The terminal Neoproterozoic Sheepbed and Blueflower Formations at Sekwi Brook in northwestern Canada have yielded two additional taxa, both of them new to North America. Hiemalora cf. H. pleiomorphus Vodanjuk is a tentaculate disc that most likely represents a semi-infaunal polyp. Windermeria aitkeni n. gen. and sp. is an ovate, bilaterally symmetrical, segmented fossil similar to the dickinsoniids; these fossils characterize Neoproterozoic faunas of Australia and the Russian Platform, but had not previously been reported from Laurentia.

A preliminary survey of benthic invertebrates off central west Florida provides documentation of modern epifaunal communities on a low-gradient carbonate slope. Three large-scale biofacies occur in soft-sediment carbonate environments between 200 and 2,000 m: an Echinoderm biofacies (200–550 m) dominated by a diverse assemblage of echinoderms, gastropods, and decapod crustaceans; a Penaeid shrimp–conical mound biofacies (550–1,200 m) characterized by large bioturbation structures; and a Microbial mat biofacies (1,200–2,000 m) with only rare epifaunal invertebrates. A fourth, hard-substrate biofacies reflects the presence of localized Miocene and Pleistocene hardgrounds in water depths of 200–600 m. This illustrates that hard-substrate biofacies may be laterally correlative with soft-sediment biofacies in a slope setting, thus producing a mosaic of contrasting faunal associations. All four biofacies have low population densities, presumably as a consequence of relatively low surface productivity. All four biofacies also show biogeographic affinity with other faunas at intermediate depths in the Caribbean region. Depth-related faunal transitions on the west Florida slope correlate with substrate and current velocity. Decreasing species diversity and abundance and a biofacies transition from suspension-feeding to deposit-feeding assemblages correlate with increasing depth, a decrease in mean grain size, and an increase in organic content of the sediment. This biofacies model may provide a modern analogue for faunas of ancient low-gradient slopes such as those of Cretaceous “shelf-sea” chalks of northwestern Europe.

The poorly known type species of Acrotreta, A. subconica Kutorga, 1848 [=Spondylotreta faceta Gorjansky, 1969], is redescribed and a neotype selected from the lower Arenig (Billingen Stage, Oeland Series) Päite beds in the environs of St. Petersburg (Tosna river), Russia. Acrotreta is also the type of the lingulate brachiopod family Acrotretidae Schuchert, 1893, and order Acrotretida Kuhn, 1949. Four new species are described: A. korynevskii from the upper Tremadoc–lower Arenig, South Ural Mountains; A. tallinnensis from the upper Arenig (Volkhov Stage), Tallinn, northern Estonia; A. nobilis from the Llanvirn (Kunda Stage), Siljan district, Sweden; A. cooperi from the Llandeilo, Alabama, USA. Acrotreta has many features in common with Spondylotreta Cooper, 1956. The type species of the latter, S. concentrica Cooper, 1956, from the Llandeilo Pratt Ferry beds at Pratt Ferry, Alabama, is refigured.

Cryptonella? cailliaudi Barrois, 1889, from the Lower Devonian of the Armorican Massif, is tentatively assigned to the athyridid brachiopod genus Planalvus Carter, thus far known only from the Lower Carboniferous of eastern North America. In addition, a new species, Planalvus rufus, is described from the Bois-Roux Formation (Pragian) of Brittany, France. These French species are small brachiopods with complex spiralial and jugal structures, which permit assignment to the order Athyridida.

The widespread occurrence and local abundance of corbulid bivalves in Neogene deposits of the northern Dominican Republic provide an opportunity to evaluate physical controls on species distributions and intraspecific variability in this group. First and last appearances of species probably do not record speciation and extinction, but instead represent migrations into and out of the study area, and reflect corbulids' preference for marginal-marine and shallow-marine conditions. Corbula cercadica and C. viminea show patterns of intraspecific morphologic variability over time and space. Corbula cercadica shows continuous morphologic variability along a paleoenvironmental gradient of salinity, depth, and bioclastic fabric, whereas variation in C. viminea is morphologically clinal from west to east in roughly contemporaneous sediments, with variability related to sediment type and bioclastic fabric. Ecophenotypic variation or genetic differences, rather than taphonomic processes, seem to control geographic variability within C. cercadica and C. viminea. Although it is not possible to determine whether intraspecific morphologic variability was under genetic control, its stronger relationship with paleoenvironmental conditions relative to stratigraphic position suggests lack of anagenetic morphological evolution.

