Showing papers in "Journal of Paleontology in 1988"
TL;DR: A proper appreciation of trends as changes in variance flows from and into the two most important revisionary themes in modem evolutionary theory: constraint and structure as an antidote to overreliance upon adaptation and hierarchy.
Abstract: Trends are the primary phenomenon of macroevolution, but they have often been misinterpreted because an old and deep conceptual error has induced us to misread, as anagenesis in abstracted entities, a pattern that actually records changes in variance by increase or decrease in diversity or disparity among species within clades. These patterns are actually produced by the “entity making and breaking machine” of differential species success, but we misread history as anagenesis because we focus on extreme values (though they may only represent tails in variance of a system), or on measures of central tendency that shift passively as species birth and death work in their differential way. I discuss several examples in two classes: “increase trends” mediated by growth in variance, and “decrease trends” produced by diminution of diversity or disparity. I present two examples in extenso based on original data: threefold occurrence of Cope's rule in planktonic foraminifers as a consequence of increasing species diversity from small founding lineages (increase trend), and disappearance of 400 hitting in baseball as a decrease trend recording symmetrical decline of variance with increasing excellence of play, not the gradual extinction of a valued “thing.” A proper appreciation of trends as changes in variance flows from and into the two most important revisionary themes in modern evolutionary theory: 1) constraint and structure as an antidote to overreliance upon adaptation (questions about why founding lineages tend to be small, and why size ranges are constrained, lie primarily in structural, not adaptational, domains); 2) hierarchy (increase and decrease trends are powered by differential species sorting, not by extrapolated anagenesis of competition among organisms within populations).
264 citations
TL;DR: In this article, six species of Platycrinites and one species of Eucladocrinus are considered valid in the Keokuk Limestone through St. Louis Limestone of the stratotype area.
Abstract: Late Osagean to Meramecian Platycrinites and Eucladocrinus from Illinois, Iowa, and Missouri are redescribed and redefined from study of type material. Three of the oldest species were incorrectly synonymized with P. sarae, and this correction leads to a realignment of species systematics within Platycrinites. Accordingly, six species of Platycrinites and one species of Eucladocrinus are considered valid in the Keokuk Limestone through St. Louis Limestone of the stratotype area. Valid species include Platycrinites saffordi (Hall), P. sarae (Hall), P. georgii (Hall), P. pumilus (Hall), P. brevinodus (Hall), P. niotensis (Meek and Worthen), and Eucladocrinus millebrachiatus Wahsmuth and Springer. Nomenclatoral changes include the following: 1) P. sarae is redescribed and all junior synonyms are removed; 2) P. georgii is a valid senior synonym of P. bonoensis (White), P. aeternalis (Miller), P. boonvillensis (Miller), and P. cauducus; 3) P. pentagonus (Miller) is a junior synonym of P. niotensis; 4) P. pumilus is a valid senior synonym of P. prattenanus (Meek and Worthen), and P. monroensis (Worthen); 5) P. bloomfieldensis (Miller) is designated as a nomen dubium; and 6) Eucladocrinus millebrachiatus immaturus is a junior synonym of E. millebrachiatus.The evoluton of new species in Platycrinites was by a combination of cladogenesis and possibly anagenesis. Platycrinites sarae evolved from P. saffordi possibly through anagenesis, P. pumilus evolved from P. niotensis through cladogenesis, and P. hemisphaericus evolved through cladogenesis from P. brevinodus, although P. hemisphaericus does not occur in the geographic area of this study.
188 citations
TL;DR: Protochthonius gilboa n. gen. and sp. is the earliest derivative known member of the Enarthronota, and comprises the monobasic new family Protochthoniidae as mentioned in this paper.
Abstract: Fourteen oribatid mite fossils have been recovered from a terrestrial Devonian deposit near Gilboa, New York; they allow an approximate doubling of the known age of the group. Two species are represented by specimens complete enough to allow descriptions. Protochthonius gilboa n. gen. and sp. is the earliest derivative known member of the Enarthronota, and comprises the monobasic new family Protochthoniidae. Devonacarus sellnicki n. gen. and sp. also represents a monobasic new family, Devonacaridae; it may also be an early derivative enarthronote mite, but its relationships are uncertain. Two other species are represented at the site, but meaningful descriptions are not possible with available material.
