Gnamptorhynchos, a rhynchonellid-like orthid brachiopod, evolved from Platystrophia in Maysvillian (early Ashgill) time, and survived both the end-Richmondian and end-Hirnantian episodes of the latest Ordovician mass extinction. The name of the type species of Gnamptorhynchos, G. inversum Jin, 1989, is rejected and replaced by Gnamptorhynchos globatum (Twenhofel, 1928), which is a senior synonym. Gnamptorhynchos manitobensis new species is described here from the Selkirk Member (Maysvillian) of the Red River Formation, southern Manitoba. The new species is characterized by a transversely extended, strongly biconvex to globular shell with prominent umbones, relatively numerous costae and a notothyrial cavity supported dorsally by a short median ridge. It constituted part of a Late Ordovician epicontinental fauna that once spread widely in shallow, equatorial seas of North America. The new species is a morphological intermediate between Platystrophia and Gnamptorhynchos, with Platystrophia-like interareas, hingeline, and cardinal process, but Gnamptorhynchos-like shell posterior and notothyrial platform. Previously, Gnamptorhynchos was known from Hirnantian to mid-Aeronian rocks. The new species extends the lower range of the genus to Maysvillian.

Tubes suspected to be those of vestimentiferan worms are abundant in carbonate boulders at one locality in the lower Oligocene part of the Lincoln Creek Formation along the Canyon River, Grays Harbor County, Washington. The largest tubes exhibit the same general orientation and are arranged in clusters. The tube walls are preserved as aragonite that is, in some cases, replaced by silica. The original tube walls either had a high carbonate content or were indurated very early by aragonite mineralization of the organic wall. The carbonate cements around, on, and inside of the tubes were precipitated due to the microbial oxidation of hydrocarbons at a cold-seep. After lithification, the carbonate fragmented as it slid or slumped, along with other sedimentary debris, downslope into deeper waters. This is one of the few reports of an ancient cold-seep chemosynthetic community dominated by tube worms, and the third report of an allochthonous cold-seep carbonate within a deep-water depositional setting.

Cambrian biotic zonation on the Siberian Platform reflects differentiation of the depositional environments (inner shelf, outer shelf and open basin). The combination of the chart of trilobite biofacies replacement and the curve of sea-level fluctuations shows that trilobite biofacies replacement occurs as a rule at times of sign reversal and distinct change in the rates of sea-level rise or fall. The boundaries of major Siberian platform Cambrian chronostratigraphic units, such a stages and series, frequently coincide with the boundaries of biofacies in stratigraphic succession related to sea-level fluctuations. If these fluctuations are gradual and restricted, then the boundaries of the Cambrian stages and series cannot be isochronous levels at a global scale. The known levels for intercontinental correlation on the Siberian Platform include boundaries of the adjacent Triplagnostus gibbus and Tomagnostus fissus Zones from the uppermost Amganian Stage (Middle Cambrian) and the Glyptagnostus stolidotus and Glyptagnostus reticulatus Zones of the lower Upper Cambrian. Both levels correspond to boundaries between highstands and lowstands on the Siberian Platform and appear to serve as boundaries of high rank. Evolution of the trilobite biofacies zonation is illustrated by genera typical for each of the various Cambrian paleogeographic environments on the Siberian Platform.

Although known previously from only two specimens from northern Greenland, new material from Marjuman boulders in debris flows of the Cow Head Group of western Newfoundland demonstrate that Verditerrina Robison is a menomoniid trilobite that is closely related to Hysteropleura Raymond. Following a parsimony analysis using the PAUP program, Verditerrina is used at the subgeneric level to label a distinctive monophyletic group within Hysteropleura. Three new species are established for the Newfoundland material: Hysteropleura (Verditerrina) adraini, H. (V.) edgecombei and H. (V.) ramskoldi. All three species undergo substantial modification of the anterior border of the cranidium during holaspid ontogeny. Two of the species, H. (V.) adraini and H. (V.) edgecombei, develop elongate, tongue-like borders that are reminiscent of those of calymenids such as Spathocalymene Tillman.

The trilobite genus Jujuyaspis Kobayashi, 1936, an index fossil of earliest Ordovician age, is recorded from the Yosimuraspis Zone of the Mungok Formation (Lower Ordovician) for the first time in Korea. The Yosimuraspis Zone comprises Yosimuraspis vulgaris Kobayashi, 1960; Jujuyaspis sinensis Zhou in Chen et al., 1980; Elkanaspis jilinensis Qian in Chen et al 1985; and pilekid genus and species indeterminate. Closely comparable faunas to the Yosimuraspis Zone are well represented in North China. The occurrence of Jujuyaspis allows the correlation of the Yosimuraspis Zone with the earliest Ordovician faunas of North America, South America, and Scandinavia, and suggests that the Cambrian-Ordovician boundary in Korea be placed at the base of the Yosimuraspis Zone.

