A bed on Jbel Issoumour, near Alnif in southeastern Morocco, contains numerous complete trilobites. The bed is located stratigraphically at the base of the El Otfal Formation, immediately above a cliff-forming resistant unit known to local trilobite miners as the ‘grand calcaire’, and is latest Emsian or early Eifelian in age. The fauna exhibits an alpha trilobite diversity of at least eight species, including Erbenochile issoumourensis n. sp., Acanthopyge (Lobopyge) bassei n. sp., and Walliserops lindoei n. sp. The absence of lateral palpebral extensions in E. issoumourensis but their presence in the type species of Erbenochile, E. erbeni, when considered with other differences in the exceptionally large eyes of both species, supports the hypothesis that these palpebral structures functioned as eyeshades in E. erbeni but not in E. issoumourensis. Walliserops lindoei has a short, stout haft at the base of the trident anterior cephalic projection, which is the most characteristic feature of Walliserops. This projection in Walliserops primarily functioned as a deterrent to predators.

New material, including a complete exoskeleton, from the Bromide Formation of Oklahoma, allows a complete evaluation of Probolichas Phleger, 1936 and necessitates a quantitative revision of the lichid tribe Tetralichini Phleger, 1936. A strict consensus tree of nine equally parsimonious trees generated from a branch and bound analysis indicates that the genus Probolichas is monophyletic, and should no longer be restricted as synonymous with, or as a sub-clade of Amphilichas Raymond, 1905. The genus Apatolichas Whittington, 1963 is revised as a synonym of Amphilichas, and the Tetralichini is defined as clade with three genera: Amphilichas, Probolichas, and Lyralichas Weber, 1948. Probolichas kristiae from the Bromide Formation and Amphilichas effnensis from the Effna Formation of Virginia are new species.

The Batocrinidae was a component of the North America Early Mississippian crinoid fauna and a significant contributor to the global biodiversity spike referred to as the “Age of Crinoids.” All batocrinids are North American, and all but one species are confined to the Tournaisian and Visean. In this contribution, genera are objectively defined on discrete characters, and the generic assignment of all valid species is re-evaluated. A phylogenetic hypothesis is presented for relationships within the Batocrinidae based on parsimony-based analyses and known stratigraphic ranges.

Fifteen basic batocrinid architectural designs are recognized as genera, and four new genera are described: Glannearycrinus n. gen., Gongylocrinus n. gen, Magnuscrinus n. gen., and Simatocrinus n. gen. Batocrinus was a catch-all genus for any Mississippian camerate with tetragonal first primibrachials and an anal tube; thus, many late 19th century species are in need of a modern generic assignment. In this contribution, 61 percent of the 166 currently valid batocrinid species are reassigned to different genera. In addition, Sunwaptacrinus is transferred to the Batocrinidae, six species are transferred out of the Batocrinidae, and five species are designated as nomina dubia.

A phylogenetic analysis was conducted to address evolutionary relationships among the earliest members of the Miacidae (one of two early Cenozoic carnivoran families) and to ascertain the position of an ambiguous taxon, “Miacis” jepseni, with respect to the genera Miacis, Uintacyon, Vulpavus, Vassacyon, and Oödectes. The results of this analysis indicate that “Miacis” jepseni should be referred to the genus Oödectes, and both genus and currently included species are rediagnosed. The phylogenetic relationship of Oödectes to other miacids, and relationships among early Eocene miacids more generally, however, are less well resolved. Support is found for sister taxon relationships between Miacis and Vulpavus and between Uintacyon and Vassacyon, and it is suggested that this latter clade is the sister taxon to all other members of Miacidae.

The third species belonging to Zygastrocarcinus from the Cretaceous of the Western Interior is represented by a single carapace collected from below the Groat Sandstone Bed, Gammon Ferruginous Member, Pierre Shale of Carter County, Montana. Comparison of Zygastrocarcinus cardsmithi n. sp. with the other North American congeners, Z. mendryki (Bishop, 1982) and Z. griesi Bishop, 1983, and with the Pacific Slope species Z. richardsoni (Woodward, 1896) suggests early separation of the Pacific Slope and Western Interior lineage having Z. cardsmithi as a possible ancestor to Z. mendryki and Z. griesi.

