New collections of fossil sponges have been recovered from Devonian to Upper Carboniferous sections of Spain. These include two new hexactinellids from Devonian rocks of northwestern Spain: the small globular protospongiid Iberospongia globulara new genus and species, and the much larger, bowl-shaped, pelicaspongiid Asturiaspongia aqualiforma new genus and species. The three specimens of Asturiaspongia n. gen. were collected from the calcareous member of the Aguión Formation, of late Emsian age, at Arnao Beach, Asturias. This member has been interpreted as a developing patch reef. The single specimen of Iberospongia n. gen. was collected from late Zlichovian (Emsian) beds of the Cortés Member of the Abadía Formation, near Polentinos, Palencia. These beds represent the beginning of the transition to deeper water that took place during the Emsian and which lasted throughout the Devonian.

Lower Carboniferous sponges have been collected from southern Spain. The hexactinellid Estrellaspongia irregulara new genus and species, is a thick-walled, basin-shaped pelicaspongiid with irregular, branched, inhalant canals and coarser irregular canals in a skeleton of irregularly oriented and spaced small hexactines. It is from late Viséan rocks of Sierra de la Estrella, near Espiel in Córdoba. The reticulosid Stereodictyum orthoplectum Finks, 1960 was collected from Viséan beds at Las Pilitas 2, Badajoz. It has a body wall of alternating layers of regularly spaced vertical and horizontal bundles of spicules in the quadrate-appearing skeleton. This is the first report of the genus from Europe and it is the oldest known occurrence of the genus.

Upper Carboniferous sponges, Bashkirian to Moscovian-Kasimovian, have been collected from northern Spain. Demosponges include: Heliospongia excavata King, 1933; Coelocladia spinosa Girty, 1908; small generically unidentifiable anthaspidellids; Haplistion Girty, 1908 sp. 1 and sp. 2; and a small fragmentary monaxonid demosponge of uncertain taxonomic assignment. Hexactinellida include the reticulosids, Stioderma perforata new species, and Stioderma Finks, 1960 sp. A, and the new amphidiscosids, Ascospongiella capdevilae new genus and species and Hadrophragmos soleniscus new genus and species. Root tufts A, B, and C are of uncertain taxonomic assignment.

The Neoproterozoic Ediacara biota at Mistaken Point contains the oldest diverse Ediacaran assemblages and is one of the few known deepwater localities, yet the biota is dominated by endemic forms, nearly all of which remain undescribed. Thectardis avalonensis new genus and species, one of these endemic forms, is a cm-scale triangular fossil with a raised rim and a featureless-to-faintly-segmented central depression. More than 200 specimens occur on two bedding plane surfaces: the 565 Ma E surface and the 575 Ma Pigeon Cove surface, nearly 2,000 m lower in the succession. Morphological and taphonomic data suggest that the organism was an elongate cone that may have lived as a suspension-feeding “mat sticker” with its pointed base inserted into the microbially bound sediment. If true, Thectardis n. gen. would be the tallest-known mat sticker, reaching a maximum height of over 15 cm. Specimens display little ontogenetic change in length:width ratio, suggesting that Thectardis grew uniformly by incremental addition of material to its distal end. Morphological differences between specimens at two well-separated stratigraphic levels may have resulted from evolutionary or ecophenotypic variation.

Charniodiscus is a leaf-shaped Ediacaran (terminal Neoproterozoic) fossil with a worldwide distribution, but the scarcity of complete specimens has previously hindered evaluation of its taxonomy and ecology. The presence of hundreds of complete (fronds with stem and disc attached) Charniodiscus specimens from the Avalon Zone of Newfoundland has allowed for detailed morphometric analysis of Charniodiscus specimens and permits determination of characteristics which vary with growth (e.g., stem length, frond width, and disc diameter) versus those that reflect taxonomic differences (e.g., number of primary segments, presence of a distal spine, shape ratios). This has led to the recognition of three species of Charniodiscus in the Mistaken Point biota, including numerous specimens of two new taxa, C. procerus n. sp. and C. spinosus n. sp., and rare specimens of the Australian species C. arboreus. C. procerus n. sp. and C. spinosus n. sp. represent similar, yet ecologically distinct forms of upper-level filter feeders with diverging feeding strategies in order to reduce the competition for resources. Ratio plots and principal components analyses (PCAs) confirm the existence of five (possibly six) morphologically distinct species of Charniodiscus worldwide.

