Skull bones of Gosfordia truncata Woodward, 1891, from the Lower Triassic Hawkesbury Sandstone of New South Wales, Australia, are described for the first time. The skull roofing pattern suggests possible affinities between G. truncata and Paraceratodus germaini (Triassic, southwest Madagascar). A three-dimensional reconstruction of the skull of Ceratodus formosus Wade, 1935, based on the holotype, found in a Lower Triassic deposit at Brookvale in New South Wales, is included. This reconstruction indicates that this species is not closely related either to the recent Australian lungfish, Neoceratodus forsteri, or to the Triassic Ceratodus (Tellerodus) sturii from Nord Alpen in Austria, and it has no close affinities with G. truncata. A new genus, Ariguna, is therefore proposed to receive Ceratodus formosus Wade, 1935. Without associated tooth plate material, G. truncata and A. formosa cannot be defined more precisely.

Fossilized animal embryos from lower Cambrian rocks provide a rare opportunity to study the ontogeny and developmental biology of early animals during the Cambrian explosion. This paper reports possible animal embryos, along with sponge spicules, hyolithelminths, and linguliformean brachiopods, from the upper Shuijingtuo Formation limestone (Cambrian Stage 3) at Changyang, Hubei Province, South China. This limestone unit has carbonate carbon and oxygen isotopic compositions similar to the upper Shuijingtuo limestone in the Yangtze Gorges area. The Shuijingtuo embryo fossils were exposed by physical fracturing, extracted with acetic acid maceration, and observed in thin sections. They were examined using light microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopic elemental mapping, and micro-focus X-ray computed tomography. Most of them are poorly preserved, with a phosphatic envelope (interpreted as a chorion or fertilization envelope) surrounding sparitic calcite. In some specimens, a polygonal pattern is present on the surface, and these are interpreted as multicelled blastula embryos. In others, sets of grooves are present on the surface of a calcitic spheroidal structure, presumably representing the calcitic interior within the chorion; these grooves are superficially similar to annulations of Markuelia embryos, but their biological significance is unknown. Although their phylogenetic and taxonomic placement is largely unconstrained, the Shuijingtuo animal embryos indicate that chorions are taphonomically more robust and are selectively phosphatized. Embryos within the chorions, on the other hand, can be completely lost or entirely replaced by calcite, with only poorly preserved surficial structures. This style of preservation can be explained by a taphonomic switch from early phosphatization to later calcitization. This study illustrates the importance of combining physical fracturing with widely used acid digestion methods in the study of calcitized animal embryos, and it alludes to the possibility that many empty phosphatic vesicles recovered by acid digestion from Cambrian carbonates may be fossilized chorions.

Radiolaria have been recovered in acid residues from late Middle Cambrian strata in western Utah. Although the first Cambrian radiolaria were described by Nazarov (1973) from the Batenevskij Mountains of eastern Kazakhstan in the Soviet Union, radiolaria have not been reported from the Cambrian of North America. Except for the Kazakhstan specimens, the oldest known radiolaria are from the Lower Ordovician of western Spitsbergen (Fortey and Holdsworth, 1971). In North America only two accounts of Ordovician assemblages have been reported from southwestern Newfoundland and eastern Nevada (Bergström, 1974; Dunham and Murphy, 1976).

A recently discovered vertebrate fossil-bearing locality in the Fleming Formation of easternmost Texas has revealed a highly diverse fauna that contains a minimum of 44 early Miocene vertebrate taxa. At least 17 different species of lower vertebrates were recovered including five fish, two amphibians, one lizard, two snakes, at least five chelonians, and two crocodilians. A tiny boid that compares favorably with Anilioides nebraskensis is the first record in the Gulf Coastal Plain, and remains of a large aquatic turtle referred to the genus Dermatemys possibly represent its first fossil occurrence. Other rare genera represented include the largemouth bass Micropterus, possibly the snook Centropomus, and the crocodilian Gavialosuchus. In addition, temporal and spatial range extensions are recorded for Micropterus and Alligator olseni. These taxa, along with the mammalian component to be discussed elsewhere, document the rare preservation of a forested subtropical to tropical coastal lowland paleoenvironment and provide evidence to imply that separation into mid-continent and coastal plain paleobiogeographic provinces had not yet occurred.