144 citations
TL;DR: The binomial distribution was used by Dryden (1931), Dennison and Hay (1967), Wright and Hay as discussed by the authors, and Patterson and Fishbein (1989) for this purpose.
Abstract: In paleontological investigations the number of individuals of a particular species, ni, is often expressed as a proportion of the total number of individuals, ∑i=1S ni = n, for all, S, species. This proportion, p = ni/n expressed in percent, is referred to by various authors as percent species, relative abundance, percentage abundance, species frequency, fractional abundance, and so on. Naturally, researchers are interested in the confidence limits that can be placed on these estimates, and in the number of individuals required to obtain them. The binomial distribution was used by Dryden (1931), Dennison and Hay (1967), Wright and Hay (1971), and Patterson and Fishbein (1989) for this purpose.
143 citations
TL;DR: There is strong morphological evidence, supported by the stratigraphic distribution of species, that Retroceramus cf.
Abstract: Extensive collections from stratigraphically controlled sections allow reassessment and systematic revision of Middle Jurassic inoceramids from Argentina. Two species are doubtfully referred to Parainoceramus Voronetz, including P.? westermanni n. sp. Five species of Retroceramus Koshelkina, including R. cf. R. marwicki (Speden), R. patagonicus (Philippi) and R. stehni n. sp., are present. The Bajocian-early Callovian species of Retroceramus show strong affinities with Aalenian-Bathonian inoceramids from the Northern Hemisphere, and also with the South Pacific forms of the galoi-haasti group of Heterian-Ohauan age, except for minor differences in outline, ornamentation, and the umbonal region. The time range of each species in Argentina was determined by associated ammonoids. There is strong morphological evidence, supported by the stratigraphic distribution of species, that Retroceramus cf. R. marwicki, R. patagonicus, and R. stehni belong to a single clade, which developed from the late Bajocian to the early Callovian in the Andean region.
140 citations
TL;DR: The Spring Canyon Member of the Blackhawk Formation is divisible into four regressive hemicycles of deposition, each representing the downdip part of a nearshore-to-offshore sequence as discussed by the authors.
Abstract: ABSTRAcr-In Coal Creek Canyon, Utah, the Spring Canyon Member of the Blackhawk Formation is divisible into four regressive hemicycles of deposition, each representing the downdip part of a nearshore-to-offshore sequence. The first and fourth hemicycles are best developed. Individual bedding units span middle-shoreface to lower-offshore lithofacies, the latter corresponding to a thin intertongue of Mancos Shale. Trace fossil assemblages include ~22 ichnospecies and 17 ichnogenera: Ancorichnus, Aulichnites, Chondrites, Cylindrichnus, Ophiomorpha, Palaeophycus, Phoebichnus, Planolites, Rosselia, Schaubcylindrichnus, Scolicia, Skolithos, Taenidium, Teichichnus, Terebellina, Thalassinoides, and Uchirites. Diversity and abundance of ichnospecies are greater in nearshore than in offshore lithofacies. Distal deposits are typified by obscure bioturbate textures: Cylindrichnus concentricus, Palaeophycus heberti, and Rosselia socialis are prevalent through the remainder of the lithofacies suite. Ophiomorpha irregulaire and Schaubcylindrichnus coronus are most common in middle-shoreface beds and Chondrites ichnosp. in upper-offshore beds; Ophiomorpha nodosa and O. annulata also are common in this part of the sequence.
135 citations
TL;DR: The Upper Proterozoic euendolithic assemblage closely resembles a community of euENDolithic cyanobacteria found today in shallow marine ooid sands of the Bahama Banks.
