The assemblage of lagenide foraminifers in uppermost Permian rocks of the central Taurides consists of 22 species in 16 genera, including the new species Rectostipulina pentamerata, plus additional unidentified elements. Of these, only two identifiable species in “Nodosaria” and indeterminate syzraniids survived the end-Permian mass extinction. The last occurrences of most taxa fall within the upper half-meter of the Permian System, a pattern consistent with abrupt extinction when tested for the Signor-Lipps effect. Permian survivors are joined locally in the Lower Triassic and lower Middle Triassic by three additional species. Globally, lagenide species diversity remained low until latest Anisian time, and probably did not reach pre-extinction levels until Late Triassic or Early Jurassic time. The survival of the lagenide clade, in contrast to the complete elimination of fusulinoidean fusulinides, may be linked to the lagenides' comparatively greater paleoenvironmental tolerances and wider paleogeographic distribution. Evaluation of lagenide extinction and survival across the Permian–Triassic boundary in the central Taurides is complicated by a facies change from bioclastic wackestones and packstones to oolitic grainstones near the top of the Permian, and by the development of variably dolomitized and pyritic stromatolites and overlying oolites in the lowest Triassic. The stromatolitic and oolitic Lower Triassic lithologies represent a sedimentologic response to the end-Permian mass extinction and unusual Early Triassic marine environments. Stromatolites likely became established as disaster forms in an ecologically permissive period that lacked normal marine grazing and bioturbating benthos. Their calcification and preservation may have been promoted by high carbonate saturation levels. Oolites, which are found in recurring facies associations with stromatolites and other anachronistic carbonates in Lower Triassic rocks throughout the Tethyan embayment, probably also formed in response to elevated saturation levels and the absence of a skeletal sink for carbonate.

Abundant and well-preserved radiolarians are reported from a limestone sample taken from near the town of Fojnica, southern Bosnia and Herzegovina. A late late Ladinian age is assigned to this sample based on the index species Spongoserrula fluegeli and Muelleritortis cochleata and associated radiolarian fauna.

As a result of taxonomic studies on the entactinarian and nassellarian fauna of this sample, three species (Pseudostylosphaera multispinata, P. oblonga, and P. procera) from the suborder Entactinaria, and 18 species (Bulbocyrtium cordeyi, B.? longobardicum, Goestlingella goricanae, G. pseudoillyrica, Monicasterix ornata, M. parvisegmentata, M. pulchra, Nabolella brevispinosa, N. crenulata, N. trispinata, Ladinocampe dinarica, Spinotriassocampe praecarnica, Pseudosaturniforma ladinica, Pararuesticyrtium coniformis, P.? sanfilippoae, Conospongocyrtis bragini, Castrum blomei, and Triassocyrtium longum) from the suborder Nassellaria are described as new. Moreover, the genus Pseudosaturniforma is emended based on the new materials.

The parautochthonous Anisian and Ladinian rocks of the New Pass Range previously referred to as the Augusta Mountain Formation have a unique, endemic assemblage of pteriomorphian bivalves with Triassic Northern Hemisphere biogeographic relationships, especially to the Carnian cratonal faunas of northeastern British Columbia as well as to Ladinian faunas of the Shoshone Mountains and the Gillis Range. A new suborder Prospondyloidina is described, as well as three new genera, Promysidiella, Loxochlamys, and Nevadapecten, a new subgenus, Gervillaria (Baryvellia), and 17 new species either named or referred to by letters: Promysidiella planirecta, P. desatoyensis, Bositra favretensis, Enteropleura species a, Gervillaria (Baryvellia) ponderosa, Atrina sinuata, Antiquilima ladinica, Palaeolima newpassensis, Plagiostoma acutum, Leptochondria shoshonensis, Asoella? species a, b, and c, Oxytoma (Oxytoma) grantsvillensis, Pleuronectites newelli, Loxochlamys corallina, and Nevadapecten lynnae. Promysidiella aff. otiosa is a new combination for Mytilus otiosus McLearn; Mysidiella newtonae n. sp., Norian, Wallowa terrane, is based on Krumbeckiella cf. timorensis (Krumbeck) of Newton, 1987. Triassic “Posidonia” is placed in Bositra de Gregorio, 1886, regarded as a senior synonym of Peribositria Kurushin and Trushchelev, 1989. The morphological and stratigraphic sequence Bositra-Enteropleura-Daonella-Aparimella-Halobia is rooted in Paleozoic Caneyella and Posidonia and indicates declining dependence on and eventual loss of byssal attachment as well as a possible shift from low to high dispersal ability (between Bositra and Enteropleura). There is no evidence for trans-Panthalassan dispersal of bivalves in low latitudes within the interval of Ladinian coral beds. So-called Tethyan and Muschelkalk species are endemics in slowly evolving genera or are phylogenetically convergent on west Tethyan species.

