“Complete” crinoids are rare fossils in the lower Paleozoic of Ireland. Cryptanisocrinus kilbridensis n. gen. and sp., from the Upper Llandovery (Telychian) Finny School Beds of the upper Kilbride Formation, County Mayo, is an anisocrinine homalocrinid and the first Irish lower Paleozoic flexible crinoid. The unique holotype is an external mold without counterpart that does not retain the anal series. Cryptanisocrinus kilbridensis has a kylixiform dorsal cup, a low but prominent, infrabasal circlet, low, triangular basals, arms that branch isotomously at least three times, and two interprimibrachial plates in each interray, the lower of which is the larger.

The importance of hydrodynamic lift to the autecology of stalked crinoids was evaluated by comparing the maximum hydrodynamic lift experienced by the crinoid crown to the weight of the crinoid in water. Results of the analysis suggest that even under optimum conditions a current velocity of over 20 cm/s would be required to produce enough lift to overcome the animals' weight in water. This implies that under normal conditions crinoids could not function as kites, using the stalk as a tether, unless they possessed some means of reducing their densities. Lift, however, may play a role in the reorientation of crinoids in response to current direction changes, and also in elevating the crown above the substrate following dislodgement or crawling.

Contrary to ideas that Cretaceous fresh waters contained few teleosts, there were several taxa of Esocoidei (pikes and relatives) in North American Cretaceous rivers. Dentaries and palatines of Campanian to Maastrichtian age all have C-shaped tooth bases and other distinctive features of shape and foramina. The fossils include at least three distinct kinds, two of which are described here as new genera and species in the Esocidae: Estesesox foxi n. gen. and sp. and Oldmanesox canadensis n. gen. and sp.

These old, diverse, and apparently primitive specimens show that pikes radiated when Eurasia and North America were still joined. Some references in the literature to the Cretaceous fish Platacodon Marsh are based on referred dentaries that are here identified as esocoid fossils. The Esocidae are the first example of a family of Recent North American freshwater teleosts that has been shown to have speciated in Cretaceous fresh waters and survived the terminal Cretaceous extinction.

New specimens of aglaspidid arthropods, mainly from the Upper Cambrian St. Lawrence Formation of Wisconsin (Upper Dikelocephalus Zone), show that appendages previously assigned to the genotype Aglaspis barrandei actually belong to a new genus and species Flobertia kochi. Chraspedops fragilis is transferred to a new genus Tuboculops. The generic attribution of Aglaspis dorsetensis and Aglaspis franconensis is queried. The distinction at species level is queried for Setaspis spinulosus and S. regularis and also for Aglaspoides sculptilis and A. semicircularis, although no formal changes are recommended. Aglaspis simplex is transferred to Glypharthrus simplex and Glypharthrus deadwoodensis is synonymized with Glypharthrus vulpes. Restorations are presented of Aglaspis barrandei, Aglaspis spinifer, and Glypharthrus thomasi. Aglaspis spinifer probably had a total of four head appendages. Well-preserved aglaspidid specimens often evince tergal processes that are apparently unique to this taxon and these may have acted as apodemes.

Two cupulocrinids, Cupulocrinus crossmani n. sp. and Praecupulocrinus conjugans (Billings) n. gen., are known from the Middle Ordovician (Galena Group, Dunleith Formation) of northern Iowa and southern Minnesota. Various morphologic and ontogenetic features demonstrate that Praecupulocrinus is more primitive than Cupulocrinus. The two species commonly occur together. In addition, both taxa coexisted at similar levels with stem lengths ranging from about 1.5 cm in juveniles to 15 cm in adults. Relatively complete growth sequences illustrate growth and variation and show how two related crinoids subdivided feeding niches. The crown volume provides a satisfactory surrogate variable for the size of the animal. The food-gathering system of the cupulocrinids is mainly augmented by the addition of new plates at the ends of the arms. The number of plates in the arms and the arm length exhibit positive allometry relative to crown volume, largely due to development of new branches at the arm tips. The food-gathering capacity equals the number of food-catching tube-feet multiplied by the average width of the food grooves. Food-gathering capacity is also positively allometric with respect to crown volume and the amount of tissue that must be supplied with food. Consequently, the ratio of food-gathering capacity:crown volume is either constant or declines slightly with increasing size and age. The food groove width increases throughout ontogeny so adult crinoids ate larger food particles than juveniles. Praecupulocrinus conjugans (Billings) n. gen. has more narrow food grooves than Cupulocrinus crossmani n. sp. of comparable size and age, which suggests niche differentiation based on food-particle size. The arm and tube-foot geometry indicates that both cupulocrinids utilized the same type of suspension feeding.

