Forty-seven samples of the Bromide Formation (Simpson Group) of south-central Oklahoma produced a collection of 10,216 conodonts assigned to 46 species. The conodont fauna is dominated by species of Phragmodus and Plectodina and indicates a latest Whiterockian to early Mohawkian (Black Riveran) or late Llandeilian to early Caradocian age. Five new species are named including Ansella crassa, Bryantodina aequalis, Plectodina edentula, Walliserodus declivis, and Pharagmodus ambiguus. The latter species is distinct from Phragmodus flexuosus Moskalenko, a species to which it has been assigned in past reports.

Analysis of conodont distribution with respect to the shallow-water Bromide lithofacies distinguishes shallow to deeper water conodont associations. Samples from shallower water facies contain Ansella crassa n. sp., Cahabagnathus sweeti (Bergström), Curtognathus spp., Eoplacognathus elongatus (Bergström), Erismodus typus Branson and Mehl, Oneotodus? ovatus (Stauffer), Phragmodus ambiguus n. sp., Phragmodus flexuosus, and Staufferella falcata (Stauffer). Samples from deeper water facies contain forms such as Ansella nevadensis (Ethington and Schumacher) and Baltoniodus gerdae (Bergström).

Seemingly consistent proportional differences in several palatal structures have been noted between Permian and Triassic anomodont therapsids for nearly a century. These patterns have been cited as evidence in support of a decline in atmospheric oxygen concentrations that may have contributed to end-Permian terrestrial extinctions. However, it is not known whether the observed differences are significant, or whether they stem from continued directional selection. If they are not significant, or if their timing does not match that proposed for the oxygen decline, support for the hypoxia-based extinction scenario would be weakened. We tested whether the internal nares and bony secondary palate, two palatal features proposed to be related to respiratory efficiency, are significantly larger in Triassic anomodonts, and whether the variation can be attributed to a long-term tendency for increase. Results based on raw data indicate that Triassic anomodonts have significantly larger secondary palates than Permian anomodonts. They also have significantly larger internal nares, but only when primitive, morphologically-divergent specimens are not considered. Although nares and palate size are correlated with stratigraphic occurrence, available data reject the hypothesis that the observed differences were the result of a long-term trend. Most of these findings are consistent with the predictions of the hypoxia scenario. However, removing the effects of body size and phylogeny causes some of the differences to break down, indicating that if selection for increased respiratory efficiency affected these characters, it was most likely not the only factor to do so. Therefore, the characters provide only weak evidence in support of the hypoxia scenario, and we recommend against their use for this purpose. Our results emphasize the need for caution when invoking presumed differences between Permian and Triassic vertebrates as support for hypoxia, or other extinction scenarios, without a rigorous study of the character(s) in question.

Hadrosaur Bones have been found on the Colville River north of Umiat on the North Slope of Alaska. This find represents the first report of dinosaur bones in Alaska and their northernmost reported occurrence. The remains are not determinable below family level but are important, nonetheless, for interpretations of the paleoclimatology and paleobiogeography of the Late Cretaceous.

Feminization of adult male xanthid crabs, Tumidocarcinus giganteus Glaessner, from the Miocene of New Zealand, represents the first notice of the phenomenon in the fossil record. Marked broadening of the abdomen of adult males, to assume a form much like that of mature females and limitation in the size of the major claw likely result from parasitic castration by rhizocephalan, probably kentrogonid, barnacles. A sexually aberrant dakoticancrid, Dakoticancer overanus Rathbun, from the Late Cretaceous of South Dakota (Bishop, 1983) may extend this coevolutionary relationship between parasitic barnacles and decapod crustaceans into the Mesozoic.

