bluuebunny/crossref_metadata_2025_split huggingface dataset:
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.
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.
New Permian representatives of ammonoid superfamilies Marathonitaceae and Cyclolobaceae
Authors: Glenister Brian F. , Furnish W. M. 
Published: August 2016

Familial groupings of two upper Paleozoic superfamilies of Goniatitina, Marathonitaceae and Cyclolobaceae, are reviewed. It is concluded that the Marathonitidae gave rise to the Hyattoceratidae and together constitute the Marathonitaceae. Eohyattoceras n. gen. is the Lower Permian ancestral hyattoceratid, and is represented by two new species, the type, E. gerthi from the Roadian of Timor, and E. leei from the Sakmarian of Nevada. An advanced marathonitid from the Lower Permian (Roadian) of Timor is described as Cardiella martodjojoi n. sp.Two lineages within the exclusively Permian family Cyclolobidae are recognized as the subfamilies Kufengoceratinae and Cyclolobinae. Type designations proposed herein fix usage of Demarezites Ruzhentsev (1955) as referring to ancestral Cyclolobinae, and D. oyensi (Gerth, 1950) and D. lidacensis (de Roever, 1940) are redescribed from the Lower Permian (Roadian) of Timor. The Cyclolobidae are derived from the Vidrioceratidae and together constitute the Cyclolobaceae.
The Llandovery—Wenlock Halysitidae from New Brunswick, Canada
Authors: Young G. A. , Noble J. P. A. 
Published: August 2016

A large collection of Silurian halysitids, mainly from the Limestone Point, La Vieille, and Petit Rocher Formations of northern New Brunswick, includes nine species distributed among Catenipora Lamarck, Halysites Fischer von Waldheim, and Cystihalysites Tchernyshev. One species, Cystihalysites belledunensis, is new, and, of the others, half are previously unknown in the Chaleur Bay region and half have been described before from this area.All species are defined using both qualitative and quantitative data. Statistical analysis of serial sections of a corallum of Cystihalysites belledunensis suggests that any random section of a halysitid will yield quantitative data representative of that colony.Preliminary analysis of the relationships between species distributions and stratigraphy and sedimentary associations suggests strong facies-control on the distribution of the four most abundant species. Both Catenipora simplex (Lambe) and Catenipora micropora (Whitfield) occur mostly in outer shelf facies. Cystihalysites belledunensis n. sp. and Cystihalysites encrustans (Buehler) never occur together, the former being found in predominantly high-energy inner shelf facies and the latter in the outer shelf facies.
Bryozoan astogeny and evolutionary novelties: their role in the origin and systematics of the Ordovician monticuliporid trepostome genus Peronopora
Authors: Hickey David R. 
Published: August 2016

Modifications of primitive astogenetic patterns were central to the origin of bifoliate Peronopora. Outgroup comparison with Prasopora indicates that fundamental events in the former's origin included vertical growth of basal lamina skeleton to form the median lamina and heterochronic modifications of early and later-stage astogeny. Heterochronic modifications of early astogeny included acceleration of budding rates in the ancestrular disc, disc enlargement, and reduction of the basal expansion. Later-stage heterochronic modifications included reduction of zooecial length and width of “endozonal” growth and parallel orientation of cystiphragms about maculae. Also important were “2-D” budding in longitudinal ranges and a unique mode of secondary frond formation. Paedomorphosis resulted in constraints on zoarial form, autozooecial morphology, cystiphragm patterning, and increased colonial integration. Coordination of early and later-stage astogenetic events suggests developmental integration linked to median lamina formation. Heterochronic modifications are inferred to have been products of spatial competition in early astogeny and competitive avoidance and resource exploitation in later astogeny. Restricted biogeographic distribution and characteristics of the ancestrula suggest that the larvae of bifoliate Peronopora were nonplanktotrophic.A shared derived suite of characters including the median lamina unite the bifoliate Peronopora clade. Results of cladistic analyses indicate that bifoliate Peronopora comprise a cohesive, statistically significant clade. Character analysis, phylogenetic results, and the restricted biogeographic distribution of bifoliate species support the hypothesis of a monophyletic bifoliate Peronopora clade of generic rank. The generic concept of Peronopora is revised and limited to bifoliate species.
Trilobites of the Gilmore City Limestone (Mississippian) of Iowa
Authors: Brezinski David K. 
Published: August 2016