The systematic position of the Ordovician calcareous microfossil Halysis Høeg, 1932 has long been uncertain. Only known from thin sections, its morphology has been suggested to be either a single chain of cells or a series of tubes and it has been regarded as a green alga or cyanobacterium. Here we propose that Halysis represents a single sheet of cells. This new morphological interpretation accounts for Halysis's appearance in thin section as an extended flexuous series of cells, some of which are not seen to be in mutual contact, exhibiting nonlinear cell-size variation. It is also consistent with the absence of tubiform sections unequivocally attributable to Halysis. This reassessment suggests comparisons between Halysis and Mesozoic–Cenozoic thin laminar unistratose coralline red algae. Halysis cells are relatively large (40–210 µm), but their lower range is comparable to cells of corallinaceans such as Lithoporella (Foslie) Foslie, 1909. Applanate thallus morphology in Halysis resembles that of thin laminar species of Lithophyllum Philippi, 1837 that were traditionally included in Titanoderma Nägeli, 1858. Interpretation of Halysis as a coralline-like alga strengthens the likelihood that a variety of corallines was present in the Ordovician, more than 300 Ma prior to the currently recognized major diversification of this important group of red algae in the Cretaceous.

Nearly continuous carbonate deposition more than 70 million years ago on the Panthalassan buildup is recorded in the Upper Paleozoic limestone blocks and breccias in the Itsukaichi–Ome area, west Tokyo. These blocks and breccias resulted from the collapse of the seamount and tectonic mixing with trench-fill deposits and are contained in the Jurassic accretionary complexes of the Chichibu Terrane. One hundred and five species of Permian foraminifers from 64 localities are distinguished in them, in addition to the previously reported 65 species of Carboniferous ones from 36 localities. These faunas are identical with or comparable to those known from 24 fusulinacean zones among 26 that are distinguished in the Japanese Upper Paleozoic. Neoschwagerinids, and some of schwagerinids and verbeekinids, are very characteristic in the Chichibu faunas of the Panthalassan Province. These Middle Permian fusulinaceans are more closely related faunistically to those of some exotic terranes in the circum-Pacific than of the coeval Akiyoshi faunas and the Kurosegawa faunas of Japan. In relation to the provincialism and endemism of fusulinaceans, and paleo-position and travel history of circum-Pacific terranes, important fusulinaceans in this area are represented by: 1) Acervoschwagerina, a specialized, large-sized, inflated schwagerinid in the Artinskian (Yakhtashian); 2) Parafusulina japonica, a schwagerinid entirely lacking in the Permian terranes of Japan in the upper Wordian (upper Murgabian); 3) many diversified Misellina in the Kungurian (Bolorian) and lower Roadian (lower Kubergandian); and 4) well-traceable Maklaya–Neoschwagerina–Yabeina evolutionary lineage in the upper Roadian to Capitanian (Midian).

Three new and one completely preserved species of hexactinellid sponges are described from Early Cambrian black shales of South Anhui, China. The sponges occur in the middle part of the Huangboling Formation, which is assigned to the early Canglangpuian based on trilobite biostratigraphy. Metaxyspongia skelidata n. gen. and sp. and Hexatractiella dongzhiensis n. sp. are subcylindrical thin-walled Protospongiidae. Ratcliffespongia multiforamina n. sp. is assigned to the Hintzespongiidae. With these new sponges, the first occurrences of the Protospongiidae and Hintzespongiidae, and of Hexatractiella Mehl, 1996, can be traced back to the Early Cambrian. Solactiniella cf. plumata Steiner et al., 1993, with irregular rossellimorph skeletal architecture and regular spicular organization, is found here associated with the above species. Thus, the Anhui assemblage can be considered as intermediate between Atdabanian shallow-water communities of hexactinellids with irregular skeletons and the Middle Cambrian deepwater sponge facies characterized by regularly organized Hexactinellida.

