Paleontological study of 16 samples from four sections through the Silurian-Devonian marine deposits of the Hodh region establishes the development of the Middle Devonìan and adds to our knowledge of the Paleozoic sequence in the West African platform. Above Silurian deposits locally dated by graptolites from the Llandovery, Devonian shales yield an abundant although low diversity benthic fauna, which is assigned to a Givetian age. The brachiopod fauna shows strong affinity with the NE Americas Realm. Two new species are described, Arcuaminetes deynouxi and Eleutherokomma monodi. The revision of the Devonian fauna of the Hodh area supports: 1) the apparent lack of Lower Devonian deposits; 2) the Givetian age of the Devonian succession; and 3) the strong eastern Americas Realm affinity of the fauna, as previously established for the Mauritanian Adrar area.

Despite their importance in breaking down lignified tissue today, much is still unknown about the role of mites in the fossil record, especially with reference to the Paleozoic–Mesozoic transition. This study examines permineralized peat from three localities in the central Transantarctic Mountains, ranging in age from Permian to Jurassic, for evidence of diversity and abundance of wood-boring mites. Evidence of mites, in the form of coprolites and tunnels in wood and other tissues, was found at all three localities; the Triassic site included more than 10 times as many wood borings as the Permian site. Our results supplement prior evidence of wood-boring mites during the Mesozoic and thereby fill in the known geologic range of this plant/animal interaction.

Anourosoricini are among the most specialized shrews in terms of dentition and mandibular structure, showing carnivore-like specializations such as carnassial function and reduction and disappearance of third molars. The tribe is documented from the Upper Neogene of Europe, Asia, and North America, and from the Quaternary of Asia, where a single relict species has survived until the present day.

The Mediterranean area functioned as a sink area for the Anourosoricini. Their source area was a northern, more humid, and more forested zone extending from France to the Ukraine. Southward-directed range shifts resulted in the intermittent presence of the tribe in the Mediterranean region during more humid intervals. The dense Upper Miocene micromammal succession from the Teruel and Calatayud-Daroca basins, central Spain, shows that Crusafontina endemica was present in the area around 10.2 and between 9.7–9.5 Ma. It is succeeded by the dentally more gracile C. fastigata n. sp. at 9.0–8.8 Ma. The larger and more robust C. vandeweerdi n. sp., a form sharing features with Paranourosorex, peaks at ∼7 Ma. The last major acme occurs around 6.3 Ma and is represented by Amblycoptus jessiae. The final disappearance of the tribe from the area takes place at 5–4.5 Ma.

The Anourosoricini provide a well-documented pre-Quaternary example of recurrent climate-controlled north-south range expansion. The proposed paleobiogeographic model presumes that southward mammal migrations are driven by changes in the precipitation regime rather than the temperature regime of the Mediterranean region. A comparison to paleoecological interpretations based on the independent rodent record shows that Anourosoricini avoid areas with low levels of precipitation and low soil humidity. A mean annual precipitation minimum of 600 mm/yr is about the threshold value for populations of the tribe to survive locally.

The available evidence suggests eastward dispersal of a primitive Crusafontina species from Eurasia into North America at about the same time when Hipparion crossed the Bering Strait in a westward direction.

Both ontogeny and sexual dimorphism of the Ostracoda are important for understanding their evolution. The purpose of this study is to evaluate the ontogeny and possible sexual dimorphism, of the ostracode species Paraparchites punctatus n. sp. by assessing size, shape, and ornamentation at the stages of its growth for which we were able to obtain specimens: adults and five or six instars. Brooks's rule suggests that with each molt crustaceans double their volume (Brooks, 1886; Teissier, 1960; see also Przibram, 1931). The degree of adherence to Brooks's rule during ontogeny bears on the importance of heterochrony in evolution. The new species follows Brooks's rule rather closely. Another aspect of morphology investigated herein is sexual dimorphism: although many ostracodes have sexually dimorphic valves and carapaces, this is not true of all species of Paraparchites Ulrich and Bassler, 1906, and some other major groups (Scott, 1959; Moore, 1961).

