Three microfossil assemblages occur in the Mesoproterozoic Bangemall Group (1625-1000 Ma) of northwestern Australia, each occupying a different environmental and taphonomic setting. In peritidal environments, benthic prokaryotic filaments and spheroids of matting habit and small size were permineralized by early diagenetic silicification of stromatolitic carbonates. In shallow subtidal environments, benthic filaments of large size and nonmatting habit and planktonic sphaeromorph acritarchs with thin walls and moderate dimensions were compressed in mildly kerogenous shale. In deeper subtidal environments, planktonic megasphaeromorph acritarchs with thick walls were initially entombed in concretionary nodules in highly kerogenous shale and then permineralized by silica during later diagenesis. Taxonomic diversity and numerical abundance evidently decrease offshore. The three assemblages have typical Mesoproterozoic aspects: peritidal benthic habitats were dominated by Siphonophycus-Sphaerophycus-Eosynechococcus-Myxococcoides-Palaeopleurocapsa, shallow subtidal settings were occupied by Siphonophycus-Leiosphaeridia-Pterospermopsimorpha-Satka, and offshore plankton consisted solely of very large chuarid acritarchs. Because of its taphonomic restriction to mid-intertidal stromatolites, the peritidal assemblage can be equated in microenvironment with a similar assemblage in the Neoproterozoic Draken Conglomerate, suggesting that ecological stasis at the community level can last for intervals up to 900 million years. In the deeper subtidal assemblage, the common chuarid has an unusual mode of preservation, in three dimensions in early diagenetic concretions, revealing that it possesses a thick multilamellate wall. Because of this distinctive ultrastructure, the new genus Crassicorium is erected for these fossils, which are among the oldest indubitable eukaryotes. Very large (34-55 μm in diameter) filaments from shallow subtidal habitats are assigned to the emended species Siphonophycus punctatum.

Moderately well-preserved Middle Triassic radiolarians were recovered from bedded limestone exposed at about 3 km west of Kefamenanu, West Timor, Indonesia. This limestone probably from the Aitutu Formation is considered to be an allochthonous block and is embedded in the Neogene Bobonaro Complex. The radiolarian fauna in this limestone is characterized by abundant radiolarians of typical Tethyan forms and is identical to that of the early Fassanian (early Ladinian) of European Tethys and other related faunas reported from the Philippines, Russian Far East, and Japan. The Aitutu Formation is thought to be deposited in an ocean environment dominated by a warm-water current system originating from the low latitude Tethyan realm. Fifty-nine species belonging to 34 genera, including five unidentified genera, are systematically treated, among them, five new species; Parentactinia suparkai, Pseudostylosphaera timorensis, Cryptostephanidium? megaspinosum, Tetrarchiplagia compacta, and Planospinocyrtis kefaensis.

Massive Upper Triassic (Norian) reef limestone at Eaglenest Mountain, Takla Group, British Columbia, contains a wide variety of shallow-water fossils in two different carbonate units. A sponge-coral facies contains the sponges Fanthalamia astoma (Seilacher, 1962), Fanthalamia multicanalis new species, Cinnabaria expansa (Seilacher, 1962), and Cinnabaria? sp. Cinnabaria expansa is a widely distributed North American terrane species which, along with F. astoma, was previously known from the Luning Formation of Nevada. Also included is the “disjectoporoid,” Pamiropora sonorensis Stanley, 1994, and a massive spongiomorph, Spongiomorpha tenuis Smith, 1927, previously endemic to the Eastern Klamath terrane of California. Colonial corals include: Retiophyllia quesneliana new species, Chondrocoenia waltheri (Frech, 1890), Crassistella cf. juvavica (Frech, 1890), Distichomeandra cf. austriaca (Frech, 1890), and Alpinophyllia flexuosa Roniewicz, 1989. A limestone conglomerate overlying these beds is dominated almost exclusively by the planktonic hydrozoan, Heterastridium conglobatum Reuss, 1865. A problematic taxon Lovcenipora cf. chaetetiformis Vinassa de Regny, 1915, is reported for the first time outside Timor and the Tethys. The faunas provide a first glimpse into the reef biota of the Quesnel terrane. They contain taxa previously known from the distant Tethys but also include endemics from other inboard terranes.

