bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cambrian–Ordovician boundary in the Taconic allochthon, eastern New York, and its interregional correlation
Authors: Landing Ed 
Published: August 2016

Cambrian–Ordovician boundary interval dendroid graptolites and conodonts occur in continental slope facies in the Taconic allochthon. The upper part of the Hatch Hill Formation has lowest Ordovician (lowest Tremadocian) nematophorous dendroid and lower Fauna B-aspect conodont assemblages with Cordylodus caseyi (emend.) and Iapetognathus preaengensis. Comparable dendroid-conodont faunas occur in Baltoscandia, northeastern China, and western Newfoundland; this suggests that no diachroneity can be demonstrated between the lowest occurrences of Rhabdinopora flabelliformis in a number of faunal provinces.A practical and correlatable Cambrian–Ordovician boundary stratotype horizon defined by the lowest occurrence of a Rhabdinopora flabelliformis assemblage within an interval with lower Fauna B-aspect conodonts is advocated. A biostratigraphic horizon defined by conodonts has far less utility due to strong lithofacies-conodont biofacies linkages, unresolved problems with the species-level taxonomy of cordylodans, and possible diachronous first-appearances of Cordylodus species. Because the areally most extensive Cambrian–Ordovician boundary sequences are siliciclastic-dominated (Avalonian, Baltoscandian, Gondwanan-Hercynian platforms and shale-dominated slope sequences), the lowest local occurrence of R. flabelliformis assemblages provides a practical and traditional definition for the base of the Ordovician System and Tremadocian Series in regions where conodonts are rare or recoverable only with difficulty.Strata correlative with the Cambrian–Tremadocian boundary interval are not represented across most of Laurentia. In this region, the “Sauk III Subsequence” locally has an important unconformity within it, and lower Tremadocian-equivalent rocks can unconformably overlie units as low as the Proterozoic. The earliest Ordovician featured a relatively simple eustatic history characterized by an “early Tremadocian onlap”; no compelling evidence supports a eustatic fall-rise couplet, or “Black Mountain eustatic event,” in this interval. Available stratigraphic information is reinterpreted to demonstrate an initially slow and subsequently higher rate of continued sea level rise in the Cambrian–Ordovician boundary interval.
Specific, generic, and familial diversity of Devonian bryozoans
Authors: Horowitz Alan Stanley , Pachut Joseph F. 
Published: August 2016

Lack of an adequately calibrated Devonian time scale precludes satisfactory comparisons of Recent and Devonian bryozoan diversities. Nevertheless, Devonian bryozoans apparently are 3–100 times less diverse than Recent bryozoans. This variation is a function of how Devonian time is divided (whole period, stages, per million years) as well as the diverse skeletal architecture of cheilostome bryozoans, the most abundant Recent bryozoan order.The Givetian has the largest specific, generic, and familial diversity of any Devonian stage and the drop in bryozoan diversity from the Givetian to the Frasnian is greater than the rise or fall of diversity between any other adjacent stages. Diversity hardly changes among bryozoans across the Frasnian–Famennian boundary. Among bryozoans the Givetian–Frasnian extinction was a major event.Devonian taxonomic diversity is less than nomenclatorial diversity, although both exhibit the same trends from stage to stage during the Devonian. The amount of difference between the two measures of diversity is probably a reflection of the intensity of research on Devonian Bryozoa, especially revisionary studies of previously described faunas. Monographic bursts in diversity are present and are a measure of the episodic character of taxonomic studies on less popular phyla. Examination of the literature commonly provides a finer stratigraphic resolution than indicated in compilations such as the Zoological Record.Although some significant areas of the exposed continents have not received adequate study, Devonian bryozoans show marked geographic changes in diversity that can not be ascribed entirely to lack of study.
Early Silurian rhodocrinitacean crinoids (Brassfield Formation, Ohio)
Authors: Ausich William I. 
Published: August 2016

