Abundant and morphologically fairly diverse siliceous sponge spicules of Darriwilian (Middle Ordovician) age were collected from the Table Cove Formation of Port au Port Peninsula, western Newfoundland. Without co-occurrence of appropriate sponge body fossils, it is difficult to refer these disarticulated sponge spicules to existing or to new taxa. However, representatives of demosponges and hexactinellids are recognized. While marked differences are noted between older and younger lithistid dendroclones, for example, spicule form in these Middle Ordovician specimens is similar overall to previously known assemblages of various ages, demonstrating the morphologically conservative nature of the spicular skeleton.

Cambrian biotic zonation on the Siberian Platform reflects differentiation of the depositional environments (inner shelf, outer shelf and open basin). The combination of the chart of trilobite biofacies replacement and the curve of sea-level fluctuations shows that trilobite biofacies replacement occurs as a rule at times of sign reversal and distinct change in the rates of sea-level rise or fall. The boundaries of major Siberian platform Cambrian chronostratigraphic units, such a stages and series, frequently coincide with the boundaries of biofacies in stratigraphic succession related to sea-level fluctuations. If these fluctuations are gradual and restricted, then the boundaries of the Cambrian stages and series cannot be isochronous levels at a global scale. The known levels for intercontinental correlation on the Siberian Platform include boundaries of the adjacent Triplagnostus gibbus and Tomagnostus fissus Zones from the uppermost Amganian Stage (Middle Cambrian) and the Glyptagnostus stolidotus and Glyptagnostus reticulatus Zones of the lower Upper Cambrian. Both levels correspond to boundaries between highstands and lowstands on the Siberian Platform and appear to serve as boundaries of high rank. Evolution of the trilobite biofacies zonation is illustrated by genera typical for each of the various Cambrian paleogeographic environments on the Siberian Platform.

The Subulitoidea have long been an enigmatic group of Paleozoic gastropods and share many characters of post-Paleozoic clades. Newly described protoconchs from several late Paleozoic subulitoid species have been employed in a phylogenetic analysis of the group. Late Paleozoic representatives, the Soleniscidae, are caenogastropods with an unornamented orthostrophic larval shell. The Meekospiridae have a smooth blunt protoconch of about two whorls. In contrast to previous interpretations, this protoconch is not heterostrophic or heterostrophy is not obvious. Therefore, a placement of the Meekospiridae with the genus Girtyspira in the Opisthobranchia is to be treated with caution. The new lanthinopsis-like genus Imogloba has a gobular subulitid-like teleoconch but its protoconch consists of a smooth first whorl which is loosely coiled and a larval shell with a characteristic non collabral ornament. Therefore, a close relationship between Soleniscidae and Imogloba is unlikely and the new family Imoglobidae is proposed. We found no clearly heterostrophic groups within the late Paleozoic subulitoid gastropods. The phylogenetic analysis of all subulitoid genera with known protoconchs provides little support for the monophyly of the Subulitoidea, particularly for a close relation between the Meekospiridae and the Soleniscidae. However, the Soleniscidae and Meekospiridae are probably monophyletic groups. Most genera are restricted to the Paleozoic, although several Mesozoic genera may hold descendants of Paleozoic Subulitoidea. Finally, a hypothesized link between Subulitoidea and Neogastropoda based on the presence of an anterior notch in both groups is unlikely.

Trilobites assigned to 25 genera and 39 species are reported from the Crepicephalus Zone (Marjuman Stage) and Aphelaspis Zone (Steptoean Stage) in the lower part of the Deadwood Formation in the Black Hills of South Dakota. Six taxa are left in open nomenclature, and one new species, Glaphyraspis newtoni, is described.

Analysis of the lithologies for this interval from the best exposed measured sections on a southeast-northwest transect reveal a nearshore, shallow subtidal, siliciclastic dominated environment to the southeast, succeeded offshore by a shallow subtidal to lowest intertidal carbonate shoal environment, and then a transitional shaly limestone interval into a more shaly distal intrashelf basin to the northwest.

Specimens of species of Coosia, Crepicephalus, Tricrepicephalus, Kingstonia, Pseudagnostina, and Coosina comprise more than 75 percent of the fauna of the Crepicephalus Zone. Coosina ariston, Crepicephalus snowyensis, Tricrepicephalus tripunctatus, Arcuolimbus convexus, and some species of Blountia had a strong preference for the shallow-water siliciclastic facies present in the southeastern sections closest to the paleoshoreline. Crepicephalus rectus, Tricrepicephalus coria, Agnostogonus, cf. A. incognitus and the genera Coosella and Uncaspis preferred the farther offshore, deeper-water, shaly intershelf basin located in the northern Black Hills. Trilobites from the Crepicephalus Zone are used to correlate the lower part of the Deadwood Formation with coeval strata elsewhere in North America.

