bluuebunny/crossref_metadata_2025_split huggingface dataset:
Origination, survivorship, and extinction of rudist taxa
Authors: Jones Douglas S. , Nicol David 
Published: August 2016

Rudists arose in the Late Jurassic and survived for nearly 100 m.y. before becoming extinct at the end of the Cretaceous. Over this interval they diversified gradually during the Late Jurassic and Early Cretaceous, rapidly in the mid-Cretaceous, then more slowly in the Late Cretaceous. Total rates of origination and extinction during the Late Jurassic and Early Cretaceous were uniform and comparable to those reported for other groups. The Late Cretaceous, however, was characterized by high and widely fluctuating total origination and extinction rates. Per taxon rates reveal a similar pattern except for high and variable rates in the Jurassic. The number of genera increased from the Oxfordian to a peak in the Cenomanian, decreased in the Turonian and Coniacian coinciding with a minor mass extinction event, and rose to a zenith in the Maastrichtian. Unlike other groups investigated, the rudists were at their highest level of diversity immediately prior to their disappearance.Rudist genera survived for a mean of 12 m.y., whereas families survived for a mean of 48 m.y. Survivorship curves for generic cohorts, based upon survival of all rudist genera that evolved during each stage, exhibit a concave shape when the effects of mass extinction and variance at low diversities are considered. Causal factors involved in the final disappearance of the rudists remain unclear; however, their tropical provinciality in the Late Cretaceous contributed to their vulnerability to mass extinction.
Middle Miocene planktonic microfossils and lower bathyal foraminifera from offshore southern California
Authors: Bergen Ted F. W. , Sblendorio-Levy Joanne , Twining John T. , Casey Richard E. 
Published: August 2016

Lower bathyal sediments representing portions of the Luisian and Mohnian stages of Kleinpell (1938) occur on a submarine ridge near Tanner Bank, offshore southern California. The presence of abundant and well-preserved calcareous nannofossils, diatoms, silicoflagellates, radiolarians and foraminifera allows accurate correlations with the onshore type sections of these stages. In terms of the calcareous nannofossil zones, the age range is from theSphenolithus heteromorphusZone to theDiscoaster kugleriZone. Although abundant benthic foraminifera indicative of the Luisian and Mohnian are present, they are accompanied by species more characteristic of the Pliocene Repettian Stage of Natland (1952) and the Pliocene-Miocene “Delmontian” Stage of Kleinpell (1938). Many of these latter species live today at lower bathyal depths (below 2,000 m), others occur in lower bathyal sediments as old as Oligocene, but are absent in the onshore type sections of the Luisian and Mohnian stages in coastal California. We ascribe their absence in onshore sequences to deposition at middle bathyal depths. The known chronostratigraphic ranges of several species are extended and five new species and two new subspecies of benthic foraminifera are described.The following new taxa are described:Bolivina pelitan. sp.,Cassidulinella inflatan. sp.,Globocassidulina undulatan. sp.,Cibicidoides mckannai miocenicusn. subsp.,C. mckannai sigmosuturalisn. subsp.,Pullenia fragilisn. sp.,Parafissurina inornatan. sp.
North American Devonian Carydiidae (Bivalvia): systematics, phylogeny, and implications in early diversification of the class
Authors: Bailey J. Bowman 
Published: August 2016

Although past authors have regarded the Carydiidae as a European family, six species ofCarydiumare reported here from the Devonian of eastern North America. Two of these belong to a single morphocline common in the Hamilton shales; another (Carydium clarkei) is new. Due to lack of well preserved hinges most of these species were earlier placed inNuculabecause serrations or striations on dental elements were mistaken for a taxodont dentition.New data require modification of carydiid phylogenies of earlier authors. 1) Two independent pre-Devonian derivations fromLyrodesmaare inferred. 2)Noradonta shergoldi, a carydiid-like lyrodesmatid from the Ordovician of Australia, is recognized as an important phyletic link between the Carydiidae and the Lyrodesmatidae. 3) The previous view of three distinct lineages withinCarydiumis not supported. Anamorphic data suggest as few as two main lineages and show two of the hinge types to be homeomorphic grades appearing separately or within one or the other of the main lineages.Though too young to be directly involved in the early diversification of the Bivalvia, the actinodont, subheterodont, and pseudotaxodont hinge morphologies ofCarydiumsupply models for the origin of heterodont and taxodont hinges. Anamorphic and other evidence suggests that both are iterative types, and fundamental differences between them may be few. Hence, their preeminence as diagnostic criteria among higher taxa is diminished.
The implications of data base management systems to paleontology: a discussion of Jurassic ammonoid data
Authors: Smith Paul L. 
Published: August 2016