Extraordinarily rare phosphatized embryos liberated from fossiliferous limestone of the Middle Cambrian (about 500 Myr old) Gaotai Formation of Duyun, southern China, are assigned to Markuelia qianensis n. sp. Several specimens with increasing numbers of blastomeres may represent four successive cleavage stages, seemingly exhibiting a radial holoblastic cleavage pattern. No subsequent stages showing gastrulation were observed. However, several specimens are late, pre-hatching stages, each with a vermiform shape coiled in either left-or right-handed directions within the fertilization envelope. These specimens indicate that the intuitively assumed difference in preservation potential between early cleavage and late pre-hatching stages is probably not valid. This new material clarifies the affinity of the first fossilized invertebrate embryos ever described, from the same rocks, which were originally attributed to arthropods, presumably trilobites. Instead, they belong to scalidophorans, and this finding infers likely diversified cleavage patterns for stem members of this group, and yields fresh insight into the embryogenesis of early metazoans as a whole.

New records of Late Triassic reptiles from the Chinle Formation of Arizona include a new species of small trilophosaurid, a sphenodontid, and two taxa of eolacertilians. ?Trilophosaurus jacobsi n. sp. is a small trilophosaurid showing affinities to the type of Trilophosaurus buettneri of the southwestern United States and Variodens inopinatus from the Upper Triassic of Great Britain. A sphenodontid is also reported along with maxillae tentatively referred to the Kuehneosauridae and a jaw fragment from a subpleurodont eolacertilian with polycuspate teeth.

The Cambrian fossil record of the Arachnomorpha is rich and diverse and includes trilobites, chelicerates, and many taxa known from various soft-bodied faunas including the Burgess Shale and the Chengjiang. Exceptionally well-preserved arthropod fossils are also known from Middle Cambrian strata in Utah. Recently, two new arachnomorphs (Dicranocaris Briggs, Lieberman, Hendricks, Halgedahl, and Jarrard, 2008 and Nettapezoura Briggs, Lieberman, Hendricks, Halgedahl, and Jarrard, 2008) were described from the Wheeler and Marjum formations of Utah. Cladistic analysis is undertaken to investigate arachnomorph relationships in light of these two new genera. The character matrix of Edgecombe and Ramsköld (1999) serves as the foundation for this study, augmented by new characters and taxa. The results of our cladistic analysis suggest that at least three distinct arachnomorph clades had diverged by the Middle Cambrian, and perhaps much earlier; the Utah genera can be referred to groups within one of these clades.

Echinoderm skeletal debris from the Early-Middle Cambrian boundary Micmacca Breccia of Morocco includes the oldest known holomeric columnals. the original calcite of these ossicles is coated and replaced by iron oxides, occasionally overlain by a late coating of silica, and preserves with high fidelity fine details of their three-dimensional microstructure. Irrespective of their external morphology, columnals can be divided into three groups based on the distribution of stereom microfabrics, which we suggest indicates the presence of at least three different holomeric stemmed taxa. One of these columnal types has well-developed galleried stereom perpendicular to its articulation facets, a sure sign that long, penetrative collagen bundles bound columnals together, as in modern stemmed crinoids. This columnal morphology also shows a primitive type of interlocking articulation, which we term parasymplexy and which may have helped to counter torsional stresses. the two other columnals either lacked fibrous connective tissue or had shallow, non-penetrative fibers between columnals.

Macropodoids from the Tarkarooloo local fauna, including Nambaroo tarrinyeri n. gen. and sp., N. saltavus n. sp., N. novus n. sp. and Palaeopotorous priscus n. gen. and sp., include the most plesiomorphic macropodids and potoroids known. Together with the newly discovered macropodoids from the Pinpa and Yanda local faunas they are also the oldest macropodoids described. Study of the morphology of these plesiomorphic macropodoids indicates that the trigonid of the M2 in potoroids and macropodids is composed of different structures (the protoconid and metaconid in macropodids and the protoconid and protostylid in potoroids). Also, the posterior cingulum in macropodids is a neomorphic structure, and not homologous with the posterior cingulum (the posthypocristid and postentocristid) in potoroids and phalangerids. A unique M2 trigonid configuration, where the cristid obliqua connects with the protostylid, is here recognized as being present in plesiomorphic macropodoids and phalangerids, and possibly represents a synapomorphy for a clade containing members of those groups.

