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.

Three gogiid eocrinoids, numbering in the thousands of specimens, are well known from the lower Cambrian (Stage 4) Balang Formation (Guizhoueocrinus yui) and basal middle Cambrian (Stage 5) Kaili Formation (Kaili Biota) (Sinoeocrinus lui and Globoeocrinus globulus) that resided on the Yangtze-South China Plate (modern Guizhou Province, China). In each species a complete ontogenetic sequence, using thecal height (TH) as a scale, juvenile stage (early, middle, and late substages), mature stage (early, middle, and late substages), and a gerontic stage can be identified. Sutural pores appeared in an orderly sequence; below the ambulacrals, above the stalk and generally over the theca, in that order. In younger species their emplacement and growth was commonly precocious relative to G. yui. Also, their shape ranges from circular to oval to triangular in a single growth sequence, after the establishment of the 2-1-2 pattern; brachioles were added in series of five and were also precocious in time of occurrence in younger species. Thecae in younger species tend to retain juvenile aspects relative to G. yui. All of these species lived in outer shelf settings in fine-grained, organic-rich siliciclastics.

Thirty species of Cancellariidae in 11 genera from the Miocene Gatun Formation in the Panama Canal area, Caribbean Panama, are discussed including two species not represented by specimens suitable for formal description. The following 11 species are described as new: Cancellaria harzhauseri n. sp., Cancellaria mixta n. sp., Bivetiella dilatata n. sp., Euclia alacertata n. sp., Pyruclia tweedledum n. sp., Pyruclia tweedledee n. sp., Massyla toulai n. sp., Aphera aphrodite n. sp., Axelella cativa n. sp., Agatrix agathe n. sp., Ventrilia coatesi n. sp. This assemblage of cancellariids is very diverse and highly endemic, with 18 (60 percent) species found only in the Miocene Gatun Formation. These assemblages all lie within the Gatunian Neogene Paciphile Molluscan Unit 1 (GNPMU1).

A stenolaemate bryozoan fauna containing 20 species belonging to 18 genera is described from the Las Plantas and Las Aguaditas formations (Upper Ordovician, Sandbian) in San Juan Province, Precordillera of Western Argentina. One genus with one species is new: Argentinodictya lenticulata n. gen. n. sp. (Cryptostomata, Ptilodictyina). Four species are new: one trepostome Parvohallopora parvula n. sp., two cryptostomes Trigonodictya parvula n. sp. and Ptilodictya intermedia n. sp., and phyloporinine Chasmatopora rossae n. sp. The bryozoan assemblage of the Las Plantas Formation is more diverse than that of the Las Aguaditas Formation. Fourteen species are restricted to the Las Plantas Formation, five species occur in both formations, and one species is restricted to the Las Aguaditas Formation. Erect growth forms are dominant in the studied fauna. The majority of bryozoan taxa display palaeobiogeographic relations to Sandbian–Katian deposits of North America, with two species also known from the Katian of Europe.

A fossil spider from the Cretaceous Jinju Formation of Korea is redescribed as Korearachne jinju, n. gen. n. sp. Previous description of this specimen, the only known fossil spider from Korea, was inadequate, and here we present a more detailed interpretation and illustration of the specimen. The fossil spider is preserved alongside juvenile albuiform fish, Diptera and possible crustaceans, which suggests a mass mortality event. Familial identification of the spider is impossible, but it probably belongs to a guild of wandering spiders, possibly lycosoids.

The ecological segregation of large, multicellular eukaryotes in the Ediacaran in response to competitive feeding results in the evolution of novel morphological adaptations such as sturdy stems to elevate above lower-tier feeding guilds. Culmofrons plumosa n. gen. n. sp. lived attached to the ocean floor and probably fed osmotrophically from dissolved organic nutrients in the water column. Competition for nutrients with specialized lower-tiered organisms resulted in the evolution of a specialized non-feeding structure, drastically expanding the functional morphospace available to Ediacaran rangeomorphs. The first appearance of a cylindrical macroscopic stem in C. plumosa in the Briscal Formation of the Mistaken Point Ecological Reserve marks a significant departure from the modular repetitive branching typical of the Rangeomorpha, and exemplifies the importance of nutrient acquisition in early ecosystem engineering.

