The continuous sequence of Maastrichtian to Paleocene sediments exposed in the Sierra Dorotea area in southwestern Santa Cruz (Argentina) contains a rich molluscan fauna with many elements characteristic of the Weddellian Faunistic Province. The presence in this fauna of genera such as Taioma, Heteroterma, Fyfea, Zemacies, and Priscaphander suggests close affinities with faunas of similar age from New Zealand, further supporting the existence of continuous shallow-sea conditions along the southern margin of the Pacific Ocean during the end of the Cretaceous and beginning of the Tertiary. In this paper 25 species are described, of which six are new: Pseudofax costellatus n. sp., Taioma patagonica n. sp., Heteroterma elegans n. sp., Fyfea beui n. sp., Priscaphander sanjosensis n. sp., and Priscaphander bracaccinii n. sp.

Foliaster transversus n. gen. and sp. (Echinodermata: Asteroidea) is assigned to the Ordovician through Devonian family Palasteriscidae; the other genera included in the family are Palasteriscus and Platanaster. Platanaster is redescribed; both it and Foliaster are thought to have been suspension feeders that extended their arms into the water column. Ampullar basins in both were external; there are no podial pores. The strongly petaloid arm of Foliaster with widely separated podial basins is unique.

Two competing phylogenies have been offered for the origin of stelleroids, one treating edrioasteroids as ancestral, the other favoring crinoids. In the latter hypothesis, the Palasteriscidae is the primitive asteroid family, and Platanaster is an example of the first true asteroids. Both hypotheses are here considered to lack adequate support; stelleroid origins remain problematic.

New Devonian fossil material from Bolivia includes internal molds of two species of paleotaxodont bivalve, Palaeoneilo musculosa (Knod) and P. pondeana (Hartt and Rathbun), with numerous accessory muscle scars. The unusual pattern of these scars appears to have been derived from excessive splitting. These muscle scars are described and a tentative interpretation is made. An adaptative role cannot be determined with certainty and it appears that these patterns were short-lived novelties without later success.

Maastrichtian strata of the Zumaya-Algorta Formation of southwestern France and northeastern Spain record a major pulse of extinction among inoceramid bivalves well before the Cretaceous–Tertiary (K–T) boundary. Inoceramids are the most abundant macrofossils preserved in the study sections; at least six species of Inoceramus [I. (Endocostea) aff. I. (En.) balticus Giers, I. (En.) pteroides Giers, I. (Platyceramus) aff. I. (Pl.) cycloides Wegner, I. (Trochoceramus) nahorianensis Kociubynskij, I. (Tr.) morgani Sornay, and I.(?) goldfussianus d'Orbigny] are common to abundant in lower Maastrichtian strata. However, all six species disappear over a few tens of meters of section near the base of the upper Maastrichtian, as defined by the first appearance of the planktonic foraminifer Abathomphalus mayaroensis. Tenuipteria argentea (Conrad), which has not been recovered from the lower Maastrichtian portions of the sections, occurs at low abundances through the upper Maastrichtian, disappearing within 10 cm of the K–T boundary.

The mid-Maastrichtian extinction interval among inoceramids occurs within the upper Globotruncana gansseri to lower Abathomphalus mayaroensis planktonic foraminiferal zone, in nannofossil zone 24 to 25A, in the Anapachydiscus fresvillensis ammonite zone, in magnetochron 31N, and near the base of a change in slope of the seawater strontium curve, all as recognized by previous studies in one or more of the study sections. Whereas the new data presented here are not global in extent, the observed distribution of inoceramids may be the local manifestation of global oceanic changes during the mid-Maastrichtian.

Crinoids are reported from the New Zealand Paleocene for the first time and include rare articulated columnals and brachia with pinnules. These specimens of Metacrinus sp. (Isocrinidae) are present in basal, fossiliferous, coarse-grained, quartzose sediments of the Kauru Formation, a few centimeters above schist basement, in the Kakanui Valley, North Otago. The crinoid-bearing facies probably represents earliest onlap or a storm surge onto a wave cut platform; sedimentological and paleontological evidence indicates a moderate- to high-energy environment. The crinoids were most probably buried rapidly while alive or shortly after death. The presence of isocrinids in the Kauru Formation and younger Paleogene strata reveals that the supposed shift of some isocrinids from a shallower to a deeper environment actually occurred much later in the Paleogene, and not the Late Cretaceous as previously supposed. Associated molluscs indicate a mid to upper “Wangaloan” Stage (local), equivalent to mid Paleocene. A summary of the New Zealand crinoid fossil record is presented.