Six Early Silurian Rhodocrinitacea (Crinoidea, Camerata) are recognized from the Brassfield Formation of Ohio. Previously only a single Early Silurian rhodocrinitacean was known. The new forms include Kyreocrinus constellatus n. gen., n. sp.; Rhachicrinus wrighti n. gen., n. sp.; Silfonocrinus siluricus n. gen., n. sp.; Stereoaster squamosus Foerste; Xysmacrinus greenensis n. gen., n. sp.; and Turbocrinus punctum n. gen., n. sp. Rhachicrinus and Silfonocrinus are assigned to the Opsiocrinidae, which previously included two Devonian genera; Turbocrinus is assigned to the Anthemocrinidae; and Kyreocrinus, Stereoaster and Xysmacrinus are assigned to the Rhodocrinitidae.The Opsiocrinidae are thought to be derived from the Reteocrinidae; and a possible basis for subdividing the Rhodocrinidae is proposed, based on the arms, plating in regular interrays, presence of median ray ridges and calyx shape.
New Neritidae from southwestern North America
Authors: Woods Alan J. Cushing , Saul L. R. 
Published: August 2016

In southwestern Baja California Norte a new species of Early Tertiary Tethyan gastropod, Velates, V. vizcainoensis n. sp., occurs with a previously unknown intertidal molluscan fauna suggestive of an unprotected coastline of probable Paleocene age. Comparison of Velates vizcainoensis n. sp. to other forms previously assigned to Velates from southwestern North America suggests that “Nerita” cuneata Gabb of Late Cretaceous age probably belongs in Neritina (Dostia), as do N. (D.) aff. N. (D.) cuneata and N. (D.) escondita n. sp.Velates is probably derived from typical Otostoma and is an early Tertiary genus. Velates californicus Vokes, although originally described as being from the Llajas Formation of middle Eocene age, is from the upper Santa Susana Formation and probably is of late Paleocene age at its type locality.Two other neritid gastropods are present in the fauna with Velates vizcainoensis; namely, Corsania (Januncia) Janus n. subgen., n. sp. and Nerita (Theliostyla) n. sp.(?). Corsania Vidal, 1917, is a genus distinct from Otostoma and ranges from Early Cretaceous to Paleocene. Januncia n. subgen. has a Tethyan distribution and ranges from Maastrichtian through Paleocene.
A new anomalous giant limpet from the Oregon Eocene (Mollusca: Patellida)
Authors: Lindberg David R. , Hickman Carole S. 
Published: August 2016

Cellana amplan. sp. from late Eocene rocks in Oregon is the first New World record of a genus and family heretofore considered to have radiated in Australia and the mid-Pacific. Re-examination of some other Eocene limpets from the Pacific Northwest reveals that species previously assigned toAcmaeabelong inPatelloidaandSiphonaria. Thus, all three major components of the modern Australian limpet guild were present in the late Eocene of western North America along a coastline occupied today by acmaeid limpet guilds. Re-examination of a large Pliocene‘Patella’from South America shows the shell structure of aCellanaand constitutes a second documentation of a large nacellid limpet in the New World Tertiary.Although the taxonomy of modern limpets is founded on anatomical characters, shell structure characters are sufficient to identify genera and families directly in the fossil record. Re-evaluation and reclassification of fossil limpets using shell structure contributes not only to a better understanding of the phylogeny of major limpet groups but also provides a powerful tool for elucidating the evolutionary, biogeographic, and ecologic development of the complexly structured limpet guilds of differing taxonomic composition that dominate rocky intertidal habitats throughout the world.
Sinemurian (Early Jurassic) ammonite fauna from the Guangdong region of southern China
Authors: Wang Yi-Gang , Smith Paul L. 
Published: August 2016

An ammonite fauna from the southern coastal volcanic region of the Chinese Jurassic contains representatives of the genera Sulciferites, Coroniceras, Arnioceras, Asteroceras, Eparietites, and Juraphyllites. The ammonite-bearing strata of the Jinji Formation were deposited during the Sinemurian (Bucklandi to Obtusum zones), whereas the lower member has yielded marine Hettangian bivalves. The Jinji Formation is underlain by terrestrial Triassic rocks of the Xiaoping Formation and overlain by terrestrial Middle Jurassic rocks of the Baizushan Group.Correlative Early Jurassic rocks are shown to occur across eastern Guangdong Province, and probably as far north as southern Hunan Province. Although this marine phase of deposition may correspond broadly to a eustatic sea level rise, the exact role of local tectonic events has still to be assessed.
Middle Tertiary marsupials (Mammalia) from North America
Authors: Korth William W. 
Published: August 2016

