Holorhynchus giganteus Kiaer, 1902, a common Late Ordovician (mid-Ashgill) pentameride brachiopod in the Baltic region, Kazakhstan, and southern Tien Shan, is documented for the first time from the Badanjilin Formation (mid-Ashgill) of western Inner Mongolia (Alxa block), North China. Serial sections of the Chinese material confirm the presence of a vestigial ventral median septum in the early growth stage of H. giganteus, but the septum becomes embedded in the secondary shell thickening at the adult growth stage. A survey of the type material from Norway and additional material from other regions indicates that the incipient ventral median septum is a much more commonly developed structure than was previously believed. The presence of a well-developed pseudodeltidium in the Tien Shan material of H. giganteus and the absence of such a structure in conspecific material from many other regions require a systematic revision of the generic group. Holorhynchus has rodlike crura (=brachial processes) that do not form flanges at their junctions with the inner hinge plates (=outer plates = crural plates) and outer hinge plates (inner plates). This, together with the development of a crude spondylial comb structure, points to its affinity to the Virgianidae rather than to the Stricklandiidae. Holorhynchus can be regarded as a Lazarus taxon because of its absence during the crisis (Hirnantian) and survival (early-middle Rhuddanian) intervals associated with the Late Ordovician mass extinction and its reappearance in Kazakhstan and North China during the Early Silurian (late Rhuddanian-early Aeronian). The mid-Ashgill Holorhynchus fauna, typified by a number of large-shelled pentamerides, was common in the Baltic region, the Urals, Kazakhstan, Tien Shan, Alxa, Qaidam, Kolyma, and east-central Alaska, but largely absent from Laurentia and Siberia (except for Taimyr) in the ancient tropical-subtropical regions. This paleobiogeographic pattern agrees with the general pattern of the Late Ordovician brachiopod provincialism.

Molecular clock estimates of divergence times for artiodactyls and whales vary widely in their agreement with the fossil record. Recent estimates indicate that the divergence of whales from artiodactyls occurred 60 Ma, a date which compares well with the first appearances of fossil whales around 53.5 Ma, and artiodactyls at 55 Ma. Other estimates imply significant gaps in the fossil record. A date of 65 Ma for the divergence of Suidae and Ruminantia predates the appearance of Ruminantia by over 10 million years, and an estimate of 58 Ma for the divergence of Suidae from Cetacea implies a gap of over 20 million years. Further, although a molecular clock estimate has not been reported, the hypothesis that hippos are the closest living relatives of the whales implies a potential ghost lineage for hippos of over 40 million years. There are only two living species of hippos, and their fossil record is sparse, while cetaceans and other artiodactyls are speciose and have rich fossil records. A 40-million-year gap in the fossil record of hippos could be explained by several possibilities: inadequate biogeographic sampling, taphonomic biases, or undifferentiated primitive morphology. Similarly, a number of possible problems may exist in the molecular data: rate variation in the genes sampled, the low numbers of genes examined, and insufficient age calibrations. In addition, there are potential problems in molecular phylogeny estimation, such as long branch attraction and inappropriate taxonomic sampling. Additional estimates of divergence times among living taxa should provide a broader framework for comparison with the fossil record and provide information to help identify which of these factors are causing conflict.

A previously unknown Namurian goniatite and brachiopod fauna is described from Southeast Asia. The goniatites provide new insights into their global distribution and the age of the fauna. Two new brachiopod genera, Eileenella Racheboeuf and Plicambocoelia Boucot and Brunton, and five new species are described. The brachiopod fauna is unlike any known previously from Asia.

