The Upper Proterozoic (ca. 700–800 Ma old) Backlundtoppen Formation, northeastern Spitsbergen, preserves an abundant and varied record of ancient microbial life. Five distinctive microfossil assemblages occur in five equally distinct sedimentary settings; differences among the assemblages appear to reflect original ecological heterogeneity, although taphonomic circumstance may contribute to some distinctions. Microfossil assemblages occur in: oncolites, oolites, and pisolites; stratiform stromatolites and associated intraclastic rudites; partially silicified micrites; and siltites interbedded with quartz arenites. Individual assemblages contain one to eight differentiable taxa; a minimum of 17 distinct populations is present in the formation as a whole. Additional microbial community diversity can be inferred from the presence of domal, columnar, pseudocolumnar, and coniform stromatolites, none of which contains microfossils. On the basis of macrostructure, four stromatolite types appear to be present, but only three distinct mat-building communities can be inferred from microstructural features. Eohyella elongata n. sp., a euendolithic cyanobacterium found in silicified pisolites, is described as new.

The sandstone facies of the Pliocene Rio Banano Formation of eastern Costa Rica contains benthic foraminifera indicative of an open marine, current-swept, neritic depositional environment. These sandstones and associated siltstones are placed in Zone N18 on the basis of overlapping ranges of planktonic foraminifera, particularly Globigerinoides obliquus extremus and G. ruber, and a short-ranging ostracode species, Radimella ovata. One hundred and eight species of benthic foraminifera have been identified from the formation. A multiple-group-component factor analysis of abundance distributions of several dominant or common species (Amphistegina gibbosa, Articulina mayori, Cassidulina laevigata, C. subglobosa, Cibicidoides floridanus, Elphidium discoidale, Hanzawaia concentrica, Pararotalia sarmientoi, Pseudononion basispinata, Quinqueloculina lamarckiana, Rosalina globularis, and Trifarina angulosa) in the type section aided in the recognition of three benthic foraminiferal assemblages related to environmental parameters. An open marine, shallow, sandy continental shelf environment is suggested by the first assemblage. This is considered the typical depositional environment of the unit. The second and the third assemblages, suggesting an inner littoral environment and the proximity to a reef, respectively, also indicate introduction of significant amount of transported material into the thanatotopes.

Twenty-two species of Early Permian colonial rugose corals belonging to 12 genera from 10 locations in the Stikine River area in northwestern British Columbia, Canada, are described. These include three new species of Fomichevella (F. magna, F. southeri, F. bamberi); two species of Heintzella; five species of Heritschioides, of which three are new (H. bagleyae, H. garvinae, H. hoganae); two new species of Paraheritschioides (P. jennyi, P. wickenae); one new species questionably assigned to Kleopatrina (K.? stikinensis); two new species of Petalaxis (P. guaspariniae, P. neriae); and two new species of Lytvophyllum (L.? mongeri, L. wersoni). In addition, five new species assigned to five new genera are here named Eastonastraea complexa, Fedorowskiella simplex, Pararachnastraea lewisi, Stikineastraea thomasi, and Wilsonastraea rigbyi.

These corals occur in rocks forming part of the Stikine terrane, the largest tectonostratigraphic unit in western Canada. This coral fauna shows a very close affinity with that of the Lower Permian McCloud Limestone of the eastern Klamath Mountains of northern California, and there is some similarity to the Coyote Butte fauna of central Oregon. Several species compare most closely with species from Spitsbergen, but there are few similarities with any cratonal North American faunas and none with Tethyan faunas.

Environmental conditions affect both the character and variability of developmental patterns (=astogeny) within each of four species of Ordovician bryozoans. Regressions between pairs of stereological measurements for populations from both high-and low-diversity habitats differ significantly in 79 percent of all comparisons. Deviations from a rigid pattern of development, measured as dispersion from regression, were greater in species populations from low diversity settings in 77 percent of comparisons. Therefore, both developmental patterns and their variability differ intraspecifically along a diversity gradient in representatives of four bryozoan families. Additionally, dispersion values were larger in younger rather than older colonies in two species irrespective of diversity level, thus suggesting an age-related reduction in variation.

Changes in developmental trajectories indicate that colonies from low-diversity settings are generally paedomorphic relative to conspecific populations from high-diversity habitats. The heritability of these characters and developmental patterns, estimated using variance partitioning techniques, is greater in high-diversity associations. These findings suggest that character state modifications dependent upon astogeny, or a consequence of astogenetic modifications, are more heritable in high-diversity settings. However, if the environment can cause facultative heterochrony, the possibility of fixing such patterns in subsequent generations is increased, although the mechanism for accomplishing this is presently unknown.