All species of North American marsupials from the Chadronian through Hemingfordian are reviewed. Most North American species of didelphids previously referred toPeratheriumare allocated toHerpetotherium.Five species ofHerpetotheriumare recognized.The ChadronianPeratherium donahoeiHough is synonymized withHerpetotherium valens(Lambe). The Orellan speciesHerpetotherium stevensoniCope is resurrected and referred, along with the ChadronianPeratherium titanelixMatthew, to a new genus,Copedelphys.BothCopedelphysandHerpetotheriumcan be derived from known Duchesnean species ofPeratheriumfrom North America.Two genera of peradectids are recognized,NanodelphysMcGrew andDidelphidectesHough.Nanodelphys minutusis synonymized with“Herpetotherium” huntiCope and a second species ofNanodelphysis recognized from the Arikareean, though not named.
Late Eocene chemosynthetic? bivalves from suspect cold seeps, Wagonwheel Mountain, central California
Authors: Squires Richard L. , Gring Michael P. 
Published: August 2016

An anomalous pair of small, isolated calcareous sandstone bodies in the middle member of the upper Eocene Wagonwheel Formation, Wagonwheel Mountain, of the San Joaquin Valley, California, contain numerous articulated specimens of soft-bottom-dwelling bivalves. The lucinid bivalve Epilucina washingtoniana (Clark, 1925) dominates the fauna, which also sparingly contains the thyasirid bivalve Conchocele bisecta (Conrad, 1849) and the vesicomyid bivalve Vesicomya (Vesicomya) aff. V. (V.) tschudi Olsson, 1931.The fossils in the pair of calcareous sandstone bodies, which are surrounded by deep-water silty mudstone barren of megafossils, most likely represent cold-seep communities in the upper bathyal environment. These cold seeps apparently were formed by diffusive flow through coarse sand-fill material in submarine channels.Epilucina washingtoniana was previously known only from upper Eocene rocks on the Olympic Peninsula, Washington, and in Santa Barbara County, southern California. This species, along with a late Eocene species from Colombia, South America, are the earliest representatives of Epilucina. The Wagonwheel Formation contains one of the earliest records of Conchocele bisecta, which is a widespread Cenozoic fossil and is extant in the north Pacific. The species of Vesicomya in the Wagonwheel Formation is the earliest record of Vesicomya s.s. and has close affinity to Vescicomya (Vesicomya) tschudi Olsson, 1931, from the upper Oligocene of northwestern Peru, South America. As in the case of Conchocele bisecta, Vesicomya s.s. has not been reported previously from the Eocene of California.
The “evolution” of Anomalocaris and its classification in the arthropod class Dinocarida (nov.) and order Radiodonta (nov.)
Authors: Collins Desmond 
Published: August 2016

The remarkable “evolution” of the reconstructions of Anomalocaris, the extraordinary predator from the 515 million year old Middle Cambrian Burgess Shale of British Columbia, reflects the dramatic changes in our interpretation of early animal life on Earth over the past 100 years. Beginning in 1892 with a claw identified as the abdomen and tail of a phyllocarid crustacean, parts of Anomalocaris have been described variously as a jellyfish, a sea-cucumber, a polychaete worm, a composite of a jellyfish and sponge, or have been attached to other arthropods as appendages. Charles D. Walcott collected complete specimens of Anomalocaris nathorsti between 1911 and 1917, and a Geological Survey of Canada party collected an almost complete specimen of Anomalocaris canadensis in 1966 or 1967, but neither species was adequately described until 1985. At that time they were interpreted by Whittington and Briggs to be representatives of “a hitherto unknown phylum.”Here, using recently collected specimens, the two species are newly reconstructed and described in the genera Anomalocaris and Laggania, and interpreted to be members of an extinct arthropod class, Dinocarida, and order Radiodonta, new to science. The long history of inaccurate reconstruction and mistaken identification of Anomalocaris and Laggania exemplifies our great difficulty in visualizing and classifying, from fossil remains, the many Cambrian animals with no apparent living descendants.
Microborings and growth in Late Ordovician halysitids and other corals
Authors: Elias Robert J. , Lee Dong-Jin 
Published: August 2016

