The Pennsylvanian ammonoids Gastrioceras magoffinense n. sp., Maximites nassichuki n. sp., Dimorphoceratoides adamsi n. sp., Bisatoceras? sp., Phaneroceras chesnuti n. sp., and Christioceratidae gen. indet. occur in the Magoffin Member of the Four Corners Formation in eastern Kentucky. The interval represented by the Magoffin ammonoid fauna should be known as the Gastrioceras magoffinense Assemblage Zone. This overlies the well-known Diaboloceras neumeieri Zone, represented in the Kendrick Shale Member of the Hyden Formation in eastern Kentucky. The Gastrioceras magoffinense Zone correlates to the Diaboloceras varicostatum–Winslowoceras henbesti Zone in the Winslow Member of the Atoka Formation in northwestern Arkansas. Ammonoids and associated conodonts, including Declinognathodus marginodosus and its descendant D. donetzianus, indicate an early Atokan age corresponding to the basal Bolsovian (basal Westphalian C) Substage in western Europe and the Bashkirian–Moscovian Stage boundary interval in eastern Europe and the South Urals.

The Middle Devonian (Givetian) microconchid tubeworm species known as Spirorbis angulatus Hall, 1861 is redescribed here on the basis of a new collection from the Traverse Group of Michigan and Hamilton Group of Ohio and New York, U.S.A. Its general characteristics and ornamentation indicate it belongs to the genus Palaeoconchus Vinn, 2006. Because the original specimens on which the species was erected are lost, a neotype is here designated for a specimen from the same area (Erie County, New York) and stratigraphic interval (Hamilton Group, Givetian) as the original specimens described by Hall (1861). The new specimens of Palaeoconchus angulatus (Hall) show that the species is characterized by a spectrum of morphological variability, possibly ranging from a nearly smooth tube, though weakly ornamented, to one distinctly tuberculated on which thicker nodes and thin spines may occur together. Assemblages of microconchids from particular stratigraphic divisions are characterized by a dominance of small (up to 1.5 mm in diameter, probably juvenile) individuals, while larger individuals (>2 mm) are rare. This suggests that the populations may have experienced occasional mass mortalities. Although substrate (in this case brachiopod shells and rugosan coral thecae) overturning and an increase in sedimentation rate are possible factors, an episodic anoxia/dysoxia of the bottom waters seems likely as it is known that the host dark shales record such occasional oxygen deficiency.

A large collection of macrurous decapod crustaceans is recorded from the middle–late Anisian (Middle Triassic) Guanling Formation in Yunnan Province, China. A remarkable assemblage of over 20,000 vertebrate, invertebrate, and plant fossils collectively referred to as the Luoping Biota has been collected from quarries in the vicinity of the city of Luoping. Among these, arthropods including the decapods are the most common element although articulated fish and reptiles are also common. The decapods represent new taxa, including Koryncheiros luopingensis n. gen. n. sp. within Clytiopsidae, a newly elevated family within Erymoidea; Tridactylastacus sinensis n. gen. n. sp. within Glypheidae; and Yunnanopalinura schrami n. gen. n. sp. within Palinuridae. A single specimen has been referred to Palinuridae sp. Koryncheiros luopingensis exhibits a unique cheliped architecture and the second through fourth chelipeds are subchelate, an extremely rare configuration. Tridactylastacus sinensis also exhibits subchelate closures of pereiopods 2–4, but it bears a distinctive subchelate first pereiopod with an intercalated spine between the fingers on the distal margin of the propodus. Yunnanopalinura schrami represents the oldest occurrence of Palinuridae and Achelata. Collectively, these expand our knowledge of Chinese decapods significantly in that only six species of fossil decapods have been described previously from the country.

Protichnites eremita from the Cambrian Elk Mound Group of Wisconsin is reinterpreted based on new material and trackway experiments. Two new forms of P. eremita suggest that the discrete medial imprints of these traces could be produced by the segmented postabdomen of euthycarcinoids from the same deposit. Form 1 could have been produced by a pair of euthycarcinoids traveling together, like in limulid amplexus, where both individuals made imprints with their postabdomens. In this scenario, if one individual held its postabdomen to the left side, it is possible to produce left-handed shingling in trackways and angled segmentation of each medial imprint. Form 2 could have been produced by a single animal traveling in arcing or tightly looping paths. Experimentally-produced medial imprints yield morphologies that are consistent with both trackway forms. Thus, it seems more likely that P. eremita was produced directly by the animal's body (alone or paired) rather than by employing hermit-like behavior.