A distinctive new genus (Xyoeax) and two new species (Xyoeax eponcus, Scutellum sudorum) of styginid trilobites are described from the late Early Devonian (Emsian) Murrindal Limestone of eastern Victoria, Australia. Limited material of a third styginid species not belonging to any named genus is also described from the same locality. Xyoeax is considered to be closely related to Ancyropyge Clarke, 1891, and Weberopeltis Maksimova in Moore, 1959, and less closely related to Kolihapeltis Prantl and Přibyl, 1947. Weberopeltis is revised and newly diagnosed. Several species previously assigned to Weberopeltis are transferred to the new genus Exastipyx, which is considered to be related to Cornuscutellum Snajdr, 1960. Ancyropyge, Exastipyx, Weberopeltis, and Xyoeax all have pygidia with long pleural spines derived by reduction of the pleural field between the pleural ribs, whereas Kolihapeltis and Cornuscutellum lack pygidial spines. Pygidial morphology of Xyoeax type has thus arisen independently in separate styginid lineages. The type species of Altaepeltis Maksimova, 1968 is established as Weberopeltis bublitchenkoi Maksimova, 1960, by monotypy.

A new Tertiary gastropod genus, Peonza n. gen., is described, along with two new species, P. torquata from southern Argentina and P. benjamina from southern Chile. These muricacean gastropods, of uncertain familial status, occur in the late Eocene San Julián Formation and in the late Oligocene to early Miocene? Monte León Formation, Santa Cruz Province, Argentina. They also were recorded in the (probably) Oligocene Magellanian beds in Tierra del Fuego, Argentina, and in early Miocene deposits of the Tres Montes region in the Chilean Canals. In spite of the small number of specimens, Peonza n. gen. seems to have had a wide geographic and temporal distribution.

A deep core from Warren County, Ohio, has yielded numerous fossils of Cambrian age. The specimens, which are among the first recorded from Cambrian rocks of Ohio, suggest revisions in the inferred ages of the Eau Claire and Mount Simon Formations in the Cincinnati Arch region. Trilobites indicative of Dresbachian (late Middle Cambrian to early Late Cambrian) and possibly Franconian (Late Cambrian) age are present in the upper Eau Claire Formation. By implication, the underlying Mount Simon Formation must be of earlier Dresbachian age or perhaps older. Identified trilobites from the Eau Claire Formation seem to be characteristic of inner-shelf lithofacies of Laurentia. Other body fossils from the Eau Claire Formation include inarticulate brachiopods and a graptolite. Body fossils in the lower Knox Dolomite include trilobite sclerites and echinoderm ossicles. Trace fossils are present in both units.

Predatory drillholes (boreholes) are known from fossils as old as the late Precambrian (Bengtson and Zhao, 1992). The presence of predatory drillholes has been documented in a large number of shelly invertebrates including bivalves, gastropods, scaphopods, crabs, ostracodes, brachiopods, and many others (e.g., Sohl, 1969; Bishop, 1975; Bromley, 1981; Vermeij, 1987; Kabat, 1990; and references therein). We document here, for the first time, a drillhole in a lingulid brachiopod.

Previously undescribed specimens of Pachycephalosaurus wyomingensis allow partial description of the anterior braincase and a preliminary examination of change of dome shape with age. The two morphs of dome shape recognized in adults are also present in juvenile specimens with dome lengths half that of mature adults. A new specimen of Stegoceras edmontonense in the same geographic and stratigraphic provenance as P. wyomingensis establishes that the two pachycephalosaur genera could exist sympatrically.

Onset of maturity in trilobites is generally considered to occur when the last trunk segment is released into the thorax, marking the start of the holaspid stage. Here we describe striking morphological changes that occur within the holaspid ontogeny of Lonchopygella megaspina Zhou in Zhou et al., 1977, which include the effacement of dorsal furrows, the rapid and complete degeneration of pygidial lateral spines, and the increasing prominence of a pygidial axial spine. These notable changes, which are not coincident with the onset of the holaspid phase, emphasize that the onset of maturity in trilobites should be viewed on a character-by-character basis before assessing whether the exoskeleton as a whole can be described as mature. The holaspid pygidial condition in L. megaspina may represent an intermediate step in an evolutionary transition in the number, form, and allocation of segments in the tsinaniid trunk. Pygidial transition from a dynamically changing complement of segments in the meraspid phase to a static complement in the holaspid phase was accompanied by a marked change in the extent to which segment boundaries defined pygidial structure. Attaining this static complement allowed subsequent pygidial development to emphasize its structure as an integrated unit in which internal segmental boundaries became diffuse, a continuous margin to become prominent, and an elongated terminal spine, first evident at onset of epimorphic growth, to develop allometrically. Trilobite body development suggests that while the segmented construction placed constraints on how morphology varied, the influence of these constraints diminished following completion of thoracic segment construction. Selective premium for a distinct posterior tagma might favor the early ontogenetic acquisition of such a structure, and could have been a driver of the repeated trend toward caudalization witnessed among derived trilobite clades.