The morphology of the anal sac and the lack of “patelloid” processes in the arms indicate that Cupulocrinus sepulchrum Ramsbottom from the Upper Ordovician of Scotland belongs to Dendrocrinus.

Alcidedorbignya inopinata Muizon and Marshall is a primitive pantodont from the Early Paleocene of Tiupampa, Department of Cochabamba, in the “Cordillera Oriental” of south-central Bolivia. It is known by almost complete upper and lower dentitions, which are described in detail. The occurrence of abundant juvenile specimens allows a study of tooth replacement. The molars of Alcidedorbignya inopinata are primitive for a pantodont but they show the characteristic synapomorphy of the group, which is the presence of a V-shaped ectoloph of P3-4. However, the paracone and the metacone of A. inopinata are separated at their bases, a feature absent in the Bemalambdidae and Harpyodus, which have connate to semi-connate paracone and metacone. Because of this character, A. inopinata, although the oldest, is not the most primitive pantodont. However, A. inopinata, as in bemalambdids and Harpyodus, does not have a mesostyle on M1-2/ or a strongly V-shaped centrocrista, which are found in all other pantodonts. For this reason, Alcidedorbignya inopinata is removed from the Pantolambdidae (which are too specialized) and referred to the new monotypic family Alcidedorbignyidae. The family Wangliidae Van Valen, 1988, is not accepted here and the genus Wanglia is regarded as a junior synonym of Harpyodus; the latter includes the two species H. euros and H. decorus. Analysis of pantodont origins leads to the conclusion that didelphodontines constitute the best potential sister-group; however, no synapomorphy could be found to substantiate this hypothesis. Alcidedorbignya inopinata is the first pantodont known from a southern continent and, being the oldest, it raises a discussion on the paleobiogeographic history of the group.

Trilobites occur in two generically distinct faunas in the Permian strata of West Texas. The stratigraphically lower fauna, composed of Ditomopyge decurtata (Gheyselinck), Ditomopyge sp., Triproetus angustus n. sp., Triproetus tumidus n. sp., Triproetus altasulcus n. sp., is present in Wolfcampian and early Leonardian strata. The stratigraphically upper fauna, present in late Leonardian and Guadalupian strata, is comprised of Delaria antiqua (Girty), Delaria granti n. sp., Delaria brevis n. sp., Delaria westexensis n. sp., Delaria chinatiensis n. sp., Novoameura vitrumons n. sp., Anisopyge perannulata (Shumard), and Anisopyge cooperi n. sp.

The lower fauna originated in the late Pennsylvanian, inhabited shallow-water environments, was relatively pandemic, and is interpreted to have become extinct as a result of marine regression during the early to middle Leonardian. The endemic upper fauna originated in deep waters of the Marfa and Delaware Basins during the late Leonardian, and, concurrent with sea level rise, migrated and diversified into the shelf-margin reefs of the late Leonardian and Guadalupian. Regression during the Late Permian resulted in extinction of this second Permian trilobite fauna.

The Duchesnean Lac Pelletier Lower Fauna, Cypress Hills Formation, Saskatchewan, includes 15 isolated teeth that are referred to the Carnivora (Mammalia). The fauna includes Miocyon magnus n. sp., Daphoenus cf. D. demilo, Hesperocyon sp., and indeterminate taxa; no members of the Creodonta were identified. This is the latest record of Miocyon and the earliest record of Hesperocyon. The fauna is transitional between Uintan carnivoran faunas that were dominated by miacids and the establishment in the early Chadronian of the White River carnivoran chronofauna, and suggests that the transition, which was largely a Duchesnean event, was gradual.

