Ptyctodonts from the Upper Devonian Martin Formation on Mt. Elden, northern Arizona, were hitherto known only from tooth plates ascribed to Ptyctodus bradyi. Recent collections include dental elements of P. bradyi as well as body and skull plates and dental elements of a previously unknown ptyctodont, described here as Denisonodus plutonensis new genus and species. Comparison with other ptyctodonts suggests that the new genus has close affinities to other North American forms. As the holotype of Ptyctodus bradyi has been lost a neotype is designated here.

Examination of 186 specimens of the living brachiopod Laqueus rubellus (Sowerby), collected during four different months from Sagami Bay, Japan, has yielded 94 specimens of the pinnotherid crab, Pinnotheres laquei Sakai, living within the mantle cavity. This work provides the first quantitative statements regarding crab/brachiopod associations. All but four of the specimens were female crabs; the four male specimens occurred together with females in brachiopods collected during March, 1982. Pinnotherids, common associates of mollusks and echinoderms, tend to be host specific; however, anecdotal information received near the conclusion of this study suggests that P. laquei may visit multiple brachiopod host species. Although the crabs seem to be more common in larger brachiopods, there is some correspondence between crab size and brachiopod size. No physical evidence, such as malformation of the shell or lophophore loop, was observed in host brachiopods and, therefore, the association was judged to be commensal or symbiotic. It is probable that crabs were able to enter and exit the mantle cavity at will. This association of brachiopod and pinnotherid represents the only known occurrence of infestation of brachiopods by crabs and, with the exception of boring and encrusting organisms, is one of very few biotic associations, of any kind, for brachiopods. Although this association has not yet been reported from the fossil record, the nature of preservation of brachiopods and the methods of study, employing serial sectioning techniques, suggest the possibility of detecting this unusual association in the fossil record.

It is well known that echinoderm skeletal elements behave optically as single calcite crystals, but one implication of this observation, that skeletal units have crystallographic axes with characterizable orientations, has received little attention. This paper examines patterns of crystallographic axis orientations in 43 blastoid species and assesses their usefulness to the study of homology among echinoderm skeletal elements, phylogeny both within blastoids and at higher taxonomic levels, and biomineralization processes.

Calcite decoration and optical goniometry techniques reveal intraspecific and interspecific patterns of variation in the orientations of c and a crystallographic axes in the three major sets of blastoid thecal plates. Within species, basal, radial, and deltoid c axes all show consistent orientations, clustering near the meridional plane that bisects each plate. In contrast, a axes of most plates have random orientations, although for a few plates a axes are clustered rather than random. While c axes from different species all fall about the meridional plane bisecting each plate, inclinations within this plane vary, so crystallographic data can provide new characters for phylogenetic analysis.

In assessing homologies among deltoid plates, axes of posterior deltoids show little correspondence with those of regular deltoids, possibly suggesting a nonhomologous origin. Superdeltoids and epideltoids have commingled c axis orientations and may be homologues.

Consistent c axes within species suggest molecular or cellular control of biomineralization during development, but the occurrence of both random and constrained a axes, depending on the plate examined, implies heterogeneities in this control affecting different plates on the theca.

The Survey Peak Formation (350 m thick) consists of calcareous shale, mudstone, siltstone, and limestone-pebble conglomerate, and is formally divided into four revised members, successively: Basal Silty Member, Putty Shale Member, Middle Carbonate Member, and Upper Carbonate Member. The Wilcox Pass section, Jasper National Park, Alberta, provides a standard stratigraphic section for the southern Canadian Rocky Mountains and yielded over 4,500 conodonts from 87 samples which are of high species diversity, moderately well preserved, with a conodont Color Alteration Index (CAI) value of 3. Over 50 multielement species representing some 20 genera are identified, and most are illustrated. Conodont zones recognized in the four members include: Basal Silty Member—Eoconodontus notchpeakensis, Cordylodus proavus, C. caboti, C. intermedins, and C. lindstromi; Putty Shale Member—lower C. angulatus; Middle Carbonate Member—upper C. angulatus and coeval Rossodus manitouensis, Colaptoconus priscus (new) and Scolopodus cf. S. rex; Upper Carbonate Member—Striatodontus lanceolatus-S. striatus. In total, ten conodont lineage and assemblage zones are recognized within the Survey Peak Formation. Most can now be precisely correlated with trilobite faunas and acritarch microfloras described from this section, and with conodont zones established for the Great Basin area, Utah-Nevada, and for western Newfoundland. The Survey Peak Formation is of uppermost Cambrian to lower Ibexian (Tremadoc) in age with the Cambrian-Ordovician boundary placed between 26 and 29 m above the base of the formation in the Basal Silty Member.

