Conodonts from the upper Burgen, Tyner, and Fite Formations (Middle Ordovician) of eastern Oklahoma include two new species, Phragmodus harrisi and Plectodina tynerensis. The conodont fauna indicates that the upper Burgen through middle Tyner is Whiterockian (pre- to earliest Chazyan) and that the upper Tyner–Fite is probably Kirkfieldian in age.

The Whiterockian Burgen–Tyner preserves a regressive succession of shoreface, lagoonal, and intertidal deposits. That change is reflected by the conodont succession, which shows replacement of a fauna dominated by species of Neomultioistodus, Scandodus?, and Paraprioniodus by one dominated by species of Phragmodus, Plectodina, and Erismodus.

Carbonate deposits of the Kirkfieldian(?) upper Tyner and Fite Formations follow a major hiatus and reflect shallow, subtidal to intertidal conditions. The conodont fauna is composed of species of Aphelognathus, Plectodina, Curtognathus, Erismodus, and Oulodus, among others.

Flume studies conducted on models and specimens of the helically twisted columns from Mississippian platycrinitid crinoids revealed two unique hydrodynamic interactions. Water is deflected up the column from levels near the sediment-water interface where food particles are more abundant. Turbulence, both in the lee and on the upstream side of the column, removes nutrient-poor water and replaces it with nutrient-rich water from near the sediment-water interface. Subsequently, the nutrient-rich water would have been filtered through the feeding apparatus of the crinoid. An upward deflection of as little as 10 percent bottom water would have resulted in a substantial increase in food particle load. Thus, the form of platycrinitid columns gave the crinoid a feeding advantage over otherwise similar crinoids of the same time period. The most diverse and abundant group of Mesozoic–Cenozoic stalked crinoids shows similar column modifications which suggests that the morphology may impart some competitive advantage to the organism.

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.

In his monograph on the fauna of the Utica and Lorraine Formations of New York, Ruedemann (1925b) described a new and unusually young species of Corynoides, C. ultimus. He obtained these specimens from a thin band within the Utica Shale at a locality on Ohisa Creek (a tributary of the more well known Nowadoga Creek) in the Mohawk Valley. Like many of the graptolites from the Utica, the Corynoides ultimus specimens are vague carbon films, extensively exfoliated and difficult to study. Perhaps consequently, Ruedemann's illustrations and measurements are not entirely accurate and do not reveal sufficient detail for meaningful comparison of this taxon with other, better known species.

Illusioluidia teneryi is a new genus and species of asteroid echinoderm described from the Missourian (Upper Pennsylvanian) Wolf Mountain Shale of Texas. Illusioluidia is important because it is strongly homeomorphic with modern Luidia; Luidia has been considered primitive among living asteroids by some authors. Illusioluidia, however, is not ancestral to Luidia or any other modern genus; similarities are convergent. Luidia is a predator, largely on active invertebrates (other echinoderms, mollusks), whereas Illusioluidia is inferred to have been a small-particle feeder. Homeomorphy reflects neither descent nor feeding habits; environmental controls are suggested.

A specimen of the unstalked Cretaceous crinoid Uintacrinus socialis Grinnell, 1876, has a theca with an anomalous appearance that may be attributed to either inaccurate regeneration or unusual taphonomy. The former would entail regeneration of brachials from pinnulars, and inaccurate regeneration of the arms themselves. The latter would imply that the theca was broken into at least three pieces, and then the pieces were rotated with respect to each other. The presence of broken plates and sediment in the line of breakage indicates that the specimen was broken after death, and the taphonomic explanation is favored. Of the hundreds of known specimens of this species, this is the only one with such an appearance.

The first occurrence of a pterosaur fossil from the Early Cretaceous of Peru is reported. The specimen consists of a nearly complete right humerus of a pteranodontid pterosaur preserved in three dimensions, presumably in a concretion. The Pteranodontidae is rediagnosed, and included genera and materials are listed. The Nyctosauridae and Dsungaripteridae are also diagnosed on the basis of postcranial characters, and the relationships of those three taxa plus the Azhdarchidae are discussed. The species Santanadactylus spixi Wellnhofer (1985) is reassigned to the Dsungaripteridae.

The ichnogenus Didymaulichnus has previously been reported in rocks of upper Precambrian-Carboniferous age (Häntzschel, 1975; Pickerill et al., 1984). Didymaulichnus has been postulated by different authors to be an epistratal grazing trace of trace makers ranging from molluscs and other soft-bodied animals to arthropods (Young, 1972; Häntzschel, 1975; Bradshaw, 1981; Hakes, 1985). If this is the case, it is reasonable to assume Didymaulichnus occurs in sediments and sedimentary rocks that are as young as the modern. In an examination of the Cardium Formation (Upper Cretaceous, Turonian) this ichnogenus occurred with relative abundance.