Abstract: Silicified oolites and pisolites from Bed 18 of the Upper Proterozoic (about 700-800 Ma) Limestone-Dolomite "Series" of the Eleonore Bay Group, central East Greenland, contain a diverse suite of organically preserved microfossils that is, for the most part. [Of the] assemblages previously described from Proterozoic cherts and shales. Three principal assemblages occur in these rocks: 1) a class bound assemblage found in detrital carbonate grains (now silicified) that served as nuclei for ooid and pisoid growth, as well as in uncoated mud and mat clasts that were carried into the zone of ooid and pisoid deposition; 2) an epilithic and interstitial assemblage consisting of microorganisms that occurred on top of and between grains; and 3) a euendolithic assemblage composed of microbes that actively bored into coated grains. The Upper Proterozoic euendolithic assemblage closely resembles a community of euendolithic cyanobacteria found today in shallow marine ooid sands of the Bahama Banks. Thirteen species are described, of which eight are new, five representing new genera: Eohyella dichotoma n. sp., Eohyella endoatracta n. sp., Eohyella rectoclada n. sp., Thylacocausticus globorum n. gen. and sp., Cunicularius halleri n. gen. and sp., Graviglomus incrustus n. gen. and sp., Perulagranum obovatum n. gen. and sp., and Parenchymodiscus endolithicus n. gen. and sp.
93 citations
TL;DR: In this paper, a Campanian fish assemblage is described from the uppermost Blufftown Formation in western Georgia, and 15 chondrichthyan and eight osteichthyan taxa are identified, virtually all for the first time from the region.
Abstract: A Campanian fish assemblage is described from the uppermost Blufftown Formation in western Georgia. Fifteen chondrichthyan and eight osteichthyan taxa are identified, virtually all for the first time from the region. The study area represented a transitional zone between the Atlantic and eastern Gulf of Mexico Coastal Plain Provinces during the Late Cretaceous, and shows faunal relationships with both. marginal and epicontinental marine strata; the thick, de- trital sediments in the lower Chattahoochee River Valley of the Georgia-Alabama region are not exceptional in this regard. Nevertheless, the regional literature pays scant attention to Cre- taceous fish fossils. Recent work reported here has yielded an unusually diverse and abundant assemblage of cartilaginous and bony fish represented by teeth and other materials from the uppermost few meters of the Blufftown Formation, mid-to-late Campanian age, in western Georgia. Work is in progress by the authors on another regional fossil fish assemblage, that of the Eutaw Formation (locally of probable mid-Santonian age). PREVIOUS REGIONAL STUDY
75 citations
TL;DR: The Cretaceous Kodiak Formation at the northeastern end of Kodiak Island, Alaska, is interpreted to have been deposited in a distal deep-sea fan complex.
Abstract: The Cretaceous Kodiak Formation at the northeastern end of Kodiak Island, Alaska, is interpreted to have been deposited in a distal deep-sea fan complex. Facies analysis of the sequence suggests deposition in channels (both major and distributary), lobe fringe (proximal and distal), and interchannel and interchannel/channel mouth environments. The strata contain a diverse and relatively abundant trace fossil assemblage consisting, at the ichnogeneric level, of twenty-six forms: Acanthorhaphe, Chondrites, Circulichnis, Cochlichnus, Cosmorhaphe, Desmograpton, Glockerichnus, Gordia, Helminthoida, Helminthopsis, Muensteria, Neo- nereites, Nereites, Paleodictyon, Palaeophycus, ?Phycosiphon, Planolites, Protopaleodictyon, Scolicia, Spirophycus, Spirorhaphe, Tae- nidium, Taphrhelminthopsis, Terebellina, Thalassinoides, and Yakutatia. Thirty-eight ichnospecies are described, three of which (Acanthorhaphe ichnosp., Cosmorhaphe helicoidea, and Desmograpton fuchsi) are recorded for the first time in North America. Final channel-fill (levee) and interchannel environments contain the most abundant and diverse ichnoassemblages, a reflection of favorable environmental parameters for inhabitation by benthic organisms, but more importantly the presence of diverse lithotypes conducive to the final preservation of their activity. Channel-fill sequences are devoid of trace fossils, a reflection of substrate mobility and lack of shale interbeds precluding toponomic preservation. Lobe fringe sequences contain only isolated trace fossils, a reflection of their poor exposure and largely monolithologic character. The ichnoassemblage is compared to 20 previously described and taxonomically well-documented deep-water flysch trace fossil studies from the Phanerozoic. Comparison at the ichnogeneric level is favorable with only Acanthorhaphe, Terebellina, and Yakutatia being relatively unique to the Kodiak sequence.
