Abundant “hydrozoans” are important frame-building and accessory organisms in Middle and Upper Permian reefs of southern China, particularly in western Hubei, eastern Sichuan, eastern Yunnan, and northwestern Guangxi. The new genera Radiotrabeculopora, Lichuanopora, and Pseudopalaeoaplysina are described, as are the new species Disjectopora beipeiensis, D. irregulara, Radiotrabeculopora xiangoboensis, R. maokoui, R. elegans, R. reticulata, R. astrorhiza, Balatonia robusta, Lichuanopora bancaoensis, L.(?) regulara, Pseudopalaeoaplysina sinensis, and P. major. The assemblage represents one of the most diverse upper Paleozoic “hydrozoan” assemblages known.

Recognition of discrete taxa is an enduring problem in the biological sciences, especially for taxonomists who work with groups that display a great degree of homeomorphy at low taxonomic levels. Selection of the type and number of characters used to make taxonomic distinctions is important because it reflects taxonomic concepts for a group as a whole. Often the validity of characters used to develop classifications is not documented and resulting classifications are therefore suspect. However, classifications can be tested for their objectivity with numerical analysis and characters can be evaluated for their relative value for making taxonomic splits by a variety of statistical techniques. In addition, evaluation of the distribution of character states can lead to insights into evolutionary histories of any group. This study provides such an analysis.

Fenestrate cryptostome Bryozoa are abundant and diverse in many upper Paleozoic rocks, and are therefore potentially highly useful for a variety of paleontologic studies. However, study of fenestrates is hampered by necessary complex preparation techniques and problems encountered with homeomorphy. In addition, inconsistent applications of inadequate methodologies have contributed to an unsatisfactory taxonomy. Results from cluster and discriminant analyses demonstrate that fenestrate species can be objectively recognized. Species distinctions are most clear when all available characters are used, although some characters are more diagnostic than others.

Results from cluster and discriminant analyses suggest that fenestrate genera represent major evolutionary shifts associated with the development of key character(s) that allowed entry into new adaptive zones. Key characters allow for an oligothetic classification of genera, which is not merely an artifact created to simplify taxonomic analysis. Diversification of species within adaptive zones resulted in a natural hierarchy of genus-level and species-level characters. Iterative evolution at the species level within separate adaptive zones resulted in a great deal of homeomorphy.

Morphometric analysis provides insights into several aspects of the paleobiology of this traditionally problematic group. Similar comprehensive studies may prove equally productive for other groups.

The atlas-axis complex in the Early Permian diadectomorph Diadectes is shown to be similar to those of a variety of primitive amniotes. Diadectes does not possess elements in addition to the standard complement seen in advanced batrachosaurs and primitive amniotes as previously thought. Characteristics of the complex include: paired, well-developed proatlases and atlantal neural arches, lack of atlantal neural spines, an extremely robust atlantal intercentrum, fusion of the atlantal pleurocentrum and axial intercentrum, a large anterior projection of the axial intercentrum, exclusion of the atlantal pleurocentrum from ventral exposure, fusion of axial neural arch and pleurocentrum, and a robustly developed axial neural spine. An analysis of the transformations of the atlas-axis complex in advanced anthracosaurs and primitive amniotes indicates that many of the characteristics of the complex previously thought to be definitive of amniotes or reptiles appear to be conditions common to Diadectes plus Amniota.

Adult intercolony fusion occurs in Paleofavosites capax (Billings) and P. asper (d'Orbigny) in the Silurian of Anticosti Island. This represents the first documented example of allogeneic fusion seen in tabulate corals. The occurrence of allogeneic fusion and non-fusion and the documentation of agonistic behavior in the same species attest to the presence of some degree of allorecognition specificity, now well established for modern corals, already in these Silurian corals. The implication is that the evolution of allorecognition systems, probably by polymorphism at allorecognition loci, was already well established 400 million years ago in corals. Banding, probably seasonal, appears to be more likely environmentally than genetically controlled.