A prominent anterior bulge on a ceratopsian dinosaur phalanx was examined for evidence of infection or stress (fatigue) fracture. The presence of a knife-slice type radiolucency, associated with periosteal reaction, was pathognomonic (diagnostic) for a stress fracture. Stress fractures have previously been recognized only in humans, racing greyhounds, and horses.

A collection of 6,151 bryozoan colonies (two cyclostome species from two families, and 73 cheilostome species from 30 families) from the leeward fringing reef of Bonaire, Netherlands Antilles, is largely, but not entirely, of Caribbean affinities, with some links to Indo-Pacific populations. The bryozoans from Bonaire show some relation to water depth at species and higher taxonomic levels, but these relations are not clear-cut. Many of the species are found through all or most of the 73 meter depth range sampled, but a few are limited to shallow water, and some to deeper water. At a higher taxonomic level, some families (e.g., Calloporidae, Bugulidae, Smittinidae) include wide depth-ranging species, shallow-water species, and deep-water species; this indicates some divergence between species and family-level depth distributions. Several calculated diversity indices show variable trends with increasing water depth, with at most only slight increases with depth. The bryozoans in this southern Caribbean reef assemblage do not show the well-defined depth zonation of corals. However, the recognition of deep- and shallow-water assemblages containing diagnostic species does show that cryptic reef-dwelling bryozoans have paleoecological utility as depth indicators in ancient reefs.

Microstructural and compositional data support the view that the skeletons of rugose corals consisted of (probably high-Mg) calcite, unlike the skeletons of scleractinian corals which are predominantly aragonitic. Total transformation of a late Permian rugose coral skeleton into neomorphic calcite and a significant trace element composition, however, show that aragonite was present in some Rugosa shortly prior to the extinction of this order. This finding sheds new light on the possible phylogenetic relationship between Rugosa and Scleractinia, which still possess a different mode of septal insertion and remain separated by an as yet coral-free interval in the Lower Triassic.

Sixty-five fossil brachyuran crabs, collected from rocks of the Orca Group, Tokun Formation, and Poul Creek Formation, have been assigned to six species, five of which were described previously. One of these, Pilumnoplax hannibalanus, is reassigned to Neopilumnoplax. Morphologic descriptions of Raninoides vaderensis, Eumorphocorystes naselensis, Portunites alaskensis, and Branchioplax washingtoniana are emended. Orbitoplax plafkeri n. gen. and sp. is described from the Poul Creek Formation on Wingham Island. The diagnosis of age for the Orca Group has been problematic. However, the well-preserved brachyurans, Branchioplax washingtoniana, Neopilumnoplax hannibalanus, and Raninoides vaderensis, provide corroborative evidence for an Eocene or older age for the rocks. Alaskan decapods include species common to the entire Pacific coast north of California, as well as species endemic to Alaska.

The new dragonfly family Austroperilestidae n. fam. based on Austroperilestes hunco n. gen. and sp. is erected from early Eocene of Patagonia (Argentina). Its phylogenetic relationships within the Zygoptera (sensu Bechly, 1996) are discussed. The new family seems to be related to Perilestidae, with a Neotropical and Afrotropical recent distribution.

New Mollusca from the shallow marine, highly fossiliferous Wangaloa Formation of southeastern Otago, South Island, New Zealand, are described. This paper reports three new species and one new genus: Leionucula palaioanaxea n. sp. of the Nuculidae, Pyropsis zinsmeisteri n. sp. of the Tudiclidae, and Wangacteon grebneffi n. gen. and sp. of the Acteonidae. These taxa represent new records in New Zealand of apparently endemic taxa. The molluscan fauna of the Wangaloa Formation is important in the understanding of Paleogene biogeography of the Southern Hemisphere and changes in faunal composition of the Cretaceous–Tertiary Gondwana Realm. Genus- and species-level endemism in the “Wangaloan” fauna is marked and is probably a reflection of “greater New Zealand” 's geographic and genetic isolation during the Paleocene. Although deposits containing early Paleogene Mollusca are generally rare in the Southern Hemisphere, comparisons of known Gondwana molluscan taxa and those of similar age in the Northern Hemisphere indicate that the Mollusca of the Wangaloa Formation have Early Paleocene affinities. Microfossil evidence, in addition, supports an Early Paleocene age for the fauna. However, an uppermost Cretaceous age is indicated for the basal part of the Wangaloa Formation stratigraphically below the shell beds, but the K–T boundary has yet to be located.