72 citations
60 citations
TL;DR: Palmer et al. as mentioned in this paper found that borers are very common in a variety of hard substrates in these rocks, including skeletons of bryozoans, corals, and stromatoporoids, as well as cobbles and hardgrounds.
Abstract: Although the burrows and trails in the Upper Ordovician rocks around Cincinnati, Ohio, have been fully documented and are well known (Osgood, 1970), comparatively little attention has been paid to the borers. Nevertheless, borers are very common in a variety of hard substrates in these rocks. These substrates include the skeletons of bryozoans, corals, and stromatoporoids (Palmer and Wilson, 1988), as well as cobbles and hardgrounds (Palmer, 1982; Wilson, 1985). By far the most common type of boring is the elongate tube Trypanites, which could have been made by a variety of filter-feeding worms. Trypanites is common on hard substrates throughout the lower Paleozoic (Palmer, 1982).
TL;DR: Foraminifer assemblages from the Siuransky Horizon at the base of the Bashkirian is essentially identical to that from the top of the underlying Lower Carboniferous Serpukhovian Stage.
Abstract: The stratotype for the Bashkirian Stage of the Soviet Middle Carboniferous is located on the Askyn River in Gornaya Bashkiria (western slope of south Urals). Twenty-four rock samples, mostly from the lower part of the section, yielded abundant and diverse assemblages of calcareous foraminifers which are systematically described and illustrated here for the first time. The foraminiferal assemblage from the Siuransky Horizon at the base of the Bashkirian is essentially identical to that from the top of the underlying Lower Carboniferous Serpukhovian Stage. Thus, foraminifers do not provide a basis for identifying the Soviet Lower???Middle Carboniferous boundary. This notwithstanding, the presence of the foraminifer Globivalvulina bulloides (Brady) (=G. moderata Reitlinger) and the conodont Idiognathodus parvus (Dunn) in both the upper Serpukhovian and Bashkirian indicates that the base of the Bashkirian can be no older than medial to late Morrowan of the North American succession. The primitive fusulinid Pseudostaffella (Pseudostaffella) appears at the bases of the lower Bashkirian Akavassky Horizon and the North American Atokan Series. The base of the Akavassky is interpreted to be somewhat older than early Atokan, however, because Ps. (Pseudostaffella) appeared in the Urals in phylogenetic continuity with its immediate ancestor, whereas in most of North America it was an immigrant. The type Bashkirian succession contains a seemingly complete phylogeny from advanced eostaffellids to primitive fusulinids. Plectostaffella jakhensis, immediate ancestor to the fusulinids, arose from a member of the Eostaffella postmosquensis plexus in the late Serpukhovian. Plectostaffella jakhensis, in turn, gave rise to Ps. (Semistaffella) variabilis in the early Bashkirian (late Siuransky), from which evolved Ps. (Ps.) antiqua shortly thereafter (earliest Akavassky). An as yet unidentified but advanced species of Ps. (Pseudostaffella) is the most likely ancestor to late Bashkirian Neostaffella ivanovi. The evolutionary series leading from the E. postmosquensis plexus to primitive Neostaffella apparently developed exclusively in the Eurasian???Arctic faunal realm, as Pl. jakhensis, Ps. (Semistaffella) variabilis, and Ps. (Ps.) antiqua are unknown in the Midcontinent???Andean region. Diverse Ps. (Pseudostaffella) spp. appeared in the latter area pursuant to an adaptive radiation aided by periodic interchange between faunal realms.
