Silicified peritidal carbonates of the Mesoproterozoic Kotuikan and Yusmastakh Formations, Anabar Uplift, northeastern Siberia, contain exceptionally well-preserved microfossils. The assemblage is dominated by ellipsoidal akinetes of nostocalean cyanobacteria (Archaeoellipsoides) and problematic spheroidal unicells (Myxococcoides); both are allochthonous and presumably planktonic. The assemblage also includes distinctive mat-forming scytonematacean and entophysalidacean cyanobacteria, diverse short trichomes interpreted as cyanobacterial hormogonia or germinated akinetes, rare longer trichomes, and several types of colonial unicells. Although many taxa in the Kotuikan-Yusmastakh assemblage are long-ranging prokaryotes, the overall character of the assemblage is distinctly Mesoproterozoic, with its major features shared by broadly coeval floras from Canada, China, India, and elsewhere in Siberia.

Microfossils also occur in middle to inner shelf shales of the Ust’-Il'ya and lower Kotuikan Formations. Leiosphaerid acritarchs (up to several hundred microns in diameter) characterize this facies. As in other Mesoproterozoic acritarch assemblages, acanthomorphic and other complex forms that typify Neoproterozoic assemblages are absent.

The combination in Billyakh assemblages of exceptional preservation and low eukaryotic diversity supports the hypothesis that nucleated organisms diversified markedly near the Mesoproterozoic–Neoproterozoic boundary. The assemblages also demonstrate the antiquity of cyanobacteria capable of cell differentiation and suggest the importance of both changing peritidal substrates and evolving eukaryotes in determining stratigraphic patterns of Proterozoic prokaryotes. The permineralized assemblage contains 33 species belonging to 17 genera. Ten new species or new combinations are proposed: Archaeoellipsoides costatus n. sp., A. elongatus n. comb., A. dolichos n. comb., A. minor n. nom., A. crassus n. comb., A. major n. comb., A. bactroformis n. sp., Veteronostocale medium n. sp., Filiconstrictosus cephalon n. sp., and Partitiofilum yakschinii n. sp.

Review of collections in Prague and at Harvard University, supplemented by additional field observations, has allowed taxonomic updating and revision of Barrandian trinucleid trilobites. Genera identified are Bergamia, Declivolithus, Nankinolithus, Tretaspis, Marrolithus, Deanaspis, and Onnia. One earlier described species is assigned to the new genus Marekolithus.

Although partly isolated from the rest of north Gondwana during the Ordovician, the Prague Basin shares faunas with Sardinia and Morocco, as all show the transition from Deanaspis to Onnia. Spain, Britain, and the Baltic also share some species with Bohemia, particularly in the high Caradoc and Ashgill (Bohdalec and Králův Dvůr Formations).

A literature-based compilation of phylogenetic relationships and biometric measurements of 342 Cenozoic planktonic foraminiferal species suggests that the group shows a net increase in size through the Cenozoic, thus appearing to follow Cope's Rule of phyletic size increase. However, when the data are corrected for size-related biases, they do not support the hypothesis that this apparent trend is driven by an organismal adaptive advantage of larger size.

When the planktonic foraminifera return to their “primitive” globigerine morphology during the Eocene-Oligocene transition, there is no indication of size-dependent origination or extinction; however, when the extinction signal is decomposed into pseudoextinctions and true lineage terminations, a differential pulse of pseudoextinction is observed among the smaller forms. This observation suggests that smaller bodied species, rather than surviving stressful times with static morphologies, may evolve their way through times of crisis and go on to found lineages which, by virtue of their initial small size, are stochastically likely to increase in mean size during subsequent diversification. Thus, one general explanation for Cope's Rule might be that smaller bodied species are more adaptively responsive due to their tendency to have shorter generation times. During times of stress, this adaptive responsiveness may give them an advantage that is correlated with, but causally unrelated to, their size.