The chimaeroid fishes enter the fossil record in the Triassic, multiply and diversify to at least 16 genera in the later Mesozoic (Stahl, 1999), and then dwindle during the Cenozoic to only six extant genera (Didier, 1995). Their origin and subsequent evolution have been difficult to trace because, like many other chondrichthyans, their remains consist most often of isolated teeth and fin spines freed and scattered after the cartilaginous skeleton disintegrated. Fossil species are commonly based on dental elements—tooth plates that were not shed like shark teeth but worn at the occlusal surface as they grew slowly from the base throughout life. The entire dentition is known from the extant taxa and from the few fossil specimens preserved with the head intact. It consists of a pair of mandibular tooth plates that occludes with two pairs of plates above, a large posterior palatine pair, and a smaller anterior vomerine pair (for dental terminology, see Stahl, 1999).

This paper offers a preliminary description of a plesiosaur (Reptilia: Sauropterygia) from the Lower Toarcian Posidonienschiefer near the village of Holzmaden in Baden-Württemberg, Germany, and discusses its phylogenetic relevance. This new taxon, Plesiopterys wildi new genus and species, is remarkable in its retention of several plesiomorphic features. A phylogenetic analysis places Plesiopterys as the sister group of the Plesiosauroidea, and as such the taxon is the most basal taxon yet known on the branch leading to this major clade. Plesiopterys possesses a high count of cervical vertebrae and a relatively small head, yet the limbs and limb girdles are plesiomorphic in proportion. The skull displays a mosaic of features, reminiscent of both Thalassiodracon and the rhomaleosaurids in some characters, yet similar to Plesiosaurus in others. The basicranium is plesiomorphic and resembles that of nothosaur-grade sauropterygians in several respects. A faunal comparison between Holzmaden and the Lower Toarcian deposits on the Yorkshire coast of England concludes that the Holzmaden fauna is more plesiomorphic than the roughly coeval Yorkshire fauna in two of three plesiosaur subclades.

A new Middle Permian plant assemblage from South Ash Pasture in King County, Texas, may be the youngest and is certainly the most unusual flora known from the Permian of either West Texas or adjoining north-central Texas. Found serendipitously in the evaporite-rich upper Blaine Formation (Pease River Group, Guadalupian Series), the flora is of very low diversity despite intensive collecting efforts, and the affinities of nearly all taxa are enigmatic. The most common elements are parallel-veined leaves that resemble cordaites but that could be isolated pinnules of a pinnate leaf. Gigantopterid foliage is present but not assignable to any known taxon. A single foliar conifer specimen is too incomplete for assignment. Numerous reproductive organs, however, and an abundance of axes may represent conifers. Conchostracans, palaeoniscoid fish scales, and small heteropolar coprolites also occur in the deposit, which originated as a small, claystone-dominated channel fill in a coastal plain setting.

We present a rank-free phylogenetic nomenclature for 25 well-established ancient clades of living turtles. This is the first attempt to document fully the nomenclatural history of a clade with the intent of proposing a coherent nomenclatural system to replace the traditional rank-based nomenclature. Because of the imperative to retain connectivity to the literature for information retrieval, due consideration is given to balancing the desire to develop a consistent system against the desire to conserve traditional associations between names, taxa (i.e., clades), and characters. Novel issues and problems that emerged during this review include: the unclear name/clade association of traditional names; the creation of synonymy lists from which to choose a name; difficulties associated with selecting a single criterion for choosing among multiple ‘subjectively synonymous’ names; identifying authorship for a converted traditional name; and the potential loss of nomenclatural information due to ‘functional homonyms.’ This work may provide a useful road map to those intent on converting their traditional rank-based nomenclatures to explicitly phylogenetic nomenclatures under the precepts of the PhyloCode.

The late Neoproterozoic Doushantuo Formation in South China contains several exceptionally preserved biotas in its cherts, phosphorites, and black shales (Xiao et al., 1998b, 2002; Zhang et al., 1998). The three taphonomic windows—silicification, phosphatization, and carbonaceous compression—responsible for most of the preservation of nonbiomineralizing organisms in geologic history are all open in the Doushantuo Formation. In combination, these three taphonomic windows have the potential to give us a clearer and more complete picture of late Neoproterozoic biodiversity. Comparison across the three also allows us to evaluate possible taphonomic biases and paleoecological heterogeneity. To accomplish these, however, a more thorough paleontological investigation of each taphonomic facies is necessary.

