The family Actinocrinitidae was a significant contributor to the global biodiversity peak of crinoids that occurred during the Mississippian and is referred to as the “Age of Crinoids.” Although the actinocrinitids are a major component of that high diversity, they are also a source of much taxonomic confusion. Previously, generic concepts were not applied equally between Europe and North America creating disparity in the definition of genera. In this contribution, all genera are defined objectively by discrete characters, and the generic assignments of all species are reevaluated. Twenty genera are described. A total of 206 species were evaluated of which 56 species and one taxon in open nomenclature are reassigned to different genera, 21 species are designated as nomina dubia, and three species and one genus are now incertae sedis.

A phylogenetic hypothesis is presented for the relationships of the genera of Actinocrinitidae genera based on a parsimony-based analysis and plotted against stratigraphic ranges. Although groupings were revealed in this analysis, the Actinocrinitidae cannot be readily subdivided into subfamilies. Rapid diversification occurred during the Tournaisian following the Hangenberg Extinction of probable fish predators. The late Devonian (Famennian) occurrence of the highly derived genera Abactinocrinus and Physetocrinus suggests there is a more extensive, but undocumented, evolutionary history for the Actinocrinitidae during the Devonian.

A study of the Upper Ordovician trepostomate bryozoans belonging to the families Amplexoporidae and Monticuliporidae, from the eastern Anti-Atlas of Morocco, is presented here. They occur in the marly to fine-grained limestone, intermediate unit of the Khabt-el-Hajar Formation, late Katian in age, representing outer-ramp depositional environments. They inhabited the highest paleolatitude known for a bryozoan fauna during the Ordovician, estimated at more than 65–70ºS. A total of 11 species of the genera Anaphragma, Atactoporella, Homotrypa, Monotrypa, Monticulipora, and Prasopora are described. Three species are already known from the equatorial-tropical paleocontinents of Baltica, Laurentia, and Siberia: Anaphragma mirabile, Monotrypa jewensis, and Prasopora falesi. Four new taxa are described:Anaphragma undulata, Atactoporella moroccoensis, Monticulipora globulata, and Monticulipora irregularis.

The two species of Anaphragma and the one of Atactoporella display significantly larger zoarial sizes than congeneric species, representing gigantism among bryozoans. Polar gigantism is rejected for the two species of Anaphragma as is gigantism related to photosynthetic endosymbionts. An alternative proposal for their giant size is their long zoarial life span due to their well-balanced, robust branching form, with a relatively wide basal supporting surface, adapted to unconsolidated substrates in environments below wave base. Their great stability in outer-ramp environments, with infrequent storms, would allow the zoaria to grow for an extended time and reach large sizes before being overturned and buried. Atactoporella moroccoensis, has both zoaria and zooecia gigantic, suggesting a hypothesis of polar gigantism.

Yuknessia Walcott, 1919 recently was transferred from the green algae to the Phylum Hemichordata on the basis of new details observed for the type species, Y. simplex, from the Burgess Shale Formation (Cambrian Stage 5) of British Columbia. This has prompted reexamination of material attributed to Yuknessia from various Cambrian localities in South China. Findings preclude both a Yuknessia and a hemichordate affinity for all of the Chinese study material, and most of this material is formally transferred to Fuxianospira Chen and Zhou, 1997, a taxon common in the Chengjiang biota. Comparable material from the Cambrian Marjum, Wheeler, and Burgess Shale formations of North America is also assigned to Fuxianospira, and this reassignment expands both the paleogeographic and stratigraphic range of this taxon. All aspects of the study specimens, including details obtained from scanning electron microscopy, are consistent with an algal affinity, as proposed in the original descriptions of the Chinese material.

Fossil eggs of clam shrimps (Spinicaudata) are rare and little attention has been paid to the study of their shape and microstructures. Here, we report the discovery of exceptionally preserved three-dimensional eggs from numerous specimens of Eosestheria elliptica Chen, 1976 from the lacustrine Early Cretaceous Yixian Formation in western Liaoning, China. These three-dimensionally preserved fossil eggs display a spherical shape with smooth surface, part of the tertiary envelope, and possibly the first embryonic cuticle, which were previously unknown or ambiguous. The eggs are abundant and assumed to be attached to the exopod as in extant Spinicaudata. Moreover, the exceptional three-dimensional preservation and delicate preparation of slices of the eggs allowed us to document the microstructures and elemental composition of fossil eggs of clam shrimps from the Jehol Biota. Energy dispersive spectroscopy of the fossilized envelope revealed a calcium phosphate composition. However, the egg contents display two completely different elemental compositions. Some exhibit the same elemental composition as the envelope, whereas others has been replaced by alumino-silicate. The taphonomic process is also briefly discussed in this paper.

