Fossil horseshoe crabs are rare, and new discoveries have the potential for providing important taxonomic and biostratigraphic information. The superfamily Limulacea Zittel, 1885, embraces the lineal ancestors of the modern genera, including Limulus Müller, 1785, within the Limulidae Zittel, 1885. The geologically oldest of the limulaceans are arrayed within the late Paleozoic Paleolimulidae Raymond, 1944. The first discovery, as well as all authentic specimens, of fossil paleolimulids have been from the Late Paleozoic rocks of Kansas and Illinois. This paper not only describes a new genus and species of horseshoe crab but also records the first occurrence of the family in north-central Texas, and clarifies placement of taxa within the Paleolimulidae.

Dianchungosaurus lufengensis was erected on the basis of fragmentary isolated jaw elements (a left premaxilla and left and right partial lower jaws) from the Lower Lufeng Formation (Lower Jurassic) of Yunnan Province, China. Yang referred Dianchungosaurus to the Heterodontosauridae (Ornithischia, Ornithopoda), as several features appeared to indicate affinity with the southern African genus Heterodontosaurus. However, reexamination of the type material demonstrates that the holotype specimen of Dianchungosaurus represents a chimaera of prosauropod dinosaur and mesoeucrocodylian remains: the mesoeucrocodylian premaxilla is distinctive and allows the genus to be diagnosed on the basis of several autapomorphic features. Revision of this genus thereby invalidates the only reported occurrence of a heterodontosaurid dinosaur from Asia.

Skeletonized protists (or protoctists) appear as body fossils in the late Neoproterozoic and the lower Cambrian (e.g., Allison and Hilgert, 1986; Lipps, 1992; Culver, 1994; Porter et al., 2003) and are well known from the post-Cambrian fossil record. However, molecular data and biomarkers of groups such as ciliates and foraminiferans indicate a long Precambrian history unrecorded by fossils, and also suggest that foraminiferans were important components of Neoproterozoic protistan communities (e.g., Summons et al., 1988; Wright and Lynn, 1997; Lipps, 2003; Pawlowski et al., 2003). The recent discovery of agglutinated microfossils interpreted as foraminiferans from the Neoproterozoic of Uruguay (Gaucher and Sprechmann, 1999) supports the inferences made from molecular data. Although foraminiferans are known for certain since the earliest Cambrian (e.g., McIlroy et al., 2001), their diversity and variability during the Cambrian is limited to a few agglutinated unilocular genera (e.g., Lipps, 1985; Culver, 1991, 1994; Cope and McIlroy, 1998; Zhigulina, 1999; McIlroy et al., 2001). Among these, Platysolenites Pander, 1851 is one of the best known genera because it has a wide distribution and high abundance in lower Cambrian sediments, especially those of Baltica and Avalonia (e.g., Rozanov, 1983; Lipps and Rozanov, 1996; McIlroy et al., 2001). Whether Platysolenites has an affinity with the foraminifera has been questioned by some authors (e.g., Eichwald, 1860; Rozanov, 1983; Brasier, 1989b), but the similarity of its morphology and wall structure to the foraminiferan genus Bathysiphon Sars, 1872 (e.g., Glaessner, 1978), and the presence of proloculi in Platysolenites (e.g., McIlroy et al., 2001) is strong evidence in favor of an affinity with the foraminifera. It should be emphasized that the preservation of proloculi in Platysolenites is rare, reported only in a few cases (McIlroy et al., 1994, 2001; Lipps and Rozanov, 1996) prior to this one.

Permian ammonoids with perrinitids are reported from Kalpin and Qiemo areas in Xinjiang, northwest China. Nine species, representing nine genera: Parapronorites, Propinacoceras, Medlicottia, Eothinites, Agathiceras, Prostacheoceras, Metaperrinites, Perrinites, and Tauroceras are described from the Yesanggang Formation of the Qiemo area. Strong uniformity in Permian ammonoid biostratigraphy and provincialism between Xinjiang and Pamir is suggested.

Articulated scleritomes of the chancelloriids Archiasterella fletchergryllus new species and Chancelloria cf. eros Walcott, 1920 are described from the Early Cambrian (Branchian) Sekwi Formation, Mackenzie Mountains, Northwest Territories, Canada. Early diagenetic, microbially mediated lithification has resulted in unusual three-dimensional preservation of the body surface, which potentially allows consideration of the evolutionary affinities of these enigmatic organisms. Sclerites are mounted on short stalks of the integument, connected to the undersurface of the central disc, and are external to the body surface.

