Brachiopods assigned to eight genera and 15 species have been recovered from Upper Cambrian (Franconian and Trempealeauan Stages) and lowest Ordovician strata in the Arbuckle and Wichita Mountains of Oklahoma. Species of Ocnerorthis and Eoorthis occur in the Reagan Sandstone and Honey Creek Limestone of the Timbered Hills Group. Species of Billingsella appear in the Honey Creek and range upward into the overlying Fort Sill and Signal Mountain Limestones of the Arbuckle Group. Species of Cymbithyris, Finkelnburgia, Nanorthis, and Apheoorthis succeed each other upsection in the Signal Mountain Limestone. Five brachiopod zones and one subzone have been established that can be used to correlate the measured sections in the Arbuckle and Wichita Mountains, and to correlate with varying degrees of confidence from Oklahoma to similar brachiopod occurrences in other areas in the United States.

Lercaritubus problematicus Flügel, Senowbari-Daryan, and Di Stefano, 1990, a problematic organism, was initially described from Lower and Middle Permian rocks of Sicily, was subsequently recognized in Upper Permian reefs of Oman and reefal limestones of the Tethyan realm. It is here described for the first time from North America, from the Middle Permian reefoidal Upper Capitan Limestone of the Guadalupe Mountains in New Mexico. Lercaritubus problematicus has a stratigraphic range of Lower to Upper Permian and occurs widely in Permian tropical reef deposits.

A distinctive spiral unilaminate cyclostome bryozoan, recently discovered in the Eocene Castle Hayne Limestone Formation of eastern North Carolina, is described as Crisidmonea archimediformis new species. Colonies have a thickened spiral axis bearing systems of bifurcating branches. When worn and stripped of their branches, the resistant axes closely resemble the familiar screws of the Carboniferous to Permian fenestrate bryozoan genus Archimedes. However, the Eocene screws are shorter and become more loosely coiled with growth, corresponding to a helicospiral rather than a helical form. The paleoenvironment inhabited by C. archimediformis colonies is inferred to have been on the shallow (< 30 m depth) margin of an open marine, waveswept embayment. Autozooid distribution and the gradient of increasing apertural size from branch reverse to frontal sides in C. archimediformis resemble those of the living cyclostome Exidmonea atlantica and suggest colonial water currents that flowed upwards and inwards through the spiral colony. Polyascosoecia, a genus closely related to Crisidmonea, is shown to be an objective junior synonym of Reteporidea, and the new genus Polyascoeciella (type species Idmonea foraminosa Reuss) is introduced for species with exterior-walled gonozooids that were previously assigned to Polyascosoecia.

The late Llandovery through late Ludlow sequences of the stable carbonate platform of Gotland (Baltic Basin; western side of the Silurian paleocontinent Baltica) and the carbonate ramp of the Welsh Borderland area in England contain a richly fossiliferous fauna of atrypid brachiopods, including more than 60 species. This was a time of diversification for the atrypids in the tropical equatorial latitudes, with new lineages appearing for the first time that were to dominate the Devonian Period. Included in this burst of new groups was the ribbed atrypid group, the Plectatrypinae (new subfamily), which quickly led to the first spinose atrypids, the Spinatrypinae. For the Plectatrypinae, a new subgenus and species, Plectatrypa (Gutnia) capidula, and a new genus, Xanthea, are described. The evolution of expanded growth lamellae and frills on the shell at this time led not only to the growth of large shells assignable to Atrypa, but also to the rise of affiliated ribbed taxa, such as the perireefal and reefal genus Endrea echoica new genus and species (Wenlock-Ludlow). The nature, affinities and taxonomy of the smooth atrypid Lissatrypa obovata (Sowerby) from the U.K. are also clarified, indicating that the type species for the unrelated genus Glassia needs to be revised.

Late Permian reefal blocks exposed in the Ba'id area of the Eastern Oman Mountains yield a sphinctozoan assemblage that has not been studied previously. The sphinctozoan fauna described here is the first report of such an assemblage from the Arabian Peninsula. Approximately 70 samples were studied with respect to systematic paleontology, as well as frequency of taxa based on presence/absence lists. The sphinctozoans include 14 genera and 25 species. One genus (Rahbahthalamia) and five species (Amblysiphonella omanica, Salzburgia? irregularis, Welteria? hawasinensis, Thaumastocoelia? irregularis, and Girtyocoelia gracilis) are described as new. Amblysiphonella Steinmann (1882), Colospongia Laube (1865), and Sollasia Steinmann (1882) have the highest species diversity. On a generic level, Sollasia, Amblysiphonella, and Parauvanella Senowbari-Daryan and Di Stefano (1988) occur most frequently in the investigated samples. The described fauna exhibits close relationships to sphinctozoan faunas known from the Middle and Late Permian of China and Tunisia.