TL;DR: The Oligocene-Miocene Bluff Formation of Grand Cayman Island contains casts of Entobia (nine species including E. dendritica), Trypanites (three species), Gastrochaenolites (two species), Maeandropolydora (one species), Talpina, and Caulostrepsis as mentioned in this paper.
Abstract: Molds of corals, bivalves, and gastropods in the Oligocene–Miocene Bluff Formation of Grand Cayman Island contain casts of Entobia (nine ichnospecies including the new ichnospecies E. dendritica), Trypanites (three ichnospecies), Gastrochaenolites (two ichnospecies), Maeandropolydora (one ichnospecies), Talpina (one ichnospecies), and Caulostrepsis (one ichnospecies), as well as the new ichnogenus Uniglobites, indeterminate ichnogenus A, and a problematical boring. Entobia accounts for about 75 percent of the borings, while Uniglobites and Trypanites together account for 15 percent of the borings. Comparison of Uniglobites with modern borings of known affinity suggests that it was produced by adociid and/or clionid sponges while indeterminate ichnogenus A was probably formed by bivalves. The amount of boring, which ranges from 0 to 75 percent, varies from skeleton to skeleton or, in some cases, from branch to branch of the same coral colony. The branching coral Stylophora was particularly susceptible to boring, probably because of its small size and high surface area. The average boring of about 38 percent compares favorably with the amount of boring found in modern corals. Analysis of the borings suggests that sponges were responsible for most of the borings in the corals from the Bluff Formation. Comparison with bioerosion in modern reefs suggests that similar patterns of bioerosion were also occurring in Oligocene–Miocene times.
TL;DR: The premise that derived similarities in early ontogeny reflect proximity of common ancestry provides a framework for evaluating relationships within the trilobite subfamily Encrinurinae Angelin and allied taxa on the basis of larval characters to corroborate a hypothesis of distant common ancestry and early divergence of this clade.
Abstract: r-The premise that derived similarities in early ontogeny reflect proximity of common ancestry provides a framework for evaluating relationships within the trilobite subfamily Encrinurinae Angelin and allied taxa on the basis of larval characters Protaspides for eight species of Ordovician and Silurian encrinurines are compared through cladistic analysis of character distributions; these are assigned to Encrinuroides Reed, Cromus? Barrande, Balizoma Holloway, and a new genus of the Encrinurus variolaris plexus Llandeilo Encrinuroides insularis Shaw, in which two metrically and morphologically distinct protaspid stages (instars) are rec- ognized, provides a standard for comparisons This two-stage division of the protaspid period is a synapomorphy of early encrinurines (Ordovician Encrinuroides), advanced cybelines (several species of Cybeloides Slocom), and early staurocephalids (Libertella Hu) The former groups further share a subtrapezoidal-subquadrate stage 1 instar with a single pair of protopygidial marginal spines, while stage 2 is broader with three pairs of marginal spines The two-stage protaspis in this clade, associated with several other evolutionary novelties (a torulus, prominent glabellar tubercle pairs, fixigenal "circumocular tubercles"), marks a reduction from the plesiomorphic state of numerous calcified larval instars (including small early "anaprotaspides") in pliomerids and early cybelines The conventional paraphyletic constructs of the Cybelinae and Encrinuroides obscure patterns of nested synapomorphy indicated by larval and adult character states Protaspides of Silurian Balizoma spp record a further shift in timing of calcification, with reduction to a single large instar with ontogenetically advanced character states (possibly allometric correlates of size increase) indicating homology with stage 2 of Encrinuroides and advanced cybelines Profound differences between protaspides of Llandovery Cromus? n sp (the first known for this genus) and those of other encrinurines corroborate a hypothesis of distant common ancestry and early divergence of this clade
TL;DR: Sodium metatungstate (SMT), 3Na2WO4 · 9WO3 · H2O, is a nontoxic, high-density (1.00-3.10 g/cm3) separating compound which results in nearly neutral (pH 6) solutions of relatively low viscosity as discussed by the authors.
