Reexamination of the chondrenchelyid Harpagofututor volsellorhinus from the Bear Gulch Limestone (Health Formation, Upper Chesterian, Mississippian), has revealed that the preserved fossil pigments are those originally associated with particular, well-vascularized abdominal organs (liver, spleen, and gonads) and major venous sinuses (orbital, gonadal, pelvic). The pattern of pigment localization reflects circulatory pathways of fossilized vessels. This determination was confirmed by comparison of fossil patterns to the visceral and circulatory anatomy of extant chondrichthyans. The arrangement of these pigments conveys strong, and otherwise unavailable, evidence for the internal reproductive features of these sexually mature, Paleozoic chondrichthyans. Under the appropriate preservational conditions the pigments also reveal asphyxia as the cause of death. Thus, the value of these pigments cannot be underestimated. Unfortunately, they are prone to spontaneous and progressive degradation that starts immediately upon excavation. Consequently, it is imperative to record data accurately and in a timely fashion. This report thus introduces the use of a color flatbed scanner as a particularly effective laboratory research tool for the collection and archiving of ephemeral fossil data.

With the quest for more detailed and precise micropaleontologic data has come a stronger emphasis for quantitative studies of microfossils. Many workers have realized, however, that slide preparation and counting can contribute large errors in quantitative studies (Battarbee, 1973; Moore, 1973; Hattner and Wise, 1980; Laws, 1983).

Representatives of the Ingelarellidae are described from the marine Permian sequences of the Perth, Carnarvon, Canning and Bonaparte Gulf basins of Western Australia. The subfamily Ingelarellinae Campbell (1959) is raised to family status and the new subfamily Notospiriferinae is proposed; content of the Ingelarellidae is reviewed. New taxa described are Tomiopsis notoplicatus n. sp., T. woodwardi n. sp., T. rarus n. sp., T. pauciplicatus n. sp., T. teicherti n. sp., T. globosus n. sp., T. balgoensis n. sp. and T. hardmani n. sp. Additional material from Western Australia belonging to Tomiopsis and possibly Fredericksia is briefly described. Tomiopsis harringtoni n. sp. is described from the southern hills of Buenos Aires (eastern Argentina).

Dinnebitodon amarali, a new genus and species of Tritylodontidae, is described from the Early Jurassic Kayenta Formation of northeastern Arizona. It is distinguished from Kayentatherium wellesi by the possession of three (rather than one) upper incisors and upper postcanine teeth with two (rather than three) lingual cusps.

Liromissus, a new genus of chionine bivalve from the Neogene of Venezuela, serves as an example of the link between geographic range, endemism and extinction susceptibility. Unlike other Neogene tropical American chionine genera, Liromissus was not widespread in the tropical Western Atlantic and Eastern Pacific, but was instead restricted to the Atlantic Gatunian region. Late Neogene extinctions in tropical America affected taxa with restricted geographic ranges, and regions with higher degrees of endemism more severely. Accordingly, Liromissus is the only tropical chionine genus to suffer extinction during the Neogene.

The type species of Liromissus, L. quirosensis, was originally described as a member of the genus Lirophora. Morphological considerations preclude this assignment, but also demonstrate that Liromissus possesses all the characters diagnostic of the Chioninae.

Coniasaurus Owen, 1850 was a small (50–100 cm in length) marine lizard that has been sporadically reported from Late Cretaceous marine deposits of Germany, England, and the United States. These deposits were formed throughout the basins of the Tethys and Western Interior Seas (Diedrich, 1997; Caldwell, 1999; Caldwell and Cooper, 1999; Liggett, 2004). Coniasaurus is thus far known only from incomplete specimens. However, sufficient material exists to show that it possessed four short limbs and an elongated skull, neck, trunk, and tail, and was equipped with a specialized dentition (Caldwell and Cooper, 1999). Caldwell and Cooper (1999) inferred that Coniasaurus likely occupied a niche similar to small sauropterygians.