Data from current research dealing with Jurassic ammonoids and stratigraphy of western North America are being stored in a computer file called AMMON using a data base management system. Each ammonite is described by up to 94 descriptors divided into the following six categories: taxonomy, quantitative morphology, qualitative morphology, stratigraphy, locality-catalogue information and general remarks. Data entry is facilitated by the use of a template on a video display terminal, the use of code numbers instead of full names and the bulk entry of hierarchic data. The computer can be used to speed fossil identification and retrieve geologic data by matching lists of descriptor states for a given specimen against those stored in the data bank. By interfacing with statistical analytical systems a ‘profile’ of a given taxon can be generated showing ranges of morphologic variation for any stage of ontogeny. Multivariate techniques are readily employed and subtle patterns of covariation more easily assessed. The data base may also be questioned to instantly generate taxonomic lists by zone, geographic area, lithostratigraphic unit, etc. (or any combination thereof) so that its research potential is considerable.AMMON is a prototype meant to serve as a basis for discussion in developing a globally acceptable ammonoid data base. If code numbers for taxonomic, morphologic and stratigraphic data are standardized, information can be exchanged internationally using magnetic tapes and then decoded by the computer into any language. As data bases proliferate, they will inevitably make paleontological information more readily accessible to the specialist and non-specialist alike.
Early Silurian inadunate crinoids (Brassfield Formation, Ohio)
Authors: Ausich William I. 
Published: August 2016

Eight Early Silurian inadunate crinoids are described. These include: a pisocrinid, genus and species undetermined; (?)Myelodactylus sp.; Kanabinocrinus thyaros n. gen., n. sp.; Euspirocrinus heliktos n. sp.; (?)Euspirocrinus sp.; Eoparisocrinus siluricus n. comb. (n. gen.); Dendrocrinus daytonensis n. sp.; and dendrocrinid, genus and species undetermined. Parisocrinus siluricus, Parisocrinus mulletensis, and Euspirocrinus obconicus are all reassigned to Eoparisocrinus. Parisocrinus is restricted to members of Devonian and Mississippian age. The genus Parisocrinus is discussed, and its type species P. perplexus is illustrated.Pisocrinid, genus and species undetermined, (?)Myelodactylus sp., and Kanabinocrinus thyaros represent the oldest member of the family in which each belongs. The phylogenetic relationships of these and other taxa are discussed.
Lower Middle Devonian Stromatoporoidea from Empire Beach, southern Ontario, Canada
Authors: St. Jean Joseph 
Published: August 2016

Seven species belonging to three stromatoporoid genera are described from two localities at Empire Beach, southern Ontario.Stromatoporellais the most diverse genus, to which five species are assigned. The most common species isSyringodictyon tuberculatum(Nicholson), represented by ten of the twenty-four collected specimens. One genus,Syringodictyon, and one species,Stromatoporella megastrorhizifera, are new.Stromatoporellacf.S. compositaYavorsky is unassigned.The species range in age from Emsian, or possibly Siegenian, to Frasnian. They correlate well with stromatoporoids described from strata equivalent to the lower Detroit River Group, Edgecliff Member (Onondaga Formation), as well as with the Couvinian–Eifelian horizons of Europe.
The distribution and inferred larval dispersion ofRhondellina dorei:a new Cambrian brachiopod (Acrotretida)
Authors: Rowell A. J. 
Published: August 2016

Rhondellina dorein. gen., n. sp. is morphologically a very unusual acrotretid in possessing a marginal ventral beak and vestigial ventral pseudointerarea. In common with all other acrotretaceans it has a pitted first-formed shell that is an evolutionary novelty for the clade. By analogy with developmental stages of living lingulids and discinids it is concluded that these pitted first-formed valves are not protegula, but are larval valves developed during a protracted pelagic phase. The distinction is important in considering dispersal of the organisms. Although some acrotretids are endemic and limited to rocks deposited around a single Cambrian continental landmass, others are cosmopolitan. The wide dispersal of such forms supports earlier conclusions that the functional significance of the pits in the larval valves was an adaptation to increase buoyancy and suggests that the larvae were planktotrophic. Because of energy problems inherent with planktotrophic larvae and small parents, it is conceivable that acrotretacean development was mixed and that a relatively small number of lecithotrophic eggs were brooded prior to release of the free-swimming planktotrophs.Rhondellina doreiwas seemingly endemic to Cambrian North America. Although its larvae apparently were unable to cross oceanic barriers, the species dispersed around the periphery of the craton. It is known from western Utah and eastern Nevada and also occurs in Peary Land, North Greenland, on the opposing side of the continent. In the western United States it occurs only in theCrepicephalusZone (lower Dresbachian, Upper Cambrian), but in Greenland it appears earlier in the upperLejopyge laevigataZone, in beds that are the temporal equivalents of the North AmericanCedariaZone.
Triassic notostracans in the Newark Supergroup, Culpeper Basin, northern Virginia
Authors: Gore Pamela J. W. , Traverse Alfred 
Published: August 2016

