A well-preserved radiolarian fauna reported from the Changxing Formation in the Meishan D Section, Changxing, Zhejiang, China, mainly includes abundant Entactinia itsukaichiensis, Grandetortura nipponica, Copicyntra robustodentata, Lepingosphaera stauracanthus, and a few Entactinia meishanensis n. sp., Entactinia? sp., Entactinosphaera cimelia, Triaenosphaera sp., Tetragregnon sp., Paracopicyntra ziyunensis, Copicyntroides sp. cf. C. asteriformis, Copicyntroides sp., and Ishigum trifustis, with the conodont Neogondolella subcarinata Zone. One new species, Entactinia meishanensis, is described in this paper. This radiolarian fauna is characterized by low abundance and low diversity, and apparently occurred in a water depth of 150–200 m.

A large sample of excellently preserved ammonites from concretions concentrated at a single horizon near the base of the Macdougall Point Member of the Christopher Formation (Aptian–Albian age; Early Cretaceous) is the basis for recognizing a new species of the boreal ammonite genus Pseudogastroplites (P. draconensis). The dimorphic nature of the genus is established, two variants are recognized (P. draconensis var. robusta and P. draconensis var. gracile), and the generic diagnosis is emended. Retention of the genus Pseudogastroplites Jeletzky, 1980 as distinct from Gastroplites McLearn, 1930 is proposed. The concretions also yield Pseudopulchellia flexicostata (Imlay, 1961), inoceramid bivalves, fish remains, and a palynological flora, and are dated as late middle Albian.

A new synziphosurine (Chelicerata:Xiphosura) is described from the Late Llandovery (Silurian) Konservat-Lagerstätte of Waukesha, Wisconsin, USA. Venustulus waukeshaensis n.gen. and sp. is characterized by a semicircular carapace with a slightly procurved posterior margin lacking genal spines and an opisthosoma composed of 10 freely articulating segments, divided into a preabdomen of seven segments with blunt pleurae and a postabdomen of three segments lacking pleurae. The tail spine is short and styliform. This is the earliest known unequivocal synziphosurine, extending their fossil record from the Wenlock to the Llandovery, and only the second species to be described with prosomal appendages; the presence of six pairs (a pair of chelicerae and five pairs of walking legs) contrasts with the seven in the synziphosurine Weinbergina opitzi, but is comparable to the number in modern horseshoe crabs. V. waukeshaensis n. gen. and sp. is not assigned to a family here pending a wider revision, but it bears most resemblance to the Weinberginidae.

Previously unstudied and earlier-known specimens have revealed the wide cephalic doublure and median ventral suture in Stenopilus; the hypostome is unknown but was probably natant. The cranidium of S. pronus differs from that of the type species S. intermedius in its greater length and convexity; the pygidium is known from rare complete specimens. These two species are present in Quebec, Newfoundland, and Vermont. They are differentiated from Leiocoryphe, which also had a highly effaced cephalon. Relationships remain problematic between these two genera and others currently placed in Plethopeltidae. An enrolled specimen of S. pronus is refigured and the anatomy and mode of life considered as that of a vagrant benthic animal rather than one that lived in a burrow as previously thought.

The integration of Geographic Information System (GIS) methodology within a phylogenetic and statistical framework provides a background against which to evaluate the relationship between biogeographic changes and evolution in the fossil record. A case study based on patterns in Middle and Late Devonian phyllocarids (Crustacea) illustrates the usefulness of this integrated approach. Using a combined approach enhances determination of rates of biodiversity change and the relationship between biogeographic and evolutionary changes. Because the interaction between speciation and extinction rates fundamentally determines biodiversity dynamics, and speciation and extinction rates are influenced by the geographic ranges of component taxa, the relationship between biogeography and evolution is important. Furthermore, GIS makes it possible to quantify paleobiogeographic ranges.

Phylogenetic biogeography resolved patterns of both vicariance and geodispersal and revealed that range expansions were more abundant than range contractions in Devonian phyllocarids. In addition, statistical tests on GIS-constrained species ranges and evolutionary-rate data revealed a relationship between increasing species' ranges and increases in both speciation and extinction rates. Extinction rate, however, increased more rapidly than speciation rate in the phyllocarids. The pattern of extinction rate increasing faster than speciation rate in the phyllocarids may illuminate aspects of the Late Devonian biodiversity crisis in particular, and protracted biodiversity crises in general.

The xanthoid genus Xanthilites Bell, 1858 is herein restricted to contain only the type species X. bowerbanki and possibly a second species. Xanthilites sensu stricto, Pulalius, Tumidocarcinus, Paratumidocarcinus, and Baricarcinus are placed within the Tumidocarcinidae new family within the Xanthoidea. It is hypothesized that the Carpiliidae, Platyxanthidae, Tumidocarcinidae new family, Zanthopsidae, and at least some subfamilies of the Eriphiidae form a natural group and may belong to a discrete superfamily, based upon paleontological and neontological evidence. The earliest documented occurrence in the fossil record for the xanthoid Platyxanthidae is in Eocene rocks, with the referral herein of a fossil species to the family. The two related families, Eriphiidae and Platyxanthidae, are difficult to distinguish from one another in fossil specimens; diagnoses which take into account preservable characters are provided. Moreover, based upon morphological features the Eriphiidae as currently defined may comprise at least two families. Revision of Xanthilites has resulted in two new genera, Jakobsenius and Rocacarcinus, erected for Xanthilites? cretacea and X. gerthi respectively, both placed within the extinct Palaeoxanthopsidae. The common ancestor of at least some families currently referred to the Xanthoidea may lie within the Palaeoxanthopsidae, which may have embraced “pre-adapted survivor” taxa, surviving the end-Cretaceous extinction event. Goniocypoda tessieri is confirmed as a member of the Hexapodidae, extending the range of that family into the Cretaceous; however, the family is not a likely candidate for embracing the ancestral xanthoids. The illustrated specimen of Menippe frescoensis retains a barnacle epibiont, very rare in the fossil record of decapods.

