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Newly found fossils in the Conception and St. John's groups of the Bonavista Peninsula considerably extend the known geographic distribution of the Ediacaran fossils in Newfoundland. They occur in deepwater sediments and are preserved as epireliefs, forming census populations underneath volcanic ash layers throughout a more than 1 km thick turbiditic sequence. The exposed fossiliferous units comprise the Mistaken Point, Trepassey, Fermeuse, and Renews Head formations. The remains are tectonically deformed, with long axes of elliptical discs aligned parallel to cleavage strike; shortening of originally circular bedding surface features is on the order of 30–50% (averaging ∼35%).
The assemblage includes Aspidella, Blackbrookia, Bradgatia, Charnia, Charniodiscus, Fractofusus, Hiemalora, and Ivesheadia. These occur throughout the succession, with Aspidella being the most common genus, followed by Charnia and Charniodiscus. Four new taxa are described, with candelabra-like fossils with a Hiemalora-like base referred to Primocandelabrum hiemaloranum n. gen. and sp., bush-like fossils to Parviscopa bonavistensis n. gen. and sp., ladder-like fossils to Hadryniscala avalonica n. gen. and sp., and string-like fossils with basal disc to Hadrynichorde catalinensis n. gen. and sp. The remains also include dubiofossils. The stratigraphic ranges of some taxa on the Bonavista Peninsula are longer than previously reported from the Avalon Peninsula, with Fractofusus spindles present in the Trepassey Formation, Bradgatia, Charnia, Charniodiscus, and Ivesheadia reaching as high as the Fermeuse Formation, and Aspidella extending into the middle of the Renews Head Formation. The spindles in the Trepassey Formation are comparable to those found mainly in the stratigraphically older Briscal Formation on the Avalon Peninsula.
Radiolarians collected from five localities of the Baltalimani Formation in the Istanbul region are described in detail, and the local stratigraphic ranges and persistence of biostratigraphically important radiolarian species are documented. The spumellarian component is published for the first time, and four new species are described: Albaillella kayai n. sp., Ceratoikiscum jucundum n. sp., Meschedea akcetensis n. sp., and Stigmosphaerostylus istanbulensis n. sp. Two assemblages are recognized: the A. paradoxa and the A. sp. aff. A. undulata-A. deflandrei assemblage. The older A. paradoxa assemblage contains Traenosphaera sicarius, Pararchocyrtium serrensis, Cyrtisphaeractenium mendax, and common to abundant A. paradoxa and Popofskyellium. Albaillella paradoxa is not restricted to the older assemblage but is the only species of Albaillella present. The younger A. sp. aff. A. undulata-A. deflandrei assemblage contains either A. sp. aff. A. undulata or A. deflandrei. Albaillella indensis ambigua, A. kayai n. sp., and Kantollium sp. A occur exclusively in the A. sp. aff. A. undulata-A. deflandrei assemblage, but are rare and patchy in their occurrence. Distinctive taxa common to both assemblages are Archocyrtium lagabriellei, Pylentonema antiqua, C. avimexpectens, C. umbraculatum, C. jucundum n. sp., Trilonche palimbola, M. akcetensis n. sp., S. tortispina, Polyentactinia polygonia, P. aranea, and Cubaxonium? octaedrospongiosum. Many of the taxa present occur in middle and upper Tournasian sections from France, the central Pyrenees, and Germany and provide a solid basis for re-assessing the age of the Baltalimani Formation as middle to late Tournasian (Tn2–Tn3).
Iocrinus trentonensis Walcott, 1883 is characterized by the widest food grooves and the largest covering plates of any of the Walcott-Rust Quarry crinoids, which indicates that the animal captured relatively large food particles with large and widely separated tubefeet. Although iocrinids are generally considered as primitive disparids, their anal sac is unique. The holdfasts of I. trentonensis consist of distal stem coils that are tightly wrapped around the columns of other crinoids. The relatively long column of Ectenocrinus simplex (Hall, 1847) was attached to a wide range of shelly substrates by a small irregular and somewhat lobate holdfast. Ectenocrinids ate much smaller food items that were collected by smaller and more tightly packed tubefeet. The ontogeny of E. simplex illustrates the differences between the food gathering systems of conspecific crinoids from shallow and deep water habitats. The calceocrinid Calceocrinus barrandii Walcott, 1883 lived with its long stem forming a runner along the seafloor. The crown was movably hinged to the basal circlet and the stem. Moderately wide food grooves were probably present.
