Endothyroid foraminifers are common in most marine Pennsylvanian units in the Appalachian Basin. The genera Planoendothyra Reitlinger, 1959, and Endothyranella Galloway and Harlton, 1930, are the dominant taxa. Scarce Endothyra Phillips, 1846, are restricted below the Desmoinesian. The greatest change in stratigraphic distribution of taxa occurs at the Atokan-Desmoinesian boundary.

Sixteen taxa are recognized. Five new species are proposed, including Planoendothyra orbiculata, P.? associata, Endothyranella kentuckyensis, E. inflata, and E. intermissa. Most taxa are assigned previously described American species using a cf. designation. Description and thin section illustration provide a basis for nomenclatural acceptance of these taxa.

Bryozoans are an important part of the benthic marine fauna in a wide variety of modern environments and are found in rock forming abundance in a number of settings throughout much of the Phanerozoic. Bryozoologists and nonspecialists have grouped taxa into colonial growth forms (e.g., erect fenestrates or encrusting sheets), both to simplify analyses and because correlations exist between some colony growth forms and the environmental conditions in which the organism lived. These correlations allow for the possibility of paleoenvironmental analyses based on skeletons alone. Existing bryozoan colonial growth form classifications do not, however, fully exploit the ecological information present in colony form.

A new scheme is proposed here (Analytical Bryozoan Growth Habit Classification), which provides a list of colony-level morphological characteristics for bryozoan growth habits. This differs from previous approaches to bryozoan growth form analysis in that it is a classification of growth habit characteristics rather than a classification of morphological groups as such. The classification is based on eleven character classes, which describe the orientation of the colony and its occupation of, and placement in space. The overall colony shape is described based on the arrangement of modules in colonial growth. This classification provides a common ground for systematic comparison of character states among varied bryozoan growth habits. This approach allows for the evaluation of correlations among observed morphological character states and specific environmental conditions in which they develop. In addition, these growth habit characters can be used to recognize, characterize, evaluate, and apply more traditional growth form groups in broader studies.

The genera Lissopleura, Sphaerirhynchia, Pectorhyncha, Yanishewskiella, and Terebratuloidea have been investigated to elucidate their internal features and taxonomic relationships. Specimens of the type species of these genera were sectioned. Lissopleura remains slightly enigmatic in that the holotype of Lissopleura aequivalvis is thinner and has a less pronounced fold than most specimens in the collection, including the one sectioned by us. The holotype is probably immature and is within the range of variation of specimens from the type area. The internal features lead us to assign Lissopleura to the Trigonirhynchiidae. Sphaerirhynchia wilsoni has a short septalium without a cover plate and other features that place it in the Hebetoechiidae. Pectorhyncha obtusiplicata has a very thick shell and a septalium filled by a large, bilobed cardinal process. The genus has several features similar to Obturamentella, and is assigned to the Obturamentellidae. Yanishewskiella angulata, which is retained within the Tetracameridae, has a spondylium with lateral buttresses, and a septalium into which the medium septum projects. Terebratuloidea davidsoni has small dental plates, and is assigned to the Allorhynchidae.

Ribbing became an increasingly common feature of pentamerid shells, especially the family Stricklandiidae, during the later Llandovery (Early Silurian). The thin shells of stricklandiids from the Llandovery (Aeronian-Telychian) equatorial carbonate rampshelf of Anticosti Island reveal at least three ribbing designs in various genera; 1) radially arranged ribs, e.g., Costistricklandia; 2) divergent, chevron-like ribs, e.g., Ehlersella; and 3) diagonally criss-cross, mutually intersecting divaricate ribs, as in Kulumbella and Microcardinalia (Chiastodoca) new subgenus. Weakly divaricate species previously assigned to Kulumbella, Stricklandia or Microcardinalia from Anticosti Island, South China and the Baltic region, are assigned to the new subgenus Chiastodoca (type Stricklandinia salterii Billings, 1868), and they are suggested to have evolved their divaricate ribbing from smooth forms, independently from the earlier genus Kulumbella, in the same sense that radial or divergent ribbing was developed separately in a number of pentamerid and stricklandiid lineages in the late Llandovery and Wenlock. In Anticosti, the divaricate genus Kulumbella, originally described from Siberia, appeared, without a known ancestral form, in the Anticosti Basin (as K. xacta n.sp.), and became extinct equally suddenly in the upper part of the Gun River Formation (mid-Aeronian). This sudden arrival of immigrant taxa, originally appearing earlier in other areas, is matched in other brachiopod groups and corals in the Anticosti section. Weakly divaricate ribbing in Chiastodoca is characteristic of the early Telychian (Ferrum Member, Jupiter Formation), and radial ribbing is typical of the late Telychian genus Costistricklandia (Pavillon Member, Jupiter Formation).

