Four species of isorophinid edrioasteroids, Ulrichidiscus forbesi n. sp., Neoisorophusella whitesidei n. sp., Postibulla westergaardi n. sp., and Parapostibulla graysoni n. sp., are described from unnamed unit 1 of the Golf Course Formation, Dornick Hills Group, Lower Pennsylvanian (Morrowan), at Forbes Ranch, north of Marietta, southern Oklahoma. This locality is the first report of edrioasteroids attached to extraformational clasts, and they exhibit extremely high specimen density and the highest taxonomic diversity known from the post-Ordovician. The associated fauna consists of the stemless crinoid Paragassizocrinus tarri, serpulid worm tubes, and the acrothoracic barnacle boring, Rogerella, along with a few brachiopods, rugose corals, and other open marine organisms. Edrioasteroids show no preference for clast type, size, or shape. Intraspecific spatial competition is shown by polygonal specimen outlines in highly crowded conditions, whereas interspecific competition results in specimen overgrowth in a predictable manner.

One new species of retiolitid, Gothograptus storchi, five new species of monograptids (Monograptus patulus, Monograptus glutiformis, Streptograptus galeus, Testograptus cubitus, and Monoclimacis capillus), and one new cyrtograptid, Cyrtograptus palmatus, are described from the lower Homerian lundgreni Biozone of Arctic Canada. The presence of a species of Gothograptus in the Cyrtograptus lundgreni Biozone of Arctic Canada is documented for the first time. Further, full-relief specimens of Cyrtograptus multiramis Törnquist? and C.? urbaneki Teller are described. Better and more completely preserved, isolated material of Sokolovograptus cf. S. parens Obut and Zaslavskaya, Pseudoplectograptus sagenus, Cometograptus apsis, C. nevadensis, Monograptus biglossa, Cyrtograptus hamatus, C. lundgreni, and C. radians, previously described in Lenz and Kozłowska-Dawidziuk (2001a), is also illustrated. The total global species diversity of the lundgreni Biozone thus approaches 50, making the subsequent extinction event even more profound.

The growth of the food-gathering systems of Ordovician crinoids illustrates the solutions evolved to avoid or minimize problems of suspension feeding and maintenance. The column has low metabolic requirements and may even be self-sufficient; little or no food need be diverted from the crown to the column. The tissue that the food-gathering system supplies with food is all or mostly in the crown. The volume of tissue in the crown is isometric with its volume. Distal arm branches, ramules, or pinnules form throughout growth of most taxa. The number of arm branches is constant in hybocrinids and porocrinids. The length and number of plates in the food-gathering system show marked positive allometry relative to crown volume. Food grooves become wider in larger crinoids but growth rates vary greatly. Branch density declines in all species studied. The tubefoot spacing can be constant, increase, or decrease in larger crinoids. Food-gathering capacity is the number of food-catching tubefeet multiplied by the average food-groove width, and it is positively allometric in terms of crown volume. The food-gathering ratio (food-gathering capacity: crown volume) declines somewhat, remains the same, or increases slightly during growth. The food-gathering parameters are correlated with arm structure. Crinoids with pinnulate arms exhibit the highest food-gathering ratios, high values of tubefoot spacing and branch density, and narrow food grooves, and they catch small food particles with small and closely spaced tubefeet. The lowest food-gathering ratios are seen in crinoids with unbranched and nonpinnulate arms which possess low tubefoot spacings and branch densities and wide food grooves. On average these organisms ate larger food items collected by larger and more widely spaced tubefeet. Larger food-gathering ratios are associated with greater resistance to fluid flow through the arms and tubefeet. The allometry of the food-gathering systems of Ordovician crinoids suggests that their metabolic rates could be proportional to body mass0.75 as in many living animals and plants.