Multivariate morphometric analysis was applied for differentiation of closely related species and evaluation of intra- and interspecific variation in Manipora from the Selkirk Member, Red River Formation, in southern Manitoba. Seven morphological characters were quantified in transverse thin sections of 46 coralla and statistically tested for selecting effective characters in discriminating species. Cluster analysis was performed on a raw data matrix coordinated with 46 coralla by three selected characters. Two major clusters on the resulting dendrogram were regarded as morphospecies, following comparative examination of the coralla using serial sections. Cluster analyses were also conducted on principal component score matrices obtained from the raw data set coordinated with 46 coralla by all seven characters, and from an experimental data set including the 46 coralla plus two replicates of each and six of the characters. The results agree closely with the first cluster analysis, but discrimination of morphospecies was slightly degraded. The validity of two morphospecies recognized in the first cluster analysis was verified by discriminant analyses, descriptive statistics, and bivariate plots. The results show that tabularium area is the most meaningful character for distinguishing these morphospecies; ranges of variations of the other six characters overlap between morphospecies.
Another cluster analysis like the first was performed, but with the addition of 11 type specimens and reference coralla of Manipora species from the Upper Ordovician of southern and northern Manitoba and Texas. Based on this analysis, together with comparative examination of thin sections, the two morphospecies are identified as valid species: M. amicarumSinclair, 1955 and M. manitoba (Sokolov, 1955). Manipora magnaFlower, 1961 is considered to be a synonym of M. amicarum, while M. trapezoidalisFlower, 1961 and M. garsonensisCaramanica, 1992 are considered to be synonyms of M. manitoba, and the hypotypes of M. amicarum of Nelson (1963) are assigned to M. manitoba.
A small faunule of hypercalcified agelasiid demosponges has been recovered from outcrops of the Silurian Heceta Formation on Prince of Wales Island in southeastern Alaska. Included are abundant Girtyocoeliana epiporata (Rigby and Potter, 1986), of the Girtyocoeliidae Finks and Rigby, 2004; fragments of Alaskaspongiella laminosa n. gen. and sp., Polyplacospongia nodosa n. gen. and sp., and Monolaminospongia gigantia n. gen. and sp., of the Auriculospongiidae Termier and Termier, 1977, and Cladospongia alaskensis n. gen. and sp., Virgulaspongia uniforma n. gen. and sp., and Stipespongia laminata n. gen. and sp. of the Preperonidellidae Finks and Rigby, 2004. Also included are a few fossils of uncertain taxonomic placement, including Turbospongia biperforata n. gen. and sp., along with a small, chambered, tubular fragment and several porous tubular stems that may be additional poriferans. Some isolated octactine-based heteractinid spicules were also recovered from the etched residues.
The specimens of Gastrochaena cuneiformisSpengler, 1783, with Spengler-written labels at the Zoologisk Museum, Copenhagen, did not come from Spengler's type locality in the Nicobar Islands, and may instead be syntypes of Chemnitz's (1788) West Indies “Pholas hians”. The identity of Gastrochaena cuneiformis as a senior synonym of Gastrochaena gigantea (Deshayes, 1830) is established on the basis of Spengler's original descriptions and illustrations, and by examination of specimens from the type locality. A neotype for G. cuneiformis is designated and illustrated, and its genus is revised to exclude RocellariaBlainville, 1829, and Lamychaena Freneix inFreneix and Roman, 1979. GastrochaenaSpengler, 1783 is the most plesiomorphic of these three genera, as shown by its simple boring, short siphons, and diffuse, poorly differentiated anterior pedal muscles. Rocellaria evolved from a close common ancestor with Gastrochaena, and is characterized by a ventral shift and fusion of the posteroventral pallial sinus with the posteroventral pallial band, low, irregular posterior commarginal lamellae, and well defined anterior pedal retractor muscles generally supported by myophores. Lamychaena evolved from Rocellaria during the Oligocene, extending its ctenidia far posterior into the siphonal part of the boring, and, in some species, uniting its anterior pedal retractor and protractor muscles as they approach the byssus apparatus.