A new trigonotarbid arachnid, Gigantocharinus szatmaryi new genus and species, is described from Upper Devonian (Late Famennian) sediments in Pennsylvania. Devonian trigonotarbids were known before from only a single North American locality and several European ones. The new trigonotarbid occurs in what had previously been a significant time gap between the faunas of the Middle Devonian and the late Carboniferous. Gigantocharinus szatmaryi is assigned with some hesitation to the family Palaeocharinidae.

Well-preserved stem remains of the three crinoid species Qingyanocrinus kueichounensis (Dubatolova and Shao, 1959), Bangtoupocrinus kokeni n. gen. n. sp. and Silesiacrinus parvus n. sp. from the lower Upper Anisian (Middle Triassic) of Qingyan, Guizhou Province, southwestern China, are described. The former two taxa originally were described as one species, Entrochus rotiformis Koken, 1900, which is a nomen dubium. The two new genera Qingyanocrinus and Bangtoupocrinus are established. Bangtoupocrinus and Silesiacrinus are the earliest known millericrinid genera. For these Middle Triassic millericrinids, the new family Bangtoupocrinidae, comprising the new subfamilies Bangtoupocrininae and Silesiacrininae, is defined. The strongly cirrate genus Qingyanocrinus is assigned to the new family Qingyanocrinidae, whose systematic position is uncertain.

In all three species, the morphological features of the columnals characteristically vary in different parts of the stems. The millericrinids were cemented to (secondary) hard substrates by distal encrusting holdfasts. Qingyanocrinus kueichounensis most likely lived on soft substrates and for attachment made use of its rootlike distal stem end and cirri. Stems of Bangtoupocrinus kokeni regenerated after breakage show that these crinoids were able to continue living in spite of the traumatic loss of their basal fixation. Juvenile Encrinus cf. liliiformis Lamarck, 1801, and other invertebrates utilized the crinoids and their skeletal remains as substrates for attachment.

Although known previously from only two specimens from northern Greenland, new material from Marjuman boulders in debris flows of the Cow Head Group of western Newfoundland demonstrate that Verditerrina Robison is a menomoniid trilobite that is closely related to Hysteropleura Raymond. Following a parsimony analysis using the PAUP program, Verditerrina is used at the subgeneric level to label a distinctive monophyletic group within Hysteropleura. Three new species are established for the Newfoundland material: Hysteropleura (Verditerrina) adraini, H. (V.) edgecombei and H. (V.) ramskoldi. All three species undergo substantial modification of the anterior border of the cranidium during holaspid ontogeny. Two of the species, H. (V.) adraini and H. (V.) edgecombei, develop elongate, tongue-like borders that are reminiscent of those of calymenids such as Spathocalymene Tillman.

Halobia daonellaformis new species is described from the lowermost Carnian of northeast British Columbia. Halobia daonellaformis n. sp. is regarded as a primitive Halobia characterized by external ornamentation similar to Daonella lommeli, but with a poorly developed anterior auricle. Morphologic characters of H. daonellaformis n. sp. suggest that Halobia may be not a natural taxon but a polyphyletic group with one or more ancestors from Daonella and Aparimella and/or other posidoniid(s). The sudden appearance of Halobia throughout the marine Triassic suggests a rapid dispersal mechanism following a Ladinian origin. Larval shell morphology indicates a planktotrophic developmental strategy for H. daonellaformis n. sp., and by extension to other halobiids, which may explain the widespread distribution of many halobiid species.

A new species of the unusual dinoflagellate cyst genus Geonettia de Verteuil and Norris, 1996a is here described from the Pliocene of the western North Atlantic and eastern England. Geonettia waltonensis new species is only the second species to be formally described for this genus, whose type, G. clineae de Verteuil and Norris, 1996a, has a range of Miocene through Pliocene. Geonettia is a gonyaulacalean, goniodomacean genus of the subfamily Pyrodinioideae and is closely related to Eocladopyxis Morgenroth, 1966 and Capisocysta Warny and Wrenn, 1997, also found in the Cenozoic. However, Geonettia is the only known dinoflagellate cyst genus to have plates that dissociate extensively on both epi- and hypocyst during excystment. Geonettia waltonensis has this style of excystment, but its hypocystal tabulation is more akin to Capisocysta lata Head, 1998a than to G. clineae. Comparison of tabulation and other morphological features suggests that during the late Miocene, Capisocysta lata evolved from Geonettia waltonensis or a closely related species through failure of its epicystal plates to dissociate. Geonettia waltonensis probably did not evolve directly from G. clineae but may represent a separate lineage within Geonettia that arose during the Miocene.

