Tectatodinium rugulatum (Hansen, 1977) McMinn, 1988, from the lower Danian of Denmark, is considered conspecific with, and a junior synonym of, the extant thermophilic species Tectatodinium pellitum Wall, 1967. However, the Danian material, based on holotype and topotype specimens, appears to show a degree of morphologic variability not seen in younger material. The accepted stratigraphic range base of Tectatodinium pellitum is now extended to the lower Danian, where this species appears to be a useful biostratigraphic marker in the Danish North Sea basin.

Massive Upper Triassic (Norian) reef limestone at Eaglenest Mountain, Takla Group, British Columbia, contains a wide variety of shallow-water fossils in two different carbonate units. A sponge-coral facies contains the sponges Fanthalamia astoma (Seilacher, 1962), Fanthalamia multicanalis new species, Cinnabaria expansa (Seilacher, 1962), and Cinnabaria? sp. Cinnabaria expansa is a widely distributed North American terrane species which, along with F. astoma, was previously known from the Luning Formation of Nevada. Also included is the “disjectoporoid,” Pamiropora sonorensis Stanley, 1994, and a massive spongiomorph, Spongiomorpha tenuis Smith, 1927, previously endemic to the Eastern Klamath terrane of California. Colonial corals include: Retiophyllia quesneliana new species, Chondrocoenia waltheri (Frech, 1890), Crassistella cf. juvavica (Frech, 1890), Distichomeandra cf. austriaca (Frech, 1890), and Alpinophyllia flexuosa Roniewicz, 1989. A limestone conglomerate overlying these beds is dominated almost exclusively by the planktonic hydrozoan, Heterastridium conglobatum Reuss, 1865. A problematic taxon Lovcenipora cf. chaetetiformis Vinassa de Regny, 1915, is reported for the first time outside Timor and the Tethys. The faunas provide a first glimpse into the reef biota of the Quesnel terrane. They contain taxa previously known from the distant Tethys but also include endemics from other inboard terranes.

During growth of colonial corals, the basic organization of skeletal elements was determined by inherent factors, but arrangement of corallites within a colony could be affected if environmental change induced a modified growth form. Comparisons of internal and external characters during colony development indicate how environmental and genetic factors determined growth form. The results of these comparisons have implications for understanding of colony integration, functional morphology, and systematics.

This study is based on serially sectioned coralla of the cerioid tabulate Paleofavosites subelongus, from the uppermost Ordovician to lowermost Silurian of the east-central United States. Colony growth form resulted from changes in maximum growth angle of marginal corallites, and in the shape of the growth surface. These features were coordinated with corallite characters and were dependent on variation in corallite growth. At the same time that a colony became broader by expanding its maximum growth angle and developing a taller growth surface, its corallites became larger, more new corallites were initiated, and recently initiated corallites expanded more rapidly. When a colony's maximum growth angle was reduced and the growth surface became flatter, corallites also became smaller, fewer corallites were initiated, and those corallites that were recently initiated expanded slowly.

Genetic constraint of growth is illustrated by consistent patterns of initial colony growth, and by relationships among characters of internal and external morphology. Frequent small-scale variations in growth angle and growth surface height:width during astogeny indicate fluctuating environmental factors. Sedimentation and subsidence of the colony were probably the major environmental controls on form.

An enteletid brachiopod genus Peltichia Jin and Liao, 1981, is reviewed and emended based on specimens from the Permian sequences of Japan, South China, Vietnam, and Transcaucasia. New and revised taxa are Peltichia akasakensis (Ozawa), P. kwangtungensis (Zhan), P. ruzhencevi (Sokolskaja), P. sinensis (Huang), P. subtriangularis new species, P. transversus (Huang), and P. zigzag (Huang). The genus Peltichia, consisting of 10 species, ranges from Kungurian to Changhsingian, and is distributed geographically in the Tethyan Realm and its surrounding areas and probably as well as in the western Panthalassan region.

