A new species of sturgeon (Acipenseridae), †Psammorhynchus longipinnis n. gen. and sp., is described based on a single well-preserved specimen from the Upper Cretaceous Judith River Formation of Montana. Although based on only a single individual, the osteological detail we are able to describe for this species is extensive because of the completeness of the specimen, the relatively three-dimensional preservation, and the soft, loosely consolidated sandstone matrix in which it was contained (allowing some dissection of the specimen to reveal the internal bones of the head region). We prepared the specimen completely out of the matrix, and described the head region in stages of “dissection.” †Psammorhynchus longipinnis is the only fossil sturgeon to date that provides a relatively complete, reliable look at its osteology. Although there have previously been numerous and widespread reports of fossil sturgeons, the material is notoriously fragmentary and poorly preserved, consisting mostly of isolated scutes or pectoral spines (summarized here in an appendix) and it is of very limited use to phylogenetic studies of living sturgeon taxa. The only other described articulated skeleton of a fossil sturgeon is †Protoscaphirhynchus squamosus Wilimovsky from the Upper Cretaceous Hell Creek Formation of Montana. That specimen (the only one known for the species) is a badly preserved, very poorly prepared skeleton showing little detail of the head region. It is interesting to note that the only known articulated fossil sturgeon skeletons (†Psammorhynchus longipinnis n. gen. and sp.; †Protoscaphirhynchus squamosus Wilimovsky; and a third, yet undescribed specimen) were apparently each independently discovered in the abdominal regions of hadrosaurian dinosaurs (as was the Cretaceous paddlefish †Paleopsephurus wilsoni MacAlpin). Perhaps hadrosaur carcasses provided the right combination of taphonomic factors to protect acipenseriform carcasses from damage in high energy aquatic environments predominantly preferred by sturgeons. In any case, based on known specimens, sediments within hadrosaurs appear to have been the main preservational medium for articulated fossil sturgeon skeletons in North America.

†Psammorhynchus longipinnis appears to be the sister taxon to the rest of Acipenseridae based on our preliminary analysis here. We will reevaluate this relationship elsewhere in our (Hilton, Grande, and Bemis) ongoing study of fossil and living Acipenseridae.

Three-dimensionally phosphatized, spherical fossils, interpreted as metazoan eggs and embryos on the basis of taphonomic features and cleavage patterns, are reported for the first time from the Cambrian of North America. These microfossils occur with a phosphatized biota of skeletonized fossils, including specimens indicative of the earliest Cambrian Anabarites–Protohertzina Zone in the Wernecke Mountains of eastern Yukon Territory, northwestern Canada. They range in size from 0.25 mm to more than 1.0 mm in diameter and can be referred to two genera, Olivooides Qian, 1977 and Archaeooides Qian, 1977. The North American discovery extends the biogeographic range of earliest Cambrian eggs and embryos from coeval successions in China and Siberia, suggesting a wide geographic distribution of these taxa, and emphasizes the crucial role of local environmental and taphonomic conditions in preserving this phosphatic window into the record of early animal evolution. In addition to previously reported taxa, the phosphatized biota also include indeterminate spheroids, fused clusters of Protohertzina siciformis Missarzhevsky, 1973, the enigmatic rodlike fossil Zhejiangorhabdion comptum Yue and Zhao, 1993, phosphatized fossils, including Paradoxiconus typicalis Qian et al., 2001, protoconularid Carinachites sp., and phosphatic tubes assigned to Hyolithellus cf. H. isiticus Missarzhevsky, 1969, cf. Pseudorthotheca sp., and ?Rugatotheca sp.

The distinctive, branched thrombolite, Favosamaceria cooperi new group and form, is found widely in the Great Basin, USA, where it is restricted to the Late Cambrian Saukia trilobite Zone. This thrombolite is distinguished by a hedgerow, mazelike organization of ridges similar to garden walls (maceriae) in plan view, branching of ridges into daughter ridges and columns, the polymorphic nature of dark, 1–4 mm mesoclots, and the relative consistency of maceria width (approximately 1 cm). As a group, Favosamaceria is found elsewhere in Upper Cambrian strata of the Argentine Precordillera, Appalachians, and Upper Mississippi Valley, as well as in Lower Ordovician deposits of the Canadian Arctic and Newfoundland. The distribution of the group around Laurentia illustrates the use of microbialites in biogeographic studies.