An early late Emsian codiacrinid and Frasnian specimens of an indeterminate species of Parapisocrinus, an undesignated new genus of a catillocrinid, and two amabilicrinids are described from the eastern part of the Anti-Atlas Mountains of Morocco. These are the first articulated crinoid specimens reported from the Famennian of Morocco. Specimens occur within ammonoid-rich dysoxic shales, marls, and thin limestones at Ouidane Chebbi, Jebel Mrakib, Lambidia, and Rich Bou Kourazia. Parapisocrinus, the codiacrinid, and the catillocrinid are loose cups that are associated with other megafossils and may have been transported within the pelagic depositional settings. The amabilicrinids occur in three small unitaxial lenses, two of which have associated logs. The problems with and possibility of a pseudoplanktic lifestyle for stemmed crinoids are discussed.

These new collections expand the known stratigraphic and geographic distribution of the pisocrinid and amabilicrinids and the early evolutionary history of the catillocrinids. New taxa introduced are the amabilicrinids Mrakibocrinus bockwinkeli, Moroccocrinus ebbighauseni, and the codiacrinid Elicrinus? weyeri.

A new lyssacinosan hexactinellid, Rossella bromleyi n. sp., is described from the Upper Cretaceous of Arnager Pynt, Bornholm (Denmark). The sponge shows a cup-shaped form with a broad, moderately dense root tuft, which contains three- and four-rayed orthotropal anchors characteristic for Rossella. The skeleton is composed of bundles of diactines, hexactines of two orders, and pentactines. Diactine bundles are mainly in the growth direction or diagonal to it. Prostalia lateralia are pentactines with the paratangential rays protruding beyond the outer surface of the sponge body. Hypodermalia are absent.

Since 1908, the peculiar North American primate Picrodus Douglass, 1908 (Picrodontidae; Plesiadapiformes) has been thought to contain only a single species, P. silberlingi Douglass, 1908, of late Paleocene age. However, new collections from the Paskapoo Formation, Alberta, Canada, reveal that instead a rich complex of Picrodus species lived during the Paleocene. Three of these, Picrodus calgariensis, P. canpacius, and P. lepidus, are described herein as new. Others, represented by more fragmentary specimens from Canada and the United States, are included in this paper, but are not named. P. calgariensis, from Who Nose? (late Torrejonian), Calgary, is the most primitive known species of Picrodus, having molars with little crenulation of the enamel. P. canpacius, from Cochrane 2 (earliest Tiffanian), northwest of Calgary, most resembles P. silberlingi sensu stricto, but differs in P4 structure, denser enamel crenulation, and weaker molar cusps. P. lepidus, from DW-2 (middle Tiffanian), near Red Deer, is the most advanced, having, for example, a two-rooted P4, tiny p3, and single-rooted p4. At least two of these species also occur in the United States, documented by fossils referred to P. silberlingi by previous workers. Dental evolution within Picrodus seems marked by several trends, including increase in size of i1, simplification of P4, reduction of molar cusps and crests, enlargement of the horizontal occlusal surfaces of the molars, and greater crenulation of enamel. From present knowledge, Zanycteris paleocenus Matthew, 1917 is dentally more primitive than Picrodus, Draconodus Tomida, 1982 is a valid genus, and picrodontids probably originated from “purgatoriid-grade” plesiadapiforms in earliest Paleocene time.

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.

We have studied the pattern of graptolite species turnover during the latest Ordovician mass extinction based on four continuous Ashgillian to earliest Llandovery sections together with data from more than 30 other published sections. The studied sections represent relatively shallow-water and deeper-water belts in the Yangtze Platform region. Using temporally scaled range data, species diversities and extinction and origination probabilities have been calculated using several analytical methods, including a capture-mark-recapture method. We test the statistical significance of these results and the apparent taxonomic selectivity of extinction and origination via Monte Carlo simulations and contingency analysis.