Delicate symmetrical structures in living chambers of autozooecia of some lower Paleozoic species of the order Trepostomata have been interpreted as indications of polypides with little further elaboration. Applications of the anatomy, mode of skeletal growth, and functional requirements basic to living species permit recognition of a few organs of these partially preserved polypides, their functions, and their relationships to enclosing skeletons. Only one basic polypide anatomy is indicated in lower Paleozoic trepostome species, in contrast to the wide diversity of polypide anatomy and their lack of correlation with skeletal characteristics in living stenolaemates. In general, the longer the evolutionary history, the greater the diversity of skeletal morphology in stenolaemates. Apparently, polypide diversity and lack of correlation with skeletal morphology also have increased over time.

The complex skeletal septa in autozooecial apertures of the lower Paleozoic trepostome Hallopora have been interpreted as reflecting an organ of full-sized feeding polypides. Applications of the basic biological concepts of living species suggest that the septa provided reduced skeletal apertures to fit smaller polypides of polymorphs that secondarily occupied the living chambers of full-sized degenerated feeding polypides.

Very few Jurassic bryozoan faunas are known outside Europe. Here we describe seven species of calcareous cyclostome bryozoans and one bioimmured soft-bodied ctenostome bryozoan (Simplicidium sp.) from the Middle Jurassic (?Bathonian) Carmel Formation of Utah. Three of the cyclostomes are placed in open nomenclature due to inadequate preservation and/or the lack of key reproductive polymorphs. A new genus, Patulopora, is established for Diastopora cutleri Cuffey and Ehleiter, 1984, following the discovery of gonozooids that place this species in the Multisparsidae rather than in the Plagioeciidae. Another of Cuffey and Ehleiter's (1984) species—Berenicea duofluvina—is reassigned to Microeciella on the basis of the gonozooids, and a similar but distinctly smaller form is described as M. pollostos new species. A second new species—Hyporosopora nielsoni—is a rare colonist of hardground undersurfaces. The Carmel bryozoan fauna is compared with better-known faunas from the northern European Middle Jurassic. Species richness and colony-form diversity fall well within the expected values for bryozoan faunas of this age, and endemism is detectable only at relatively low taxonomic levels. Evolutionary patterns based on studies of contemperaneous European bryozoan faunas during this time of cyclostome evolutionary radiation are reinforced by the palaeogeographically distant Carmel bryozoan fauna.

A silicified brachiopod assemblage living between the first and second episodes of latest Ordovician mass extinction is first described from micritic bioclastic limestone of Kuanyinchiao Bed, northwestern Guizhou, southwest China. It contains six species, Dalmanella testudinaria (Dalman, 1828), Plectothyrella crassicosta (Dalman, 1828), Hindella crassa incipiens (Williams, 1951), Eostropheodonta sp., the characteristic constituents of the Hirnantia fauna, and two new species, Fardenia modica and Dorytreta longicrura. It lacks Hirnantia, Kinnella, Cliftonia, and Paromalomena, the other characteristic elements of the Hirnantia fauna. A new, low diversity community (inner BA3) dominated by brachiopods is proposed as the Dalmanella testudinaria-Dorytreta longicrura Community along with the trilobite Dalmanitina nanchengensis Lu, rugose corals, and gastropods. Composition of this community of the Hirnantia fauna was controlled primarily by temperature, water depth, and substrate. Comparison with other communities of the Hirnantia fauna in south China supports this conclusion. Fluctuations in generic composition of the Hirnantia fauna and the related factors are also discussed.

Twelve brachiopod taxa are described from the Early Devonian (probable early Emsian) Pa Samed Formation of southern Thailand, including the new genus and species Quasiprosserella samedensis (Ambocoeliidae?) and the new species Plectodonta forteyi, Caplinoplia thailandensis, and Clorinda wongwanichi. They are the first undoubted Devonian brachiopods from Thailand. They represent the deeper-water Benthic Assemblages BA4-5, and, although clearly indicative of the Old World Realm, cannot be assigned to a particular biogeographical region. A new undescribed fauna from the contemporary Zebingyi Formation of Burma (Myanmar) is also noted.