The brachiopod Pentamerus oblongus is especially abundant in the Lower Silurian Rytteråker Formation, which occurs widely throughout the Oslo region in southern Norway. Alternating thin limestones and shales typically occur in a shallowing-upward sequence ending in a massive grainstone often rich in tabulate corals and stromatoporoids. In the lower beds, colonization by pentamerid populations was enhanched by prior emplacement of an orthotetacean shell pavement over the clastic sea bed. Individual Pentamerus size decreases with increasing disturbance of populations or their fragmentation as lag deposits nearer the stratigraphic level of the massive grainstone. The frequency of specific storm events and the changing depth to the sea bed may be indexed according to the average size of pentamerid shells in a given population and the degree to which the population is disturbed. Preservation of prominent growth lines (assumed to be annual) suggests storms stirred the sea bed in deeper waters on an 8–10 year cycle. In shallower waters, storms more regularly disturbed the sea bed every 2–3 years. These data corroborate the interpretation that the Pentamerus community inhabited marine waters below fair-weather wave base, but still within reach of storm wave base.

Small gastropod opercula have been found at one locality each in the Desmoinesian and Virgilian of north-central Texas. Because of their general shape and concentric growth, these opercula are placed within the Neritacea. One form probably is the operculum of Trachydomia. Four other forms, two of which are morphologically quite similar but from different ages, probably belong with Naticopsis sensu lato.

A new genus, Popenoeum, is proposed for a clade of Upper Cretaceous through lower Eocene pseudolivine gastropods found in North and South America, West Greenland, western Europe, and southern India. Popenoeum n. gen. is characterized by tabulate whorls with a prominent subsutural canal, collabral costae that terminate as tubercles on the body whorl shoulder, and closely spaced fine to strong spiral cords.

The type species, Popenoeum maritimus n. sp., is from the lower Paleocene (Danian) portion of the San Francisquito Formation, southern California, and from the upper Paleocene (Thanetian) Sepultura Formation, Baja California. Popenoeum maritimus bajaensis n. subsp. is also present in the Sepultura Formation.

Other species and subspecies in the clade include Popenoeum sp. (Toulmin) and P. scalina Heilprin from Alabama; P. mutabilis mutabilis (Woods) and P. mutabilis woodsi (Olsson) from northwestern Peru; P. aff. P. maritimus from West Greenland; P. brevis (Doncieux) and P. prima (Defiance) from France; P. chavani (Glibert), P. robusta (Briart and Cornet) and P. briarti (Vincent) from Belgium; and P. subcostata (Stoliczka) from southern India. The earliest species is P. subcostata, and it is the only Cretaceous species. The youngest form is P. mutabilis woodsi, and it is the only Eocene species. The new genus reached its peak during the Paleocene.

The ammonite species Puzosia (Mesopuzosia) densicostata Matsumoto, Kitchinites (Neopuzosia) japonicus Spath, Anapachydiscus cf. A. nelchinensis Jones, Menuites cf. M. menu (Forbes), Submortoniceras chicoense (Trask), and Baculites cf. B. boulei Collignon are described from Santonian–Campanian strata of western Canada and northwestern United States. Stratigraphic occurrences and ranges of the species are summarized and those taxa important for correlation with other areas in the north Pacific region are noted.

The burrow structures of Heterocerus brunneus Melsheimer and its larvae are described from both field (northeastern Kansas) and laboratory habitats. These are further interpreted in light of known North American heterocerid biology. Two important observations are that significant features of any one burrow varied with the consistency (especially the water content) of the substrate, and that different insects were making superficially similar burrows at the same field site. It would require exceptional preservation, or associated body parts, to positively identify fossil traces of these structures as heterocerid burrows, but their general pattern should be readily recognized as foraging traces in even the most degraded preservations.

The Fossil Hill Member of the Prida Formation (Fossil Hill, Nevada) yields one of the most continuous records of Middle Triassic conodont evolution currently known. Because of different taxonomic viewpoints, this record has been alternately interpreted to represent either morphological stasis or gradual, biostratigraphically significant morphogenesis. Univariate and multivariate morphometric analysis of 18 successive Neogondolella Pa element populations suggests that the majority of specimens at Fossil Hill (including N. constricta emend. sensu Nicora and Kovacs, 1984) belong to a single, morphologically diverse species, Neogondolella mombergensis (Tatge). Time series of individual character means from 18 stratigraphic horizons in the Fossil Hill display nondirectional morphologic trends for which a random walk model cannot be rejected. Time series of transformed multivariate means constitute biologs that may prove useful in regional correlation.

Currently some controversy exists in the micropaleontological community concerning the statistically correct number of counts required for quantitative examinations, particularly with respect to the effect of variations in the number of species between samples and the significance of varying fractional abundances on the reliability of results. This analysis of the various statistical methods used to determine the number of required counts has shown that the number of species has no relationship to the number of counts required to measure accurately fractional abundances. As part of the study, logarithmic contours plotting percentage abundance against the total number of specimens, which provide abundance errors at a 95 percent confidence level, have been generated. The plot is displayed logarithmically to emphasize the significance of rare microfossil elements that dominate most assemblages, and which are important in many paleoenvironmental studies. Based on the plot, it is recommended that researchers utilize counts of at least 50 for indicator species having a fractional abundance of approximately 50 percent or greater; 300 counts for species which comprise approximately 10 percent of a sample; 500–1,000 counts for species that make up 5 percent of a sample; and counts of several thousand for defining species that comprise 1 percent of a sample. It is important to note, however, that where similar biofacies are involved, higher counts are required to accurately distinguish them. It is also recommended that researchers include fractional error abundances with their estimated abundances to provide an indication of their accuracy.