For many years the earliest record of the class Crinoidea was a single late Tremadocian genus. In the past decade, five crinoid genera were described from the early and middle Tremadocian, near the base of the Ordovician. Together these six genera represent a diverse assemblage with all but one expressing existing subclass apomorphies. Two of the recently described genera were initially assigned to their own order (plesion) Protocrinoida but not to a subclass. Here they are placed in the camerates based on apomorphies of the tegmen complex. Protocrinoids exhibit plesiomorphies unlike typical camerates. Two genera group with cladids, one expressing dendrocrinine apomorphies and the other cyathocrinine. One genus is placed within disparids, with iocrinid apomorphies.

Based on its ancient age and trait mosaic, the protocrinoid Titanocrinus is designated as outgroup in a phylogenetic analysis using all other Early Ordovician and select Middle Ordovician taxa as an ingroup. Character compilation and phylogenetic analysis posit early class-level plesiomorphies inherited from an unknown ancestry but lost during subsequent crinoid evolution. Class-level apomorphies also emerge, some of which were subsequently lost and others retained. Results are generally robust and consistent with earlier subdivisions of the class, but supporting lower rank reorganizations. Strong support for the camerate branch low in the crinoid tree mirrors findings of earlier workers. Cladids branch from a series of intermediate nodes and disparids nest highest. Branching of disparids from cladids could be homoplastic.

Maennilia estonica Rozhnov and Jefferies was first described as a stem-chordate but restudy shows it is an unusually large homoiostelean echinoderm. Its feeding structure, an erect ambulacrum, extending exothecally from the peristomial frame plates, bears a large internal tunnel that opens directly into the body cavity. This type of feeding appendage is now recognized to be unique to homoiosteles. It bears no evidence for water vascular system impressions adjacent to its food groove. The theca has poorly developed marginal plates and a narrow rim that, in contrast to some other homoiosteles, does not extend over either lower or upper thecal face. Maennilia appears to have inhabited the deeper portions of a near-shore environment in limey muds adjacent to a linear zone of bryozoan and microbial bioherms.

A total of 17 species of cladid crinoids are documented from the late Kinderhookian Meadville Shale Member of the Cuyahoga Formation of northeastern Ohio, the most diverse assemblage of Kinderhookian-age cladids known in North America. One new genus, six new species, and seven new combinations are reported. New taxa include Cuyahogacrinus lodiensis new genus and species, and the new species Cyathocrinites simplex, Atelestocrinus meszarosi, Goniocrinus sceletus, Aphelecrinus gracilis, and Lebetocrinus ohioensis. New combinations include Logocrinus warreni (Laudon et al., 1952), Histocrinus aegina (Hall, 1863), Paracosmetocrinus richfieldensis (Worthen, 1882), P. corycia (Hall, 1863), Acylocrinus lyriope (Hall, 1863), Linocrinus merope (Hall, 1863), and L. paternus (Hall, 1863). Remaining taxa include Cyathocrinites lamellosus (White, 1863) and Ascetocrinus whitei (Hall, 1861), both of which also occur in the Osagean Burlington Limestone, and the endemic species Cosmetocrinus crineus (Hall, 1863) and Pachylocrinus subtortuosus (Hall, 1863).

Collectively, the cosmopolitan genera and species of cladids show a greater overall affinity with Osagean cladid faunas than with other Kinderhookian cladid faunas. However, this is true for other Kinderhookian cladid faunas as well that individually have more taxa in common with Osagean faunas than other Kinderhookian faunas. This suggests a greater degree of endemism and local speciation during the Kinderhookian as a prelude to the rapid radiation of cladids, and other crinoids, during the Osagean.

Crinoids were first reported from the Cuyahoga Formation in northeastern Ohio by James Hall in 1863. However, these crinoids have not been re-examined in detail since the late nineteenth century. With the restudy of classical and more recent collections, ten (nine camerate and one disparid) species-level taxa are recognized from the late Kinderhookian Meadville Shale Member, Cuyahoga Formation, including the camerates Amphoracrinus viminalis (Hall, 1863); Aorocrinus helice Hall, 1863; Aorocrinus meyeri n. sp.; Aryballocrinus martini n. sp.; Cusacrinus daphne (Hall, 1863); Platycrinites s.l. contritus (Hall, 1863); Platycrinites s.l. graphicus (Hall, 1863); Platycrinites s.l. lodensis (Hall and Whitfield, 1875); and Platycrinites s.l. burkei n. sp. In addition, Halysiocrinus sp. is the first disparid reported from this fauna. Platycrinites s.l. bedfordensis (Hall and Whitfield, 1875) is designated a nomen dubium. Growth is evaluated for Aorocrinus helice and Cusacrinus daphne, which had contrasting development. The growth of the Aorocrinus helice calyx was largely not allometric but that of the primaxil plate was, suggesting the arms may have grown allometrically. In contrast, much of the calyx of Cusacrinus daphne displayed allometric growth.

