Disarticulated spines and sclerites of assumed multiple row problematic organisms are present in several Mississippian and Pennsylvanian stratigraphic units. Marginal spines and dorsal spinose sclerites are present. Marginal sclerites are distinguishable into anterior, posterior, and left- and right-handed lateral forms. The new family Aenigmatectidae and genus Aenigmatectus with two new species, A. hystricosus and A. magnacavus, are recognized. Aenigmatectus sp. from the Mississippian is also described. The family is tentatively assigned to the order Hercolepadida Dzik, 1986.

Several specimens of the large, discoidal, new inozoid genus and species, Gigantospongia discoforma, have been discovered in the Upper Permian, Upper Capitan Limestone in the northern Guadalupe Mountains of New Mexico, near Carlsbad Caverns. The holotype is nearly 2.5 meters across, as exposed, and ranges from 8-20 mm thick, with numerous canals transverse and parallel to the principal plane. These canals are approximately 1 mm in diameter and separated by tracts 1-2 mm thick. Thickened dermal and gastral layers, each approximately 1 mm thick, occur at tops and bases of both the holotype and associated paratypes in the “Sponge Window” exposures of Bat Cave Draw, and in specimens from Chinaberry and Hackberry Draws. Inverted Lemonea conica Senowbari-Daryan, 1990, is apparently attached to the base, and appears to have grown inverted in a void formed or capped by the tabular inozoid. Well-preserved specimens of Amblysiphonella also appear inverted, as do examples of Lemonea cylindrica (Girty, 1908), a new species of Lemonea, and Guadalupia explanata (King, 1943), which occur between the holotype and an underlying paratype. All appear coated with Archaeolithoporella crusts. Microstructure of the inozoan skeleton is obscured by diagenesis.

Brachiopods assigned to eight genera and 15 species have been recovered from Upper Cambrian (Franconian and Trempealeauan Stages) and lowest Ordovician strata in the Arbuckle and Wichita Mountains of Oklahoma. Species of Ocnerorthis and Eoorthis occur in the Reagan Sandstone and Honey Creek Limestone of the Timbered Hills Group. Species of Billingsella appear in the Honey Creek and range upward into the overlying Fort Sill and Signal Mountain Limestones of the Arbuckle Group. Species of Cymbithyris, Finkelnburgia, Nanorthis, and Apheoorthis succeed each other upsection in the Signal Mountain Limestone. Five brachiopod zones and one subzone have been established that can be used to correlate the measured sections in the Arbuckle and Wichita Mountains, and to correlate with varying degrees of confidence from Oklahoma to similar brachiopod occurrences in other areas in the United States.

Observed diversity of bryozoans within Devonian stages is not significantly different from range-through values for species because very few species have ranges longer than a single stage. Generic diversity differs significantly between observed stadial and stadial range-through values except for the diverse Givetian faunas. Among families, observed stadial and range-through comparisons differ significantly in the lower diversity Early and Late Devonian but are not significant in the taxonomically diverse Middle Devonian. The patterns of Devonian generic and familial diversity are apparently robust proxies for specific diversity.

Givetian specific and generic extinctions, based on generated bootstrap distributions, are significantly higher than the other six Devonian stages even when modifications for different stage durations are considered. Based on present data, we conclude that a major change in Devonian diversity occurred between the Givetian and the Frasnian stages. Givetian specific and generic extinctions are not “smeared” with respect to adjacent stages and should qualify as a mass extinction among bryozoans pending more accurate data on bryozoan ranges and more precision in radiometric dating of Devonian stadial boundaries. Devonian bryozoan familial extinctions are not numerous and do not exhibit a significant number of extinctions for any stage. The Givetian extinction, which for the time being ranks as the largest bryozoan extinction in the Phanerozoic, is a global event with a marked local effect in the Hamilton-Tully fauna of New York, Pennsylvania, and Ontario.

Givetian specific originations are significantly higher than bootstrap distributions for both raw data and data modified for stadial durations. A Givetian generic high in originations for raw data is not significant when modified for stadial durations and only Eifelian familial originations are significantly higher than bootstrapped distributions.

North American Pacific Slope deposits of Coniacian to Maastrichtian age have yielded eight biostratigraphically useful species of Anchura: A. (Helicaulax?) popenoei new species, Coniacian; A. halberdopsis new species, early Campanian; A. callosa Whiteaves, 1903, early Campanian; A. falciformis (Gabb, 1864), late early to middle Campanian; A. phaba new species, middle to late Campanian; A. ainikta new species, middle to late Campanian; A. gibbera Webster, 1983, late Campanian to early Maastrichtian; A. baptos new species, late Maastrichtian to early Danian. In addition, two other possible species are A. nanaimoensis (Whiteaves, 1879), middle to late Campanian, and Anchura? new species, late Maastrichtian. These species together with two additional Turonian species, A. (Helicaulax) tricosa Saul and Popenoe, 1993, and A. (H.) condoniana Anderson, 1902, allow the definition at least eight Late Cretaceous Anchura zones for the Pacific Slope. These zones have durations of 1.5 m.y. to 4 m.y.

