Hermit crabs have left a rich fossil legacy of epi- and endobionts that bored or encrusted hermit crab-inhabited shells in specific ways. Much of this rich taphonomic record, dating from the middle Jurassic, has been overlooked. Biological criteria to recognize hermitted shells in the fossil record fall within two major categories: 1) massive encrustations, such as encrusting bryozoans; and 2) subtle, thin encrustations, borings, or etchings that surround or penetrate the aperture of the shell. Massive encrustations are localized in occurrence, whereas subtle trace fossils and body fossils are common, cosmopolitan, and stratigraphically long-ranging. Important trace fossils and body fossils associated with hermit crabs are summarized here, with additional new fossil examples from the eastern Gulf Coast. Helicotaphrichnus, a unique hermit crab-associated trace fossil, is reported from the Eocene of Mississippi, extending its stratigraphic range from the Pleistocene of North America and the Miocene of Europe.

Charles D. Walcott's thin sections of the Middle Cambrian Burgess Shale of British Columbia, Canada, have yielded many specimens of the helically coiled microfossil Obruchevella delicata, as well as fragments of the cyanobacteria Marpolia and Morania, sphaeromorph acritarchs, and sclerites of the enigmatic metazoan Wiwaxia. Obruchevella of the Burgess Shale displays a spectrum of preservation styles ranging from tangled masses to well-developed helixes. All Obruchevella specimens are preserved in three dimensions, which suggests original skeletalization or early post-mortem mineralization of the organism. Morphologic analysis of Obruchevella supports an affinity with modern helical cyanobacteria. Study of all reported occurrences of Obruchevella indicates that: 1) the genus has been overly split into seventeen species; 2) no correlation between size and age of Obruchevella exists; and 3) most Obruchevella specimens are tightly coiled and have helix diameters four to six times their filament diameters.

Moderately well preserved Permian (late Wolfcampian, Leonardian, Guadalupian, and Djulfian) and Early(?) Triassic radiolarian faunas from sedimentary mélange cherts of the Grindstone terrane in central Oregon are nearly identical to coeval chert faunas in Japan. These Permian faunas are similar to those used in constructing the radiolarian zonations for Japan and the Tethyan regions. Although several Oregon taxa have been reported from limestone sequences in the central United States, most of the Oregon forms have only been found in cherty rocks and nearly half have not previously been reported from North America. Forty-two taxa belonging to 19 genera (Albaillella Deflandre, Deflandrella De Wever and Caridroit, Entactinia Foreman, Entactinosphaera Foreman, Follicucullus Ormiston and Babcock, Haplentactinia Foreman, Hegleria Nazarov and Ormiston, Ishigaum De Wever and Caridroit, Kashiwara Sashida and Tonishi, Latentibifistula Nazarov and Ormiston, Latentifistula Nazarov and Ormiston, Nazarovella De Wever and Caridroit, Neoalbaillella Takemura and Nakaseko, Parentactinia Dumitrica, Praedeflandrella Kozur and Mostler, Pseudoalbaillella Holdsworth and Jones, Pseudotormentus De Wever and Caridroit, Quinqueremis Nazarov and Ormiston, and Triplanospongos Sashida and Tonishi) are systematically treated. Co-occurrences of some species in Oregon indicate that their ranges in North America may differ from those in Japan. This paper also contains the first illustrated record of Early(?) Triassic radiolarians from North America.

A method of phylogenetic inference is proposed for taxa that are known from large samples spaced closely in time. The method employs elements of cladistic and stratophenetic methods, and consists of four steps. 1) Morphologically homogeneous clusters are recognized within temporally and geographically constrained samples. 2) Temporally disjunct and geographically dispersed taxa are recognized, and their anagenetic evolution and geographic variation documented. 3) A character matrix is constructed for the taxa and analyzed cladistically. 4) Resulting cladograms are used to construct a phylogenetic tree with additional input from temporal, morphological, ecological, and geographical data. This method supplements the use of cladistically analyzed morphological data with data that are not suited for cladistic analysis, and thus reduces the amount of unused data.

