Paleobiogeographic patterns of decapod crustaceans from the Southern Hemisphere, based upon 441 species-level records arrayed in 154 genera, document global patterns of distribution that can be compared to those previously published on decapods from the North Pacific and Central American regions. All known records of decapods from the Southern Hemisphere spanning the Early Triassic to Pleistocene have been compiled, nearly all have been personally verified, and patterns of origin and distribution have been interpreted. Interchange between hemispheres, including amphitropical and bipolar distributions, are recognized from Jurassic to post–Miocene time. The high southern latitudes was a site of origin of several generic-level taxa during the Jurassic through Eocene and many of these taxa have been identified in subsequent times in lower latitude regions in shallow- and deepwater environments in both hemispheres. The isolation of Antarctica due to ocean currents significantly diminished the role of the high southern latitudes as an area of origin for decapods. The Tethys was an important dispersal pathway for decapods during the Cretaceous through early Miocene. Endemism was high during the Eocene, similar to the North Pacific and Central America. The magnitude of the Cretaceous/Paleogene extinction event on the Southern Hemisphere decapod fauna was not profound; most Cretaceous extinctions seem to have occurred well before the end of the Cretaceous, and 85% of the Cretaceous families are known from the Paleogene in the Southern Hemisphere taxa.

The pre-Pleistocene fossil record of sturgeons (family Acipenseridae) from North America is reviewed based on a survey of reports in the literature and firsthand examination of specimens in museum collections. We provide a redescription of the only known specimen of †Protoscaphirhynchus squamosus (Late Cretaceous, Montana), a very poorly preserved specimen for which few morphological details can be determined. Three taxa described as species of the genus Acipenser from North America (†A. albertensis, †A. eruciferus, and †A. ornatus) were described based on isolated and fragmentary remains, and are here considered to be nomina dubia. The earliest reported remains of North American sturgeons are from the Late Cretaceous (Santonian to Campanian Milk River Formation). There is a relatively continuous record, with the exception of the Eocene and Oligocene, in which there are few (potentially in the Eocene) or no (Oligocene) known specimens available in collections. We have found that nearly all specimens are best regarded as Acipenseridae indeterminate genus and species due to their fragmentary preservation and lack of preserved diagnostic characters.

New collections rich in agnostoid trilobites were recovered from Lower Ordovician strata of the southern Montagne Noire, France. The faunas occur in the La Gardie/Val d'Homs, Saint–Chinian, La Maurerie, and Landeyran formations, coinciding with deposition in muddy outer-platform settings. Many previously described species are revised and their stratigraphic ranges emended. The studied agnostoids include Geragnostus cf. sidenbladhi (Linnarsson), G. aff. sidenbladhi, G. crassus Tjernvik, G. splendens (Holub), G. cf. explanatus Tjernvik, G. boutouryensis Howell, G. occitanus Howell, Geragnostus sp., Trinodus corpulentus Howell, Homagnostoides ferralsensis (Munier-Chalmas and Bergeron), Corrugatagnostus coulobresensis n. sp., Corrugatagnostus sp., Leiagnostus miqueli Sdzuy, and Leiagnostus sp. The record from the upper part of the Saint–Chinian Formation suggests a late Tremadocian age, whereas an early Arenigian age is indicated for the upper part of the La Maurerie Formation. Although the agnostoid record generally reinforces the peri-Gondwanan character of the Lower Ordovician shelly faunas from the Montagne Noire, some agnostoid species are independent of specific paleogeographic boundaries.

Eocene ostracodes are described from the Japanese Islands for the first time. These ostracodes, from the Iojima Group in southwestern Japan, are represented by cosmopolitan and low- to midlatitudinal paleobiogeographic groups as well as an endemic group. Based on the distributions of selected genera, the ostracode fauna of the Iojima Group has tropical to subtropical affinities, affirming links with the Tethys Sea. Six species are described as new: Cytheropteron liue, Eopaijenborchella kamiyai, Eopaijenborchella okinoshimaensis, Ambtonia? matsubarai, Paracypris? kuritai, and Trachyleberis? funatsuensis.

