The Welton Member of the Scotch Grove Formation at Shaffton Quarry, near Camanche, Iowa, is about 427 Ma old and contains numerous metaconulariid specimens, many of which are preserved in apex-downward orientation. Some of these show an unusual, splayed, “Maltese cross” configuration. Apex-downward configurations suggest rapid burial, consistent with the soft part preservation known in other taxa from this locality. The abundance of Metaconularia at Shaffton Quarry, and of topotype specimens of M. aspersa, the generic type species, permits evaluation of the degree of individual and intracollectional variation in peridermal ornament. Variation within and among individuals precludes reliance on ornamental differences in species differentiation in most cases. In view of these results we assign all Shaffton specimens to Metaconularia manni (Roy, 1935), and revise Metaconularia based on its type material from Europe and other material from Europe and North America. An exploratory phylogenetic analysis highlights aspects of character distribution within the genus, but the small number of characters states and possible taphonomic influences upon them limit confidence in the clade topology. Subgroups within the genus are characterized by larger, discoidal papillae, and by strong transverse corrugation and sinuous rows of smaller papillae. The genus itself comprises those conulariids with an external ornamentation of simple, round, small papillae, paired internal septae along the midlines, and a thin periderm that was to some degree pliable during life.

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 19^th 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.

During the Pliocene, the diversification of the tribes Lamini and Camelini of the Family Camelidae took place in most of North America, but at present in Mexico the systematics of Pliocene Camelidae are poorly known. Fossil material described in this paper was recovered from Blancan I and Blancan III age floodplain and point bar deposits of the San Miguel de Allende basin, Guanajuato state, central Mexico, which approximately spans a time frame from 4.7 to 3.0 Ma. The identified taxa include the lamines Hemiauchenia blancoensis (Meade) 1945, Hemiauchenia gracilis Meachen, 2005, Blancocamelus meadei Dalquest, 1975 and Camelops sp., while the camelines are represented by Megatylopus sp. The records of H. gracilis and B. meadei in the Pliocene of central Mexico are the oldest in North America. Previous studies of the probable feeding strategies of these taxa indicate that they were browsers or browser-like intermediate feeders and just one was an intermediate feeder. The records of these species in the Early Blancan of Guanajuato extend their geographic distribution from the southern USA to central Mexico.

A diverse assemblage of Middle Cambrian sponges, recently collected from the Wheeler and Marjum Formations of western Millard County, Utah, includes a variety of demosponges and hexactinellids. This collection includes the verongiid Vauxia bellula Walcott, 1920, and the protomonaxonids Choia carteri and Choia ridleyi Walcott, 1920, Hamptonia bowerbanki Walcott, 1920, and Hamptonia parva n. sp. Hexactinellids in the collection include the reticulosid protospongioids Diagoniella hindei Walcott, 1920, and Diagoniella magna n. sp.; the dierespongioid hydnodictyid Valospongia? gigantus Rigby, 1973; and the hintzespongioid Hintzespongia bilamina Rigby and Gutschick, 1976. A specimen of the problematic Sentinelia? draco Walcott, 1920, is also documented as part of the collection.

Fossils of the giant short-faced bear, Arctodus simus (Cope, 1879), have been recovered from over 100 localities in North America, extending from Mexico to Alaska and California to Virginia. Despite this large range, the species has never been recorded from the southeastern United States. The lesser short-faced bear, Arctodus pristinus Leidy, 1854 is well represented from this region, particularly Florida, but all known occurrences are late Pliocene – middle Pleistocene in age (about 2.5 to 0.3 Ma). Differentiating A. simus from A. pristinus can be difficult because large individuals of A. pristinus overlap in size with small individuals of A. simus, and there are few morphological differences. However, these two taxa can be clearly separated based on the relative proportions of their molars and premolars. Two Pleistocene records of A. simus representing a minimum of three individuals from the Withlacoochee River drainage of central Florida are reported here, substantially extending the distribution of this massive bear into southeastern North America. A late Pleistocene age for these occurrences is corroborated by an associated Rancholabrean fauna and rare earth elemental analyses. One of the reported individuals is quite large, supporting the hypothesis of extreme sexual dimorphism in A. simus and rejecting a hypothesis of two subspecies.

Ptiloncodus Harris, 1962, a hook-shaped microfossil, is present in late Floian through Hirnantian [ = late Ibexian through Gamachian] rocks in regions marginal to Laurentia. Specimens from the Great Basin provide additional information about this enigmatic microfossil. Two fused clusters of Ptiloncodus elements from western Utah do not duplicate clusters reported previously from coeval strata in central Nevada. EDS spectra confirm the long-standing assumption that these fossils are composed of calcium phosphate. SEM images show that short crystallites are aligned to provide fibrous surficial ultrastructure in the hooked part of these fossils, but more open arrangement is displayed at the top of the shank where paired lobate structures are attached. The join between the lobes and the shank is weak; these two parts of the fossil separate easily so that most specimens did not retain lobes. The shanks end in rounded terminations or in paired knobs that range from low protuberances to near horn-like features. The new data do not support any of several suggestions that compare Ptiloncodus to extant organisms, and uncertainty continues about its affinity and the function of its skeletal elements.