Aspects of functional morphology are examined and lifestyles proposed for seven exceptionally well-preserved crinoids from the Middle Ordovician Lebanon Limestone, Middle Tennessee. Potential ranges of motion are based on plate shapes, articular surfaces of attachment, and feeding structures. This diverse group of crinoids includes disparid inadunates (Columbicrinus crassus and Tryssocrinus endotomitus), a hybocrinid (Hybocrinus bilateralis), reteocrinids (Reteocrinus polki and R. variabilicaulis), and rhodocrinitid camerates (Archaeocrinus snyderi and Gustabilicrinus plektanikaulos). Using attachment structures as the basis, these crinoids can be divided into two groups: encrusters and commensals. Encrusters are the most diverse and include all taxa except the rhodocrinitids. They have a small discoidal holdfast and xenomorphic column. Proxistele-mesisteles were holomeric or pentameric. Flexure potential of this region of the column in disparids was increased by wider ligament gaps at nodal-internodal articulations; in other taxa flexure was enhanced by increasing the frequency of columnals. Short dististeles are polymeric or a plate mosaic. This region functioned as a resilient buffer between the mesistele and holdfast. Columns as a whole had moderate flexure potential. Feeding-structure design was varied, although all but Hybocrinus bilateralis had pinnulate or nonpinnulate parabolic filtration fans. Hybocrinus bilateralis had atomous arms arrayed in a bilaterally symmetrical pattern; the symmetry plane was oriented parallel to prevailing currents. Commensals in the Lebanon are the rhodocrinitids. Their attachment structures are characterized by a long distally tapering column terminating in a coil. Densely pinnulate arms formed a well-developed parabolic filtration fan.

Encrusters were limited to hardgrounds or skeletal substrata. Commensals were more opportunistic, utilizing a variety of substrates, and they were widespread in Lebanon subenvironments including those with both soft and hard seafloors. Lebanon hardground assemblages are characterized by high diversity, particularly among crinoids and bryozoans. They are strikingly tiered according to elevation above the seafloor (and probably additionally by feeding limitations). This assemblage was the result of longterm coevolution in association with hardgrounds.

Ontogenetic development of the column of encrusting crinoids indicates that the evolution of holomeric columnals occurred through a simpler sequence than previously proposed and need not have included gradual alignment of offset pentameres as intermediate steps. Columnals evolved from a poorly organized plate mosaic through a polymeric stage.

Acid etching combined with scanning electron microscopy (S.E.M.) accentuates a variety of conodont microstructural patterns as compared to unetched specimens. External and internal organic layers surrounding apatitic lamellae are found with internal organic layers apparently thinner than their external counterparts. This may imply partial removal of the outermost organic layer prior to secretion of the next lamella. Etching also provides evidence of internally preserved striate ornament. Polygonal etch artifacts and zones of crystallites aligned in small areas are interpreted as possible sites for apatite biomineralization.

The unusual extant crinoid Holopus rangii d'Orbigny lacks a column, cements directly to hard substrates, has a conical to tubular dorsal cup in which plate sutures cannot be discerned, and has 10 tapered arms that are able to enroll swiftly into a “fist-like” configuration when disturbed. The first SEM study of H. rangii is presented herein. The gross morphology and skeletal microstructure of this species display many characteristics that bear an obvious relationship to the functional morphology of the living animal. Dorsal cups show a range of morphologies, reminiscent of those found in acorn barnacles and other tubular encrusters. During arm enrollment, the adjacent arms abut and form an impervious seal. Of the two specimens dissected, one had a regenerating arm.

The discovery of a specimen of Rhaeboceras coloradoense Cobban, 1987, in the Baculites eliasi zone in east-central Montana is significant for three reasons: 1) it is the most geologically recent occurrence of Rhaeboceras; 2) it connects more closely than previous specimens the lineage between the genus Rhaeboceras Meek and Ponteixites Warren, its apparent smaller descendant; and 3) it significantly extends the geographical range of the species.