Three new and one completely preserved species of hexactinellid sponges are described from Early Cambrian black shales of South Anhui, China. The sponges occur in the middle part of the Huangboling Formation, which is assigned to the early Canglangpuian based on trilobite biostratigraphy. Metaxyspongia skelidata n. gen. and sp. and Hexatractiella dongzhiensis n. sp. are subcylindrical thin-walled Protospongiidae. Ratcliffespongia multiforamina n. sp. is assigned to the Hintzespongiidae. With these new sponges, the first occurrences of the Protospongiidae and Hintzespongiidae, and of Hexatractiella Mehl, 1996, can be traced back to the Early Cambrian. Solactiniella cf. plumata Steiner et al., 1993, with irregular rossellimorph skeletal architecture and regular spicular organization, is found here associated with the above species. Thus, the Anhui assemblage can be considered as intermediate between Atdabanian shallow-water communities of hexactinellids with irregular skeletons and the Middle Cambrian deepwater sponge facies characterized by regularly organized Hexactinellida.

Radiolaria extracted from two bedded-limestone and two limestone-concretion samples from the upper Llandovery of the Cape Phillips Formation, Cornwallis Island, allow the distinction between the spicular haplentactinid subfamily Secuicollactinae and the nonspicular Rotasphaeridae. This restores Secuicollactinae and returns Secuicollacta to the subfamily from the Rotasphaeridae. Secuicollactinae represent 36 percent of the fauna and are assigned to three genera, Secuicollacta, Diparvapila new genus, and Parvalanapila new genus; these form 27, five, and three percent of the fauna, respectively. The remaining one percent of the subfamily is unassigned. Rotasphaeridae form four percent of the fauna and are represented by Rotasphaera. Secuicollacta is diagnosed on the basis of the presence of an ectopic spicule in addition to several rotasphaeridlike primary units. The salient characters of Diparvapila include two lattice shells with an ectopic spicule on the medullary shell. Parvalanapila is diagnosed on the basis of a lattice sphere overlain by a labyrinthine layer and an ectopic spicule on the lattice sphere. New species described here are Secuicollacta malevola, S. sceptri, S. gliris, S. herrimani, S. segari, S. vallipuellae, S. resodiosae, S. glaebosa, S. teli, Diparvapila hicocki, D. saintrochae, D. larseni, Parvalanapila fleischerorum, and Rotasphaera severa. Four species of Secuicollacta are reported in open nomenclature, as are two of Diparvapila and two of Rotasphaera.

Radiodontan body elements, some belonging to Peytoia and Hurdia and some unassigned, have been reported from the Langston Formation (Spence Shale Member), Wheeler Formation, and Marjum Formation of the middle Cambrian (Series 3) of Utah. These identifications are reassessed in light of recent work on the morphology of the radiodontan Hurdia. New specimens of Hurdia are identified from the Spence Shale, representing mouthparts (oral cones), cephalic carapace H-elements, frontal appendages, and a single isolated swimming flap. The shape of the H-elements allows H. victoria Walcott, 1912 to be identified from the Spence Shale for the first time. The flap is larger and more complete than any reported from the Burgess Shale and allows for a better understanding of the morphology of Hurdia swimming flaps. A 3D model of a Hurdia frontal appendage indicates that there is only one morph of Hurdia frontal appendage found in both species, and apparent morphological differences between disarticulated appendages reflect a preservational continuum caused by varying oblique angles relative to the seafloor. Peytoia should no longer be reported from the Spence Shale, but its presence is confirmed in the Wheeler and Marjum formations. New mouthparts (oral cones) of Hurdia from the Spence Shale and Peytoia from the Marjum Formation with surface textures of submillimeter-diameter raised nodes are described. These new features have not been observed in material from the Burgess Shale and suggest slight differences in preservation.