Microborings in the Late Ordovician tabulate coralsCatenipora rubra(a halysitid) andManipora amicarum(a cateniform nonhalysitid) and in an epizoic solitary rugose coral differ from nearly all of those previously reported in Paleozoic corals. These microborings were formed within the coralla by endolithic algae and fungi located beneath living polyps. Comparable structures in the Late Ordovician tabulateQuepora?agglomeratiformis(a halysitid) represent algal microborings, not spicules, and halysitids are corals, not sponges as suggested by Kaźmierczak (1989).Endolithic algae in cateniform tabulates relied primarily on light entering through the outer walls of the ranks rather than through the polyps; lacunae within coralla permitted appropriate levels of light to reach many corallites. The direction of boring was determined by corallum microstructure and possibly also by the distribution of organic matter within the skeleton. There is an apparent inverse correlation between boring activity and coral growth rate.The location and relative abundance of pyritized microborings within calcareous coralla can be established quantitatively and objectively from electron microprobe determinations of weight percent sulfur along appropriate traverses of the coral skeleton. The distribution of such microborings inCatenipora rubraandManipora amicarumis comparable to algal banding in modern corals; this is the first report of such banding in the interiors of Paleozoic corals. Change in the intensity of boring within each corallum was evidently a response to variation in the linear growth rate of the coral, or to fluctuation in an environmental factor (perhaps light intensity) that could control both algal activity and growth rate in these corals. Change in the algal boring intensity and linear growth rate of the coral was generally but not always seasonal and usually but not invariably associated with change in the density of coral skeletal deposition.Cyclic bands of boring abundance maxima within fossil colonial corals provide a measure of annual linear growth comparable to the widely accepted method based on skeletal density bands. Algal bands are more sporadically developed than density bands within and among coralla, thus increasing the difficulty of interpretation. Fluctuations in the abundance of algal microborings apparently provide a detailed record of changes in the linear growth rate of colonies and of individuals within colonies. Combined analyses of microboring abundance and skeletal density will contribute significantly to our understanding of the biological and environmental factors involved in endolithic activity and coral growth.
Catastrophic death assemblage ofChelomophrynus bayi(Anura, Rhinophrynidae) from the Middle Eocene Wagon Bed Formation of central Wyoming
Authors: Henrici Amy C. , Fiorillo Anthony R. 
Published: August 2016

A unique monospecific bonebed of rhinophrynid anurans was recently discovered in the Wagon Bed Formation (Middle Eocene, Uintan), Hot Springs County, Wyoming. The bonebed occurs on a single bedding plane within a thin sandstone layer. This unit is part of a nearshore facies of a calcium carbonate-rich lake in which the water was warm, shallow, and quiet at the site of the mortality layer.A representative area of this bonebed, approximately 450 square centimeters in size, provides the basis for this taphonomic and paleoecologic study. This area contains approximately 600 bones and at least 19 individuals are represented. Skeletons are nearly completely disarticulated but somewhat associated, bone modification features are absent, a slight preferred orientation of the linear bones is present, and many of the lighter, less dense skeletal elements are underrepresented. Scavengers probably contributed to disarticulation of the skeletons. Bone depletion occurred by a combination of the action of scavengers, weak currents, and the sloughing off of body parts as the carcasses floated. The assemblage was not subjected to extensive winnowing by currents.All of the specimens within this assemblage represent young adults. Because the frogs are all of the same ontogenetic age and the deposit shows no signs of time averaging, the assemblage is interpreted as the result of catastrophic death, possibly by disease, of one age class. Either a population of frogs inhabited the site where the mortality layer formed or the carcasses floated into it.
Multielement reconstructions of Palmatolepis and Polygnathus (Upper Devonian, Famennian) from the Canning Basin, Australia, and Bactrian Mountain, Nevada
Authors: Metzger Ronald A. 
Published: August 2016