Graptolite species diversity within the Yangtze Platform rose steadily during the late Ashgill, until in the mid-late Paraorthograptus pacificus Chron, when rising extinction risk overtook origination. Diversity dropped to very low levels during the early Hirnantian when extinction probabilities attained significantly elevated rates for a period of 600–900 Ky. The period of high extinction risk was followed immediately by a short period of very high origination probability. A second, short period of high extinction risk occurred at the end of Hirnantian time. The Hirnantian extinction events marked a change from relatively low, steady origination and extinction probabilities to a prolonged period of elevated extinction risk and highly variable origination probability that extended well into the Rhuddanian. Extinction and origination was highly selective during the Hirnantian and favored both the survival and diversification of the Normalograptidae relative to the Dicranograptidae, Diplograptidae, and Orthograptidae.

The main phase of extinction in the latest Rawtheyan and early Hirnantian was coincident with continental glaciation in the Southern Hemisphere. The resulting changes in ocean circulation and oxygenation appear to have almost completely eliminated the preferred habitat for most graptolite species. The Yangtze Platform region, however, may have served as a refugium for many taxa that disappeared earlier in other regions as well as a host site for the initiation of graptolite rediversification. Following the end of the glaciation, conditions favorable for graptolite proliferation were restored but graptolite communities remained unstable for much of the late Hirnantian and early Rhuddanian. Accordingly, the Hirnantian mass extinction appears to have fundamentally altered graptolite species dynamics as well as clade dominance patterns. A full understanding of the history of life requires an expanded, hierarchical theory of evolution that gives to mass extinctions (and other levels of selection) an appropriate role in determining clade and diversity histories.

Well-preserved earliest Ordovician (early to middle Tremadocian) radiolarian faunas were recovered from carbonate rocks of the Cow Head Group of the Great Northern Peninsula of the island of Newfoundland, Canada. The earliest Ordovician faunal assemblages are from Green Point, Martin Point, Broom Point North and South, and St. Paul's Inlet in Gros Morne National Park. Latest Cambrian faunas were also recovered from Green Point and St. Paul's Inlet, but are extremely low in both abundance and diversity. The radiolarian faunas include five families, 10 genera, and 24 species. Of these, one family Aspiculumidae, one genus, and 19 species are new. The new family and new genus are Aspiculumidae and Aspiculum, respectively. The new species are Pararcheoentactinia? cowheadensis, Aspiculum eccentricum, Aspiculum? angulatum, Parechidnina delicata, P. variospina, Curvechidnina multiramosa, Echidnina conexa, E. laxa, E. semiconexa, E. severedeformis, Echidnina? immanis, Palaeospiculum curvum, P. multifurcatum, P. neofurcatum, P. tetractium, Protoentactinia deformis, P. kozuriana, P. primigena, and P. transformis. The Aspiculumidae is established on the basis of the new genus Aspiculum and on Parechidnina, whose family-level assignments were previously indeterminate. The new family Aspiculumidae is distinguished from the other four families by the absence of the spicule system.

All genera of the earliest Ordovician radiolarian faunas can be placed in the families Aspiculumidae, Archeoentactiniidae, Echidninidae, Palaeospiculumidae, and Protoentactiniidae, as can the genera of the Cambrian radiolarian faunas. However, echidninids from Cambrian faunas are generally characterized by interlocked or fused spicules whose original structure is recognizable, while those from the earliest Ordovician are commonly characterized by fused and/or modified spicules. Also, the very rare protoentactinids of the Late Cambrian are extremely abundant and diverse in the earliest Ordovician faunas described herein. Specimens of the families Palaeospiculumidae and Archaeoentactinidae are less diverse and/or less plentiful in the earliest Ordovician compared to those in Cambrian. The genus Parechidnina, which now belongs to Aspiculumidae, is more plentiful and very diverse in the earliest Ordovician, and, at the same time, lineages of the new genus Aspiculum and a related not-yet-named genus began to evolve.

The detailed biostratigraphic ages of the earliest Ordovician radiolarian faunas were determined mainly by the co-occurring conodonts. The age range of the earliest Ordovician faunas represented extends from the Cordylodus lindstromi Zone through the C. angulatus Zone to the Rossodus manitouensis Zone.