Two Permian fusulinid faunas, including nine species belonging to six genera, from the northern Tengchong Block, Southwest China, are studied and compared with the coeval fusulinid faunas from other blocks with Gondwana-affinity and South China. In the Kongshuhe section, the fauna is dominated by Eoparafusulina in the lower part of the Dadongchang Formation and possibly suggests an age of Sakmarian, while in the Shanmutang section, the fauna from the middle of the Dadongchang Formation mainly consists of Chusenella mingguangensis n. sp. and Monodiexodina gigas n. sp., indicating a Wordian to Capitanian age. Study has also demonstrated that fusulinid faunas from the Tengchong Block shared similar features with the contemporary faunas from the Baoshan Block and Sibumasu Block in the low generic and specific diversities and the absence of the taxa commonly found in Cathaysia Tethys areas, such as the Pseudoschwagerinidae, Verbeekinidae, and Neoschwagerinidae. However, visible differences in species composition still exist between the faunas of the Tengchong Block and those of the other two blocks, revealing an apparent regional feature in the faunas of the Tengchong Block.
Most species of the middle and late Hettangian psiloceratid genus Sunrisites are endemic to the eastern Pacific, where they are common members of ammonoid assemblages. The Taseko Lakes map area in British Columbia yields diverse and well-preserved Sunrisites faunas which are formally described here for the first time. Three new species are recognized, S. brimblecombei, S. chilcotinensis, and S. senililevis. The new species require an extension of the morphological range of the genus to include forms that become moderately involute at large shell diameters. Signs of sexual dimorphism are apparent within all three new species of Sunrisites. This work extends the stratigraphic range of Sunrisites to include the latest Hettangian Rursicostatum Zone in North America. The distribution of Sunrisites suggests that the Hispanic Corridor, which linked the western Tethyan Ocean and the eastern Pacific, may have been open during the Hettangian. Furthermore, occurrences of the genus constrain the Hettangian position of several allochthonous terranes to the northeastern Pacific.
Two new Mesozoic gastropod species, provisionally attributed to the minute (height < 5 mm) coiled neomphalid genus Retiskenea?, are described from three geographically isolated, Early Cretaceous, hydrocarbon seep-carbonate sites at Wilbur Springs, Rice Valley, and Cold Fork of Cottonwood Creek, northern California (USA). A fourth paleo-seep locality at Paskenta, of probable Upper Jurassic age, also yielded a single specimen of a morphologically similar microgastropod that may be a neomphalid with affinities to the Lower Cretaceous specimens described herein. The limestone lenses are ∼2–260 m in length, ∼1–5 m in diameter, and surrounded by forearc siliciclastics of bathyal turbidites or sedimentary serpentinites in the Upper Jurassic to Lower Cretaceous (Tithonian–Albian) Great Valley Group and its equivalents. The Lower Cretaceous microgastropods are tentatively placed in Retiskenea? based on similar shell characters: size, globose shape, inflated reticulate protoconch, number and distinct inflation of the body whorls, and fine, prosocline sculpture of the final body whorl. The fossils occur in carbonate microbialites that formed in seafloor sediments during archaeal anaerobic oxidation of methane in the zone of bacterial sulfate reduction, associated with H2S- and CH4-rich fluid seepage. The California Retiskenea? fossils commonly are found in gregarious clusters, or closely affiliated with thin worm tubes or, in one case, a larger gastropod.