Traditionally, deep time was the domain of paleontology. Origination time could be assessed only through reference to first appearance data in the rock record. This changed almost from the beginnings of modern molecular biology, when it was realized that molecules could be used to calculate divergence times between living species. Early studies relied on immunological distance information, and the underlying rationale was simple: because evolution involves changes to the genetic code, and because these changes accumulate over time, we should expect the number of accumulated changes (the molecular distance) between living taxa to increase as their time of divergence becomes older (Zuckerkandl and Pauling, 1962). By inferring a rate of evolution of the genetic code, we can place absolute time estimates on divergence points.

Paleozoic lagenide foraminifera are strikingly similar morphologically to Mesozoic and Cenozoic Lagenida, but because benthic foraminifers suffered a catastrophic reduction in diversity during the end-Permian mass extinction, it is unclear whether the similarities of Paleozoic lagenides and younger unquestioned Lagenida link them evolutionarily or are the product of convergence. Seven species representing five families of Paleozoic lagenide foraminifers were examined and found to possess mostly monolamellar hyaline-radial walls, as in extant nodosariid Lagenida. Exceptions are Protonodosaria rauserae Gerke, 1959, whose wall is not optically radial, and Syzrania amazonica Altiner and Savini, 1997, whose hyaline-radial wall may or may not be accompanied by a secreted inner microgranular layer. The inner microgranular layer is an element that is thought to have been inherited from the ancestral Fusulinida. Its absence in all but the earliest and morphologically simplest Paleozoic lagenides indicates more advanced wall structure than generally has been ascribed to this group. The wall in Pachyphloia spp. is secondarily thickened, suggesting plesio- or ortho-monolamellar construction, whereas other examined species exhibit atelo-monolamellar wall structure. These types of lamellarity are common among modern nodosariids. Thus, on the basis of not only morphologic similarity but also similar wall structure, we strongly suspect evolutionary continuity of lagenides across the Permian-Triassic boundary. The question is not completely resolved, however, because lagenides have not yet been recovered from lowest Triassic rocks.

New and previously described “Sphinctozoan” taxa have been collected from six different localities in northern Spain, all of them dated as Late Carboniferous, from Moskovian to Kasimovian in age. The sphinctozoans in the collection are all assigned to the Demospongiae: a new species of polyglomerate type, Cystothalamia vandegraaffi n. sp., and known species Amblysiphonella barroisi Steinmann, 1882, Amblysiphonella carbonaria (Steinmann, 1882), Discosiphonella mammilosa (King, 1943), Discosiphonella maior (Van de Graaff, 1969), and Sollasia ostiolata Steinmann, 1882. Some of these specimens present interesting paleoecological features, such as the use of a piece of calcareous algae as a hard substrate in a soft muddy bottom and a possible branching pattern determined by photophilic or negative geotaxic growth.