Little is known of the non-dinosaurian fauna from the Cretaceous (Maastrichtian) part of the North Horn Formation, despite its biogeographic importance. Herein we describe a new marsupial mammal from the unit, founded on an exceptionally complete specimen of a juvenile individual, and present new information on the incisor region of early marsupials, based on comparison with complete specimens from the early Paleocene of Bolivia. Alphadon eatoni, new species, is the smallest Lancian species of the genus, and departs from a presumed marsupial morphotype in having the second lower incisor enlarged. The species is, however, primitive in lacking a “staggered” pattern to the incisor series and in having a labial mandibular foramen, and in these respects it differs from Paleocene and later marsupials. Poor representation of other taxa precludes meaningful comparison to most other North American Cretaceous marsupials, although Eodelphis, thought to be distantly related, also has an enlarged i2. Although Alphadon is characterized by many primitive features, the relative development of the incisors is not what would be predicted in a morphological antecedent to later Marsupialia.

Remarkably well-preserved specimens of Marocella Geyer, 1986, from the Lower Cambrian Shackleton Limestone of Antarctica show that although affinity with chondrophorine cnidarians is improbable, its rigid caplike shell also is unlike that of any known mollusk. Association with sclerite-bearing taxa cannot be ruled out, but at present the phylogenetic affiliation of the genus remains equivocal.

Platycrinites is traditionally one of the more recognizable crinoids, a camerate crinoid with very few if any fixed brachials or interradials and a helically twisted column. Accordingly, many taxa have been assigned to this genus. With a better understanding of the Platycrinitidae, these characters actually unite the family Platycrinitidae rather than the genus. Further, use of different genus-diagnostic characters in Western Europe versus North America has resulted in a confused systematics for this important late Paleozoic family. Here, we objectively define genera within the Platycrinitidae and assign all species to either newly defined or newly named genera. A phylogenetic hypothesis, incorporating both parsimony-based character analysis and stratigraphic ranges, of the genera within the Platycrinitidae is presented.

With consideration of the type species, Platycrinites laevis Miller, 1821, Platycrinites sensu stricto is distinguished from Platycrinites sensu lato, which is used for species that cannot be assigned with confidence to any objectively defined genus. New genera are Artaocrinus n. gen., Collicrinus n. gen., Elegantocrinus n. gen., and Laticrinus n. gen.; and Exsulacrinus Bowsher and Strimple, 1986 is designated a junior synonym of Platycrinites s.s. Collicrinus shumardi n. gen. and sp., Laticrinus oweni n. gen. and sp., and Laticrinus wachsmuthi n. gen. and sp. are described; and Platycrinites formosus approximatus (Miller and Gurley, 1896a) is designated a junior synonym of Platycrinites formosus (Miller and Gurley, 1895a), which is reassigned here to Collicrinus n. gen. Platycrinites s.s. now includes 14 species and species-level taxa, and 76 species are assigned to Platycrinites s.l. Ten species are designated nomina dubia, as are taxa based solely on columnals or pluricolumnals. Two species are designated nomina nuda, and two are transferred to genera outside of the Platycrinitidae. In addition, twenty-seven species and four open-nomenclature taxa are each reassigned to a different genus.

Heterochrony is an important component of evolutionary change in the shell sculpture of turritelline gastropods from Paleocene and Eocene sediments of the Gulf and Atlantic Coastal Plains. A survey of heterochronic modes in these gastropods indicates that peramorphosis is dominant over paedomorphosis, a result counter to the pattern previously reported in gastropods and most other groups. Although lack of ontogenetic age data makes firm conclusions impossible at present, peramorphic patterns may have been produced by more than a single process. Possible explanations for the dominance of peramorphosis in the evolution of shell form in this group include a bigger role for intrinsic constraint in controlling shell form versus soft-part anatomy, selection for larger shell size, and the chance discovery of only peramorphosis in this study.

