Well-preserved Ordovician conodonts are described from a micritic limestone sequence exposed in the Satun area of southern peninsular Thailand. the faunas represented by these conodonts have North Atlantic Realm affinities and are identical to those reported from North Atlantic Middle to Upper Ordovician successions. Representative conodonts of some of these faunas have also been reported from South China. in ascending order, three conodont zones are discriminated in the Satun sequence: the Pygodus anserinus range Zone, the Baltoniodus sp. cf. B. variabilis range Zone, and the Hamarodus europaeus range Zone. Strata between the B. sp. cf. B. variabilis and H. europaeus zones are not zoned. the conodont-bearing limestone is thought to have been deposited on the continental margin of northeastern Gondwana. Sixteen species belonging to 12 conodont genera, and two unidentified coniform elements, are systematically investigated.

Seventeen species of decapod crustaceans have been described from Campanian through Paleocene rocks in the Santa Marta, López de Bertodano, and Sobral Formations of the James Ross Basin, Antarctica. Of these, nine are new species: Metanephrops rossensis, Glyphea australensis, Paguristes santamartaensis, Munidopsis foersteri, Retrorsichela laevis, Plagiophthalmous collinsi, Rhinopoupinia bicornis, Cristafrons praescientis, and Torynomma (Torynomma) australis. One new family, Retrorsichelidae, and three new genera, Retrorsichela, Rhinopoupinia, and Cristafrons, were also named. This assemblage includes the first notice of brachyurans from the Cretaceous of Antarctica; six species are described. The nephropid lobster Hoploparia stokesi (Weller), the most common decapod throughout the section, exhibits significant morphological change throughout its range from late Santonian or earliest Campanian to Paleocene; however, variation of key features is asynchronous. The raninid brachyuran, Cristafrons praescientis, is second in abundance to H. stokesi. The occurrence of Metanephrops rossensis and Munidopsis foersteri represents the oldest geological records for these genera and the recognition of species of Paguristes, Plagiophthalmous, Torynomma, and Necrocarcinus constitutes the first notice of these genera in Antarctica. Of those taxa that have living congenors, the species of Metanephrops, Linuparus, and Munidopsis occupied habitats at inner shelf depths in the Cretaceous whereas their extant descendants are restricted to outer shelf and bathyal depths. This diverse decapod fauna is dominated by genera that range into the Cenozoic and appears to be a pioneer assemblage.

Kennardiids, members of a family of organisms that bore phosphatic sclerites, are present in Antarctica; previously, they had been found only in Australia. This new occurrence reinforces the concept of a faunal province shared between the continents during Early Cambrian time. Although the two known genera of kennardiids, Dailyatia Bischoff and Kennardia Laurie occur in Antarctica and Australia, no species are common to both continents.

Dailyatia is interpreted as having had tightly fitting sclerites that armored a bilaterally symmetrical, bipolar body; two alternative reconstructions are presented. Taxa include two new species, Dailyatia braddocki and Dailyatia odyssei, and two unnamed species of Kennardia.

A new specimen of the Cretaceous trionychoid turtle Basilemys praeclara Hay, from the Frenchman Formation (Upper Maastrichtian) of Saskatchewan, confirms the validity of the species, previously known only from the type specimen. Basilemys praeclara is considered the sister taxon of Basilemys sinuosa, and the restriction of this clade to the late Maastrichtian reinforces the distinctiveness of the Lancian chelonian fauna from the older Judithian chelonian fauna. Basilemys, Nanhsiungchelys, and Zangerlia comprise the family Nanhsiungchelyidae, with Basilemys and Nanhsiungchelys being sister taxa within the family.

An abundant conodont fauna was recovered from 202 samples taken from the Becscie, Merrimack, and Gun River formations of early Llandovery (Early Silurian) age on Anticosti Island, Québec. From the collection of 22,409 identifiable specimens, 28 species and four associations representing 12 genera and one group of drepanodontiform elements are documented and their stratigraphic ranges established. One new genus, Rexroadus, is established for two species earlier assigned with question to Oulodus. New species described are Icriodella dicrana, Oulodus sigmoideus, Ozarkodina strena, and Pterospathodus? originalis. The fauna is dominated by species of Ozarkodina and Oulodus; many species have a first appearance that is slightly older than elsewhere suggesting that the Anticosti Basin may have been an important evolutionary radiative center in the early Silurian. There is a slow and progressive diversity increase in conodonts through this interval after the initial appearance of many new taxa in the basal Silurian following the mass extinction in the terminal Ordovician. The Anticosti Llandovery sequence represents one of the few highly fossiliferous, continuous successions in the world and a new conodont biozonation based on conodonts for the Llandovery is proposed with the following interval zones in ascending order: Ozarkodina hassi (new), Ozarkodina strena (new) [subdivided into Oulodus jeannae (new) and Oulodus panuarensis (new) subzones], Ozarkodina clavula (new), Ozarkodina aldridgei (new), Pterospathodus celloni, and Pterospathodus amorphognathoides zones.

