Aerliceaster nexosus n. gen. n. sp. (Echinodermata), one of the oldest of known asteroids, is based on six specimens from the Floian (Early Ordovician) Garden City Formation of Idaho, and Kolataster perplexus n. gen. n. sp. is based on two specimens from the Sandian (Late Ordovician) Mifflin Formation of Illinois. Although the asterozoan skeleton is subdivided into few ossicular categories, evolutionary derivations of all the categories are not fully established, and therefore published evaluations differ. Beginning with phylogenetic work placing asteroid ancestry within the Somasteroidea together with the new taxa described herein, aspects of early asteroid morphology are evaluated and ambiguities in need of further study identified. Uncertainties are considered to be founded in rapid early asterozoan diversification and the scanty fossil record.

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Species of Baculites are important marker fossils in the Upper Cretaceous rocks of the Western Interior of the United States and provide indices for 20 of the 29 Campanian and Maastrichtian zones recognized by Cobban (in Gill and Cobban, 1966; Cobban, 1977). They often occur in rock-forming proportions (Gill and Cobban, 1966, Pl. 11, fig. 3) and are common up through the lower Maastrichtian Baculites clinolobatus zone. In the type area of the Fox Hills Formation in west-central South Dakota, B. clinolobatus is present in the lower part of the Mobridge Member of the Pierre Shale, but Baculites are rare or absent in the rest of the member as well as in the overlying Elk Butte Member that forms the uppermost part of the Pierre Shale (Waage, 1968, p. 50, 51, fig. 6). Only the diminutive Baculites columna Morton, 1834, has been noted from the succeeding Fox Hills Formation (Waage, 1968). The highest marine Cretaceous rocks of the Western Interior are characterized instead by Sphenodiscus and a range of scaphitid species (Hoploscaphites, Discoscaphites). It is therefore of some interest to describe, for the first time, the baculitids from the very high Cretaceous of the Western Interior. The material described below was collected from the Fox Hills Formation by N. L. Larson, P. L. Larson, and R. A. Farrar of the Black Hills Institute of Geological Research, Hill City, South Dakota. We are grateful to them for allowing us to describe this interesting collection. Specimens cited below are deposited in the collections of the Black Hills Institute (BHI) and in the U.S. National Museum of Natural History (USNM) in Washington, D.C.

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).

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.

Phragmolites lissoni new species is described from 11 specimens found in the Sandbian Calapuja Formation near Calapuja in Peru. The deposits are part of the Central Andean Basin. This is the hitherto only systematically described Ordovician gastropod from Peru. The species is from a brachiopod-dominated siliciclastic sequence and is associated with bryozoans. Most specimens are preserved as external molds, but latex casts yield excellent details of shell ornamentation and are used as a basis for evaluating this feature in the genus. The characteristic ornamentation of Phragmolites should be called corrugated lamellae, and the individual elements on these should be referred to as flutes. A descriptive terminology for these is suggested. The development and shape of the corrugated lamellae and flutes could be biomechanical process. A second component in lamellar formation is the alternation between regular incremental growth and formation of a lamella. Phragmolites is mainly found in shallow-water carbonate facies from tropical latitudes in the Sandbian and a mid-latitude presence in Peru is unexpected. Brachiopods from the same section in Calapuja show affinities with faunas of the Mediterranean margin of Gondwana but also weak links with Avalonia. Phragmolites is found abundantly in deeper-water facies in Laurentia, and a broad tolerance to facies and temperature and possible planktotrophy might have allowed a wide geographical dispersal of the genus. The scant record of Ordovician gastropods in the Central Andean Basin precludes comparison with the disparate record of the Ordovician gastropod taxa from the Precordillera, which do not include Phragmolites.

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Llanocystis wilbernsensis n. gen. n. sp. (Eocrinoidea, Echinodermata) is described based on three specimens from the Furongian Point Peak Shale Member of the Wilberns Formation in central Texas. It displays a unique morphology including a very long stem constructed with holomeric columnals, few feeding appendages, and a polyplated theca. The specimens occur in an intraformational conglomerate deposited in a proximal carbonate platform environment and represent an example of the poorly documented “pelmatozoan” radiation that occurred in proximal facies by the end of the Cambrian.