Morphological and biometrical variability is analyzed in Hipparion primigenium (V. Meyer) from four Vallesian and Turolian locations in Spain (Masía de Barbo, Puente Minero, Nombrevilla, and Los Valles de Fuentidueña). Previously unstudied remains of Hipparion from La Roma 2 (Teruel Province, Spain) are described and tested by multivariate analysis. This form is compared with: 1) Hipparion primigenium (or Hippotherium primigenium) from the above-mentioned Spanish localities; 2) large-sized specimens from Çalta (Turkey) and Pavlodar (Kazakhstan); 3) forms from the locality type of Eppelsheim, Höwenegg, and Dürkheim (Germany), and Nikiti 1 (Greek); and 4) specimens from two other Spanish localities, Concud and Venta del Moro. Hipparion remains from La Roma 2 are identified as Hipparion laromae n. sp. by body mass and morphological characteristics, and confirmed by bivariate and multivariate analyses. The faunal assemblages indicate a late Vallesian age (MN10) for La Roma 2 locality and an early Turolian age (MN11) for the Puente Minero locality.

Palynomorph assemblages recovered from the Kanosh Shale at Fossil Mountain, Utah, are dominated by operculate acritarchs and cryptospores with minor smaller acritarchs. The present findings add new data to the largely incomplete knowledge of Ordovician acritarch assemblages from Laurentia, up to now known only from very few localities in North America. These populations contain some species in common with acritarchs from the Canning and Georgina basins in Australia and with assemblages from China; they indicate a Middle Ordovician (Dapingian-Darriwilian) age. The assemblage is lacking many typical marine acritarchs of this age, which, in combination with some cryptospores, is probably reflecting the likelihood of freshwater influence in the Kanosh Basin. This observation is congruent with previous interpretations of the depositional setting of the Kanosh Shale as a shallow water lagoon that supported the deposition of carbonate hardgrounds.

Four new taxa are described: Busphaeridium vermiculatum n. gen., n. sp.; Digitoglomus minutum n. gen., n. sp.; Turpisphaera heteromorpha n. gen., n. sp.; and Vermimarginata barbata n. gen., n. sp. In addition, the abundance of operculate forms has enabled the revision and a new emendation of the genus Dicommopalla and clarification of the “opalla” complex. We also propose new and revised suprageneric taxa that emphasize inferred biological differences among acritarch genera. The Sphaeromorphitae subgroup is emended to include forms lacking sculptural elements. Two new informal subgroups are proposed: the Superornamenti and the Operculate Acritarchs. Cryptospores are abundant throughout the sections studied and they appear to be more closely related to the late Cambrian Agamachates Taylor and Strother than to Darriwilian and younger Ordovician cryptospores from Gondwana.

New cheirurid trilobite species from the Las Aguaditas Formation in San Juan Province include the Llanvirn Macrogrammus rafi, and the Early Caradoc Ceraurinella zhoui, Nieszkowskia jakei, and N. yongyii. Precordilleran species, such as the Llanvirn Macrogrammus pengi new species from the Gualcamayo Formation, reinforce sinoparapilekiinid affinities for the poorly known Macrogrammus Whittard, 1966, although the monophyly of Sinoparapilekiini requires corroboration. The ontogeny of Ceraurinella zhoui confirms the presence of early protaspid stages for this genus (and Cheirurinae in general). Rare cheirurids include species of Heliomeroides, Pateraspis, and an additional acanthoparyphinid.

Species of the superfamily Acastacea constitute a minor element of North and South American Silurian trilobite faunas. Phacopidina? obsoleta (Ulrich and Delo) (Llandovery, Tennessee) provides the sole Silurian record of the “kloucekiine” grade (Acastacea s.l.); a lectotype is designated for this species. Acaste birminghamensis Norford (mid Llandovery, Alabama) lacks synapomorphies of post-Llandovery Acastidae s.s. (=Acastinae + “Acastavinae” + Asteropyginae), and is the basis for Llandovacaste n. gen. (Acastidae s.l.). A well-preserved sample of Andinacaste cf. A. ledgrandi Eldredge and Braniša from the Catavi Formation (Ludlow–Přídolí), Bolivia, displays apomorphic characters of the genal spines and hypostome shared with Devonian calmoniids. Coaptative structures, including vincular furrow/pits and “bifurcated” thoracic pleural tips, are documented for Andinacaste; similar enrollment morphologies arose in other acastomorph calmoniids. Poorly known Llandovery acastaceans from Paraguay and Venezuela may represent Andinacaste. Acaste zerinae n. sp. from the Pembroke Formation (Přídolí) of Maine is closely comparable to British late Wenlock A. downingiae (Murchison). The Australian Gedinnian acastine placed in Phacopinae indet. longisulcata (Shergold) is designated Acaste lokii n. sp.