Sponges from Permian beds in West Texas have been known from the early pioneer publication on the Guadalupian fauna by Girty (1908) and the later works by King (1933, 1943), Finks (1960, 1983, 1995), and Rigby et al. (1998). The sponge described here is perhaps the youngest hexactinellid known from the region. It was collected from the Reef Trail Member, the uppermost member of the Upper Guadalupian Bell Canyon Formation, from fault-isolated exposures of the formation in the Patterson Hills (Fig. 1) in the southwestern part of Guadalupe Mountains National Park, south of El Capitan and Guadalupe Peak.

The present study is based on extensive sampling from an olistolith located near Castle Peak in the Taseko Lakes map area (British Columbia, Canada). The fauna is diverse and well preserved and similar to that illustrated from Monte Cetona in Italy by Fucini (1903).

The rugose linoproductoid Permundaria Nakamura, Kato, and Choi, 1970 was stated to be a “poorly understood genus” in the new Brachiopoda Treatise (Brunton et al., 2000, p. 563). It is an uncommon genus confined to the Middle–early Late Permian Tethys Sea, and reports of it have usually been based on only a small number of specimens. In this study, some 30 samples of Permundaria were recovered from the Bera South beds (Wordian, Middle Permian) of the Bera Formation, Pahang, Peninsular Malaysia. The material represents a new species of the genus, which is here described. Its new morphological information enables taxonomic revision of this often misunderstood genus, and helps to clarify some confusion among related, or superficially similar, linoproductoid genera.

Although fossilized teeth of sharks and rays are common elements in Eocene nearshore marine sediments of the southeastern United States (Parmley and Cicimurri, 2003 and references within), fossil remains of chimaeroid fishes are unknown from this region. Here we provide the first report of an Eocene chimaeroid fish from the southeastern United States, consisting of a partial, well-preserved left mandibular tooth plate recovered from central Georgia.

The genus Mesacridites Riek, 1954 is so poorly known that Carpenter (1992) considered it as Neoptera order uncertain. Riek (1954) assigned it to the paraphyletic group Protorthoptera, within the family Sthenaropodidae Handlirsch, 1906, a family later synonymized by Burnham (1983) with the Geraridae Scudder, 1885. Sharov (1962, 1991) assigned it to the order Paraplecoptera within the superfamily Liomopteridea, which is within the Protorthoptera in Carpenter's system.

Foraminiferans belonging to the genus Bathysiphon G. O. and M. Sars in G. O. Sars, 1872 are among the largest fossil protists ever described, some species having tubular tests exceeding 100 mm in length (Miller, 1995). One species, Bathysiphon aaltoi Miller, 1986, from mid-Cretaceous fine-grained turbidites within the Franciscan Complex of northern California, may be the largest fossil foraminiferan ever collected with an estimated test length of approximately 150 mm (Miller, 1991, 1997). Species of comparable size are known from the modern deep-ocean floor (where they often rival or surpass the size of co-occurring metazoans) and are an important component of deep-sea benthic ecosystems (Gooday, 1983; Gage and Tyler, 1991; Gooday et al., 1992).

In addition to ammonoids and conodonts, the enigmatic and poorly understood “flat clams” belonging to the genera Enteropleura Kittl, 1912, Daonella Mojsisovics, 1874, Halobia Bronn, 1830, and Monotis Bronn, 1830 have proven to be of biochronologic value through the Middle and Upper Triassic (e.g., Silberling and Nichols, 1982; Brack and Rieber, 1993; Campbell, 1994; McRoberts, 1997). These “flat clams,” many belonging to the family Halobiidae, can be extremely abundant in the marine Triassic rocks of the former Panthalassic Ocean and especially the Tethyan Seaway, where many of these species were first described. Their widespread nature and high speciation rates make these bivalves exceptional biochronologic indicators, especially when integrated with the temporal distribution of other, more conventional indices such as ammonoids and/or conodonts. We describe and name a poorly documented halobiid species, Enteropleura jenksi n. sp., from the latest middle Anisian and therefore provide a robust correlation datum for the Shoshonensis Zone.