No trilobite species, and very few genera, pass from the Lower (Ibexian) into the Middle Ordovician (Whiterockian), which is a turning point in Laurentian trilobite history. Trilobites from three sections exposing the base of the Whiterock Series (basal Middle Ordovician) in Nevada are described and illustrated. They are attributable to different, and generally more open-shelf, biofacies from the Bathyurid biofacies trilobites described from the Ibex area, Utah, by Fortey and Droser (1996), but include species in common, which allow correlation into the Ibexian type section. At Little Rawhide Mountain the basal Middle Ordovician is developed in Olenid biofacies, described for the first time in western North America from rocks of this age. Correlation based on species-level similarity shows that the “spike” that has been used to define the type base of the Whiterockian (and hence the Middle Ordovician) at Whiterock Canyon is at a level younger than the base of the Whiterockian assumed in recent discussions of its international correlation. The type Whiterock base correlates with the Psephosthenaspis glabrior trilobite Subzone at Ibex, well above the major change in trilobite faunas at the base of the Psephosthenaspis Zone (P. microspinosa Subzone). In all study sections there is an abrupt change of facies after trilobite Zone J, possibly associated with regression. Four new species are described: Cloacaspis tesselata, Harpillaenus rossi, Acidiphorus? lineotuberculatus, and Benthamaspis serus.

Extremely well-preserved specimens of the species Rennensismilia complanata and Aulosmilia cuneiformis occur in Santonian (Upper Cretaceous) strata of the Lower Gosau beds, near Gosau, Austria. Two of these, here reported, have aragonitic skeletal mineralogy and skeletal structures that are typical for their families, and, in addition, show distribution of trace elements (Sr and Mg above all) that confirm the biogenic origin of structures observed. R. complanata also has proteinaceous matrix preserved within its skeleton, which, seen here for the first time in electron micrographs of living or fossil corals, forms sheaths of organic matrix surrounding bundles of skeletal crystallites. Matrix is most abundant along the axial plane of septa, which also is the first-formed part of each septum. Although A. cuneiformis lacks observable organic matrix materials, its skeletal structure and its distribution and amount of trace elements are analogous to that seen in R. complanata and also in modern corals.

Two new fossil worms are described from the Lower Cambrian Kinzers Formation of southeast Pennsylvania. Both are unique specimens. Kinzeria crinita new genus and species has a body divided into three regions. The head bears a prominent set of elongate tentacles, presumably employed for feeding. The elongate trunk tapers slightly in a posterior direction. It contains a prominent intestinal tract, the contents of which indicate a deposit feeding habit. The tail is an expanded structure, with either a spatulate or sagittate outline. The mode of life of K. crinita is uncertain, but the animal may have been semi-sedentary. Atalotaenia adela new genus and species is more poorly known, lacking the anterior. The preserved body is vermiform, with external annulations and a rounded posterior. There is a prominent internal strand, consisting of a probable intestine and an associated fibrous unit, possibly representing muscles. This worm may have been infaunal. These discoveries extend further our understanding of the ancient diversity of Laurentian Burgess Shale-type faunas. In common with the Burgess Shale itself and the Sirius Passet fauna (Peary Land, Greenland) the location of fossil-Lagerstätte [see Shields (1998) for a discussion of the terminology of Lagerstätten] of the Kinzers Formation adjacent to a prominent escarpment reinforces earlier evidence of the paleotopography exerting an important control on the distribution of Burgess Shale-type faunas. Whether this is a result of localized faunal abundances or taphonomic control is, however, uncertain.

The distributions of trilobite species were controlled by a combination of habitat preferences and paleogeographic constraints, which tend to limit their extent. The Lower Ordovician trilobite Carolinites genacinaca Ross, 1951, however, had a remarkable range unequaled among polymerid trilobites; it has been recognized on all Ordovician paleocontinents. Its distribution has been explained by an epipelagic mode of life, based on evidence from functional morphology, analogy with modern pelagic crustaceans, and geological occurrence. In such a case, morphological identity throughout its range might be anticipated, if all occurrences can be postulated to be members of a single pandemic population. Rotational superimposition has been used to compare variation within samples drawn from Alberta, Spitsbergen, and Australia with a benchmark population from the western United States. All are morphometrically similar. By any criterion, specimens identical to the benchmark population are found within the Alberta, Spitsbergen and Australia samples, which represent the extremes of the species' geographic range. A lone cranidium from France, previously referred to Carolinites vizcainoi, may be a juvenile of C. genacinaca or C. tasmaniensis; its differences are consistent with ontogeny. A small number of specimens from Siberia and central China show differences in cranidial proportions from the Utah specimens that may be the result of preservational factors and/or photographic technique, or may represent genuine morphological disparity; this could be clarified if more specimens were to become available. This study suggests that C. genacinaca was ubiquitous in the epipelagic environment in a belt that encircled the planet between paleolatitudes of approximately 30°N and 30°S.