The Angosto de Lampazar, a classic locality for the study of lower Paleozoic successions in the Cordillera Oriental, NW Argentina, has yielded a late Cambrian relatively diverse, lingulate brachiopod fauna. Sandy lenses with calcareous cement from the uppermost levels of the Lampazar Formation have yielded abundant remains of articulate and phosphatic brachiopods. Among the latter, the new species Eurytreta harringtoni Mergl and Herrera, Lingulella? melonica Mergl and Herrera, Libecoviella lenticularis Mergl and Herrera, and Schizambon cardonalis Mergl and Herrera, as well as the new genus and species Saltaia lampazarensis Mergl and Herrera are formally introduced. Trilobites and conodonts from the same horizons characterize the Cordylodus proavus Zone, allowing a correlation with Stage 10 of the Furongian Series. Although the information on lingulate brachiopods from the C. proavus Zone is scarce across the world, the composition of the studied association displays a relationship with coeval and slightly younger faunas of Utah and Kazakhstan. The Argentine brachiopods, the first described from the late Cambrian Proto-Andean margin of Gondwana, are more closely related to temperate Laurentian faunas than to those from the high latitude North African margin of Gondwana.

Peritidal cherts and silicified phosphorites of the Early Cambrian Kyrshabakta (Berkuta Member) and Chulaktau formations of South Kazakhstan contain diverse assemblages of cellularly permineralized microorganisms that like other microbiotas of similar age and setting are dominated by cyanobacteria, both filamentous (oscillatoriacean trichomes and empty sheaths) and coccoidal (chroococcaceans). Although these near-shore assemblages contain sphaeromorph acritarchs, they differ from Neoproterozoic and Early Cambrian microbiotas of more open-marine environments by lacking morphologically complex planktonic eukaryotes such as the acanthomorphic acritarchs that are abundant in the Chulaktau-overlying Shabakta Formation. In general composition, the Berkuta and Chulaktau assemblages are similar both to microfossil assemblages of the pre-trilobite Rovno and Lontova Regional Stages of the East European Platform and to Early Cambrian microbiotas known from chert-phosphorite deposits worldwide.

The studies reported here are based on use of optical microscopy combined with techniques recently introduced to paleobiology: confocal laser scanning microscopy, and Raman and fluorescence spectroscopy and imagery. Taken together, these provide information in situ, in three dimensions and at high spatial resolution, about the organismal morphology; cellular anatomy; chemical composition; and mode, fidelity, and environment of preservation of the permineralized microfossils. Data are presented suggesting that the substitution of samarium for calcium in fossil-preserving apatite may provide evidence of its oxic or anoxic paleoenvironment of formation.

We interpret the Berkuta and Chulaktau assemblages to be composed of 27 taxa assigned to 17 genera of microscopic prokaryotes and eukaryotes that include one new genus and species, Berkutaphycus elongatus.

Ladinian deposits at Mt. Svilaja in Dalmatia (Outer Dinarides, Croatia) yielded an abundant brachiopod fauna of low diversity interpreted as a parautochthonous assemblage representing an ecosystem of dasycladacean submarine meadow. The fauna consists of four named species and one left in open nomenclature. The most common is the spiriferinide Flabellocyrtia flabellulum Chorowicz and Termier, 1975 (Spiriferinida) accounting for more than 70% of the material. The athyridide Cassianospira humboldtii (von Klipstein, 1845) is the only species known from elsewhere (Anisian of Southern Alps). The new species of Spiriferinida Thecocyrtella dagysii Halamski, Bitner, Kaim, Kolar-Jurkovšek, and Jurkovšek n. sp. differs from other representatives of the genus in having a deep ventral sulcus. Albasphe albertimagni Halamski, Bitner, Kaim, Kolar-Jurkovšek, and Jurkovšek n. gen. n. sp. is a new brachiopod that possesses a dorsal septum with an intra-septal cavity and dorsal submarginal ridges, both features in common with Aalenian Zellania Moore, 1855 from which it differs in lack of the ventral septum and of ventral submarginal ridges. They are interpreted as members of a sparsely recorded paedomorphic evolutionary line of terebratulides with secondarily lost loop, described formally herein as Gwyniidina Halamski and Bitner n. subordo and subdivided into newly emended Dispheniidae Grant, 1988 (Dispheniinae Grant, 1988 with the only genus Disphenia and Albasphinae Halamski and Bitner n. subfam. with Albasphe and Zellania) and Gwyniidae MacKinnon, 2006 (including Recent Gwynia and Simpliciforma). In contrast to previous interpretations, the trocholophe lophophore of Gwynia is interpreted herein as secondarily simplified.