A growth series of Stringocephalus gubiensis, described here, reveals that the cardinal process of Stringocephalus originated from a bilobate structure, and the growth of its dorsal median septum is highly related to cardinal process development. From this observation we conclude that Kaplex is, structurally and temporally, a suitable ancestor for Stringocephalus, with Bornhardtina ancestral to Kaplex. Subfamilial classification of the family Stringocephalidae is revised based on the presence or absence of median septa and the nature of hinge plates as well as on cardinal process formation. The Kaplexinae and Omoloninae are proposed as new subfamilies, with the Kaplexinae, including Kaplex and Erectocephalus, and the Omoloninae, including Omolonia, Kumbella, and Hemistringocephalus. Morphologic study of South China and Western Canadian Stringocephalus reveals that late forms of the genus tend to have a higher dorsal septum and more complex cardinal process than the early forms. In view of functional morphology, these trends reflect functional perfection of the cardinal process build-up and the lever system for improving the efficiency of opening and closing the shell.

Compared to their Recent counterparts, fossil abalone are rare and poorly known. Their taxonomy is problematic, because most of the 35 fossil species have been described from single specimens and shell characteristics of Recent species are extremely plastic. Thus, the use of fossil species in phylogeny is questionable. Abalone first appear in the Upper Cretaceous (Maastrichian) with one species each in California and the Caribbean, are unknown in the Paleocene, and appear again in the late Eocene and Oligocene of New Zealand and Europe. They are regularly found from the late Miocene to the Recent in tropical to temperate regions worldwide. Most records are from intensely studied areas: SW North America, Caribbean, Europe, South Africa, Japan, and Australia. Despite their highest present-day diversity being found in the Indo-Pacific, their scarcity in the fossil record in this region is remarkable. The family may have originated in the central Indo-Pacific, Pacific Rim, or Tethys. An extensive list of all known fossil records including new ones from Europe and western North America is given. Fossil and Recent abalone both apparently lived in the shallow, rocky sublittoral in tropical and temperate climates. No on-shore/off-shore pattern is detected.

Four specimens of a new cornute-grade stylophoran Ponticulocarpus robisoni new genus and species are described from the Spence Shale of northern Utah. Ponticulocarpus has wide and thin spinal and glossal processes interpreted as a mechanism for snowshoeing in a soft substrate. The presence of a posterior bar across the inferior posterior lobe, and two small bridges connecting the left adoral to M′2 on the superior face and connecting M1 to M3 on the inferior face are unique in cornute-grade stylophorans. The posterior bar may be homologous with the posterior marginals M′5 and M6 of other cornute-grade stylophorans, and an opening of the most posterior portion of the theca may have resulted in the development of the digital and glossal processes from marginals.

The Prout Dolomite of north-central Ohio lies disconformably above the lowest Givetian (upper Middle Devonian) Plum Brook Shale and below the lowest Famennian (upper Upper Devonian) Ohio Shale. A sample from its base yielded over 4,000 diverse conodont specimens. Included is Polygnathus ansatus Ziegler and Klapper, 1976, the index species for the Middle varcus Subzone, which is not reported from strata of this age in Ontario and Indiana, a fact that long caused their miscorrelation with the Lower varcus Subzone. Also present is P. rhenanus Klapper, Philip, and Jackson, 1970, considered to be also indicative of the Middle varcus Subzone in North America, and P. ovatinodosus Ziegler and Klapper, 1976. Lowest occurrences of the latter are in the middle part of this subzone; its presence indicates correlation with the lower Tully Limestone of New York, the basal unit of the Taghanic Series. The Prout and equivalent strata in the region therefore represent a long unrecognized continuous time-rock unit created by Johnson's (1970) Taghanic onlap. The collection includes a new species of Ancyrolepis, A. huntleyi; a new species of Polygnathus is left in open nomenclature, as are nine specimens assigned to Tortodus but of otherwise uncertain taxonomic status.