A new coral, Blastozopsammia guerreroterion, from the mid-Cretaceous (upper Albian–lower Cenomanian) Mal Paso Formation of southwestern Mexico is the earliest known and the first Mesozoic colonial member of the Dendrophylliidae, an extant worldwide group. Blastozopsammia is characterized by a ramose corallum produced by extratentacular budding, dimorphic corallites, and branches with a continuous axial corallite sheathed in an orderly arrangement of radially arrayed secondary corallites and a robust layer of reticulate coenosteum. This growth form is similar to that of many modern reef-building species of Acropora Oken, 1815 and species of the nonreefal Petrophyllia Conrad, 1855 (=Archohelia Vaughan, 1919). Based on corallite configuration, growth form and analogy with Acropora, Blastozopsammia had a relatively high degree of colony integration and may have been zooxanthellate. The combination of an axial corallite with radially arrayed secondary corallites has been regarded as one of the morphological and ecological pinnacles of coral evolution, yet it is rare among the Scleractinia. This growth form has not been recognized in any Cenozoic dendrophylliids. Blastozopsammia is an evolutionary enigma because no ancestral lineage or closely related taxon has been identified. However, the most likely origin of colonial Dendrophylliidae is Jurassic or Early Cretaceous Actinacididae.

Abundant silicified shell plates (valves) of some of the oldest-known chitons were recovered from the Late Cambrian Notch Peak Formation of Utah. The chiton fauna is dominated numerically by Matthevia wahwahensis new species, but also includes another mattheviid, Eukteanochiton milleri new genus and species, and a preacanthochitonid, Orthriochiton utahensis new genus and species. Robustum from the Early Ordovician Gasconade Formation of Missouri is herein reinterpreted as a septemchitonid chiton, and Hemithecella, from the Late Cambrian-Early Ordovician of the eastern United States, is once again considered a mattheviid chiton. Mattheviid valves are unique among chitons in that they are massive, elongate, and contain one or two tunnels; these characteristics have led some to exclude this family from the Polyplacophora. However, mattheviids and other chitons share many valve characters, including granules, an apical shelf, a thin anterior margin, bilateral symmetry, three valve types, and a shell layer perforated with canals. Furthermore, recently described chiton valves from the Silurian of Gotland, the Ordovician of Wisconsin, and the Cambrian-Ordovician of Missouri are gradational between the Notch Peak mattheviid valves and those of younger polyplacophorans. Also, Matthevia wahwahensis n. sp. has valves with a flat apical area, allowing for valve overlap, and so provides a link between the unusual chiton Matthevia variabilis, which had nonoverlapping, spiky valves, and Chelodes, a less disputed chiton. Known fossil assemblages reveal that, along the coastline of Laurentia during the Cambrian-Ordovician, chitons were diverse, consisting of at least four families and with much variation in valve shape.

Based on well-preserved material from the Sinemurian of the western Carpathians, the new subgenus Terquemia (Dentiterquemia) is proposed, which is presently represented only by its type species T. (Dentiterquemia) eudesdeslongchampsi n. sp. Dentiterquemia is separated from Terquemia sensu stricto by a series of denticles along the hinge margin and corresponding, chevronlike ridges on the ligament area. The combination of hinge teeth with a cementing habit is interpreted as a defense strategy inhibiting torsion of the valves as well as manipulation of the animal as a whole. Whereas different kinds of articulating hinge structures evolved independently in several clades of early Mesozoic cementing bivalves, Paleozoic cementing bivalves generally lack such structures. It is proposed that this difference reflects an early Mesozoic proliferation of durophagous predators and therefore points to a beginning of the “Mesozoic marine revolution” soon after the end-Permian mass extinction.

