bluuebunny/crossref_metadata_2025 huggingface dataset:
Corynotrypa from the Ordovician of North America: colony growth in a primitive stenolaemate bryozoan
Authors: Taylor Paul D. , Wilson Mark A.
Published: August 2016

Colonies of the runner-like bryozoans Corynotrypa delicatula (James) and C. inflata (Hall) are common encrusters of Middle and Upper Ordovician shells and hardgrounds, especially in Cincinnatian deposits. The simplicity of their zooids contrasts with complexities in the dynamics of colonial organization. Both species have uniserial branches that bifurcate at intervals and, in addition, give rise periodically to lateral ramifications. Although angles of bifurcation and lateral ramification each average about 80°, bifurcations and lateral ramifications are fundamentally different modes of branch multiplication. In C. delicatula new lateral branches have conspicuous secondary zones of astogenetic change distinguished by elongation of successively budded zooids. Unlike bifurcations, the first zooids in lateral branches in Corynotrypa are not linked to the parent branch by a narrow basal canal, and each new lateral branch can be regarded as a distinct subcolonial unit. The ancestrula, described here for the first time in an Ordovician species of Corynotrypa, has a poorly differentiated protoecium and initiates a primary zone of astogenetic change. Colony growth in Corynotrypa was more plastic than in many other bryozoan runners. The systematics of C. delicatula and C. inflata are revised, and a lectotype is chosen for the former species.
Correction of catalog numbers incorrectly cited by Schultz and Falkenbach in oreodont papers published between 1940 and 1968
Authors: Evander Robert L. , Mader Bryn J. , Haase F.
Published: August 2016

Between the years 1940 and 1968 Schultz and Falkenbach published eight papers revising the taxonomy of oreodonts (Merycoidodontidae). Although these papers suffer from many difficulties, including the oversplitting of taxa and the citation of plastically deformed features as diagnostic characters (M. S. Stevens, personal commun.), they remain the primary systematic work on oreodonts produced this century.
Decapod crustaceans from the Semilla Sandstone Member, Mancos Shale (Upper Cretaceous), north-central New Mexico
Authors: Toolson Elizabeth K. , Kues Barry S.
Published: August 2016

The decapods Linuparus grimmeri Stenzel, Protocallianassa mortoni (Pilsbry) and Necrocarcinus (Cenomanocarcinus) vanstraeleni (Stenzel)? are described from the middle Turonian Semilla Sandstone Member, Mancos Shale, of north-central New Mexico. The main specimen of P. mortoni is unusually complete, consisting of a complete left first cheliped, parts of other pereiopods, and most of the abdomen. Both L. grimmeri and P. mortoni are reported for the first time from the southern Western Interior. The stratigraphic range of L. grimmeri is extended upward from the upper Cenomanian, and the range of P. mortoni downward from the Campanian.
Carabocrinid crinoids from the Ordovician of northern Iowa and southern Minnesota
Authors: Brower James C.
Published: August 2016

Four species of carabocrinids from the Ordovician of northern Iowa and southern Minnesota are described, namelyCarabocrinus radiatusE. Billings,C. vancortlandtiE. Billings,C. magnificusSardeson from the Middle Ordovician Dunleith Formation andC. slocomiFoerste from the Upper Ordovician Maquoketa Formation.Carabocrinus radiatusandC. vancortlandtiare also known from the Middle Ordovician of Ontario and Quebec. In addition,C. magnificusandC. vancortlandtiare recorded from the Decorah of the Twin Cities area and the Curdsville Limestone of Kentucky, respectively. Biogeographically, the Middle Ordovician carabocrinids from Iowa and Minnesota are most similar to those from rocks of similar age in the northern Appalachians.

Development of the cup and its component plates inC. slocomiis almost entirely isometric so that the its shape is largely constant regardless of size. This species exhibits ridge canals on the shoulders of the radial plates in the cup. The ridge canals probably served for respiration. As expected, the number of ridge canals and their length increase with positive allometry compared to the size and volume of the cup. Growth of the ridge canals restricts the width of the radial facets.
Oldest shelly fossils from the Taconic Allochthon and late Early Cambrian sea-levels in eastern Laurentia
Authors: Landing Ed , Bartowski Kenneth E.
Published: August 2016

Continental slope facies in eastern New York have the most diverse small shelly faunas known in Laurentian late Early Cambrian strata. Diversity of a lowerElliptocephala asaphoidesassemblage, the oldest body fauna in the Taconic allochthon, reflects turbidity current exhumation, transport, and deposition of phosphatized fossil hash in a proximal facies of the Browns Pond Formation. Phosphatization is linked to the first of twoOlenellusChron intervals with a thickened dysaerobic water mass on the slope. This interval of increased rate of sea-level rise corresponds to development of extensive carbonate belts and onlap of dark shales (e.g., Forteau and lower Kinzers formations) on the east Laurentian shelf.

The assemblage includes two trilobites, archaeocyathan fragments, echinoderm debris, the first edrioasteriod from east Laurentia, and 26 small shelly fossil species. New taxa areAsperconellanew genus andStenotheca taconicanew species (helcionellids);Mackinnonia obliquanew species (pararostroconch);Conotheca laurentiensisnew species,Insolitothecanew genus, andPetasotheca minutanew genus and species (hyoliths); andPlinthokonion?psamminonnew species (agglutinated problematicum).
Primitive cladid crinoids from upper Osagean-lower Meramecian (Mississippian) rocks of east-central United States
Authors: Kammer Thomas W. , Ausich William I.
Published: August 2016