Twenty-three species of trilobites are recognized in the lower Mississippian Caballero and Lake Valley Formations of southern New Mexico. Species exhibit a segregation into shelf and off-shelf faunas, and can be subdivided into three distinct stratigraphic faunas. Species found in the Caballero Formation are similar to those found in the Chouteau Formation of Missouri. A second fauna, comprising species found in the Alamogordo, Nunn, and Tierra Blanca Members of the Lake Valley Formation, is correlated with the Fern Glen and Burlington Formations of Missouri. The third fauna found in the Arcente and Dona Ana Members of the Lake Valley Formation is correlated with the Warsaw and Salem Formations of the United States midcontinent region.

Named species from the Kinderhookian Caballero Formation include: Dixiphopyge armata (Vogdes, 1891), Comptonaspis swallowi (Shumard, 1855), Brachymetopus indianwellsensis new species, Ameropiltonia perplexa new species, Griffithidella caballeroensis new species, and Kollarcephalus granatai new genus and new species. Named species from the Lake Valley Formation include: Pudoproetus fernglenensis (Weller, 1909), Breviphillipsia semiteretis Hessler, 1963, Griffithidella doris (Hall 1860), Phillibole planucauda (Brezinski, 1998), Piltonia carlakertisae new species, Australosutura llanoensis Brezinski, 1998, Thigriffides triangulatus new species, Thigriffides? alamogordoensis new species, Namuropyge newmexicoensis new species, Nunnaspis stitti new genus and new species, Hesslerides arcentensis new genus and new species, as well as an unnamed species of Proetides Hessler, 1962, Namuropyge Brezinski, 1988, and Thigriffides Hessler, 1965.

Small coprolite-bearing borings occur in the stem of the filicalean tree fern Itopsidema vancleaveii Daugherty from the Chinle Formation of Late Triassic Age (Carnian Stage) in Petrified Forest National Park, Arizona. These borings are restricted to parenchyma within the leaf petioles and among the adventitious roots of the root mantle. Although they are not lined by wound tissue, some of the borings in the leaf petioles contain small discontinuous masses of wound-tissue at a few places along some of the walls, indicating that the plant was alive when it was attacked. Coprolites within the borings generally are small (mostly about 40–50 μm in diameter and 85–100 μm in length) and oval in longitudinal section and round to weakly hexagonal in transverse section; they consist of very small particles of unidentifiable plant matter. Although the weakly hexagonal coprolites are similar to those produced by termites but they are an order of magnitude smaller. Furthermore, the borings are much smaller than those produced by known extant termites. It is likely that oribatid mites produced the coprolite-bearing borings and coprolites. This occurrence is significant because it bridges the Late Permian to Early Jurassic gap in the geologic record of endophagous mites and also contributes new data on arthropod activity during the Late Triassic in southwestern North America.

A new late Osagean (Lower Mississippian) crinoid fauna is described from the Muldraugh Member of the Borden Formation of central Kentucky. The Muldraugh Member records a mixed carbonate-siliciclastic tempestite-dominated ramp environment. This is the first report of late Osagean crinoids from this depositional setting on the eastern side of the Eastern Interior Basin of the midcontinental United States. The Muldraugh crinoid fauna contains 66 species and is dominated by advanced cladids. This fauna has similarities to other late Osagean faunas but is distinctive both in species abundance and rank order abundance of species. Eight new species are described from this fauna, including Camptocrinus nudus, Paradichocrinus ramus, Poteriocrinites horowitzi, Parascytalocrinus pentagonus, Abrotocrinus debrae, Abrotocrinus springeri, Worthenocrinus hardinensis, and Mespilocrinus myllos.

Leodia divinata new species is described from Early Pliocene deposits in Venezuela. It is only the second known species of Leodia, which was otherwise represented by a single extant and Late Pleistocene species, L. sexiesperforata. We also provide an overview of the characters that distinguish Leodia from other mellitid genera and that distinguish L. divinata from L. sexiesperforata. The evolutionary importance of L. divinata is discussed, along with its contribution to our knowledge of the phylogeny of the Mellitidae. It is now possible to partially fill a major and previously vexing gap in the stratigraphic record of the mellitids, and place in a phylogenetic context the strong preference of modern Leodia for biogenic, calcareous sand bottoms.