A detailed taxonomical description of scleractinian corals from the Maastrichtian of Mexico (Cardenas Formation) is given for the first time. the coral association comprises 16 taxa which belong to 9 families: Dictuophyllia conferticostata (Vaughan), Cladocora jamaicaensis Vaughan, Cladocora gracilis (d'Orbigny), Antiguastrea cellulosa (Duncan), Multicolumnastraea cyathiformis (Duncan), Placocoenia major Felix, Siderastrea vancouverensis Vaughan, Siderastrea adkinsi (Wells), Goniopora sp., Actinacis haueri Reuss, Actinacis parvistella Oppenheim, Actinhelia elegans (Goldfuss), Meandrophyllia oceani (de Fromentel), Dermosmiliopsis orbignyi Alloiteau, Trochoseris aperta Duncan, and Cyathoseris formosa d'Achiardi. the corals described herein were collected from mixed coral-rudist and coral-dominated assemblages in the Arroyo de la Atarjea, and one unnamed riverbed which lithologically correspond to the Arroyo de la Atarjea section, both of which belong to the upper member of the Cardenas Formation. On the genus level, 94% of the Mexican fauna corresponds to the Maastrichtian coral assemblages of Jamaica. Moreover, the Cardenas fauna shows close affinities to both Upper Cretaceous coral associations of central Europe and the Caribbean, as well as to Lower Tertiary faunas of Central America and the Caribbean. On the species level, 68.8% of the Cardenas corals are known from Lower Tertiary strata of Central America, the Caribbean, South America, Asia, European/Mediterranean region, and/or southeastern parts of the USA.

The remarkable brachiopod Xianshanella haikouensis, from the Early Cambrian Chengjiang Lagerstätte, was briefly reported based on only two extraordinarily preserved specimens. Details of valve interiors remain unknown due to a lack of available material. We herein reillustrate the holotype of X. haikouensis, and, on the basis of many additional specimens from the type locality, provide further information on this brachiopod taxon, including shell ornamentation, a U-shaped digestive tract, mantle canal systems, lophophores, muscle scars, and well-defined visceral areas in the valves. This exceptional brachiopod is characterized by a biconvex, rounded, knob-shaped shell lacking visible pseudointerarea in the valves, an elongate and muscular pedicle, and, especially, its possession of exceptional setal fringes. A restudy of a number of new specimens justifies assigning Xianshanella to the family Obolidae. The elongate and horny setae of X. haikouensis, coupled with the massive pedicle in many cases with its end attached to shells of other animals, indicate that this species was an epibenthic, sessile suspension feeder, attached by a pedicle.

Scrippsiella trifida Lewis, 1991 ex Head, 1996 is a nontoxic marine calciodinelloidean dinoflagellate whose resting cyst has a distinctive wall containing large, erect, trifurcate, recurving calcareous processes that separate two organic layers. We show that the organic wall layers of living Scrippsiella trifida cysts are resistant to acetolysis and can therefore potentially fossilize, and we report on abundant Scrippsiella trifida cysts from latest Pleistocene and early Holocene marine sediments off eastern Canada, representing the first confirmed fossil discovery of this species in the North Atlantic. A reappraisal of late Quaternary palynological records now shows that the organic remains of Scrippsiella trifida cysts have been widely misidentified as cysts of Alexandrium tamarense (Lebour, 1925) Balech, 1985, a goniodomacean (and hence noncalcareous) dinoflagellate and major cause of paralytic shellfish poisoning in humans. The morphology of these two cyst types is contrasted, and the modern and fossil distribution of Scrippsiella trifida cysts in sediments of the North Atlantic and adjacent areas is now clarified. It is apparent from this distribution that Scrippsiella trifida favors neritic environments characterized by cool winters and relatively warm (14°–25°C) summers. Extremely high fluxes of S. trifida cysts in nearshore areas off Nova Scotia and southern Greenland during deglaciation and early postglacial time (14–7 ka) have no modern analog but may signal a reduction in salinity caused by meltwater discharge. In general, the organic walls of calcareous dinoflagellate cysts are more common components of palynological assemblages than hitherto realized.