Morphometric analysis demonstrates that Strepsidura ficus (Gabb) of Harris (1895), from the lower middle Eocene Reklaw and Queen City Formations of Texas, is specifically distinct from Whitneya ficus Gabb (1864) of the Californian Eocene. Accordingly, the new name Strepsidura harrisi is proposed for the Texas species. Strepsidura s.s. is represented in North America by S. ficus (Gabb), S. harrisi n. sp., and an unnamed species closely related to S. harrisi in the upper Paleocene Sequin Formation of Texas. Strepsidura s.s. apparently originated in the Old World Tethyan Realm during the Paleocene and subsequently spread to North America.

Eospirifer praecursor n. sp. is the oldest known eospiriferine, probably ancestral to the entire Spirifer group. It is described here based on external and internal mold material from the uppermost part of the Changwu Formation (mid-Ashgill, Late Ordovician), Hejiashan, Jiangshan, western Zhejiang, East China. A study of the ontogeny of E. praecursor n. sp. suggests that the cardinalia of early growth stages are more similar to those of early atrypoids rather than to those of the orthoids but the brachidia in these earliest Eospirifer are still unknown. The possibility that eospiriferines were derived from an atrypoid stock cannot be excluded. All early eospiriferine species recorded from the Ashgill, Rhuddanian, and early Aeronian are reviewed for comparison. Their morphological diversification reveals early evolutionary experimentation. Based on the Ashgill occurrence of Eospirifer, it is likely that East Asia may be considered as one of the eospiriferine source areas.

Protaspides and later growth stages are described and discussed for the Ordovician trinucleid trilobite Cryptolithus tesselatus Green and the raphiophorid Lonchodomas chaziensis Shaw. A small triangular rostral plate is described for a single protaspid instar in both Cryptolithus and Lonchodomas. The presence of this small sclerite in the ontogeny of these taxa supports the origin of the Trinucleoidea from the Ptychopariida through reduction in and then fusion or loss of the rostral plate. Earlier and later growth stages have fused ventral sclerites, with no signs of connective sutures. All members of the Trinucleoidea with known ontogenies share similar small, ovoid asaphoid protaspides, with distinct axes and varying numbers of sharp, conical to subtubular, submarginal spines on the dorsal exoskeleton and marginal spines on the hypostome. Two protaspid instars are identified in both Cryptolithus and Lonchodomas, sharing many characters that indicate homologous levels of development. A single origin for the median suture of the Asaphida is supported, with an anterior rostellum as its precursor.

GONIAT is designed as tool for investigations on the systematics of the Paleozoic ammonoids, their paleogeographic distribution, and their biostratigraphic range. This data base management system provides not only determinations based on morphological characteristics, but also information on occurrence, duration, literature, and phylogenetic relationships of every taxon of family, genus, and species levels. GONIAT is a relational data base. It consists of six independent data bases connected by three link information files: TAX for taxonomy, MORPHA and MORPHB for all distinctive morphological characters in adult or early and middle growth stages, LIT for literature, LOC for localities, and BOUND for biostratigraphy. In order to provide relevant time planes that can be used on a worldwide scale, radiometric dates as well as biostratigraphic names are used.

Dimeropyge öpik, 1937, is a genus currently composed of at least 14 similar Middle (predominantly) to possibly lowest Upper Ordovician species from Laurentia (13 species) and Baltica (one species). Possible Lower Ordovician specimens have been illustrated by Ross (1951). Dimeropyge clintonensis Shaw, 1968, is redescribed, based upon additional material of mature topotypes. A new species of Dimeropyge, D. speyeri, is proposed for material from the Esbataottine Formation in the Mackenzie Mountains, northwestern Canada, previously described as D. clintonensis. A phylogenetic analysis of 10 of the 14 species of this genus is presented (the other species are less completely known, and are related to the analyzed species in a more traditional manner). Ontogenies from protaspid to holaspid stages are provided for D. clintonensis, D. speyeri, and D. virginiensis Whittington and Evitt, 1954. The larval stages of these species are very similar, supporting the close relationship between species assigned to Dimeropyge.