The poorly known type species of Acrotreta, A. subconica Kutorga, 1848 [=Spondylotreta faceta Gorjansky, 1969], is redescribed and a neotype selected from the lower Arenig (Billingen Stage, Oeland Series) Päite beds in the environs of St. Petersburg (Tosna river), Russia. Acrotreta is also the type of the lingulate brachiopod family Acrotretidae Schuchert, 1893, and order Acrotretida Kuhn, 1949. Four new species are described: A. korynevskii from the upper Tremadoc–lower Arenig, South Ural Mountains; A. tallinnensis from the upper Arenig (Volkhov Stage), Tallinn, northern Estonia; A. nobilis from the Llanvirn (Kunda Stage), Siljan district, Sweden; A. cooperi from the Llandeilo, Alabama, USA. Acrotreta has many features in common with Spondylotreta Cooper, 1956. The type species of the latter, S. concentrica Cooper, 1956, from the Llandeilo Pratt Ferry beds at Pratt Ferry, Alabama, is refigured.

Data from current research dealing with Jurassic ammonoids and stratigraphy of western North America are being stored in a computer file called AMMON using a data base management system. Each ammonite is described by up to 94 descriptors divided into the following six categories: taxonomy, quantitative morphology, qualitative morphology, stratigraphy, locality-catalogue information and general remarks. Data entry is facilitated by the use of a template on a video display terminal, the use of code numbers instead of full names and the bulk entry of hierarchic data. The computer can be used to speed fossil identification and retrieve geologic data by matching lists of descriptor states for a given specimen against those stored in the data bank. By interfacing with statistical analytical systems a ‘profile’ of a given taxon can be generated showing ranges of morphologic variation for any stage of ontogeny. Multivariate techniques are readily employed and subtle patterns of covariation more easily assessed. The data base may also be questioned to instantly generate taxonomic lists by zone, geographic area, lithostratigraphic unit, etc. (or any combination thereof) so that its research potential is considerable.

AMMON is a prototype meant to serve as a basis for discussion in developing a globally acceptable ammonoid data base. If code numbers for taxonomic, morphologic and stratigraphic data are standardized, information can be exchanged internationally using magnetic tapes and then decoded by the computer into any language. As data bases proliferate, they will inevitably make paleontological information more readily accessible to the specialist and non-specialist alike.

Even though ammonites are not very abundant in Patagonia, a large number of specimens were collected by geologists from the Empresa Nacional del Petroleo (ENAP), Chile, during the course of several years of field work in the Magallanes Basin. This study describes the ammonite family Kossmaticeratidae present in that collection, which is a typical element of most southern hemisphere Late Cretaceous assemblages. The species described include: Kossmaticeras (Kossmaticeras?) fasciculatum n. sp., K. (Karapadites) constrictus n. sp., K. (Natalites) cecioni n. sp., K. (Natalites) hauthali (Paulcke), K. (Natalites) sp., Neograhamites kiliani Spath, N. taylori Spath, Gunnarites elegans n. sp., G. bhavaniformis (Kilian and Reboul), Grossouvrites gemmatus (Huppe), and Maorites densicostatus (Kilian and Reboul).

The stratigraphic information on this fauna indicates that it is distributed in four assemblages. The oldest (assemblage A), possibly late Santonian to early Campanian in age, includes the species Kossmaticeras (Kossmaticeras?) fasciculatum, Neograhamites taylori, and possibly N. kiliani. This is followed by assemblage B (possibly middle to late Campanian), with K. (Karapadites) constrictus, K. (Karapadites) centinelaense (Blasco, Nullo, and Proserpio), K. (Natalites) hauthali, K. (Natalites) cecioni, Neograhamites morenoi Riccardi, N. taylori, N. kiliani, K. (Natalites) sp., Gunnarites elegans, G. bhavaniformis, and possibly Pseudokossmaticeras paulckei Collignon. The third assemblage (C), possibly late Campanian to early Maastrichtian in age, contains G. elegans, G. bhavaniformis, Grossouvrites gemmatus, and K. (Natalites) hauthali. The youngest assemblage (D) is possibly late Maastrichtian in age and is composed of the species Maorites densicostatus and Grossouvrites gemmatus.