Collection of over a dozen specimens of Hyolithes aclis Hall from the Middle Devonian of New York indicates that this species belongs to a new genus, Hallotheca, to which the species Hyolithes halli (Hall) is also assigned. However, the generic assignments of the Silurian species Hyolithes cliftonensis Foerste and the Devonian species H. centennialis Barrett, H. ceratophilus Clarke, H. neapolis Clarke, and H. triliratus Hall are uncertain because of poor preservation of their type specimens. Use of these names should be confined to the types until better preserved topotypes become available. Finally, H. cooperi (Williams) consists of organisms of uncertain affinities, and the type of H. principalis Hall may be a fragment of Devonian sandstone rather than an organism.

Non-marine and marine palynomorphs were collected from a Telychian through Gorstian rock outcrop located near Allenport, Pennsylvania, USA in the east-central part of the Appalachian Foreland Basin. Close sampling of the section revealed six distinct palynological assemblages of spores, cryptospores, acritarchs and prasinophycean algae, likely deposited in nearshore marine settings. The Silurian Period is a critical time in plant evolution as megafossils found elsewhere indicate that vascular plants (tracheophytes) originated during this interval. Palynoflorules generally show a transition from cryptospore-dominated to miospore-dominated assemblages during the latter half of the Silurian. This transition is evident at Allenport, where over 30 species of miospores and cryptospores are recognized, including two new species: Vermiverruspora cottera and Rugosphaera falloambita. The sequential progression of innovations in exine structure and sculpture seen in the nonmarine palynomorphs at Allenport closely matches evolutionary patterns documented previously in the Appalachian Basin, Avalonia, and elsewhere around the world.

New lower dental material of the fossil hyracoid mammal, Seggeurius amourensis Crochet, 1986, from Eocene deposits of the Southern Atlas in Algeria, has prompted a reevaluation of the genus. The dentition as a whole is first described in detail, thus providing a more precise characterization of the genus than has hitherto been available. Peculiarities, particularly in upper molar morphology, are sufficient to uphold a generic distinction. However, based largely on lower molar morphology Seggeurius amourensis is transferred from the subfamily Geniohyinae to Saghatheriinae. In the upper molars, absence of a postmetacrista and the presence of a preprotocrista continuous with the parastyle are interpreted as primitive features in hyracoids. In the lower molars, extreme reduction of the paracristid and the presence of a mesoconid are also considered primitive for hyracoids. These features together with small size, bunodonty, low crown height, and very simple premolar morphology indicate that Seggeurius amourensis is the most primitive hyrax yet recovered.

Early Ordovician brachiopods Spanodonta floweri (Cooper) and Aporthophyla tianjingshanensis? Fu from peninsular Thailand and the Langkawi Islands, Malaysia, and described and offer important confirmatory evidence for the Ordovician juxtaposition of the Shan-Thai terrane, the North China terrane, and Western Australia.

The mid-Moscovian Izvarino section, Donets Basin, eastern Ukraine, exhibits a complete sedimentological record of siliciclastics (sandstones, siltstones, and calcareous shales) with limestone intercalations and, rarely, coal seams. A multidisciplinary study including microfacies analysis, systematic paleontology (conodonts, fusulinoideans, and ostracodes), biostratigraphy, and paleoecology was focused on the limestones, from limestone L4 through limestone M1, and the adjacent marine shales. Based on sedimentology and fossil associations, the cyclic sediments of the Izvarino section were interpreted as entirely marine deposits of open- and shallow-marine, nearshore and offshore environments with variable terrigenous input.