Numerous specimens of Tabulaconus Handfield, 1969, have been collected in carbonate buildups within the Adams Argillite (Early Cambrian, Tatonduk area, Alaska). The wall structure of this form has been investigated, along with contemporaneous archaeocyaths and algae, through the use of polished ultra-thin sections (2–3 μm thick) and scanning electron microscopy. The results of this microstructural comparison indicate that despite diagenetic alteration Tabulaconus has a skeleton that is unlike any presently known and is quite distinct from associated algae or archaeocyaths. It is more elaborate than that found in the archaeocyaths but has not reached the stage of complexity seen in the primitive coral Cothonion Jell and Jell, 1976. The presence of some elongated units may represent an initial step towards the fibrous skeleton typical of Paleozoic corals.

This study shows that even though diagenesis alters the original microstructure of calcareous skeletons, the resultant fabrics and detailed structures can be useful in systematic descriptions.

Tabulaconus is removed from the Gastroconidae Kordae due to the presence of rudimentary septa and constitution of the tabularium. A number of species assigned to the genus Bačatocyathus Vologdin and included within the Archaeocyatha appear to be examples of Tabulaconus or very close relatives. An emended description of Tabulaconus kordae, the type species, is proposed.

Late Givetian and early Frasnian conodont communities with Icriodus subterminus have been revised on the basis of collections from Iowa (USA), the Boulonnais and the Ardennes (northern France and Belgium), the Radom-Lublin area and Holy Cross Mountains (Poland), and the Ma'der-Tafilalt region (southeast Morocco). As a result an Icriodus subterminus Zone with a threefold subdivision is defined. The three subzones correspond approximately to the “Lower and Upper subterminus Fauna” and the “insita Fauna” commonly used in N America for the study of shallow-water platform carbonate successions.

The base of the subterminus Zone corresponds to a level within the uppermost part of the hermanni Zone; the top is characterized by the occurrence of the earliest Ancyrodella taxa, Montagne Noire Zones MN 1 and the base of MN 2 or slightly above the base of the falsiovalis Zone.

The diagnosis of Icriodus subterminus is amended and two morphotypes are recognized. The stratigraphic range of the alpha morphotype is confined to an interval between the uppermost part of the hermanni Zone and the top of the MN 3 Zone; the beta morphotype may range into the MN 6 Zone.

The holotype of Icriodus subterminus from the North Liberty beds in Iowa is most likely a specimen that was reworked from the Cedar Valley Limestone. Icriodus cedarensis and Icriodus tafilaltensis are described as new species, and the diagnoses of Icriodus excavatus and Icriodus expansus are amended. Between the Icriodus difficilis and Icriodus symmetricus zones, an Icriodus expansus Zone is defined.

Trace fossils are used in deposystem analysis of Late Devonian–Early Mississippian nearshore facies in the north-central Appalachian Basin. These nearshore facies resulted from separate transgressions during latest Devonian (Cleveland Shale) and earliest Mississippian (Sunbury Shale) time. Emphasis is placed on a well-exposed section at Rowlesburg, West Virginia, where the Oswayo, Cussewago Sandstone, and Riddlesburg Shale Members of the Price Formation are exposed.

The Oswayo Member at Rowlesburg preserves an offshore-to-lower shoreface transition in a complex of euryhaline, protected-bay, lagoon, and possible estuarine facies. Cruziana is common and occurs along with Arthrophycus, Bifungites, Chondrites, Planolites, Palaeophycus, Rhizocorallium, Rosselia, Rusophycus, and Skolithos in intensely bioturbated mudstone, siltstone, and sandstone. These lithologies were deposited below fair-weather wave base and grade upsection to upper shoreface facies comprised of thick, horizontally-laminated sandstones with thinner, burrowed mudstone interbeds. Upper shoreface traces consist of Arenicolites, Cruziana, Diplocraterion, Dimorphichnus, Planolites, Thalassinoides, and Skolithos. Skolithos “pipe rock” sandstones occur at the toe of upper shoreface facies. Eastward the Oswayo Member grades into a restricted-bay facies and finally into beach and tidal flat facies near its stratigraphic wedge-out in eastern West Virginia and western Maryland. The Cussewago Sandstone Member at Rowlesburg overlies the Oswayo and is bounded at the top by a disconformity. The Cussewago contains Arenicolites, Isopodichnus, Phycodes, Planolites, and Skolithos in upper shoreface sandstones possibly related to deposition in deltaic or tidal channel systems.