Small bioherms in the uppermost Tansill Formation and Capitan Limestone in the northern Guadalupe Mountains, New Mexico, have been informally interpreted as sponge reefs by past workers. Samples collected during the present cycle of field work in 1993 and 1994 suggest that some of these isolated carbonate mounds have a different origin. Guadalupe Mountains complexes have been recognized for many years as outstanding models for interpretation of reefs, reef facies, and reef faunas (for example, King, 1948; Newell et al., 1953; Achauer, 1969; Yurewicz, 1976, 1977; Babcock, 1977; Kirkland et al. 1993).

Two species and genera of pteraspidids (Agnatha, Heterostraci), Blieckaspis priscillae n. gen., and Panamintaspis snowi n. gen. and n. sp., together with two undetermined species, are described from the lower part of the Lippincott Member of the Lost Burro Formation, southeastern California. The sharing of similar faunal elements with the Early Devonian assemblages of the Sevy Dolomite and Water Canyon Formation of Utah and Nevada, respectively, together with stratigraphic constraints on the age of the Death Valley fauna, suggest that these assemblages are age equivalent and have a late Emsian (inversus–serotinus Zones) age. The vertebrate-bearing unit of the Lippincott Member is interpreted as a channel-fill deposit laid down in an estuarine environment with low or fluctuating salinity.

The silurian graptoloid genus Globosograptus was erected by Boucek and Přibyl (in Přibyl 1948, p. 37), who selected as type species Monograptus wimani Bouček, 1932. As noted by Bulman and Rickards in the Treatise (Bulman 1970, p. V155), Globosograptus “was based on the silhouette appearance of a slender Llandovery species on which the thecae possess a long prothecal portion, no thecal overlap, and a seemingly enrolled methathecal portion. The nature of this enrollment is indefinite … The genus has no precise significance and its application is quite impracticable.”

A partial nodosaurid ankylosaur skeleton, consisting primarily of the ilia, hindlimbs, posterior dorsal armor, plus partial forelimb elements and additional armor, was recovered from the marine Point Loma Formation, late Campanian age, north of San Diego, California. The specimen is similar to contemporaneous species of Panoplosaurus and Edmontonia from terrestrial sediments of the western interior, but there are also similarities to the armor of Stegopelta landerensis from marine sediments of earliest Cenomanian age from Wyoming. Skeletal elements critical for generic determination are not preserved, and the specimen is identified as Nodosauridae, incertae sedis. An associated marine invertebrate fauna and nannoplankton flora have revealed some discrepencies in the correlation systems used for Upper Cretaceous marine rocks of coastal California. Hollow limb bones of the specimen are interpreted as a preservational artifact. Nodosaurids had broad ecological tolerances, and visited riparian and coastal environments more frequently than other dinosaurs. However, a review of morphologic and distributional evidence fails to support a theory of amphibious or aquatic habits for nodosaurids.

As part of a study of vertebrate trackways in the cross-stratified Coconino Sandstone (Permian) of northern Arizona, trackways made by living salamanders under different substrate conditions were compared. The sample of 230 trackways of the western newt, Taricha torosa, included ten combinations of the following substrate characteristics: 1) sediment: muddy or of fine sand; 2) attitude: level or sloped (25 degrees); 3) moisture content: dry, damp, wet, or submerged.