Conodont faunas from the upper part of the Wadleigh Limestone, Alexander terrane, southeastern Alaska, are of Frasnian to early Famennian age and include the new taxa Polygnathus aspelundi nanus n. subsp., Polygnathus decorosus dutroi n. subsp., Polygnathus elegantulus sparus n. subsp., Polygnathus gracilis n. subsp. A, Polygnathus n. sp. A, Palmatolepis subrecta youngquisti n. subsp., and Icriodus subterminus uyenoi n. subsp. Four distinct age-determined faunal assemblages are recognized. The lowest is assigned to the Lower Palmatolepis rhenana Zone (the chronozones of Ziegler and Sandberg, 1990, are treated herein as time-rock equivalent assemblage zones). The next is exposed on three small islands just south of Wadleigh Island and is correlated with part of the Lower to Upper Palmatolepis rhenana Zones. The third assemblage, on the eastern side of Wadleigh Island from close to the top of the section, is correlated with part of the Palmatolepis linguiformis Zone. Nearby and overlying this is the fourth assemblage, which is correlated with part of the Lower Palmatolepis triangularis Zone and thus appears to be within the lower Famennian. These Wadleigh Limestone conodont faunas have affinities with faunas from equivalent horizons of the cratonic regions of the Northwest Territories and Alberta in Western Canada and to other faunas globally. The more provincial conodont taxa lend weak but positive support to brachiopod faunal evidence that places the Alexander terrane close to the North American craton during the Late Devonian.

“Phylloid algae” (Pray and Wray, 1963, p. 209) are problematical fossils that occur profusely in Pennsylvanian carbonate microfacies in the United States (Wray, 1968) and many other parts of the world (Mamet, 1991). Taxonomic affinities of most phylloid alga are uncertain. The questionable affinities of phylloid algae and related paleoecologic problems have been summarized by Riding (1977), Wray (1979), and James et al. (1988) and will not, therefore, be repeated here. Our ability to establish probable taxonomic affinities of fossil calcareous algae is dependent largely upon the recognition of their internal microstructures. Because phylloid algae are very susceptible to dissolution and neomorphism, their original internal microstructures are rarely well preserved.

Six extant and nine fossil species of the raninid Lyreidus de Haan, including Lyreidus (Lyreidus) lebuensis n. sp. and Lyreidus (Lysirude) hookeri n. sp., are recognized. Based on morphology of the anterolateral margin and sternum, the species are referred to two subgenera, Lyreidus (Lyreidus) and Lyreidus (Lysirude). The genus first appears in shallow-water, high-latitude, southern hemisphere localities in New Zealand, Antarctica, and Chile in the early Eocene. Subsequently, the nominate subgenus is confined to the southern hemisphere until the Neogene when it dispersed into the Indo-West Pacific region. Lyreidus (Lysirude) is documented by early and middle Eocene occurrences in Antarctica and New Zealand; however, all subsequent occurrences, fossil and recent, are in the northern hemisphere. The disjunct modern distribution within the genus is confined to this subfamily; species are known from the western North Atlantic and the Indo-West Pacific.

A sequence of unusual vertical tubes, arranged in multiple groups, and each tube several meters high occurs in the Middlesboro Member of the Lee Formation (Lower Pennsylvanian). These structures are controversial with various interpretations suggesting either plant or animal origin. Observations supporting a plant origin include: 1) numerous C- and D-shaped, and multichambered tube cross sections are similar to fern and seed fern structures, 2) numerous membrane relicts loosely enclosing the tubes are similar to fern and seed fern tissues, 3) microscopic bundles are observed in cross-sectional thin sections, 4) presence of carbonaceous material and reported fecal pellets over a vertical distance in excess of 5 m are consistent with deteriorating plant material, not escape structures, 5) tubes are composed of casts and molds, but lack spreite or other features typical of escape structures, 6) tubes occur in clusters about one meter in diameter and are associated with coaly material at their base, which suggests that the clusters represent trees, 7) other trace fossils are absent in the enclosing sandstone, 8) tubes branch upward, which is a common structure in plants but unlikely in escape structures, 9) a coalified root structure was found at the base of the sandstone, and 10) all the tubes extend from the bottom of the sandstone to the top. The probability of burrowing animals escaping through as much as 8 m of sand with 100 percent survivorship is low.