Regionally, the Riddlesburg Shale records a range of euryhaline environments in shallow-shelf, open-bay, and probable estuarine facies. The Riddlesburg Shale Member at Rowlesburg is comprised of dark-grey silty shales, siltstones, and hummocky cross-stratified sandstones. Trace fossils include Bergaueria, Bifungites, Fustiglyphus?, Helminthopsis, Planolites, and Skolithos. Lithofacies of the Riddlesburg Shale in West Virginia were markedly influenced by a syndepositionally active basement feature, the West Virginia Dome. Riddlesburg-age shoreface sandstones deposited on the crest of the Dome contain apparent omission surfaces with common Rhizocorallium and Arenicolites, Cruziana?, Planolites, and Skolithos.

Strata in the Central Alborz Mountains, northern Iran, are interpreted to show continuous sedimentation from Ediacaran through Cambrian times. The Soltanieh Formation consists of five members: Lower Dolomite, Lower Shale, Middle Dolomite, Upper Shale and Upper Dolomite members. The clastic units (Lower and Upper Shale members) represent sedimentation in distal marine settings, ranging from the shelf to offshore, and contain abundant trace fossils of biostratigraphic utility. Four ichnozones have been recognized. Ichnozone 1, containing Helminthoidichnites tenuis, Helminthopsis tenuis, and Cochlichnus anguineus, is early Fortunian based on small shelly fossils, and is interpreted as a distal expression of the Treptichnus pedum zone. Ichnozone 2, comprising the first occurrence of T. pedum, is middle Fortunian, and is best regarded as the upper half of the Treptichnus pedum Zone. Ichnozone 3 is late Fortunian–Cambrian Age 2, characterized by a sudden change in abundance and complexity of trace fossils. Main elements in this ichnozone include Cruziana problematica, Curvolithus isp., Phycodes isp., Treptichnus pedum, Treptichnus pollardi, and Treptichnus isp. Ichnozone 4 is of Cambrian Age 2–Age 3 and marked by the first appearances of Psammichnites gigas, Rusophycus avalonensis, and Didymaulichnus miettensis. Integration of trace fossils with small shelly fossils suggests that the Ediacaran–Cambrian boundary should be placed at the base of the Soltanieh Formation or within the Lower Dolomite Member. The delayed appearance of T. pedum and the low ichnodiversity in the Lower Shale and lower interval of the Upper Shale reflect limited colonization of settings below storm wave base during the early Fortunian.

Lobopodians, which diversified and flourished in the Cambrian seas, have long drawn much attention in that not only their extant close relatives, onychophorans and tardigrades, but euarthropods (Chelicerata, Myriapoda, Crustacea, and Hexapoda) may have been deeply rooted in stem-group lobopodians. Antennacanthopodia gracilis new genus and species is described and interpreted here as an “unarmoured” lobopodian from the Chengjiang fossil Lagerstätte (Early Cambrian, —520 Ma), Yunnan, southwestern China. This animal shares with other known Cambrian lobopodians such plesiomorphies (primitive characters) as onychophoran-like overall appearance; a metamerically segmented body covered by slightly sclerotized cuticle, and paired, unjointed lobopodal legs. Antennacanthopodia is also featured by a pair of frontal antennae, potential ocellus-like lateral visual organs, second antennae, a straight, voluminous midgut, diminutive spines arrayed on the leg and the trunk, well-developed leg musculature, highly sclerotized terminal leg pads, and presumptively a pair of posteriormost appendicules. This new taxon, with innovative characters (autapomorphies), furthers our understanding of early lobopodian diversification. Antennacanthopodia is considered closely allied to extant Onychophora based on considerable anatomical similarities. Taken together its “two-segmented” cephalization and appendage-bearing “ocular segment”, this new form may shed some new light on the arthropod groundplan.