Gastropods are abundant in the Middle Ordovician (Whiterockian) Antelope Valley Formation of Nevada. Because Whiterockian rocks are absent in much of central and eastern North America, these Nevada gastropods play a significant role in understanding the Early to Middle Ordovician transition of the class. The shell and operculum of a new genus and species of macluritoid, Monitorella auricula, is described. New euomphaloid taxa include Walcottoma frydai n. gen. and sp., Rossospira harrisae n. gen. and sp., Barnesella measuresae n. sp., Helicotoma gubanovi n. sp., Lytospira yochelsoni n. sp., and Malayaspira hintzei n. sp.

In a large collection of Wenlockian gastropods from north Siberia, a single small specimen shows the operculum in situ just within the aperture. In other morphologic features, particularly the presence of numerous spiral lirae on the shell, this species is similar to Silurian gastropods traditionally assigned to Oriostoma. Preservation of the operculum is far from perfect, but almost certainly it has paucispiral growth, rather than concentric or multispiral construction. This new species (Australonema varvarae n. sp.) is assigned to Australonema, previously known only from the Lower Devonian of Australia, primarily because of the form of the operculum. The material was obtained from just below a biostromal unit in a bed interpreted as an interreef lagoon in an area of locally relatively quiet water.

It has been proposed previously that the northern Mississippi Valley Sunwaptan trilobite genus Dikelocephalus comprises 26 species. Morphometric analyses demonstrate that many of the criteria that had been used to define species of Dikelocephalus are invalid and additional analysis of biostratigraphically and biogeographically constrained collections is necessary before the taxonomic status of Dikelocephalus can be fully resolved. Our results indicate that infrageneric morphological variation in Dikelocephalus is continuous and lacks gaps that could be the basis for establishing multiple species. Many of the characters shown to be taxonomically insignificant in Dikelocephalus are also widely used in the definition of other trilobite taxa. This suggests that the species-level taxonomy of many trilobites may be substantially oversplit. Recognition of widespread oversplitting will have important consequences for biostratigraphic zonations, paleogeographic distributions, and estimates of taxonomic diversity.

Three new species of trilobites, Erixanium lacunatum, Cernuolimbus monilis, and Anechocephalus aphelodermus, have been recovered from two new fossiliferous localities in the normally unfossiliferous Collier Shale in the Ouachita Mountains of west-central Arkansas. These new taxa occur with other trilobites previously reported from the Elvinia Zone in the Collier and elsewhere. Like the other trilobites reported from the Collier, these new taxa were originally deposited on the outer shelf, and were later eroded and redeposited in the adjacent, deep-water basin. Other species assigned to these genera have also been reported from outer shelf or continental slope sites. Species of Erixanium were widely distributed in equatorial and subtropical paleolatitudes in the Late Cambrian.

Protaspides and later growth stages are described and discussed for the Ordovician trinucleid trilobite Cryptolithus tesselatus Green and the raphiophorid Lonchodomas chaziensis Shaw. A small triangular rostral plate is described for a single protaspid instar in both Cryptolithus and Lonchodomas. The presence of this small sclerite in the ontogeny of these taxa supports the origin of the Trinucleoidea from the Ptychopariida through reduction in and then fusion or loss of the rostral plate. Earlier and later growth stages have fused ventral sclerites, with no signs of connective sutures. All members of the Trinucleoidea with known ontogenies share similar small, ovoid asaphoid protaspides, with distinct axes and varying numbers of sharp, conical to subtubular, submarginal spines on the dorsal exoskeleton and marginal spines on the hypostome. Two protaspid instars are identified in both Cryptolithus and Lonchodomas, sharing many characters that indicate homologous levels of development. A single origin for the median suture of the Asaphida is supported, with an anterior rostellum as its precursor.

Dimeropyge öpik, 1937, is a genus currently composed of at least 14 similar Middle (predominantly) to possibly lowest Upper Ordovician species from Laurentia (13 species) and Baltica (one species). Possible Lower Ordovician specimens have been illustrated by Ross (1951). Dimeropyge clintonensis Shaw, 1968, is redescribed, based upon additional material of mature topotypes. A new species of Dimeropyge, D. speyeri, is proposed for material from the Esbataottine Formation in the Mackenzie Mountains, northwestern Canada, previously described as D. clintonensis. A phylogenetic analysis of 10 of the 14 species of this genus is presented (the other species are less completely known, and are related to the analyzed species in a more traditional manner). Ontogenies from protaspid to holaspid stages are provided for D. clintonensis, D. speyeri, and D. virginiensis Whittington and Evitt, 1954. The larval stages of these species are very similar, supporting the close relationship between species assigned to Dimeropyge.

Alcymene n. gen. comprises a monophyletic group of calymenids known from the Ludlow Series of Sweden and the British Isles. The sister species Alcymene alveus and A. lindstroemi n. gen. and spp. (Hemse Beds, Gotland, Sweden) are most closely related to the type species A. neointermedia (Richter and Richter), which occurs in overlying and underlying strata at nearby localities. Structural modification of A. alveus and A. lindstroemi, especially the development of a greatly broadened and troughed librigenal border, can be interpreted as “snowshoe” adaptations for increased stability on an offshore mud substrate.