The fixosessile, perireefal to reefal Devonian epibiont Davidsonia cemented itself by its entire ventral valve to the underside of alveolitid tabulate corals, or to stromatoporoid sponges. It occupied a cryptic niche in perireefal biostromal thickets to reef complexes in the Old World faunal realm (Europe, western North America), and Uralian–Central Asian faunal province. A new species, D. septata, is here reported in abundance for the first time from Middle Devonian (Givetian) rocks of Yunnan, thus extending its range to South China. The usual absence of the brachial valve is suggested to be due to postmortem taphonomy as a result of its unique, cemented mode of life on the undersides of corals or sponges. A new genus of coarsely ribbed, partly libero-, partly fixosessile davidsoniid, Rugodavidsonia, type Davidsonia woodwardiana (DeKoninck), mimicking unrelated Late Paleozoic orthotetids, is also described, demonstrating that ribs evolved secondarily in a family dominated from its inception by smooth shells. Its paleogeographic distribution ranged from Europe through western North America (and possibly China), commonly accompanying Davidsonia in similar assemblages, but with a slightly different mode of life. Reexamination of available material, using thin sections, peels and SEM, confirms that the impunctate shell structure, dorsally directed spiralia, nature of the hinge mechanism, the deltidial plates, absence of a chilidium, “atrypoid” musculature and vascular markings, show features in Davidsonia and Rugodavidsonia that are all typical of the Order Atrypida. Thus, Davidsonia demonstrates that ventral valve cementation evolved independently more than once in articulate brachiopods such as strophomenids, productids, atrypids, and thecideid spiriferids. A revised classification of the Davidsonioidea and Palaferelloidea is proposed. Relationships between various genera are outlined in a new family tree for these groups. The various families discussed, including the Symmatrypidae, are united under a new suborder, the Davidsoniidina, a primarily carbonate platform and perireefal dwelling group, which first evolved during the Ludlovian (Late Silurian) in the Uralian–Central Asian tropical shelf region, diversified over a period of ~47 Ma, and then died out during the late Givetian, 10 Ma prior to the Frasnian–Famenian mass extinction events.

Observed diversity of bryozoans within Devonian stages is not significantly different from range-through values for species because very few species have ranges longer than a single stage. Generic diversity differs significantly between observed stadial and stadial range-through values except for the diverse Givetian faunas. Among families, observed stadial and range-through comparisons differ significantly in the lower diversity Early and Late Devonian but are not significant in the taxonomically diverse Middle Devonian. The patterns of Devonian generic and familial diversity are apparently robust proxies for specific diversity.

Givetian specific and generic extinctions, based on generated bootstrap distributions, are significantly higher than the other six Devonian stages even when modifications for different stage durations are considered. Based on present data, we conclude that a major change in Devonian diversity occurred between the Givetian and the Frasnian stages. Givetian specific and generic extinctions are not “smeared” with respect to adjacent stages and should qualify as a mass extinction among bryozoans pending more accurate data on bryozoan ranges and more precision in radiometric dating of Devonian stadial boundaries. Devonian bryozoan familial extinctions are not numerous and do not exhibit a significant number of extinctions for any stage. The Givetian extinction, which for the time being ranks as the largest bryozoan extinction in the Phanerozoic, is a global event with a marked local effect in the Hamilton-Tully fauna of New York, Pennsylvania, and Ontario.

Givetian specific originations are significantly higher than bootstrap distributions for both raw data and data modified for stadial durations. A Givetian generic high in originations for raw data is not significant when modified for stadial durations and only Eifelian familial originations are significantly higher than bootstrapped distributions.