The Tannuolinidae includes only two known genera—Micrina Laurie, 1986 and Tannuolina Fonin and Smirnova, 1967, both from the Lower Cambrian. They are phosphatic bimembrate small shelly fossils, consisting of two types of sclerites—the mitral and sellate sclerites. These sclerites show basal-internal accretional growth, spaced growth lamellae, carinae (in mitral sclerites of Tannuolina) or teeth (in mitral sclerites of Micrina), and unevenly distributed pores and canals. The scleritome of tannuolinids is poorly known because they are often preserved as disarticulated sclerites. Here we describe Micrina xiaotanensis new species and Tannuolina zhangwentangi Qian and Bengtson, 1989 from the Lower Cambrian Shiyantou and Yu'anshan formations (upper Meishucunian to Qiongzhusian stages) at Xiaotan, eastern Yunnan, South China. The new material not only extends the geographic range of Micrina, previously known only in Australia, but also includes two composite specimens of T. zhangwentangi: one with a pair of dextral and sinistral mitrals juxtaposed along the apertural margin of their decrescent sides, and the other with a smaller sellate ontogenetically merged with the sella of a larger sellate. Perhaps as a result of being contacting or imbricating surfaces, the decrescent, sella, and duplicature sides are also characterized by negative allometry (relative to other sides) and a sparse distribution of pores. The new fossils do not support reconstructions that place a sellate and a mitral sclerite, respectively, at the anterior and posterior end of the Tannuolina animal, in a way similar to Halkieria evangelista Conway Morris and Peel, 1995. Instead, they are consistent with the traditional view that the scleritome of Tannuolina consisted of four anterior-posterior files of sclerites: two opposing mitral rows flanked by two imbricated sellate series. The bimembrate Micrina may or may not have had a similar scleritome. If Tannuolina and Micrina form a monophyletic group outside the total group of brachiopods, then Micrina is likely to have had a multisclerite scleritome similar to that of Tannuolina. This implies that microstructural similarities between the tannuolinids and some linguliformean brachiopods are probably symplesiomorphic or convergent. Alternatively, Tannuolina and Micrina may represent stem groups leading to the linguliformeans while Halkieria represents a stem group leading to the calcareous brachiopods—a radical hypothesis that would imply that the two brachiopod groups independently evolved the bivalved body plan.

Upper Changhsingian strata occur as isolated outcrops in the Malaya Laba and Belaya river basins in the Peredovoy Range of the northwestern Caucasus Mountains and include shelfal limestone, reefal and biohermal buildups, and terrigenous clastics, here placed in the Belalabinskaya Group. These lithofacies contain a varied and rich assemblage of brachiopods, bivalves, ammonoids, inozoan sponges, and algae. This biota is Late Changhsingian in age and correlates with similar biotas described in south China, the Pamir Mountains, South Primorye in far eastern Russia, and Transcaucasia. The brachiopod genera and biotic assemblages are very similar to those of the Cathaysian Subprovince of the Tethyan Province. Two new families, Labaellidae and Licharewiconchidae; four new genera, Labaella, Licharewiconcha, Tethysiella, and Nikitinia; a new diagnosis of Caucasoproductus; and four new species of brachiopods, Rhipidomella caucasica, Cathaysia caucasica, Nikitinia licharewi, and Licharewina praetriassica, are described. One new genus and species of ammonoid, Neoglassoceras caucasicus, and one new species of bivalve, Claraioides labensis, are described.

Molecular clocks can provide insights into the evolutionary timescale of groups with unusually biased or fragmentary fossil records, such as birds. In those cases, it is advantageous to establish internal anchor points—molecular time estimates—using the best external fossil calibrations. In turn, those anchor points can be used as calibrations for more detailed time estimation within the group under study. This method also avoids the inherent problems in drawing conclusions about the evolution of a group based on data tied to the poor fossil record of that same group. The galliform-anseriform divergence (∼90 million years ago) is an example of such an ideal anchor point for molecular clock analyses in birds.

The Middle Triassic bivalve genus Daonella Mojsisovics, 1874a has great potential for biostratigraphic correlation but a coherent systematic classification is still lacking. Many taxonomic characters previously used for Daonella classification depend on preservation and ontogeny, or intercorrelate strongly. The subgenus Daonella (Arzelella) Turculet, 1972 is revised on the basis of newly defined taxonomically significant characters and principle component analysis (PCA). Several species of this subgenus have been previously discriminated by characters taxonomically irrelevant such as the costae-free triangular fields adjacent the hinge (dependent on preservation), or they represent juvenile growth stages, which for instance show a more elongate shell form and no trifurcation of primary costae.