A new genus, Geniculigypa, and a new subfamily, the Geniculigypinae, are established. Both taxa are monotypic and have as their type species, Sieberella newtonensis Imbrie, 1959, from the Newton Creek Limestone (early Givetian) of Michigan. This species dramatically differs from all other known gypiduloid species in its possession of a prominent geniculation in both valves and by its radially grooved micro-ornament.

A review of the Late Ordovician, chiefly mid-Ashgillian, to Early Silurian, Llandoverian, pentameroidean brachiopods, the Virgianidae, permits them to be assigned to three subfamilies (Virgianinae [10 genera assigned], Mariannaellinae [5 genera assigned], Pleurodiinae [2 genera assigned]). Diagnoses are presented for each subfamily, with comments on diagnostic characters for each genus and species. All the genera occur in what are interpreted to have been relatively low latitude, warm water environments in Arctic North America, northern Europe, northern Asia, central Asia and South China; the presence of Australian Ordovician virgianids is uncertain at this time. The mid-Ashgillian pentameroid adaptive radiation was followed by latest Ordovician mass extinction, subsequently surviving recovery and radiation in the middle-Late Llandovery. Silurian radiations convergently mimicked the Ordovician event in many respects.

In the Recent biota, species of the hipponicid gastropod genus Sabia that excavate characteristic pits on the outer surfaces of shells of reef-dwelling gastropods and hermit crabs occur only in the tropical Indo-West Pacific region and in adjacent warm-temperate parts of Japan and Australia. I report the discovery of Sabia pits in reef-associated gastropod shells from the Cercado (late Miocene) and Gurabo (early Pliocene) Formations of the Dominican Republic. The likely culprit was Hipponix otiosa Pilsbry and Johnson, 1917, a species here reassigned to Sabia Gray, 1840. Pliocene extinction, which was far more severe in the Caribbean and elsewhere in the western Atlantic than in the Indo-West Pacific, selectively eliminated Sabia and its commensalism from Atlantic reef ecosystems. This case is one of several examples indicating the vulnerability of specialized associations to extinction-causing disturbances.

A third known specimen of the ammonite Rhaeboceras burkholderi Cobban, 1987, has been discovered in the upper part of the Pierre Shale of early Maastrichtian age (Late Cretaceous) Baculites eliasi zone of Dawson County, Montana. This finding extends both the geographical and stratigraphic ranges of the species. In addition, R. cedarense new species is described from the Baculites baculus/grandis zone of the same region, which extends the stratigraphic range of the genus as currently recognized. The new species is a small form of Rhaeboceras that appears to be closely related to and probably descended from R. burkholderi.

Hadoprion cervicornis (Hinde, 1879) from the Upper Ordovician and Lower Silurian (Cincinnatian to Medinian) replaces four generic and eight specific names: Arabellites cervicornis, A. aciculatus, Oenonites acinaces, Ildraites horridus, I. laeohorridus, I. cervicornis, Nereidavus hamus, and N. alatus. This example illustrates the advantages of a nomenclature in accordance with the ICZN. The authors reject the use of parataxonomy for fossil jawed polychaetes.

Leperditiocope ostracodes identified as Sollenella? sp. were discovered in the Gilboa Formation (upper Givetian, uppermost Middle Devonian) within the continental Catskill Magnafacies of New York State. The deposits in which the ostracodes were found are meandering-fluvial facies that were part of a vast alluvial plain that sloped westward from the eroding Acadian Mountains. Hence, ostracodes colonized freshwater habitats earlier than heretofore thought. It has been widely accepted that, until now, the oldest known unequivocal occurrences of freshwater ostracodes are of Late Carboniferous age. This new discovery means that the first colonization of freshwater habitats by Ostracoda occurred approximately 60 million years earlier than previously known.