The distributional patterns of reticulate sculptures, corresponding to those of the underlying epidermal cells, of two Baffinicythere species (Ostracoda, Crustacea) are discussed from a geometrical point of view to understand whether they are under some rule or not. Reticulation geometry has been quantified by applying the method of Dirichlet domains defined as convex polygons, each being demarcated by bisectors normal to the lines connecting neighboring pairs of points. Studies of the distributional patterns of reticulation during growth reveal that these polygons become closer to Dirichlet domains and are dominated by hexagonal or subcircular fossa outlines toward the adult stage, and ultimately reach an equilibrium and stable pattern at maturity.

The condensed Upper Albian to Lower Cenomanian deposits of the Helvetic Shelf of France and Switzerland yield diverse ammonite faunas including representatives of the family Lyelliceratidae, subfamily Stoliczkaiinae that is the origin of the Upper Cretaceous Acanthoceratidae and its descendants, as well as representatives of the dwarf stoliczkaiine offshoot, the family Flickiidae, subfamily Salaziceratinae. The following are described and referred to the Upper Albian Mortoniceras inflatum Zone: Neophlycticeras (N.) brottianum (d'Orbigny, 1841), N. (N.) rhodanense Delamette, 1983, N. (Protissotia) itierianum (d'Orbigny, 1841), and Zuluscaphites helveticus n. sp. From the Upper Albian Stoliczkaia dispar Zone come Neophlycticeras (N.) blancheti (Pictet and Campiche, 1859), N. (Paradolphia) priscum Casey, 1965, Stoliczkaia (5.) notha (Seeley, 1865), S. (S.) tenuis Renz, 1968, S. (Lamnayella) tetragona Neumayr, 1875, Cenisella bonnetiana Pictet, 1847, Zuluscaphites orycteropusi Van Hoepen, 1955, Salaziceras (S.) salazacense (Hébert and Munier-Chalmas, 1875), and S. (S.) breistrofferi Scholz, 1979. The Lower Cenomanian Mantelliceras mantelli Zone, Neostlingoceras carcitanense Subzone yields Stoliczkaia (Stoliczkaia) villoutreysi Casey, 1965, S. (Lamnayella) tetragona Neumayr, 1875, and S. (Shumarinaia) hashimotoi Matsumoto and Inoma, 1975.

A new Tertiary gastropod genus, Peonza n. gen., is described, along with two new species, P. torquata from southern Argentina and P. benjamina from southern Chile. These muricacean gastropods, of uncertain familial status, occur in the late Eocene San Julián Formation and in the late Oligocene to early Miocene? Monte León Formation, Santa Cruz Province, Argentina. They also were recorded in the (probably) Oligocene Magellanian beds in Tierra del Fuego, Argentina, and in early Miocene deposits of the Tres Montes region in the Chilean Canals. In spite of the small number of specimens, Peonza n. gen. seems to have had a wide geographic and temporal distribution.

The brachiopod fauna that presently lives in the seas off the coasts of Namibia, South Africa, and southern Moçambique comprises 35 named plus seven unnamed species belonging to 26 genera, making it one of the most diverse in the world. Within the fauna are some species that are confined to the warm waters of the east coast, some that are restricted to the cold west coast waters, and others that enjoy a more widespread distribution. The geographic distribution of species is believed to be controlled by the two major oceanographic systems operating off southern Africa, namely, the Agulhas Current on the east and the Benguela Upwelling System on the west.

Among the species that live off the west and south coasts are many that appear to have evolved in situ during times of pronounced environmental stress since the late Miocene. The fauna living off the east coast shows strong similarity with others in the Indian Ocean and it is inferred that many of the species migrated into the South African region by way of the ocean current systems that were established by the mid-Pliocene.

Descriptions of Xenobrochus naudei and the previously undescribed Argyrotheca sp. and Amphithyris cf. A. richardsonae are provided.

The Dayton, Osgood, and Laurel Formations and the Euphemia, Springfield, and basal part of the Cedarville Dolomites near the axis of the Cincinnati Arch in northeast Preble County, Ohio, belong in the uppermost part of the Ozarkodina sagitta rhenana to lower part of the Ozarkodina? crassa Chronozone and are late early to middle Wenlockian in age. The Dayton–Cedarville succession on the eastern flank of the Cincinnati Arch in north-central Greene County, Ohio, belongs in the uppermost part of the Pterospathodus celloni to upper part of the Ancoradella ploeckensis Chronozone and is late Llandoverian to early middle Ludlovian in age.