Volutes are widely distributed in the Cenozoic record of Patagonia and Tierra del Fuego, where they are represented by the South American endemic genera Adelomelon Dall, 1906, Pachycymbiola Ihering, 1907, Odontocymbiola Clench and Turner, 1964, and Miomelon Dall, 1907. These taxa have been restricted to the southwestern Atlantic and southeastern Pacific Oceans from Tertiary times to the Recent, and since their earliest record in the ?Middle Eocene–Late Oligocene–earliest Miocene they have evolved adaptations to variations in water depth and temperature. These ecological adaptations were less marked for Adelomelon and Pachycymbiola, which have achieved a similar geographical pattern since the Tertiary, but they were strongly modified in Miomelon. In the Atlantic, Miomelon migrated southwards from the shallow and warm-temperate waters that it typically inhabited during the Tertiary, to deeper, colder waters of the Recent Magellanic Province and Subantarctic region, where it is restricted at present. A detailed discussion of the validity of Tertiary genus Proscaphella Ihering, 1907 herein concludes it to be a synonym of Miomelon Dall, 1907. Seven species are redescribed and illustrated: Adelomelon pilsbryi (Ihering), A. cannada (Ihering), A. (Pachycymbiola) ameghinoi Ihering, ?Pachycymbiola feruglioi (Doello Jurado), Miomelon gracilior (Ihering), M. dorbignyana (Philippi), and M. petersoni (Ortmann); and four new ones are described: Miomelon castilloensis, Pachycymbiola chenquensis, P. camachoi, and P. arriolensis.

The family Emuellidae Pocock, 1970 was established for Emuella Pocock, 1970 and Balcoracania Pocock, 1970 from the Lower Cambrian of South Australia. Based on their peculiar trunk tagmosis, emuellids have been interpreted as the sister group of all other trilobites with dorsal facial sutures, and classified as high as the ordinal level. Cladistic analysis with a range of exemplar taxa of the Olenellina and Redlichiina instead resolves the emuellids within the Redlichiina, with tagmosis into a prothorax and opisthothorax (“telosoma”) nonhomologous in olenellines and emuellids. A taxonomic revision of Australian species identifies Balcoracania flindersi as a junior subjective synonym of B. dailyi, whereas the two named species of Emuella are considered to be distinct. Balcoracania dailyi possesses up to 103 thoracic segments, the maximum number recorded in any trilobite.

Dolostones of the upper Piauí Formation, Parnaíba Basin, northern Brazil, preserve a rich and diversified invertebrate fauna of Morrowan to Desmoinesian age. Among bivalves, Heteroconchia (15 species) is the most diversified, followed by Pteriomorphia (11 species), and rare endobenthic species of the Palaeotaxodonta (three species). Eleven species of Pteriomorphia are described, including representatives of the genera Parallelodon?, Myalina?, Septimyalina, Caneyella?, Leptodesma (Leptodesma), L. (Leiopteria), Meekopinna?, Aviculopinna?, and Aviculopecten. A new combination, Etheripecten trichotomus, and the oldest member of the Anomiidae recorded, Pindorama nordestina n. gen. and sp., also are described. Details of muscle scars and hinge characters have been recovered for several taxa, thereby refining the knowledge for species diagnoses. Fossil beds in the Esperança and Mucambo dolostones reveal episodic burial of bivalves in life position. These are internally complex, multistory fossil concentrations recording background and episodic processes. Hence, those fossil concentrations show high degrees of time-averaging and poor paleoecological resolution (except for the bivalves preserved in situ).

The Germig Formation of the Tethyan Himalaya of southern Tibet contains an exceptionally abundant bivalve fauna which has been found in association with choristoceratid and psiloceratid ammonoids and spans the Triassic/Jurassic boundary. The bivalve fauna consists of 25 species, including four new species: Newaagia lanonglaensis, Persia hallami, Liostrea tibetica, and Ctenostreon newelli. The fauna comprises three biostratigraphically controlled bivalve assemblages: 1) an upper Rhaetian Palaeocardita–Krumbeckiella Assemblage including seven species; 2) a high diversity transitional Rhaetian-Hettangian Persia–Plagiostoma Assemblage with many as 19 species; and 3) a low diversity lower Hettangian Liostrea–Chlamys Assemblage containing three species. The transitional Rhaetian-Hettangian Assemblage is dominated by cementing species and exhibits a high degree of endemism. A large proportion of lower latitude and cementing taxa from the lower two levels may indicate that they inhabited shallow subtidal tropic or subtropic paleoenvironments.