Hexactinosidan sponges are important reef-building organisms in Earth history as they are able to create a three-dimensional reef framework and thereby form topographic relief comparable to that produced by scleractinian corals. Study of modern hexactinosidan sponge skeletons from water depths of 165–240 m on the continental shelf off British Columbia, Canada, demonstrate the hitherto undescribed frame-building process that leads to the formation of large and so far unique siliceous sponge reefs in this area. The fundamentals of the frame-building process are based on the production of siliceous envelopes around spicules of dead hexactinosidan sponges. In addition to the development of a three-dimensional reef framework, mound growth is supported by the current baffling effect of the sponges. Fine-grained siliciclastic suspended sediment is trapped and deposited within the gaps in the sponge skeletons and in voids in the reef surface preventing the framework from collapsing as the reef grows.

Analogous but tropical examples from the Lower Jurassic of Portugal show that the frame-building potential of hexactinosidan and other siliceous sponges has existed, substantially unchanged, for more than 180 million years. In contrast to well-known fossil mud mounds of various geologic ages, in which the in situ precipitation of automicrite via microbial processes plays a major role, the matrix of the hexactinosidan sponge mounds of British Columbia consists exclusively of baffled fine-grained siliciclastics; automicrite is absent. Existing mud mound classification schemes do not encompass these depositional characteristics, therefore this new type of mound is consequently here classified as a silicate mound.

Two four-shelled species characterized by a pylome-bearing outermost shell—Sphaeropyle robusta and its descendant, Sphaeropyle langii—are selected for morphological study. Both species are morphologically identical to three-shelled Actinomma morphotypes, morphotypes A and B, respectively. Furthermore, the number of pores on half a circumference of the primary cortical shell, the distinguishing feature between Sphaeropyle robusta and Sphaeropyle langii, accounts for the same between Sphaeropyle robusta and morphotype A, and between Sphaeropyle langii and morphotype B. It suggests that the three-shelled morphotypes A and B are juvenile forms of the four-shelled Sphaeropyle robusta and Sphaeropyle langii, respectively. This is strongly supported by the same stratigraphic distributions of each pair. The quantitative analysis of morphological variations in both species also revealed that they have nearly identical morphology, except for the number of pores on half a circumference of the primary cortical shell. In addition, the size range of primary and secondary cortical shells and the range of the number of radial spines increase in Sphaeropyle langii, while the length range of radial spines decrease.

Long-stemmed eocrinoids are limited to two species in the basal Middle Cambrian Kaili Biota, which occupies the middle portion of the Kaili Formation, Taijiang County, Guizhou Province, China. the Kaili Biota contains preserved soft-bodied organisms shared with either the Chengjiang Fauna (Southwest China) or the Burgess Shale Fauna (British Columbia) or with both. Echinoderms are preserved as limonitic external molds that produce excellent latex casts. Sinoeocrinus lui Zhao et al., 1994 has a complex ontogenetic development, which is described in terms of morphology of holdfast, number of thecal plate circlets, addition and morphology of thecal pores, ambulacral arrangement, and number of brachioles relative to thecal height. Because of the complex ontogeny the following species are now seen to be synonymous with S. lui: lui. S. curtobrachiolus Zhao et al., 1994; S. lepidus Zhao et al., 1994; S. longus Zhao et al., 1994; S. minus Zhao et al., 1994; Paragogia globosa Zhao et al., 1994; and Curtoeocrinus guizhouensis Zhao et al., 1994. A second and rare eocrinoid of undetermined familial and ordinal placement, Balangicystis rotundus n. gen. and sp., has an unusually long holdfast and poreless thecal plates with prominent radial ridges. Sinoeocrinus lui and Balangicystis rotundus inhabited the outer shelf in disaerobic fine-grained shales and mudstones. Megascopic infauna in their community is not present.

Six new species of fenestrate bryozoans, middle to late Wordian, occur in the Gerster Limestone of northeastern Nevada. These bryozoans are similar to lower Kazanian species described from the Russian Platform. The two species of Wjatkella and Polypora from the Gerster Limestone are much more similar to the Russian species than they are to the two species recently described from the allochthonous late Wordian Mission Argillite of northeastern Washington.

New species described from the Gerster Limestone are Rectifenestella cordiretiformis, Wjatkella hemiseptifera, Kingopora wardlawi, Kingopora inflata, Polypora keyserlingiformis, and Polyporella helgersoni. The presence of only six species of fenestrate bryozoans in nearly 260 m of limestone and siltstone is notable.