Four trilobite species are present in the Gilmore City Limestone (Kinderhookian–Osagean) of Humbolt County, Iowa. The most common trilobite taxa,Perexigupyge hodgesin. gen. and sp. andPerexigupyge gerkin. gen. and sp., make up the greatest percentage of the trilobite population. Two other species are known from fragmentary cranidia and are assigned to the generaRichterellaandProetides.Prior to the description of these forms, the only trilobite previously described or illustrated from the Gilmore City Limestone was a cranidium ofProetides insignis(Winchell) from the type area.The Gilmore City Limestone in Humbolt County, Iowa, represents deposits associated with an oölitic sand-shoal environment, including washover-lobe and back-shoal deposits. Morphologic attributes exhibited by the Gilmore City Limestone trilobites, such as low relief and vaulting to the exoskeleton and subdued surface ornamentation, may have been adaptations that enabled them to inhabit current-swept shoal environments. Conversely, coarsely tuberculate forms may have used the tubercules as a mimic of the surrounding coarse-grained sediment or to strengthen the exoskeleton.
Trilobite malformations and the fossil record of behavioral asymmetry
Authors: Babcock Loren E. 
Published: August 2016

Malformations of trilobites are classified as healed injuries, teratological conditions, and pathological conditions. An improved method of recognizing such malformations combines information about the conditions under which cell injury can occur, the processes by which animal tissues react to injury, and trilobite morphology.Study of healed injuries of polymeroid trilobites shows that injuries attributed to sublethal predation tend to be most commonly preserved on the pleural lobes, the posterior half of the body, and the right side. Statistically significant differences in the number of predation scars between the right and left sides is interpreted as evidence of right-left behavioral asymmetry in some predators of trilobites or the trilobites themselves. Asymmetrical, or lateralized, behavior in present-day animals is one manifestation of handedness, and is usually related to a functional lateralization of the nervous system. Evidence of behavioral lateralization in some Paleozoic predators or prey suggests that those organisms also possessed lateralized nervous systems. Right-left differences in preserved predation scars on trilobites date from the Early Cambrian (OlenellusZone), and are the oldest known evidence of behavioral asymmetry in the fossil record.Other examples of structural or behavioral asymmetry from the fossil record of animals are cited. Lateralization is recognized in representatives of the Arthropoda, Annelida, Bryozoa, Echinodermata, Cnidaria, Mollusca, Chordata, and Conodonta, and in trace fossils.
Paleoecology of hardground encrusting and commensal crinoids, Middle Ordovician, Tennessee
Authors: Guensburg Thomas E. 
Published: August 2016

Aspects of functional morphology are examined and lifestyles proposed for seven exceptionally well-preserved crinoids from the Middle Ordovician Lebanon Limestone, Middle Tennessee. Potential ranges of motion are based on plate shapes, articular surfaces of attachment, and feeding structures. This diverse group of crinoids includes disparid inadunates (Columbicrinus crassusandTryssocrinus endotomitus), a hybocrinid (Hybocrinus bilateralis), reteocrinids (Reteocrinus polkiand R.variabilicaulis), and rhodocrinitid camerates (Archaeocrinus snyderiandGustabilicrinus plektanikaulos). Using attachment structures as the basis, these crinoids can be divided into two groups: encrusters and commensals. Encrusters are the most diverse and include all taxa except the rhodocrinitids. They have a small discoidal holdfast and xenomorphic column. Proxistele-mesisteles were holomeric or pentameric. Flexure potential of this region of the column in disparids was increased by wider ligament gaps at nodal-internodal articulations; in other taxa flexure was enhanced by increasing the frequency of columnals. Short dististeles are polymeric or a plate mosaic. This region functioned as a resilient buffer between the mesistele and holdfast. Columns as a whole had moderate flexure potential. Feeding-structure design was varied, although all butHybocrinus bilateralishad pinnulate or nonpinnulate parabolic filtration fans.Hybocrinus bilateralishad atomous arms arrayed in a bilaterally symmetrical pattern; the symmetry plane was oriented parallel to prevailing currents. Commensals in the Lebanon are the rhodocrinitids. Their attachment structures are characterized by a long distally tapering column terminating in a coil. Densely pinnulate arms formed a well-developed parabolic filtration fan.Encrusters were limited to hardgrounds or skeletal substrata. Commensals were more opportunistic, utilizing a variety of substrates, and they were widespread in Lebanon subenvironments including those with both soft and hard seafloors. Lebanon hardground assemblages are characterized by high diversity, particularly among crinoids and bryozoans. They are strikingly tiered according to elevation above the seafloor (and probably additionally by feeding limitations). This assemblage was the result of longterm coevolution in association with hardgrounds.Ontogenetic development of the column of encrusting crinoids indicates that the evolution of holomeric columnals occurred through a simpler sequence than previously proposed and need not have included gradual alignment of offset pentameres as intermediate steps. Columnals evolved from a poorly organized plate mosaic through a polymeric stage.
Numerical taxonomy of fenestrate bryozoans: evaluation of methodologies and recognition of intraspecific variation
Authors: Holdener E. J. 
Published: August 2016