Trackways in wet mud produced the most accurate representation of the number of toes per foot and the arrangement of toes. All other conditions studied yielded a reduced average number of toes per foot, and a large sample was needed before the data had the potential to indicate the true structure of the trackmaker's feet. Trackways made on sloped, submerged mud or sand, sloped, dry sand, and sloped, damp sand rarely included the full complement of toes. The positions and orientations of the toe marks were distorted if the animals were walking underwater or on sloped, damp sand. Trackways on the slopes of cross-stratified deposits make reliable identification of the trackmaking animals exceptionally difficult.

The Manchioneal Formation of Jamaica has yielded a diverse fauna of Pleistocene echinoids. Taxa include Stylocidaris affinis (Philippi), Cidaris (Tretocidaris) bartletti (A. Agassiz), Eucidaris tribuloides (Lamarck), diadematid indet. gen. et sp., arbaciid indet. gen. et sp., Echinoneus cyclostomus Leske, Echinolampas depressa Gray, Clypeaster indet. sp. or spp., Paleopneustes cristatus A. Agassiz, various indeterminate spatangoids and regular indet. gen. et spp. Taxonomically diverse echinoid faunas have now been documented from a range of facies in the Jamaican Pleistocene. Eucidaris tribuloides is ubiquitous, but most taxa are limited to particular facies. Clypeasteroids are only locally common, despite the high preservation potential of their tests. Echinoid and crinoid taxa in the Manchioneal Formation suggest deposition in ≥ 100 m water depth, and probably shoaling upwards.

A tooth battery, palatoquadrate, and a gill-arch element of Bobbodus schaefferi were collected from Late Pennsylvanian/Early Permian (Asselian) rocks near Manhattan, Kansas. Depending on the placement of the Pennsylvanian–Permian boundary, this specimen extends the upper limit of the species from the Virgilian (Gzelian) into the Gearyan (Asselian). The new range thus is Kasimovian to Asselian, a 15 my interval. Based on features of the palatoquadrate, the diagnoses of the order Eugeneodontida and the superfamily Caseodontoidea are revised. Bobbodus is the most primitive genus of the order Eugeneodontida.

The large number of ichnospecies in Permian vertebrate ichnology literature is often a result of a failure to recognize substrate or gait-controlled variations in trackway morphology. Additionally, regional studies were often performed in isolation from studies in other areas. Nomenclatural priority applies to the names first assigned to trackways from the Corncockle and Locharbriggs Sandstone Formations (Permian) of Dumfries and Galloway, Scotland. Only one ichnogenus, Chelichnus, and four ichnospecies are recognized here and all had been identified in the studies of Jardine in 1850 and 1853. Chelichnus represents tetrapod trackways with rounded manus and pes impressions, subequal in size with up to 5 short digits where preservation is complete. The normal trackway pattern shows a pes pace angulation of up to 90° with the manus and pes being impressed close together or possibly with a slight overlap of the manus by the pes. Chelichnus bucklandi shows a pes size of 10 to 25 mm, C. duncani shows a pes size of 25 to 75 mm, C. gigas shows a pes size of 75 to 125 mm, and C. titan displays a pes size exceeding 125 mm in length. This restriction to four ichnospecies is more in accord with the low faunal diversity to be expected from an eolian environment of Late Permian age than was the former taxonomic classification. The Permian ichnofaunas of the Coconino Sandstone of Arizona and the Cornberger Sandstein of Germany are also composed largely of these four ichnospecies.

Fragmentary remains of a long-frilled ceratopsian dinosaur from the El Picacho Formation (Maastrichtian) of West Texas pertain to an undescribed form. The remains are, however, insufficient to fully characterize this species. This ceratopsian has long thick squamosals with marginal undulations, nasals lacking a discrete horncore, a thin parietal, and large trihedral epijugals. The braincase has very thick lateral walls, and a well-developed postfrontal foramen. Four species of horned dinosaurs are known from Upper Cretaceous strata of the American Southwest: Pentaceratops sternbergii, Chasmosaurus mariscalensis, Torosaurus utahensis, and the El Picacho ceratopsian. All of these belong to the subfamily Chasmosaurinae.