Fossilized notostracan carapaces and abdominal fragments are present in the Upper Triassic (Rhaetian) Bull Run Formation in the Culpeper Basin near Manassas, Virginia. Over 250 notostracan carapaces and carapace fragments and three abdominal fragments with attached caudal rami were collected from light olive-gray, grayish-red, and brownish-gray shales in three on-strike localities. Carapace and abdomen are attached in one specimen. The Culpeper Basin notostracans have a rudimentary supra-anal plate and are identified asTriopscf.cancriformis. Their carapaces are indistinguishable from those of modern forms.Relatively few notostracan fossils are known and none have been reported previously from the Triassic of North America. Triassic notostracans, however, have been reported from Europe and Africa. Fossil notostracans have been reported from North America only once previously, from the Permian of Oklahoma.The notostracans are associated with conchostracans(Cyzicussp.), ostracodes(Darwinulasp.), fish scales, insects, plant fragments, and stromatolites.The notostracan-bearing beds are present at the top of a transgressive-regressive sequence, indicating that the notostracans inhabited shallow water near the edge of a perennial lake. Palynology indicates that these beds are most likely mid- to late-Rhaetian in age.
The aulacopleurid trilobite Otarion, with new species from the Silurian of northwestern Canada
Authors: Adrain J. M. , Chatterton B. D. E. 
Published: August 2016

The genus Otarion Zenker, 1833, first appears in the Wenlock simultaneously with Cyphaspis Burmeister, 1843, as the oldest known species of each occur together in the southern Mackenzie Mountains of the Canadian Northwest Territories. The genera are unambiguous sister groups, a relationship supported most compellingly by a uniquely derived and distinctive pattern of juvenile cephalic spines, shared also with the Carboniferous genus Namuropyge Richter and Richter, 1939. This sister group relationship permits the development of a robust and stratigraphically correlated hypothesis of relationship among the adequately known species of Otarion, Otarion, Cyphaspis, and Namuropyge constitute the tribe Otarionini. The Mississippian genus Dixiphopyge Brezinski, 1988, may also belong to Otarionini. Namuropyge is a paedomorph, likely derived from a Degree Six or Seven meraspid of an older species of uncertain position in the Otarion–Cyphaspis clade.Three Wenlock species of Otarion occur in stratigraphic succession in a single section in the Mackenzie Mountains. Analysis of morphological change with time, and of sequential ontogenies, suggests that the Silurian history of the genus was dominated by incidents of peramorphosis.New species are Otarion huddyi, O. beukeboomi, and O. coppinsensis. Otarion brauni Perry and Chatterton, 1979, is revised.
On the taxonomic status of Cycnorhamphus and Gallodactylus (Pterosauria: Pterodactyloidea)
Authors: Bennett S. Christopher 
Published: August 2016

One of the rarest pterosaurs from the Upper Jurassic Solnhofen Limestone of southern Germany is Pterodactylus suevicus. Only two specimens are known: the holotype, consisting of a virtually complete skeleton described by Quenstedt (1855); and a second specimen, consisting of only postcranial elements described by Wagner (1858) and lost during World War II (Wellnhofer, 1970). Seeley (1870) noted that P. suevicus differed from P. antiquus, the type species of Pterodactylus, in a number of significant points. Therefore, he placed P. suevicus in a new genus, Cycnorhamphus. Seeley (1870:111) gave the following diagnosis of Cycnorhamphus:“Nares very small, looking upward from a swan-like beak. The middle hole of the skull very large and elongated and lateral. Neck long. Wing-metacarpal long. Four joints in wing-finger. Ilium widening in front. Epipubic bones meeting mesially. The type is Pterodactylus suevicus (Quenstedt).”The character “nares very small” was the result of a misinterpretation of depressions on the premaxillae that probably resulted from crushing, and “middle hole of the skull” referred to the confluent naris and antorbital fenestra, which Seeley apparently considered the antorbital fenestra alone.
Cambrian–Ordovician boundary interval extinctions: implications of revised trilobite and brachiopod data from Mount Wilson, Alberta, Canada
Authors: Loch James D. , Stitt James H. , Derby James R. 
Published: August 2016