Chondrophorines have a long but exceedingly sporadic history: they dot the late Precambrian and Paleozoic and are common in modern oceans, but have not been reported from the Mesozoic or Cenozoic save for a possible Triassic occurrence (Stanley, 1986) and a single Cretaceous appearance (Stanley and Kanie, 1985). Stanley (1982) suggested that much of the fossil record of the group may languish unrecognized and misidentified in museum drawers because of its generally molluscanlike aspect and poor representation in the literature. This suspicion is validated by the discovery of a velellid chondrophorine pneumatophore in the vertebrate collections of the University of California Museum of Paleontology (UCMP).

Articulated specimens of polyplacophorans are rare in the geological record, most being found as isolated valves. When found, it is useful to illustrate articulated specimens to provide a basis for making correct associations of isolated valves, to substantiate valve associations already proposed, and to determine valve order and amount of valve overlap.

Reports of Mississippian polyplacophorans from North America are rare. To date only three species, Gryphochiton parvus (Stevens, 1858) and G. elevatus (Kues, 1978), from the Salem Limestone in Indiana, and Elachychiton juxtaterminus Hoare and Mapes, 1985, from the Imo Formation in Arkansas, have been recognized (Smith and Hoare, 1987). Lobarochiton anomalus (Rowley, 1908), from the Louisiana Limestone in Missouri, is now believed to be Devonian in age. European reports of Lower Carboniferous polyplacophorans are much more common, at least 29 species (Hoare and Smith, 1987). The location of any specimen in the Mississippian of North America becomes significant in filling out the geologic history of this taxonomic group.

A recent review (Haman, 1988) of the publication “Foraminiferal Genera and Their Classification” by Alfred R. Loeblich, Jr. and Helen Tappan, Van Nostrand Reinhold Company, New York, incorrectly indicated the date of its publication as “early 1988,” although adding, parenthetically, “The senior author refers to the publication date as December, 1987, A. R. Loeblich, Jr., January, 1988, written communication.”

Conodonts display higher specific gravity (2.84-3.10) than common minerals in sedimentary rocks. For several decades this property has been exploited to separate these microfossils from sediment residues using density separation techniques. Two heavy liquids commonly used, bromoform and tetra-bromoethane, are toxic (Sax, 1979; HaufTand Airey, 1980) and constitute a danger to human health. Tetrabromoethane is a known carcinogen (Brem et al., 1974). Both of these liquids should be abandoned in favor of nontoxic sodium polytungstate (Callahan, 1987; Merrill, 1987b; Krukowski, 1988). There are, however, some technical problems with its use because of relatively high viscosity and a tendency to recrystallize during separation. Another big disadvantage is also its price at $100 per kilogram. These problems may be considerably overcome by using polytungstate in the way described by Savage (1988).

Quick setting dental impression materials are nothing new in the paleontology laboratory. In a paleontological note published in the Journal of Paleontology on “The Use of Dental Impression Material For Molding Macrofossils” (Quilty & Williams, 1975), the products Xantopren and Optosil were introduced as a simple and fast method of obtaining precision molds in 1-3 minutes. Since the mid-1970's these products have been replaced by vinyl polysiloxanes.

In a letter dated April 29, 1988, Helen and Alfred R. Loeblich, Jr. kindly brought to my attention the fact that the newly proposed generic name Cribrella Gawor-Biedowa, 1987, is preoccupied by Cribrella Agassiz, 1836, by Cribrella Schmidt, 1862, and by Cribrella Cossman, 1906, hence requires a new name. Cribrella Gawor-Biedowa, 1987, type species Cribrella lacrima Gawor-Biedowa, 1987, thus is renamed here as Cribrebella Gawor-Biedowa, nom. nov.

The name Echinolampas duncani McNamara, 1987 (McNamara, 1987, p. 109-110, fig. 1A-C) was given to a Miocene cassiduloid echinoid species from Australia. J. Roman (Institut de Paléontologie, Muséum National d'Histoire Naturelle, Paris, France) has kindly alerted me to the fact that this name is already occupied by Echinolampas duncani Cotteau, 1891 (Cotteau, 1891, p. 162). Cotteau proposed this name as a replacement for Echinolampas obesa Duncan and Sladen, 1884, which was a junior homonym of Echinolampas obesus Bittner, 1880. The recently described Australian species is therefore a junior homonym of Echinolampas duncani Cotteau, 1891. Consequently a new name, Echinolampas laubei, is proposed as a replacement for Echinolampas duncani McNamara, 1987. It is named after G. C. Laube, in honor of his pioneering work on the Miocene echinoid faunas of Australia.