 2) prodeltaic clastics of the Chapel Island Formation (to 260 m); and 3) macrotidal quartzites of the Random Formation (to 71 + m). Post-Random block faulting and 300 m of local erosion took place prior to onlap of the “MacCodrum Formation’ (abandoned). Siliciclastic mudstones of the lower “MacCodrum’ are re-assigned to the middle Lower Cambrian Bonavista Group. Sub-trilobitic faunas from the Bonavista Group include “Ladatheca’ cylindrica from the West Centre Cove Formation(?) and higher diversity faunas (23 species) in the Camenella baltica Zone of the Cuslett and Fosters Point Formations. Trilobite-bearing, upper Lower Cambrian (Branchian Series) strata (Brigus Formation, =upper “MacCodrum’ and overlying “Canoe Brook’ Formations) unconformably overlie the Placentian Series in Cape Breton Island, southeastern Newfoundland, Shropshire, and, probably, eastern Massachusetts. Correlations based on small shelly fossils indicate an earlier appearance of trilobites in Avalon than on the South China Platform. Twenty-six species are illustrated. Halkieria fordi n. sp., the conodont(?) “Rushtonites’ asiatica n. sp., and the zhijinitid(?) Samsanoffoclavus matthewi n. gen. and sp. are described. Ischyrinia? sp. may be the oldest ischyrinoid rostroconch.

The species Pleurostomella concava is a new benthic foraminifer recognized in Oligocene and Miocene sediments from the Indian and Pacific Oceans. The first mentioned finding of this species is in the material recovered from the experimental Mohole drilling near Guadalupe Island off Baja California. The morphology of Pleurostomella concava differs distinctively from other species of the genus Pleurostomella by its concave apertural face and keel-like rim around the ultimate chamber.

Conical and vase-shaped calathids are found in the Lower Ordovician Fillmore Formation of western Utah associated with intraformational conglomerates and small patch reefs. Calathium yersini n. sp. exhibits patterns of both the inner and outer walls of calathid two-wall construction. The broadly annulate walls are constructed from meroms with fused proximal merom feet forming the inner wall. The reticulate-patterned outer wall is formed by interlocking stellate ribs at the distal end of each merom. Latitudinal (horizontal) ribs interlock adjacent merom ribs side by side at the tips of ribs while meridional (vertical) ribs overlap merom shaft to merom shaft. Inner and outer walls are perforate. Pore-canal casts preserved in silicified molds suggest an exit and entrance current circulation for inner and outer wall pores. Upper ends of the calathids are not preserved, but an open cup is interpreted from infill material and encrustation of the interior cup wall by epibionts. Epibionts commonly encrust and thicken Calathium outer walls, with the cyanobacterium Girvanella as the dominant encrusting organism. Calathium yersini n. sp., among the earliest of receptaculitids, has a morphology suitable for water circulation consistent with that of filter-feeding organisms.

Laminae of genera considered in this revision are sheets of planar, compact tissue (order Clathrodictyida) or a network formed by arms (colliculi) emerging from pillars (order Actinostromatida). Pillars, confined to a single interlaminar space, are simple rods, branch upwards, or have complex cross sections. The scope of Anostylostroma is limited to species with complexly upwardly branching pillars and simple planar laminae. Species with predominantly y- or v-shaped pillars are removed to Schistodictyon. Simplexodictyon is limited to species with double laminae formerly referred to Diplostroma. A new genus, Petrostroma (type species: Simplexodictyon simplex Nestor), is proposed for species with simple, planar laminae and rodlike pillars. The scope of Atelodictyon is restricted to species with planar, simple laminae resembling the type species and many species with laminae formed of colliculi previously placed in this genus are assigned to Aculatostroma. Other genera discussed include: Crumplestroma and Coenellostroma (both synonyms of Aculatostroma), Pseudoactinodictyon, Stelodictyon, Clathrodictyon, and Nexililamina and Coenostelodictyon (both synonyms of Schistodictyon).

Three more thalamid sponge species are described from Upper Permian reefs of Djebel Tebaga, Tunisia. Intrasporeocoelia hubeiensis Fan and Zhang, 1985, Rhabdactinia depressa Rigby, Fan, and Zhang, 1989, and Glomocystospongia gracilis Rigby, Fan, and Zhang, 1989, are now known from a few Tunisian specimens.