The type section of the Basal Silty Member of the Survey Peak Formation spans the Cambrian–Ordovician boundary (North American usage) at Mount Wilson in the southern Canadian Rocky Mountains. The zonal and subzonal terminology through the boundary interval developed in Texas and Oklahoma is applicable to the trilobite faunas recovered from the section. The oldest trilobites recovered in this study occur in the top of the underlying Mistaya Formation and are assigned to theSaukiella serotinaSubzone of the Upper CambrianSaukiaZone. Trilobites and brachiopods of theS. serotinaandEurekia apopsisSubzones of theSaukiaZone occur in the lower half of the Basal Silty Member; trilobites and brachiopods assigned to the Lower OrdovicianMissisquoiaZone and theSymphysurina brevispicataSubzone of theSymphysurinaZone occur in the upper half of the Basal Silty Member. TheS. brevispicataSubzone extends an unknown distance into the Putty Shale Member of the Survey Peak Formation.The extinction horizons at the base of theEurekia apopsisSubzone and at the base of theMissisquoia depressaSubzone (the Cambrian–Ordovician boundary) occur within the Basal Silty Member of the Survey Peak Formation, not at the formational contact with the underlying Mistaya Formation. This leaves hypotheses linking immigration of the replacement trilobite faunas to major lithofacies changes through the boundary interval as untenable. Critical review of the evidence for the extinctions at the end of the Ptychaspid Biomere suggests that they were caused by an invasion of the shelf region by cold, anoxic water.Forty-seven taxa are illustrated and 18 of those which provide new taxonomic information are discussed. One new genus,RampartaspisLoch, is described in addition to four new species:Eurekia plectocanthusLoch,Highgatella wilsoniDerby,Macronoda punctataDerby, andRampartaspis dissimulosulcusLoch. The identifications of trilobites and brachiopods in this paper revise those of Aitken and Norford (1967) and Derby et al. (1972) and result in minor changes in the reported positions of the bases of theMissisquoiaandSymphysurinaZones. Revision of the identification of some trilobites in Dean (1989) changes the biostratigraphic interpretation of the Basal Silty Member at Wilcox Pass, Albert, Canada.
Crinoids from the Upper Ashgill (Upper Ordovician) of Wales
Authors: Donovan Stephen K. , Veltkamp Cornelis J. 
Published: August 2016

A collection of small crinoids and crinoid debris from the Ashgill (Rawtheyan?) of Cnwce, near St. Clears, Dyfed, southwest Wales includes numerous crowns ofAithriocrinus strahanin. gen. and sp. incertae familiae, an indeterminate 10–armed camerate(?) and an indeterminate multiple-armed camerate.Aithriocrinus strahaniwas previously considered to be a cincinnaticrinid, but it is undoubtedly dicyclic and therefore a cladid. This is the only diverse fauna of complete crinoids known from the Welsh Ashgill.The monobathrid camerateXenocrinusS. A. Miller is easily recognized from its disarticulated columnals, which are square in outline.Xenocrinuscolumnals are now recognized from three Hirnantian localities in Wales.Xenocrinusbecame extinct during the Hirnantian and not at the Rawtheyan–Hirnantian boundary, as has been suggested on the basis of crown material.
Advanced cladid crinoids from the middle Mississippian of the east-central United States: intermediate-grade calyces
Authors: Kammer Thomas W. , Ausich William I. 
Published: August 2016