The well-preserved ostracode faunas are dominated by representatives of the families Amphissitidae, Hollinellidae, Healdiidae, Cavellinidae, and Paraparchitidae. The total fauna is 18 species, of which four are new: Hollinella (Hollinella) granuloba Fohrer, n. sp., Hollinella (Praehollinella) kamenka Fohrer, n. sp., Jordanites krasnodonensis Fohrer, n. sp., and Asturiella donbassica Fohrer, n. sp. The conodont fauna includes 21 species belonging to nine genera and includes one new species: Idiognathodus izvaricus Nemyrovska, n. sp. The conodont faunas are dominated by idiognathodontids. Representatives of Diplognathodus and Neognathodus play a subordinate role. A total of 56 fusulinoidean species referable to 20 genera has been identified; one is new: Eostaffella brazhnikovae Ueno, n. sp.

Conodont and fusulinoidean biostratigraphy led to surprising differences in the age assignment of the Izvarino section and its correlation with the nearby Moscow Basin, Russia. The interval studied is lower Kashirian (Tsninskaya) to middle Kashirian (Narskaya), according to conodonts. It extends to the base of the Podolskian, however, according to fusulinoideans. This discrepancy is possibly related to problems in correlation of the type sections in the Moscow Basin. It calls for reexamination of the mid-Moscovian boundary interval and shows the limits of interbasinal correlations based on a single fossil group.

The upper surface of the corallum of Catenipora rubra was often at or just above the sediment-water interface during life. The vertical growth rate was barely sufficient to keep pace with background sedimentation and possible subsidence of the corallum. Therefore, the colonies were in constant danger of being covered by influxes of sediment, especially during storms. This was compensated by the ability of polyps to respond to sedimentation events and by certain aspects of colony growth. Rapid regeneration following partial mortality involved budding of uninjured polyps and rejuvenation of damaged individuals, in some cases accompanied by a type of axial increase not previously known in tabulate corals. Rapid lateral expansion was possible because small, “immature” polyps could bud and grow in a reptant manner.

Interconnected ranks of the cateniform corallum served to dam shifting sediment at the periphery of the colony. Lacunae within the colony were reservoirs for material that breached peripheral ranks and for sediment that settled on the ranks and was rejected by polyps or removed by passive flow. Polyps comprising the colony were distributed over a large area of the substrate surface, thereby decreasing the probability of complete mortality during sedimentation events and increasing the probability that a sufficient number of individuals would survive to ensure optimum regeneration. The corallum, anchored in the substrate and with sediment filling the lacunae, provided a broad, stable base during high-energy events.

It remains to be established how widespread these growth patterns and strategies were among other corals with cateniform colonies, a form that appeared in many unrelated stocks. Most previous workers emphasized physical strength when considering functional morphology, following a tacit assumption that the corallum rose high above the substrate and was therefore susceptible to breakage during high-energy events. An understanding of the origin of cateniform patterns and the phylogeny of these corals requires knowledge of their modes of growth and life-history strategies, which were genetically as well as environmentally controlled.

Callianassid fossils, preserved within their burrows, collected from Mount Discovery, East Antarctica, provide the first such occurrence in Antarctica as well as evidence for deposition in a shallow marine environment distal to a deltaic system. The age of the specimens, based upon associated dinoflagellate cysts, is late early to middle Eocene.

Quetzalichthys perrilliatae n. gen. and sp. is described based on five specimens from Lower Cretaceous (Middle-Upper Albian) limestones of the Tlayúa Quarry, near Tepexi de Rodríguez, Puebla, Mexico. This new taxon displays the diagnostic characters of Ionoscopiformes, which consequently designate it as a new member of this order of Mesozoic fishes. Additionally, Quetzalichthys n. gen. shares several derived characters with Ionoscopus and Oshunia, including the presence of more than 15 supraneurals, solid and well-ossified monospondylous vertebrae with two lateral longitudinal oval fossae, thin scales of the amioid type, and the ventral surface of some circumorbital bones being intensely pitted. Quetzalichthys perrilliatae is characterized by three unique characters: 26 abdominal centra, 21 principal dorsal fin rays, and two supraorbitals. Additionally, its unpaired fins and tail show conditions intermediate to those found in Ionoscopus and Oshunia. A cladistic analysis of Ionoscopiformes, including both taxa found in the Tlayúa Quarry (Quetzalichthys and Teoichthys), identifies two monophyletic families within the order, Ophiopsidae (including Ophiopsis, Macrepistius, Teoichthys) and Ionoscopidae (involving Ionoscopus, Oshunia, and Quetzalichthys).