An unusually diverse fauna of biserial graptolites has been recovered from the Kajrak and Urubulak formations in the Kurama Range of eastern Uzbekistan. The fauna consists of 26 distinct taxa, 24 of which are systematically described and illustrated. The entire fauna can be assigned to the Akidograptus ascensus–Parakidograptus acuminatus Biozone, which is earliest Rhuddanian (early Llandovery) in age. Within this biozone, however, three regionally distinguishable subzones can be recognized, the N. lubricus, A. cuneatus and H. sinitzini subzones. New taxa described are Normalograptus larini, Normalograptus skeliphrus, “Paraclimacograptus” kiliani kuramaensis, “Glyptograptus” jerini, and “Glyptograptus” ugurensis. New combinations described are Normalograptus acceptus (Koren’ and Mikhaylova, 1980), Normalograptus bicaudatus (Chen and Lin, 1978), Normalograptus jideliensis (Koren’ and Mikhaylova, 1980), Normalograptus lubricus (Chen and Lin, 1978), Normalograptus mirnyensis (Obut and Sobolevskaya, 1967), and Sudburigraptus illustris (Koren’ and Mikhaylova, 1980).

Populations of the widely distributed Early Ordovician conodont Paracordylodus gracilis Lindström, 1955, have been measured and studied in detail. Natural clusters and rich collections of isolated elements allowed calculations of size frequency distributions and construction of survivorship curves. Small morphological differences, as well as dissimilarities in population structure between collections from separate areas, were observed. This led to the recognition of Type A populations from Kazakhstan and other Arenigian warm water, low latitude regions and Type B populations from Baltica and other areas with cool water, mainly located at high latitudes in the Arenigian.

A collection of 57,877 conodont elements that includes 39 species representing 30 genera was made from the upper part of the Phragmodus undatus Zone and the lower part of the Plectodina tenuis Zone (late Turinian–early Chatfieldian). Conodont samples were collected from 30 sections in eastern North America and Baltoscandia, where the P. undatus–P. tenuis Zone boundary projects into B. alobatus Subzone based on K-bentonite bed correlation. Elements previously assigned to form-species of Oistodus are shown to be apparatus associates in coniform apparatuses of Besselodus. Pseudobelodina manitoulinensis new species is described and the apparatus-based taxonomy of Scyphiodus primus and Staufferella polonica are proposed.

Conodonts representing 38 species of 26 genera have been identified in samples from Upper Ordovician rocks at three central Nevada localities. Ranges of these species and associated graptolites are used graphically to determine correlation of the strata considered with an evolving composite standard that includes information from Ordovician strata at more than 100 localities in North America. Results indicate that the Hanson Creek Formation at Lone Mountain is latest Edenian through mid-Richmondian in age; that the Ordovician part of the Hanson Creek in the Monitor Range section spans an interval from Maysvillian through Richmondian; and that the upper 29 m of the Vinini Formation at the Vinini Creek locality is of mid-Maysvillian to late Richmondian age. Physical discontinuities in the Ordovician-Silurian boundary interval complicate correlations, but it is now clear that conodonts that range upward into, and have long been considered distinctive of the Lower Silurian, make their debut in central Nevada in an upper segment of the Upper Ordovician Normalograptus persculptus graptolite zone that may be latest Richmondian in age.

Abderitid marsupials are common in vertebrate-bearing deposits from the middle Miocene of Argentine Patagonia. Recent collections from the inland Pinturas Formation and slightly younger coastal Santa Cruz Formation have dramatically increased the number of abderitid specimens. These new collections permit a re-assessment of abderitid taxonomy as well as an investigation of the dietary habits of these unique small mammals. The vast majority of new specimens represent Abderites meridionalis; Pithiculites minimus is rare. Patterns of macrowear on the double-bladed, plagiaulacoid shearing complex suggest that abderitids used these teeth to prepare a variety of resistant food items as do modern marsupials with double-bladed shearing systems. Data summarizing molar-shearing morphology and body size further suggest that A. meridionalis was a frugivore. The diet of the small P. minimus is equivocal, although it may represent a mixed feeder (frugivore/faunivore). A comparison of relative species richness and dietary adaptation between abderitids and palaeothentids (a closely related caenolestoid family that lacks the highly specialized shearing complex of abderitids) reveals distinct evolutionary patterns within the two lineages. Abderitids exhibit low species diversity. In contrast, palaeothentids are represented by 17 species, lack highly specialized shearing mechanisms, and typically exhibit molar morphologies that range from frugivory to faunivory and include mixed feeders. Both temporal and geographic variation are introduced as possible factors affecting differences in the relative abundance of abderitids and palaeothentids in the Pinturas and Santa Cruz Formations.