Species of the late Osagean and early Meramecian primitive cladid crinoid generaAtelestocrinus, Barycrinus, Cestocrinus, Costalocrinus, Cyathocrinites, Meniscocrinusn. gen.,Parisocrinus, Pellecrinus, andSaccosomopsisfrom Illinois, Indiana, Iowa, Kentucky, Missouri, and Tennessee are reviewed, redescribed, and redefined from study of type material, museum collections, and field collections. Nomenclatural and systematic acts include the following: 1)Barycrinus spurius(Hall, 1858) is a senior synonym ofCyathocrinus tumidusHall, 1858,C. protuberansHall, 1858, andB. mammatusMeek and Worthen, 1873; 2)B. rhombiferus(Owen and Shumard, 1852a) is a senior synonym ofC. sculptilisHall, 1860,C. thomaeHall, 1860,C. hoveyiHall, 1861a,C. wachsmuthiMeek and Worthen, 1861,B. herculeusMeek and Worthen, 1868,B. pentagonusMeek and Worthen, 1873,B. striatusWorthen, 1875,B. boonvillensisMiller, 1891b,B. formosusMiller and Gurley, 1894,B. washingtonensisMiller and Gurley, 1895, andB. elrodiMiller and Gurley, 1896a; 3)B. magister(Hall, 1858) is a senior synonym ofC. solidusHall, 1861a andB. magnificusMeek and Worthen, 1868; 4)B. stellatus(Hall, 1858) is a senior synonym ofC. bullatusHall, 1858,C. angulatusMeek and Worthen, 1860,C. quinquelobusMeek and Worthen, 1865, andB. astericusVan Sant, 1964; 5)B. crassibrachiatus(Hall, 1860) is a senior synonym ofB. princepsMiller and Gurley, 1890a; 6)B. geometricusMeek and Worthen, 1873, is considered a nomen dubium; 7)B. benedicti(Miller, 1891a) is considered a nomen dubium; 8)Cyathocrinus signatusMiller and Gurley, 1894, is assigned toCestocrinusand is a senior synonym ofCestocrinus striatusKirk, 1940; 9)Cyathocrinites iowensis(Owen and Shumard, 1850) is a senior synonym ofC. malvaceusHall, 1858,C. divaricatusHall, 1858,C. rotundatusHall, 1858,C. viminalisHall, 1861a,C. parvibrachiatusHall, 1861a,C. hamiltonensisWorthen, 1882,C. nodosusWachsmuth and Springer, 1890,C. brevisacculusWachsmuth and Springer, 1890,C. opimusMiller and Gurley, 1890a, andC. gurleyiMiller, 1891a; 10)C. kelloggi(White, 1862) is a senior synonym ofC. subtumidusMeek and Worthen, 1865; 11)C. farleyi(Meek and Worthen, 1866b) is a senior synonym ofC. andersoniMiller and Gurley, 1894,C. granulosusRowley, 1902, andC. snivelyiRowley, 1902; 12)C. harrodi(Wachsmuth and Springer, 1880) is a senior synonym ofC. boonvillensisMiller, 1891b,C. gorbyiMiller, 1892b, andC. astralusKammer, 1984; 13)Meniscocrinusn. gen. is described andM. magnitubusn. sp. is assigned to this new genus; 14)C. labyrinthicusMiller, 1891a, is assigned toParisocrinus; 15)C. intermediusHall, 1858, is assigned toPellecrinus; and 16)C. insperatusLyon, 1869, is assigned toSaccosomopsisand is a senior synonym ofC.?poteriumMeek and Worthen, 1870.
Fossil Octocorallia of the Red Bluff Formation, Lower Oligocene, Mississippi
Authors: Kocurko M. J. , Kocurko D. J.
Published: August 2016

An assemblage of well-preserved octocoral holdfasts and sclerites has been collected from the Red Bluff Formation at the Chickasawhay River, Wayne County, Mississippi. Seven families were identified, utilizing a collection of approximately 1,000 sclerites. Families represented are Telestidae, Nephtheidae, Anthothelidae, Paramuriceidae, Plexauridae, Virgulariidae, and Gorgoniidae. These families, with exception of the Gorgoniidae, are here reported for the first time as fossils from the Gulf Coast region. The collection represents one of the most diverse fossil octocoral assemblages known from a single location.
Physiological, environmental, and mineralogical controls on Mg and Sr concentrations inNautilus
Authors: Mann K. O.
Published: August 2016

Describing the chemical ontogeny of 36 specimens ofNautilusallowed the identification, as well as the determination of the relative effects, of the controls on Mg and Sr concentration in skeletal aragonite. The previously documented trend that aragonite contains higher concentrations of Sr than Mg persists within skeletal structures ofNautilus. This relationship suggests that neither physiological nor environmental controls overwhelm the mineralogical control. Significant differences in Mg and Sr concentrations of nacreous shell, prismatic shell, and septal nacre suggest that these structures may form from extracellular fluids with differing elemental concentrations. Many specimens exhibit greater variability of Mg and Sr concentrations in juvenile portions of the skeleton than in more mature portions. This suggests that either the physiochemical system matures during ontogeny and achieves increasing control over skeletal chemistry or the organism adjusts to the new conditions and behavioral maturation stabilizes elemental concentrations by reducing stress. The decreased growth rate thatNautilusexperiences as it approaches maturity does not effect Mg or Sr concentrations. Differences in combined Mg and Sr concentrations among species ofNautilusindicate that extracellular fluids that produce each skeletal structure are chemically distinct, with the exception of the fluids that produced septal aragnite ofN. belauensisandN. scrobiculatus, and exemplify phyletic control of trace element concentration at the species level. Although significant chemical separation exists among species ofNautilus, sufficient variation and overlap persists in elemental concentrations to make a classification based solely on these two elements ineffective. Significant chemical differences between two sympatric species ofNautilusdemonstrate that physiological systems, and not environmental variables, primarily control elemental concentrations in skeletal aragonite.
Muscle scars and mode of life ofCarinaropsis(Bellerophontoidea, Gastropoda) from the Ordovician of Tennessee
Authors: Peel John S.
Published: August 2016