Upper Pennsylvanian dysoxic marine shales of midcontinent North America yield permineralized remains of apparently extrabasinal vegetation. A large percentage of the plants are surprisingly unlike the well known swamp, fluvial and lacustrian floras of the late Paleozoic paleotropics, revealing numerous aspects of the morphology, anatomy and reproductive biology of plants that may have been ancestral to the dominant taxa of the Mesozoic. Included among the assemblages are ovulate coniferophyte remains that demonstrate the occurrence of vojnovskyalean seed plants in equatorial Euramerica. Specimens consist of simple ovulate cones that are more-or-less clustered along eustelic stems in the axils of helically arranged, strap-shaped leaf bases, and are described as Sergeia neuburgii new genus and species. Individual cones are up to approximately 2 cm long and 1.5 cm in maximum diameter, with helically arranged scales and sporophylls that diverge from a eustelic axis. Scales occur in the basal region of the cone, and are laminar and pointed. Sporophylls are borne distally. One specimen shows about 45 sporophylls, each of which terminates as one erect ovule. Most of the other cones have abraded apices, and terminate in relatively terete foliar appendages that are interpreted to be sporophyll bases. Ovules are flattened and winged, approaching 180° rotational symmetry. Integument histology, vascular tissue distribution and pollen chamber structure are similar to those of cordaiteans and callistophytalean seed ferns. Sergeia adds to the number of late Paleozoic conifer-like plants that do not conform to the Pinopsida as traditionally circumscribed, and poses additional questions to assumptions of monophyly for coniferophytes and for conifers sensu lato.

A new basal basilosaurid cetacean, Basilotritus uheni n. gen. n. sp., comes from the late middle Eocene (Bartonian) of Ukraine. It is the earliest dated record of a cetacean from Eastern Europe. The tympanic bulla of Basilotritus uheni shares basilosaurid synapomorphies but possesses unusual traits inherited from protocetids. Cetaceans related to Basilotritus uheni and referred to as Eocetus or “Eocetus” have been recorded from Africa, Europe, North America and South America. “Eocetus” wardii from North America is recombined as Basilotritus wardii. Platyosphys paulsonii and Platyosphys einori from Ukraine are considered as nomina dubia; specimens prior referred to as Platyosphys sp. are similar or related to Basilotritus. Other records of the Eocene cetaceans from Ukraine and south Russia are identified as Basilotritus or related genera. Early basilosaurids are demonstrated to be a paraphyletic, morphologically and geographically diverse group of the genera that colonized the world ocean as late as in Bartonian age and were probably the ancestors of Neoceti, as well as of more derived basilosaurids.

Two species of the heteromorph ammonite genus Diplomoceras Hyatt are described from the Upper Cretaceous of the James Ross–Seymour Islands area, Antarctica. The late Campanian–early Maastrichtian D. lambi Spath has a relatively high rib density, whereas D. maximum n. sp. has a lower rib density and is known only from the uppermost Maastrichtian of the Lopez de Bertodano Formation on Seymour Island. Both species attain an exceptionally large size with the body chamber of D. maximum n. sp. attaining a length in excess of one meter. The structure of the shell wall in Diplomoceras is characterized by the thickening of the nacreous layer below the ribs. The shell thickening results in an inner flat surface and a smooth phragmocone. Reconstruction of the shell suggests at least four parallel shafts and three U-connectives. Estimates of the total density, center of buoyancy, and center of mass in this reconstructed shell indicate a slightly positive buoyant shell with a relatively unstable floating position.