Five species of camerate crinoids from the Middle Ordovician Dunleith Formation (Galena Group) of northern Iowa and southern Minnesota are described: Cleiocrinus regius Billings, Cotylacrinna sandra n. gen. and n. sp., Euptychocrinus skopaios n. gen. and n. sp., Abludoglyptocrinus charltoni (Kolata), and Eopatelliocrinus ornatus (Billings) n. comb. Archaeocrinus desideratus Billings is assigned to Cotylacrinna, and Glyptocrinus fimbriatus Shumard and Ptychocrinus longibrachialis Brower are placed in Euptychocrinus. The geographical affinities of the Iowa and Minnesota crinoids lie with adjacent localities in the northern midcontinent and the Appalachian province of Canada and New York. Preservation of various specimens implies that Euptychocrinus skopaios, Abludoglyptocrinus charltoni, and Eopatelliocrinus ornatus utilized parabolic arm fans. Cotylacrinna sandra is a specialized rhodocrinitid which is perhaps the largest completely known Ordovician crinoid with a stem length of over 91 cm and a total volume of about 45,740 mm3. The root morphology indicates an upright column and this animal towered above the associated echinoderms, which ranged from the substrate level to a maximum of 25 cm above the seafloor. Euptychocrinus skopaios is marked by dwarfed morphology compared to the closely allied E. fimbriatus, and it exhibits accelerated development of fixed brachs, number of brachials in and length of the arms, and closely spaced pinnules. The dwarfism is interpreted as a specialization for small size and adults of E. skopaios were only located about five or six cm above the substrate. New brachials and pinnules form at the distal arm tips of E. skopaios throughout ontogeny. Consequently, the length of and the number of plates in the food-gathering system are positively allometric relative to the crown volume. Food gathering capacity equals the number of food-catching tube feet times width of the food grooves and it is also augmented more rapidly than expected for an isometric crinoid. Although distantly related to euptychocrinids, most other Dunleith camerates, namely Abludoglyptocrinus charltoni, Eopatelliocrinus ornatus, and Cotylacrinna sandra, follow the same developmental trends of the food-gathering system observed in Euptychocrinus skopaios. Comparison of the pinnulate camerates and three species of ramulate cladids and a disparid from the Dunleith reveals some striking contrasts. At equivalent crown volumes, the camerates are characterized by more numerous arm branches in the form of pinnules, more narrow food grooves, more closely spaced tube feet, and longer food-gathering systems with more plates and greater capacity. The Dunleith camerates were adapted for catching smaller food particles using more numerous and more closely spaced tube feet located on more extensively branched filtration nets than the associated cladids and disparid. The differences can be attributed to taxonomy and presumably phylogeny, that is camerates versus cladids and disparids, and/or morphology in the presence of pinnules versus ramules.

Samples from the Dumugol Formation were collected from eight measured sections and two cores in the so-called Baegunsan Syncline, located between eastern Yeongweol and Samcheog areas, Kangweon-Do, South Korea. A total of 7,813 identifiable conodonts were recovered from 146 samples. They are classified into 24 multielement species referable to 16 genera, and 37 form species belonging to 17 genera; six species are newly described: Distacodus dumugolensis, Parapanderodus acontiformis, Scolopodus longibasis, Scolopodus n. sp. A, Triangulodus dumugolensis, and Oistodus(?) sp. The Dumugol Formation is divided biostratigraphically into four conodont zones, viz, Chosonodina herfurthi-Rossodus manitouensis, Glyptoconus quadraplicatus, Paracordylodus gracilis, and Triangulodus dumugolensis zones in ascending order. These zones are correlated with those of the early Ordovician conodont faunas of North America, northern Europe, China, Australia, and Iran. The Dumugol Formation ranges from late Tremadocian to early Arenigian in age. The boundary between these two series lies between 70 and 100 m above the base of the Dumugol Formation in each of the sections.

Upper Devonian (Famennian) sequences were sampled at two sections in the Canning Basin, Western Australia, and a section at Bactrian Mountain, Nevada, over an interval ranging from the Upper crepida Zone into the Lower marginifera Zone of the standard conodont zonation for the Famennian. Over 30,000 conodont elements have been identified among 43 species and subspecies within six genera. New complete and partial multielement reconstructions are illustrated for: Palmatolepis falcata, P. glabra prima, P. loba, P. minuta minuta, P. perlobata perlobata, P. perlobata maxima, P. quadrantinodosalobata, P. rhomboidea, P. schindewolfi, P. subgracilis, P. wolskae, Polygnathus cf. P. diversus, P. glaber glaber, P. nodocostatus nodocostatus, P. subnormalis, and P. cf. P. triphyllatus. The reconstructions are based on stratigraphic occurrence, detailed morphologic similarities, and a few exceptional low-diversity faunas. Additionally, Palmatolepis adamantea n. sp. is proposed based on the Pa element.