Spicular radiolarians of the family Palaeoscenidiidae were recovered from the Llandovery to lower Wenlock of the Cape Phillips Formation, Nunavut, Canada. Several changes are made to the classification of these radiolarians. Goodbodium rarispinosum (Goodbody, 1986) was previously placed with Palaeoscenidium Deflandre, 1953. Insolitignum MacDonald, 1999 is emended to allow for additional apical rays. Insolitignum cancellatum (Goodbody, 1986) includes species which were previously assigned to Palaeoscenidium, Palaeotripus Goodbody, 1986, and Palaeoephippium Goodbody, 1986, owing to the variable development of one ray. Insolitignum peranima MacDonald, 1999 is synonymized with I. dissimile (Goodbody, 1986). Palaeodecaradium apertum (Goodbody, 1986) was previously placed with Palaeoscenidium; Palaeotripus nudus Goodbody, 1986 is considered a synonym of P. apertum. Palaeoephippium is rediagnosed based on the branching of the basal rays; the new diagnosis also allows for more than six rays and in orientations other than originally diagnosed. Palaeoephippium aranea Goodbody, 1986 is a junior synonym of P. bifurcum Goodbody, 1986. Palaeoephippium reteforme Goodbody, 1986 and P. ramipendentes Goodbody, 1986 are synonymized with P. radices Goodbody, 1986. Palaeotripus monospinosum Goodbody, 1986 is synonymized with Palaeoephippium spinosum Goodbody, 1986. One new species, Palaeodecaradium gordoni, is described. It possesses six rays; the apical rays are long and curved. The basal rays bear spinules on their lateral margins.

The phylogenetic significance of archeopyles in calcareous dinoflagellates cysts has been evaluated, and a classification model is developed that focuses on the archeopyle categories and types established for organic-walled dinoflagellates by Evitt (1967, 1985). Several of Evitt's archeopyle categories are presently recognized within the calcareous dinoflagellate cysts: apical, intercalary, and combination archeopyles, which are here subdivided into eight archeopyle types and several variations. Archeopyles that cannot be assigned to a distinct type, and those with outlines that do not allow an accurate interpretation, are together placed in a separate category: miscellaneous archeopyles. The stratigraphic distribution of the different archeopyle types reveals a phylogenetic trend characterized by an increase of the number of plates involved in archeopyle formation. The first calcareous dinoflagellate cysts to appear in the late Triassic have a monoplacoid apical archeopyle. The first taxa that show an archeopyle involving more than one plate are from the Early Cretaceous, with the first triplacoid apical archeopyle appearing at the Berriasian/Valanginian boundary. This is followed by the first combination archeopyle, which includes six plates, in the middle Aptian. Epitractal archeopyles originated no earlier than the early Oligocene. At the beginning of the Paleogene, species with a combination archeopyle increased in abundance, progressively replacing species possessing an apical archeopyle that dominated during the Mesozoic. Newly described species are: Calciodinellum clamosum, accommodating the two subspecies Calciodinellum clamosum subsp. clamosum Autonym, and Calciodinellum clamosum subsp. latum; Calciodinellum kerguelense; Fuettererella belliata; and Pernambugia? patata. New combinations are: Cervisiella operculata (Bramlette and Martini, 1964); Praecalcigonellum sulcatum (Keupp, 1979a); and Praecalcigonellum dolium (Keupp, 1979b). Because of the new interpretation of their archeopyles we emend the following genera: Cervisiella Hildebrand-Habel, Willems, and Versteegh, 1999; Echinodinella Keupp, 1980; Fuettererella Kohring, 1993a; and Pernambugia Janofske and Karwath in Karwath (2000). The species Orthopithonella? minuta and Pirumella johnstonei, which have been previously synonymized with Fuettererella deflandrei, are retained as independent taxa.

New collections from measured sections provide much of the material for this study. Holcocystis, Atopocystis, and Stummelasma are erected as new genera. Atopocystis mucronata and Stummelasma sulfurense are new species; Holcocystis flexa (Stumm), Stummelasma lonense (Stumm), and S. antelopense (Merriam) are new combinations. Revised coral ranges are integrated with the standard Nevada conodont zones and brachiopod-based faunal intervals. A range chart for 33 Rugosa emphasizes their value for correlation in Icriodus, or brachiopod-poor biofacies of the Great Basin. It also shows that full recovery from the end Lockhovian/early Pragian coral crisis in the region was delayed until the start of the middle Emsian gronbergi Zone. The recovery was accomplished principally by radiation of the Breviphyllidae and Papiliophyllidae, and by immigration of cyathophyllid and other genera.