The use of this new systematic approach permits synonymy of many species with local distributions. The following species are considered as junior synonyms of D. (A.) tyrolensis Mojsisovics, 1874a: D. anastasiui Kittl, 1908; D. arzelensis Kittl, 1912; D. badiotica Mojsisovics, 1874a; D. loczyi Kittl, 1912; D. parthanensis (Schafhäutl, 1863) partim; D. cf. tyrolensis Kittl, 1912; and D. tripartita Kittl, 1912. Additionally, D. imperialis Kittl, 1912 is considered a junior synonym of D. (A.) taramellii Mojsisovics, 1874a. D. desecata (Schafhäutl, 1863) and D. frami Kittl, 1907 have been excluded from the subgenus Daonella (Arzelella). With knowledge of precise stratigraphic distribution in classical sections, a detailed supraregional biostratigraphic correlation becomes possible, in particular for the Southern Alps of Europe.

Many bivalves and brachiopods possess multilayered shells. In one such bivalve, Mytiloides ipuanus (Wellman, 1959) (Inoceramidae), the mineralized shell comprises an outer prismatic calcite layer and an inner nacreous aragonite layer. Each of the three shell surfaces—the external, internal, and shell layers' interface—has a distinct sculpture. Pronounced costae on the shell interface are “cryptic” in the sense that, in life, they would have been barely expressed on the internal surface and only expressed as comparatively weak, broad, rounded costae on the external surface. In fossil specimens, depending on the timing of shell dissolution relative to compaction and lithification, any of these sculptures may be preserved and combined in various ways on simple or composite surfaces/molds. Many of the resulting specimens appear to be morphologically quite distinct from each other. The form and distribution of particular “taphomorphs,” however, can be predicted from a knowledge of shell mineralogy and taphofacies. The different sculptures present on the three shell surfaces, and their wide range of taphonomic expressions, had not been recognized previously, resulting in the erection of three nominal taxa for this single species, based on different taphomorphs. It is not clear whether similar problems remain undetected in other multi-shell-layered invertebrate fossil groups.

The Artinskian Metaperrinites and Kungurian Perrinites faunas are recognized from the Ratburi Group of the Loei area, northcentral Thailand, and the Saraburi Group of the Saraburi area, southcentral of the country, respectively. They represent one of the chains of the Asia-European perrinitid belt that was distributed within the ancient Tethys from Crimea in the west to Timor in the east. A total of 14 species representing 11 genera in the perrinitid faunas are illustrated and described herein.

Two new species of gastropods belonging to the volutid genus Adelomelon Dall, 1906 are described from Tertiary strata of Patagonia, Argentina. Adelomelon posei n. sp. was found in the lower part of the Gran Bajo del Gualicho Formation (Río Negro Province), which is currently dated as Late Eocene through Middle Miocene in age. Adelomelon valdesiense n. sp. comes from the Puerto Madryn Formation (Chubut Province) of early Late Miocene age. Both species are characterized by angulated biconical teleodonch whorls and strongly developed rows of axial nodes, similar in shape to those of some Recent species of Adelomelon, but positioned differently. Discovery of two new species of the genus Adelomelon in the Tertiary of Patagonia significantly extends the known stratigraphic range of this genus from Late Eocene(?)—Miocene to Recent.

A rich collection of Brachyura from the famous Cenomanian “Fish Beds” of western Lebanon has permitted the reevaluation of several families of decapod crustaceans during an important period of their evolution. The new subfamily Telamonocarcininae is erected to include the most primitive known dorippids, which possess a rostrate carapace and a mixture of characters present in the two modern subfamilies Dorippinae MacLeay, 1838 and Ethusinae Guinot, 1977. Telamonocarcininae new subfamily includes the three genera, Telamonocarcinus new genus, Eodorippe Glaessner, 1980b, and Tepexicarcinus Feldmann, Vega, Applegate, and Bishop. 1998. Telamonocarcinus n. gen. exhibits the last two pair of pereiopods reduced and carried in a subdorsal and/or dorsal position.