Caribbean reefs underwent significant biotic change during the Late Oligocene and Early Miocene. This was a critical time in the evolution of the modern Caribbean fauna characterized by increasing endemism resulting from regional extinction of lineages that survive in the modern Indo-Pacific. An understanding of the dynamics and potential causes of the Oligocene/Miocene transition, however, is hampered by the relative lack of well-preserved Oligocene to early Miocene coral faunas in the Caribbean. Here we examine new exposures in the Culebra Formation of Panama that contain a well-preserved coral fauna of Early Miocene age. Taxonomic, stratigraphic, and paleoecologic study of the Culebra Formation exposed along the Gaillard Cut of the Panama Canal allows us to infer the paleoenvironments and reef coral communities from the Panama Canal Basin during this critical interval. The Culebra Formation consists of a deepening upward sequence with shallow-lagoon sediments at the base, overlain by fringing reef facies in the middle of the section, and open-shelf to bathyal facies at the top of the section. We recovered 31 species of reef corals from a combination of new and old collections. Comparison of our collections with other Late Oligocene to Middle Miocene reef coral assemblages confirms that there was a major faunal turnover after deposition of the Upper Oligocene Antigua Formation. This turnover consisted of a large number of extinctions followed by an increased rate of first occurrences so that regional diversity did not change appreciably. Improved stratigraphic resolution at this and other Caribbean localities is required to understand fully the dynamics of change during the Oligocene/Miocene transition.

A new fish fauna is described from the late Middle Miocene (Volhynian; early Sarmatian sensu lato) of Tsurevsky, North Caucasus, Russia. Ten taxa belonging to nine families are described, of which two may be new (Micromesistius sp., Bothus sp.), but not formally described awaiting better-preserved material. The predominant faunal element is Sardinella sardinites, including more than 42% of all investigated specimens. The paleoecological analysis reveals a semienclosed marine environment not far from the coast, characterized by shallow depths and a soft bottom. The sedimentological features of the deposits and the preservation of the specimens suggest that periodic oxygen minima affected the bottom waters, causing repeated hypoxic events, probably related to the decay of organic matter previously accumulated in the basin. Paleoenvironmental considerations of fish faunas from several Paratethyan localities suggest that marine waters characterized by a little shift in chemical composition (high alkalinity) filled up the entire basin during the Sarmatian.

In central Chiapas (southeastern México) the last occurrence of inoceramid bivalves was recorded in strata of the predominantly terrigenous Ocozocoautla Formation. The inoceramids are associated with foraminifers of the Gansserina gansseri Zone (Late Campanian to Early Maastrichtian). The described species are: Cataceramus? cf. barabini (Morton, 1834), Cataceramus? cf. subcircularis (Meek, 1876), Trochoceramus aff. costaecus (Khalafova, 1966), Trochoceramus nahorianensis (Kociubynskij, 1968), and Trochoceramus tricostatus n. sp. Based on the inoceramid and foraminifer species present, the assemblage is assigned to the Early Maastrichtian. This age is important because at this level most of the typical inoceramids globally disappeared. This is the first report of the genus Trochoceramus in México, which is a good index fossil for the Early Maastrichtian and has a cosmopolitan distribution.

Upper Tithonian (Jurassic) ammonites occur in the Chinameca Formation at Chinameca, southern Veracruz, eastern Mexico. The fauna includes Eopaquiericeras peraltai n. gen. and sp. and E. pazi new genus and species of the family Platylenticeratidae, Chinamecaceras maldonadoi n. gen. and sp. of the subfamily Aspidoceratinae, Veracruciceras ruizi n. gen. and sp. and V. myczynskii n. gen. and sp. of the subfamily Simoceratinae, Durangites zigzagcostatus n. sp., and representatives of Haploceras, Salinites, Kossmatia, and Andiceras. Kossmatia is the most abundant and biostratigraphically significant ammonite in the Chinameca fauna and its age significance and distribution in Mexico is discussed. In addition, a comparison of the suture lines of Kossmatia and the related older genus Lemencia indicates that they both belong to the Tithonian subfamily Richterellinae rather than the Upper Oxfordian–Kimmeridgian families Ataxioceratidae and Lithacoceratidae. The Chinameca ammonites have affinities with taxa of the same age from central and northern Mexico, Cuba, and the southern United States.

Upper Paleozoic Cephalopoda of west-central Patagonia are revised, based on reexamination of all available specimens and of most localities in Chubut Province, Argentina. Nautiloidea Orthocerida are represented by Sueroceras irregulare Riccardi and Sabattini, S.? chubutense (Closs), Sueroceras sp., and Mooreoceras zalazarense Sabattini and Riccardi and Pseudorthoceratidae gen. and sp. indeterminate; Nautilida by Amosiceras reticulatum new genus and species; and Ammonoidea Goniatitida by Glaphyrites taboadai new species and Glaphyrites sp. This fauna belongs to the Cisuralian Sueroceras irregulare and Mooreoceras zalazarense assemblage zones.