An extensive faunule of silicified calcareous sponges has been recovered from the Upper Guadalupian Reef Trail Member of the Bell Canyon Formation, from the Patterson Hills, in the southwestern part of the Guadalupe Mountains National Park in western Texas. This is the youngest silicified faunule of Permian sponges known from that area, and possibly the youngest from North America. It includes the hypercalcified ceractinomorph “sphinctozoans” Amblysiphonella sp., Tristratocoelia rhythmica Senowbari-Daryan and Rigby, 1988, Colospongiella permiana n. gen. and sp., Exaulipora permica (Senowbari-Daryan, 1990), Parauvanella minima Senowbari-Daryan, 1990, and the “sphinctozoans” Girtyocoelia beedei (Girty, 1909), Sollasia ostiolata Steinmann, 1882, Sollasiella reticulata n. gen. and sp., Ramosothalamiella divaricata n. gen. and sp., and Spica texana n. sp. Also present are Guadalupia zitteliana Girty, 1909, Guadalupia minuta n. sp., Lemonea cylindrica (Girty, 1909), and Lemonea micra Rigby, Senowbari-Daryan, and Liu, 1998. Aspiculate calcareous sponges include the “inozoids” Preperonidella rigbyi (Senowbari-Daryan, 1991), ?Djemelia sp., Radiotrabeculopora virga n. sp., Daharella ramosa Rigby and Senowbari-Daryan, 1996, Daharella pattersonia n. sp., Daharella crassa n. sp., and Newellospongia perforata n. gen. and sp. The problematic Lercaritubus problematicus Flügel et al., 1990 is tentatively included with the “inozoids.”

The new siliceous protomonaxonid demosponge Monaxoradiata lamina n. gen. and sp., is a moderately common sponge from the member. The new siliceous lithistid demosponges Chiastocolumnia cylindrica n. gen. and sp., Dactylites obconica n. sp., and Dactylites magna n. sp., the large hexactinellid sponge Toomeyospongia gigantia Rigby and Bell, 2005, and the new lyssacinosid Flexuospiculata hexactina n. gen. and sp., along with isolated large hexactines, are associated with these silicified calcareous sponges from the Reef Trail Member. Toomeyospongia gigantia Rigby and Bell, 2005, described earlier, is the only large complete hexactinellid sponge that is part of the Reef Trail Member assemblage.

The problematical Pulsatospongia obconica n. gen. and sp., whose taxonomic position is uncertain, along with an encrusting possible inozoid sponge, and spicule-lined ?burrows are also described as part of the fossil assemblage.

Significant faunal similarity occurs between this assemblage and those from several areas within the Paleo-Tethys Sea, especially with those from the Djebel Tebaga area of Tunisia. This suggests significant faunal exchange between the two regions, possibly resulting from strong trans-Panthalassan equatorial currents and a significant anti-cyclonic gyre within the Paleo-Tethys basin.

Abundant silicified polyplacophorans from numerous localities in the Ordovician in Kentucky and other localities in Virginia, Wisconsin, and Minnesota are described systematically. New species are: Spicuchelodes cressmani, Calceochiton floweri, Preacanthochiton baueri, Orthriochiton recavus, Helminthochiton blacki, H. marginatus, and Alastega martini; new genera and species are: Listrochiton weiri, Litochiton crebatus, and Amblytochiton incomptus; and new families are Litochitonidae and Alastegiidae. Hemithecella expansa Ulrich and Bridge in Butts, 1941 and Chelodes cf. C. mirabilis (Butts, 1926), from the Chepultepec Formation in Virginia are also described. Comparisons are made with Chelodes whitehousei Runnegar, Pojeta, Taylor, and Collins, 1979 from Australia and Calceochiton hachitae Flower, 1968 from New Mexico.

Listings of the fauna associated with the chitons are given for the Kentucky occurrences; taphonomic discussions of these are included.