Palaeacmaea typica, the type species of the genus, and P. irvingi, the only other Late Cambrian taxon considered congeneric are redescribed herein. Their morphology suggests that they are neither Monoplacophora, where they are currently assigned, nor are they Mollusca. Specimens of P. irvingi demonstrate considerable variation in shape, interpreted as distortion of a flexible integument, of essentially no thickness. A neotype is designated for P. irvingi; it is interpreted as a medusiform fossil, possibly a cnidarian. Only the holotype of P. typica is known, but it shows comparable features. The genus and the family Palaeacmaeide are placed in Phylum Incertae Sedis. Four Ordovician species previously assigned to Palaeacmaea, show none of the characteristics noted, and they are tentatively reassigned to other genera.

Delicate symmetrical structures in living chambers of autozooecia of some lower Paleozoic species of the order Trepostomata have been interpreted as indications of polypides with little further elaboration. Applications of the anatomy, mode of skeletal growth, and functional requirements basic to living species permit recognition of a few organs of these partially preserved polypides, their functions, and their relationships to enclosing skeletons. Only one basic polypide anatomy is indicated in lower Paleozoic trepostome species, in contrast to the wide diversity of polypide anatomy and their lack of correlation with skeletal characteristics in living stenolaemates. In general, the longer the evolutionary history, the greater the diversity of skeletal morphology in stenolaemates. Apparently, polypide diversity and lack of correlation with skeletal morphology also have increased over time.

The complex skeletal septa in autozooecial apertures of the lower Paleozoic trepostome Hallopora have been interpreted as reflecting an organ of full-sized feeding polypides. Applications of the basic biological concepts of living species suggest that the septa provided reduced skeletal apertures to fit smaller polypides of polymorphs that secondarily occupied the living chambers of full-sized degenerated feeding polypides.

Dicoelosia occurs in two deep water benthic shelly assemblages on an Early Silurian (uppermost Aeronian, Stimulograptus sedgwickii Zone) carbonate ramp to shelf, within the 25 m thick bluish-grey mudstone of the Richardson Member in the middle Jupiter Formation, Anticosti Island, Québec. Dicoelosia dauphinensis new species is erected on the basis of its relatively large, elongate shell, with a concavo-convex lateral profile, moderately wide, planoconvex lobes and subparallel lateral margins. Dicoelosia dauphinensis first occurs in a Gotatrypa-Dicoelosia Community, in which it constitutes about 7 percent of the individuals within sampled populations. This is replaced about 2 m up section by a Resserella-Dicoelosia Community, where D. dauphinensis makes up 22 percent of the individuals preserved on single bedding planes. Subsequently, Dicoelosia becomes a rare component of the Stegerhynchus-Triplesia Community in a shallowing-upward succession of the upper Richardson Member. It is in this upper Richardson shelly community that Stimulograptus sedgwickii is locally common, together with in situ brachiopod nests of Eocoelia, Triplesia, and Lissatrypa at the upper Jupiter Cliff section. The water depth estimated for the Resserella-Dicoelosia Community is between 100-120 m, below the normal depth range of the Clorinda Community (BA5) on Anticosti, in a distal shelf setting about 80-100 km offshore from the Laurentia paleocontinent, on the west side of the Iapetus Ocean. The interpretation of water depth is based on the facts that, 1) Dicoelosia-rich communities are confined to strata, which lack shallow water sedimentological evidence such as thick calcarenites and hummocky cross stratification, 2) Dicoelosia does not occur with shallower water taxa seen in the overlying Clorinda and Stricklandia communities associated with cyclocrinitid algae, corals and stromatoporoids in the Cybèle Member, and 3) Dicoelosia occurs only in the deeper water sections of the Richardson Member, some 10-15 km basinwards from mid-shelf shallower Richardson facies of the Anticosti Basin. Thus, the Dicoelosia-rich communities are interpreted to mark a maximum flooding surface within the distal shelf to ramp Llandovery succession of Anticosti Island.

Upon restudy, Quasidentalium Shimansky, 1974, is transferred to the Coleolidae, a group of “Vermes” that form a calcareous tube.