Pupae of the nonbiting midge Chaoborus are reported from the middle Eocene (Claibornian) Tallahatta Formation in Benton County, Mississippi. These pupae are placed within the genus Chaoborus because the shape of the respiratory organs, length of the abdomen, and shape of the anal paddles closely resemble other species of this extant genus. This occurrence represents the oldest record of Chaoborus pupae and the first record of fossil Chaoborus from North America. The flora and fauna found associated with the fossil pupae along with the known habitats of extant Chaoborus pupae indicate a lentic environment. This interpretation corresponds to the depositional environment of similar Eocene-aged clay deposits in western Tennessee.

Feminization of adult male xanthid crabs, Tumidocarcinus giganteus Glaessner, from the Miocene of New Zealand, represents the first notice of the phenomenon in the fossil record. Marked broadening of the abdomen of adult males, to assume a form much like that of mature females and limitation in the size of the major claw likely result from parasitic castration by rhizocephalan, probably kentrogonid, barnacles. A sexually aberrant dakoticancrid, Dakoticancer overanus Rathbun, from the Late Cretaceous of South Dakota (Bishop, 1983) may extend this coevolutionary relationship between parasitic barnacles and decapod crustaceans into the Mesozoic.

A stepwise approach is employed to determine the phylogeny of the initial crinoid radiation during the Arenig and Llanvirn series of the Ordovician. Parsimony-based character analysis is completed first on Arenig crinoids and then for Arenig and Llanvirn crinoids combined.

The topology from well-resolved trees of this early crinoid radiation indicates that the Crinoidea should be subdivided into six subclasses. A new subclass and new order, Aethocrinea and Aethocrinida, respectively, are proposed for crinoids with four circlets of plates in the aboral cup: lintels, infrabasals, basals, and radials. This aboral cup construction is best displayed by Aethocrinus, one of the oldest known crinoids (?Tremadoc-Arenig). However, this primitive aboral cup construction is also present in two Llanvirn crinoids, Perittocrinus and Tetracionocrinus. The Aethocrinea was a small, short-lived radiation of crinoids with this design that was different from those of other crinoids. Two families in the Aethocrinida are the Aethocrinidae, which includes Aethocrinus, and the Perittocrinidae, which includes Perittocrinus and Tetracionocrinus. In addition to the Aethocrinea, the following crinoid subclasses are recognized based on character analyses of these earliest crinoids: Cladida, Camerata, Disparida, Flexibilia, and Articulata.

Nacocrinus elliotti new genus, new species, is reported from the beta member of the Naco Formation (Pennsylvanian, Desmoinesian) at the Kohl Ranch locality in central Arizona. This is the first pachylocrinid reported from the Naco Formation.

An asteroid fauna is described from the Albian (Cretaceous) interval of the Washita Group of central Texas. New genera and species are Alkaidia sumralli, (Benthopectinidae), Capellia mauricei (Goniasteridae), and Betelgeusia reidi (Radiasteridae). Additional new genera are Fomalhautia (Goniasteridae), and Denebia and Altairia (Ophidiasteridae). Crateraster texensis (Goniasteridae), new combination, is similar to the European type species, C. quinqueloba. An unnamed species of Crateraster and an unassigned goniasterid are also present. All Washita genera are extinct, but all belong to extant families. The fauna is largely distinct from that of the somewhat younger European Cretaceous chalk.

The Radiasteridae (e.g., Betelgeusia) is inferred to hold a basal position in the Paxillosida; Betelgeusia extends the range of the family back to the Cretaceous, closer to the diversification of the living asteroid orders. Asteroids capable of burying themselves in sediment (and only self-buriers) share some form of channelization for the passage of water currents between the primary ossicles of the body surface. Channels in Betelgeusia indicate semi-infaunal habits similar to those of living Astropecten and Luidia. Betelgeusia represents the third semi-infaunal paxillosidan family now known from the Cretaceous, although none are known from older rocks, suggesting a broadening of the asteroid adaptive zone during the Cretaceous. The Goniasteridae, Radiasteridae, and Benthopectinidae are less important in shelf settings today than they appear to have been during Washita deposition, whereas the Astropectinidae, Luidiidae, and the Echinasteridae are absent from the Washita although they are common today in similar settings.