Muscle scars are described for the first time in the Ordovician bellerophontoidean gastropodCarinaropsisHall. Silica replicas from the Cannon Limestone of Tennessee preserve a pair of muscle scars, with a single elongate scar located on each umbilico-lateral angulation of the shell interior more than half a whorl back from the apertural margin. The scars are similar in general shape and position to muscle scars described inBellerophonde Montfort and the pleurotomarioideanPorcellia woodwardi(Sowerby). In addition to supporting the soft parts within the widely expanded shell, the characteristic internal septum ofCarinaropsisprobably facilitated clamping of the shell aperture against the substrate.
Origin of euconodont elements
Authors: Szaniawski Hubert , Bengtson Stefan
Published: August 2016

Primitive euconodont elements from the Upper Cambrian of Sweden are investigated histologically and compared with co-occurring elements of paraconodonts. The proposed close relationship between the two groups is confirmed. Typical euconodont and paraconodont elements are bridged by intermediate forms. The ontogenetic development of the early euconodont elements shows striking similarities to the evolutionary development from paraconodonts to euconodonts, suggesting that evolution generally followed a peramorphic pattern (“recapitulation”). The conodont crown originated through extension of the growth lamellae around the whole element, accompanied by stronger mineralization. The first denticulation inProconodontusarose when a jagged posterior edge in juvenile specimens was enhanced by the subsequent deposition of growth lamellae, a process comparable to the regeneration of broken tips. The most primitive euconodont elements probably erupted from the epithelium earlier in ontogeny than in more advanced forms. After the appearance of the phosphatic crown, conodont elements underwent a very rapid morphological differentiation.Cordylodusmay have arisen fromProconodontus serratus.
New coral-bivalve association (Actinastrea-Lithophaga) from the Eocene of Florida
Authors: Krumm Debra K. , Jones Douglas S.
Published: August 2016

The endolithic mytilid bivalve, Lithophaga palmerae n. sp., from the Upper Eocene Ocala Limestone of north-central Florida, sheds new light on the evolution of lithophagids with its unspecialized morphology and highly specialized mode of life. Lithophaga palmerae n. sp. inhabited dead and living coral as indicated by orientation evidence. In living coral, the anterior end of the borehole was sealed off with thick, continuous, “false floors” of CaCO3, as the posterior end was extended to keep pace with coral growth. To date, this new species of lithophagid has been found associated with only one host coral, Actinastrea cf. A. incrustans (Duncan). Association with living coral is found today in L. bisulcata (d'Orbigny) and L. dixonae Scott from the Caribbean and in several Red Sea and Indo-Pacific lithophagids. In the fossil record, live-coral boring has been reported from the Miocene of the Vienna Basin of Austria and from the Pleistocene of Grand Cayman Island in the Caribbean. Lithophaga palmerae n. sp. provides a valuable ancestral link in the evolution of Lithophaga by extending the range of live-coral boring back to the Eocene of Florida.
In situ crustoid graptolite colonies from an Upper Ordovician hardground, southwestern Ohio
Authors: Mitchell Charles E. , Wilson Mark A. , St. John James M.
Published: August 2016

In situ colonies of Bulmanicrusta? sp. encrusting the surface of a hardground from the Upper Ordovician Bull Fork Formation provide the first glimpse of the full colony form, habitat, and faunal associates of a crustoid graptolite. Bulmanicrusta? sp. exhibits a runner-type colony form suited to rapid expansion over hard substrates, indicating it was an opportunistic member of the hardground community. This community also included two bryozoans (“Proboscina” and Amplexopora), Cornulites, and crinoids. The Bulmanicrusta? sp. specimens contain numerous graptoblasts (small, thick-walled vesicles) in organic connection with the colony. These objects are located at branch termini and confirm that graptoblasts were not pathological features, but probably were resting cysts produced by the crustoid colony as a normal part of its life cycle. Thus, the presence of graptoblasts supports the interpretation that the Caesar Creek crustoid was adapted to ephemeral or disturbance-prone environments.
Caudichnus: new ichnogenus for a drum-shaped ichnofossil
Authors: D'Alessandro A. , Iannone A.
Published: August 2016

Several specimens of biogenic structures somewhat resembling plug-shaped ichnofossils have been collected in two muddy deposits, Sicilian (Early Pleistocene) in age (Bossio et al., 1987), outcropping near Lecce, southern Apulia, Italy. One sequence is exposed in an unused quarry located at the eastern side of the Cutrofiano–Supersano road, 31 km post; the other one is in an active quarry, southwest of Lecce, near the village of San Pietro in Lama (Figure 1). The diagnostic features of the traces differ from those of the five ichnogenera recognized by Pemberton et al. (1988) for plug-shaped ichnofossils. The minor ichnogenera related to plug-shaped trace fossils, as indicated by those authors, are also different from the present structure. A new ichnogenus is proposed to cover this form.
Clarification of the name-bearing type for “Mesohippus” validus Osborn (Mammalia, Perissodactyla)
Authors: Mader Bryn J.
Published: August 2016

In 1904 Osborn named a new species of Mesohippus, M. validus, based on a specimen consisting of a skull, jaws, and portions of the limbs. Osborn identified this specimen as American Museum of Natural History (AMNH) catalog number 680 and provided a brief description, some measurements, and an illustration.
Biostratigraphic significance and paleogeographic implications of Cambrian fossils from a deep core, Warren County, Ohio
Authors: Babcock Loren E.
Published: August 2016