As recognized by McKenna and Bell (1997), the family Palaeoryctidae (Mammalia: Eutheria) includes three genera, Palaeoryctes Matthew, 1913 (Paleocene and Eocene), Aaptoryctes Gingerich, 1982 (late Paleocene), and Eoryctes Thewissen and Gingerich, 1989 (early Eocene). Each is North American, although Palaeoryctes is said to occur in North Africa as well (Gheerbrant, 1992; however, the classification of the North African species as a palaeoryctid is almost certainly erroneous [personal obsèrvation]), and there are additional, ostensible records of palaeoryctids from Asia, Africa, and Europe that have yet to be described (McKenna and Bell, 1997). In spite of this broad distribution, palaeoryctids are poorly known and documented primarily by isolated teeth, although occasionally better-preserved specimens are found. Palaeoryctids are classified together on the basis of dental resemblances, mostly those of the molars: palaeoryctid upper molars are anteroposteriorly short but transversely wide (especially lingual to the paracone+metacone), the major cusps are tall and pointed, and the paracone and metacone are connate, i.e., they arise from a common base and are joined through much of their height. The lower molar trigonid of palaeoryctids is anteroposteriorly short and the trigonid cusps tall, the talonid tends to be labiolingually narrow and skewed labially relative to the trigonid, and shearing crests are strongly developed on upper and lower teeth. The dental evidence suggests that although palaeoryctids were small in body size, they were predaceous. They probably subsisted on insects and other small terrestrial invertebrates and perhaps even on small vertebrates.

A significant number of small-sized gastropods are described from Emsian (late Early Devonian) strata on the south flank of Limestone Mountain, Medfra B-4 quadrangle, west-central Alaska, providing the first detailed taxonomic inventory of Emsian gastropods from the Farewell terrane of southwestern and west-central Alaska. The fauna is distinctly of Old World Realm character, and contains not a single species in common with Emsian faunas of nearby nonaccreted rocks of western Canada and east-central Alaska (“Western Canada Province” of Blodgett et al., 2001a). The genera Balbinipleura Bandel and Frýda, 1996 and Nanochilina Frýda, 1998, as well as the subgenus Palaeozygopleura (Rhenozyga) Frýda, 2000, are reported for the first time in the Devonian of the Western Hemisphere. The gastropod fauna includes members of three (i.e., Archaeogastropoda, Caenogastropoda, and Heterobranchia) of the five modern gastropod subclasses, illustrating that these gastropod lineages were separated from each other since the Early Devonian. New taxa include the new genera Arctozone, Farewellia, and Medfrazyga, represented by the new species Arctozone cooki, Farewellia heidelbergerae, and Medfrazyga clauticae. Further new species include Quadricarina (Quadricarina?) noklebergi, Balbinipleura krawczynskii, Decorospira lepaini, Decorospira? minutula, Palaeozygopleura (Rhenozyga) reifenstuhli, and Nanochilina gubanovi. In addition, the following previously described gastropods are also discussed and illustrated: Alaskiella medfraensis Frýda and Blodgett, 1998; Alaskacirrus bandeli Frýda and Blodgett, 1998; and Kuskokwimia moorei Frýda and Blodgett, 2001a.

We characterized the skeletal crystallography of representatives of nine rhombiferan, three diploporan, and three paracrinoid species. Crystallographic data from these groups are similar to data from previous studies of crinoids, echinoids, and blastoids in that 1) orientations of c axes are consistent within species and within higher taxonomic groups; 2) c axes typically are oriented subparallel to the medial plane of their respective plates; and 3) the inclination of axes within the medial plane varies between taxa. Rhombiferan c axes are oriented normal to plate surfaces whereas diploporan c axes are tangential to plate surfaces. Paracrinoids more closely resemble diploporans in having irregular patterns of thecal plating but their c axes are approximately perpendicular to plate surfaces as in rhombiferans.

In contrast to c axes, a axes in all specimens show little regularity and cannot be distinguished from random orientations.

The rhombiferan Caryocrinites ornatus displays minor differences in the inclinations of c axes depending on the location of skeletal elements on the theca. Plates at the base of the theca have slightly aborally inclined axes, whereas distal plates have axes inclined slightly adorally. This pattern matches orientations in some early crinoids, suggesting similarities between rhombiferans and crinoids in development or skeletal construction.