Anchura (H.?) popenoei from northern California appears most closely related to A. (Helicaulax) tricosa Saul and Popenoe, 1993, of Turonian age from southern California. Anchura callosa, A. falciformis, A. nanaimoensis, and A. phaba appear to be closely related based on sculptural elements, as does A. gibbera despite having an anterior spur on the wing. However, these species appear to belong to two latitudinally differentiated faunal provinces. Species having a northern range include A. callosa, A. falciformis, and A. nanaimoensis, whereas A. phaba and A. gibbera are from more southern deposits, as are also A. halberdopsis, A. ainikta, and A. baptos.

The emended descriptions of the genus Amphitriscoelus and the species A. waringi Harris and Hodson are given, and a new species is proposed (A. pluriloculata). These rudist bivalves are derived from a thick Lower Cretaceous sequence of carbonate sediments interlayered with siliciclastic, volcaniclastic, and volcanic rocks in southwestern Mexico, near Huetamo, in the State of Michoacan. The species belong to a recently discovered rich fauna containing other rudists, nerineid gastropods, orbitolinid foraminifers, and calcareous algae. The fauna shows a close affinity with the Amphitriscoelus fauna of northern South America. Similar assemblages are also present in Texas, Cuba and other Mexican localities. The wide distribution of the fauna allows interpretation of paleogeographic relations among all the regions as well as interpretation of paleoecological similarities. The existence of an homogeneous large faunistic province during the Early Cretaceous is suggested.

The Lower Ordovician (Ibexian) Fort Cassin Formation of New York State and Vermont consists mainly of carbonates that were deposited in a subtidal storm-influenced setting. The low diversity trilobite fauna is dominated overwhelmingly by the isoteline, Isoteloides. Eleven species representing at least nine genera are described; Acidiphorus whittingtoni is new. The bathyurine genus Goniotelina Whittington and Ross is regarded as paraphyletic and is synonymized with Acidiphorus Raymond. The presence of Isoteloides canalis (Whitfield; = I. latimarginatus Fortey), I. peri Fortey and Bathyurellus platypus Fortey indicates a correlation of the Fort Cassin with the Strigigenalis caudata Zone of the Catoche Formation of western Newfoundland.

A distinctive new genus (Xyoeax) and two new species (Xyoeax eponcus, Scutellum sudorum) of styginid trilobites are described from the late Early Devonian (Emsian) Murrindal Limestone of eastern Victoria, Australia. Limited material of a third styginid species not belonging to any named genus is also described from the same locality. Xyoeax is considered to be closely related to Ancyropyge Clarke, 1891, and Weberopeltis Maksimova in Moore, 1959, and less closely related to Kolihapeltis Prantl and Přibyl, 1947. Weberopeltis is revised and newly diagnosed. Several species previously assigned to Weberopeltis are transferred to the new genus Exastipyx, which is considered to be related to Cornuscutellum Snajdr, 1960. Ancyropyge, Exastipyx, Weberopeltis, and Xyoeax all have pygidia with long pleural spines derived by reduction of the pleural field between the pleural ribs, whereas Kolihapeltis and Cornuscutellum lack pygidial spines. Pygidial morphology of Xyoeax type has thus arisen independently in separate styginid lineages. The type species of Altaepeltis Maksimova, 1968 is established as Weberopeltis bublitchenkoi Maksimova, 1960, by monotypy.

Glabellar lobes of holaspid cranidia of trilobites have been numerically designated, LI, L2, etc. (Jaanusson, 1956; Henningsmoen, 1957, figure 1), or lp, 2p, etc. (Harrington, 1959), forward from the occipital ring; most trilobites have four glabellar lobes and an occipital ring. The description of morphological structures with an identical term implies that the structures are homologous in different organisms of a certain group (Inglis, 1966); this is one of the classical definitions of homology (Patterson, 1982). This also seems to be an initial conjecture of homology (“primary homology” of de Pinna, 1991). Likewise, the numerical notation of glabellar lobes should allow us to recognize homology of the lobes among trilobite taxa. Under the above traditional system, the homology is demonstrably recognized in ontogenetic stages with a distinctively differentiated protopygidium (stage 2 in Figure 1); however, this is not the case for earlier intervals occurring before transverse demarcation at the back of the head (stage 1 in Figure 1). This limitation is because the relationships of the occipital ring of the later stages to the posterior axial lobes of the earlier ones are uncertain, and this can be appreciated, when describing a phacopoid protaspis with four axial lobes (stage 1 of Rossaspis pliomeris in Figure 1). We introduce a new term, “Lp”, for the posteriormost axial lobe to remove this limitation, while keeping the traditional system useful. The previous system using letters “L” (after lobus) and “S” (after sulcus), proposed by Jaanusson (1956, p. 37), is preferred over the system using “p”, because “p” of the latter confusingly refers to lobes or furrows (e.g., Harrington and Leanza, 1957, p. 221)

Epibionts on specimens of Flexicalymene (Late Ordovician, Cincinnati Arch region, U.S.A.) that were encrusted while alive show an apparent preference for attachment along the relatively elevated sagittal axis of the exoskeleton (glabella, axial rings of thorax and pygidium) or the medial portion of the cephalic doublure. This site-specificity supports an interpretation of a semi-infaunal habit for this trilobite and may indicate a commensal relationship between the epizoan and host (e.g., epizoan bryozoans exploiting the trilobite exoskeleton as a hard substrate and perhaps benefitting from feeding currents generated by the trilobite). Epizoans are found only on larger individuals of this trilobite, suggesting a terminal molt stage for Flexicalymene.