The discovery of beautifully preserved specimens of a macruran decapod provides the basis for redescription of Hoploparia antarctica Wilckens, a hitherto poorly known species from the Campanian–Maastrichtian of the Austral basin of Southern Patagonia. Analyses of the associated molluscan fauna, trace fossils, and sedimentary structures indicate that the material is mostly preserved in calcareous sandstones and coquinas deposited in shallow, well-oxygenated environments. These new findings of H. antarctica in Maastrichtian deposits of the Lefipán Formation of Chubut expand the geographic distribution of the species and add a new element for the comparison of the Lefipán fauna with that of the austral Wedellian Province.

The gastropod Drepanochilus pervetus (Stanton) and the bivalve Cytrodaria rutupiensis (Morris) occur in the Mount Moore Formation at Strathcona Fiord, west-central Ellesmere Island, northern Canada. They are the first marine mollusks identified from the Eureka Sound Group of the Canadian arctic islands. These mollusks correlate with Paleocene faunas of the Cannonball Formation of North Dakota and South Dakota, the Prince Creek Formation of northern Alaska, the Barentsburg Formation of Svalbard, and the Thanet and Oldhaven Formations of southeastern England. These occurrences imply that the earliest Tertiary Arctic Ocean molluscan fauna was compositionally distinct from coeval faunas of the northern Atlantic Ocean.

Worthenopora is a Mississippian cryptostome bryozoan genus with certain characteristics that so closely resemble those of some cheilostomes (Jurassic–Recent) that previous bryozoan experts speculated whether Worthenopora should be assigned to the order Cheilostomata. This raises the question of possible affinities between cryptostomes (class Stenolaemata) and cheilostomes (class Gymnolaemata). Based on wall structure, growth sequence, zooecial shape, and secondary structures such as stylets, Worthenopora is here shown to be a stenolaemate, assignable to the suborder Ptilodictyina with other bifoliate cryptostomes. Although the exterior appearance of Worthenopora superficially resembles some cheilostomes, it represents rather limited divergence from more typical bifoliate growth patterns. Additionally, presence of characteristics such as elongate zooecia with thin exozones, cuticular medial plane, and distinctive exterior ridges justifies retention of the monogeneric family Worthenoporidae. Three species (W. spatulata, W. spinosa, and W. valmeyerensis), known only from North America and primarily restricted to the Illinois Basin, are recognized. Analysis of apertural spacing in these species suggests a trade-off between feeding efficiency and occupation of water-column space. Worthenopora valmeyerensis is considered a hypermorphic derivative of W. spinosa.

The Cenomanian ammonites of the Helvetic Domain (French-Swiss Western Alps) are revised and illustrated for the first time since the middle of the Nineteenth Century. The faunas occur in remarkable condensed hemipelagic glauconite-rich biomicrites that also contain planktic foraminifera and small stromatolites. Thirty-three ammonite species referred to 15 genera are described; the assemblage extends from the lower part of the Lower Cenomanian Mantelliceras mantelli Zone (Neostlingoceras carcitanense Subzone) to the lower part of the Middle Cenomanian Acanthoceras rhotomagense Zone (Turrilites costatus Subzone). The assemblage comprises 57 percent trachyostracous forms, 41 percent heteromorphs of the standard N.W. European sequence, and 2 percent leiostracous forms, which inhabited an external shelf biome. The biogeographic affinity of this fauna is essentially cosmopolitan (69 percent), but 31 percent of the specimens belong to the European Boreal biota, with no Tethyan taxa.

A revision of the Silurian paulinitid scolecodont taxa from the Power Glen Formation of the Medina Group at Niagara Gorge relies on multi-element taxonomy to place the five genera and ten species of Eller (1940) into just two species: Kettnerites invisibilis (Eller, 1940) and ?K. plenidens (Eller, 1940). The generic name Nereidavus should not be used for paulinitids; the type specimen of Nereidavus has been lost, and indications are that it was probably not a paulinitid.