Fossiliferous deposits of the Greenhorn Limestone (Upper Cretaceous) are found on the Comanche National Grassland in southeastern Colorado. The lowest portion of the Greenhorn Limestone, the base of the Lincoln Limestone Member, contains calcarenite beds rich in disarticulated remains of marine vertebrates. We examined the composition of the vertebrate paleofauna from one particular location (Tobe locality) through surface collecting and acid solution of rocks. The paleofauna is taxonomically diverse, consisting of 22 chondrichthyans, at least 15 osteichthyan fishes, and six aquatic reptiles. Molluscan taxa indicate that the basal Lincoln Limestone in southeastern Colorado was deposited sometime between middle Middle Cenomanian (ca. 95 Ma) and late Middle Cenomanian (ca. 94.7 Ma), and the composition of the vertebrate fauna (primarily chondrichthyan taxa) agrees with this interpretation. The Tobe locality was situated far from the shorelines of the Western Interior Seaway, with relatively high-energy waves impinging upon the seafloor, concentrating biogenic remains. Fossil remains within the calcarenite appear to have undergone minor time-averaging, based upon erosional rounding and breakage present in numerous specimens. Nevertheless, the deposit contains one of the best representative Middle Cenomanian vertebrate communities so far described from the Western Interior Seaway of North America. Considering that the paleofauna consists of taxa diverse in size, morphology, and inferred ecology, the trophic structure of the paleocommunity was probably complex.

A new multicostate rhynchonellid brachiopod Jakubirhynchia occurs in the Hettangian (Early Jurassic) carbonate deposits of the West Carpathians. A comparison with externally similar multicostate rhynchonellids from the Hettangian–Sinemurian carbonate deposits of the Alps shows their congeneric and conspecific status, indicating relatively wide regional distribution in the Early Jurassic of the western Tethys.

Diagnostic characters include conjunct deltidial plates, divided, vertically inclined inner hinge plates forming sessile septalium, and subfalciform crura with relatively complex, serrate terminations and broad outline in lateral view. Although the shape of hinge plates and crura may vary according to shell convexity and shell orientation during serial sectioning, two-dimensional restorations of cardinalia and crura show their distinctive morphology. It is important to note that some of the cardinalia details and crural shape can be detected only with very short between-section distances. Based on external characters, Jakubirhynchia is a homeomorph to another multicostate rhynchonellid, Calcirhynchia, typical of the Hettangian and Early Sinemurian of the northwestern Europe province and reported also from the Tethyan province. This suggests that original distribution of Calcirhynchia might not be so wide and postextinction multicostate rhynchonellids were taxonomically more diverse as was previously supposed. Jakubirhynchia consistently occupies offshore, low-energy, micritic-rich habitats below storm wave base. It is the first reported Hettangian member of the family Basiliolidae and may bridge the gap between the Carnian Veghirhynchia and Early Jurassic basiliolids. Preextinction, Norian and Rhaetian brachiopods that are close morphologic relatives of Jakubirhynchia are known from outside the western Tethyan area only.

The biostratigraphically important genus Hunnegraptus is recognized for the first time in the Marathon region, West Texas, based on restudy of the type material of Didymograptus novus Berry, 1960. The late Tremadoc Hunnegraptus Zone is the oldest unequivocally recognized graptolite zone in the Marathon region, underlain by faunas with nondiagnostic adelograptids. Hunnegraptus novus (Berry) shows a sicular bitheca, dichograptid stipes, and delayed first distal dichotomies as the most important rhabdosome characteristics. Hunnegraptus Zone faunas are more widely distributed in North America than previously realized and an immensely useful discovery for biostratigraphic correlation of this late Tremadoc time interval.

Caridroit, De Wever, and Dumitrica (1999) promoted stauraxon (Radiolaria) to an order, order Latentifistularia, and De Wever et al. (2001) proposed a classification using family and genus levels. However, the taxonomy of this order in genus level is still problematic because some genera were named according to broken specimens. A radiolarian fauna with a high diversity was collected from the late Changxingian in southern Guanxi, China. These specimens are very well preserved so that they are rare material for roundly describing the characters of some genera. They are identified as 42 species belonging to 16 genera and 5 families. Fifteen new species and one new genus are described, some genera are discussed, and some species are revised.