The new balanid subfamily Concavinae is based on the genus Concavus Newman, 1982, and includes five genera and 29 species-group taxa. The subgenera Concavus, Tamiosoma Conrad, 1856 (senior synonym of Menesiniella Newman, 1982), and Arossia Newman, 1982, are raised to generic rank. Two new genera, Chesaconcavus (type species Balanus concavus chesapeakensis Pilsbry, 1916) and Paraconcavus (type species Balanus concavus pacificus Pilsbry, 1916), are proposed, based on fossil and extant species from North America. New species include Tamiosoma advena from the Pliocene of southern Florida, Chesaconcavus rossi and C. santamaria from the middle Miocene of Maryland, C. myosulcatus from the upper Miocene of Virginia, Arossia newmani from the middle Miocene of Maryland, A. rubra from the upper Miocene of central California, A. aurae from the lower Pliocene of North Carolina, and Paraconcavus margaritanus from the upper Miocene of southern California. Concavines, a predominantly Northern Hemisphere group, appear in the late Oligocene in North America and Europe, diversify and spread rapidly in the Neogene, and, with the exception of a few eastern Pacific relicts, become extinct before the late Pleistocene.

Upper Cretaceous rocks of the Kuskokwim Group are exposed in a large region of southwestern Alaska and are mainly composed of deformed turbidite deposits that contain few fossils other than inoceramid bivalves. This paper documents the taxonomy of the inoceramids in the Kuskokwim Group, develops an inoceramid biostratigraphy based on known ranges in other regions, and analyzes biogeographic patterns, paleoecology, and depositional history of the Kuskokwim Group.

Most of the inoceramid bivalves present in the Kuskokwim Group are of Cenomanian and Turonian age, and an assemblage of species typical of late Turonian age rocks is particularly well developed. Only two localities appear to be as young as Santonian age. The following 16 species or subspecies are discussed and illustrated in detail: Birostrina tamurai Matsumoto and Noda, Inoceramus virgatus Schlüter, I. pennatulus Pergament, I. pictus minus Matsumoto, I. cf. I. yabei Nagao and Matsumoto, I.? sp. aff. I. costatus Nagao and Matsumoto, I. hobetsensis Nagao and Matsumoto, I. longealatus Tröger, I. frechi Flegel, I. waltersdorfensis waltersdorfensis Andert, I. cf. I. waltersdorfensis hannovrensis Heinz, I. kuskokwimensis n. sp., Mytiloides cf. M. opalensis (Böse), M. teraokai (Matsumoto and Noda), M. cf. M. incertus (Jimbo), and Sphenoceramus naumanni (Yokoyama). In addition, a specimen with affinities to Mytiloides striatoconcentricus carpathicus (Simionescu) and a specimen that may belong to the I. (Cremnoceramus?) rotundatus–I. (C.) erectus lineage are illustrated.

Most of the taxa present in the Kuskokwim region are found in other regions of the North Pacific, particularly Japan and eastern Siberia, or are found throughout the Northern Hemisphere. Only one species, I. kuskokwimensis n. sp., is new and may be endemic. North Pacific taxa are predominant in the Kuskokwim region, but intervals near the Cenomanian–Turonian Stage boundary and in the upper Turonian contain taxa characteristic of Europe and the Western Interior basin of North America; some of these taxa have not been recorded previously in the North Pacific region. Turonian heteromorph ammonite assemblages associated with inoceramids in the finer grained facies of the Kuskokwim region are similar to those found in coeval rocks of Japan and Germany.

The depositional area of the Kuskokwim Group can be broken into two northeast-trending subbasins, the Kuskokwim River subbasin to the northwest and the Mulchatna River subbasin to the southeast, connected by the Nushagak Hills corridor. Within the Kuskokwim River subbasin, deposition apparently started earlier in the north (middle Cenomanian) than in the south (late Cenomanian to early Turonian), and prograding deltaic sedimentation along the western margin also appears to have started earlier in the north. No marine fossils younger than latest Turonian to earliest Coniacian are known from the Kuskokwim River subbasin. The youngest fossils identified are Santonian in age and are from deep-water deposits in the Nushagak Hills corridor. Few fossils are known from the Mulchatna River subbasin and age control is limited.

Mickwitziids are a unique group of brachiopods, known exclusively from the Lower Cambrian. Herein are described the new species Mickwitzia lochmana and M. multipunctata; both species are from southwestern North America. Mickwitzia muralensis Walcott, 1913, the largest mickwitziid, is reported here for the first time from the United States. This paper also discusses the distribution of mickwitziids, their shell structure, and the possible functions of mickwitziid punctae.