The Lower Devonian (Lochkovian) hexactinellid sponge Talacastospongia minima new genus new species is reported from the lower beds of the Talacasto Formation in the Argentine Precordillera. It represents the first Devonian sponge from South America and the best record in the paleobiogeographic context of the Malvinokaffric Realm, otherwise virtually devoid of spiculate sponges. This discovery provides some tentative insights on the age and oldest record of the Family Pileolitidae. The paleogeographical context for this new finding shows a high latitude setting with a notable scarcity of hexactinellid sponges recorded to date in Devonian Malvinokaffric basins, and the absence of calcareous spiculate sponges (heteractinids) and hypercalcified sponges (stromatoporoids, sphinctozoans).

Several Jurassic pterioid bivalve species have been referred to Parainoceramus Cox by different authors, yet this has proved inadequate because the meaning of such genus has been compounded by nomenclatural and idiomatic problems, as well as misinterpretations. Hence, the new genus Parainoceramya is here proposed to accommodate several species previously referred to Parainoceramus, with Crenatula ventricosa J. de C. Sowerby as its type. Permian species originally assigned to Parainoceramus, including the type species, are referred to the genus Kolymia Likharev. All species attributed to Parainoceramus s.l. are reviewed and the new genus is compared with related genera. As here understood, the new genus is first recorded in the Hettangian and attained a cosmopolitan distribution; its last occurrence is probably Berriasian.

The Wenlock (middle Silurian) Eramosa Lagerstätte of the Bruce Peninsula, Ontario, Canada, is becoming known for its rich and diverse faunas, different preservational styles, and a combination of soft-body preservation associated with shelly body and trace fossils. Sampling for scolecodonts—the jaws of polychaete annelids—has yielded unique material. Hindenites parkheadensis new species is described from abundant specimens, including apparatuses, from a monospecific fauna that has allowed the complete dorsal maxillary apparatus to be reconstructed. The new species was recovered by acid digestion of carbonates, which are interpreted as having been deposited in shallow, marginally marine environments; the species may become a useful paleoenvironmental indicator, and the occurrence of Hindenites at Park Head, Ontario, is the first record of the genus outside of Baltoscandia. Bedding-plane material from Wiarton, Ontario, reveals a more diverse fauna of seven to nine additional polychaete taxa, most belonging to Kettnerites and Oenonites. Strata at Wiarton are interpreted as having been deposited in environments with good water circulation and open-marine conditions. The faunal composition of Eramosa polychaetes varied between localities of the Lagerstätte outcrop belt, supporting previous interpretations of differences in environment and/or taphonomic history. The relative abundance of scolecodonts suggests that jaw-bearing polychaetes played a significant role in the biotas that are now preserved in the Eramosa Lagerstätte. Moreover, the results underpin the notion that different polychaete species had variable environmental preferences and tolerances during the Silurian, and that polychaetaspids and paulinitids formed two of the most common and widely distributed families.

This paper reports the successive occurrence of Ptychagnostus sinicus Lu, 1957 and Ptychagnostus atavus (Tullberg, 1880) from the lower part of the Machari Formation, Yeongwol Group, Korea. Morphometric approaches of using the landmark and principal component analyses make it possible to differentiate P. sinicus from P. atavus with clarity: pygidia of P. sinicus have a relatively narrow M1, a transverse F2, and a weakly developed M2 tubercle, whereas those of P. atavus are characterized by a broadly arching M1, a chevron-shaped F2, and a prominent M2 tubercle. Recognition of P. atavus, for the first time in Korea, allows the determination of the base of the Drumian Stage in Korea and aids correlation with other parts of the world.

Four trepostome bryozoan species are described from the Upper Triassic of New Caledonia. They include one new genus Metastenodiscus n. gen. The studied fauna shows strong paleobiogeographic relations to New Zealand and less so to Japan. Morphological similarities between Middle Paleozoic and Triassic trepostome bryozoans (e.g., abundant diaphragms) are explained by homeomorphy.