Ten species of macruran, anomuran, and brachyuran decapod crustaceans, arrayed in eight families, were collected from seven localities in the Jagüel and Roca Formations, west-central Argentina. All of the decapods were collected from the Maastrichtian Jaqüel Formation and a part of the Roca Formation dated as Maastrichtian–Danian. All but one of the taxa, Xanthilites gerthi Glaessner, represent first occurrences in the unit and six had not been described previously from Argentina. Six taxa, Thaumastoplax rocaensis n. sp., Proterocarcinus lophos n. gen. and sp., Lobonotus lobulata n. sp., Glyphithyreus wichmanni n. sp., and Costacopluma australis n. sp. are new. Comparison of the fauna with Cretaceous and Paleogene faunas in Chile, Antarctica, and New Zealand indicates that the Argentinian fauna was strongly influenced by dispersal from lower latitude, Atlantic and Tethyan sources in marked contrast to the high latitude, Pacific affinities of the other faunas. There is no evidence that the Argentinian brachyuran fauna was seriously affected by the K–T extinction event. Seven of the genera from the Roca Formation are known from Cretaceous and Paleogene rocks.

A low-diversity assemblage of smaller calcareous microfossils is present in the Upper Mississippian Maxville Limestone in Muskingum and Perry Counties, southeastern Ohio. Diagnostic faunal elements that suggest an early Chesterian age include the foraminifers Neoarchaediscus maxvillensis n. sp., Paraarchaediscus aff. P. Pachytheca (Petryk), Paraarchaediscus cf. P. koktjubensis (Rauzer-Chernousova), Endothyra excellens (Zeller), Endothyra bowmani Phillips emend. Brady, and attached forms. The presence of these diagnostic faunal elements in the Chesterian of Ohio significantly extends their known geographic range into the eastern Midcontinent region.

Other forms present include the foraminifers Priscella? of the group P. prisca (Rauzer-Chernousova and Reitlinger), Diplosphaerina inaequalis (Derville), Earlandia spp., and the problematic Asphaltinoides macadami (Brenckle and Groves) and Salebra irregularis Bogush and Brenckle. Microfossils are present in both calcareous mudstone and limestone.

The Prairie Bluff Chalk of Alabama and Mississippi yields a diverse ammonite fauna of Maastrichtian age. Twenty-eight species, of which three are new, are recorded herein: Pseudophyllites indra (Forbes, 1846), Hauericeras rembda (Forbes, 1846), Pachydiscus (Pachydiscus) maconensis n. sp., P. (P.) cf. gollevillensis (d'Orbigny, 1850), P. (P.) jacquoti (Seunes, 1890), P. (P.) egertoni (Forbes, 1846), Sphenodiscus lobatus (Tuomey, 1854), S. pleurisepta (Conrad, 1857), Coahuilites sheltoni Böse, 1928, Nostoceras (Nostoceras) alternatum (Tuomey, 1854), N. (N.) mendryki Cobban, 1974a, N. (N.) magdadiae Lefeld and Uberna, 1991, N. (N.) irregulare n. sp., Glyptoxoceras torquatum (Morton, 1834), Glyptoxoceras sp. A, Glyptoxoceras? sp., Baculites lomaensis Anderson, 1958, Baculites spp. A–C, Eubaculites labyrinthicus (Morton, 1834), E. carinatus (Morton, 1834), Baculites? trabeatus (Morton, 1834), Trachybaculites columna (Morton, 1834), Discoscaphites conradi (Morton, 1834), D. gulosus (Morton, 1834), Jeletzkytes criptonodosus Riccardi, 1983, Trachyscaphites alabamensis n. sp., and T. yorkensis (Stephenson, 1941). One genus, Trachybaculites, is new. The bulk of the fauna can be referred to a Discoscaphites conradi assemblage zone, but some elements in the fauna are significantly older.

87Sr/86Sr chronostratigraphy is an important tool for dating and correlating vertebrate and invertebrate faunas preserved in marginal marine sequences. Freshwater flux in marginal marine environments can influence the 87Sr/86Sr of mollusks and, consequently, Sr-chronostratigraphic interpretations based upon them. To appraise the potential problem we have used a two-component mixing equation to evaluate levels of “measurable effects” (defined as ±5 × 10-5 departure from the marine 87Sr/86Sr ratio) in marginal marine environments. A measurable effect occurs at 12 parts per thousand salinity for a weighted world average river, but can occur at salinity > 34 ppt for rivers draining basins with ancient granitic rocks. Predictions were tested with analyses of mollusks from estuaries in the Mississippi Sound and coastal Florida. Analyses document the largely regular variation in 87Sr/86Sr predicted, but also show that a simple two-component model cannot account for all of the variation. Carbonates formed in restricted marine settings may not record a marine 87Sr/86Sr signal, emphasizing the need to consider freshwater flux for 87Sr/86Sr chronostratigraphy.