A more precise understanding of the taxonomic boundaries of Palmatolepis is achieved through knowledge of the entire apparatus, rather than confined to the Pa elements. Reconstructions presented here provide a more comprehensive understanding of the range of morphologic variation that exists in Palmatolepis, and show that a single generalized elemental plan can be demonstrated for all members of the genus. The differences in the non-Pa elements can thus be used to refine taxonomy and increase understanding of phylogenetic relationships at the specific and subspecific level.

Skull bones of Gosfordia truncata Woodward, 1891, from the Lower Triassic Hawkesbury Sandstone of New South Wales, Australia, are described for the first time. The skull roofing pattern suggests possible affinities between G. truncata and Paraceratodus germaini (Triassic, southwest Madagascar). A three-dimensional reconstruction of the skull of Ceratodus formosus Wade, 1935, based on the holotype, found in a Lower Triassic deposit at Brookvale in New South Wales, is included. This reconstruction indicates that this species is not closely related either to the recent Australian lungfish, Neoceratodus forsteri, or to the Triassic Ceratodus (Tellerodus) sturii from Nord Alpen in Austria, and it has no close affinities with G. truncata. A new genus, Ariguna, is therefore proposed to receive Ceratodus formosus Wade, 1935. Without associated tooth plate material, G. truncata and A. formosa cannot be defined more precisely.

An amphibian trackway collected in minespoil from the Cross Mountain Formation in the Cumberland Mountains of East Tennessee represents the first known Middle Pennsylvanian (Westphalian) amphibian trackway from the southeastern United States. The tracks are impressed onto the upper surface of a bed of fine-grained, cross-laminated sandstone and siltstone, deposited in an upper delta plain environment.

The trackway was made by an amphibian with a long glenoacetabular distance and low pace-angulation. The imprints show five digits on the pes and four on the manus. Average measurements for the trackway are: stride, 8.4 cm; pace angulation, 76.1° (manus), 63.1° (pes); track width, 5.5 cm (manus), 6.7 cm (pes); glenoacetabular distance, 16.7 cm. The manus impression averages 2.8 cm long by 3.1 cm wide, and the pes averages 3.8 cm long by 3.1 cm wide. A tail drag is conspicuous along the entire length of the trackway and has a minimum radius of curvature of 9 mm.

The trackway is assigned to Matthewichnus caudifer n. ichnosp. on the basis of similarities to published material. The trackmaker was probably a temnospondyl labyrinthodont, considering the size of the animal (thus excluding lepospondyls) and the fact that it had a four-digit manus (thus excluding reptiles and anthracosaurian labyrinthodonts).

Palynoflorules containing sparse but regularly occurring chitinous-walled fungal, probably ascomycete, spores have been obtained from silty limestone nodules in the Jurassic Coon Hollow Formation in the Wallowa terrane in Hells Canyon, Idaho. The fungal spores are associated with moderately abundant embryophytic spores and pollen that suggest late Early Jurassic to early Middle Jurassic age, which agrees with dating provided by marine animals stratigraphically just above. The fungal spores constitute the most diverse such assemblage of robust-walled spores described from pre-Cretaceous rocks. Two new species of the fossil fungal spore form-genus Diporicellaesporites, D. idahoensis and D. serratulus, and one new species of form-genus Fractisporonites, F. pittsburgensis, are described.

During the 1991 ostracodologists' symposium in Australia, I heard a young man in the seat across the aisle tell his companion, “I hope that my new species will never be placed in synonymy.” I turned to him and explained that there is neither shame nor crime in having a species placed in synonymy by another scientist.

The purpose of this note is to point out the similarities between Protosalvinia (Foerstia) and Sidetes (Spathiocaris) and to discuss characters that can be used to distinguish the two taxa. Protosalvinia Clarke, 1885 (Figure 1.1-1.4), also commonly referred to by the junior subjective synonym Foerstia, is a plant fossil that is frequently noted as occurring in Upper Devonian black shale sequences of North America. This taxon has been of great interest to stratigraphers, paleoecologists, plant taxonomists, and plant morphologists over the years (see, for example, Winslow, 1962, p. 7, p. 22, fig. 3; Barron and Ettensohn, 1981, p. 30-31; Matthews, 1983; and Romankiw et al., 1988). Most workers in recent years have considered Protosalvinia to be a marine alga, but there is also evidence for a land plant affinity (Romankiw et al., 1988).