Two new specimens of Hyaenodon venturae from the early Chadronian (latest Eocene) of Wyoming provide new information about this rare, miniature hyaenodont, and extend the upper end of the temporal range of the species. The significant difference between H. venturae and H. microdon, the two smallest North American species of Hyaenodon, is the absence of synostosis of the mandibular symphysis in adult H. venturae. In Hyaenodon microdon, from the middle Chadronian, on the contrary, fusion of the symphysis is complete while the individual is still in the juvenile stage of ontogenesis, before the eruption of m3. Within the genus Hyaenodon the ml becomes relatively smaller as the length of the tooth row (pl-m3) increases; this relationship can be demonstrated in the series of species from the miniature H. venturae to the giant H. megaloides.

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.

In 1992 Sander described in this journal a find of the ichthyosaurian genus Cymbospondylus from the Middle Triassic of Spitsbergen. At the time of publication, the specimen illustrated in figures 2-4 (Sander, 1992) and five associated elements (not figured) were housed at the Paleontological Institute and Museum of the University of Zürich (PIMUZ A/III 496 and PIMUZ A/III 647-651). These specimens were later donated by their collector and owner Professor Hans-Joachim Schweitzer (Bonn) to the Paleontological Museum of the University of Oslo (PMO), where they are now stored under the following numbers:

• PMO 162.003 (=PIMUZ A/III 496, figs. 2-4 in Sander, 1992)

• PMO 162.004 (=PIMUZ A/III 647)

• PMO 162.005 (=PIMUZ A/III 648)

• PMO 162.006 (=PIMUZ A/III 649)

• PMO 162.007 (=PIMUZ A/III 650)

• PMO 162.008 (=PIMUZ A/III 651)

Dental and postcranial remains of a donkey-sized, three-toed, primitive horse were collected from the “Undifferentiated Miocene” Ecor Rouge Sand (which underlies the widespread Citronelle Formation) from the Mauvilla site in southern Alabama. These fossils probably pertain to a single individual of Protohippus gidleyi Hulbert, 1988. This represents an exceedingly rare occurrence of a late Tertiary land mammal from the central Gulf Coastal Plain and allows comparisons with better-known, contemporaneous land-mammal assemblages from Florida. Based on the known biochronology of Protohippus gidleyi from other localities, and the stratigraphic position of the Mauvilla record, the age of: 1) the Ecor Rouge Sand is late Miocene (latest Clarendonian to early Hemphillian landmammal “age”), between 9.0 to 6.5 Ma; and 2) the overlying Citronelle Formation near its type locality in southern Alabama is therefore late Miocene or younger.

The new asteroid species Sclerasterias zinsmeisteri (Asteriidae), Paragonaster clarkae, Tesselaster clarki (both Goniasteridae), and the new ophiuroid species Ophiura hendleri (Ophiuridae) are described from the late Eocene La Meseta Formation at Seymour Island, Antarctic Peninsula. The arm tip of an apparently new genus of the Oreasteridae is too incomplete to assign at the generic level. Other La Meseta asteroid species have been described elsewhere. Six of seven recognized stelleroid genera and all represented families survive, and differences between new species and existing congeneric species are subtle. Thus, the La Meseta fauna was similar to living faunas in basic composition.

Among La Meseta asteroids, Zoroaster aff. Z. fulgens and Ctenophoraster downeyae are known from numerous specimens; fossils of the other species are comparatively uncommon and given the uncertainties of sampling, further taxa might await discovery at Seymour Island. Although the Paxillosida is known from Jurassic rocks, fasciole-bearing, semi-infaunal genera are first known from Cretaceous deposits, and Astropecten and Astropecten-like Ctenophoraster are first recorded from Cenozoic rocks. Zoroaster and Tesselaster are only known from deep water settings today, although they are found in the La Meseta. Ophiura hendleri, the only ophiuroid recognized to date from the La Meseta, occurs singly, in small groups, and in Paleozoic-type ophiuroid-rich beds.

An early Devonian graptolite fauna is described from Lila and Huiku sections in Southwest Yunnan, China. Three graptolite biozones are recognized, which in ascending order are: Monograptus uniformis Biozone, M. hercynicus Biozone and M. falcarius Biozone. Six species are described in this paper: Monograptus uniformis Příbyl, M. aequabilis (Příbyl), M. microdon Richter, M. hercynicus Perner, M. falcarius Koren, and Abiesgraptus sp.

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.

The ichnogenus Curvolithus Fritsch, 1908, originally described from the Ordovician of the Prague Basin, typically comprises ribbonlike or tonguelike, flattened, endostratal traces with three rounded lobes on the upper surface. However, considerable confusion persists regarding the ichnotaxonomic status and diagnostic features of its ichnospecies. The type specimens of this ichnotaxon, overlooked in most subsequent reports, are redescribed herein. Curvolithus multiplex Fritsch, 1908, the type species, is retained for specimens with a trilobate upper surface and a quadralobate lower surface, in contrast to the criteria adopted by subsequent authors. The other ichnospecies originally proposed from the type locality, C. gregarius Fritsch, 1908, actually consists of a series of grouped parallel scratch marks forming ridges and should be removed from Curvolithus. Subsequently, four ichnospecies were defined: C.? davidis Webby 1970; C. annulatus Badve and Ghare 1978; C. aequus Walter et al. 1989; and C. manitouensis Maples and Suttner 1990. Curvolithus? davidis shows the typical trilobation of Curvolithus apparently in its lower surface, but the morphology of the upper surface is uncertain. Accordingly, it does not warrant ichnospecific assessment, and is regarded as a nomen dubium. The nature of the annulations on the trilobate upper surface of C. annulatus is unclear, and this ichnospecies is also best considered as a nomen dubium.Curvolithus aequus has a bilobate lower surface and probably represents washed out specimens of Didymaulichnus. Finally, C. manitouensis comprises specimens with a smooth, trilobate upper surface and a smooth, quadralobate lower surface, and is best regarded as a junior synonym of C. multiplex. Curvolithus multiplex has been used incorrectly for Curvolithus with a trilobate upper surface and a trilobate to unilobate lower surface. The new ichnospecies, Curvolithus simplex, is proposed herein for such traces. Curvolithus is interpreted as a locomotion trace (Repichnia) of endostratal carnivores, possibly gastropods, flatworms, or nemerteans. Curvolithus is a component of the Cruziana ichnofacies in shallow-marine facies, either of normal salinity or slightly brackish, in the latter case typically associated with fan deltas.