Monaxon spicules are common within the rigid, diagenetically altered, aragonitic skeleton of Glomocystospongia gracilis Rigby, Fan, and Zhang, 1989. Spicules are common as vertical elements in walls of tubes between the vertical series of cyst-like chambers and less common in the chamber walls where they are parallel to the tube walls but project out into the chambers.

Intrasporeocoelia has been reported from Permian rocks of the Sosio Valley in Sicily, and therefore from the Western Tethys. However, the species of Rhabdactinia and Glomocystospongia reported here have been known, until now, only from the Permian of China; thus, the Djebel Tebaga locality in southern Tunisia represents the first known occurrence of these latter sponges in the Western Tethyan realm.

Two additional specimens of Tristratocoelia rhythmica Senowbari-Daryan and Rigby, 1988, have also been found. They allow further definition of characteristics of this sponge, which was initially described from a single specimen from Djebel Tebaga.

Recognition of discrete taxa is an enduring problem in the biological sciences, especially for taxonomists who work with groups that display a great degree of homeomorphy at low taxonomic levels. Selection of the type and number of characters used to make taxonomic distinctions is important because it reflects taxonomic concepts for a group as a whole. Often the validity of characters used to develop classifications is not documented and resulting classifications are therefore suspect. However, classifications can be tested for their objectivity with numerical analysis and characters can be evaluated for their relative value for making taxonomic splits by a variety of statistical techniques. In addition, evaluation of the distribution of character states can lead to insights into evolutionary histories of any group. This study provides such an analysis.

Fenestrate cryptostome Bryozoa are abundant and diverse in many upper Paleozoic rocks, and are therefore potentially highly useful for a variety of paleontologic studies. However, study of fenestrates is hampered by necessary complex preparation techniques and problems encountered with homeomorphy. In addition, inconsistent applications of inadequate methodologies have contributed to an unsatisfactory taxonomy. Results from cluster and discriminant analyses demonstrate that fenestrate species can be objectively recognized. Species distinctions are most clear when all available characters are used, although some characters are more diagnostic than others.

Results from cluster and discriminant analyses suggest that fenestrate genera represent major evolutionary shifts associated with the development of key character(s) that allowed entry into new adaptive zones. Key characters allow for an oligothetic classification of genera, which is not merely an artifact created to simplify taxonomic analysis. Diversification of species within adaptive zones resulted in a natural hierarchy of genus-level and species-level characters. Iterative evolution at the species level within separate adaptive zones resulted in a great deal of homeomorphy.

Morphometric analysis provides insights into several aspects of the paleobiology of this traditionally problematic group. Similar comprehensive studies may prove equally productive for other groups.

Worthenopora is a Mississippian cryptostome bryozoan genus with certain characteristics that so closely resemble those of some cheilostomes (Jurassic–Recent) that previous bryozoan experts speculated whether Worthenopora should be assigned to the order Cheilostomata. This raises the question of possible affinities between cryptostomes (class Stenolaemata) and cheilostomes (class Gymnolaemata). Based on wall structure, growth sequence, zooecial shape, and secondary structures such as stylets, Worthenopora is here shown to be a stenolaemate, assignable to the suborder Ptilodictyina with other bifoliate cryptostomes. Although the exterior appearance of Worthenopora superficially resembles some cheilostomes, it represents rather limited divergence from more typical bifoliate growth patterns. Additionally, presence of characteristics such as elongate zooecia with thin exozones, cuticular medial plane, and distinctive exterior ridges justifies retention of the monogeneric family Worthenoporidae. Three species (W. spatulata, W. spinosa, and W. valmeyerensis), known only from North America and primarily restricted to the Illinois Basin, are recognized. Analysis of apertural spacing in these species suggests a trade-off between feeding efficiency and occupation of water-column space. Worthenopora valmeyerensis is considered a hypermorphic derivative of W. spinosa.

Lyrischapa Aldrich (1911), originally described from the Eocene of North America, is represented in the Old World Tethyan paleobiotic province by three species that previously have been referred to other genera: L. haimei (d'Archiac), from the late Paleocene or early Eocene upper Ranikot Formation of Pakistan; L. sismondai (d'Archiac), from the upper Ranikot Formation and the late Paleocene Hangu Shales of Pakistan; and L. soudanense (Douvillé), from the late Paleocene Kalambaina Formation in the Republic of Niger. A fourth unnamed species of Lyrischapa may be represented by an internal mold from the middle Eocene Khirtar Formation of Pakistan. Lyrischapa probably originated within the ancient Tethys seaway between Eurasia and the Gondwana continents of Africa and southern India because its oldest known occurrence (late Paleocene) and closest relatives (Indovoluta Eames, 1952; Gosavia Stoliczka, 1865, 1868; possibly also Diconomorpha Wenz, 1943) are in that region. It has no apparent ancestor among described American Paleogene or Cretaceous Volutidae. Because its large protoconch suggests that it lacked a teleplanic larval stage, the trans-Atlantic migration of Lyrischapa to the New World probably resulted from chance dispersal, either by rafting of egg masses attached to floating plant debris or by drift of floating egg capsules.