Discovery of avicularium-like polymorphs in Wilbertopora mutabilis Cheetham, 1954 has provided not only a new opportunity for revising the genus Wilbertopora Cheetham, 1954, but also a more detailed basis for documenting the series of morphological changes by which avicularia differentiated from ordinary feeding zooids in what appears to be the first occurrence of these characteristic cheilostome bryozoan structures in the fossil record.

Eighteen of a total 60 quantitative characters measured on avicularia and ordinary and ovicell-bearing autozooids were sufficient to distinguish eight species of Wilbertopora by discriminant function analysis of zooid data from 93 colonies from the mid-Cretaceous (Albian-Cenomanian) Washita Group in northeastern Texas and southeastern Oklahoma. Eighteen of a total of 20 of the quantitative characters that could be statistically coded for cladistic analysis proved to be informative with respect to parsimony, providing two maximally parsimonious trees for the eight species. Two-thirds of the diagnostic characters involve avicularia. An additional 55 colonies too poorly preserved for morphometric analysis could then be assigned to species qualitatively, with 170 more colonies lacking species-diagnostic characters.

The cladistic trees strongly suggest that most or all of the species diverged before the end of the Albian, but stratigraphic resolution is insufficient to test this hypothesis. Nevertheless, the series of morphological changes differentiating avicularia from ordinary autozooids in these species, based on the cladistic relationships, is highly significant statistically, and may be a pattern later repeated in other cheilostomes.

Wilbertopora and W. mutabilis are emended, and seven new species are described: W. listokinae, W. tappanae, W. spatulifera, W. attenuata, W. improcera, W. acuminata, and W. hoadleyae.

Two new xyloiuloid millipedes (Diplopoda: Chilognatha: Juliformia) are described and placed in the new family Gaspestriidae: Gaspestria genselorum n. gen and sp. from the Emsian of Québec and New Brunswick and Sigmastria dilata n. gen. and sp. from the Pragian of the Midland Valley of Scotland. These new millipedes extend the stratigraphic range of xyloiuloid millipedes, which previously were only described from the Pennsylvanian of Europe and North America. All xyloiuloid millipede families are placed within the superfamily Xyloiuloidea which is left incertae sedis within Juliformia due to a lack of preservation of diagnostic characters that would allow placement within an extant order. The presence in the Lower Devonian of the superorder Juliformia, universally agreed among diplopod taxonomists to represent the most derived clade of Diplopoda, indicates that most of millipede cladogenesis leading to high-rank extant clades had to have occurred by this time, much earlier than previously indicated by the fossil record. A stratocladogram for Myriapoda is constructed, and in combination with data from the plant fossil record and nuclear protein-encoding genes, new hypotheses regarding timing of millipede high-rank cladogenesis in the Paleozoic are formulated. These include terrestrialization of Diplopoda no later than the Ordovician along with the origin of the lineage leading to Penicillata and Arthropleuridea, followed by a period of relative stasis until the Middle Silurian, at which point there was a rapid radiation of Diplopoda, producing most of the high-rank clades by the Lower Devonian.

We used up to 28 morphological characters to discriminate and describe species of the genus Cupuladria based on entire colony specimens collected from both coasts of the Isthmus of Panama. The characters included a combination of zooidal features traditionally used in cheilostome taxonomy and nontraditional characters such as colony size, shape, and an index of calcification of the colony, as well as the size of the basal sectors and their number of pores. Species were discriminated by a series of repeated multivariate cluster and discriminant analyses until the majority of specimens were assigned to their putative species with high statistical confidence. Nontraditional characters contributed significantly to the power of the analyses. Colonies fell into two highly distinct groups most clearly recognized by the presence or absence of vicarious avicularia, which agrees well with previous molecular genetic analyses. Further analyses of each of these two groups considered separately resulted in the discrimination of eight species. These include two previously described Caribbean species, C. biporosa Canu and Bassler, 1919 and C. surinamensis Cadée, 1975, and six new species: C. multesima, C. incognita, C. cheethami, and C. panamensis from the Caribbean, and C. pacificiensis and C. exfragminis from the eastern Pacific. There was also good correspondence between major clades within these morphologically defined groups and the previous molecular analysis, although 20% of the specimens could not be distinguished from their cognate (“geminate”) species from the opposite ocean. The high ratio of undescribed to described species and higher diversity in the Caribbean than eastern Pacific agree well with newly described patterns from other cheilostome genera based on similar analyses. Quantitative morphometric studies are essential to study biologically meaningful patterns of cheilostome speciation and macroevolution in the fossil record.