Lyrischapa Aldrich (1911), originally described from the Eocene of North America, is represented in the Old World Tethyan paleobiotic province by three species that previously have been referred to other genera: L. haimei (d'Archiac), from the late Paleocene or early Eocene upper Ranikot Formation of Pakistan; L. sismondai (d'Archiac), from the upper Ranikot Formation and the late Paleocene Hangu Shales of Pakistan; and L. soudanense (Douvillé), from the late Paleocene Kalambaina Formation in the Republic of Niger. A fourth unnamed species of Lyrischapa may be represented by an internal mold from the middle Eocene Khirtar Formation of Pakistan. Lyrischapa probably originated within the ancient Tethys seaway between Eurasia and the Gondwana continents of Africa and southern India because its oldest known occurrence (late Paleocene) and closest relatives (Indovoluta Eames, 1952; Gosavia Stoliczka, 1865, 1868; possibly also Diconomorpha Wenz, 1943) are in that region. It has no apparent ancestor among described American Paleogene or Cretaceous Volutidae. Because its large protoconch suggests that it lacked a teleplanic larval stage, the trans-Atlantic migration of Lyrischapa to the New World probably resulted from chance dispersal, either by rafting of egg masses attached to floating plant debris or by drift of floating egg capsules.

The problematical rodent genus Cedromus Wilson, previously only known from the Orellan of the Great Plains, has been considered a sciurid by some authors and an aplodontid by others. An excellent collection of complete skulls with associated mandibles from Converse County, Wyoming, has provided evidence that this genus is a sciurid but that it represents a new subfamily distinguished from all other sciurids by a unique zygomasseteric structure that closely approaches myomorphy. A second genus, Oligospermophilus Korth, also from the Orellan of the Great Plains, is allocated to this subfamily.

Additional and more complete cranial material of the primitive aplodontid Prosciurus indicates that sciurids and aplodontids share a common ancestry and should be included together at least within the same suborder Sciuromorpha.

Three species of Cedromus are recognized, C. wardi Wilson, C. wilsoni n. sp., and Cedromus sp.; the latter extends the known temporal range of the genus into the Whitneyan.

Bivalves comprise a major component of the faunules of the Mississippian Mauch Chunk Group in northern West Virginia and southwestern Pennsylvania. Twenty-eight species representing 22 genera have been recognized. Of these, three new species are proposed—Limipecten greerensis, Streblochondria tiltoni, and Prothyris (Prothyris) acuticarinata.

In the South Nahanni River area of the District of Mackenzie, the Middle Ordovician Sunblood Formation comprises mainly limestones and dolostones of intertidal and shallow-subtidal origin, as indicated by the presence of desiccation polygons, fenestral fabric, and oncolites. Faunas of well-preserved, silicified trilobites from a low-diversity, nearshore, Bathyurus-dominated biofacies are compositionally distinct from faunas in correlative strata around North America that represent different shelf to upperslope biofacies. A temporal biostratigraphy applicable to nearshore biofacies through much of the Whiterockian Series consists of five zones, in ascending order: Bathyurus mackenziensis, B. sunbloodensis, B. margareti, B. nevadensis, and B. granulosus. Twenty-six species are assigned to 18 genera, of which Ludvigsenella is new. Three new species of Bathyurus are B. mackenziensis, B. sunbloodensis, and B. margareti.

Phylogenetic parsimony analysis forms a basis for classification of the Siegenian–Eifelian “Malvinella group,” a monophyletic taxon within the “Metacryphaeus group” of the family Calmoniidae. Fifty-one exoskeletal characters for Metacryphaeus Reed and 12 taxa of the “Malvinella group” yield a shortest length cladogram with a consistency index of 0.51. A classification based on retrieving the structure of this cladogram recognizes six genera: Malvinella Wolfart, Vogesina Wolfart, Palpebrops n. gen. (type P. donegalensis n. sp.), the sister taxa Parabouleia Eldredge and Bouleia Kozlowski, and Plesiomalvinella n. gen. [type P. pujravii (Wolfart)]. Palpebrops is more closely related to Vogesina than to Malvinella; Amazonian species are nested within this group as sister taxa to Andean or Amazon/Andean clades. Bolivian Belén Formation Malvinella buddeae n. sp. is an allopatric species distinct from Icla Formation M. haugi (Kozlowski). “Metacryphaeus” of recent revisions is a paraphyletic grade group including primitive species of the “Malvinella group.” Metacryphaeus australis (Clarke), M. tuberculatus (Kozlowski), and M. caffer (Salter) are endemic to the Paraná Basin, Andean Bolivia–Parnaíba Basin, and South Africa, respectively.