Beautifully preserved, isolated and uncompressed plectograptine graptolites from the uppermost Wenlock “Pristiograptus” ludensis Biozone and the lower Ludlow Lobograptus progenitor Biozone are described from the Arctic Islands. Described species comprise Agastograptus robustus Obut and Zaslavskaya from the ludensis and progenitor zones; Agastograptus sp., Gothograptus chainos Lenz, and Plectograptus (Sokolovograptus?) sp., from the ludensis Zone; and Holoretiolites (Balticograptus) erraticus (Eisenack) from the progenitor Zone. The dozens of specimens of A. robustus from one locality are covered with almost continuous periderm and interthecal tissue, a feature rarely seen in plectograptines.

The Florena Shale (Permian, Wolfcampian) of the Midcontinent of North America was deposited in a restricted marine basin. Shifting environments due to marine regression caused a gradual change in the ostracode fauna. Cluster analysis and ordination by nonmetric multidimensional scaling of data on ostracode relative abundances revealed three ostracode assemblages, each characteristic of a different environment. The Cryptobairdia seminalis assemblage from the lowest Florena Shale is characteristic of deeper water, offshore, marine environments with only minor influx of terrigenous mud. The Amphissites centronotus assemblage found above the C. seminalis assemblage occupied a similar environment, but with greater influx of terrigenous mud and intervals of increased turbidity. The Knightina texana assemblage occurs stratigraphically highest and probably represents a quiet-water, very shallow, nearshore, marine environment. Although protected from strong wave and current activity, the water mass was occasionally turbid.

Species diversity of ostracodes is high both at the base of the Florena Shale, which was deposited in the most offshore position, and again at the top of the lower part of the Florena Shale, which was deposited nearer to the shore. In contrast to diversities of assemblages of ostracodes from similar environments in other stratigraphic units, the K. texana assemblage has an anomalously high diversity. This is due in part to time averaging of adjacent ostracode assemblages and a strong taphonomic overprint.

The ecdysial style of Flexicalymene meeki (Foerste) from the Upper Ordovician of the Cincinnati arch (Ohio) is best characterized by a spectrum of configurations. Recurring patterns of displaced tergites and points of disarticulation indicate differential susceptibility of the exoskeleton to disarticulation during ecdysis. Specimens identified as exuviae are characterized by one or more of the following: thoracic segments displaced (unevenly spaced, disarticulated or telescoped); pygidia and/or cephala rotated away from the sagittal line; cephalon sharply bent ventrally at first thoracic segment; librigenae separated or folded ventrally along facial sutures; “extra” tergites (exuvia) superposed on the new exoskeleton; and missing elements, especially librigenae and hypostomae. The range of exuvial configurations suggests a variety of ecdysial behavior in this trilobite.

The functional interpretation of Drepanosaurus unguicaudatus, an Upper Triassic lepidosaurian from the Italian Alps, is given here. The peculiar anatomical structure of the post-cranial skeleton would point to a burrowing animal.

Ontogenies of three trilobites from the Garden City Formation (Tremadocian to early Arenigian; equivalent to Ibexian) are described: Tesselacauda depressa (Pilekiidae), Rossaspis pliomeris (Protopliomeropsinae), and Protopliomerella contracta (Cybelopsinae).