Abstract: Sodium metatungstate (SMT), 3Na2WO4 · 9WO3 · H2O, is a nontoxic (Sax, 1979), high-density (1.00-3.10 g/cm3) separating compound which results in nearly neutral (pH 6) solutions of relatively low viscosity. It was presented as a medium for density gradient centrifugation by Plewinsky and Kamp (1984). Since then, investigators have used SMT (or sodium polytungstate) as a high-density medium for routine mineral separations, for recovery of conodonts from insoluble residues, for separation of various feldspar species from one another, and for segregation of inorganic mineral fractions (ash) from coal.
TL;DR: Glaessner et al. as mentioned in this paper described eight brachyuran decapod crustaceans from coastal outcrops of Island Sandstone between Perpendicular Point and Punakaiki, Westland, New Zealand.
Abstract: Eight species of brachyuran decapod crustaceans are recorded from coastal outcrops of Island Sandstone between Perpendicular Point and Punakaiki, Westland, New Zealand. The fauna consists of three raninids— Laeviranina pororariensis (Glaessner), L. keyesi n. sp., Lyreidus bennetti n. sp.; two portunids— Rhachiosoma granuliferum (Glaessner), Pororaria eocenica Glaessner; a goneplacid— Carcinoplax temikoensis n. sp.; and two majids— Leptomithrax griffini n. sp., Notomithrax allani n. sp. Together, they form the most diverse brachyuran assemblage yet described from New Zealand. The decapods are preserved in unusual elliptical masses, with their long axes typically parallel to bedding, containing superbly preserved cuticle often surrounded by well-formed fecal pellets, probably of decapod origin. The accumulations are interpreted to be mechanical concentrations within depressions produced by decapods or associated spatangoid echinoids. Although seven of the species have been recorded only from the Island Sandstone, Rhachiosoma granuliferum (Glaessner) is now known to occur in the correlative deep-water facies of the Kaiata Formation in North Westland, as well as in the Tapui Sandstone, North Otago (middle Eocene), and from coeval rocks at Snowdrift Quarry, southeast Otago. The raninids suggest comparison with congeneric forms from Snowdrift Quarry and the Tapui Sandstone, as well as with the La Meseta Formation, Seymour Island, Antarctica. Based upon associated foraminiferans, a Kaiatan–Runangan (late Eocene) age is assigned to this fauna. The occurrences of Carcinoplax, Leptomithrax , and Notomithrax represent paleobiogeographic and stratigraphic records for the genera.
TL;DR: Nematothallus Lang (N taenia, N lobata, and N elliptica) was described from a coaly lens in the Bloomsburg Formation (Ludlow).
Abstract: The early terrestrial fossil record contains numerous Siluro-Devonian problematic Thallophyta which have morphological and habitat characteristics intermediate between the algae and the embryophytic plant kingdom Three new species of the genus Nematothallus Lang (N taenia, N lobata, and N elliptica) are described from a coaly lens in the Bloomsburg Formation (Ludlow) They are included in the order Nematophytales, which is placed in a new informal taxonomic group, Paraphyta, intended to include enigmatic, terrestrial plant-like fossils These species designations are based upon the gross morphology of carbonized thalli which consist of an underlying anatomy of flattened tubular elements The association and attachment of cuticles and axes of ?Prototaxites to Nematothallus is clearly demonstrated in these collections The morphological and anatomical variety expressed in the numerous fragments of thalli from the deposit implies moderate levels of organic diversity in a “flora” of nonvascular, terrestrial plant-like thallophytes which predates the adaptive radiation of the embryophytes
TL;DR: In this paper, a Q-mode multidimensional scaling analysis of ichnogenera from Caldwell and Alta defines an environmental gradient, where tracefossil assemblages dominated by deposit-feeders in lower energy facies grade to ethologically diverse assemblage in higher-energy facies.