A small collection of carnivoran fossils from the South Turkwel hominid site is described. The fauna is composed of Megantereon ekidoit new species, Homotherium sp., Crocuta cf. dietrichi, cf. Pachycrocuta sp., Canis new species A., cf. Civettictis sp., Viverridae or Herpestidae indet., and Lutrinae indet. The record of Megantereon and Canis, as well as Pachycrocuta and Civettictis, if these genera are identified correctly, represents the earliest occurrences of their respective taxa in Africa. These specimens suggest a relatively rapid reorganization of the carnivore guild some time around 3.5 Ma, followed by a longer period of transition to a fauna more comparable in composition to the modern one.

Sun and Boucot (1999) described the ontogenetic development of several important morphologic structures in Stringocephalus gubiensis, which occurs in the late Eifelian kockelianus Zone of South China. They found that in small specimens ranging from 5 to 18 mm in width the cardinal process forms a pair of discrete, rodlike lobes (Sun and Boucot, 1999, Figs. 1.1–1.6, 2.1–2.6). In specimens generally exceeding 20 mm in width, these lobes fuse to form the single, long, terminally bifid, stalklike cardinal process characteristic of Stringocephalus.

This finding of Pseudomulceodens in Mississippian-age rocks of the Santiago Formation provides the first evidence of the molluscan class Rostroconchia in Mexico. Elsewhere in North American Mississippian rocks the class occurs in Arkansas (Hoare et al., 1982, 1988); Illinois (Weller, 1916); Indiana (Beede, 1906); Iowa (White and Whitfield, 1862); Michigan (Winchell, 1870); Montana and Nevada (Pojeta and Runnegar, 1976); Ohio (Hyde, 1953; Hoare, 1990); and Oklahoma (Branson, 1958).

In a series of papers on Paleozoic stratigraphy and paleontology in southern Mexico, Buitrón and colleagues (Buitrón, 1977; Velasco De León and Buitrón, 1992; Buitrón et al., 1987; Villaseñor et al., 1987; and Esquivel-Macías, 1996) utilized the crinoid pluricolumnal taxonomy of Moore and Jeffords (1968) to help establish a Pennsylvanian age for the lower Santa Rosa Formation, the del Monte Formation, and the upper Patlanoaya Formation. Since 1968, crinoid pluricolumnal taxonomy and the biostratigraphic utility of pluricolumnals has received very little attention in North America. Whereas the biological classification of crinoids is vested primarily in attributes of the crown, these papers illustrated the biostratigraphic utility of crinoid columnals and pluricolumnals where crinoid crowns are not recovered. Indeed, this was the intent of R. C. Moore, when he embarked on his studies of columnals and pluricolumnals (Moore et al., 1968; Moore and Jeffords, 1968; and Jeffords and Miller, 1968).

Although pareiasaurs are one of the most abundant and conspicuous elements of Late Permian terrestrial ecosystems, small individuals of these reptiles (either small species or juveniles of large species) are extremely rare. Until now, the smallest known pareiasaur is the type of the late, heavily armored form Anthodon (=Nanoparia) pricei (Bernard Price Institute of Palaeontological Research, Johannesburg 1/6), with a skull length of 10 cm and an inferred snout-vent length of approximately 50 cm. This is presumably an adult of a dwarf form, since all elements of the skull and postcranial skeleton are fully ossified, sutures are closed, and the dermal armor is more highly developed than in any other pareiasaur (Broom and Robinson, 1948; Brink, 1955; Findlay, 1970; Lee, 1997). A second and as yet undescribed specimen (Geological Survey, Pretoria CM86/544) is approximately the same size, being only very slightly larger (Lee, 1997). No other specimens of this taxon are known. An unnumbered humerus in the Amalitsky collection of the Palaeontological Institute, Moscow, is from a pareiasaur of similar size to the second specimen of A. pricei. However, this specimen is presumably a juvenile of a large form: the ends of the humerus are unossified, and the specimen comes from the North Dvina bone beds, which have yielded numerous specimens of the large pareiasaur Scutosaurus but no other pareiasaur taxon. Here, we re-evaluate a specimen originally described as a dicynodont tail, and later as a procolophonoid, and demonstrate that it is actually a juvenile of the pareiasaur Elginia mirabilis. It is also by far the smallest pareiasaur so far known, being approximately half the dimensions of the next smallest individual, the type specimen of Anthodon pricei. The newly recognized specimen provides new information on the ontogeny of pareiasaurs and the homology of some problematic skull elements.