Upper Devonian (Famennian) sequences were sampled at two sections in the Canning Basin, Western Australia, and a section at Bactrian Mountain, Nevada, over an interval ranging from the Upper crepida Zone into the Lower marginifera Zone of the standard conodont zonation for the Famennian. Over 30,000 conodont elements have been identified among 43 species and subspecies within six genera. New complete and partial multielement reconstructions are illustrated for: Palmatolepis falcata, P. glabra prima, P. loba, P. minuta minuta, P. perlobata perlobata, P. perlobata maxima, P. quadrantinodosalobata, P. rhomboidea, P. schindewolfi, P. subgracilis, P. wolskae, Polygnathus cf. P. diversus, P. glaber glaber, P. nodocostatus nodocostatus, P. subnormalis, and P. cf. P. triphyllatus. The reconstructions are based on stratigraphic occurrence, detailed morphologic similarities, and a few exceptional low-diversity faunas. Additionally, Palmatolepis adamantea n. sp. is proposed based on the Pa element.A more precise understanding of the taxonomic boundaries of Palmatolepis is achieved through knowledge of the entire apparatus, rather than confined to the Pa elements. Reconstructions presented here provide a more comprehensive understanding of the range of morphologic variation that exists in Palmatolepis, and show that a single generalized elemental plan can be demonstrated for all members of the genus. The differences in the non-Pa elements can thus be used to refine taxonomy and increase understanding of phylogenetic relationships at the specific and subspecific level.
A new Middle Pennsylvanian (Westphalian) amphibian trackway from the Cross Mountain Formation, East Tennessee Cumberlands
Authors: Kohl Martin S. , Bryan Jonathan R. 
Published: August 2016

An amphibian trackway collected in minespoil from the Cross Mountain Formation in the Cumberland Mountains of East Tennessee represents the first known Middle Pennsylvanian (Westphalian) amphibian trackway from the southeastern United States. The tracks are impressed onto the upper surface of a bed of fine-grained, cross-laminated sandstone and siltstone, deposited in an upper delta plain environment.The trackway was made by an amphibian with a long glenoacetabular distance and low pace-angulation. The imprints show five digits on the pes and four on the manus. Average measurements for the trackway are: stride, 8.4 cm; pace angulation, 76.1° (manus), 63.1° (pes); track width, 5.5 cm (manus), 6.7 cm (pes); glenoacetabular distance, 16.7 cm. The manus impression averages 2.8 cm long by 3.1 cm wide, and the pes averages 3.8 cm long by 3.1 cm wide. A tail drag is conspicuous along the entire length of the trackway and has a minimum radius of curvature of 9 mm.The trackway is assigned toMatthewichnus caudifern. ichnosp. on the basis of similarities to published material. The trackmaker was probably a temnospondyl labyrinthodont, considering the size of the animal (thus excluding lepospondyls) and the fact that it had a four-digit manus (thus excluding reptiles and anthracosaurian labyrinthodonts).
Statistical pattern recognition in paleontology using SIMCA-MACUP
Authors: Wei Kuo-Yen 
Published: August 2016

This paper describes a pattern recognition method, Soft Independent Modeling of Class Analogy-Modeling And Classification Using Partial least squares (SIMCA-MACUP), and demonstrates its application to two common paleontological problems—identification and prediction. SIMCA-MACUP performs statistical pattern recognition at four hierarchical levels. At level 1, SIMCA builds disjoint principal component models to characterize multivariate data patterns of several classes. At level 2, new, unknown objects are either classified into one of the classes, or recognized as outliers. At levels 3 and 4, the MACUP method models the relationship between external (dependent) variables and internal (independent) variables, and allows prediction of the values of external variables of new objects which are classified at level 2.The applicability of the SIMCA-MACUP has been demonstrated in a case study of the Pliocene planktic foraminiferal cladeGloboconella.Two morphotypes of the cladeGloborotalia (Globoconella) puncticulataandGloborotalia (Globoconella) inflatawere characterized in a reference sample with SIMCA. Ancestral forms of the two morphotypes were traced through the early phylogenetic history of the clade, resulting in a reconstruction of the branching pattern of the divergence ofG. inflatafromG. puncticulata.The apertural height and apertural width of specimens in the ancestral stocks were then treated as if there were two “external” variables, and predicted using MACUP. The predicted values show slight discrepancy from the observed values. The deviation is size-dependent, indicating a decoupling of the apertural shape from the size of foraminifers during the branching process.