A new genus and species of clawed lobster, Jagtia kunradensis, is described from the Upper Cretaceous (Upper Maastrichtian) Kunrade Limestone facies of the Maastricht Formation, The Netherlands. Three nephropid lobster genera and at least three species (Oncopareia bredai Bosquet, 1854, sensu Tshudy, 1993, Oncopareia sp. Tshudy, 1993, Hoploparia beyrichi Schlüter, 1862, and Jagtia kunradensis) have now been collected from limestones of the Maastrichtian type area (southeastern Netherlands and northeastern Belgium). Cladistic methods were employed in re-evaluating the phylogenetic relationships of the nephropid lobsters, including Jagtia. These analyses indicate that Jagtia is part of a clade that includes the recent Thymops and Thymopsis. The new genus is the first fossil form to be closely allied with these deep-water genera.

Stromatoporoids from the Brassfield Formation (Early Silurian, Llandovery) near Fairborn, Ohio, provided substrata for a diverse epizoic community. The stromatoporoids were colonized by at least 28 taxa, including bryozoans, cnidarians, echinoderms, annelids, and endolithic organisms. Analysis of the occurrence, diversity, distribution, and coverage of the epizoans recognized patterns of site-selective attachment on the surface of the stromatoporoids.

The upper surface of the stromatoporoids had a slightly higher total epizoan coverage than the lower surface. Concentric zones outlined from the margin also had differences in area and percent coverage. On the upper and lower surfaces, epizoan occurrence decreased from the margin to the interior. Epizoan coverage for the lower surface also decreased inward. On the upper surface, the middle zone had the highest coverage followed by the outer and polar zones, respectively. Among the major invertebrate phyla, only the echinoderms were randomly distributed. Bryozoans, cnidarians, and miscellaneous taxa including borers, cornulitids, and spirorbids were distributed nonrandomly on the surface of the stromatoporoids.

Over 95 percent of the stromatoporoid area analyzed is not covered by epizoans. However, epizoans are commonly clumped or in direct contact with one another. These physical interactions are the result of site-selective attachment by epizoans in close proximity rather than competition for available space.

Twelve ptychopariid species assigned to five genera occur in the Lower-Middle Cambrian boundary interval, Pioche Shale, eastern Nevada. New taxa include one genus, Eokochaspis, and seven species, Eokochaspis nodosa, E. delamarensis, E. metalaspis, E. longspina, Kochina? walcotti, Mexicella antelopea, and M. robusta. Two new biozones, the Eokochaspis nodosa and overlying Amecephalus arrojosensis Biozones, are proposed between the Lower Cambrian Olenellus Biozone and the Middle Cambrian Plagiura-Poliella Biozone. In addition, the three remaining informal shale members of the Pioche Shale are formally named.

Saffordophyllum newcombae Flower, 1961, displays unique abilities and an unprecedented range in types of corallite increase. Cerioid growth was characteristic, but colonies on soft substrates could grow in a tollinaform manner during early astogeny. The capacity for recovery from damage and partial mortality is amazing. Rejuvenation may have been accompanied by peripheral expansion in some cases. Rapid regeneration could involve axial increase. Circular lacunae that formed during recovery became sites of rapid lateral increase or corallite decrease.

Two types of axial increase occurred within coralla. Lateral increase was concentrated mainly along the basal wall and adjacent to certain circular lacunae. In typical cerioid parts of the corallum, lateral increase seldom yielded “adult” corallites, but incipient lateral offsets could be numerous. The level of colony integration was probably moderately high. There was likely soft-tissue continuity among polyps, coordination of polyp behavior, subjugation of individuals for the good of the colony, and perhaps astogenetic control.

Saffordophyllum newcombae is considered to be a tabulate coral, although one type of axial increase is similar to that in a few rugose corals and the other type of axial increase as well as possible peripheral expansion resemble modes of increase in some coralline sponges. Lateral increase is considered compatible with cnidarian rather than poriferan biology. Corallite size is typical of tabulates. Saffordophyllum may not be the direct ancestor of favositid tabulates, and may not even be closely related to them; S. newcombae is very different from Paleofavosites and Favosites.