Two new species of conchostracans, Cyclestherioides wyomingensis and Prolynceus laneyensis, belonging to the Cyclestheriidae and Lynceidae, respectively, are described from the Eocene Laney Member of the Green River Formation of Wyoming, USA. These are the first Cenozoic fossil conchostracans to be formally reported from North America. Cyclestherioides wyomingensis has a close affinity to the extant Cyclestheria hislopi. The latter is a pan-tropical species, found between approximately 30°N and 35°S. Thus, Cyclestherioides may indicate that the Laney Member was deposited in a subtropical setting. The conchostracans and associated fauna of the Laney Member suggest that this member was deposited nearshore in a shallow lake. The concept of Cyclestherioides is emended and some fossil species referred to this genus are revised.

Abundant isolated elements of cornute and mitrate stylophorans were recovered from the upper Tremadocian Tumugol Formation in the Taebaeksan Basin, Korea. Cornute skeletal elements comprise a diverse assemblage of marginals and brachials of cothurnocystid affinities, suggesting the presence of no fewer than four different species. Mitrate remains include numerous isolated adorals, marginals, and aulacophoral plates with typical peltocystidan morphologies. Two adorals are identified as Anatifopsis sp., while all the others are attributable to A. cocaban. However, the two previously documented peltocystidans of Korea, A. cocaban and A. truncata, are sufficiently distinct from other Anatifopsis species to warrant assignment to a new genus, Taebaekocystis. Cladistic analyses suggest that Lagynocystida is the sister group of the clade uniting peltocystidans and mitrocystitidans and that the adorals of Taebaekocystis n. gen. and associated isolated peltocystidan elements possibly account for several different types of peltocystidans, intermediate in morphology between Peltocystidae and Kirkocystidae.

Hystricurus millardensis Hintze, 1953 has been recorded widely in Laurentia. Revision on the basis of abundant new silicified topotype material indicates that most of these records are of morphologically distinct, though related, taxa and that a plexus of related species is involved. The new genus Millardicurus, with H. millardensis as type, is proposed for this clade, which also includes two well-documented new species, M. housensis and M. paramillardensis, from the House Formation of western Utah, several named species from Greenland, and several unnamed new species from various parts of Laurentia that have in the past been referred to M. millardensis. Millardicurus is not apparently closely related to younger Skullrockian-Stairsian hystricurids from Laurentia, but may be related to poorly known coeval Siberian Platform species classified in the genus Nyaya Rozova, 1963. Landmark-based geometric morphometric methods comprising principal component analysis of partial warp scores and Goodall's F test of pairwise means indicate significant shape differences among cranidia, librigenae, and pygidia of the House Formation species of Millardicurus.

Reexamination of type and topotype material revealed the presence of well-developed ventral and dorsal interareas in two virgianid brachiopods from South China, Eoconchidium jiangshanensis Liang (in Liu et al., 1983) and Paraconchidium shiqianensis Rong, Xu, and Yang, 1974, of Late Ordovician and Early Silurian ages, respectively. A cladistic analysis of the common virgianid taxa, incorporating new data on the development of interareas, confirms Paraconchidium Rong, Xu, and Yang, 1974 as a valid genus (not a junior synonym of Pseudoconchidium Nikiforova and Sapelnikov, 1971) and warrants E. jiangshanensis as the type species of Deloprosopus new genus (not allied to either Eoconchidium or Tcherskidium as previously believed). Our preliminary survey on the suborder Pentameridina, based on available material or illustrations of well-preserved, disarticulated (typically silicified) valves, indicates that 1) the interareas are more commonly developed in the superfamily Pentameroidea than was reported previously, especially in the families Virgianidae and Subrianidae; 2) the ventral and dorsal interareas commonly do not occur as paired planar surfaces in the Pentameroidea, as they do in the superfamily Stricklandioidea; and 3) despite the common absence of a ventral interarea, the development of a sharply delimited dorsal interarea appears to be ubiquitous in the Pentameroidea and possibly in the suborder Pentameridina. In the currently adopted classification, the presence of matching ventral and dorsal interareas is treated as one of the diagnostic characters that separate Stricklandioidea from other superfamilies of the Pentameridina. The new data presented herein on the development of interareas imply the need to reevaluate the taxonomic and evolutionary significance of the ventral and dorsal interareas, pending a thorough survey on their distribution in the suborder Pentameridina.