The morphologic expression of microenvironmental variation is difficult to document in fossil ecosystems and therefore is poorly understood. However, documentation of environmental sources of variation in the phenotype is essential for meaningful studies of microevolution and speciation. A fossil assemblage from the Mississippian (Valmeyeran) Warsaw Formation near St. Louis, Missouri, provides necessary conditions to evaluate microenvironmentally induced phenotypic variation in the Paleozoic trepostome bryozoan Leioclema punctatum (Hall, 1858). Specimens of L. punctatum, found as fragments in 22 discrete piles, were collected in their entirety from a weathered surface. Each pile contained 20—200+ branch fragments of L. punctatum, which were all originally attached to large, soft-bodied hosts (sponges?). Multiple attachment bases were found in most piles, indicating that 1) multiple L. punctatum colonies (genotypes) are represented in each pile, and 2) each pile represents a near contemporaneous, relatively short-lived microcommunity. Morphological characters were measured (four per section) from two branches for each of two specimens from five separate piles. Results from completely random, nested, one-way ANOVA indicate that no highly significant differences exist among microcommunities or between colonies for any measured characters, but that significant variation exists within colonies and among colonies in the same microcommunity (pile). That is, submicroenvironmental variation, within and among colonies, can play a greater role in morphogenesis than environmental heterogeneity within a given environmental setting (undifferentiated facies). Microenvironmental factors affect the size and shape of mesopores (space-filling structures) more than other morphological characters.

Results are encouraging for the general application of the preserved fossil phenotypes as proxies for biological species. This conclusion is based on the absence of systematic variation at microenvironmental levels, measurable here, but not normally distinguishable in paleontological and sedimentological studies. Correct attribution of fossil species assumes, however, that the source and the relative importance of the low-level (submicroenvironmental) variation on development/ontogeny is recognized and attributed appropriately. Results call for a reevaluation of the application of within versus among colony variation used as a proxy for environmental stability.

Radiolaria of the families Haplotaeniatumidae Won, Blodgett, and Nestor, 2002 and Inaniguttidae Nazarov and Ormiston, 1984 were recovered from the Llandovery and lower Wenlock of the Cape Phillips Formation on Cornwallis Island, Nunavut, Canada. Three new species of haplotaeniatumids are described. Haplotaeniatum fissura n. sp. is diagnosed by a densely constructed outer layer around a less dense interior; Haplotaeniatum nunavutensis n. sp. has small, circular pores separated by wide lattice bars; and Orbiculopylorum granti n. sp. possesses robust external spines. Haplotaeniatumids described in open nomenclature are Haplotaeniatum labyrintheum?, Haplotaeniatum aff. cathenatum, Haplotaeniatum cf. raneatela, Haplotaeniatum species A, Orbiculopylorum aff. adobensis, Orbiculopylorum cf. marginatum and Orbiculopylorum species A. Gyrosphaera Noble and Maletz, 2000 is synonymized with Haplotaeniatum. The Inaniguttidae are assigned to Plussatispila n. gen. The genus is diagnosed by two, well-spaced lattice shells and at least seven main spines; additional shells may be present. Plussatispila magnilimax n. sp. has a total of four shells, and P. cornwallisensis n. sp. a total of three. Plussatispila delicata n. sp. has only the two fundamental shells of the genus and is slightly more delicate than the other inaniguttids. Plussatispila pellicia n. sp. possesses weakly developed spines and may have additional irregular layers.

Numerous Early Cambrian corals or “coralomorphs,” as they are often classified, are recorded from North America, Australia, and Siberia. A new Early Cambrian coral, Harklessia yuenglingensis n. gen. and sp., is found in conjunction with archaeocyathan-microbial reefs in Esmeralda County, southwestern Nevada. The coral-bearing reefs are within quartzic, trilobite-rich packstone beds in the upper portion of the Harkless Formation (Bonnia–Olenellus Zone). Coralla are constructed by subpolygonal to polygonal, cerioid, close-packed corallite tubes. Coralla average 12 cm in height by 18 cm in diameter with individual corallite tubes ranging from 1.2 to 3.2 mm in diameter. Corallites are greater than 25 mm in length. Septa and tabulae are not present.

Many of the Early Cambrian corals previously described have attributes of the class Anthozoa and subclass Zoantharia, with some specific similarities to tabulate corals. Harklessia yuenglingensis is placed confidently within the class Anthozoa, subclass Zoantharia because its morphological characteristics indicate an affinity to true corals, but whether H. yuenglingensis is a tabulate coral remains uncertain.