Givetian conodont correlation between North America and the Global Stratotype Section and Point established by the Subcommission on Devonian Stratigraphy (SDS) in Morocco is extremely problematical because of relatively erratic distribution (probably owing to limited ecologic adaptability) of P. ansatus and P. hemiansatus Bultynck, considered herein to be an early morphotype of P. ansatus. The base of the Givetian Stage has been defined by the SDS as coinciding with the lowest occurrence of P. hemiansatus. The only possible evidence for the SDS's hemiansatus Zone in North America involves reported occurrence of that morphotype in the uppermost Arkona Shale of Ontario, a position above the top of the Plum Brook Shale, which has been considered to be of Givetian age for decades. Also it appears that the interval between the Eifelian (lower Middle Devonian) kockelianus Zone and the hemiansatus Zone at the SDS's global-stratotype section in Morocco is of questionable age and probably too thin to represent continuous sedimentation. Adoption of a widely recognized faunal break at the base of strata deposited during the If T-R cycle of North America and Europe as the base of the Givetian could provide a sound alternative.

The oldest known microsaur is preserved in a nodule from the Kinkaid Formation (Mississippian; Elvirian) collected near Goreville, Illinois. At least eight individuals are represented: three by partial skulls plus vertebral column segments with associated limb elements, and five by postcrania only. Skulls are crushed, incomplete, and exposed mainly in palatal view. Palatal bones are denticulate and the palatine has in addition a single large tooth. The basipterygoid process is laterally directed and the basipterygoid joint is open. The atlas carries large articulating facets for proatlantes, a pair of which are identifiable in one specimen. These features have not been found previously in a microsaur. All vertebral segments are dominated by a biconcave pleurocentrum; sutures between the pleurocentrum and neural arch are visible in presacral vertebrae. Distinctive microsaurian intercentra occur between all presacral pleurocentra. Their presence reinforces the hypothesis that microsaur intercentra are homologous with those of other early tetrapods. Caudal vertebrae retain separate haemal arches and some have ribs.

Observed microsaur synapomorphies include: atlas with large median odontoid; atlas with concave lateral facets for occipital condyle; paired occipital condyles that are broad and concave; and thin, straplike intercentra. No observed features support a sister-group relationship with any other microsaur species, or placement within any higher level microsaur group. Because significant portions of the skeleton are missing or inaccessible, the Goreville microsaur is not formally named. A standardized, hierarchical format for skeletal characters is introduced that facilitates data sharing and comparison and fosters rapid archiving and retrieval.

Mixosaurus, a Middle Triassic ichthyopterygian, has traditionally been recognized as a typically primitive ichthyopterygian, but this view was recently questioned. Examination of the skull of Mixosaurus revealed many features to confirm this doubt. Its cranial characters, such as the parietal ridge and short supratemporal process of the parietal, are shared with derived ichthyopterygians from the Jurassic. Mixosaurus also has features that are derived within the Ichthyopterygia and unique to the genus, such as a long sagittal crest reaching the nasal, and an expanded anterior terrace of the upper temporal fenestra that also reaches the nasal. Phalarodon, Contectopalatus, and Sangiorgiosaurus are all considered as junior synonyms of Mixosaurus. The supratemporal, squamosal, and quadratojugal are all present in Mixosaurus atavus, as in basal ichthyopterygians. Because all basal ichthyopterygians, and even some derived ichthyopterygians from the Jurassic, have these three elements, the absence of the squamosal in Ichthyosaurus and Platypterygius should be considered derived if it is not preservational.

The largest documented cimolestid, Alveugena carbonensis new genus and species, is both morphologically and temporally intermediate between small, early cimolestids (such as Procerberus and Cimolestes) and the earliest documented conoryctid taeniodont Onychodectes tisonensis; this represents a transition between the suborders Didelphodonta and Taeniodonta. Diagnosis and description of A. carbonensis is based upon a partial skull and two isolated upper molars recovered from fluvial sandstones at UW locality V-91005, in upper parts of the Ferris Formation, western Hanna Basin, Wyoming. An earliest middle Puercan age for UW locality V-91005 is based upon: presence of taxa that are morphologically intermediate between characteristic early and middle Puercan species; presence of a species of Ectoconus morphologically more primitive than Ectoconus ditrigonus; and co-occurrence of taxa characteristic of Pu1 and Pu2 stratigraphically below and above it. Morphologic trends in evolution of the upper dentition of cimolestids reflect a relative broadening of the crown. A trend toward increasing body size amongst Puercan cimolestids appears to have coincided with a change from a carnivorous (or perhaps insectivorous) to an omnivorous diet, suggested by increased grinding function of the cheek teeth. Cladistic analyses support A. carbonensis as the sister group to O. tisonensis. No known autapomorphies preclude A. carbonensis from having been a plausible ancestor to O. tisonensis.