Naticid gastropods of the Chesapeake Group of Maryland, like extant naticids, apparently were cannibalistic. This cannibalism did not result from the absence of bivalve prey or from the ineptitude of the predator, as some previous authors have suggested. Instead, predation on Chesapeake Group naticids was a predictable result of prey selection to maximize energy gain per foraging time.

This study examines predation on Lunatia heros (530 specimens) and Polinices duplicatus (340 specimens) from the St. Marys Formation of the Chesapeake Group. Predation on naticids displayed the same characteristics as predation on bivalve prey, including selectivity of prey size and drillhole site. The two naticid species were differentially attacked, based on their relative cost-benefit ratios and escape sizes. Cannibalism is not anomalous; it is the expected result of selective predation, and is inhibited primarily by the high mobility of naticid prey.

Nine assemblages of conodont elements have been found on bedding surfaces of the “Wolfcamp Shale’ from the Midland Basin, Texas. Four of these assemblages have Pa elements assigned to Sweetognathus cf. S. inornatus. The assemblages are classified taphonomically as apparatus (remains or partial remains of a single individual) or coprolitic associations. The two apparatus assemblages indicate that Sweetognathus cf. S. inornatus possessed a seximembrate apparatus comprised of Pa, Pb, M, Sa, Sb, and Sc elements. Five of the seven coprolitic associations contain numerous elements (50–100) and/or multiple pairs of Pa elements representing the presumably ingested remains of two or more conodonts.

The “Wolfcamp Shale’ assemblages are significant because 1) they confirm the polygnathacean affinity of the family Sweetognathidae, 2) they represent the youngest polygnathacean assemblages currently known, and 3) they permit comparison of multielement Sweetognathus with homologous elements of coeval genera such as Hindeodus, Adetognathus, Streptognathodus, and Neostreptognathodus.

This paper demonstrates, for the first time, the existence of an inner partition (limen) in females of Kloedenella Ulrich and Bassler, 1908, and the presence of a juvenile carapace in the brood chamber of Poloniella tertia Kroemmelbein, 1953. These facts indicate that the Kloedenellidae Ulrich and Bassler, 1908, and the living platycopes are closely related. Thin sections of female carapaces in kloedenellids, some cytherellids and a geisinid-like form, indicate that their posteriorly inflated valve walls are only half as thick as the remaining parts. This suggests that the feature developed in different lineages and had a pure adaptable character. A historical and critical survey of the kloedenellid literature is included. The latter involves a discussion of phylogenetic relationships between this group and other non-myodocopide ostracodes. In light of new facts and data reported earlier, revised diagnoses for the Kloedenellidae and Paleozoic Cytherellidae Sars, 1866, are presented.

Isolated teeth and post-cranial elements of fossil vertebrates were recovered from sand and gravel pits in valley fill and terrace deposits along the Nueces River in San Patricio and Nueces Counties, Texas. A log from the valley fill deposit has been radiocarbon dated at 13,230 ± 110 BP. The fauna is mixed and comprises typical late Pleistocene taxa and relatively abundant remains of early Pliocene (latest Hemphillian) horses. The latter group includes Astrohippus albidens (Mooser), Nannippus spp., Neohipparion eurystyle (Cope), and a derived species of either Calippus or Pseudhipparion. Many of these specimens show little or no evidence of abrasion, in spite of the fact that they may have been transported at least 12–25 km. The source beds for these early Pliocene horses are unknown, but the fossils were probably eroded from older, updip sediments of the upper Goliad Formation during a low stand of sea level at the end of the Pleistocene and deposited during the late Wisconsinan.

A new genus, Novoameura, is erected with the type species Anisopyge mckeei Cisne. Delaria macclintocki Cisne from the Kaibab Formation of Arizona is herein regarded as a junior synonym of Delaria sevilloidia (Chamberlain), which was originally described from the Phosphoria Formation of Wyoming. The Leonardian (Permian) San Andres Formation of the Sacramento Mountains, central New Mexico, contains trilobite species known both from the Kaibab Formation of Arizona and the Phosphoria Formation of Wyoming, but lacks trilobite species known from the nearby Permian of West Texas.