A deep core from Warren County, Ohio, has yielded numerous fossils of Cambrian age. The specimens, which are among the first recorded from Cambrian rocks of Ohio, suggest revisions in the inferred ages of the Eau Claire and Mount Simon Formations in the Cincinnati Arch region. Trilobites indicative of Dresbachian (late Middle Cambrian to early Late Cambrian) and possibly Franconian (Late Cambrian) age are present in the upper Eau Claire Formation. By implication, the underlying Mount Simon Formation must be of earlier Dresbachian age or perhaps older. Identified trilobites from the Eau Claire Formation seem to be characteristic of inner-shelf lithofacies of Laurentia. Other body fossils from the Eau Claire Formation include inarticulate brachiopods and a graptolite. Body fossils in the lower Knox Dolomite include trilobite sclerites and echinoderm ossicles. Trace fossils are present in both units.
Siliceous microfossils from the warm Late Cretaceous and early Cenozoic Arctic Ocean
Authors: Dell'Agnese Daniel J. , Clark David L.
Published: August 2016

More than 40 species of siliceous microfossils are present in both T-3 core Fl-437 (Cretaceous) and in core Fl-422 (Eocene) from the central Arctic Ocean. Previous identifications of the silicoflagellates were the basis of the ages for these cores, but diatoms of the two cores, previously unidentified, suggest that Fl-437 could be as old as Campanian rather than middle to late Maastrichtian and that Fl-422 may be early to middle Eocene rather than middle to late Eocene. Identification of archaeomonads and ebridians completes the cataloging of the known biosiliceous assemblages of the older Arctic Ocean.

Strong seasonality for the Late Cretaceous and early Cenozoic Arctic Ocean is suggested from alternating layers of vegetative cells and resting spores in both cores. The abundance of fossils is interpreted as evidence for seasonal upwelling in a nutrient-rich and much warmer Arctic Ocean. No evidence of seasonal ice or of ice-rafting is present. The profound climate change from the warmer older Arctic Ocean to the ice-covered condition of the present occurred after deposition of the sediment of Fl-422.
Ostracodes and chronostratigraphic position of the Upper Cretaceous Arkadelphia Formation of Arkansas
Authors: Pitakpaivan Kasana , Hazel Joseph E.
Published: August 2016

The ostracode assemblage of the Arkadelphia Formation, upper Maastrichtian, of southwestern Arkansas is characterized by a well-preserved, relatively diverse, and abundant fauna representing 36 podocopid species and an undetermined number of species of the platycopid genus Cytherella. Thirteen of these account for 85 percent of the fauna. The dominant forms are Cytherella spp., Brachycythere rhomboidalis (Berry, 1925), Haplocytheridea renfroensis Crane, 1965, Haplocytheridea bruceclarki (Israelsky, 1929), and Brachycythere ovata (Berry, 1925), which account for about 57 percent of the specimens found. Other species that are less common, but are characteristic of the Arkadelphia, are Antibythocypris macropora (Alexander, 1929), Ascetoleberis hazardi (Israelsky, 1929), Aversovalva fossata (Skinner, 1956), Brachycythere ledaforma (Israelsky, 1929), Curfsina communis (Israelsky, 1929), Cytheromorpha arbenzi (Skinner, 1956), Escharacytheridea micropunctata (Alexander, 1929), and Veenia arachoides (Berry, 1925). The ostracode assemblage indicates that the Arkadelphia was deposited in the inner sublittoral zone.

The species Veenia parallelopora (Alexander, 1929) and Brachycythere foraminosa Alexander, 1934, are restricted to the Arkadelphia Formation and allow correlation with other Gulf Coastal Plain Upper Cretaceous units. A new ostracode interval zone, the Veenia parallelopora Zone, is proposed. This zone divides the Platycosta lixula Zone.

Calcareous planktic microfossils reported from the Arkadelphia and its correlatives in the Veenia parallelopora Zone indicate that these deposits are late Maastrichtian in age, not middle Maastrichtian as some authors have thought.
New Ediacaran fossils from the Mackenzie Mountains, northwestern Canada
Authors: Narbonne Guy M.
Published: August 2016

The terminal Neoproterozoic Sheepbed and Blueflower Formations at Sekwi Brook in northwestern Canada have yielded two additional taxa, both of them new to North America. Hiemalora cf. H. pleiomorphus Vodanjuk is a tentaculate disc that most likely represents a semi-infaunal polyp. Windermeria aitkeni n. gen. and sp. is an ovate, bilaterally symmetrical, segmented fossil similar to the dickinsoniids; these fossils characterize Neoproterozoic faunas of Australia and the Russian Platform, but had not previously been reported from Laurentia.
Methods for distinguishing carbonized specimens of the presumed cephalopod aptychusSidetes(Spathiocaris) from the plantProtosalvinia(Foerstia)
Authors: Hannibal Joseph T.
Published: August 2016

The purpose of this note is to point out the similarities betweenProtosalvinia (Foerstia)andSidetes (Spathiocaris)and to discuss characters that can be used to distinguish the two taxa.ProtosalviniaClarke, 1885 (Figure 1.1-1.4), also commonly referred to by the junior subjective synonymFoerstia, is a plant fossil that is frequently noted as occurring in Upper Devonian black shale sequences of North America. This taxon has been of great interest to stratigraphers, paleoecologists, plant taxonomists, and plant morphologists over the years (see, for example, Winslow, 1962, p. 7, p. 22, fig. 3; Barron and Ettensohn, 1981, p. 30-31; Matthews, 1983; and Romankiw et al., 1988). Most workers in recent years have consideredProtosalviniato be a marine alga, but there is also evidence for a land plant affinity (Romankiw et al., 1988).
Lithistid sponges from the Late Ordovician Fish Haven Dolomite, Bear River Range, Cache County, Utah
Authors: Rigby J. Keith , Jamison Paul
Published: August 2016