Species of Trophon Montfort, 1810 are well known from Tertiary rocks exposed over a wide area of Patagonia. All nominal species referable to the genus were revised and, where necessary, synonymized. Valid species were redescribed and reillustrated, based on type material and additional material collected at other localities ranging from Península Valdés to south of the mouth of the Santa Cruz River (along the Atlantic coast of Patagonia) to Lake Pueyrredón (along the foothills of the Andes). Of the 17 nominal species, only six are considered valid, i.e., Trophon sowerbyi new name (replacement for Fusus patagonicus Sowerby, 1846 in Darwin non d'Orbigny), Trophon santacruzensis Ihering, 1897, Trophon camachoi new species, Trophon leanzai Brunet, 1997, Trophon contortus Brunet, 1997, and Trophon inornatus Pilsbry, 1897.

The Cambrian fauna of Massachusetts, characterized by Paradoxides (Hydrocephalus) harlani, is poorly preserved. Better-preserved specimens, occurring within the stratigraphic range of this trilobite in southeastern Newfoundland and Morocco, provide a better understanding of such taxa to widen the scope of correlation. The paradoxidid-bearing Braintree Formation has revealed three trilobite species to add to those recently recorded. They represent Ellipsocephaloidea not previously recognized in this Massachusetts sequence, namely Protoleninae by Hamatolenus (H.) aff. H. (H.) marocanus and H. (Myopsolenus) aff. H. (M.) magnus and Ellipsocephalidae by Holocephalina aff. H. levis, thus strengthening faunal relationships with midshelf Cambrian sequences in Morocco and Spain. Reinterpretations of Agnostida, based on Newfoundland material associated with P. (Hydrocephalus) harlani, indicate that Condylopyge eli and Kiskinella cf. K. cristata signify a stratigraphic position for part of the Massachusetts sequence a little above the first appearance of Ovatoryctocara granulata. Appearance of this latter species is under review as the basal boundary of a global Cambrian stage, and is below the sequence break within the Chamberlain's Brook Formation in Newfoundland marked by the Easter Cove Blister Bed. The problem of differentiating species with numerous variable growth stages is highlighted in the ontogenies and stratigraphic ranges of P. (H.) harlani and P. (Plutonides) haywardi and emphasizes the importance of cephalic morphology in paradoxidid classification. Details of the holotypes of Agraulos quadrangularis and Braintreella rogersi and Czech topotypes of Agraulos ceticephalus supplement generic and specific characters poorly understood, especially those involving proportional differences between tectonically/taphonomically flattened examples and undistorted high-relief specimens.

Thirty-four crinoid species, including four new species, are reported from the Nada Member of the Borden Formation in eastern Kentucky. The dominant crinoid group is monobathrids (18 species), but diplobathrids, disparids, cladids, and flexibles are also present. The four new species are the camerates Blairocrinus protuberatus, Uperocrinus acuminatus, and Aorocrinus nodulus, and the cladid Atelestocrinus kentuckyensis. The majority of the species in this fauna were previously known from what has traditionally been considered the “upper part” of the Burlington Limestone in the Mississippi River Valley and what is now recognized as the Burlington Pelmatozoan Assemblage III. The current study confirms the conclusion of Lane and DuBar (1983) that the Nada is middle Osagean in age, being deposited earlier than the well-documented Borden delta crinoid assemblages of north-central Kentucky and Indiana. The middle Osagean age of the fauna indicates a previously unrecognized unconformity between the Nada and the overlying Meramecian-age Renfro Member of the Slade Formation. In addition, this is the first well-documented middle Osagean fauna from a siliciclastic facies in North America. The dominance by camerate crinoids is enigmatic, but may be related to either a low rate of sedimentation or greater larval dispersal abilities.

A small early Late Viséan (Mississippian) ammonoid assemblage with Entogonites saharensis new species and Goniatites lazarus new species is described from the eastern Anti–Atlas of Morocco, being the first African record of Entogonites. The family Goniatitidae is a typical Lazarus taxon, which, after a gap representing approximately 10 million years, reappears in the fossil record. The genera Entogonites and Goniatites have a wide paleogeographic distribution (northwest Laurentia, northern and southern Variscides, north Gondwana). This indicates ammonoid cosmopolitism at the genus level at the end of the middle Viséan, before late Viséan ammonoid provinces formed. Entogonites with tetrangularly coiled juvenile whorls and with a low aperture probably had a planktonic life- style.

In North America, the ammonoid Uraloceras Ruzhentsev occurs in Cisuralian (Lower Permian) strata of the northern Yukon Territory, eastern Alaska, Ellesmere Island, southern British Columbia, and Nevada. From Sakmarian to Kungurian, species of Uraloceras occupied a narrow belt in the Northern Hemisphere (Boreal paleogeographical realm) that extended from the northern and northwestern margin of the Pangaean supercontinent southward to regions of present-day Siberia, the Ural Mountains, as well as Nei Monggol and Tibet. In the Yukon Territory, Nevada, Nei Monggol, and possibly Tibet, the association of Uraloceras with typically equatorial perrinitid ammonoids may represent a transition from “Boreal” occurrences in high latitudes to “Tethyan” of lower latitudes. Uraloceras nevadense n. sp. is described herein from Nevada and eastern Alaska.

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.

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.