Updated lists of Rugosa genera present in the Great Basin, Mackenzie, and Appohimchi provinces during the Pragian and early Emsian (kindlei-lenzi zones) and middle to late Emsian (gronbergi-serotinus zones) are given. Qualitative and quantitative data, the latter as Otsuka Coefficients, indicate that the Pragian Great Basin coral faunas can no longer be regarded as part of a temporary westward extension of the Eastern Americas Realm. Nor can they be considered part of the Mackenzie coral province. Genus absence/presence data show that the Great Basin coral province began with a slow recovery of faunas after the late Lochkovian/early Pragian coral crisis, and ended with the arrival of typical Old World Realm families, including the Ptenophyllidae and Stringophyllidae, within the early Eifelian, costatus Zone. During this time faunas of the Mackenzie coral province were also distinct from those of the exotic Alexander and Farewell terranes of Alaska and British Columbia. The duration of the Devonian Great Basin coral province corresponds closely to the duration of a period of depressed seawater temperatures postulated from the distribution of gypidulinid brachiopods.

New dinoflagellate cyst taxa have been recovered from Pliocene deposits in the Antwerp area of Belgium, where a detailed analysis of the Kattendijk and Lillo formations has yielded a diverse dinoflagellate record for the southern margin of the North Sea Basin. Four new species and two new genera of dinoflagellate cysts are recognized: the gonyaulacaceans Spiniferites coniconcavus n. sp. and Pyxidinopsis braboi n. sp., the goniodomacean Desotodinium wrennii n. gen. and sp., and the protoperidiniacean Scaldecysta doelensis n. gen. and sp. The protoperidiniacean genus Barssidinium Lentin, Fensome, and Williams, 1994 has been emended from new observations on the tabulation of Barssidinium pliocenicum (Head, 1993) Head, 1994a emend. The excellent preservation of the Belgian material accounts for these new observations. Barssidinium wrennii Lentin, Fensome, and Williams, 1994 is considered a taxonomic junior synonym of Barssidinium pliocenicum (Head, 1993) Head, 1994a, which thus becomes the correct name for the type of the genus. The new marine incertae sedis palynomorph Waaslandia geminifera n. gen. and sp. is also proposed.

Because more than one calibration is used, quartet dating (a molecular dating method) is thought to reduce error that might arise from a single calibration point. Within crocodylians, there is a strong correlation between calibration age and divergence estimate for five mitochondrial genes and one nuclear gene—estimates based on two Neogene calibrations are all younger than those based on two Paleogene calibrations, and estimates based on one Neogene and one Paleogene calibration are of intermediate age. Confidence limits on the youngest estimates exclude the oldest estimates, and in several cases they exclude known minimum divergences from fossil occurrences. Addition of time to the calibrations improves among-quartet and stratigraphic consistency, but not all kinds of modifications have the same impact; addition of uniform blocks of time to all calibrations efficiently increases among-quartet consistency, but with range extensions that more than double some of the Neogene calibrations. Modest increases in calibration age disproportionately impact divergence estimates based on later calibrations. Some among-quartet disparity might reflect calibration error, especially among caimans, but some range extensions necessary to improve consistency are unreasonably long. Quartet dating appears to systematically undercompensate branch length error with late calibrations and overcompensate it with early calibrations, but in all cases very reasonable results—alligatorid-crocodylid divergence in the Late Cretaceous and Alligator-caiman divergence at or near the Cretaceous-Tertiary boundary—are obtained when both a Neogene and a Paleogene calibration is used. This suggests that, given current likelihood models, the use of calibrations sampling different parts of a clade's history is the best strategy when using quartet dating.

The Pacific Slope of North America's paleontologic record of Paosia, a nearshore-marine, pseudomelaniid gastropod primarily associated with the Old World Cretaceous Tethyan realm, is established for the first time. Former workers have almost universally referred to this genus by its junior synonym name Trajanella Popovici-Hatzeg, 1899. Six species, including Paosia pentzensis new species, are recognized, and all are from siliciclastic facies. Their documentable geologic range is late early Albian to early Campanian. Four of the five previously named species were misallocated to genus Acteonina and one was placed in genus “Trajanella.”