A diverse and well-preserved fauna of shelly fossils from the upper Lower Cambrian Bastion and Ella Island Formations of North-East Greenland contains more than 90 species. the fauna is the most diverse shelly fauna yet discovered in the Lower Cambrian of Laurentia and includes many fossils previously known only from other continental blocks. It enhances correlation of the North-East Greenland succession into Laurentia, most notably with the Browns Pond Formation of New York State, but also with other important Early Cambrian continents, in particular with Australia, Antarctica, and Siberia. A middle Dyeran age is most probable for both the Bastion and Ella Island Formation, and the rich fossil assemblage facilitates correlation with the Botoman Stage of Siberia and its equivalents. One new taxon is described, the disc-shaped problematicum Tunudiscus duovittarius n. gen. and sp.

Thirty-one gastropod species and one type of isolated larval shell are described from a quarry near Ambatolafia in the Mahajanga Basin, northwestern Madagascar. The ammonite fauna indicates a lower Albian age of the fauna (Cleoniceras besairiei Zone). The taxonomic position of the species described earlier is reviewed, incorporating new data on shell structure and protoconch morphology. Twelve species and one genus are new, with four species described in open nomenclature. The oldest hitherto known representatives of Cocculina sensu lato, Iphitus, Conjectura, Entomope, Tomura, and possibly Vatopsis and Paladmete, are described. Nacre is documented in a species of Semisolarium, providing further evidence for the position of this genus within the Vetigastropoda. Eight of the species occur also in the Cretaceous of Europe or are tentatively assigned to European species. Three species have close relatives in the Aptian/Albian of Japan, one species may have relations to the Albian of Texas. The new genus is Mahajangina (family uncertain) for a species having a small, trochispiral teleoconch with spines on the periphery, and a conical, bicarinate larval shell. The new species are: Cirsocerithium collignoni, Zardinistylus betsibokaensis, Pommerozygia mahajangensis, Conjectura minuta, Buvignieria berwaldi, Mahajangina weitschati, Entomope crassilabrum, Paladmete? rasoarinoroae, Tomura ambatolafiensis, Carinathilda parviruga, Carinathilda bandeli, and Gymnothilda pagodoidea.

Multivariate analytical methods, which have been used effectively in work on scleractinian corals, were applied to tabulate corals. The study involved discrimination and characterization of closely related species of Catenipora from the Selkirk Member, Red River Formation, in Manitoba. Ten morphological characters measured in transverse sections of 37 coralla were tested to perform cluster analyses. Results of correlation analysis and principal component analysis indicated that five of the characters would be suitable: tabularium area, corallite length, corallite width, tabularium length, and tabularium width.

A cluster analysis was performed on the raw data matrix coordinated with 37 coralla by the five selected morphological characters. The characters were standardized to mean 0 and variance 1, and squared Euclidean distances among the coralla were calculated. The unweighted pair-group method using arithmetic average was also employed for clustering the coralla. Four morphospecies were consequently extracted from the dendrogram, which was based on the variation of the five morphological characters, and were confirmed by two types of discriminant analysis. Morphospecies A, B, and D have distinctive ranges in variation of all characters except corallite length. Morphospecies C appears to be an intermediate form, in which the ranges of variation of all five morphological characters partially overlap with those of morphospecies A and/or B.