Dolabrosaurus aquatilis n. gen. and sp., a small amphibious or aquatic reptile from the Upper Triassic Chinle Formation of north-central New Mexico, is described on the basis of portions of the vertebral column and partial fore- and hindlimbs of a single specimen. Comparison with other Triassic reptiles indicates that D. aquatilis is most closely related to Drepanosaurus unguicaudatus, a small, enigmatic lepidosauromorph from the Upper Triassic Zorzino Formation of the Italian Alps. Both species are assigned to a new family, Drepanosauridae, with Dolabrosaurus recognized as more primitive in some aspects of its vertebral and pedal morphology. The precise assignment of Drepanosauridae within the Lepidosauromorpha remains uncertain.

Remarkably well-preserved specimens of Marocella Geyer, 1986, from the Lower Cambrian Shackleton Limestone of Antarctica show that although affinity with chondrophorine cnidarians is improbable, its rigid caplike shell also is unlike that of any known mollusk. Association with sclerite-bearing taxa cannot be ruled out, but at present the phylogenetic affiliation of the genus remains equivocal.

Carinachitiids, hexangulaconulariids, and Punctatus are distinctive and abundant components of early skeletal faunas from the Lower Cambrian of South China. Carinachitiids are redescribed on the basis of Carinachites spinatus from Kuanchuanpu, Shaanxi, and C. tetrasulcatus and C. curvatornatus from Emei, Sichuan. Tubes of all species are characterized by pronounced quadriradial symmetry, but whereas C. spinatus and C. curvatornatus generally have prominent ornamentation consisting of transverse ribbing, that of C. tetrasulcatus is much more subdued. Neither apex nor well-defined aperture is evident in any of the carinachitiids. Hexangulaconulariids are redescribed on the basis of Arthrochites emeishanensis from Emei and Hexaconularia sichuanensis from Kuanchuanpu. In common with the carinachitiids, the former species shows wide morphological variability. The tubes expand rapidly from a blunt apex, bear prominent ribbing, and possess variably developed lateral grooves that impose a quasi-hexaradial symmetry. Hexaconularia sichuanensis is described from fragmentary material with prominent ribbing and well-defined lateral grooves. Punctatus emeiensis has a tapering ribbed cone, with a stellate ornamentation adapically that is replaced by longitudinal ribbing towards the aperture. Carinachitiids and hexangulaconulariids are widely regarded as related to conularids, and this proposal receives additional support here. An external abortive ?borehole in a specimen of Carinachites also supports the tubicolous interpretation of these fossils. An alternative suggestion that carinachitiids and hexangulaconulariids represent the internal rachis of a sea-pen is also considered. The affinities of Punctatus are more speculative, but the genus may be related to the other two groups. The ecology of Punctatus, however, remains problematic.

Solitary rugose corals (Cnidaria, Rugosa) are common to abundant in the calcareous Box Member of the late Famennian Percha Shale (Lower expansa Zone) of southwestern New Mexico; the Box is best developed in the western part of the Percha outcrop belt. The corals include a number of forms characteristic of Strunian faunas throughout the world. Recognized here are Gorizdronia sp. cf. G. tenuis Rozkowska, Campophyllum? ursinum n. sp., Caninia cooperi n. sp., Siphonophyllia? folia n. sp., S.? corbicula n. sp., “Bothrophyllum” argenteum n. sp., “B.” argenteum argenteum n. subsp., “B.” argenteum bilateralis n. subsp., “B.” argenteum dibunophylloides n. subsp., Arachnolasmella elytra n. sp., and Cyathoclisia sp. A. This fauna is clearly ancestral to Carboniferous genera and species. Percha species, where represented by large populations, are seen to be remarkably variable, especially in axial structure.

Reefs of the Middle Devonian Edgecliff Member of the Onondaga Formation in New York and Ontario, Canada, contain three distinct paleocommunities: the Phaceloid Colonial Rugosan Paleocommunity, the Favositid/Crinoidal Sandstone Paleocommunity, and the rare Delicate Branching Tabulate Paleocommunity. The reefs may be classified as mounds or composite structures based on the degree of intergrowth of the rugosan and favositid paleocommunities. Composite structures may be further subdivided into mound/bank, thicket/bank, and ridge/bank structures based on the degree of development of the rugosan paleocommunity. Geographic distribution of reef types suggests that these patterns of reef growth were controlled by water depth.