The Visean–Serpukhovian boundary is not yet defined by a Global Stratotype Section and Point (GSSP) but it is recognizable operationally by the appearance of the conodont Lochriea ziegleri in the L. nodosa–L. ziegleri chronocline. Foraminiferal successions across this boundary in the type area of the Serpukhovian Stage (Moscow Basin, Russia), elsewhere in Russia and in the central United States suggest that the appearances of Asteroarchaediscus postrugosus, Janischewskina delicata, Eolasiodiscus donbassicus, and specimens controversially referred to “Millerella tortula” are reliable, auxiliary indices to the base of the Serpukhovian. In southern Guizhou Province, China, Visean–Serpukhovian rock sequences from slope and platform settings have yielded rich associations of conodonts and foraminifers, respectively. The Nashui section is a leading candidate for the Serpukhovian GSSP because its slope deposits contain an uninterrupted record of conodont occurrences including the L. nodosa–L. ziegleri transition. Foraminifers recovered from the Nashui section are comparatively rare and include none of the basal Serpukhovian indices. In contrast, the nearby Yashui section represents a platform interior setting in which foraminifers flourished and conodonts were nearly absent. The base of the Serpukhovian at Yashui is marked approximately by the appearance of “tortula-like” specimens. Although it is not possible to correlate biostratigraphically between the Nashui and Yashui sections, the occurrence of “tortula-like” specimens at the Yashui section allows correlation with the mid-Venevian Substage of the Moscow Basin at a level coinciding with the appearance of L. ziegleri. Together, the slope and platform sections comprise an informative biostratigraphic reference area for micropaleontologic characterization of the Visean–Serpukhovian boundary in southern Guizhou.

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.

Nine agnostoid species from late Cambrian (Paibian: Steptoean) boulders from the Cow Head Group in western Newfoundland fall into three biostratigraphically distinct faunas. The Glyptagnostus reticulatus Fauna contains only the eponymous species and correlates with the lower part of the Paibian and the basal Steptoean of North America. The “Innitagnostus” inexpectans Fauna is more diverse and likely correlates into part of the lower Steptoean Aphelaspis Zone of western North America. The youngest fauna, the Acmarhachis kindlei n. sp. Fauna, also includes species of Homagnostus and Pseudagnostus, as well as a second new species of Acmarhachis, A. whittingtoni. It probably correlates with the Dunderbergia Zone (mid-Pabian and mid-Steptoean) of the western United States. The Laurentian species Acmarhachis typicalis Resser (1938) and A. acuta (Kobayashi, 1938) are evaluated from restudy of type material, and types of “Innitagnostus” inexpectans (Kobayashi, 1938) from British Columbia are also reillustrated.

Little is known about the habit and spatial distribution of Early Permian tropical vegetation, a sharp contrast with the Pennsylvanian from which many in-situ “T0” assemblages are known. Even less is known about the potential interaction of plants and vertebrates. Here we report the discovery of a small stand of 34 probable Supaia White plants from the Abo Formation of New Mexico. The plants were growing on a mudflat, subject to periodic flooding and exposure. The same mudflat hosts trackways of vertebrates that appear to have walked around or between the Supaia plants. The stems are preserved as molds, and vary from 20 mm to 70 mm in diameter, averaging 42.4 mm, indicating heights of approximately 2.5–4 m. The plants, which may be described as small trees given their estimated height, are as close as 110 mm to their nearest neighbor and average nearly 300 mm apart. A series of lines or filled fissures, which we interpret as roots, radiates from the base of each stem. Leaves of Supaia thinfeldioides White are the only foliage found in association with these stems, on bedding planes above and at the base of the lowest expression of the stem molds. Associated vertebrate trackways either congregate around some of the stems or wend their way between the stems and include those of a single large temnospondyl amphibian (Limnopus Marsh) and many of small predatory parareptiles (Dromopus Marsh). This study demonstrates that S. thinfeldiodes were small-statured, weedy, opportunistic plants. It also shows that contemporaneous vertebrates prowled such environments, presumably either for food, shelter, or both given detectable pace and path.