The thorax of Hypodicranotus has ten segments and a spine on the eighth. The ages of Erratencrinurus s.l. spicatus and Erratencrinurus (Erratencrinurus?) vigilans in the Lake St. John district do not confirm their temporal roles leading to subgenera of Erratencrinurus, as has been recently suggested. Phylogenetic analyses of large data sets of species previously referred to Encrinuroides and Physemataspis yield a minimal length cladogram containing 18 species. Encrinuroides is restricted to four species, two of which have biogeographic affinities with Iapetus. These results lead to three clades, named the Walencrinuroides n. gen. clade, Frencrinuroides n. gen. clade, and finally the Physemataspis clade, with an enlarged concept of the genus with the erection of Physemataspis (Prophysemataspis) n. subgen. These last three clades are restricted to North America and Scotland, with alternating predominance of one region. Walencrinuroides s.l. gelaisi n. gen. n. sp. is described. New morphological data on Erratencrinurus s.l. spicatus confirm its close relationship with the clades discussed above. Data are insufficient for phylogenetic analysis of selected cheirurine species here surveyed. Eye position, glabellar segmentation, and pygidial shape differentiate the genera Ceraurus and Gabriceraurus; emended diagnoses of these genera are presented. Ceraurus globulobatus and C. matranseris are distinct, but morphologically close to one another. The status of Gabriceraurus dentatus can be stabilized on its extant types.

We document and describe the trilobite faunas of the Lower Cambrian Shackleton Limestone. The faunas include taxa of Atdabanian, Botomian and possible Toyonian ages and have affinities with those known previously from Gondwana or peri-Gondwana terranes. The geographic distribution of these organisms reveals a large measure of faunal connectedness around the margin of this vast supercontinent in Early Cambrian time. This connectedness extended even to taxa that inhabited shallow-water carbonate shelf environments, because the Shackleton Limestone accumulated in a variety of shallow subtidal and peritidal settings along the ocean-facing margin of the East Antarctic craton, subsequent to a Neoproterozoic rifting event. Although the fossilized Shackleton Limestone fauna is dominated by archaeocyathans, trilobites are common locally. We describe the remains of 35 trilobite taxa from 32 collecting localities. One species, H. granulosa, is assigned to the new genus Holyoakia; the remaining new species are Pagetides (Discomesites) spinosus, Lemdadella antarcticae, Kingaspis (?) convexus, Yunnanocephalus longioccipitalis, and Onchocephalina (?) spinosa.

New collections, as well as original type material, of Lower and Middle Ordovician sponges from the Mingan Island Archipelago are described and figured from the Mingan and Romaine Formations. Archaeoscyphia minganensis (Billings, 1859), Hudsonospongia minganensis Raymond and Okulitch, 1940, H. irregularis Raymond and Okulitch, 1940, H. duplicata Raymond and Okulitch, 1940, Zittelella varians (Billings, 1861a), and Eospongia roemeri Billings, 1861, are redescribed from original type specimens and new collections. The species Archaeoscyphia pulchra (Bassler, 1927), Rhopalocoelia clarkii Raymond and Okulitch, 1940, Psarodictyum magnificum Raymond and Okulitch, 1940, and Lissocoelia ramosa Bassler, 1927 are reported and described from the Mingan Islands for the first time. To these sponges are added the new species Anthaspidella amplia, Archaeoscyphia undulata, Hudsonospongia nodosa, and Zittelella grossa, which are described from type specimens from the Mingan Formation.

The assemblage from 12 localities from the Mingan Formation, and one from the Romaine Formation, represents one of the most diverse demosponge faunas from eastern North America. Sponges in most of the localities accumulated as transported debris or lag gravels, but locally, some grew in small reefoidal mounds and also accumulated as adjacent debris.