Species-level taxonomy of fenestrate cryptostome bryozoans has been greatly advanced by a recent study of the fenestrate fauna of the Warsaw Formation (Osage–Meramecian) of the Mississippi Valley; subsequent quantitative analysis placed the earlier research on a sound statistical basis. Reproducibility of these results is tested here, and it is demonstrated that subsequent researchers can duplicate earlier data collection and results. The methodology is then extended in space and time to a second fenestrate faunule (Virgilian of east-central Kansas); morphs within two traditionally defined fenestrate species are successfully distinguished.Lithologic characteristics of the two Virgilian study units suggest differences in depositional environments between the horizons and therefore simple ecophenotypy and intraspecific variation cannot be dismissed. However, chamber dimensions, which provide the most sensitive characters for taxonomic discrimination, change in parallel for the two species, whereas exterior skeletal dimensions, which would presumably respond more readily to microenvironmental fluctuations, vary nonsystematically between populations. These results provide a starting point for the evaluation of morphologic change within fenestrates through stratigraphic and paleoenvironmental sequences. Cumulative data sets spanning long time intervals would allow evaluations of evolutionary histories among members of this important Paleozoic clade.
Demosponges and hexactinellid sponges from the Lower Devonian Ross Formation of west-central Tennessee
Authors: Rigby J. Keith , Clement Craig R. 
Published: August 2016

A fauna of eight taxa of demosponges and hexactinellid sponges has been collected from the Lower Devonian (Lochkovian) Ross Formation, largely out of the upper Birdsong Shale Member in Benton, Decatur, and Perry Counties in west-central Tennessee. The Upper Birdsong Shale (“bryozoan zone”) in which the sponges are most common appears to have been deposited below normal wave base in a quiet marine environment, and represents a terrigenous clastic sediment influx onto a carbonate shelf that had existed in the area from at least the middle Silurian. Benton Quarry in Benton County was the most productive locality for fossil sponges.The new demosponge genera and species Ginkgospongia foliata and Coniculospongia radiata occur with the new species Haplistion lobatum and skeletal mats of fine spicules, along with moderately rare specimens of Hindia sphaeroidalis Duncan. The new hexactinellid genus and species Stiodermiella amanita and Stiodermiella tetragona are characterized by peculiar ornamented papillose, swollen spicules that produce a massive, armored layer on the upper part of the sponge. The latter are associated with the new hexactinellid species Twenhofelella bulbulus, which has relatively normal-appearing hexactines, and with an indeterminate hexactinellid genus, which has spinose hexactines in irregular orientation in a small, platelike fragment. Root tufts of probable hexactine origin also occur.Swollen spicules in Stiodermiella are reminiscent of swollen spicules in the family Stiodermatidae Finks, largely from the Permian of western Texas, but elements of the family are also known from Lower Carboniferous to Permian rocks in Europe and North America.
Paleoautecology and systematic re-evaluation of Camptocrinus alabamensis (Mississippian: Chesterian) from northern Alabama
Authors: Maples Christopher G. , Waters Johnny A. 
Published: August 2016

Camptocrinus alabamensis Strimple and Moore, from the Gasperian (Mississippian: Chesterian) part of the Monteagle Limestone and overlying Bangor Limestone in northern Alabama, is the only species of Camptocrinus known to have more than 10 arms. Camptocrinus alabamensis exhibits morphological features (basals that are taller on their posterior ends than on their anterior ends, flattened primanal, shorter posteriormost secundibrachs on C ray and D ray) indicative of a tightly coiled life position, with most of the stem lying along the sediment. Unlike other coiled crinoids, Camptocrinus alabamensis had a double-folded stem and more than 10 arms, which we interpret to have been compromise solutions to the problems of protection from high current energy and predation pressure coupled with the need to lift the animal into a feeding posture. In addition, C. alabamensis is the only dichocrinid exhibiting highly modified pinnules, which may have been used as rheo/chemosensory organs. Camptocrinus alabamensis was a leeward passive suspension feeder that, in times of danger, could fold in its arms and coil tightly against the sediment.Camptocrinus alabamensis is removed from synonymy with C. cirrifer and the diagnosis of Camptocrinus is modified. Species of the genera Camptocrinus and Neocamptocrinus should be used only for specimens in which calyces are known; therefore, the plethora of stem-species erected over the years should all be assigned to stem genera unless adequate calyx descriptions are available.
The problem of vast numbers of cladodont shark denticles in the Pennsylvanian Excello Shale of Pike County, Indiana
Authors: Zangerl Rainer 
Published: August 2016