The sea transgressed across the exposed and eroded Brassfield Formation to begin deposition of the Dayton Formation on the eastern flank of the Cincinnati Arch in Greene County, Ohio, during the late Llandoverian and completely flooded all of west-central Ohio by the late early Wenlockian. The region remained covered by a sea of fluctuating depth during deposition of the Dayton Formation–Cedarville Dolomite succession from the Wenlockian through early middle Ludlovian.

Kockelella walliseri (Helfrich) evolved from K. ranuliformis (Walliser) during the middle Wenlockian (upper part of Ozarkodina sagitta rhenana Chronozone) by development of a lateral process adjacent to the cusp on the Pa element and by minor modification of the Pb element and some of the ramiform elements. Specimens from upper Llandoverian and lower Wenlockian strata previously assigned to K. walliseri belong to a different species, Kockelella sp. A Fordham, 1991. The evolutionary trends in the K. walliseri lineage, progressive restriction of the basal cavity and increasing development of the length of the lateral processes in the Pa element, parallel the trends in the K. amsdeni–K. stauros–K. variabilis lineage and resulted in the divergence of Kockelella cf. K. stauros Bischoff, 1986, from the main lineage in the middle Wenlockian.

Alcymene n. gen. comprises a monophyletic group of calymenids known from the Ludlow Series of Sweden and the British Isles. The sister species Alcymene alveus and A. lindstroemi n. gen. and spp. (Hemse Beds, Gotland, Sweden) are most closely related to the type species A. neointermedia (Richter and Richter), which occurs in overlying and underlying strata at nearby localities. Structural modification of A. alveus and A. lindstroemi, especially the development of a greatly broadened and troughed librigenal border, can be interpreted as “snowshoe” adaptations for increased stability on an offshore mud substrate.

Kheraiceras Spath, 1924, is known mainly from macroconchs. Matching of dimorphic pairs at species level is difficult due to the rarity of microconchs and consequent difficulty in establishing contemporaneity. The present study reveals dimorphism within Kheraiceras cosmopolitum (Parona and Bonarelli, 1895) from the lower part of the Callovian Chari Formation, Kutch, India, where microconch closely resembles macroconch except for the size, being about three times smaller and having an aperture characterized by terminal construction. The evolution of Kheralceras from Bullatimorphites Buckman is based on macroconchs only. The discovery of coeval microconch specimens and study of known microconchs within the lineage indicate “parallel” evolution in macro- and microconchs and improves the understanding of evolutionary trends that involve complex heterochronic processes.

An Early Pennsylvanian tetrapod trackway, referred to Notalacerta missouriensis Butts, was found in the Rockcastle Sandstone Member (Westphalian A, Upper Carboniferous) of the Lee Formation in McCreary County, Kentucky. Terrestrial characteristics of the trackway, such as digit length, claw marks, gait, and tail drag, suggest that it was made by a member of the primitive reptile family Protorothyrididae. If identified correctly, this is the oldest known reptile trackway in North America. The animal that made the trackway was approximately 0.4 m in length. The pes tracks are slightly larger and set slightly wider than the manus tracks; digits are elongated and slender, and the fourth digit of the pes is the longest. Whereas the slender, long toes indicate a terrestrial form, the gait was more advanced than the sprawling gait typical of the most primitive tetrapods.

We document a speciation event between two species of Prunum (Marginellidae: Gastropoda) in Pliocene strata of the northern Dominican Republic. The ancestral species, P. coniforme, is widely distributed in the Mio-Pliocene of the Dominican Republic and Jamaica, and has a range of at least 11 m.y. The descendant species, P. christineladdae, is endemic to the northern Dominican Republic. The ancestral species persists after its descendant arises. The transition between species is marked by stratigraphic and morphologic intermediates, and occurs during an interval estimated to be between 73,000 and 275,000 years (representing 0.6-2.5 percent of the duration of the ancestral species). Although the transition takes more than a geologic instant, the overall pattern of morphologic change is best described by the model of punctuated equilibrium. The change between species apparently involved a habitat shift into deeper water, and occurred during accelerated deepening. All of the Neogene Dominican species of Prunum appear to have had depth-defined ranges.