A new species of the staphylinid subfamily Oxytelinae is described and figured from a series of well-preserved compression fossils of the Yixian Formation (Early Cretaceous), Beipiao City, Liaoning Province, northeastern China. The species is placed in the recent genus Anotylus Thomson, 1859 based on typical morphological features for the genus as well as secondary sexual characters. The strong projection of the anterior pronotal angles is a feature also possessed by males of several recent Neotropical taxa in the genus. This is the earliest fossil rove beetle with clearly demonstrable sexual dimorphism.

Four new species of colonial corals, one previously described coral, and two other unidentified species of coral have been recovered from the Baird Formation in the Klamath Mountains of northwestern California. The newly erected species are Heritschioides armstrongi n. sp., Pararachnastraea klamathensis n. sp., P. watkinsi n. sp., and P. kabyaiensis n. sp. These corals are associated with the fusulinids Millerella marblensis Thompson, 1944, Paramillerella Thompson, 1951, and Pseudostaffella Thompson, 1942, emend Groves, 1984, suggesting an early Atokan (Bashkirian) age. Both the coral and foraminiferal faunas bear a resemblance to those of similar age in the Brooks Range, Alaska, which could suggest geographic proximity between the two terranes at that time. These corals also represent the earliest known occurrence of the Family Durhamididae.

Ascidian spicules are reported for the first time from the upper Eocene (Paleogene) biosiliceous marls and mudstones of the Blanche Point Formation in the St. Vincent Basin, southeastern Australia. The spicules that belong to the family Polycitoridae are identified as a Recent species Cystodytes cf. dellechiajei, and Cystodytes sp. and spicules of the family Didemnidae are indentified as representing genera Lissoclinum, Didemnum, and Polysyncraton. Five other different morphological spicule types which can be classified only at the family level also belong to the Didemnidae. This study demonstrates that ascidians had a very wide distribution by the late Eocene and that ascidian fauna was already of a modern character.

Biogenic structures, herein interpreted as coprolites, were recorded in the ?upper Paleocene–Eocene Las Flores Formation, southeast Argentina. The coprolite origin is supported by several features, such as recurrent extrusive external morphology, longitudinal wrinkles, flattening of the ventral side, concentric and radial cracks, cryptocrystalline groundmass, and a phosphatic composition. A detailed comparative study with modern fecal masses, based on morphology, surface texture, micromorphology, mineralogical and chemical composition, suggest a crocodylian as the most probable producer, an interpretation also supported by the Patagonian paleontological record. This discovery, the first record on coprolites from Central Patagonia, provides new paleoenvironmental and paleoecological information for the studied successions.

Four distinct fossil turtle assemblages (Chelonia) are recognized from the Panama Canal Basin. The oldest, from the late Eocene–early Oligocene Gatuncillo Formation, is dominated by podocnemidid pleurodires. The early Miocene Culebra Formation includes both podocnemidids and trionychids. The early to middle Miocene Cucaracha Formation includes taxa classified in Geoemydidae (including Rhinoclemmys panamaensis n. sp.), Kinosternidae (represented by Staurotypus moschus n. sp.), large testudinids, trionychids, and podocnemidids, and finally, the late Miocene Gatun Formation records cheloniid sea turtles. These fossils include the oldest known representatives of Rhinoclemmys, the oldest record of kinosternids in Central America with a more extensive southern paleodistribution for Staurotypus and staurotypines in general, early occurrences of giant tortoises in the Neotropics, the oldest occurrence of soft-shell turtles in the tropics, the oldest late Eocene–early Oligocene Neotropical occurrences of podocnemidids. The Panamanian fossil turtles represent clades that are primarily endemic to North America, showing their very early arrival into the Neotropics prior to the complete emergence of the Isthmus of Panama, as well as their first contact with Caribbean-South American pleurodires by the early Miocene.

Numerous exuviae of three Dechenella species (D. givetensis, D. ziegleri and D. calxensis) from the Middle Devonian (Givetian) of NE France (Ardenne Massif) provide the opportunity to identify the evolutionary modifications of ontogeny of the three Dechenella species and to elaborate a conceptual framework of developmental shape changes. First we used biometric and morphometric approaches to characterize shape modifications. Then we computed ontogenetic trajectories by multivariate regression of geometric shape variables on centroid size in order to compare them. Finally, we compared parallelism between trajectories and rates of development relative to size. These analyses demonstrate a significant difference in the cranidial developmental trajectories of D. givetensis and D. ziegleri indicating an allometric repatterning. However, pygidia of these species share the same allometric pattern with a distinct developmental rate suggesting that heterochrony could be a partial explanation for the body shape evolution. Pygidial ontogeny of D. calxensis corresponds to an allometric repatterning with respect to both other species. This work illustrates the complexity of evolutionary modifications of ontogeny constituting an important process in morphological novelties.