The new genus Corazzatocarcinus, belonging to the Necrocarcinidae Förster, 1968, is here erected; C. hadjoulae (Roger, 1946) n. comb., the type species of the genus, is redescribed and a lectotype is here selected. The observation of preserved pereiopods, especially the reduced and dorsal last pairs, in many specimens of C. hadjoulae, together with new interpretations of already published data, has permitted questionable placement of the Necrocarcinidae in the Podotremata sensu Guinot and Tavares, 2001.

The discovery of a specimen attributed to Homolopsis aff. edwardsii Bell, 1863 adds to the understanding of the anatomy and distribution of Cretaceous homolids, seldom reported in Southern Tethys deposits.

The systematic position of endemic Early Miocene pectinid taxa of Patagonia contained in the uppermost horizons of the San Julián and Monte León formations and in the basal and middle beds of the Chenque Formation is revised. Two new genera are proposed: Reticulochlamys new genus with R. proximus (Ihering) as its type species and Jorgechlamys new genus with J. juliana (Ihering) as its type species. Two new species are described: Reticulochlamys zinsmeisteri new species from the Monte León Formation and Reticulochlamys borjasensis new species from the Chenque Formation.

Many of the late Neoproterozoic “Ediacaran fossils” have been referred to the Cnidaria, often on the basis of vague or poorly known features. However, representatives of the living Chondrophorina (=Porpitidae, Hydrozoa), Pennatulacea (Anthozoa), and Coronatae and/or Stauromedusae (Scyphozoa) have all been identified in Ediacaran biotas, based on specific morphological features preserved in a number of specimens. These three cnidarian groups have plausible Paleozoic representatives as well, but many of their Paleozoic fossils are also somewhat problematic. We test these systematic hypotheses by using them to calibrate divergence dates across the Cnidaria, based on an extensive molecular phylogeny of extant cnidarians. In this reductio ad absurdum approach, if a calibration based on one interpretation of a problematic fossil yields a glaringly inconsistent age for a better-known clade, that interpretation is likely to be mistaken. We find that assuming the existence of Pennatulacea and Scyphozoa in the “Ediacara biota” places the root of the Cnidaria between 800 and 1,000 Ma, a figure which is, at least, not out of line with other molecular clock estimates. However, assuming the existence of the Chondrophorina in the Neoproterozoic, or anywhere in the Paleozoic, pushes the root of the Cnidaria back to between 1,500 and 2,000 Ga, which is considerably older than the oldest previous estimates for the origin of the Cnidaria. We suggest that the likeliest explanation is that chondrophorines were not present in the late Precambrian or Paleozoic. The Ediacaran and Paleozoic fossils previously interpreted as chondrophorines probably represent other taxa.

A limestone block in the Shirokawa-Nomura area of western Shikoku (Japan) is interpreted to have been originated as a Panthalassan seamount, and is assigned to the northern part of the Southern Chichibu Terrane. The Late Permian foraminiferal fauna from this block is composed of 33 species, and is characterized by Nanlingella? sp., three unidentified species of Staffellidae, Paraglobivalvulina mira, Dagmarita chanakchiensis, Paradagmarita sp., and Partisania sp. Among them, four unidentified species are systematically described and discussed. Although this fauna is indeterminately either Wuchiapingian or Changhsingian, it is clearly Late Permian in age by comparison with Late Permian faunas in the Tethyan regions, and by the complete absence of neoschwagerinids, verbeekinids, and schwagerinids, which became extinct by the end of Middle Permian time. The limestone block in the Shirokawa-Nomura area is clearly distinguished from Upper Permian shelf limestones from the Kurosegawa, Southern Kitakami, and Maizuru terranes by its lithology and by the complete absence of the foraminifer Colaniella, one of the most important index genera in Upper Permian strata throughout the Tethyan and peri-Gondwana regions.