Actinocamax cobbani, a new belemnitellid species from the middle Coniacian of Montana and Wyoming, is described, including univariate and bivariate biometric analyses. The species is stout and medium sized, lanceolate or strongly lanceolate in ventral view, and has adorally a low cone-shaped alveolar fracture. It may be granulated. It is compared to species of Actinocamax Miller and Gonioteuthis Bayle from the North American and North European paleobiogeographic provinces. The importance of various morphological characters, such as the shape of the guard and the structure of the adoral end, are discussed. The majority of the belemnitellids of the North American Province are endemic and the stratigraphic distribution is punctuated during the Late Cretaceous, suggesting short-lived migrations of populations from the North European Province.

Leviceraurus mammilloides n. gen. and sp. is an Ordovician cheirurine trilobite which occurs in limestones and shales of the Hallowell and Hillier Members of the Cobourg Formation, southern Ontario. It is a probable descendant of Ceraurus.

Apparatus-based conodont taxonomy has organized the plethora of generic and specific names of form-based taxonomy into a more biologically and phylogenetically sound taxonomy (Schopf, 1966; Webers, 1966; Bergström and Sweet, 1966; Sweet and Bergström, 1972; Rhodes and Austin, 1981; Sweet, 1981, 1988). In the transition from form-based to apparatus-based taxonomy, some conodonts that are not very common, or that have only one or two element types in their apparatus, have remained in a state of form-based taxonomy limbo. An example of this is Trichonodella? tricurva (Schopf, 1966). This relatively uncommon species was known from only one element type (Schopf, 1966) and has not been used in biostratigraphy. Schopf (1966) questioned the generic assignment of T.? tricurva and noted its distinct morphology. Sweet and Bergström (1972) indicated that the type species of Trichonodella (Branson and Mehl, 1948) is a junior synonym of Plectodina aculeata, or of a closely related Plectodina species. Trichonodella? tricurva does not fit within the apparatus-based generic concept of Plectodina (Sweet, 1981), and it is therefore inappropriate to refer it to Trichonodella or Plectodina. No genus contains a tertiopedate element that is morphologically similar to the holotype of T.? tricurva (Schopf, 1966). Additional material from strata that are in part coeval with the stratum typicum of T.? tricurva supports the idea that T.? tricurva represents a new genus. The new genus Schopfodus is proposed for the conodont elements described by Schopf as T.? tricurva and the associated elements of its apparatus.

A remarkable fossil assemblage composed of five gastropod taxa is described from the Early Miocene of Santa Cruz (Patagonia, Argentina) in southernmost South America. The assemblage includes extinct and living genera South America, and on geographic distributions and represent background new information on spatial and across time distributions as well as identification of new taxa. A new taxon, Patagocharopa enigmatica n. gen. n. sp., is tentatively assigned to Charopidae. Gastrocopta patagonica n. sp. (Vertiginidae) represents the oldest record of Gastrocopta in Argentina and the southernmost record for the Americas. Punctum patagonicum n. sp. (Punctidae) represents the first record of Punctum for continental South America, and characterized by a protoconch with traces of axial costulae and a teleoconch with strong radial ribs. Zilchogyra miocenica n. sp. is the first Miocene record of the charopid genus Zilchogyra. Fragments of a possible Scolodonta (Scolodontidae) are recorded. Overall, the assemblage represents an important and useful paleoenvironmental tool. This fauna suggests that a more temperate and humid environment than today—with a more dense vegetation cover—was prevalent at this site during the Early Miocene.