The Trinity Division exposures at Junction, Kimble County, Texas, yield a rich charophyte flora dominated by clavatoraceans. The presence of Atopochara trivolvis ssp. trivolvis (Peck, 1938) Grambast, 1968, and Clypeator corrugatus (Peck, 1941) Grambast, 1962, indicates an Aptian age for these strata and makes them the continental equivalent of the Lower Glen Rose. Atopochara trivolvis, whose type-material was recovered from the Trinity in a deep well in southern Texas, is known from numerous freshwater to oligohaline lakes from the Mesogean area in Europe and North Africa as well as from Cretaceous oil-bearing basins in China. Charophytes are clear indicators of supratidal environments and the abundant remains at Junction suggest a positive structural feature in this part of central Texas that might have been either an island or directly connected to the Llano Uplift.

This study represents a preliminary analysis of variation in size and shape in a large and diverse molluscan clade, the Strombina group, over the past 20 million years. Restored height and width were measured on 5,099 individuals of 72 species and 5 genera. Size was estimated by adding height and width, and shape was estimated by dividing height by width. Patterns of variation were analyzed quantitatively among species, subgenera, and genera using univariate statistical tests comparing means and variances and linear regression.

Results of univariate tests show that both shape and size vary among species within subgenera (the specific level) and among genera (the generic level). However, only shape varies among subgenera within genera (the subgeneric level). Regression analyses for each species show that the relationship between height and width is linear, indicating that growth is never allometric with respect to these characters. Because of this nonallometric growth, rates of shape relative to size change can never vary, imposing a severe constraint on shape change and, in turn, shape evolution. Regression models for species within subgenera have equal slopes but differ slightly in intercept. Subgeneric models differ more in intercept. Generic level models differ in slope. These results suggest that formation of species within subgenera primarily involves extension or contraction of trajectories between height and width within species (=static vectors), resulting in size change without shape change. Shape change is more important in the evolution of higher categories.

To examine overall morphologic change in the clade through time, mean sizes and shapes of species were analyzed using nonparametric statistics. Only a slight tendency exists within the clade for increase in species size, and this tendency is best expressed within two species-rich subgenera having long stratigraphic ranges. No directional trends exist for change in species shape. No relationship is found between species size and probability of speciation or extinction, or between species size and species duration, thus negating the role of species selection. Nevertheless, species are smaller in size in the northern Caribbean, a region characterized by extreme fluctuations in temperature. Larger species occurred only after a taxonomic radiation in the eastern Pacific, a more restricted region possibly characterized by reduced environmental disturbance. During this radiation, normal patterns of morphologic change associated with speciation appear to have been disrupted.

The parautochthonous Anisian and Ladinian rocks of the New Pass Range previously referred to as the Augusta Mountain Formation have a unique, endemic assemblage of pteriomorphian bivalves with Triassic Northern Hemisphere biogeographic relationships, especially to the Carnian cratonal faunas of northeastern British Columbia as well as to Ladinian faunas of the Shoshone Mountains and the Gillis Range. A new suborder Prospondyloidina is described, as well as three new genera, Promysidiella, Loxochlamys, and Nevadapecten, a new subgenus, Gervillaria (Baryvellia), and 17 new species either named or referred to by letters: Promysidiella planirecta, P. desatoyensis, Bositra favretensis, Enteropleura species a, Gervillaria (Baryvellia) ponderosa, Atrina sinuata, Antiquilima ladinica, Palaeolima newpassensis, Plagiostoma acutum, Leptochondria shoshonensis, Asoella? species a, b, and c, Oxytoma (Oxytoma) grantsvillensis, Pleuronectites newelli, Loxochlamys corallina, and Nevadapecten lynnae. Promysidiella aff. otiosa is a new combination for Mytilus otiosus McLearn; Mysidiella newtonae n. sp., Norian, Wallowa terrane, is based on Krumbeckiella cf. timorensis (Krumbeck) of Newton, 1987. Triassic “Posidonia” is placed in Bositra de Gregorio, 1886, regarded as a senior synonym of Peribositria Kurushin and Trushchelev, 1989. The morphological and stratigraphic sequence Bositra-Enteropleura-Daonella-Aparimella-Halobia is rooted in Paleozoic Caneyella and Posidonia and indicates declining dependence on and eventual loss of byssal attachment as well as a possible shift from low to high dispersal ability (between Bositra and Enteropleura). There is no evidence for trans-Panthalassan dispersal of bivalves in low latitudes within the interval of Ladinian coral beds. So-called Tethyan and Muschelkalk species are endemics in slowly evolving genera or are phylogenetically convergent on west Tethyan species.