Abstract: fair-weather conditions. Marine-deltaic facies in an ever-shallowing, coarsening-upward transition overlie a transgressive shale lithofacies younger than the Sunbury. Upsection, prodelta, shoreface, bar-washover, and foreshore-beach facies contain a diverse assemblage of Bifungites, Helminthopsis, Monocraterion, Palaeophycus, Phycodes, Planolites, Rosselia, Rusophycus, Scalarituba, and Skolithos. Interdistributary bay shales contain Helminthopsis and Scalarituba deposit-feeding traces. Distributary mouth-bar deposits contain Monocraterion and Skolithos suspension-feeding traces in sandstone, and Helminthopsis, Planolites, and Scalarituba deposit-feeding traces in shale interbeds deposited under slack-water conditions. Hummocky cross-stratified sandstones, wave-rippled siltstones, and silty shales from inner shelf facies at Alta contain an ethologically diverse Cruziana Ichnofacies consisting of Arenicolites, Bifungites, Chondrites, Cruziana, Dolopichnus, Helminthopsis, Monocraterion, Phycodes, Planolites, Rosselia, Skolithos, Sustergichnus, Teichichnus, and Zoophycos. Zoophycos occurs abundantly only in sandstones containing phosphate pebble lags that represent a transgression, when dysaerobic bottom water may have temporarily encroached onto normally aerobic inner shelf facies. A Q-mode multidimensional scaling analysis of ichnogenera from Caldwell and Alta defines an environmental gradient. Tracefossil assemblages dominated by deposit-feeders in lower energy facies grade to ethologically diverse assemblages in higher energy facies. Low-energy facies are represented by shaly lithologies deposited in deeper water, or in shallow but protected environments.
TL;DR: Two new species of worm tubes referable to the genus Onuphionella occur in Lower Cambrian strata in eastern California and western Nevada, indicating that correlations between the two regions are not greatly in error.
Abstract: Two new species of worm tubes referable to the genus Onuphionella occur in Lower Cambrian strata in eastern California and western Nevada. Onuphionella durhami n. sp. is found in the Campito Formation (in pre-trilobite strata, in the Fallotaspis and, possibly, the Nevadella Zones) and O. claytonensis n. sp. occurs in the Middle Member of the Poleta Formation (Nevadella Zone). The unusual tubes are armored with an imbricated coat of mica flakes, reminiscent of the modern genus Owenia. The lowest occurrence of Onuphionella in western North America corresponds closely with the lowest occurrence of the genus in the Baltic region, indicating that correlations between the two regions are not greatly in error.
TL;DR: The distinctive trace fossil Chubutolithes gaimanensis n. ichnosp n. occurs in Casamayoran (early Eocene) and Colhuehaupian (late Oligocene) alluvial rocks of the Sarmiento Formation as discussed by the authors.
Abstract: The distinctive trace fossil Chubutolithes gaimanensis n. ichnosp. occurs in Casamayoran (early Eocene) and Colhuehaupian (late Oligocene) alluvial rocks of the Sarmiento Formation in eastern Chubut Province, Argentina. Though known for nearly 70 years, its origin has remained obscure. Examination of new specimens and comparisons with modern analogs demonstrate that specimens of Chubutolithes represent the fossil nests of a mud-dauber (Hymenoptera: Sphecidae). Virtually identical nests are constructed today by mud-daubers in areas as disparate as southern Santa Cruz Province, Argentina, and Nebraska, confirming that quite similar trace fossils can be produced by several different taxa in a higher taxonomic clade. No satisfactory ethological term exists for trace fossils that, like Chubutolithes, were constructed by organisms above, rather than within, a substrate or medium. The new term aedificichnia is proposed.Chubutolithes occurs in alluvial paleosols and is associated with a large terrestrial ichnofauna. These trace fossils include the nests of scarab beetles, compound nests of social insects, and burrows of earthworms.
TL;DR: The name Chubutolithes was proposed by Ihering (1922) for an unknown type of fossil occurring in Eocene continental rocks of Patagonia, Argentina as mentioned in this paper.
Abstract: The name Chubutolithes was proposed by Ihering (1922) for an unknown type of fossil occurring in Eocene continental rocks of Patagonia, Argentina. Bown and Ratcliffe (1988) demonstrated that Chubutolithes is a trace fossil; specifically, it is the fossil nest of a mud-dauber. The latter authors also suggested that Chubutolithes was constructed by an insect belonging to the hymenopteran family Sphecidae, and coined the specific name C. gaimanensis for the unusual trace fossil. Comparison with a Recent nest of the mud-dauber Auplopus (Pompilidae; Figure 1.1) suggests that Auplopus is a much more likely candidate as the architect of Chubutolithes than are any sphecid mud-daubers.