Nine assemblages of conodont elements have been found on bedding surfaces of the “Wolfcamp Shale’ from the Midland Basin, Texas. Four of these assemblages have Pa elements assigned to Sweetognathus cf. S. inornatus. The assemblages are classified taphonomically as apparatus (remains or partial remains of a single individual) or coprolitic associations. The two apparatus assemblages indicate that Sweetognathus cf. S. inornatus possessed a seximembrate apparatus comprised of Pa, Pb, M, Sa, Sb, and Sc elements. Five of the seven coprolitic associations contain numerous elements (50–100) and/or multiple pairs of Pa elements representing the presumably ingested remains of two or more conodonts.

The “Wolfcamp Shale’ assemblages are significant because 1) they confirm the polygnathacean affinity of the family Sweetognathidae, 2) they represent the youngest polygnathacean assemblages currently known, and 3) they permit comparison of multielement Sweetognathus with homologous elements of coeval genera such as Hindeodus, Adetognathus, Streptognathodus, and Neostreptognathodus.

At least four of the seven described species of Amyzon are valid species with doubtful status given to Amyzon pandatum Cope, 1874, and Amyzon fusiforme Cope, 1875. Amyzon gosiutensis Grande, Eastman, and Cavender, 1982, is a junior synonym of Amyzon aggregatum Wilson, 1977b. The Klondike Mountain Formation specimens examined from Republic, Washington, are identified as Amyzon aggregatum Wilson, 1977b. The known range of A. aggregatum is extended south to Republic, Washington, and southeast to the Laney Shale Member of the Green River Formation, Wyoming.

A single specimen of the platyceratacean gastropod Raphispira showing one complete and one incomplete, slightly elliptical borehole was recovered from the Antelope Valley Formation in central Nevada. Circular boreholes may be formed by a variety of causes, but they are most commonly attributed to the predators. In the Paleozoic the holes are most common in brachiopods, both calcareous and phosphatic. This is the oldest reported occurrence in a calcareous shell. In most instances, if a hard-bodied form is consumed by a carnivore, little recognizable evidence remains; therefore, predator boreholes are helpful in determining trophic relationships.

Uppermost temaikan strata from southwest Auckland Province, North Island, New Zealand, have recently yielded a small fauna of Middle Jurassic ammonites previously believed to be endemic to the eastern Pacific borderlands, although a single fragment of the new species described below was previously reported in a large Tethyan assemblage from Papua, New Guinea, by Westermann and Callomon (1988). The New Zealand assemblage consists of the dimorphic pair Xenocephalites (♂) and Lilloettia (♀) with close morphologic ties to species from the latest Bathonian Steinmanni Standard Zone of the Andean Province (Riccardi et al., 1989). This new find permits direct time-correlation of the uppermost part of the Temaikan Stage (Marwick, 1951, 1953) with the East-Pacific latest Bathonian Steinmanni Zone and with the East-Tethyan Late Bathonian Macrocephalites apertus Association. The upper Temaikan Stage of south Otago Province, southeastern South Island, New Zealand, has also yielded rare representatives of the Tethyan Macrocephalitinae, so that the New Zealand area in the late Middle Jurassic was in the overlap area of Tethyan and East-Pacific Subrealms.

Most fossil echinoderms are unknown as complete skeletons because they have easily disarticulated appendages. This is the case of paracrinoids, which have a ruggedly constructed theca but fragile brachioles and attachment structures. In their monographic review ofparacrinoids, Parsley and Mintz (1975) figured only one species (Comarocystites punctatus Billings, 1854) showing essentially complete skeletal morphology. Paracrinoids have no good modern analogues and therefore the task of evaluating their lifestyles is complicated.

Recently, several dinosaur bones were rediscovered in the paleontological collections at the University of Tennessee, Knoxville, with a label indicating that the material was collected from the Cretaceous of west Tennessee. Since dinosaur remains have never been reported from Tennessee, this discovery prompted further investigation.