Species of the late Osagean and early Meramecian advanced cladid crinoid genera (suborder Poteriocrinina) Abrotocrinus, Aulocrinus, Cromyocrinus. Decadocrinus, Dinotocrinus, Holcocrinus, Hylodecrinus, Lanecrinus n. gen., Pachylocrinus, Parascytalocrinus n. gen., and Stinocrinus from Illinois, Indiana, Iowa, Kentucky, and Missouri are redescribed and redefined from study of type material and museum collections. Nomenclatural and systematic acts include the following: 1) Abrotocrinus cymosus Miller and Gurley, 1890a, is a valid species and not a synonym of A. coreyi (Meek and Worthen, 1869); 2) A. coreyi is a senior synonym of Poteriocrinus orestes Worthen, 1882; 3) Scaphiocrinus manus Miller and Gurley, 1890a, is assigned to Abrotocrinus; 4) Abrotocrinus granulatus n. sp. is described; 5) S. bellus Miller and Gurley, 1890a, is assigned to Aulocrinus and is a senior synonym of Aulocrinus agassizi Wachsmuth and Springer, 1897; 6) S. orbicularis Hall, 1861a, is assigned to Cromyocrinus; 7) P. latidactylus Worthen, 1882, is assigned to Dinotocrinus; 8) S. gibsoni White, 1878, is assigned to Hylodecrinus with P. nauvooensis Worthen, 1882, questionably placed in synonymy; 9) P. briareus Worthen, 1882, is assigned to Hylodecrinus and is a senior synonym of S. lacunosus Miller and Gurley, 1890a, S. boonvillensis Miller, 1891b, S. constrictus Miller, 1891a, and S. arrosus Miller and Gurley, 1893; 10) S. bonoensis Miller and Gurley, 1890a, is assigned to Hylodecrinus; 11) Hylodecrinus robustus n. sp. is described; 12) P. validus Worthen, 1882, is questionably assigned to Hylodecrinus; 13) Lanecrinus n. gen. is described and the following species are assigned to this new genus: S. halli Hall, 1861 a, S. depressus Meek and Worthen, 1870, P. milleri Wetherby, 1881, P. fountainensis Worthen, 1882, S. repertus Miller and Gurley, 1890a, and Ramulocrinus consectatus Strimple and Watkins, 1969; P. otterensis Worthen, 1882, is questionably assigned to Lanecrinus; 14) Lanecrinus depressus is the senior synonym of P. ulrichi Worthen in Miller, 1889, and S. maniformis Miller, 1892; 15) Lanecrinus repertus is the senior synonym of S. gorbyi Miller, 1891a; 16) P. asper Worthen, 1882, is assigned to Pachylocrinus and is a senior synonym of S. extensus Wachsmuth and Springer, 1886; 17) Parascytalocrinus n. gen. is described and the following species are assigned to this new genus: Poteriocrinus hamiltonensis Worthen, 1882, and Scytalocrinus validus Wachsmuth and Springer, 1897; 18) Poteriocrinites mcadamsi Meek and Worthen, 1873, is questionably placed in synonymy with Parascytalocrinus hamiltonensis; and 19) Poteriocrinus burketi Worthen, 1882, nomen dubium and Zeacrinus dubius Miller and Gurley, 1890a, are placed in Incertae Sedis.Cromyocrinus orbicularis is the oldest species of its genus extending the range of the genus downward from the Upper to the Lower Mississippian.
Conodont biostratigraphy and depositional history of strata comprising the Niagaran sequence (Silurian) in the northern part of the Cincinnati Arch region, west-central Ohio, and evolution ofKockelella walliseri(Helfrich)
Authors: Kleffner Mark A. 
Published: August 2016

The Dayton, Osgood, and Laurel Formations and the Euphemia, Springfield, and basal part of the Cedarville Dolomites near the axis of the Cincinnati Arch in northeast Preble County, Ohio, belong in the uppermost part of theOzarkodina sagitta rhenanato lower part of theOzarkodina?crassaChronozone and are late early to middle Wenlockian in age. The Dayton–Cedarville succession on the eastern flank of the Cincinnati Arch in north-central Greene County, Ohio, belongs in the uppermost part of thePterospathodus cellonito upper part of theAncoradella ploeckensisChronozone and is late Llandoverian to early middle Ludlovian in age.The sea transgressed across the exposed and eroded Brassfield Formation to begin deposition of the Dayton Formation on the eastern flank of the Cincinnati Arch in Greene County, Ohio, during the late Llandoverian and completely flooded all of west-central Ohio by the late early Wenlockian. The region remained covered by a sea of fluctuating depth during deposition of the Dayton Formation–Cedarville Dolomite succession from the Wenlockian through early middle Ludlovian.Kockelella walliseri(Helfrich) evolved fromK. ranuliformis(Walliser) during the middle Wenlockian (upper part ofOzarkodina sagitta rhenanaChronozone) by development of a lateral process adjacent to the cusp on the Pa element and by minor modification of the Pb element and some of the ramiform elements. Specimens from upper Llandoverian and lower Wenlockian strata previously assigned toK. walliseribelong to a different species,Kockelellasp. A Fordham, 1991. The evolutionary trends in theK. walliserilineage, progressive restriction of the basal cavity and increasing development of the length of the lateral processes in the Pa element, parallel the trends in theK. amsdeni–K. stauros–K. variabilislineage and resulted in the divergence ofKockelellacf.K. staurosBischoff, 1986, from the main lineage in the middle Wenlockian.