Two alternative hypotheses for proximal column growth are tested in Taxocrinus cf. T. whitfieldi, a late Mississippian flexible crinoid. The first hypothesis states that new columnals are added at the base of the proximal column (immediately above the generating columnal), whereas the second hypothesis has columnals of the proximal column inserted beneath the aboral cup. In both hypotheses, middle column columnals are inserted beneath the generating columnal and are independent from the proximal column.

External features used to determine points of columnal insertion include wedge-shaped columnals and sharp changes in columnar morphology. Sagittal sections reveal the presence of small columnals, some of which can be interpreted as the last columnals inserted prior to death. Data collected on Taxocrinus cf. T. whitfieldi confirm the first hypothesis. This hypothesis may be applicable to other crinoids with xenomorphic columns.

Dolostones of the upper Piauí Formation, Parnaíba Basin, northern Brazil, preserve a rich and diversified invertebrate fauna of Morrowan to Desmoinesian age. Among bivalves, Heteroconchia (15 species) is the most diversified, followed by Pteriomorphia (11 species), and rare endobenthic species of the Palaeotaxodonta (three species). Eleven species of Pteriomorphia are described, including representatives of the genera Parallelodon?, Myalina?, Septimyalina, Caneyella?, Leptodesma (Leptodesma), L. (Leiopteria), Meekopinna?, Aviculopinna?, and Aviculopecten. A new combination, Etheripecten trichotomus, and the oldest member of the Anomiidae recorded, Pindorama nordestina n. gen. and sp., also are described. Details of muscle scars and hinge characters have been recovered for several taxa, thereby refining the knowledge for species diagnoses. Fossil beds in the Esperança and Mucambo dolostones reveal episodic burial of bivalves in life position. These are internally complex, multistory fossil concentrations recording background and episodic processes. Hence, those fossil concentrations show high degrees of time-averaging and poor paleoecological resolution (except for the bivalves preserved in situ).

New Devonian (Frasnian and Famennian) crinoids are described from central and eastern Iran and a new Mississippian (late Tournaisian) echinoderm fauna is described from the south flank of the Alborz Mountains of northern Iran. Both the Devonian and Mississippian echinoderms were living in a carbonate shelf basin on the northern flank of Gondwana at approximately 30° south latitude.

The geographic ranges of Hexacrinites and Eutaxocrinus are extended onto the northern margin of Gondwana and add to the sparsely known Famennian crinoids. The Mississippian fauna is dominated numerically and in diversity by cladids, unlike most late Tournaisian faunas that are dominated by camerates in numbers, if not diversity. The late Tournaisian fauna is most similar to a coeval fauna from southern Iran, both of which have a noted lack of actinocrinitids and rare platycrinitids. It also shows similarity with Tournaisian faunas of western North America with four common genera.

New species introduced are: Hexacrinites persiaensis, Eutaxocrinus risehensis, Dichocrinus damghanensis, Amabilicrinus stellatus, Bridgerocrinus alborzensis, Bridgerocrinus semnanensis, Paracosmetocrinus mobarakensis, Decadocrinus clypeus, and Palaechinus iranensis.

Of all the morphologic characters used in favositid taxonomy, corallite size has most frequently been given more weight than others because of its relative ease of measurement and because it has been generally believed to be less variable. This study evaluates the reliability of corallite size as a criterion by a statistical treatment of several populations of favositids in the Upper Silurian West Point Reef Complex in Gaspé, Québec. Calculation of corallite cross-sectional area was made feasible by computer-based image analysis which provides a quick and accurate measure of size. The present study shows that the mean of the largest 10 percent corallite areas in mature parts of colonies with a minimum sample size of 100 corallites per cross section is the best approximation available of mean adult corallite size.

It is suggested that intraspecific variability of corallite size is often too large for this character to be used in practice, probably due to phenotypic plasticity. The same may be true of most other morphologic characters. In some cases, however, one or two characters remain invariate within a species and can be used diagnostically. The same characters may be extremely variable in other species.