We report here the first crustacean microcoprolites from the Sambosan Accretionary Complex (AC) in Japan. Three species of crustacean (order Decapoda) microcoprolites - Payandea japanica n. sp., Favreina tosaensis n. sp., and a species belonging to the genus Parafavreina? sp. are described from the Late Carnian to Rhaetian shallow-water limestones of the Sambosan AC, which were originated on extinct and subsiding volcanoes forming a mid-oceanic atoll-type buildup in the Panthalassan Ocean. Coprolites, which occur within a lagoonal to back-reef facies, provide new insight into the micropaleontology and sedimentology of the Sambosan limestones. Their presence in this tropical shallow-water depositional setting heightens their status of sedimentary facies indicators of such environments. Furthermore the occurrence of these Tethyan coprolites genera in Japan improves our knowledge of the distribution of Triassic crustacean decapods across the Panthalassan Ocean.

The fluid flow through the complex hydrospires of the spiraculate blastoid Pentremites rusticus was analyzed using the first high-resolution three-dimensional digital image (and animation) of the hydrospires taken from a serially sectioned specimen. Measurements of the cross-sectional areas within the hydrospires, in conjunction with the Principle of Continuity, were used to infer the relative water velocity throughout the structures. Even though the calyx narrows adorally, the hydrospires expand in size, keeping pace with the increasing volume of water that entered through the hydrospire pores. Thus, the water maintained a relatively constant velocity within the hydrospire canals, 3.4 to 4.5 times the incurrent velocity. The spiracular openings are sufficiently large that no substantial increase in the exit velocity of the seawater would have been achieved unless the spiracular cover plates were used to reduce the size of the spiracular openings, which we infer was probably the case. The three-dimensional images underscore the fact that the two hydrospires that lie under each ambulacrum do not share the same spiracle and are not connected. Thus, we here redefine the term “hydrospire set” to refer to the pair of hydrospires that are connected. A number of anomalous accessory pores and canals were identified in the digital images. This initial study is based on a single specimen, and thus we were unable to determine the full range of variation present in Pentremites rusticus. Nonetheless, the digital image and the application of the Principle of Continuity offer new insights into the form and function of these remarkable respiratory structures.

Two species of well-preserved phyllocarid crustaceans, Ceratiocaris macroura n. sp. and Ceratiocaris papilio Salter, occur in the Eramosa Formation Lagerstätte of Ontario, Canada, represented by several dozen articulated fossils preserving limbs and thoracic segmentation. Ceratiocaris macroura n. sp. is distinguished by possession of an exceptionally elongate telson in relation to its body length. Ceratiocaris papilio preserves fine detail of the abdominal scale-like ornamentation, allowing reinterpretation and enhanced characterization of this key feature. Ceratiocaris papilio has a wide paleogeographic distribution across Laurentia but is restricted to shallow marine depositional settings within the middle Silurian.

Cladistic parsimony analysis of the subfamily Deiphoninae Raymond, 1913 was conducted to produce a hypothesis of relationship for the group. The genera Deiphon Barrande, 1850 and Onycopyge Woodward, 1880 are found to be monophyletic, while the genus Sphaerocoryphe Angelin, 1854, as it was previously defined, is paraphyletic. A modified Brooks Parsimony Analysis using the phylogenetic hypothesis reveals patterns of biogeography, in particular, vicariance and geodispersal, during the Ordovician-Silurian. The analysis yields three major conclusions about deiphonine biogeography: Eastern Laurentia and Baltica were close enough during the late Ordovician to exchange taxa via sea level rise and fall; chance dispersal occurred between Northwestern Laurentia and Australia; and deiphonine trilobites likely originated in Baltica or Eastern Laurentia.

Two abdominal molts representing a small cymothoid isopod are described from the marine late Miocene Gram Formation of southern Denmark. Abdominal molts are generally regarded as being difficult or even impossible to assign to genus or family due to overlap of morphological characters. A preliminary study supported by statistical and multivariate analysis of the genera most closely resembling the specimens reveals that although some overlap in characters do occur, the genera can to a large extent be defined by a diagnostic set of features. The Danish Miocene taxon described herein is assigned to AegaLeach, 1815 as the only known fossil of this important cosmopolitan genus.