The last 15 years of field work along the beaches and bluffs of the Colville River, on Alaska's Arctic Coastal Plain, have produced a diverse record of high-latitude dinosaurs. Seven families and eight genera are documented with several other families and genera possibly being represented by less diagnostic remains and only a few scattered elements (Table 1; Nelms, 1989; Gangloff, 1994, 1998; Fiorillo et al., 1999; Fiorillo and Gangloff, 2000, 2001). Virtually all of the common major groups of theropods and ornithopods typical of the Late Cretaceous of northern North America are present. Most of the skeletal remains are found in rocks assigned to the Prince Creek Formation of the Colville Group (Detterman et al., 1963, 1975; Phillips, 1990). The diversity of the dinosaur record in Alaska has been significantly increased with the discovery of abundant tracks and trackways along the North Slope and Arctic Coastal Plain over the last six years. The majority of the ichnofossil record is contained in various terrestrial coal-bearing rocks assigned to the Early Cretaceous Nanushuk Group (Ahlbrandt et al., 1979). The dinosaur biozone spans the upper part of the Nanushuk group and all of the Colville Group, ranging from the mid to Late Cretaceous (Albian to Maastrichtian; Mull, 1985). The already diverse and abundant record of dinosaur skeletal fossils was increased by the discovery in 1999 of the first evidence of pachycephalosaurs from this region (Fig. 1). This taxon is now represented by a nearly complete left squamosal and the contiguous, posterior, basal part of the dome. The highly thickened bone with characteristic prismatic internal structure accompanied by the distinctive ornamentation diagnostic of this group allows for an unequivocal identification to the subfamily level. The specimen (UAM # AK-493-V-001, Fig. 2.2) is most of the left squamosal and includes a portion of a thickened dome. The specimen is bounded on three sides by parted sutures interpreted as representing the contacts with the quadrate, exoccipital, and the narrow descending portion of the parietal bone (see Fig. 2.2, 2.4). The remaining margin exhibits a broken surface that reflects the polygonal prismatic internal structure of a part of the parietal-frontal dome. The sutures are well preserved and show little or no evidence of fluvial abrasion or weathering due to subaerial exposure prior to burial.

Permian shallow marine strata are widely distributed in the Southern Kitakami Massif, Northeast Japan. They yield many marine fossils and have been well studied both stratigraphically and biostratigraphically. However, the geological age of the upper part of the Permian in the Tassobe district, located in the northern part of the Southern Kitakami Massif (Fig. 1), is still an unsettled question. The Permian is divided into the lower Tassobe and upper Sotokawame Formations (Okuyama, 1980; Yoshida et al., 1992). Early Permian (Sakmarian–Artinskian) fusulinoideans have been known from the middle to lower-upper part of the Tassobe Formation (Hirokawa and Yoshida, 1956; Saito, 1968; Yoshida et al., 1992), whereas no age-diagnostic fossils have been found from the overlying Sotokawame Formation. In the course of the geologic survey of the Permian, we collected two ammonoid fossils from the lower part of the Sotokawame Formation, which can provide us a basis for stratigraphic correlation. This paper describes these ammonoids and discusses their stratigraphic and biogeographic significance.

Our understanding of the Cretaceous ammonite succession of Peru is mainly based on the reference work of Benavides Cáceres (1956) that updates the descriptive paleontological papers by Gabb (1877), Sommermeier (1910), and Knechtel et al. (1947), among others. New fossil collections made in the course 1995 and 1999 in northern and central Peru provide the basis for a revision of the Albian ammonite faunas of this country. In contrast to our predecessors, our collections are based on sections that have been sampled bed by bed.

Eriaster ibexensis n. gen. and sp., from the Ibexian (Lower Ordovician) of Utah, is the oldest-known body-fossil taxon of the class Asteroidea. Although important features are not preserved, the external form of E. ibexensis is suggestive of certain living asteroids and unlike approximately coeval somasteroids. The similar ages of Eriaster and the oldest-known somasteroid challenge the candidacy of the latter as basal to asteroids.

Trace fossils assigned to Asteriacites have been recovered from strata as ancient as Lower Cambrian. Asteriacites from younger strata are considered to represent resting traces of asterozoans. Mode of formation of early representatives is problematic; however, their simple existence raises the possibility of extended pre-Ibexian asterozoan evolution, which could explain the morphological disparity found among the earliest-known body-fossil asterozoans.

Jurassic marine reptiles are best known from the study of European Jurassic collections. The record of these reptiles encompasses most of the period, but that of Aalenian–Bathonian rocks is quite incomplete (Andrews, 1913; Brown, 1981; Buffetaut, 1982; Godefroit, 1994; Bardet, 1995; O'Keefe, 2001; McGowan and Motani, 2003). South American marine reptiles of the early Middle Jurassic are especially significant because they contribute to fill this gap of taxonomic and paleogeographic information (Fernández, 1994, 1999, 2003; Spalletti et al., 1994; Gasparini, 1997; Gasparini et al., 2000).

Reading the voluminous lists of synonymy of the taxa described in this report, it may seem useless at first glance to add yet more descriptions and potentially continue an already confused situation. However, as taxonomists know, long lists of synonymy may indicate that certain taxa serve as a “garbage-can” for specimens which lack distinctive morphological features. An example of a “garbage-can taxon” is the pseudorthoceratid genus Mooreoceras Miller, Dunbar, and Condra, 1933, which originally was very broadly defined and therefore comprised about 40 species.