A remarkable fossil assemblage composed of five gastropod taxa is described from the Early Miocene of Santa Cruz (Patagonia, Argentina) in southernmost South America. The assemblage includes extinct and living genera South America, and on geographic distributions and represent background new information on spatial and across time distributions as well as identification of new taxa. A new taxon, Patagocharopa enigmatica n. gen. n. sp., is tentatively assigned to Charopidae. Gastrocopta patagonica n. sp. (Vertiginidae) represents the oldest record of Gastrocopta in Argentina and the southernmost record for the Americas. Punctum patagonicum n. sp. (Punctidae) represents the first record of Punctum for continental South America, and characterized by a protoconch with traces of axial costulae and a teleoconch with strong radial ribs. Zilchogyra miocenica n. sp. is the first Miocene record of the charopid genus Zilchogyra. Fragments of a possible Scolodonta (Scolodontidae) are recorded. Overall, the assemblage represents an important and useful paleoenvironmental tool. This fauna suggests that a more temperate and humid environment than today—with a more dense vegetation cover—was prevalent at this site during the Early Miocene.

The geologic record of the shallow-marine gastropod genus Pseudoperissolax Clark, 1918 is documented in detail for the first time in a region of the northeast Pacific extending from southwestern Washington to northern Baja California, Mexico. This genus, which has been erroneously equated with the nomen dubium Perrisolax Gabb, 1861, comprises a very small group of species whose supra-generic ranking has been inconsistent. Pseudoperissolax is placed here in family Muricidae Rafinesque, 1815 and subfamily Muricinae Rafinesque, 1815 based on the presence of varices, a club-shaped last whorl with noded carinae, and a long siphonal canal. The genus is represented in the northeast Pacific by the late Paleocene Pseudoperissolax tricarnatus (Weaver, 1905) and the late Paleocene to late Eocene Pseudoperissolax blakei (Conrad, 1855).

Pseudoperissolax was a warm-water gastropod that most likely originated during the Late Cretaceous (Maastrichtian) in Madagascar and also questionably spread during this time to southern New Zealand. Its certain geologic range is early Paleocene to earliest Oligocene, with occurrences in western Kamchatka, southern Japan, southwestern Washington, southwestern Oregon, southern California, northern Baja California, Mexico, southern Alabama, and Nuevo León, northeastern Mexico. Whether Pseudoperissolax migrated into the northeast Pacific from Kamchatka or from Alabama and Mexico cannot be determined with certainty. The decline and eventual extinction of the genus coincided with the global-cooling event at the end of the Eocene.

Oaks and their associated gallwasps are often cited as a classic example of coevolution in a plant-insect system. Therefore, it is expected that these gallwasps should demonstrate a high degree of host fidelity over their evolutionary history. To test this, we studied 25 fossil floras from the Oligocene through Pliocene of the western United States. Galls were found on the leaves of Quercus simulata-type Knowlton, 1898 and Q. pollardiana-type (Knowlton) Axelrod, 1940, and match previously reported galls of the form genus Antronoides Waggoner and Poteet, 1996. These fossil leaf-galls are similar to those made on oaks by modern Cynipini wasps, and were restricted to two oak species. Galls are present on these oaks in western floras for a span of 30 million years, indicative of remarkable host fidelity through time. The distribution of galled leaves from across the western United States indicates that the radiation of this group of gallwasps occurred more or less simultaneously across a wide geographic area.

New Upper Ordovician trepostomate bryozoans from the eastern Anti-Atlas of Morocco have been identified. They have been collected from the lower and intermediate units of the Khabt-el-Hajar Formation, late Katian in age, representing, respectively, bryozoan-pelmatozoan meadows with siliciclastic input, degraded by wave activity in a mid-ramp setting, and outer-ramp environments with marly substrates. Ten species of the genera Cyphotrypa, Calloporella, Diplotrypa, Parvohallopora, Dekayia, and Aostipora are described. Of them, three species are new: Cyphotrypa regularis Jiménez-Sánchez, Parvohallopora cystata Jiménez-Sánchez, and Aostipora elongata Jiménez-Sánchez. Univariate statistical analyses of the sub-polar Moroccan species, in addition to other congeneric species of high, middle, and low latitudes, corroborate that for the trepostomate bryozoan the temperature of the ambient water was a primary control on zooecium size variations. Nevertheless, other environmental factors, besides temperature, must have also influenced significantly the zooid size, at least in low latitudes. Our data also give further support for considering the zooecium wall thickness as a limiting factor for the zooid size increment with latitude in the trepostomates.

The early Cambrian (Terreneuvian, Stage 2) tommotiid Kulparina rostrata Conway Morris and Bengtson in Bengtson et al., 1990 is revised. The pyramidal sclerites of K. rostrata are shown to be bilaterally symmetrical and homologues of the symmetrical S1 sclerites of Paterimitra pyramidalis Laurie, 1986. The scleritome of K. rostrata is also shown to include flattened asymmetrical sclerites that were originally described under the name Eccentrotheca guano Bengtson in Bengtson et al., 1990 and which correspond to the L-sclerites of Paterimitra. A modified tubular scleritome and a sessile filter-feeding mode of life is envisaged for Kulparina rostrata.