The new species Cyathophycus pseudoreticulatus and a fragment of Cyathophycus reticulatus? Walcott, 1879, are described and reported from the lower part of the Upper Member of the Vinini Formation from black shale of late Whiterockian age. The sponges were collected from the north fork of Vinini Creek, in the north-central part of the Roberts Mountains, Eureka County, Nevada.

The discovery of a new locality yielding giant Guadalupian (Lower Permian) fusulinids in east-central Alaska extends the range of these forms much farther north than previously known, and into a tectonostratigraphic terrane from which they previously had not been reported. The number of areas from which giant parafusulinids are known in North America is thus raised to eight. Three of these localities are in rocks that previously had been referred to the allochthonous McCloud belt arc, and one, West Texas, is known to have been part of Paleozoic North America. Comparison of species from all areas suggests that there are two closely related species groups: one represented in Texas and Coahuila, and the other represented in Sonora, northern California, northeastern Washington, southern and northern British Columbia, Alaska, and apparently in Texas. These groups may differ because they are of slightly different ages or because interchange between the faunas of Texas–Coahuila area and the other regions was somewhat inhibited during the Early Permian.

A fauna of eight taxa of demosponges and hexactinellid sponges has been collected from the Lower Devonian (Lochkovian) Ross Formation, largely out of the upper Birdsong Shale Member in Benton, Decatur, and Perry Counties in west-central Tennessee. The Upper Birdsong Shale (“bryozoan zone”) in which the sponges are most common appears to have been deposited below normal wave base in a quiet marine environment, and represents a terrigenous clastic sediment influx onto a carbonate shelf that had existed in the area from at least the middle Silurian. Benton Quarry in Benton County was the most productive locality for fossil sponges.

The new demosponge genera and species Ginkgospongia foliata and Coniculospongia radiata occur with the new species Haplistion lobatum and skeletal mats of fine spicules, along with moderately rare specimens of Hindia sphaeroidalis Duncan. The new hexactinellid genus and species Stiodermiella amanita and Stiodermiella tetragona are characterized by peculiar ornamented papillose, swollen spicules that produce a massive, armored layer on the upper part of the sponge. The latter are associated with the new hexactinellid species Twenhofelella bulbulus, which has relatively normal-appearing hexactines, and with an indeterminate hexactinellid genus, which has spinose hexactines in irregular orientation in a small, platelike fragment. Root tufts of probable hexactine origin also occur.

Swollen spicules in Stiodermiella are reminiscent of swollen spicules in the family Stiodermatidae Finks, largely from the Permian of western Texas, but elements of the family are also known from Lower Carboniferous to Permian rocks in Europe and North America.

Integration of foraminiferal biostratigraphy, 87Sr/86Sr isotope stratigraphy, and traditional physical stratigraphy has provided a refined age control of a poorly known Oligocene-to-Pleistocene sedimentary sequence nonconformably covering the crystalline basement complex of the Calabrian microplate, a continental block which rifted off the southern margin of the European plate during Neogene time. In spite of the fossil-poor content of the sequence, the simultaneous use of paleontological and geochemical techniques have resulted in the following conclusions. 1) The age of an unnamed, thin calcarenite unit locally present at the base of the sequence, previously considered Rupelian to early Aquitanian in age, has been refined to Chattian (27.8–24.8 Ma). This calcarenite was considered a basal, conformable member of the overlying Stilo-Capo d'Orlando Formation. However, this study indicates that it is separated from the Stilo-Capo d'Orlando Formation either by an angular unconformity or by a disconformity representing a significant time interval. 2) The Stilo-Capo d'Orlando Formation has a latest Chattian–earliest Aquitanian to Burdigalian age. Previously published reports suggested deposition over a much longer time span, ranging from late Rupelian to Langhian. 3) An unnamed deep-marine siliciclastic unit mostly composed of conglomerate and sandstone and previously considered Tortonian in age is, in fact, Serravallian to Tortonian. 4) The depositional interval of the “trubi,” fine-grained marine deposits, has been independently confirmed to span the Pliocene-Pleistocene.

The results of this study provide a framework for future sequence–stratigraphic and paleotectonic studies in the area, and prove the effectiveness of an integrated paleontological and geochemical (87Sr/86Sr) approach in the study of fossil-poor sedimentary sequences.