Several specimens of the small hexactinellid, Cyathophycus mackenziensis n. sp., were collected from pale brown, shaly mudstone of the Road River Formation. The sponges are of Wenlock age and were collected from near Avalanche Lake, Mackenzie Mountains, Northwest Territories, Canada. The small, steeply obconical sponges have skeletons in crudely ranked quadrules to at least third-order, with first-order openings generally 2 mm high and 1 mm wide. Successive orders decrease in stages approximately half that of larger elements. A moderately irregular dermal(?) layer with circular parietal gaps is suggested in some specimens. The new species is consistently finer textured than either the type species Cyathophycus reticulatus Walcott, 1879, or the later described Cyathophycus quebecensis Dawson, 1889.

The Little East Lake Formation represents a spectrum of Late Ordovician (Ashgill) nearshore environments. These physical environments are characterized by a variety of quartz- and feldspar-rich sandstone and slate. Depositional environments include neritic nearshore, beach, tidal flat, and alluvial(?). The beach and neritic nearshore environments contain a variety of fossil invertebrates. The majority of the brachiopod fauna is confined to two taxa: Eodinobolus rotundus Harper, 1984, and Dalmanella testudinaria ripae Mitchell, 1978 (in Cocks, 1978). Some of the specimens have been broken and abraded suggesting transport within the beach swash zone. Gastropods include Lophospira cf. L. milleri (Hall), Lophospira(?), Trochonemella cf. T. notabilis (Ulrich and Scofield), and Daidia cerithioides (Salter). Tidal-flat environment contains the trace fossils Palaeophycus and Planolites.

The Late Ordovician (Caradoc and Ashgill) sedimentary basins developed subsequent to the collisional Taconian orogeny, wherein an arc accreted to the eastern Laurentian margin. Prior paleomagnetic reconstructions place the southeastern continental margin of Laurentia at approximately 25° south latitude during the Late Ordovician. Using these reconstructions, the siliciclastic Ashgill rocks discussed here would have been deposited in an elongated, northeast-trending basin on the southeastern Laurentian margin. The fauna developed along this margin, but in contrast to possibly adjacent Irish and Scottish assemblages, was located in much shallower water.

The endolithic mytilid bivalve, Lithophaga palmerae n. sp., from the Upper Eocene Ocala Limestone of north-central Florida, sheds new light on the evolution of lithophagids with its unspecialized morphology and highly specialized mode of life. Lithophaga palmerae n. sp. inhabited dead and living coral as indicated by orientation evidence. In living coral, the anterior end of the borehole was sealed off with thick, continuous, “false floors” of CaCO3, as the posterior end was extended to keep pace with coral growth. To date, this new species of lithophagid has been found associated with only one host coral, Actinastrea cf. A. incrustans (Duncan). Association with living coral is found today in L. bisulcata (d'Orbigny) and L. dixonae Scott from the Caribbean and in several Red Sea and Indo-Pacific lithophagids. In the fossil record, live-coral boring has been reported from the Miocene of the Vienna Basin of Austria and from the Pleistocene of Grand Cayman Island in the Caribbean. Lithophaga palmerae n. sp. provides a valuable ancestral link in the evolution of Lithophaga by extending the range of live-coral boring back to the Eocene of Florida.

A rare new turban-shaped basal Middle Cambrian gogiid eocrinoid, Turbanicystis inflatus new genus and species is described from the Kaili Formation (Kaili Biota), Guizhou Province, China. It co-occurs with three other markedly different gogiids, Sinoeocrinus, Globoeocrinus, and Balangicystis, and is part of a unique Middle Cambrian community that is dominated by echinoderms.

A single specimen of a shrimp-like crustacean, Devonostenopus pennsylvaniensis, new genus and species is described from the Huntley Mountain Formation, which is Devonian–Carboniferous (Mississippian) in age. The specimen was collected in north-central Pennsylvania. Devonostenopus pennsylvaniensis is attributed to Stenopodidae. Co-occurrence of the specimen with pinnules of Archaeopteris halliana Goeppert, 1852, suggests that it is Devonian in age. Occurrence of a stenopodidean in the Devonian of North America is significant, as only three definitive decapods have been previously described from the Paleozoic and only two have been described from the Devonian. The earliest stenopodideans described to date are Cretaceous (Cenomanian and Santonian) in age. As such, Devonostenopus pennsylvaniensis extends the geologic range of Stenopodidea from Cretaceous to Late Devonian. Occurrence of a stenopodidean in the Devonian of North America, as well as the occurrence of the only two other known Devonian decapods in North America, suggests that Laurentia might have been a major area of endemism for Devonian decapods.