Although the number of previously reported encrusted trilobites is small, a survey of the literature suggests the following hypotheses concerning the relationships between trilobite life habit and susceptibility to epizoan colonization: 1) infaunal (burrow dwelling) trilobites were generally free of epizoans; 2) a small proportion of shallow-burrowing (semi-infaunal or “ploughing”) trilobites were suitable hosts for epizoans, but the epizoans preferentially colonized the elevated or anterior portions of the exoskeleton; 3) epifaunal (and some pelagic?) trilobites were more susceptible to encrustation.

The genus Baffinicythere is a northern high-latitude marine ostracode, which includes four species: B. howei Hazel, B. ishizakii new species, B. reticulata new species, B. robusticostata new species. The first species occurs only in late Pliocene to Recent sediments of the Arctic and northern Atlantic Oceans. The remaining three species are abundant in the Plio–Pleistocene formations of northern Japan, which yield cold-water molluscan faunas. Detailed morphological analyses and paleogeographic distribution of the three new species indicates that: 1) B. reticulata has some primitive characters relative to the other two species; 2) B. ishizakii and B. robusticostata seem to have had different strategies as regards rate of ontogenetic size increase; 3) the left valve outlines can be resolved into two components, ontogenetic shape changes and species-specific distinctions among the species; and 4) B. robusticostata invaded areas inhabited by B. reticulata and may have excluded it during the late Pleistocene. The Atlantic species B. howei has not been recorded from northern Japan. Comparisons of B. reticulata and B. howei, based on their pore distribution and reticulate sculptures, suggest that B. reticulata could have migrated to the Arctic Province after the Bering land barrier had been breached and then evolved rapidly into B. howei.

A new species of Graptocarcinus is the stratigraphically youngest known member of the genus; it is here described together with a new species of the genus Caloxanthus from the late Maastrichtian of The Netherlands. The known stratigraphic distribution and paleobiogeography of both genera are discussed. The range of Graptocarcinus is extended from the Aptian to the late Maastrichtian.

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 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.

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.

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.

Kellogg (1936, p. 242) described “an imperfectly preserved dorsal vertebra” from Texas, which he assigned to the primitive cetacean genus Protocetus. McLeod and Barnes (1990), however, were the first to report unequivocal protocetid remains from the Atlantic Coastal Plain. Since then, Hulbert and Petkewich (1991) and Hulbert (1993) have noted a well-preserved skeleton of a protocetid cetacean from middle Eocene deposits in Georgia. The purpose of this note is to report the recent discovery of additional protocetid remains from the coastal plain of South Carolina and to discuss their stratigraphic and biostratigraphic context.

In a recent paper D'Alessandro and Iannone (1993) introduced the new ichnogenus Caudichnus, with one ichnospecies Caudichnus annulatus, for drum-shaped trace fossils. The trace fossil comprises several structural elements and, in order to provide a uniform terminology, these elements are denned in Figure 1.

The first occurrence of Discoaster diastypus Bramlette and Sullivan is a marker for the CP8/CP9 zonal boundary in the widely used nannofossil zonation of Okada and Bukry (1980). This zonal boundary has commonly been used to approximate the Paleocene/Eocene boundary (e.g., Berggren et al., 1985; Perch-Nielsen, 1985). In spite of the frequent use and importance of D. diastypus in biostratigraphy, there has been some confusion about this species in the literature, including some of the most used references. For instance, Bramlette and Sullivan (1961), who first described the species, incorrectly defined D. diastypus in terms of its ray number and size (see Figure 1), and included a specimen of Discoaster falcatus Bramlette and Sullivan as an isotype of D. diastypus (Bramlette and Sullivan, 1961, pi. 11, fig. 6). Perch-Nielsen (1971, pi. 51, figs. 8 and 10) figured a specimen of Discoaster barbadiensis Tan and another specimen of Discoaster bifax Bukry as D. diastypus. These mistakes apparently have gone unnoticed and were adopted by Romein (1979, p. 168) and incorporated in the Handbook of Cenozoic Calcareous Nannoplankton (Aubry, 1984, p. 46, fig. 111; p. 48, figs. 114 and 115).

As part of the preparation for reviewing the Paleozoic rhynchonellids for the revised brachiopod treatise, one of us (NMS) requested help from Dr. Howard Brunton, of the Natural History Museum (British Museum, London) in obtaining type material of Propriopugnus pugnus (Martin) to further investigate the internal features. Dr. Brunton kindly sent a Natural History Museum specimen that he considers to be close to the lectotype. This specimen has been photographed and sectioned, and it is described below.