The tricranoclad demosponge Hindia sphaeroidalis Duncan, 1879, is reported as a common silicified sponge in the basal dolomite of the Deep Lakes Member of the Upper Ordovician Fish Haven Formation of northeastern Utah for the first time. A small juvenile orchoclad anthaspidellid, Hudsonospongia? sp., is also the first of that family reported from Fish Haven beds and the Deep Lakes Member. Both taxa are from localities on the eastern slope of Mount Magog, north of Tony Grove Lake, in the Bear River Range, Cache County, east of Logan, Utah.
The environment, biogeography, and origin of the southern African Recent brachiopod fauna
Authors: Hiller Norton
Published: August 2016

The brachiopod fauna that presently lives in the seas off the coasts of Namibia, South Africa, and southern Moçambique comprises 35 named plus seven unnamed species belonging to 26 genera, making it one of the most diverse in the world. Within the fauna are some species that are confined to the warm waters of the east coast, some that are restricted to the cold west coast waters, and others that enjoy a more widespread distribution. The geographic distribution of species is believed to be controlled by the two major oceanographic systems operating off southern Africa, namely, the Agulhas Current on the east and the Benguela Upwelling System on the west.

Among the species that live off the west and south coasts are many that appear to have evolved in situ during times of pronounced environmental stress since the late Miocene. The fauna living off the east coast shows strong similarity with others in the Indian Ocean and it is inferred that many of the species migrated into the South African region by way of the ocean current systems that were established by the mid-Pliocene.

Descriptions ofXenobrochus naudeiand the previously undescribedArgyrothecasp. andAmphithyriscf.A. richardsonaeare provided.
Late Ordovician nearshore faunas and depositional environments, northwestern Maine
Authors: Pollock Stephen G. , Harper David A. T. , Rohr David
Published: August 2016

The Little East Lake Formation represents a spectrum of Late Ordovician (Ashgill) nearshore environments. These physical environments are characterized by a variety of quartz- and feldspar-rich sandstone and slate. Depositional environments include neritic nearshore, beach, tidal flat, and alluvial(?). The beach and neritic nearshore environments contain a variety of fossil invertebrates. The majority of the brachiopod fauna is confined to two taxa:Eodinobolus rotundusHarper, 1984, andDalmanella testudinaria ripaeMitchell, 1978(inCocks, 1978). Some of the specimens have been broken and abraded suggesting transport within the beach swash zone. Gastropods includeLophospiracf.L. milleri(Hall),Lophospira(?),Trochonemellacf.T. notabilis(Ulrich and Scofield), andDaidia cerithioides(Salter). Tidal-flat environment contains the trace fossilsPalaeophycusandPlanolites.

The Late Ordovician (Caradoc and Ashgill) sedimentary basins developed subsequent to the collisional Taconian orogeny, wherein an arc accreted to the eastern Laurentian margin. Prior paleomagnetic reconstructions place the southeastern continental margin of Laurentia at approximately 25° south latitude during the Late Ordovician. Using these reconstructions, the siliciclastic Ashgill rocks discussed here would have been deposited in an elongated, northeast-trending basin on the southeastern Laurentian margin. The fauna developed along this margin, but in contrast to possibly adjacent Irish and Scottish assemblages, was located in much shallower water.
The H. A. Nicholson Collection of Paleozoic stenolaemate bryozoans: comparison of cladistic and phenetic classifications
Authors: Pachut Joseph F. , Anstey Robert L. , Horowitz Alan S.
Published: August 2016

Until the late 1960's, most of Nicholson's types of Paleozoic bryozoans were not available for study. We present a set of coded characters of many of Nicholson's types, which should assist in bringing his species into conformity with current taxonomic standards so that his species can be consistently recognized and used in biostratigraphic, paleobiogeographic, and evolutionary studies.

Cladistic and phenetic analyses of these species permit comparisons between inferred phylogenies of Nicholson specimens, adaptive morphospace, and treatise-based systematic relationships. Specimen-based cladistic and phenetic analyses of Nicholson's species both produce clusters that are congruent with existing family-level taxonomic assignments of species in the collection. However, cladistic analysis more fully retrieves the pattern of branching, or degree of relatedness, among higher taxa. Phenetic clusters represent adaptive peaks in morphospace for these specimens, but higher level “phenons” are strongly affected by multiple evolution of the same character states.
A new obolellid brachiopod from the Lower Cambrian of Morocco
Authors: Geyer Gerd
Published: August 2016

A new genus and species of obolellid brachiopod,Brevipelta chouberti, is described from the Early Cambrian of Morocco. It is a useful index fossil for the upperChoubertellaZone and theDaguinaspisZone in Morocco. Additionally discussed are taphonomic aspects that lead to the question whether the shell may have been weakly calcified compared to other obolellid brachiopods and the calcareous part may have been composed of aragonite crystallites, or whether the preservation ofBrevipeltais due to facile solubility of a calcitic shell substance.Brevipelta choubertirepresents not only the oldest described Early Cambrian brachiopod from Africa, but one of the oldest obolellid brachiopods known worldwide.
The phylogenetic position of the Tyrannosauridae: implications for theropod systematics
Authors: Holtz Thomas R.
Published: August 2016

Tyrannosaurids are a well-supported clade of very large predatory dinosaurs of Late Cretaceous Asiamerica. Traditional dinosaurian systematics place these animals within the infraorder Carnosauria with the other large theropods (allosaurids, megalosaurids). A new cladistic analysis indicates that the tyrannosaurs were in fact derived members of the Coelurosauria, a group of otherwise small theropods. Despite certain gross cranial similarities with the large predators of the Jurassic and Early Cretaceous, the Late Cretaceous tyrannosaurids are shown to be the sister group to ornithomimids and troodontids, which share a derived condition of the metatarsus. This clade is found to be nested within Maniraptora, which is a more inclusive taxon than previously recognized. The atrophied carpal structure found in tyrannosaurids and ornithomimids is derived from a maniraptoran condition with a large semilunate carpal, rather than from the plesiomorphic theropod morphology.