Eight new species of lichid trilobites representing five genera in three subfamilies, from the Avalanche Lake area of the southern Mackenzie Mountains, Northwest Territories, Canada, are described. The subfamily Lichinae is represented by Dicranopeltis n. sp. and the subfamily Platylichinae by the early Llandovery Platylichas infimus n. sp. The subfamily Trochurinae is represented by six species belonging to four genera. These are Acanthopyge (Lobopyge) sp. (Wenlock), the earliest known species of the genus Acanthopyge and subgenus Acanthopyge (Lobopyge), A. (L.) pristina n. sp. from the Glyptograptus persculptus Zone in the latest Ordovician, Dicranogmus lepidus n. sp., D. wilsoni n. sp. (both Wenlock), Dicranogmus n. sp. (Llandovery), and Radiolichas guttatus n. sp. (Wenlock).

Eighteen gastropod and seven bivalve species are reported from Eocene to Oligocene cold-seep carbonates in Washington State, USA. Four species are new (Niso littlei, Turrinosyrinx hickmanae, Xanthodaphne? campbellae, and Lurifax goederti), and 16 are described in open nomenclature. Previously unknown features of protoconch or prodissoconch morphology and/or shell microstructure are provided for Retiskenea statura (Goedert and Benham), Provanna antiqua Squires, Nuculana? aff. N. grasslei Allen, and Bathymodiolus willapaensis (Squires and Goedert). Modiolus (M.) willapaensis is placed within Bathymodiolus based on the elliptical-triangular shape of its juvenile shell, indicating that the divergence between vent/seep and whale/wood-fall inhabiting bathymodiolines took place at least 40 Ma. The first fossil species of the vent/seep genera Pyropelta (Pyropeltidae), Lurifax (family uncertain), and Catillopecten? (Propeamussidae) are reported. Niso (Eulimidae), Xanthodaphne, Turrinosyrinx, Benthomangelia (Turridae), Ledella (Nuculanidae), Tindaria? (Tindariidae), and Delectopecten (Pectinidae) are reported for the first time from fossil cold-seep assemblages. Larval developmental strategies are inferred from protoconch and prodissoconch morphologies in 14 species, which largely reflect the species' phylogenetic groups, as in modern vent and seep molluscs. The data presented here indicate that the radiation of toxoglossate turrids (Gastropoda) into deep water took place already in the Oligocene, and not in the Miocene as previously thought. Healed shell injuries and presumed naticid drill holes represent the oldest known fossil evidence of predation at cold-seeps.

Erosion of the upper Arkadelphia Formation by the Ouachita River in Hot Spring County, Arkansas, has revealed a diverse and abundant, late Maastrichtian chondrichthyan fauna representing at least 17 species: Squatina hassei, Ginglymostoma lehneri, Plicatoscyllium derameei, Ondontaspis aculeatus, Carcharias cf. C. holmdelensis, Serratolamna serrata, Squalicorax kaupi, Galeorhinus girardoti, Rhinobatos casieri, Ischyrhiza avonicola, Ischyrhiza mira, Sclerorhynchus sp., Ptychotrygon cf. P. vermiculata, Raja farishi, Rhombodus binkhorsti, and Dasyatis sp. All of these species are widely known from the Upper Cretaceous of North America. An extremely rare species, Schizorhiza cf. S. stromeri, currently known only from Mexico and Africa, is also present. The chondrichthyan remains occur almost entirely as teeth scattered by river activity across the surface of the marl and marly clay of the Arkadelphia Formation and can be collected from within localized accumulations of river sediments. Also present with the chondrichthyan remains are teeth from actinopterygians and reptiles as well as molluscan steinkerns, echinoid spines, and fragments of branching corals. This fauna expands the known geographic distribution of late Maastrichtian chondrichthyans in North America, and provides an important biostratigraphic connection between fauna of the Gulf Coastal Plain and Western Interior Seaway. It also supports the idea of a significant chondrichthyan turnover across the Cretaceous–Tertiary boundary.

Trilobites previously assigned to the Entomaspididae Ulrich in Bridge, 1931 are common in Laurentian strata assigned to the upper Sunwaptan Stage of the Upper Cambrian. Most species are poorly known, and typically only sparse cranidial data are available. Large silicified samples from the Lava Dam Member of the Notch Peak Formation, western Utah, contain three new species for which cranidia, librigenae, thoracic segments, and pygidia are known. the species permit clarification of the morphology and affinities of previously described taxa from elsewhere. They are referred to Notchpeakia n. gen. (type species: N. milleri n. sp.) which, in addition to the type includes N. taylori n. sp., N. notchpeakensis n. sp., N. cherrycreekensis n. sp., and N. varga (Westrop, 1986). the “entomaspidid” trilobites are assigned to the traditionally post-Cambrian Harpetidae Hawle and Corda, 1847.