A faunule of silicified hypercalcified “sphinctozoan” sponges has been recovered from a clast of Upper Ordovician limestone out of the Early Devonian Karheen Formation on Prince of Wales Island in southeastern Alaska. Included in the faunule are abundant examples of the new genus Girtyocoeliana, represented by Girtyocoeliana epiporata (Rigby and Potter), and Corymbospongia adnata Rigby and Potter, along with rare Corymbospongia amplia n. sp., and Girtyocoelia(?) sp., plus common Amblysiphonella sp. 1 and rare Amblysiphonella(?) sp. 2. The assemblage is similar to that from Ordovician clasts from the eastern Klamath Mountains of northern California. This indicates that the Alexander terrane of southeastern Alaska is related paleogeographically to the lithologically and paleontologically similar terrane of the eastern Klamath Mountains.

This lithology and fossil assemblage of the clast cannot be tied to any currently known local rock units on Prince of Wales Island. Other clasts in the conglomerate appear to have been locally derived, so it is inferred that the limestone clasts were also locally derived, indicating the presence of a previously undocumented Ordovician limestone unit on northern Prince of Wales Island.

The two new sponges, Diagonodictya crusta n. gen. and sp., a small steeply obconical, dictyospongiid hexactinellid, and Pohlispongia monosphaera n. gen and sp., a spheroidal, single-chambered, monaxonid demosponge—along with several isolated hexactinellid spicules—are described from low-energy, low pH, black shales within the Pennsylvanian Desmoinesian Carbondale Formation from northwestern Illinois, from the Illinois Basin. They are associated with a variety of small fossils, which range from radial and spheroidal to lobate obconical, here identified only as forms A and B, that are possible spore-bearing organs of plants. Some of these latter forms occur as core debris associated with fine hexactine-derived sponge spicules and bivalve? fragments in fecal pellets. The described assemblage may have lived as pelagic organisms in a protected environment and may have been deposited under swamp “flotants” in anoxic shallow water conditions. Alternatively, the assemblage may have lived as part of an open water pelagic biota, ending up in death in anoxic, deeper water environments.

Echinoids are among the most conspicuous and diverse constituents of the Upper Cretaceous and Paleocene marine invertebrate fauna of Argentina. Nine species were collected from localities exposing the Jagüel (Maastrichtian), Roca (Maastrichtian–Danian), Salamanca (Danian), Arroyo Barbudo (Danian), El Fuerte (Danian), and Arroyo Salado (Danian) Formations in northern Patagonia, Argentina. Only one of these taxa, Paraster joannisboehmi (Oppenheim in Böhm, 1903), has been described previously from Argentina. Four taxa, Gauthieria menuthiae (Lambert and Savin in Lambert and Thiéry, 1911), Nucleopygus pullatus (Stoliczka, 1873), Diplodetus nutrix (Lambert in Boule, 1899), and Hemiaster hawkinsi Lambert, 1933, have been described previously from Madagascar. One species, Micropsis desori (Cotteau in Leymerie and Cotteau, 1856), has been described previously from France. One taxon, Pygopistes parrasae is a new species. Argentinian cassiduloids include the only two known Danian species of Nucleopygus and Pygopistes. The spatangoids were not strongly affected by the K-T extinction event. Comparisons of the Patagonian echinoids with those of the Northern Hemisphere indicate that they were strongly influenced by dispersal from Tethyan sources.

A thin unit of limestone at the base of the Val d'Homs Formation, close to the Middle–Upper Cambrian boundary, at the Ferrals-les-Montagnes section in the Montagne Noire (southern France), has yielded a fauna including linguliformean brachiopods. Although it is dated as early Late Cambrian by the trilobite association, the recorded brachiopods would suggest a latest Middle Cambrian age. Nine taxa of linguliformean brachiopods are described, including the new genus and species Ferralstreta globosa, and the new species Angulotreta brevis, Dactylotreta bacula, and Schizambon convexus. It is the first record of phosphatic-shelled brachiopods obtained by acid etching in southwestern Europe. All the genera show a great latitudinal dispersion but at species level the association is highly endemic.