The taxa “Carnosauria” and “Deinonychosauria” (Dromaeosauridae plus Troodontidae) are shown to be polyphyletic, and the Late Jurassic African formElaphrosaurusis found to be the sister taxon to Abelisauridae rather than a primitive ornithomimosaur. Purported allosaurid-tyrannosaurid synapomorphies are seen to be largely size-related, present in the larger members of both clades, but absent in smaller members of the Tyrannosauridae. The remaining giant tetanurine theropods(MegalosaurusandTorvosaurus)were found to be progressively distant outgroups to an allosaurid-coelurosaur clade. The inclusion of the Tyrannosauridae within Maniraptora suggests a major adaptive radiation of coelurosaurs within Cretaceous Asiamerica comparable to contemporaneous radiations in various herbivorous dinosaurian clades.
Geology and taphonomy of theCoelophysisquarry, Upper Triassic Chinle Formation, Ghost Ranch, New Mexico
Authors: Schwartz Hilde L. , Gillette David D.
Published: August 2016

TheCoelophysisdinosaur quarry at Ghost Ranch, near Abiquiu, New Mexico, is unique among Triassic fossil sites for its yield of numerous complete and partial skeletons of a single species of theropod dinosaur (Coelophysis bauri).Since its discovery in 1947 by E. H. Colbert in the red siltstone beds of the Upper Triassic Chinle Formation, the quarry has yielded the remains of at least 1,000 individuals from approximately 30 cubic meters of excavated material. The main bone-bearing strata are abandoned channel deposits that are part of a siltstone overbank sequence. TheCoelophysisremains found at the quarry are remarkably whole and well preserved, though they range in degree of articulation from complete skeletons to isolated limbs and bones. Skeletons, partial skeletons, and bones are crudely aligned and show little evidence of predator or scavenger disturbance or surface weathering. Geologic and taphonomic evidence suggests that the dinosaurs preserved in the Ghost Ranch quarry were transported to the site as carcasses by fluvial currents. The carcasses blocked a small channel and were subsequently buried by silts. Petrographic study and neutron activation analysis reveal no evidence of volcanic ash, paleopathologic osteology, or unusual chemistry in the quarry bone and sediments. The virtual monospecificity, taphonomy, and ecology of the assemblage suggest that the dinosaurs perished due to a regional environmental crisis, such as drought.
Influence of freshwater flux on 87Sr/86Sr chronostratigraphy in marginal marine environments and dating of vertebrate and invertebrate faunas
Authors: Bryant J. Daniel , Jones Douglas S. , Mueller Paul A.
Published: August 2016

87Sr/86Sr chronostratigraphy is an important tool for dating and correlating vertebrate and invertebrate faunas preserved in marginal marine sequences. Freshwater flux in marginal marine environments can influence the 87Sr/86Sr of mollusks and, consequently, Sr-chronostratigraphic interpretations based upon them. To appraise the potential problem we have used a two-component mixing equation to evaluate levels of “measurable effects” (defined as ±5 × 10-5 departure from the marine 87Sr/86Sr ratio) in marginal marine environments. A measurable effect occurs at 12 parts per thousand salinity for a weighted world average river, but can occur at salinity > 34 ppt for rivers draining basins with ancient granitic rocks. Predictions were tested with analyses of mollusks from estuaries in the Mississippi Sound and coastal Florida. Analyses document the largely regular variation in 87Sr/86Sr predicted, but also show that a simple two-component model cannot account for all of the variation. Carbonates formed in restricted marine settings may not record a marine 87Sr/86Sr signal, emphasizing the need to consider freshwater flux for 87Sr/86Sr chronostratigraphy.
Taxonomy and correlation of Lower Triassic (Spathian) segminate conodonts from Oman and revision of some species ofNeospathodus
Authors: Orchard M. J.
Published: August 2016

Exceptionally well preserved Lower Triassic conodonts from Oman include an array ofNeospathodusspecies, many of which are new. Those from the upper Lower Triassic, or Spathian, are described in conjunction with a restudy of conodont type material from Chios, Greece, and an assessment of contemporary collections from Pakistan and western North America. The taxonomic scope of three key species from Chios,Neospathodus homeri, N. triangularis, andN. gondolelloides, is revised. Seven new species are described from Oman:N. abruptus, N. brevissimus, N. brochus, N. crassatus, N. curtatus, N. pusillus, andN. symmetricus;and one new species,N. clinatus, is described from Pakistan. The alliedIcriospathodus collinsoniis also described from Oman. The occurrence and range ofNeospathodusspecies are presented in the context of the ammonoid succession in the Spathian of North America. BothN. homeriandN. triangularis, as revised, have shorter ranges and are more age diagnostic than previously thought.Neospathodus gondolelloidesis a distinct taxon, and not synonymous withChiosella timorensis.Five informal faunal divisions are identified based onNeospathodusand allied species. In ascending stratigraphic order, these are typified byIcriospathodus collinsoni, Neospathodus homeri, N. triangularis, N. symmetricus, andN. gondolelloides.Oman collections represent three of these faunas, which occur also in theColumbitesthroughProhungarites/Subcolumbitesammonoid beds of western U.S.A.
Re-evaluation of the genusXanthosiaBell, 1863 (Decapoda: Brachyura: Xanthidae) and description of two new species from the Cretaceous of Texas
Authors: Hopkins C. Schweitzer , Salva Eric W. , Feldmann Rodney M.
Published: August 2016

Description of two new species of the brachyuran genusXanthosiaBell, 1863, from the upper Albian to Cenomanian Weno and Pawpaw formations from Tarrant County, Texas, increases the number of species in the genus to fifteen.Xanthosiahas been recognized in England, the Netherlands, Madagascar, and in in the states of New Jersey, South Dakota, and Texas. The geologically oldest species from England gave rise to species from North America, Europe, and Madagascar. One group of species, with representatives from South Dakota, New Jersey, and Madagascar, may represent a separate taxon. The species “Xanthosia” robertsiSecretan is herein removed from the genus and placed within the Portunidae, not the Xanthidae.
Stasis and extinction of Silurian (Llandovery–Wenlock) trilobite associations related to oceanic cyclicity
Authors: Mikulic Donald G. , Kluessendorf Joanne
Published: August 2016