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.

A new genus and three new species of the microchiropteran family Mystacinidae are described from Miocene freshwater limestones in northern Australia. The type species, Icarops breviceps new genus and species, is from the middle Miocene Bullock Creek deposit, Northern Territory; I. aenae new species and I. paradox new species are from the slightly older (early Miocene) Wayne's Wok and Neville's Garden Sites at Riversleigh, northwestern Queensland. Fossil mystacinids are rare in each deposit and represented so far only by lower teeth and dentary fragments. They are characterized by a suite of apomorphies shared only with Quaternary mystacinids endemic to New Zealand. The family Mystacinidae has no pre-Pleistocene record and its relationships to other groups of bats remain unclear. Possible sister-groups include South American noctilionoids and the cosmopolitan molossoids and/or vespertilionoids. The presence of plesiomorphic mystacinids in the Australian Tertiary suggests an Australian origin for the family.

Although relatively numerous accounts of late Tertiary canids have been reported from the western United States, records from Mexico are scarce. The three genera and species described and discussed in this paper come from Hemphillian and Blancan age deposits located in the state of Guanajuato, Mexico. All specimens were collected within a stratigraphic context. One taxon, Borophagus diversidens, was recovered from Blancan age deposits, while both Osteoborus cyonoides and a new species of Canis, C. ferox, came from deposits of Hemphillian age. This new species of Canis appears to be directly ancestral to the extinct C. lepophagus, long considered the forerunner of the modern coyote, C. latrans. The new Mexican canid also appears to be the earliest true Canis yet reported.

The discovery of a fish bone layer immediately overlying the K-T iridium anomaly on Seymour Island, Antarctic Peninsula, which may represent the first documented mass kill associated with the impact event, together with new faunal data across the boundary has provided new insight into events at the end of the Cretaceous. The utilization of a geographical approach and a new graphical representation of range data has revealed that events at the end of the Cretaceous were not instantaneous, but occurred over a finite period of time. Although the fish bone layer may contain victims of the impact event, the absence of ammonites in either the iridiumbearing layer or the overlying fish layer suggests that the extinction event at the end of the Cretaceous was the culmination of several processes beginning in the late Campanian. The impact was the proverbial “straw that broke the camel's back,” leading to the extinction of many others forms of life that might have survived the period of global biotic stress during the waning stages of the Mesozoic if there had not been an impact. The absence of mass extinction following catastrophic geologic events in a biotic robust world, such as the Middle Ordovician Millbrig-Big Bentonite volcanic event suggests that the biosphere is remarkably resilient to major geologic catastrophes with mass extinction events occurring only when there is a conjunction of geologic events none of which might be capable of producing a global mass extinction by itself.

A large number of conifer pollen cones associated with primitive walchian conifers, including Emporia, occur within an exceptionally preserved fossilized biota near Hamilton, Kansas, USA. The fossils are derived from channel deposits within the Upper Pennsylvanian (Stephanian B/C) Topeka Limestone and show excellent external morphology, internal anatomy, and cuticular features. Pollen cones are cylindrical, up to 5 cm long and 1 cm wide and are simply organized. Each pollen cone consists of a nonwoody central axis from which sporophylls diverge in a helical arrangement. Vascular tissue comprises a ring of tiny cauline bundles that divide at intervals to produce a single trace to each sporophyll. Sporophylls consist of a terete stalk and a heeled distal lamina. Sporangia are attached as a cluster on the adaxial surface of the sporophyll stalk. Stomata occur in one or two bands on the inner surface of sporophyll laminae and consist of guard cells surrounded by a ring of subsidiary cells, each with one overarching papilla. The Hamilton specimens provide conclusive evidence that pollen cones with a distinctive morphology were produced by some of the most ancient walchians from both North America and Europe. Contrary to traditional interpretations, these cones differ significantly from those of the Pinaceae. The broad geographic and stratigraphic distribution of this morphology reveals that conifer pollen cones similar to those at Hamilton are more widespread than previously suspected, and provides evidence for the potentially ancestral morphology of all conifer pollen cones.