Amia? chauliodeia, a new amiid fish from the Late Cretaceous Fruitland Formation of the San Juan Basin, New Mexico, is described from material that includes vertebral centra, elements of the mandibular arch, dermal skull roof, palatal complex, hyoid arch, pectoral girdle, branchial apparatus, ribs, and both pelvic basipterygia. The new form differs from previously described amiiforms in the length of the dentary tooth row, in the anterior thickness of the dentary, and in the apparent lack of internal sensory canals in the dentary and angular. The New Mexico amiid also retains a primitive metapterygoid. Although the new form shares several features in common with the Late Cretaceous amiid Melvius thomasi described by Bryant (1987), it is unquestionably distinct from this form. Material from the Fruitland and Kirtland Formations of New Mexico referred by Bryant (1987) to M. thomasi is now included within Amia? chauliodeia.

Reports of Mississippian polyplacophorans from North America are rare. To date only three species, Gryphochiton parvus (Stevens, 1858) and G. elevatus (Kues, 1978), from the Salem Limestone in Indiana, and Elachychiton juxtaterminus Hoare and Mapes, 1985, from the Imo Formation in Arkansas, have been recognized (Smith and Hoare, 1987). Lobarochiton anomalus (Rowley, 1908), from the Louisiana Limestone in Missouri, is now believed to be Devonian in age. European reports of Lower Carboniferous polyplacophorans are much more common, at least 29 species (Hoare and Smith, 1987). The location of any specimen in the Mississippian of North America becomes significant in filling out the geologic history of this taxonomic group.

The tarsus and distal end of the tibia are described in Herrerasauridae, a family that includes the oldest known dinosaurs. This tarsal configuration is compared to those of more advanced dinosaurs and to other archosaurs. Through phylogenetic analysis of the morphological characters, a picture emerges of the evolutionary changes in the ankles of early dinosaurs.

The tibia of the herrerasaurids has a quadrangular distal articular surface, with a shallow ventrolateral notch. This morphology is strikingly similar to that of the lagosuchid thecodonts Pseudolagosuchus and Lagosuchus and represents the most primitive tibial condition known for Dinosauria.

Aside from the derived states possessed by Theropoda, Sauropodomorpha, and Ornithischia, respectively, it was impossible to recognize synapomorphies in tibiotarsal anatomy shared by these groups exclusive of Herrerasauridae. The transverse broadening of the distal end of the tibia seems to have been attained independently by ornithischians, theropods, and sauropodomorphs.

The tarsus of herrerasaurids is characterized by an astragalus with a small but conspicuous lateroventral depression, by a pyramidal calcaneum with a ventromedial projection that articulates into the cavity of the astragalus just mentioned, and by a posterolaterally directed calcaneal tuber. These characters are also seen in Lagosuchus (a close relative of dinosaurs), in the prosauropod Riojasaurus and, insofar as the astragalus is concerned, in the primitive dinosaur Walkeria, which suggests that dinosaurs of different lineages shared the same tarsal condition.

By definition, this type of articulation between the astragalus and calcaneum follows the “crocodile-reversed” tarsal condition, suggesting that the tarsus in lagosuchids and dinosaurs could be derived from the “crocodile-reversed” pattern present in Ornithosuchidae and Euparkeria. In contrast, the mesotarsal ankle of lagosuchids and dinosaurs lacks the synapomorphies of the “crocodile-normal” ankle present in Crocodylia, Rauisuchidae, Aetosauria, and other archosaurs.

It is concluded that Herrerasauridae retained the primitive tibiotarsal condition for Dinosauria, from which those of the Ornithischia, Sauropodomorpha, and Theropoda were derived. Furthermore, tibiotarsal anatomy supports monophyly of Dinosauria.

The Somerset Shale Member (Mississippian: Valmeyeran) is a discontinuous shale at the base of the Salem Limestone in southern Indiana and central Kentucky. It is the only significant terrigenous unit within a thick sequence of shoaling carbonates deposited on the eastern side of the Illinois Basin over the Borden Delta siltstones. The Somerset Shale contains a diverse echinoderm fauna of blastoids (five species), crinoids (20 species), and echinoids (two species). Most of the species are known only from the Somerset or from carbonate rocks directly above and below the Somerset Shale. There remains a small number of species previously known mostly from terrigenous rocks (the Borden Delta) below the carbonates. This demonstrates that at least some of the faunal differences between the Borden crinoids and those of the overlying carbonates are the result of paleoecologic factors. The Somerset Shale may mark a useful biostratigraphic boundary defined by last occurrences of the genera Barycrinus, Cyathocrinites, and Actinocrinites and the base of the range of Batocrinus. The species Batocrinus somersetensis n. sp., Dizygocrinus calvus n. sp., and Barycrinus punctus n. sp. are described.

Trace fossils figured in four recent papers in the Journal of Paleontology and Palaios have been reposited in the Invertebrate Paleontology Collection of the Cleveland Museum of Natural History (CMNH). Catalog numbers for these specimens are herein assigned.

A recent review (Haman, 1988) of the publication “Foraminiferal Genera and Their Classification” by Alfred R. Loeblich, Jr. and Helen Tappan, Van Nostrand Reinhold Company, New York, incorrectly indicated the date of its publication as “early 1988,” although adding, parenthetically, “The senior author refers to the publication date as December, 1987, A. R. Loeblich, Jr., January, 1988, written communication.”