The Lower Ordovician middle Beekmantown Group is a very thin carbonate platform succession on the northern New York Promontory that thickens north into the Ottawa aulacogen near Montréal. The Tribes Hill Formation (Rossodus manitouensis Zone) records the earliest Ordovician (late Skullrockian, late early Tremadocian) eustatic high that submerged Laurentia, and produced the lowest Ordovician sequence along the New York Promontory. These dolostones are succeeded in the Beekmantown, New York, area by late Tulean?–Blackhillsian transgressive systems tract quartz arenites of the lower Fort Cassin Formation (Ward Member). The “Fort Ann Formation” (middle Stairsian, upper Tremadocian) of the southern Lake Champlain lowlands (=Theresa Formation sandstones in the Ottawa graben) is absent at Beekmantown, and moderate Stairsian (late Tremadocian) eustatic rise apparently did not inundate the Beekmantown area after Skullrockian–Stairsian boundary interval offlap. Highstand carbonates of the upper Fort Cassin Formation [Sciota Member = “Spellman Formation” and “Ogdensburg Member” of the “Beauharnois Formation” in the Montréal area; designations abandoned] at Beekmantown yield diverse conodonts seemingly characteristic of the Oepikodus communis–Fahraeusodus marathonensis Zone (new). However, associated trilobites, particularly Carolinites tasmanensis (Etheridge, 1919), show a correlation with the upper Trigonocerca typica (trilobite) Zone of the Utah and the overlying Reutterodus andinus (conodont) Zone. This abrupt early Blackhillsian lithofacies change features the appearance of chitinozoans and conodonts known from marginal successions, and records the Laignet Point highstand (new). This highstand is recognized across Laurentia on the west Newfoundland and southern Midcontinent platforms. It is recorded on the east Laurentian continental slope by lower Oepikodus evae Zone dysoxic black mudstone in the Taconian allochthons. Taxonomic re-evaluations include Ulrichodina Branson and Mehl, 1933, with its genotype species U. abnormalis (Branson and Mehl, 1933) emend., as the senior synonym of Colaptoconus Kennedy, 1994; Eucharodus Kennedy, 1980; and Glyptoconus Kennedy, 1980. Paraserratognathus An in An et al., 1983, emend. is the senior synonym of Wandelia Smith, 1991 and Stultodontus Ji and Barnes, 1994. Tropodus Kennedy, 1980 is the senior synonym of Chionoconus Smith, 1991. The trilobite fauna of the Sciota Member includes species of Isoteloides, Benthamaspis, Acidiphorus and Carolinites, of which I. fisheri is new.

Two isolated cephalopod jaws recovered from the middle Turonian of the Obira area and the Campanian of the Nakagawa area, Hokkaido, Japan, consist of short outer, and large and posteriorly elongated inner “chitinous” lamellae, with a sharply pointed rostrum in the outer lamella. These features are common with the upper jaws of Recent cephalopods. Comparison with the upper jaws of ammonoids and Recent cephalopods indicates that the two Cretaceous upper jaws are attributed to the Coleoidea other than the Octopodida. This assignment is also suggested by the cladistic analysis of the Nakagawa specimen compared with five upper jaw characters on 22 Recent cephalopod species. The Obira specimen differs from the Nakagawa specimen in having a much smaller jaw and a larger jaw angle, but its order-level assignment could not be determined because of imperfect preservation. The Nakagawa specimen shares several common features with the upper jaws of Recent Oegopsina; thus we assigned its higher systematic position to this suborder. Based on the extremely large upper jaw (97 mm maximum length), a new genus and species (Yezoteuthis giganteus) is proposed. This new taxon would have been as large as the modern giant squid Architeuthis, which commonly exceeds more than 5 m in body length. Our study postulates that studies of jaws are important to reconstruct the phylogeny of the Coleoidea.

Exuviae comprising immature growth stages allow the tracing of morphological and morphogenetical features of the reduced-eyed phacopid species Plagiolaria poothaii Kobayashi and Hamada, 1968, from the Early Devonian of Satun Province, southern Thailand. Biometric and morphometric approaches have been used to characterize the shape changes. This is the fourth phacopid genus for which ontogenetic information is known. Ontogenetic features of this species are generally similar to those of Phacops and Weyerites. However, the ankylosis of the facial sutures occurs at the end of the meraspid period, later than in Phacops, and this is probably a derived character.