Light microscope and scanning electron microscope observations on new material of unicellular microfossils Dictyosphaera macroreticulata and Shuiyousphaeridium macroreticulatum, from the Mesoproterozoic Ruyang Group in China, provide insights into the microorganisms’ biological affinity, life cycle and cellular complexity. Gigantosphaeridium fibratum n. gen. et sp., is described and is one of the largest Mesoproterozoic microfossils recorded. Phenotypic characters of vesicle ornamentation and excystment structures, properties of resistance and cell wall structure in Dictyosphaera and Shuiyousphaeridium are all diagnostic of microalgal cysts. The wide size ranges of the various morphotypes indicate growth phases compatible with the development of reproductive cysts. Conspecific biologically, each morphotype represents an asexual (resting cyst) or sexual (zygotic cyst) stage in the life cycle, respectively. We reconstruct this hypothetical life cycle and infer that the organism demonstrates a reproductive strategy of alternation of heteromorphic generations. Similarly in Gigantosphaeridium, a metabolically expensive vesicle with processes suggests its protective role as a zygotic cyst. In combination with all these characters and from the resemblance to extant green algae, we propose the placement of these ancient microorganisms in the stem group of Chloroplastida (Viridiplantae). A cell wall composed of primary and secondary layers in Dictyosphaera and Shuiyouisphaeridium required a high cellular complexity for their synthesis and the presence of an endomembrane system and the Golgi apparatus. The plastid was also present, accepting the organism was photosynthetic. The biota reveals a high degree of morphological and cell structural complexity, and provides an insight into ongoing eukaryotic evolution and the development of complex life cycles with sexual reproduction by 1200 Ma.

Today, the marine gastropod genus Cittarium is present only in the West Indies faunas, represented by a single species C. pica, also known from the Pleistocene of Bermuda. Herein Cittarium praepica n. sp. is described from the Upper Miocene Cercado Formation of the Dominican Republic. This is the oldest fossil record for the genus in the eastern Tropical America. The new species is compared to the Pleistocene to Recent Caribbean C. pica and to C. maestratii Lozouet, 2002 of the Upper Oligocene of France. The importance of this new record for the geological history and the biogeography of the genus are discussed.

A new Burgess Shale-type Lagerstätte is described from the middle Cambrian (Series 3, Drumian) Rockslide Formation of the Mackenzie Mountains, Northwest Territories, Canada. The Rockslide Formation is a unit of deeper water ramp to slope, mixed carbonate, and siliciclastic facies deposited on the northwestern margin of Laurentia. At the fossil-bearing locality, the unit onlaps a fault scarp cutting lower Cambrian sandstones. There it consists of a succession of shale and thick-laminated to thin-bedded lime mudstone, calcareous sandstone, and greenish-colored calcareous mudstone, overlain by shallower water dolostones of the Avalanche Formation, which is indicative of an overall progradational sequence. The Rockslide Formation is of similar age to the Wheeler and Marjum formations of Utah, belonging to the Bolaspidella Biozone. Only two 1 m thick units of greenish mudstone exhibit soft-bodied preservation, with most specimens coming from the lower interval. However, the biota is common but not as diverse as that of other Lagerstätten such as the Burgess Shale in its type area. The shelly fauna is dominated by the hyolith Haplophrentis carinatus Matthew, 1899 along with sparse linguliformean brachiopods, agnostoid arthropods, and ptychoparioid trilobites. The nonmineralized biota includes the macrophytic alga Margaretia dorus Walcott, 1911, priapulid worms, and the carapaces of a number of arthropods. The arthropods belong to Isoxys mackenziensis n. sp., Tuzoia cf. T. guntheri Robison and Richards, 1981; Branchiocaris? sp., Perspicaris? dilatus Robison and Richards, 1981; and bradoriids, along with fragments of arthropods of indeterminate affinities. The style of preservation indicates that most soft parts underwent complete biodegradation, leaving just the more resistant materials such as chitinous arthropod cuticles. The range of preservation and similarity to the coeval biotas preserved in Utah suggests that the composition of this Lagerstätte is probably representative of the community living on the relatively deep-water ramp or slope during middle Cambrian time in Laurentia. This would argue that the extraordinary diversity of the Burgess Shale at Mount Field is anomalous.