Silurian trilobites of the central United States belong to a series of temporally-successive associations which appeared abruptly, maintained taxonomic stasis for a time, and then disappeared abruptly. Their disappearance resulted from global perturbations of short-term duration and moderate magnitude, which caused substantial taxonomic replacement but no reorganization of major ecosystems. The most significant extinction and replacement in Silurian trilobite associations in the study area occurs near the Llandovery–Wenlock boundary. This turnover in trilobite associations appears to correspond to Jeppsson's Ireviken Event in his model of oceanic and climatic cyclicity. Major sea-level changes earlier in the Llandovery did not have a similar impact on trilobite associations.
Ostracodes from the Naco Formation (Upper Carboniferous) at the Kohl Ranch locality, central Arizona
Authors: Lundin Robert F. , Sumrall Colin D.
Published: August 2016

The Kohl Ranch locality in the Naco Formation (Upper Carboniferous, Desmoinesian) of central Arizona contains an ostracode fauna of 13 species of which three are left in open nomenclature because of inadequate materials; all of the others have been previously described. This fauna is strongly dominated by Hollinella (Hollinella) bassleri (Knight, 1928), Cavellina pulchella Coryell, 1928, Bairdia whitesidei Bradfield, 1935, and Bairdiacypris (Fabalicypris) regularis Cooper, 1946. Present in moderate numbers are Amphissites (Amphikegelites) roundyi Knight, 1928, Moorities minutus Warthin, 1930, and Healdia simplex Roundy, 1926. Pseudobythocypris tomlinsonella Cooper, 1946, Bairdia hoxbarensis Harlton, 1927, Sulcella sulcata Coryell and Sample, 1932, and species of Oliganisus, Sansabella and Chamishaella are represented by only small numbers of specimens. The dominant and moderately abundant species indicate a shallow, offshore environment of deposition. The known geographical range of all species present in the fauna is extended into central Arizona.
Early Cambrian sponges from Vermont and Pennsylvania, the only ones described from North America
Authors: Rigby J. Keith
Published: August 2016

Early Cambrian Leptomitus zitteli Walcott, 1886, is a tubular, double-walled, demo-sponge from the Parker Slate of Vermont and is one of the few intact sponges of that age known. It occurs with skeletal fragments of ?Protospongia hicksi Hinde, 1887. Hazelia walcotti (Resser and Howell, 1938) is a thin-walled, tubular sponge with crudely clustered oxeas in a thatched skeleton. It is known from the Kinzers Formation of Pennsylvania. Early occurrences of Leptomitus and Hazelia indicate that at least these two lineages had diverged by the latter part of the Early Cambrian. The impression described as Leptomitus minor by Resser and Howell (1938) lacks spicules and is not a sponge.
A new crab, Prehepatus werneri (Crustacea: Decapoda), from the Maastrichtian of the Netherlands
Authors: Fraaye R. H. B. , Collins J. S. H.
Published: August 2016

A new calappid crab, Prehepatus werneri n. sp., is described from the Upper Maastrichtian of Limburg, The Netherlands. This species represents the first European and youngest known member of the genus. The appearance of this species seems to correspond with an increasing Tethyan influence in the type-Maastrichtian area.
Baiotomeus, a new ptilodontid multituberculate (Mammalia) from the middle Paleocene of western North America
Authors: Krause David W.
Published: August 2016

Baiotomeus is a new genus of ptilodontid multituberculate from the late Torrejonian Land-Mammal Age (late middle Paleocene) of western North America. Baiotomeus douglassi (Simpson), the type species, has been assigned, at one time or another, to Ptilodus, Mimetodon, and Neoplagiaulax. In addition, a second, new species, B. lamberti, from three localities in the Medicine Rocks area of southeastern Montana is reported here. The Medicine Rocks localities are tentatively assigned a latest Torrejonian age, younger than localities yielding B. douglassi and younger than previously suggested on the basis of plesiadapid primates.

Multituberculates appear to have attained their highest species richness during the Torrejonian Land-Mammal Age, but the discovery of B. lamberti illustrates that our knowledge of multituberculate diversity is incomplete from even that interval of time.
Miocene Tayassuidae (Mammalia) from the Chesapeake Group of the Mid-Atlantic coast and their bearing on marine-nonmarine correlation
Authors: Wright David B. , Eshelman Ralph E.
Published: August 2016

Four morphologically distinct tayassuid species are present in the marine strata of the lower Chesapeake Group in Maryland and Virginia. The oldest of these, an unnamed species, occurs in bed 2 of the Calvert Formation and is the only terrestrial mammal yet known from this unit. In the upper Calvert and lower Choptank Formations three tayassuid species resemble closely in size and morphology taxa known from the middle and upper Miocene Olcott and Valentine Formations in Nebraska. “Cynorca proterva” and “Prosthennops” xiphidonticus are present in beds 10 and 14, respectively, of the Calvert Formation. “Prosthennops” niobrarensis occurs in bed 17 of the Choptank Formation. These taxa, considered together with the other known terrestrial mammals from the Chesapeake Group, indicate the following correlations with land mammal faunas from western North America: bed 2, ?late Arikareean or early Hemingfordian; bed 10, late Hemingfordian or early Barstovian; bed 14, early late Barstovian; bed 17, late late Barstovian. These correlations are largely concordant with micropaleontogical correlations for the Chesapeake Group, but the age indicated for bed 17 is younger than an age estimate based on diatoms.
Upper Devonian (Frasnian) rugose corals from New York State
Authors: Sorauf James E.
Published: August 2016