The Hanneh Member (Cambrian Stage 5) of the Burj Formation and the Umm Ishrin Formation of Jordan represent a transgressive-regressive succession that contains twenty-eight ichnotaxa, including vertical burrows (Arenicolites isp., Diplocraterion isp., Gyrolithes polonicus, Rosselia isp., Skolithos linearis, escape trace fossils), horizontal simple burrows and trails (Archaeonassa fossulata, Gordia marina, Helminthoidichnites tenuis, Palaeophycus tubularis, Planolites beverleyensis, P. montanus), plug-shaped burrows (Bergaueria sucta), horizontal branched burrows (Asterosoma isp., Phycodes isp., Treptichnus cf. T. pedum), bilobate structures (various ichnospecies of Cruziana and Rusophycus), and trackways and scratch marks (Diplichnites isp., Dimorphichnus cf. D. obliquus, Monomorphichnus isp.). Eleven trace-fossil assemblages are identified. The Arenicolites isp. and Diplocraterion isp. assemblages occur in transgressive tidal dunes and bars whereas the Rosselia isp. assemblage characterizes areas between tidal dunes. The Cruziana salomonis assemblage reflects a wide variety of environmental settings including channels within tidal-bar complexes, bottomsets of tidal dunes, and interdune areas. The Gordia marina assemblage is present between dune patches. The Gyrolithes polonicus assemblage penetrates into firmground mudstone below the maximum flooding surface. The Bergaueria sucta, Archaeonassa fossulata, Rusophycus aegypticus and Cruziana problematica assemblages occur in different subenvironments of the progradational delta. Cruziana salomonis and Rusophycus burjensis, originally considered indicative of an early Cambrian age, are actually middle Cambrian in their type locality. Occurrences of Cruziana jordanica and Rusophycus aegypticus provide evidence that these ichnospecies are of the same age in Jordan and may co-exist in terms of stratigraphic distribution with C. salomonis and R. burjensis.

An early Cambrian ichnofauna consisting of Helminthoidichnites tenuis, Helminthopsis tenuis, Multina isp., Oldhamia alata, and Pilichnus cf. dichotomus is documented from shallow-marine deposits ranging from the upper offshore to the offshore transition in the Puncoviscana Formation of northwest Argentina. Although the ichnogenus Oldhamia is more common in Cambrian deep-marine environments, this occurrence provides further evidence that it is also present in shallow-marine environments. The burrow network Multina (senior synonym of Olenichnus) is preserved at the base of tempestites, representing the activity of post-storm colonizers. A drowning surface separating offshore-transition deposits below from upper-offshore deposits above contains widespread evidence of trace fossils in direct association with matgrounds. The undermat miners Oldhamia alata and Pilichnus cf. P. dichotomus occur on this surface, revealing exploitation of organic matter in the biomat. Low sediment rate during drowning and paucity of bioturbation by sediment bulldozers may have promoted the establishment of the matground. In comparison with the simpler animal-matground interactions characteristic of the Ediacaran, the combination of Cambrian evolutionary innovations and the presence of microbial mats promoted more sophisticated interactions. Complex feeding trace fossils revealing that systematic undermat mining, as displayed by Oldamia alata and Pilichnus cf. dichotomus, is a product of the Cambrian explosion.

Universal elemental homology (UEH) is used to establish homology of thecal plates and elements of the ambulacral system among clades of stemmed echinoderms by placing these structures into a testable hypothesis of homology. Here UEH is used to explore hypotheses of homology in blastoids, coronoids, Lysocystites, hemicosmitoids, and glyptocystitoids. This new approach to analyze homology is particularly powerful in understanding the nature of the thecal plates of blastoids and how they relate to other taxa in a common nomenclatural lexicon. In blastoids, deltoids are interpreted as oral plates that are homologues to oral plates of glyptocystitoids and hemicosmitoids whereas side plates are interpreted to be ambulacral floor plates. Thecal plates are homologous among blastoids, coronoids and Lysocystites but these morphologies cannot be reconciled with plate circlets of glyptocystitoids and hemicosmitoids. A phylogenetic analysis of these taxa presents the origin of blastoids as sister taxon of coronoids within a testable series of homologies.

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.

A brachiopod fauna of late Bathonian age recovered from the Kehailia Formation from Gebel Engabashi in northern Sinai consists of six species (two rhynchonellids and four terebratulids) referred to six genera, of which one genus and two species are new: Globirhynchia sphaerica (Cooper, 1989) new combination, Daghanirhynchia angulocostata Cooper, 1989, Ectyphoria sinaiensis new species, Cooperithyris circularis new genus and species, and new material: Avonothyris species A, and Ptyctothyris species A. The brachiopods described herein comprise a fauna located at the northern part of the Indo–African Faunal Realm within the Jurassic Ethiopian Province. They extend the geographic distribution of those taxa that show great affinity with the Jurassic brachiopod fauna of Saudi Arabia described by Cooper (1989). Differentiation of the endemic faunas that is so characteristic of many of these Ethiopian Province faunas is becoming more well-defined.