Rare patellogastropod limpets are described from the Cenomanian to Campanian (Cretaceous) age sediments in Hokkaido, northern Japan and Sakhalin, eastern Russia. Shell structure analysis has revealed the presence of five shell structure groups within six species, permitting the allocation of three of the species identified to modern clades. However, the other three species recorded belong to shell-structure groups not known at the present day. The species described in this paper are Patella soyaensis new species, Patella sp., Patelloida obirensis new species, ?Patelloida miyauchii new species, an indeterminate species of the Lottiinae, and an indeterminate species and belonging to an unknown family. Two species are recognized as belonging to the Patellidae and three species to the Lottiidae, demonstrating that two of the three major families found to inhabit present-day rocky shore environments already existed in the Cretaceous. The discovery of two Patella species belonging to a modern clade found in South Africa indicates that the fossil record of the clade dates back more than 80 Ma and the distribution of the clade has changed markedly since that time. The occurrence of Patelloida from the northwestern Pacific further elucidates the worldwide distribution for this genus during the Cretaceous.

Twenty-four species of pteropods are described from the Pliocene Miyazaki Group in the Tsuma-Takanabe district, Miyazaki Prefecture, southwest Japan. Five are new: Clio shibatai new species, Cuvierina miyazakiensis new species, Cavolinia floridana japonica new subspecies, C. itoigawai new species, and C. vendryesiana hyugaensis new subspecies.

The pteropod fauna of the two lower members of the Miyazaki Group consists largely of extinct species. Whereas more than one-half of the species of the two upper members are extant.

Twelve species, Limacina sp., Clio hataii (Noda, 1972), C. shibatai new species, Cuvierina miyazakiensis new species, Bowdenatheca? sp., Diacria digitata subsp. indet., Cavolinia floridana japonica new subspecies, C. cf. C. gypsorum (Bellardi, 1873), C. itoigawai new species, C. mexicana (Collins, 1934), C. rattonei Simonelli, 1896, and C. vendryesiana hyugaensis new subspecies seem to serve as good index fossils for the Pliocene.

North American Pacific Slope deposits of Coniacian to Maastrichtian age have yielded eight biostratigraphically useful species of Anchura: A. (Helicaulax?) popenoei new species, Coniacian; A. halberdopsis new species, early Campanian; A. callosa Whiteaves, 1903, early Campanian; A. falciformis (Gabb, 1864), late early to middle Campanian; A. phaba new species, middle to late Campanian; A. ainikta new species, middle to late Campanian; A. gibbera Webster, 1983, late Campanian to early Maastrichtian; A. baptos new species, late Maastrichtian to early Danian. In addition, two other possible species are A. nanaimoensis (Whiteaves, 1879), middle to late Campanian, and Anchura? new species, late Maastrichtian. These species together with two additional Turonian species, A. (Helicaulax) tricosa Saul and Popenoe, 1993, and A. (H.) condoniana Anderson, 1902, allow the definition at least eight Late Cretaceous Anchura zones for the Pacific Slope. These zones have durations of 1.5 m.y. to 4 m.y.

Anchura (H.?) popenoei from northern California appears most closely related to A. (Helicaulax) tricosa Saul and Popenoe, 1993, of Turonian age from southern California. Anchura callosa, A. falciformis, A. nanaimoensis, and A. phaba appear to be closely related based on sculptural elements, as does A. gibbera despite having an anterior spur on the wing. However, these species appear to belong to two latitudinally differentiated faunal provinces. Species having a northern range include A. callosa, A. falciformis, and A. nanaimoensis, whereas A. phaba and A. gibbera are from more southern deposits, as are also A. halberdopsis, A. ainikta, and A. baptos.

The record of the fossil representatives of the family Juliidae is updated. The new genus Candinia is proposed, in the subfamily Juliinae, for two fossil species somewhat intermediate between Julia and Berthelinia. The new species Candinia pliocaenica is recorded from the lower Pliocene shallow marine deposits near Siena (Tuscany, Italy). This is the first record of Sacoglossa in the Mediterranean Basin. Based on the very specialized life habits of the Juliidae, it is suggested that subtropical Caulerpa algal prairies inhabited the Mediterranean during the early Pliocene, likely becoming extinct in this basin because of the mid-Pliocene climatic deterioration.