A new genus of mylagaluid rodent from the Miocene of the Great Basin, Hesperogaulus, is described, and to it two new species, H. gazini and H. wilsoni (type species) are referred. This genus differs from all other genera of later Tertiary mylagaulines in having: large bosses of rugose bone on the anterior end of the nasal bones; lower slope of the occipital bone; and unique separation of the anterior branches of the forked parafossette on the upper premolar.

Hepserogaulus n. gen. represents a distinct lineage of mylagaulids that has been separate from other members of the family since the early Barstovian. This genus is geographically limited to the Great Basin. Other later Tertiary genera of mylagaulids show geographic limitations to other parts of the continent as well.

One new calcareous nannofossil genus Senilatus; four new calcareous nannofossil species Calculites favosus, Lithraphidites? charactozorro Self-Trail and Pospichal, Rucinolithus oriens, and Watznaueria bybelliae; and one new combination, Senilatus zipperum n. gen. and comb., are described from Upper Cretaceous (upper Campanian to Maastrichtian) sediments of east-central South Carolina. These new species were described from five coreholes located in marine coastal plain deposits. There is evidence that the presence of one species, Senilatus zipperum, is indicative of nearshore, restricted environments. Scanning electron and light microscope pictures are provided for two species, Cretarhabdus multicavus Bukry, 1969 and Retemediaformis teneraretis Varol, 1991, that have previously been documented only with the transmission electron microscope. The ranges of these two species have been extended beyond those stated in the original descriptions.

When extracting or cleaning phosphatic fossils using acetic acid, the solutions must be buffered with calcium acetate to a pH greater than 3.6 for conodont and many fish taxa, and to a slightly greater pH for some conulariid, shark, and some fish taxa. Diagrams of the changes in pH and density during dissolution, rate of dissolution, and productivity per liter of acid provide a means for selecting the economically optimal process, monitoring the progress, and adjusting the composition of the solution when necessary.

More than 70 species of Paleozoic articulate brachiopods with color patterns have been reported in the literature (see Blodgett et al., 1983, table 1; Table 1). The majority of them are Devonian terebratuloid brachiopods. Twenty-two Permian brachiopod species were previously described as retaining color patterns. Most of them belong to Dielasma and have radial to subradial color patterns. Here we report a smooth spiriferid, Martinia? sp., with well-preserved radial color bands from Late Permian rocks of South China.

Tripp et al. (1977, p. 862) briefly described a small encrinurine from the Silurian of Wisconsin and Illinois. They refrained from naming this taxon, due to its being “as yet imperfectly known,” referring to the lack of testiferous material, the distortion and abrasion of most of the specimens, and the paucity of known cephalic sclerites. Lateral compression and abrasion of the only known cranidium (Tripp et al., 1997, pl. 114, figs. 8 and 9, from Brookfield, Wisconsin) were severe, but large, sparse tubercles were discernible. Gass et al. (1992) established Mackenziurus lauriae to include this and other material, all from various inter-reef Wenlock-Ludlow Racine Dolomite and Sugar Run Dolomite localities in Wisconsin and Illinois, respectively. All of this material is in the form of internal and external molds in dolomitized calcilutite, and most of the Wisconsin specimens are distorted to varying degrees. Among the material which Gass et al. (1992) introduced was a nonabraded, slightly-distorted cranidium with articulated librigenae (Gass et al., 1992, fig. 5.1-5.3) from the same locality in Wauwatosa, Wisconsin, which produced the majority of the other known material, and a complete, enrolled, nondistorted but weathered exoskeleton (Gass et al., 1992, fig. 5.4-5.7) from an unrecorded locality and formation in Grafton, Illinois. Those are only the second and third specimens known to preserve the cranidium. Differences in the rostral plate [inferred to be narrower (tr.) on the Wauwatosa specimen] and glabellar tuberculation (larger and fewer in number on the Grafton and Brookfield specimens) were attributed to intra-specific variation. Due to its superior preservation in contrast to the other cranidiumbearing specimens, and the more complete occurrence data, the Wauwatosa specimen was designated as holotype of Mackenziurus lauriae.