A new genus and species of turrid neogastropod, Kyllinia parentalis, is described based on three shells from the Pliocene (North Italy) and the Pleistocene (northwestern Peloponnesus) of the central Mediterranean area. the new taxon is compared to the buccinid (sensu lato) genus Metula H. and A. Adams, 1853 with which it shows a few superficial similarities mainly limited to the latticed sculptural pattern of the teleoconch. Kyllinia parentalis is placed in the turrid subfamily Mangeliinae on the basis of teleoconch characters (double sinuosity of the outer lip and the short, forward curved anterior canal) and protoconch (a characteristic pattern formed by narrow axial riblets giving a coronated suture to the larval shell). These taxonomic characters, together with the almost clathrate teleoconch sculpture, form an original combination within the Mangeliinae, thus justifying the description of a new genus. the Recent species Philbertia marchadi Knudsen, 1956 (for which we consider the previous attributions to Philbertia Monterosato, 1884 and Diaugasma, Melvill, 1917 incorrect) from the Republic of Guinea and Angola closely resembles K. parentalis, but differs in having axial folds on early teleoconch whorls, a more slender shell, and a proportionally taller last whorl. Philbertia marchadi fits well with the characteristics of the herein described genus, so that we propose the new combination Kyllinia marchadi (Knudsen, 1956). Kyllinia parentalis, a species originated in the Mediterranean Pliocene, is to be considered as the ancestor of K. marchadi. Kyllinia parentalis should be regarded as a meaningful marker in recognizing warm Mediterranean Pleistocene events.

Ordovician open marine Lagerstätten are relatively rare and widely dispersed, producing a patchy picture of the diversity and biogeography of nonmineralized marine organisms and challenging our understanding of the fate of Cambrian groups. Here, for the first time, we report soft-bodied fossils, including a well-preserved marrellomorph arthropod, fragmentary carapaces, and macroalgae, from the Late Ordovician (Katian) Upper Member of the Kirkfield Formation near Brechin, Ontario. The unmineralized elements and associated exceptionally preserved shelly biota were entombed rapidly in storm deposits that smothered the shallow, carbonate-dominated shelf. The marrellomorph, Tomlinsonus dimitrii n. gen. n. sp., is remarkable for its ornate, curving cephalic spines and pair of hypertrophied appendages, suggesting a slow-moving, benthic lifestyle. Reevaluation of marrellomorph phylogeny using new data favors an arachnomorph affinity, although internal relationships are robust to differing outgroup selection. Clades Marrellida and Acercostraca are recovered, but the monophyly of Marrellomorpha is uncertain. The new taxon is recovered as sister to the Devonian Mimetaster and, as the second-youngest known marrellid, bridges an important gap in the evolution of this clade. More generally, the Brechin biota represents a rare window into Ordovician open marine shelf environments in Laurentia, representing an important point of comparison with contemporaneous Lagerstätten from other paleocontinents, with great potential for further discoveries.

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The outcrop at Whiterock Canyon Narrows, Nevada, is the stratotype for the Middle Ordovician Whiterockian Series in Laurentia. Contrasts in the distribution of trilobites and conodonts between two parallel sections at the stratotype demonstrate the presence of an unconformity separating Ibexian faunas (the historic trilobite Zone J, the more recent restricted “Pseudocybele nasuta” trilobite Zone, the Reutterodus andinus conodont Zone) from overlying Whiterockian faunas (Zone L, the Psephosthenaspis pseudobathyurus trilobite Zone, the Orthidiella brachiopod Zone, the Tripodus combsi conodont Zone). The unconformity represents the erosional loss of a minimum of 10 m of shale and bedded limestone within the upper Ninemile Formation. In comparison to more continuous section in the Ibex region, Utah, the equivalent to the thin Psephosthenaspis microspinosa trilobite Zone and, possibly, the uppermost interval of the underlying “P. nasuta” Zone are missing. Illaenus welchi new species is described from the Whiterockian faunas of the upper Ninemile and Antelope Valley formations.

The fossil record of the family Camerobiidae has been represented by only one species, Neophyllobius succineus Bolland and Magowski, 1990, described from Eocene Baltic amber. These prostigmatan mites are distinguishable by their distinctly long and slender stilt-like legs, and they are associated with aboveground vegetation where they hunt for other small invertebrates. This paper enhances the knowledge of fossil stilt-legged mites. Two new fossil species, N. electrus new species and N. glaesus new species, are described from samples of Baltic amber, and remarks on their morphology and taphonomy are provided. The discovery is complemented with a discussion on morphological singularities (the shape of the prodorsum, the location of setae h1 and h2 in living specimens, and lengths of genual setae), an anomaly of hypertrophied seta (found in the N. glaesus holotype), and some biogeographical issues.