Paosia originated in western Europe and in the Caucasus Mountains region during the latest Jurassic (Tithonian). It arrived in the study area, possibly in the Aptian, but certainly by the late early Albian and, most likely, by way of Japan and the north Pacific gyre. Worldwide, the genus had its peak diversity during the Albian and Cenomanian. The only other Western Hemisphere records of Paosia are a species from the Campanian of Jamaica and a possible species from the Coniacian of Texas. Paosia had a preference for tropical waters, but its presence in the study area indicates that it could live in temperate-tropical transition areas.

Most of the Pacific Slope of North America species are represented by a few specimens, but when plentiful, they display variability in overall shape between juvenile and adults, with the last whorl of the adults becoming more cylindrical with growth.

Paosia kollmannii new name is proposed for the homonym Trajanella acuminata Kollmann, 1979.

Stegerhynchus was perhaps the most common rhynchonellide brachiopod in the Early Silurian (Llandovery) postextinction brachiopod fauna of North America. In shell morphology, it closely resembles the Late Ordovician rhynchonellide Rhynchotrema in having a rostrate shell posterior and simple, strong costae. It differs internally from Rhynchotrema primarily in having a much-reduced septalium (=cruralium). Superficially Stegerhynchus has a conservative, typically simple, rhynchonellide morphology, but detailed biometric analysis of large samples from the >400 m-thick Llandovery (mid-Aeronian to mid-Telychian) tropical carbonate succession of Anticosti Island reveals that the genus underwent significant evolutionary and ecophenotypic changes over about five million years. The shell length/width ratios of Stegerhynchus peneborealis from sediments of a low-energy, muddy substrate tend to be lower than those of S. deltolingulatus new species from high-energy, reef or inter-reef settings. A wider shell and hingeline probably had a greater stability on the soft seafloor. Also a wider shell appears to be associated with a larger (relative to shell size) sulcus size at the anterior margin. The changes in relative sulcus size either represent ecophenotypic variation in response to environmental conditions, or a random effect of evolutionary selection through time. Both multivariate and single-character analyses demonstrate that two important biometric features, the apical angle and shell flank rib number, separate all forms of Anticosti Island Stegerhynchus (middle Aeronian to middle Telychian) from the widely cited European species Stegerhynchus borealis (latest Telychian-Wenlock) from the type area of Gotland, Sweden. The temporal changes of these two characters are interpreted to be evolutionary modifications.

Four shell types are recognized from strophomenide brachiopods from Anticosti Island based on their fibrous or laminar character and on the type of taleolae. The shell types consistently co-vary with the types of cardinal process and style of socket plates. Treating shell structure as a conservative, non-reversing character implies that there are four groups of strophomenide brachiopod. The laminar-shell strophomenoids probably originated two separate times; one origination giving rise to two groups within the Strophomenida and one origination producing the Orthotetida. This matches the Treatise classification with only minor variation. The fourth group, that with fibrous shell and trilobed cardinal process and which includes the Plectambonitoidea, does not clearly fit into the Strophomenata and may be more closely related to the Clitambonitoidea. A limited cladistic analysis supports the idea that shell structure should be an important factor in establishing evolutionary kinship and points to ways of optimizing the Treatise classification.

Detailed analysis of certain growth characteristics in Trabeculites maculatus contributes to an understanding of the paleobiology and phylogeny of early tabulate corals. Some coralla of T. maculatus contain peculiar, vertically oriented cylindrical lacunae (open areas) that are lenticular, or in one case circular, in cross section. The nature of these structures and their relation to adjacent corallites suggest that they were formed by the coral in response to soft-bodied biotic associates of unknown taxonomic affinity.

Trabeculites maculatus is an unusual tabulate coral featuring both axial and lateral modes of corallite increase. Axial increase was common, often occurring in association with rejuvenation following injury and less commonly involving normal, undamaged corallites. Lateral increase of normal corallites was typical, but this form of increase could also be involved in the termination of lacunae and occurred in response to a divergent growth pattern around the circular lacuna. Corallite decrease was fairly common, usually taking place adjacent to lenticular lacunae but in some cases involving normal corallites not associated with lacunae. Corallite fusion was uncommon; it could be either temporary or permanent. Conspicuous relocation of corallites and restructuring of corallite arrangement generally involved mass rejuvenation and/or regeneration, usually over a large surface area of the corallum.