A vertebra from the Judith River Formation (Campanian) of Saskatchewan, found with other Upper Cretaceous vertebrate remains, is referred to the loon-like hesperornithiform Baptornis, and is the first recorded occurrence of this genus from continental deposits. It is also the first bird described from the Judith River Formation of western Canada.

A study of Upper Triassic (Norian) thalamid sponges (“sphinctozoans”) from the Pilot Mountains, Garfield Hills, and East Range, Nevada, reveals an abundance of calcified sponges of the suborder Porata Seilacher. Two new species, Polycystocoelia silberlingi n. sp. and Neoguadalupia? norica n. sp., are added to our knowledge of five thalamid sponge taxa previously known from Nevada. All specimens have been neomorphically altered to calcite in a manner implying an original aragonite mineralogy.

At the species level, the sponges show a restricted distribution. Nevadathalamia cylindrica (Seilacher) is a species also occurring in Sonora, Mexico, and previously known from the Yukon of Canada, but all other species are endemic to west-central and northwestern Nevada. At the generic level, similarities exist with species known from the Tethyan Realm, the Yukon, and south China. The genus Polycystocoelia has been known previously only from Hubei, China, and from the Yukon Territory, Canada. Neoguadalupia was previously known only from the Lower and Upper Permian of China. The occurrence of this genus in Nevada constitutes the first record of the genus outside of the Permian System of China.

Siliceous sterraster microscleres of the choristid demosponge, Geodia Lamarck, 1815, occur in outcrops of the lower Porters Creek Formation (Paleocene) near Moscow Landing on the Tombigbee River in southeastern Sumter County, Alabama. This is the first report of that sponge from the Cretaceous–Tertiary of the Gulf Coastal Plain. The initially opaline spicules have been converted to clinoptilolite, a Na-K-Ca zeolite.

Correlations exist between diversity and colonial growth pattern and variability in Paleozoic stenolaemate bryozoans. Habitats occupied by diverse communities contained colonies whose growth trajectories were different and were more highly constrained than those of low-diversity habitats. Because previous studies have not examined variability during colony growth, it was unclear whether observed variabilities were constant during growth (astogeny) or whether variability changed with age. Astogenetic trajectories and growth variability are here reexamined in populations of colonies of Heterotrypa ulrichi from the same high-diversity and low-diversity communities examined by Pachut (1989).

Growth trajectories of populations differ in both intermonticular and monticular regions of colonies for fundamental stereological characters. Total zooidal surface areas generally decrease during astogeny whereas zooidal densities increase. Surface areas per zooid also decrease with increasing age, but are consistently larger in monticular zooecia and in populations from low-diversity communities irrespective of the colony region sampled. These patterns of declining values are caused by increasing wall thicknesses, larger and more abundant mesozooecia and acanthostyles, and the development of maculae during colony growth. Larger values in low-diversity settings may have provided reproductive and feeding benefits necessary for survival.

Covariances reflect levels of morphological integration and are larger in populations from high-diversity communities in both intermonticular and monticular regions. Values differ more during early stages of growth (1–3) than later in astogeny (stages 4–5), and are consistently higher in intermonitulcar than in monticular zooecia. Lower levels of integration in monticules may be caused by spatial adjustments as the number of monticules increases across the expanding colony surface during growth. In general, stabilizing selection may have been weaker and less effective in establishing character covariance patterns in populations from low-diversity communities, perhaps because of greater environmental stress. These findings suggest that evaluations of astogenetic patterns and age-related changes in levels of morphological integration within a paleoenvironmental context are important in measuring species richness, in determining the direction of character evolution, and in assessing tempo and mode of evolutionary changes.

Even though Viriatellina gracilistriata (Hall) has been cited repeatedly, this work is the first modern description and illustration of the lectotype. Not only have the characters of the species not been well understood, the type locality and horizon for this species have been in error. Rare specimens associated with this species are described as a new species, Viriatellina porteri.