Cambrian ptychopariids have defied most attempts at higher classification. Even at the generic level, there is no consensus as to what constitutes identification criteria in these morphologically conservative trilobites. The problem is more acute when there is a lack of knowledge about the different sclerites of species, the presence of species with morphologies intermediate between two genera, the naming of genera where incompletely known or poor quality specimens were used for type species, and the use of character checklists to generate diagnoses for higher taxa. This study on the kochaspid trilobites (Lower to Middle Cambrian) uses several available representatives of each genus to alleviate or assess some of these problems. Successive reweighting of characters is used for the assessment of 70 characters among 66 taxa as to their importance in forming clades. Results of this study include five important points about ptychopariid classification: 1) knowledge about noncranidial sclerites is important for the proper placement of taxa that have generalized morphologies; 2) in contrast, taxa that have more derived cranidial morphology can be accurately placed within a clade; 3) intermediate morphologies illustrate a close link between genera, but these forms can present nomenclatural problems in their placement; 4) although genera defined by type species based on incompletely described or poorly preserved specimens can create nomenclatural nightmares, other species assigned to these genera are not dependent on their previous taxonomic assignment for their placement in the cladogram; and 5) checklists of morphological characters cannot be used to recognize ptychopariid groups, since the level of homoplasy is too high and there are too many reversals of character states within a clade. Instead, a list of character states that typify a taxonomic group is more useful and will lead to a more stable classification.

This cladistic analysis of kochaspid trilobites indicates that 64 of the 70 characters were useful in the formation of clades. Fifty-six cranidial, librigenal, thoracic, and pygidial characters were useful in typifying larger and smaller clades. The analysis also indicates that Eokochaspis, Nyella, and Onchocephalus are polyphyletic. Reassignments based on the cladistic analysis include Schistometopus collaris to Caborcella, and Syspacephalus obscurus to Mexicella.

Reevaluation of 21 specimens of Permian crustaceans from near Palermo, Italy, referred to Palaeopemphix Gemmellaro, 1890, has resulted in transfer of the genus from the decapod Crustacea to a new suborder, the Palaeopemphida, and a new superfamily, Palaeopemphidae, of the archaeostracan Phyllocarida.

The Figueroa sulfide deposit located in Franciscan Complex rocks in the San Rafael Mountains, California, contains the only known Jurassic hydrothermal vent community. Based on radiolarian biostratigraphy it is Pliensbachian (early Jurassic) in age. The Figueroa fossil organisms lived at a deepwater, high temperature vent site located on a mid-ocean ridge or seamount at an equatorial latitude. The vent site was then translated northeastward by the motion of the Farallon Plate and was subsequently accreted to its present location. The vent fossils are preserved as molds of pyrite and there is no remaining shell or tube material. The fossil assemblage is specimen rich, but of low diversity, and comprises, in order of decreasing abundance, vestimentiferan worm tubes, rhynchonellide brachiopods (Anarhynchia cf. gabbi), and trochoidean gastropods (Francisciconcha maslennikovi new genus and species). These fossils represent only primary consuming organisms, some of which may have had chemosynthetic microbial endosymbionts, like many modern dominant vent animals. The Figueroa vent assemblage shares vestimentiferan tube worms and gastropods with other fossil and modern vent communities, but is unique in having rhynchonellide brachiopods. It shares this feature with contemporary Mesozoic cold seep communities. Many other taxonomic groups found at modern vent sites are missing from the Figueroa assemblage. The presence of vestimentiferan tube worm fossils in the Figueroa deposit is at odds with the supposed time of origin of the modern vestimentiferans (∼100 Ma), based on molecular data.