The scolecodont genera Nereidavus Grinnell, 1877, and Protarabellites Stauffer, 1933, have been used for several different fossil polychaete taxa over the years. Nereidavus is here considered a nomen dubium, as the holotype of the type species is lost and the original information is insufficient for identification. Protarabellites is reevaluated and constitutes, besides Ramphoprion, a second genus in the family Ramphoprionidae. The “paratype” of N. varians (named Ramphoprion sp. in this paper), and the holotype of P. humilis are redescribed.

A new and unusually well preserved bivalve fauna of Late Ordovician age was recovered from pebbles within the Late Ashgill (Hirnantian) glacigenic diamictite of the Don Braulio Formation, in the Argentine Precordillera. According to the associated brachiopods and the presence of graptolites of the bicornis Zone in the matrix of the diamictite, an early Caradoc age is accepted for the bivalve fauna. The clasts contain bivalve molluscs representing nine genera, of which seven are new. Identified taxa are the following: Praenucula sp., Cuyopsis symmetricus new genus and species, Villicumia canteraensis new genus and species, Trigonoconcha acuta new genus and species, Concavodonta ovalis new species, Hemiconcavodonta minuta new genus and species, Hemiconcavodonta sp., Emiliania cuerdae new genus and species, and Concavoleda braulense new genus and species. Two new subfamilies are proposed: Praenuculinae and Concavodontinae. The genera Praenucula Pfab, Cuyopsis new genus, Villicumia new genus, and Trigonoconcha new genus are included in the new subfamily Praenuculinae. The genera Concavodonta Babin and Melou, Hemiconcavodonta new genus, and Emiliania new genus are included in the new subfamily Concavodontinae.

The ontogenies of three new species of Telephinidae, Telephina calandria, Telephina chingolo, and Telephina problematica are described from Arenig-Caradoc strata in the Argentine Precordillera, and compared with the larval stages of some other Proetida, including other telephinids.

New findings reveal 1) a radical metamorphosis in the ontogenies of these Telephina species late in the meraspid period, not previously described among Trilobita; and 2) distinctive hypostomes of Telephinidae containing long, thin anterolaterally and dorsally splayed anterior wings. Early ontogenies of different species currently assigned to the genus Telephina fall into at least two distinct morphological and life history groups, and hypostomes (if correctly assigned in previous works) vary significantly. The three new species strengthen the hypothesis of a phylogenetic connection between Oopsites and Telephina.

Three morphological types of protaspid instars are described for proetide trilobites. Two are anaprotaspides, and the third is a metaprotaspis. They always occur in the same sequence in the ontogeny, but no cases are known of all three types in the same species. These larval types are important for understanding the systematics and life cycles of the Proetida. Benthic/pelagic transitions identify four life history patterns among the the Proetida. The best larval synapomorphy for the Proetida is the distinctive metaprotaspid larval type, which is absent in very few proetides (some Telephinidae), perhaps as a result of heterochronic displacement of this stage into the meraspid period.

The first formal report of Tertiary portunid crabs for Mexico is based on two new species, Portunus atecuicitli and Necronectes tajinensis, from the middle Miocene beds of the Tuxpan Formation in Veracruz, east-central Mexico. Associated crustacean remains include fragments of calappid fingers, calappid carapace fragments possibly assignable to Matuta Fabricius, and callianassid hands. Low tolerance to osmotic variations of recent species of Portunus confirms paleoenvironmental interpretations for shallow, euryhaline, tropical waters during deposition of the Tuxpan Formation.

The component subfamilies of the Delthyridoidea are critically reviewed and subjected to phylogenetic analysis. This shows the presence of two clades, assigned to the Delthyrididae and Acrospiriferidae, within the superfamily. The subfamilial categories are redefined mainly on the basis of the characters used in the phylogenetic analysis. The spiriferid, mainly delthyridide, Gaspé fauna is formally revised and redescribed. This new taxonomic treatment leads to more precise biostratigraphy and to the recognition of a new subfamily, the Gaspespiriferinae, based on the new genus Gaspespirifer. Five new species are described: Howellella (Howellella) forillonensis, Brachyspirifer (Brachyspirifer) briseboisi, Paraspirifer desbiensi, Brevispirifer florentinus, and B. quebecensis, The occurrence of Brevispirifer species with Middle Devonian chonetaceans confirms the presence of marine Eifelian strata in the Matapédia Valley. Paraspirifer desbiensi n. sp. and two species left in open nomenclature, Vandercammenina sp. and Mucrospirifer sp., have considerable biostratigraphic and biogeographic significance in the Lower Devonian. The first occurrence in the Eastern Americas Realm of the typically Rhenish genera Brachyspirifer, Paraspirifer, and Vandercammenina are in Gaspé. This reinforces the hypothesis that Gaspé served as a stepping stone for Rhenish species invading North America in Pragian and Emsian times, as previously suggested by bivalve biogeography.