The remarkable range in forms of increase discovered in S. newcombae demonstrates the critical need for detailed paleobiologic studies, if we are to understand the early evolutionary history of corals and to establish reliable criteria for distinguishing various coral groups and homeomorphs.

Analysis of dorsal carapace characters of fossil and extant genera of the Calappidae sensu lato supports Bellwood's (1996) assignment of the group into four families based upon phylogenetic analysis, which was also supported by previous larval and morphologic studies. The Calappidae sensu stricto, Matutidae, and Hepatidae, recognized by Bell wood (1996), embrace both fossil and extant genera. The Orithyiidae is known from a single extant genus. Additionally, the Necrocarcininae Förster, known only from extinct genera, is elevated to family status. New taxa include Mursia aspina and Eriosachila rossi. Zanthopsis rathbunae Kooser and Orr, 1973, is here referred to Eriosachila orri, n. comb, and nomen novum. Emended descriptions are given for Mursia yaquinensis Rathbun, 1926, and Necrocarcinus hannae Rathbun, 1926. Biogeographic analysis indicates that each family has a distinct origination and dispersal history independent of the other families. Ecologic information for each group suggests that climatic preferences for the extant families have either remained relatively stable since the appearance of each family in the Tertiary or were broader in the past.

The trilobite genus Jujuyaspis Kobayashi, 1936, an index fossil of earliest Ordovician age, is recorded from the Yosimuraspis Zone of the Mungok Formation (Lower Ordovician) for the first time in Korea. The Yosimuraspis Zone comprises Yosimuraspis vulgaris Kobayashi, 1960; Jujuyaspis sinensis Zhou in Chen et al., 1980; Elkanaspis jilinensis Qian in Chen et al 1985; and pilekid genus and species indeterminate. Closely comparable faunas to the Yosimuraspis Zone are well represented in North China. The occurrence of Jujuyaspis allows the correlation of the Yosimuraspis Zone with the earliest Ordovician faunas of North America, South America, and Scandinavia, and suggests that the Cambrian-Ordovician boundary in Korea be placed at the base of the Yosimuraspis Zone.

Several localities within the heterolithic facies of the St. Lawrence Formation (Upper Cambrian) of Wisconsin and Minnesota yield specimens with phosphatic exoskeletons, quadrate cross sections composed of four equidimensional faces each bearing a midline, and possible holdfast attachment during life. These specimens are here referred to the order Conulariida, class Scyphozoa. Their fine, tuberculate surface ornament and serially invaginated midline structure serve to define a new genus, Baccaconularia, to which two new species, B. robinsoni and B. meyeri, are assigned. Conularia cambria Walcott 1890, also from the Cambrian of the northern Mississippi Valley and long dismissed as a misidentified trilobite fragment, is illustrated photographically for the first time. This species occurs in rocks stratigraphically beneath the St. Lawrence Formation. Specimens assigned to this species by Walcott are conulariids, but lack features now considered diagnostic of either Conularia or Baccaconularia. Walcott's material is insufficient to permit detailed taxonomic evaluation, and we isolate this name to this material, pending the collection of additional, better preserved specimens. Together, Baccaconularia and Conularia cambria contain the oldest large conulariids, and these narrow a stratigraphic gap between other large conulariids known from the Lower Ordovician onwards, and smaller fossils with conulariid affinities known only from Lower Cambrian rocks.

In the first broad survey of skeletal crystallography in fossil crinoids, we examine 10 Ordovician species representing five orders and apply crystallographic data to questions of crinoid phylogeny, homology, and development. Orientations of c crystallographic axes in the large calcite crystals that form the skeletal plates of the crinoid calyx vary systematically according to the position of each plate on the calyx. Plates lower on the calyx have axes more inclined toward the stem attachment than are axes from plates higher on the calyx. Although most specimens display this general pattern, exact orientations vary widely between species with no discernible relationship to phylogeny. Furthermore, the topological pattern of variation does not correlate with the order of addition of plates to the calyx during growth.

Lack of a phylogenetic signal among diverse crinoids early in the clade's history implies that crystallographic data will be of limited use to high-level phylogenetic studies within crinoids. Neither does skeletal crystallography strongly favor any of several competing interpretations of homologies among major crinoid calyx plates. Crystallographic data are informative, however, for some minor skeletal plates. Brachial plates have c axes that roughly parallel the surface of the plate, whereas interbrachial plates have perpendicular c axes, suggesting that distinct generative processes produce these plates. Anal plates have orientations similar to interbrachials, suggesting similar developmental mechanisms.

Although c axes have regular orientations relative to plate morphology within a specimen, a axes show extensive intraspecimen variability with respect to plate morphology.