Another cluster analysis, including eight type specimens of Ordovician species previously reported from Manitoba, was performed on the data matrix coordinated with 45 coralla by the five morphological characters. Based on this analysis and morphological comparisons, morphospecies A–C are identified as C. rubra Sinclair and Bolton in Sinclair, 1955, C. foerstei Nelson, 1963, and C. robusta (Wilson, 1926) of Nelson, 1963 (=C. cf. robusta herein), respectively. Morphospecies D is equated with both C. agglomeratiformis (Whitfield, 1900) of Nelson, 1963 and C. aequabilis (Teichert, 1937) of Nelson, 1963 (=C. cf. agglomeratiformis herein). The result of cluster analysis based on the five selected morphological characters demonstrates efficiency in distinguishing closely related species of Catenipora from southern Manitoba. The same procedure should also be applicable to other cateniform corals.

Study of the oldest macluritid gastropod, Macluritella stantoni Kirk, 1927 from the Lower Ordovician of Colorado, has revealed that its early whorls are openly and dextrally coiled, in contrast to those in later teleoconchs which are sinistrally coiled. This is the first documentation of heterostrophic coiling in members of the Macluritoidea, which have been considered to be dextrally hyperstrophic. Juvenile M. stantoni may be interpreted as dextrally orthostrophic and, thus, it had the same type of soft-body-shell arrangement as the vast majority of living and fossil gastropods. This intepretation also suggests that the Macluritoidea evolved from the dextrally orthostrophic gastropods, and their dextral hyperstrophy is derived and not a primary feature. In addition, occurrence of shell heterostrophy in M. stantoni brings additional evidence that the Macluritoidea and Onychochiloidea are not closely related taxa. Relationships between the Macluritoidea and Euomphaloidea are still uncertain. This study provides the oldest evidence (Early Ordovician) for shell heterostrophy in the class Gastropoda.

Madrynomya bruneti n. gen. and sp. is an undescribed bivalve collected from the late Miocene Puerto Madryn Formation in northern Patagonia. The specimens were collected together with other generally well-preserved mollusks from a parauthochtonous assemblage within a fine-grained sandstone. Based on their unique shell morphology, the specimens are placed in the Modiomorphoidea, a group of bivalves known only from the Paleozoic and Mesozoic. This conclusion is based on comparisons with other bivalve taxa such as Mytiloida, Dreissenidae, Modiomorphidae, Hippopodidae, and Anomalodesmata, which they resemble in different morphological features. However, careful inspection of key characters suggests that none of them are closely allied to this new genus, and placement in the Modiomorphidae is only tentative until more material is found and further characters, such as shell microstructure, can be properly analyzed. Likewise, an accurate reconstruction of this bivalve's life habit is presently impossible to determine with the two available specimens, but an endobyssate mode is probable, as has been inferred for Myoconcha.

Paleobiogeographic patterns of decapod crustaceans from the Southern Hemisphere, based upon 441 species-level records arrayed in 154 genera, document global patterns of distribution that can be compared to those previously published on decapods from the North Pacific and Central American regions. All known records of decapods from the Southern Hemisphere spanning the Early Triassic to Pleistocene have been compiled, nearly all have been personally verified, and patterns of origin and distribution have been interpreted. Interchange between hemispheres, including amphitropical and bipolar distributions, are recognized from Jurassic to post–Miocene time. The high southern latitudes was a site of origin of several generic-level taxa during the Jurassic through Eocene and many of these taxa have been identified in subsequent times in lower latitude regions in shallow- and deepwater environments in both hemispheres. The isolation of Antarctica due to ocean currents significantly diminished the role of the high southern latitudes as an area of origin for decapods. The Tethys was an important dispersal pathway for decapods during the Cretaceous through early Miocene. Endemism was high during the Eocene, similar to the North Pacific and Central America. The magnitude of the Cretaceous/Paleogene extinction event on the Southern Hemisphere decapod fauna was not profound; most Cretaceous extinctions seem to have occurred well before the end of the Cretaceous, and 85% of the Cretaceous families are known from the Paleogene in the Southern Hemisphere taxa.