The structures may represent a stand of pteridosperms with each “tree” approximately 1–1.5 m in diameter. The individual pipe-organ structures represent aerial stems, shoots, and adventitious roots; each cluster of pipe-organ structures represents a single tree.

Based upon sedimentologic features such as presence of 1) channel form, 2) scoured base, and 3) fining-upward sequence, we interpret the sandstone containing the pipe-organ structures to have been deposited in a sandy fluvial or tidal channel. The unidirectional cross-bed dips, poor sorting, occurrence only of very restrictive fauna and terrestrial flora, position of the sandstone above a possible floodplain facies, and lack of characteristic tidal structures suggest that the sandstone is more probably a sandy fluvial channel that may have minor tidal influence.

Membranous phylloid algae of the late Paleozoic have commonly been identified as Anchicodium Johnson, whereas the genus was originally described as being cylindrical and branched, much like modern Codium. The holotypes cannot be located, but examination of one lectotype specimen and neotypic thin sections from material from several of Johnson's original collection sites indicates that the original descriptions were valid.

The Woodford Shale of south-central Oklahoma was deposited in an offshore, quiet-water, oxygen-poor setting on the southern margin of North America in assocation with other dark organic-rich shales of the Upper Devonian–Lower Carboniferous black-shale facies. The basal Woodford was deposited unconformably over lower Paleozoic carbonate strata as a south-to-north transgressive unit during the Frasnian and early Famennian. Black shales and cherts lie directly above the basal beds.

Phosphatic shales in the upper Woodford contain a conodont succession characterized by three distinct environmentally controlled faunas. The lower fauna is characterized by Palmatolepis gracilis ssp., Branmehla inornata, Bispathodus stabilis, and Pseudopolygnathus marburgensis trigonicus, indicative of the Late Devonian Lower expansa Zone to Upper praesulcata Zone. The middle fauna, which spans the Devonian–Carboniferous (D/C) boundary, is characterized by Polygnathus communis communis and species of Protognathodus. On the Lawrence uplift the D/C boundary is disconformable, as indicated by the absence of Protognathodus kockeli before the first occurrence of Siphonodella sulcata. Light-colored phosphate laminae and beds, indicative of erosion and nondeposition, and a change in biofacies from an offshore palmatolepid–bispathodid fauna to a more nearshore, palmatolepid–polygnathid–protognathodid fauna indicate higher energy conditions and a lowering of sea level associated with the boundary interval. In the eastern Arbuckle Mountains the D/C boundary is apparently conformable, marked by a green shale interval containing a Protognathodus fauna. Species of Siphonodella, indicative of an offshore setting, characterize the third and youngest fauna. The Early Carboniferous sulcata, Lower duplicata, and Upper duplicata Zones are recognized in the upper Woodford. The Woodford Shale is conformably overlain by the “pre-Welden Shale’ and its equivalents, or unconformably overlain by the lower Caney Shale (Osagean?–Meramecian) in the northern outcrop regions and the Sycamore Formation (late Osagean?–Meramecian) in the southern Arbuckle Mountains.

Nine species of fossil isopods have been studied from Cretaceous to Pleistocene rocks of North America. This represents all known species from the Mesozoic and Cenozoic fossil record on this continent. Four species of Palaega were studied. Palaega goedertorum Wieder and Feldmann, 1989, from upper Eocene to lower Miocene rocks of Washington state, has served recently as the basis for restructuring the genus. Emendations are made to species descriptions of Palaega guadalupensis and P. williamsonensis from the Cretaceous rocks of Texas. The fourth species of Palaega, P. lamnae, also from the Cretaceous rocks of Texas, although of doubtful affinities with this genus, was not removed due to lack of sufficient information to reassign it. Two new species are described, Cirolana enigma, from Lower Cretaceous rocks of South Dakota, and Archaeoniscus texanus, from the Cretaceous of Texas. This is the first report of Cirolana from the fossil record. Two sphaeromatid isopods were included: one, Sphaeroma burkartii from Tertiary rocks of Mexico, was not located for study; the other, Eocopea oculata, is from Miocene rocks of southern California. Two specimens of the valviferan genus Saduria, from Pleistocene deposits in Canada, were also studied.