Tidal rhythmites of the Tonganoxie Sandstone Member (Stranger Formation, Douglas Group) at Buildex Quarry, eastern Kansas, contain a relatively diverse ichnofauna. The assemblage includes arthropod locomotion (Dendroidichnites irregulare, Diplichnites gouldi types A and B, Diplopodichnus biformis, Kouphichnium isp., Mirandaichnium famatinense, and Stiaria intermedia), resting (Tonganoxichnus buildexensis) and feeding traces (Stiallia pilosa, Tonganoxichnus ottawensis); grazing traces (Gordia indianaensis, Helminthoidichnites tenuis, Helminthopsis hieroglyphica); feeding structures (Circulichnis montanus, Treptichnus bifurcus, Treptichnus pollardi, irregular networks), fish traces (Undichna britannica, Undichna simplicitas), tetrapod trackways, and root traces. The taxonomy of some of these ichnotaxa is briefly reviewed and emended diagnoses for Gordia indianaensis and Helminthoidichnites tenuis are proposed. Additionally, the combined name Dendroidichnites irregulare is proposed for nested chevron trackways. Traces previously regarded as produced by isopods are reinterpreted as myriapod trackways (D. gouldi type B). Trackways formerly interpreted as limulid crawling and swimming traces are assigned herein to Kouphichnium isp and Dendroidichnites irregulare, respectively.

Taphonomic analysis suggests that most grazing and feeding traces were formed before the arthropod trackways and resting traces. Grazing/feeding traces were formed in a soft, probably submerged substrate. Conversely, the majority of trackways and resting traces probably were produced subaerially in a firmer, dewatered and desiccated sediment.

The Buildex Quarry ichnofauna records the activity of a terrestrial and freshwater biota. The presence of this assemblage in tidal rhythmites is consistent with deposition on tidal flats in the most proximal zone of the inner estuary, between the maximum landward limit of tidal currents and the salinity limit further towards the sea.

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.

Four new species of cyathaspidid extend the range of the genus Poraspis back into the Late Silurian and indicate that the Canadian arctic was its center of origin. Poraspis heintzae n. sp., P. cracens n. sp., P. thules n. sp. and P. parmula n. sp. also increase the known geographic range of the genus which had previously been reported only from the District of Mackenzie (NWT, Canada), Spitsbergen, western and eastern Europe. The identification of P. sericea from the upper member of the Peel Sound Formation substantiates correlation of this interval with the crouchi zone of the Anglo-Welsh Borders, and provides another rare example of a species common to the Canadian arctic and European successions.

Borings of the ichnogenus Gastrochaenolites have been found in limestone cobbles of the Morrowan (Early Pennsylvanian) Cane Hill Member of the Hale Formation in northwestern Arkansas. They were likely excavated by lithophagid bivalves, thus extending the earliest record of obligate bivalve boring back from the Triassic into the upper Paleozoic. These borings are herein referred to as G. anauchen n. ichnosp. Lithophagid borings may be rare in the upper Paleozoic because of the absence or scarcity of suitable substrates, such as scleractinian corals or carbonate hardgrounds. Additional upper Paleozoic bivalve borings will likely be discovered in other carbonate-rich rocky shore deposits.

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.

The taxonomy of the European stenonoid horses is revised using multivariate statistical techniques in this paper. The objectives are: to identify the taxonomic status of this group; to revise the specific and subspecific diagnoses, and the valid taxa; and to analyze their paleoecology and evolution. We conclude that: 1) there are six species among the Plio-Pleistocene European stenonoids: Equus major Depéret, in Delafond and Depéret 1893, ex Boule; Equus livenzovensis Bajgusheva, 1978; Equus stenonis Cocchi, 1867; Equus senezensis Prat, 1964; Equus altidens von Reichenau, 1915; and Equus sussenbornensis Wüts, 1901; 2) There are seven subspecies, three of E. stenonis, two of E. senezensis, and two of E. altidens; 3) There are two monophyletic groups according to the “neighbor-joining method,” one composed of the middle-to-small-size species, and the other of the biggest ones; 4) There is a trend toward decreasing body size through time in stenonoid horses. This trend, that follows the inverse direction of Cope's rule, can be related to the climatic-environmental changes that occurred from the middle Villafranchian to the early Galerian; 5) Large stenonoids were recorded in the middle Villafranchian and were associated with open and dry habitats (steppes), whereas the small ones lived in more closed and wet habitats (savanna-mosaic, woodlands) from late Villafranchian to earliest Galerian.