The growth features in T. maculatus are fundamentally the same as those in the co-occurring Saffordophyllum newcombae, including types of axial increase unknown in other tabulate corals. The basic paleobiologic similarity of these species supports the interpretation that the genera they represent are closely related phylogenetically. The relationship of these taxa to other tabulates, however, remains unresolved.

Small silicified anthaspidellid sponges identified as Gallatinospongia conica Okulitch and Bell, 1955 are described for the first time from the Upper Cambrian of the Great Basin where the sponges are found in situ within dendrolitic microbial reefs. This association forms the oldest anthaspidellid-microbial reefs of Laurentia.

A molecular survey of animal phylogeny (Wray et al., 1996) recovered the presumed correct temporal order of the phylogenetic splits Protostomata-Deuterostomata, Echinodermata-Chordata, and Agnatha-Gnathostomata in studies of six of seven gene sequences. This result raised the question of how this order could be recovered if all of the phyla had appeared in a Cambrian “explosion” of less than 10 m.y., given the expected erratic nature of the molecular “clock.” We simulated trees, and molecular sequence evolution along the trees, under different evolutionary radiation scenarios, with different periods of radiation, relative to times of subsequent evolution. Simulations and phylogenetic analyses of sequences derived from a simulated “Cambrian explosion” of 10–35 million years did not allow the successful recovery of the correct tree, using neighbor-joining, maximum likelihood, or parsimony methods. Success in recovering phylogenies under a Cambrian divergence scenario (520 million years ago) did not exceed 80 percent without an extended divergence time interval of at least 100 m.y. An increased substitution rate during the initial radiation improved the ability to recover correct phylogenies, especially when the rate was 8–10 times the rate following the radiation. Our results militate against the likelihood of an Early Cambrian or slightly longer explosion of the animal phyla, as apparently supported by the fossil record. Some limitations to these conclusions are discussed.

We compare cladistic, phenetic, stratophenetic, and typological methods of recognizing species within a single well-sampled, long-lived Ordovician bryozoan genus, Peronopora Nicholson, 1881. A consensus of 11 methods recognizes 14 species within Peronopora, each of which has both cladistic and phenetic support, and support by at least four different methods. Comparison of methods was based on: 1) the number of species recognized; 2) the degree of splitting of consensus groups; 3) consistency in determining first and last appearance datums, and stratigraphic ranges; 4) consistency in the number of specimens assigned to species; 5) stability in recognizing geographic distributions; and 6) correlations with character heritability. The five methods most closely approaching consensus were: 1) Ward clustering on Euclidean distance; 2) K-means splitting; 3) Ward clustering on correlation coefficients; 4) cladistic parsimony; and 5) cladistic parsimony plus iterative discriminant analysis. The three methods farthest from consensus were: 1) stratophenetics; 2) average linkage on Euclidean distance; and 3) conventional typology. Cladistic parsimony is the only method that can recognize all 14 consensus clusters. We argue that the overall advantages of parsimony analysis outweigh the merits of the various phenetic approaches in recognizing paleontological species. We also argue that given sufficient allochrony in sampling, cladistic structure is detectable both within and among species. Recognizing species based on fixed character states would require at least 72 species in our material.

The crown groups of Pachut and Anstey (2002) are herein recognized as monophyletic species in the sense of Mishler and Theriot (2000), one of which we designate as a new species, P. browni. Six of our eight nonmonophyletic stem groups are recognized in this paper as metaspecies in the sense of Donoghue (1985) and Gauthier et al. (1988). Two of our stem groups are phenetically indistinguishable from phyletically contiguous crown groups, and we attribute the failure of parsimony analysis to recognize the monophyly of these groups to homoplasy.

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.