Comparison of both larval and adult features of the described trilobites with those of cheirurids and encrinurids suggests that three lineages of the Cheirurina existed during the Early and Middle Ordovician. Members of the first lineage show the following hierarchical relationships; (Tesselacauda depressa (Cheirurinae (Acanthoparyphinae (two separate Sphaerexochinae groups)))). Within the second lineage, the following internested relationships of its members are recognized; (Protopliomeropsinae (“early” cybelines (“advanced” cybelines and Encrinurinae))). The Cybelopsinae constitute the third lineage that is considered as an immediate outgroup to the above two lineages. Pattern of nested distribution of synapomorphies within all these lineages reveals that the two pliomerid subfamilies (Protopliomeropsinae and Cybelopsinae) do not share a recent common ancestor, suggesting that the Pliomeridae is a paraphyletic group.

Foliomena folium (Barrande) and other very small, thin-shelled brachiopods from the Pyle Mountain Argillite in Aroostook County, Maine, provide the only record of the presence of the Foliomena fauna in North America. Associated fossils include numerous small trilobites and a few specimens of other groups. An Ashgill age is established by the presence of graptolites of the Climacograptus spiniferous Zone in the underlying Winterville Formation.

Most of the 190 specimens are small strophomenaceans and plectambonitaceans. One of the most numerous is the christianiid Nubialba forbesi n. gen. and sp. that has ribs and elaborately developed internal features. In the absence of evidence to contradict previous interpretations that the Foliomena fauna records cold-water environments, the presence of one or more deep basins along the southeastern margin of the trans-equatorial North American paleoplate occupied by cool peri-Gondwanan waters during a short segment of Ashgill time is implied.

Three new species of Hippocardia, H. ancora, H. pala, and H. cucullata, are described. Hippocardia ancora and H. pala occur together in the Lazy Bend Formation (Desmoinesian) of Texas. Hippocardia cucullata occurs in the Imo Formation (Chesterian) of Arkansas.

A thalattosaur taxon, Concavispina biseridens, was recently named and briefly described. It is described here in detail and compared with other thalattosaurs, especially Xinpusaurus. Concavispina is characterized by a long skull, measuring approximately half the length of presacral portion of the vertebral column, two rows of blunt teeth on the anterior part of the maxilla, and neural spines that have convex anterior or posterior margins and V-shaped notches in their dorsal margins. Concavispina differs from all thalattosaurs except Xinpusaurus in that the anterior end of the maxilla is curved dorsally, less than five cervical vertebrae are present, and the proximal end of the humerus is wider than the distal end. Phylogenetic analysis of 40 characters suggests that Miodentosaurus occupies a basal position within Askeptosauridea, Paralonectes is the basalmost member of Thalattosauridea, Concavispina may form a clade with Xinpusaurus, and Chinese thalattosaurs do not have a close relationship with eastern Pacific forms as suggested by previous studies. Concavispina may have been similar to Xinpusaurus in overall locomotor style, but probably had a poorer swimming ability. Concavispina likely differed from Xinpusaurus in diet, for example by depending on softer food.

The naticid gastropod predator–prey system has been cited as a possible example of coevolution. Previous work indicated that Miocene bivalves from the Chesapeake Group responded to naticid drilling with a predation-avoidance strategy of gradual thickness increase over evolutionary time. The present study examined whether the predators, Euspira heros (Say) and Neverita duplicata (Say), coevolved by increasing their efficiency in response to prey adaptation.

Neither predator showed significant trends in most characters thought to affect predator efficiency, including measures of globosity and aperture size relative to shell height. Stasis occurred for all such characters except Euspira aperture height, which showed a statistically significant decrease of 9 percent through the section. Morphologic trends occurred in two additional characters, shell thickness relative to height, and shell height. Euspira increased in thickness by 63 percent through the section; Neverita decreased in thickness by 37 percent (through slightly less section) and simultaneously increased mean height by 60 percent.

The size increase exhibited by Neverita could be interpreted as a coevolutionary response to increased prey defenses. Naticids are subject to predation by other naticids, however; the trends in size and thickness may be viewed instead as an evolutionary strategy to escape naticid predation, including cannibalism. Although the possibility of coevolution is difficult to eliminate, Chesapeake Group naticids appear to have evolve more in response to their own predators than to evolution of their prey.