Skeletal crystallography in various echinoderms can be compared in light of hypotheses of homology proposed in the Extraxial-Axial Theory (EAT). Skeletal elements homologized under the EAT do not correspond to any particular crystallographic axis orientation, suggesting that the homologies proposed in the EAT encompass significant underlying skeletal variation.

Representatives of the ammonoid family Pronoritidae are ancestral medlicottioideans (Order Prolecanitida) characterized by moderately evolute conch and relatively simple sutures. They comprise the ancestral Pronoritinae, characterized by an undivided dorsal lobe, and the descendant Neopronoritinae with bidentate dorsal lobe. The new genus Paedopronorites is interpreted as the terminal neopronoritin paedomorph. It conforms to the pattern displayed by many late Paleozoic taxa (Glenister and Furnish, 1988a, 1988b), being the geologically youngest representative in the lineage, and characterized by small size, sutural simplification, and low abundance.

Cheirolepidiaceous conifer pollen cones (Classostrobus arkansensis new species) from the Lower Cretaceous (Aptian/Albian) Holly Creek Formation of Arkansas, some still attached to Pseudofrenelopsis parceramosa Fontaine, shoots, bear helically arranged, semipeltate to dorsiventral microsporophylls with abaxially situated pollen masses. The in situ Classopollis Pflug, 1953 pollen and orbicule outer sculpturing consists of short spinules. The abaxial epidermis of the microsporophyll head consists of a stomatiferous central region of isodiametric cells bearing hollow papillae with rounded apices and a nonstomatiferous marginal area of elongate, nonpapillate cells. The head abaxial cuticles are thin relative to those of the shoot internodes. A cutinized hypodermis is lacking. Previously described pollen cones of Classostrobus comptonensis (Alvin et al., 1994) from the English Wealden (Barremian) are also associated with P. parceramosa shoots; however, they differ substantially from the Arkansas cones in possessing peltate microsporophylls with the abaxial surfaces bearing conical papillae, a cutinized hypodermis, and cuticles as thick as those of the shoot internodes. Therefore, at least two morphologically distinct pollen cones were produced on ultimate shoots conforming to P. parceramosa as presently circumscribed. Most cheirolepidiaceous conifers possess extremely thick cuticles on the abaxial surface of the microsporophyll head, which may suggest an unusual pollination biology entailing the production of fewer, relatively long-lived pollen cones. However, the thin cuticles and relatively abundant material of Classostrobus arkansensis n. sp. are more consistent with the typical coniferous pollination system, which includes production of numerous, ephemeral cones. Apparently, the Cheirolepidiaceae possessed a diversity of reproductive strategies.

New material collected from Cretaceous and Tertiary rocks of the Pacific Northwest of North America has prompted a reevaluation of the fossil record of the Homolidae de Haan, 1839 and the Homolodromiidae Alcock, 1900. The fossil records of the homolid genera Homola Leach, 1815; Homolopsis Bell, 1863; and Hoplitocarcinus Beurlen, 1928 are restricted, and Latheticocarcinus Bishop, 1988, which is synonymous with Eohomola Collins and Rasmussen, 1992 and Metahomola Collins and Rasmussen, 1992, is reinstated as a distinctive genus. Thirteen new combinations resulted from reinstatement of Latheticocarcinus: L. adelphinus (Collins and Rasmussen, 1992), L. affinis (Jakobsen and Collins, 1997), L. atlanticus (Roberts, 1962), L. brevis (Collins, Kanie, and Karasawa, 1992), L brightoni (Wright and Collins, 1972), L. centurialis (Bishop, 1992), L. declinata (Collins, Fraaye, and Jagt, 1995), L. dispar (Roberts, 1962), L. pikeae (Bishop and Brannen, 1992), L. punctatus (Rathbun, 1917), L. schlueteri (Beurlen, 1928), L. shapiroi Bishop, 1988, L. spiniga (Jakobsen and Collins, 1997), and L. transiens (Segerberg, 1900). A new species, Latheticocarcinus ludvigseni, is described from Cretaceous rocks of British Columbia. The first fossil occurrence of the extant homolid genus Paromolopsis, P. piersoni new species, is recorded from Miocene rocks of Oregon. Paromola pritchardi Jenkins, 1977 is formally transferred to Dagnaudus Guinot and Richer de Forges (1995) as suggested by Guinot and Richer de Forges (1995). The extinct family Prosopidae von Meyer, 1860 is referred to the Homolodromioidea Alcock, 1900, following previous work. Palehomola gorrelli Rathbun, 1926 is transferred from the Homolidae to the Homolodromiidae, and the new genus Rhinodromia is erected to contain Homolopsis richardsoni Woodward, 1896, from Cretaceous rocks of British Columbia. A new terminology is suggested for describing the rostral area in homolodromiids, in an attempt to alleviate considerable confusion over that issue. The morphologic similarity of fossil and extant members in both the Homolidae and the Homolodromiidae suggest that these two brachyuran families are evolutionarily conservative, much as the lobsters are. In addition, the similar paleobiogeographic and evolutionary patterns seen in the two families suggests that either they are closely related or that brachyuran families exhibited similar evolutionary and dispersal trends early in their history.