West Falls Group strata (Chemung facies) of Upper Devonian (Frasnian) age in New York State reflect sedimentation on a storm dominated sandy shelf. Rugose corals occur in storm deposited coquinites rich in bioclastic debris and are abundant locally, although representing only three species,Tabulophyllum orientale(Stumm),Macgeea ponderosaStumm, andDisphyllum caespitosum(Goldfuss). TheTabulophyllumandMacgeeaspecies are both characterized by large amounts of stereome (biogenic calcite) in the apical part of the corallite, perhaps useful in stabilizing corallites in the sediment.
Lower Cambrian trilobites, zonation, and correlation of the Puerto Blanco Formation, Sonora, Mexico
Authors: McMenamin Mark A. S.
Published: August 2016

The Lower Cambrian sequence south of the town of Caborca in northwestern Sonora, Mexico, has yielded the trilobites Nevadia ovalis n. sp. and Judomia orbis n. sp., plus an incomplete fallotaspid cephalon. The Nevadella Zone of Fritz (1972) can now be recognized in the Puerto Blanco Formation, and fossils from the middle part of the formation strongly suggest the presence of the Fallotaspis Zone. The new fossils permit improved correlation of the Mexican sequence to sections in the United States and to Lower Cambrian stages of China and the Soviet Union.
Tikisuchus romeri, a new rauisuchid reptile from the Late Triassic of India
Authors: Chatterjee Sankar , Majumdar Pranab K.
Published: August 2016

Tikisuchus romeri n. gen. and sp. is a rauisuchid thecodontian from the Late Triassic Tiki Formation of India and is the first rauisuchid material to be recorded from Asia. The skull is very large in relation to the presacral length and is equipped with sharp, serrated teeth. The astragalus has a very high dorsal process and the calcaneal tuber is short; the ankle joint is of “crocodile-normal” type.

The rauisuchids were the dominant terrestrial predators during the Triassic and shared similar ecological niches with the emerging theropods. The agility and superior locomotion of theropods may have contributed to their success and to their eventual replacement of the rauisuchids at the end of the Triassic.
An associated partial skeleton of Symbos cavifrons (Artiodactyla: Bovidae) from Montezuma County, Colorado
Authors: Mcdonald Jerry N. , Neusius Sarah W. , Clay Vickie L.
Published: August 2016

A partial cranium and axial skeleton of an individual Symbos cavifrons were excavated in 1983 from the Mesa Verde Loess on Grass Mesa, Montezuma County, Colorado. Parts of at least 24 bones were recovered, including the first complete set of cervical vertebrae known for Symbos cavifrons. This individual, radiocarbon dated at 15,970 ± 155 yr B.P. (SI-6137), contributes to the definition of the southwestern edge of the range of the species and provides new information about the nature of the vertebral column. Pathologic constriction of the transverse canals is evident in the third and seventh cervical vertebrae. The pattern of bone distribution suggests that carnivores consumed part of this animal. The radiocarbon date also establishes the last major episode of loess deposition in the Four Corners region of the southwestern United States.
Latest Devonian–Earliest Mississippian nearshore trace-fossil assemblages from West Virginia, Pennsylvania, and Maryland
Authors: Bjerstedt Thomas W.
Published: August 2016

Trace fossils are used in deposystem analysis of Late Devonian–Early Mississippian nearshore facies in the north-central Appalachian Basin. These nearshore facies resulted from separate transgressions during latest Devonian (Cleveland Shale) and earliest Mississippian (Sunbury Shale) time. Emphasis is placed on a well-exposed section at Rowlesburg, West Virginia, where the Oswayo, Cussewago Sandstone, and Riddlesburg Shale Members of the Price Formation are exposed.

The Oswayo Member at Rowlesburg preserves an offshore-to-lower shoreface transition in a complex of euryhaline, protected-bay, lagoon, and possible estuarine facies. Cruziana is common and occurs along with Arthrophycus, Bifungites, Chondrites, Planolites, Palaeophycus, Rhizocorallium, Rosselia, Rusophycus, and Skolithos in intensely bioturbated mudstone, siltstone, and sandstone. These lithologies were deposited below fair-weather wave base and grade upsection to upper shoreface facies comprised of thick, horizontally-laminated sandstones with thinner, burrowed mudstone interbeds. Upper shoreface traces consist of Arenicolites, Cruziana, Diplocraterion, Dimorphichnus, Planolites, Thalassinoides, and Skolithos. Skolithos “pipe rock” sandstones occur at the toe of upper shoreface facies. Eastward the Oswayo Member grades into a restricted-bay facies and finally into beach and tidal flat facies near its stratigraphic wedge-out in eastern West Virginia and western Maryland. The Cussewago Sandstone Member at Rowlesburg overlies the Oswayo and is bounded at the top by a disconformity. The Cussewago contains Arenicolites, Isopodichnus, Phycodes, Planolites, and Skolithos in upper shoreface sandstones possibly related to deposition in deltaic or tidal channel systems.

Regionally, the Riddlesburg Shale records a range of euryhaline environments in shallow-shelf, open-bay, and probable estuarine facies. The Riddlesburg Shale Member at Rowlesburg is comprised of dark-grey silty shales, siltstones, and hummocky cross-stratified sandstones. Trace fossils include Bergaueria, Bifungites, Fustiglyphus?, Helminthopsis, Planolites, and Skolithos. Lithofacies of the Riddlesburg Shale in West Virginia were markedly influenced by a syndepositionally active basement feature, the West Virginia Dome. Riddlesburg-age shoreface sandstones deposited on the crest of the Dome contain apparent omission surfaces with common Rhizocorallium and Arenicolites, Cruziana?, Planolites, and Skolithos.