Very few Jurassic bryozoan faunas are known outside Europe. Here we describe seven species of calcareous cyclostome bryozoans and one bioimmured soft-bodied ctenostome bryozoan (Simplicidium sp.) from the Middle Jurassic (?Bathonian) Carmel Formation of Utah. Three of the cyclostomes are placed in open nomenclature due to inadequate preservation and/or the lack of key reproductive polymorphs. A new genus, Patulopora, is established for Diastopora cutleri Cuffey and Ehleiter, 1984, following the discovery of gonozooids that place this species in the Multisparsidae rather than in the Plagioeciidae. Another of Cuffey and Ehleiter's (1984) species—Berenicea duofluvina—is reassigned to Microeciella on the basis of the gonozooids, and a similar but distinctly smaller form is described as M. pollostos new species. A second new species—Hyporosopora nielsoni—is a rare colonist of hardground undersurfaces. The Carmel bryozoan fauna is compared with better-known faunas from the northern European Middle Jurassic. Species richness and colony-form diversity fall well within the expected values for bryozoan faunas of this age, and endemism is detectable only at relatively low taxonomic levels. Evolutionary patterns based on studies of contemperaneous European bryozoan faunas during this time of cyclostome evolutionary radiation are reinforced by the palaeogeographically distant Carmel bryozoan fauna.

New specimens representing species of Cyrtiopsis Grabau, 1923, described by Grabau (1931a) were recovered in samples from the Late Devonian deposits of the Changlongjie Member of the Xikuangshan Formation in central Hunan Province of South China. Associated Famennian age conodonts and morphotypes of the rhynchonellid brachiopod Yunnanellina lineage fix the ranges of species of Cyrtiopsis and related taxa in the Xikuangshan Formation within the interval of the Middle triangularis Zone through the Lower crepida Zone (early Famennian) in central Hunan Province.

Detailed study and comparison of external and internal shell structures of the type species of Cyrtiopsis Grabau, 1923, and related species described in Grabau (1931a) shows that Cyrtiopsis from South China includes the type species, C. davidsoni (embodied by the holotype), and C graciosa. Both of these species are shown to lack a delthyrial plate. Grabau's paratypes of C. davidsoni are considered to belong in Cyrtiopsis intermedia Grabau, 1931. The species C. kayseri Grabau, 1931, and C. shensiensis Grabau, 1931, are also deemed synonyms of C. davidsoni Grabau, 1923 (as restricted above). “Cyrtiopsis” intermedia differs from other species of Cyrtiopsis by development of a short delthyrial plate and its systematic position remains uncertain.

The genus Pseudocyrtiopsis is proposed with Cyrtiopsis spiriferoides Grabau, 1931, as the type. Pseudocyrtiopsis new genus is distinguished from Cyrtiopsis Grabau, 1923, by its alate hinge and development of a delthyrial plate. Comparisons of species of Cyrtiopsis from South China with cyrtospiriferid brachiopods identified as Cyrtiopsis by Crickmay (1952) demonstrate that none of the early Famennian species from western Canada can be assigned to the genus as revised here, although C. mimetes Crickmay, 1952, is closely related to “C.” intermedia Grabau, 1931.

The only two known life associations of the shell and operculum of Maclurites Le Sueur, 1818, are described for the first time. Maclurites cf. magnus Le Sueur, 1818, from the Middle Ordovician of Alaska demonstrates that the operculum fits slightly inside the aperture, and when closed, the operculum extends down below the base of the shell and may have acted as an anchor. The operculum of Maclurites bigsbyi (Hall, 1861), from the Middle Ordovician of Wisconsin, is illustrated for the first time and is confirmed to be distinct from Maclurina logani (Salter, 1859).