Abundant fossil and modern specimens of the bivalve Panomya collected from Hokkaido, northern Japan, belong to five extant species, including P. norvegica and P. trapezoidis (both no longer present in Japan), and P. beringiana, P. nipponica, and P. ampla for modern specimens. I examine the taxonomy for these species around Japan and also for the extinct P. simotomensis and P. izumo from Japan and discuss the geographic history of Panomya. Panomya originated during the latest Oligocene to middle Miocene in the northeastern Gulf of Alaska. Subsequently, P. simotomensis and P. beringiana appeared in the early to late Miocene of northeastern Asia, while P. izumo and P. trapezoidis appeared in the middle to late Miocene of northeastern Asia and Alaska. Panomya nipponica, P. ampla, and P. norvegica appeared during the Plio–Pleistocene in northern Japan and Bering regions. All extant species evolved in the North Pacific; Panomya trapezoidis and P. norvegica extended their ranges to the North Atlantic in the middle Pliocene and early Pleistocene, respectively, and P. beringiana and P. ampla migrated into the Arctic Ocean in the late Pleistocene to Holocene.

Two species of eoparisocrinid crinoids from the Middle Ordovician Galena Group of northern Iowa and southern Minnesota are described, namely Eoparisocrinus crossmani n. sp. and E. grandei n. sp. The post-larval development of Eoparisocrinus crossmani is examined. Crinoid arms grow by addition of new plates at their distal tips in conjunction with calcite deposition on old plates. New branches appear where axillary plates are initiated. Consequently, the growth rates for number of brachials and length of food-gathering system compared to crown volume are much faster than if the animals were isometric. The number of food particles collected is related to the number of food-catching tube-feet, which can be estimated if the length of the arms and height of the covering plates are known. The size of the largest food item is constrained by the food groove width. Thus, food-gathering capacity is the number of food-catching tube-feet multiplied by food groove width. The food-gathering capacity increases more rapidly than if the animal grew isometrically, and the ratio of food-gathering capacity: crown volume only declines slightly over the known growth range. All Ordovician cladid crinoids examined follow nearly identical ontogenetic trajectories. The ecological niche of a stalked crinoid is related to four basic parameters: stem length, food groove width, tube-foot spacing, and branch density. Stem length limits the highest elevation above the seafloor. The column of E. crossmani becomes longer during ontogeny due to the formation of new columnals and height growth of old ones. Consequently, individuals gradually “move up” until the adult elevation of about 50 mm is reached. The growth rates of stem length relative to crown size are slow in the youngest and mature animals but rapid in juveniles. The food grooves become wider throughout growth so that older crinoids ate larger food particles than younger ones. The food groove width increases less rapidly than if the shape were constant, because distal plates and branches are more narrow and have more slender food grooves than proximal plates. Growth curves for food groove width versus stem length and elevation were generated for E. crossmani and other crinoids that commonly occur in the same beds. Together, elevation and food particle size define the main dimensions of the niche. The various taxa are more or less separated by different food groove widths at most comparable elevations. This pattern minimizes ecological overlap and probably competition between the different species. The tube-foot spacing of E. crossmani is constant regardless of size, which suggests that it employed the same type of feeding mechanism throughout post-larval ontogeny. The arm branches of adults gradually become less densely spaced relative to the area of water filtered than in juveniles.

Seven fossil leaf species are described from impression fossils collected from the Upper Cretaceous (Maastrichtian) Fox Hills Formation in south-central North Dakota, USA. They are Marmarthia johnsonii n. sp., Nilssoniocladus yukonensis n. comb., Nilssoniocladus comtula n. comb., Mesocyparis borealis, Rhamnus salicifolius, Paloreodoxites plicatus, and Zingiberopsis magnifolia. These species represent some of the elements of the Fox Hills flora that have paleogeographic ranges to the northwest (N. yukonensis, N. comtula, and M. borealis) and to the southwest (M. johnsonii, R. salicifolius, P. plicatus, and Z. magnifolia) of the Fox Hills type area. The identification and reappraisal of these species represent an effort to understand the biogeographic relationships of Late Cretaceous floras across the Northern Hemisphere.

The Port au Port Group of western Newfoundland is a sequence of Upper Cambrian (Marjuman–Sunwaptan) shallow subtidal–supratidal carbonates and fine siliciclastics that are organized into three large scale sedimentary grand cycles. Low diversity trilobite faunas from the Marjuman and Steptoean portions (March Point and Petit Jardin Formations) include 17 species that are assigned to 16 genera; one species, Coosina kindlei, is new. Biostratigraphic analysis confirms earlier suggestions that the grand cycles boundaries record major intervals of onlap that can be recognized in other parts of North America and may be related to eustatic sea level rises.