Tympanal ears in insects are important for both intraspecific communication and for the detection of nocturnal predators. Ears are thought, based on modern forms, to have originated independently multiple times within insects and can be found on multiple regions of the body. Here we describe and document the exceptionally well preserved tympanal ears found in crickets and katydids from the Eocene Green River Formation of Colorado, which are virtually identical to those seen in modern representatives of these groups. These specimens are among the best preserved insect ears in the fossil record and establish the presence of ears in two major clades of Orthoptera 50 million years ago. Also discussed and evaluated are previously described insect ears from the Mesozoic and the implications of the findings of the present study for studying the evolution of ears within insects.

Two new kirkocystid mitrate stylophorans (Echinodermata, Homalozoa) and a new possible solute (Echinodermata, Homalozoa) are described from the Early Ordovician of the western United States. The mitrates are among the earliest members of their clade to appear near the beginning of the Ordovician Radiation. Anatifopsis ninemilensis new species comes from the Ninemile Shale in central Nevada and the McKelligon Canyon Formation in west Texas. Anatifopsis fillmorensis new species comes from the middle Fillmore Formation in western Utah and a Ninemile Shale equivalent limestone bed in southern Nevada. The possible solute Drepanocystis dubius new genus new species from the lower Wah Wah Limestone in western Utah, shows unusual morphology with an elongate theca and a long arm shaped like a sickle.

Microscopic phosphatic scales are found in limestones and cherts from the 812–717 million year old Fifteenmile Group of the Yukon Territory. These enigmatic microfossils, which to date have not been identified in any other locality, display a diversity of intricate morphologies. Here we describe six new genera containing 17 new species of scale microfossils obtained from macerated limestone. We also revise existing taxa described originally from chert thin sections and now additionally freed from limestone by acid dissolution. New taxa described here are: Archaeoxybaphon serratacapacis n. sp., Archeoxybaphon serratapusilla n. sp., Paleoscutula inornata n. gen. n. sp., Paleoscutula serrata n. gen. n. sp., Paleoscutula convocationis n. gen n. sp., Hexacatillus allmonii n. gen. n. sp., Hexacatillus retetantillus n. sp., Quadrireticulum allisoniae n. gen. n. sp., Quadrireticulum palmaspinosum n. gen. n. sp., Circidentatus pistricis n. gen. n. sp., Circidentatus variodentatus n. gen. n. sp., Ospercapatera awramikii n. gen. n. sp., Circitorquis soccus n. gen. n. sp., Paleohexadictyon alexandrae n. sp., Paleomegasquama arctoa n. sp., Petasisquama petasus n. sp., and Thorakidictyon circireticulum n. gen. n. sp. Taxa described or amended here are Characodictyon skolopium Allison and Hilgert, 1986, Paleohexadictyon myriotrematum Allison and Hilgert, 1986, Archeoxybaphon polykeramoides (Allison and Hilgert, 1986) emend., Paleohexadictyon litosum (Allison and Hilgert, 1986) emend., and Thorakidictyon myriocanthum (Allison and Hilgert, 1986) n. comb. Many eukaryotic clades include species with surficial scales but none provides a close morphological analog to the Fifteenmile scales. Nonetheless, comparative and functional morphology suggest that the diversification of heavily armored and morphologically complex cell-coverings records a changing ecological landscape in Neoproterozoic seas.

The thickness ratios of shell whorls (=whorl breadth/shell diameter) in the ammonoids Damesites sugata (Forbes, 1845), Hypophylloceras subramosum (Shimizu, 1934), and Gaudryceras tenuiliratum Yabe, 1903 from Late Cretaceous outer shelf deposits in the Kotanbetsu area of northwestern Hokkaido, Japan, were examined in order to determine their mode of migration. The thickness ratios of D. sugata differ significantly with depth on the outer shelf environment but show no significant difference laterally at a similar depth. These results suggest that D. sugata did not frequently migrate to different depths on the outer shelf environment but tended to live and migrate laterally at a similar depth on the outer shelf. The thickness ratios of H. subramosum and G. tenuiliratum show no significant difference between different depths on the outer shelf environment or for lateral direction at a similar depth. This suggests that H. subramosum and G. tenuiliratum frequently migrated at different depths on the outer shelf environment and laterally at a similar depth. There is no difference in hatchling diameters in all the examined species at different depths on the outer shelf environment, suggesting that the thickness ratios became manifest after the post-hatchling stage due to limited migration, which would have been in a nektobenthic habitat. The various modes of migration in the study area are reconstructed in this study, suggesting diversified paleoecology of Late Cretaceous ammonoids.

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.