While studying X-ray films of new iniopterygians (Subterbranchialia, Chondrichthyes) in the Excello Shale from the Field Museum of Natural History's Bethel Quarry locality in southern Pike County, Indiana, a moderately dense spread of tiny cladodont shark denticles was noticed on the radiographs, confined to micro-horizons of shale about 7.5 mm thick, which also contained the iniopterygians.These denticle spreads, which are entirely unrelated to the iniopterygians, but are seen on X-ray films of most of the chondrichthyan skeletons collected from a sheet of Excello Shale of about 500 m2 in extent, and mostly from two very fossiliferous levels, have an average density of about nine denticles per 1 cm2. Because the chondrichthyan skeletons were collected from all parts of the quarry, it is probable that the denticle spreads in several micro-horizons extended over the entire quarry area and perhaps beyond. The number of denticles in each of the micro-horizons in 500 m2 of shale thus amounts to about 4.6 million.A discussion of the origin of these vast numbers of cladodont denticles, given a variety of taphonomic and depositional constraints, results in the conclusion that these large numbers of denticles could not have resulted from the two species of sharks, Denaea meccaensis and Stethacanthulus longipeniculus, that are members of the burial assemblage and bear dentition teeth indistinguishable from those in the areal spread. Evidence suggesting very rapid deposition of organic muds that produced the characteristic Mecca Quarry type carbonaceous, sheety shales rules out the possibility of accumulation of the denticle spreads over extended periods of time. Because sharks do not possess nearly enough dentition teeth to account for this occurrence, one must entertain the possibility that the denticles are not all dentition teeth, but perhaps for the most part mucous membrane (or even dermal) denticles, though none such are presently known to display cladodont design.
New Late Oligocene to Pleistocene hyaline calcareous unilocular foraminifera from DSDP site 357 (Leg 39) on the Rio Grande Rise, southwest Atlantic Ocean
Authors: Patterson R. Timothy , Burbidge Susan M. 
Published: August 2016

Thirty-two new species of unilocular benthic foraminifera were described from 50 Late Oligocene to Pleistocene samples from DSDP Site 357 (Leg 39) on the Rio Grande Rise in the southwest Atlantic Ocean. These new species make up nearly one-third of the 112 species of unilocular foraminifers identified in the core. Such a high proportion of new taxa is not unexpected as the group has been ignored by most researchers.New taxa described include Lagena praemeridionalis, Lagena rotundocostatina, Exsculptina sicula, Exsculptina umbelliforma Patterson and Cavazza, Favulina prolatella, Favulina quasiperthensis, Galwayella copiosotubula, Galwayella oscula, Galwayella spherula, Homalohedra anastomocostata, Homalohedra goniachrados, Homalohedra gothicofenestella, Homalohedra polykamptarion, Lagnea congestacolla, Lagnea derbiosa, Oolina curvella, Vasicostella lecythella, Vasicostella spinulafunda, Fissurina anapetebasilaris, Fissurina binaroculella, Fissurina favobasella, Fissurina fissuroscula, Fissurina labeona, Lagenosolenia angula, Lagenosolenia penna, Palliolatella anfracta, Palliolatella hadrocheilos, Pseudoolina becella, Pseudoolina oscillum, Parafissurina kladerorhektis, Parafissurina prolatolonga, and Pseudofissurina plastica.The new name, Lagenosolenia incompta, is proposed for Lagena bicarinata (Terquem) var. polita Matthes, 1939.
Late Cretaceous and Tertiary aporrhaid gastropods from the southern rim of the Pacific Ocean
Authors: Zinsmeister William J. , Griffin Miguel 
Published: August 2016

The new subfamily Struthiopterinae is proposed for the aporrhaid gastropods occurring in the Late Cretaceous-early Tertiary Weddellian Province along the southern margin of the Pacific. The following genera are placed within the Struthiopterinae: Struthioptera Finlay and Marwick, 1937; Austroaporrhais n. gen.; and Struthiochenopus n. gen. The temporal and biogeographic distribution of members of Struthiopterinae show a similar pattern to other Southern Hemisphere groups of Late Cretaceous and early Cenozoic molluscs with initial disappearance from the western Australasia of the Weddellian Province by the Paleocene while surviving in Antarctica until the late Eocene and eventually disappearing in southern South America during the early Miocene.Also included in this paper is a reappraisal of the species assignable to these genera from Late Cretaceous and early Tertiary of New Zealand, Antarctica, and southern South America together with the description of five new species. The following new species of the Struthiopterinae are described: Austroaporrhais larseni n. sp., A. stilwelli n. sp., A. dorotensis n. sp., Struthiochenopus antarcticus n. sp., and S. philippii n. sp.