Following the mass extinction event at the end of the Cretaceous, the marine molluscan faunas of the high southern latitudes underwent a marked period of diversification during the early Paleocene. The appearance of four new species belonging to the new genus Seymourosphaera, tentatively placed in the subfamily Pseudolivinae, from the lower Paleocene strata of Seymour Island, Antarctic Peninsula, clearly illustrates the post-Cretaceous extinction diversification. The abrupt radiation of the buccinids during the early Paleocene, was also apparently related to geographic isolation of Antarctica during final breakup of Gondwana. Comparative analysis of shell morphology of Seymourosphaera, new genus reveals close morphologic similarities, not only with taxa within Pseudolivinae, but also with several genera and subgenera belonging to the families Buccinidae and Nassariidae. However, incompleteness of the fossil record and a “generalized” shell morphology make difficult establishment of unequivocal phylogenetic relationships for Seymourosphaera. A taxonomic review of most closely related, and possibly ancestral genus Austrosphaera Camacho, 1949, is provided. The following new species of genus Seymourosphaera new genus are described: Seymourosphaera bulloides new species, S. subglobosa new species, S. depressa new species, and S. elevata new species.

Endophyllum is described for the first time from North America. The occurrence of a single, large colony in Middle Devonian strata in New York is both biogeographically and environmentally anomalous: it belongs to an Old World Realm genus but was found in the Eastern Americas Realm, and it occurred in a gray, ambocoeliid-bearing mudstone, a facies in which morphologically complex corals are otherwise unknown. Available evidence suggests that the coral lived not far from where it was found, possibly on a hardground or bank a few km north of the outcrop. Endophyllum ciurcai new species is described.

Hispanosinuites peeli new genus and species from the Lower Oretan shales (Middle Ordovician) of central Spain is described and placed in the new subfamily Hispanosinuitinae of the family Sinuitidae. This new subfamily is considered to represent a highly specialized phylogenetic lineage, which probably separated from the morphological range of the genus Sinuites during the Early Ordovician. The outer shell surface of Hispanosinuites peeli is entirely covered by secondary shell layers, which are interpreted as perinductura, inductura and coinductura. The similarity of these shell deposits in Hispanosinuites peeli and species of Euphemites suggests that these layers were secreted by mantle flaps having the same form in both genera. Hispanosinuites peeli is interpreted as a mobile mollusc with an internal shell adapted to an infaunal mode of life. Discovery of this unusual mollusc reopens the question of the phylogenetic relations of the families Sinuitidae and Euphemitidae, which are often assigned to different molluscan classes.

Additional Whiterockian gastropods are described from the Antelope Valley Formation of Nevada. A new genus with affinities to Oriostoma is described as well as the new species Clathrospira glindmeyeri, Trochonemella antelopensis, and Raphispira martinensis. The lower ranges of Clathrospira Ulrich in Ulrich and Scofield and Trochonemella Okulitch, the species Liospira americana Billings and Raphistomina lapicida (Salter) are extended to the Whiterockian. The ranges of Raphispira Perner and the family Oriostomatidae Wenz are tentatively extended downward to the Whiterockian.

The fossil record of the volutid gastropod Arctomelon is represented by three species from the Koryak Upland and the Kamchatka Peninsula (Russian northeast), ranging in age from late middle Eocene to early Miocene. Although Recent Arctomelon stearnsii (Dall, 1872) from the northeastern Pacific is a cold-water species, paleontological data point to the origin of the genus in shallow, warm-water conditions that existed in high latitudes of the northwestern Pacific during Paleogene time. The fossil record also indicates survival of the genus during the climatic coolings through the Cenozoic. It is apparent that Arctomelon successfully adapted to the new cooler and deeper-water conditions. Despite this major change of life habit, shell morphology has remained fairly unchanged since the Eocene. Two new species of the genus Arctomelon, A. harasewychi sp. nov. and A. rateginense sp. nov., are described.

Two previously undescribed species of Bivalvia of Eocene age are herein tentatively considered to belong to the family Lucinidae because of their ligament areas and elongated anterior adductor scars. Both species are elongate for a lucinid, have edentulous hinges, striated muscle scars, and are placed in the new genus Cryptolucina. Both are found in the Humptulips Formation of middle to late Eocene age in western Washington, and both Cryptolucina megadyseides new species and C. elassodyseides new species are associated with deep-water, cold-seep limestone. Cryptolucina megadyseides is also associated with turbiditic mudstone.

The discovery of a specimen of Nautilus praepompilius Shimansky, 1957, from the Chegan Formation of Kazakhstan confirms that this species is assignable to Nautilus, and that this extant genus extends back to the late Eocene. It is morphologically closest to Nautilus pompilius Linnaeus. The nepionic constriction shows that the hatching size was ca. 23 mm dia, close to that for Nautilus pompilius (ca. 26 mm dia).