Many ichnological taxa named by Edward Hitchcock have never been adequately described and illustrated. Among these is the ichnogenus Antipus Hitchcock (1858, p. 115) with two species: A. flexiloquus based on specimens AC (=Amherst College, Amherst, Massachusetts) 35/25 and AC 41/52 (designated the type specimen by Lull 1904, p. 536); and A. bifidus based on specimens AC 23/3, AC 17/2, and AC 23/2 (designated the type specimen by Hitchcock 1865, p. 56). Lull (1904, p. 536) regarded A. bifidus as “… extremely doubtful…” and did not consider it in later publications (e.g., Lull 1915, 1953). The impressions ascribed to A. bifidus might be organic in origin, but if they are trackways, they are totally unlike the tracks of A. flexiloquus. Antipus bifidus is here regarded a nomen dubium because it is undiagnostic. Referred specimen AC 35/25, a small, thin slab of micaceous shale (approximately 87 mm by 96 mm, less than 2 mm thick) that is not mentioned by Lull (1904, 1915, 1953), has one manus and possibly one pes track of such poor quality that analytic comparison to the type of A. flexiloquus is impossible. Therefore, the ichnogenus Antipus has a single species, A. flexiloquus, known only from the type specimen, AC 41/52. Two of the eleven tracks on AC 41/52 have been illustrated (Hitchcock 1858, plate 20, fig. 10; republished with minor revision by Lull 1915, fig. 117; these two tracks are here designated M2 and P4). These simple outline sketches do not accurately portray details of the tracks, and the full trackway pattern was not illustrated.

Apparatus-based conodont taxonomy has organized the plethora of generic and specific names of form-based taxonomy into a more biologically and phylogenetically sound taxonomy (Schopf, 1966; Webers, 1966; Bergström and Sweet, 1966; Sweet and Bergström, 1972; Rhodes and Austin, 1981; Sweet, 1981, 1988). In the transition from form-based to apparatus-based taxonomy, some conodonts that are not very common, or that have only one or two element types in their apparatus, have remained in a state of form-based taxonomy limbo. An example of this is Trichonodella? tricurva (Schopf, 1966). This relatively uncommon species was known from only one element type (Schopf, 1966) and has not been used in biostratigraphy. Schopf (1966) questioned the generic assignment of T.? tricurva and noted its distinct morphology. Sweet and Bergström (1972) indicated that the type species of Trichonodella (Branson and Mehl, 1948) is a junior synonym of Plectodina aculeata, or of a closely related Plectodina species. Trichonodella? tricurva does not fit within the apparatus-based generic concept of Plectodina (Sweet, 1981), and it is therefore inappropriate to refer it to Trichonodella or Plectodina. No genus contains a tertiopedate element that is morphologically similar to the holotype of T.? tricurva (Schopf, 1966). Additional material from strata that are in part coeval with the stratum typicum of T.? tricurva supports the idea that T.? tricurva represents a new genus. The new genus Schopfodus is proposed for the conodont elements described by Schopf as T.? tricurva and the associated elements of its apparatus.

Late Tertiary Carnivores are rare as reported in the fossil record for Mexico. The felids discussed in this paper from the state of Guanajuato represent the most diverse assemblage of this taxonomic group thus far known from the country. They include Machairodus cf. M. coloradensis, Pseudaelurus? intrepidus, and Felis cf. F. studeri. The last-named taxon has not previously been recognized from the late Tertiary of Mexico, and Pseudaelurus has only questionably been identified in the country (but not described or discussed). None of these taxa have yet been reported from areas further south. While age determinations for the above felids from Guanajuato were based on associated faunal constituents, especially abundant and diverse equids, the felids themselves can be useful as chronostratigraphic indicators.