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Nectocaridids are soft-bodied Cambrian organisms that have been controversially interpreted as primitive cephalopods, at odds with the long-held belief that these mollusks evolved from a shell-bearing ancestor. Here, I document a new nectocaridid from the Whetstone Gulf Formation, extending the group's range into the Late Ordovician. Nectocotis rusmithi n. gen. n. sp. possesses a robust internal element that resembles a non-mineralized phragmocone or gladius. Nectocaridids can be accommodated in the cephalopod total group if the earliest cephalopods (1) inherited a non-mineralized shell field from the ancestral mollusk; and (2) internalized this shell field. This evolutionary scenario would overturn the traditional ectocochleate, Nautilus-like reconstruction of the ancestral cephalopod, and indicate a trend towards increased metabolic efficiency through the course of Cambrian–Ordovician evolution.

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The new fossil micromammal assemblage of Çapak represents a mixture of both Anatolian and European faunal elements. The locality is very important for understanding faunal evolution in the less well-known time interval at the end of the early Miocene of western Anatolia. In Çapak, nine species of rodents and one species of ochotonid were encountered: the hamsters Democricetodon gracilis, Megacricetodon primitivus, Eumyarion aff. E. montanus, Cricetodon cf. C. aliveriensis, Cricetodon sp., and Karydomys cf. K. strati, the mole-rat Debruijnia sp., the squirrel Aliveria luteyni, the dormouse Myomimus tanjuae n. sp., and the pika Albertona balkanica. The assemblage is referable to Anatolian local zone E or MN unit 4. The relative abundance of the various genera is markedly different from that of the older early Miocene assemblages, suggesting that the environment in Anatolia became drier and had a more open landscape.

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Members of the echinoid order Spatangoida, a highly diverse and abundant marine invertebrate clade, were important denizens of the Cretaceous Western Interior Seaway (WIS), an epicontinental seaway that divided North America in two during an interval of greenhouse conditions between roughly 100 and 65 million years ago. A phylogenetic analysis of spatangoids was conducted using a character matrix of 32 characters from 21 species. Species that occur in the WIS were considered comprehensively, and species from other regions such as South America, Europe, and North Africa were also incorporated into the analysis. Phylogenetic patterns retrieved are largely congruent with preexisting family-level classifications; however, species within several genera, especially Hemiaster and Heteraster, need to be reassigned so that classification better reflects phylogeny. The genera Washitaster and Heteraster are closely related, as are Mecaster, Palhemiaster, and Proraster; Pliotoxaster, Macraster, and Hemiaster; and Micraster and Diplodetus. Biogeographic patterns were also considered using the phylogeny, and several episodes of vicariance and range expansion were identified. These were possibly related to some of the various major episodes of sea-level rise and fall during the Cretaceous. In particular, Valangian–mid-Aptian regressions may have caused vicariance within Heteraster and Washitaster while other early spatangoid vicariance may be related to regressions during the late Aptian–early Cenomanian. Further, vicariance caused by regressions during the mid-Cenomanian–Maastrichtian may have driven diversification within Micraster and Diplodetus. Last, transgressions during the late Aptian–early Cenomanian seem to have spurred prominent range expansions in Mecaster and Hemiaster.

Protandrous sex change (sex change from male to female) is one of the diverse sexual expressions exhibited by bivalves, but its expression in the shell is quite rare. Previous studies on living and fossil astartids suggest a relationship between protandrous sex change and the formation of crenulations on the ventral shell margin at later ontogenetic stages. Here we report the formation of such crenulations in the Early Jurassic astartid Nicaniella rakoveci (Kuhn, 1935) from the Amaltheenton Formation at Buttenheim, Franconia. This is the earliest known record of protandrous hermaphroditism in fossil bivalves, predating previous reports by at least 13 Myr. A principal component analysis of linear size measurements and Fourier shape analysis of the shell outlines revealed that the outline of Nicaniella rakoveci specimens varies from subquadrate to subcircular, but this variation is independent of the presence or absence of crenulations and therefore not associated with sex. Crenulated specimens exhibit a lower height/inflation ratio than non-crenulated ones, suggesting that the protandrous females have more inflated valves than the males. The formation of crenulations was probably related to allocation of resources for reproduction. The most likely function of the crenulations was to increase the internal shell volume in the female stage to accommodate more eggs rather than being an adaptation against predation as often assumed for other bivalves. The formation of crenulations is part of the protandrous life history and probably is controlled by a genetic mechanism that is also responsible for sex change.