These Mesozoic records increase the total known species attributable to this cold-seep endemic genus from two to four. Its spatial and temporal distribution thus may have spanned ∼9,000 km around the Pacific Rim from at least ∼133 m.y. to the present in 10 subduction-related seep sites from California (possibly Upper Jurassic–Lower Cretaceous), Washington (middle Eocene–Upper Oligocene), and modern offshore Oregon, the eastern Aleutians, and the Japan Trench. If the generic placement of these microgastropod fossils is correct, the California records are the oldest-known occurrences of Retiskenea, consistent with an estimated minimum Mesozoic origin for the ‘hot vent’ Neomphalidae, as inferred from molecular analyses published on other living members of the family.
Fossil carnivorans are described from earliest Eocene localities in the Clarks Fork and southern Bighorn basins of Wyoming. Three new species, Miacis rosei, Uintacyon gingerichi, and Vassacyon bowni, collected from the base of the Wasatchian North American Land Mammal Age (Wa-0), are the smallest and possibly most basal members of their respective genera, and increase from one to four the number of miacids known from this faunal zone. An upper dentition of Miacis deutschi from slightly younger (Wa-2) deposits is also described. Previously known only from lower teeth and a single M1, the specimen of M. deutschi includes the left P3-M2, alveoli for the canine, first two premolars and the last molar, as well as most of the maxilla. The new material helps fill gaps in our knowledge of the dental morphology of basal Miacidae and provides insight into the functional differences of the carnassial teeth in the diverging Uintacyon and Miacis lineages. It also provides an opportunity to further assess the hypothesis that climactic warming in the earliest Eocene resulted in evolutionary dwarfing of mammalian species; based on three criteria for identifying dwarfed species at least one of the new taxa, U. gingerichi, is consistent with this hypothesis.
Quetzalichthys perrilliatae n. gen. and sp. is described based on five specimens from Lower Cretaceous (Middle-Upper Albian) limestones of the Tlayúa Quarry, near Tepexi de Rodríguez, Puebla, Mexico. This new taxon displays the diagnostic characters of Ionoscopiformes, which consequently designate it as a new member of this order of Mesozoic fishes. Additionally, Quetzalichthys n. gen. shares several derived characters with Ionoscopus and Oshunia, including the presence of more than 15 supraneurals, solid and well-ossified monospondylous vertebrae with two lateral longitudinal oval fossae, thin scales of the amioid type, and the ventral surface of some circumorbital bones being intensely pitted. Quetzalichthys perrilliatae is characterized by three unique characters: 26 abdominal centra, 21 principal dorsal fin rays, and two supraorbitals. Additionally, its unpaired fins and tail show conditions intermediate to those found in Ionoscopus and Oshunia. A cladistic analysis of Ionoscopiformes, including both taxa found in the Tlayúa Quarry (Quetzalichthys and Teoichthys), identifies two monophyletic families within the order, Ophiopsidae (including Ophiopsis, Macrepistius, Teoichthys) and Ionoscopidae (involving Ionoscopus, Oshunia, and Quetzalichthys).
Two new limpets with a caenogastropod-type larval shell are described from the Mississippian (Early Carboniferous) of Australia and assigned to Australoscutula n. gen. of the family Pragoscutulidae. This family has previously been reported only from the Early Devonian of Europe (Czech Republic, Prague Basin). Therefore, it survived the Late Devonian biotic crisis. The fact that one of the earliest certain caenogastropods has a patelliform shell is noteworthy given most other Middle to Late Paleozoic caenogastropods are high-spired or fusiform. Pragosutulidae are interpreted as an early patelliform caenogastropod offshoot derived from coiled ancestors. The Pragoscutulidae are the oldest gastropod limpets with well-preserved larval shells. Their teleoconch is entirely limpet-shaped without helicoid coiling. However, the helicoid turbiniform larval shells suggests that this group evolved from an ancestor with turbiniform or even high-spired adult shell. Moreover, the multi-whorled dextral larval shells show that Pragoscutulidae are Caenogastropoda and document that early Caenogastropoda displayed considerable disparity.