The Lower Cambrian sequence south of the town of Caborca in northwestern Sonora, Mexico, has yielded the trilobites Nevadia ovalis n. sp. and Judomia orbis n. sp., plus an incomplete fallotaspid cephalon. The Nevadella Zone of Fritz (1972) can now be recognized in the Puerto Blanco Formation, and fossils from the middle part of the formation strongly suggest the presence of the Fallotaspis Zone. The new fossils permit improved correlation of the Mexican sequence to sections in the United States and to Lower Cambrian stages of China and the Soviet Union.

Twenty-four fragmentary specimens and numerous disarticulated plates of a new clavate agelacrinitid edrioasteroid were collected from the Middle Pennsylvanian Naco Formation in central Arizona. Spiraclavus nacoensis n. gen. and sp. is similar to Lepidodiscus laudoni (Bassler, 1936) and Discocystis kaskaskiensis (Hall, 1858), but differs in the direction of ambulacral curvature and in the number and arrangement of ambulacral cover plates. Numerous well-preserved, disarticulated plates allow a full description of plate morphologies from various parts of the theca. The entire oral surface is rigidly constructed of tessellate plates. Interlocking serrate sutures between successive floor plates add strength. Plate sutures in the flexible and telescoping portions of the theca (recumbent zone and pedunculate zone, respectively) are beveled, allowing considerable imbrication and potential for thecal extension.

The associated fauna indicates that the unit containing the edrioasteroids was deposited on an offshore, subtidal, marine carbonate shelf with occasional siliciclastic influxes. The specimens of Spiraclavus nacoensis were buried by siliciclastics, probably during storm events.

The Lower Ordovician middle Beekmantown Group is a very thin carbonate platform succession on the northern New York Promontory that thickens north into the Ottawa aulacogen near Montréal. The Tribes Hill Formation (Rossodus manitouensis Zone) records the earliest Ordovician (late Skullrockian, late early Tremadocian) eustatic high that submerged Laurentia, and produced the lowest Ordovician sequence along the New York Promontory. These dolostones are succeeded in the Beekmantown, New York, area by late Tulean?–Blackhillsian transgressive systems tract quartz arenites of the lower Fort Cassin Formation (Ward Member). The “Fort Ann Formation” (middle Stairsian, upper Tremadocian) of the southern Lake Champlain lowlands (=Theresa Formation sandstones in the Ottawa graben) is absent at Beekmantown, and moderate Stairsian (late Tremadocian) eustatic rise apparently did not inundate the Beekmantown area after Skullrockian–Stairsian boundary interval offlap. Highstand carbonates of the upper Fort Cassin Formation [Sciota Member = “Spellman Formation” and “Ogdensburg Member” of the “Beauharnois Formation” in the Montréal area; designations abandoned] at Beekmantown yield diverse conodonts seemingly characteristic of the Oepikodus communis–Fahraeusodus marathonensis Zone (new). However, associated trilobites, particularly Carolinites tasmanensis (Etheridge, 1919), show a correlation with the upper Trigonocerca typica (trilobite) Zone of the Utah and the overlying Reutterodus andinus (conodont) Zone. This abrupt early Blackhillsian lithofacies change features the appearance of chitinozoans and conodonts known from marginal successions, and records the Laignet Point highstand (new). This highstand is recognized across Laurentia on the west Newfoundland and southern Midcontinent platforms. It is recorded on the east Laurentian continental slope by lower Oepikodus evae Zone dysoxic black mudstone in the Taconian allochthons. Taxonomic re-evaluations include Ulrichodina Branson and Mehl, 1933, with its genotype species U. abnormalis (Branson and Mehl, 1933) emend., as the senior synonym of Colaptoconus Kennedy, 1994; Eucharodus Kennedy, 1980; and Glyptoconus Kennedy, 1980. Paraserratognathus An in An et al., 1983, emend. is the senior synonym of Wandelia Smith, 1991 and Stultodontus Ji and Barnes, 1994. Tropodus Kennedy, 1980 is the senior synonym of Chionoconus Smith, 1991. The trilobite fauna of the Sciota Member includes species of Isoteloides, Benthamaspis, Acidiphorus and Carolinites, of which I. fisheri is new.