A new ichnotaxon, Paradictyodora antarctica, is proposed for complex spreite trace fossils from the Upper Cretaceous of Antarctica and Eocene of Tierra del Fuego, Argentina. This complex, three-dimensional, vertical spreite structure enlarges upwards, displaying a prismatic-to-conical shape that consists of subvertical folded laminae, produced by the lateral migration of a subvertical J-shaped tube anchored at its base. Overall morphology and mode of formation distinguishes this new ichnotaxa from other ichnogenera such as Daedalus, Dictyodora, and Heimdallia. Paradictyodora occurs in fodinichnia-dominated ichnocoenosis developed in distal fine-grained deposits of deepwater fan delta systems.

Acteosaurus crassicostatus Calligaris, 1993 was erected based on a partial skeleton of a small lizard found in marine carbonate rocks from the Cretaceous (Upper Cenomanian-Lower Turonian) of Comen, Slovenia. Here, we show that the holotype and only known specimen cannot be assigned to the genus Acteosaurus (Calligaris, 1993), but instead is referable to and indistinguishable from Adriosaurus suessi Seeley, 1881. Acteosaurus crassicostatus is therefore a junior objective synonym of Adriosaurus suessi.

Remains of a large sea turtle, Terlinguachelys fischbecki n. gen. and sp., were recovered from paralic deposits of the Upper Cretaceous (Campanian) Aguja Formation in Big Bend National Park, Texas. T. fischbecki is a primitive protostegid that retains a constricted humerus, well ossified plastron and costals, prominent retroarticular process on the lower jaw, and long slender femora; however, it has some features, such as a prominent tubercle at the base of the scapular acromion process, found elsewhere only in derived leatherback sea turtles. The unique combination of primitive and derived traits in T. fischbecki illustrates further diversity among Cretaceous sea turtles and another case of parallelism common in sea turtle phylogeny.

Chimaerastacus pacifluvialis, new genus and species, is established on the basis of fossils from the Middle Triassic Liard Formation of northeastern British Columbia. It has well-defined cervical, postcervical, and branchiocardiac grooves; three longitudinal ridges on the cephalic region; and true chelae on the first through third pereiopods. The morphological features of the carapace are a combination of traits used to define both the erymids and the glypheids. A cladistic analysis of 31 decapod genera defines the Astacidea as a monophyletic group, supports the inclusion of the Glypheoidea within the infraorder Astacidea, illustrates the relationships of the Glypheoidea with other astacid groups, and suggests erection of a new family, the Chimaerastacidae, for our new genus and species of decapod. Specimens of C. pacifluvialis are preserved in a sandy bioclastic floatstone that was deposited near the Peace River Embayment in the Middle Triassic. The host lithology suggests that the decapods inhabited a transitional environment between low relief biostromes and the shoreface. This environment provided a unique set of conditions that allowed exceptional preservation of the decapod material.

The Antilocapridae was a diverse artiodactyl family present in some late Tertiary faunas of North America. In México, its Tertiary fossil record is poorly known. The antilocaprid material described in this paper was collected from the early Blancan fluvial deposits of the San Miguel de Allende Area, state of Guanajuato, México. It includes isolated upper and lower premolars and molars, dental series, and some rami fragments. The material is assigned to Capromeryx tauntonensis. The presence of this species in the early Pliocene of central México represents the oldest record in North America and extends its known geographic distribution from the northwestern United States to central México.