TL;DR: In the Late Ordovician Cliefden Caves Limestone Group in central-western New South Wales, Australia, the conodonts suggest a middle to late Caradocian (mid-Shermanian to mid-Edenian) age as mentioned in this paper.
Abstract: New species of Aphelognathus, Belodina, Taoqupognathus, and Yaoxianognathus have been identified in the Late Ordovician Cliefden Caves Limestone Group in central-western New South Wales, Australia. Of the Aphelognathus species, Aphelognathus percivali n. sp. and A. webbyi n. sp. occur in the basal Gleesons Limestone Member and A. packhami n. sp. and A. stevensi n. sp. occur 30 m higher in the Wyoming Limestone Member. It seems likely from the similarity of several of the elements that A. packhami is closely related to A. percivali, and A. stevensi to A. webbyi. Yaoxianognathus wrighti n. sp. occurs in the Gleesons Limestone Member but not in the Wyoming Limestone Member. Belodina confluens, Belodina hillae n. sp., Belodina n. sp., Panderodus gracilis, Taoqupognathus philipi n. sp., and Phragmodus? tunguskaensis occur at both horizons. The conodonts suggest a middle to late Caradocian (mid-Shermanian to mid-Edenian) age for the lowest part of the Cliefden Caves Limestone. The occurrence in southeastern Australia of the forms Taoqupognathus, Yaoxianognathus, and Phragmodus? tunguskaensis suggest affinities to coeval faunas in China and eastern Siberia. The four new species of Aphelognathus are distinct from known species in the Late Ordovician of North America and Europe but they may help characterize a paleobiogeographic region that includes eastern Australia and southeast Asia.
TL;DR: In this article, the authors describe the fish taxa from the Simpson Park Range section at Coal Canyon, central Nevada, including thelodont scales of the family Nikoliviidae; heterostracan scales; acanthodian scales, platelets, and spines of Nostolepis type, Gomphonchus type, Acanthodes type, Machaeracanthus type, and climatiid type; placoderm scales of buchanosteid and radotinid types.
Abstract: Vertebrate microfossils as minor constituents of acid-etched limestone residues in the Lochkovian (Lower Devonian). This paper describes the fish taxa from the Simpson Park Range section at Coal Canyon, central Nevada. These include thelodont scales of the family Nikoliviidae; heterostracan scales; acanthodian scales, platelets, and spines of Nostolepis type, Gomphonchus type, Acanthodes type, Machaeracanthus type, and climatiid type; placoderm scales of buchanosteid and radotinid types; and the shark, Polymerolepis whitei.
TL;DR: Cheetham and Deboo as discussed by the authors suggested the use of the range-through method (i.e., a species is considered present in a sample if found both above and below it, even if it was not found within the sample) as a means of smoothing these spotty data sets and, when biostratigraphic conclusions are sought, to counteract the effect of environmental influences.
Abstract: THE QUALITY of the information yielded by stratigraphic and paleoecologic studies based on microfossils is often poor due to spotty recovery of taxa. Thus, downcore sequences contain many null records between the first appearance (FA) and the last appearance (LA) of the species. Cheetham and Deboo (1963) suggested the use of the range-through method (i.e., a species is considered present in a sample if found both above and below it, even if it was not found within the sample) as a means of smoothing these spotty data sets and, when biostratigraphic conclusions are sought, to counteract the effect of environmental influences (Hazel, 1970). The technique was subsequently adopted in many reports and incorporated in numerical methods for biostratigraphic work (e.g., see review in Brower, 1985). This procedure, however, has a distorting effect on the data in such a way that faunal similarities between the samples compared are artificially increased toward the middle of the column. This is due to the fact that, while in the original species x samples array the probability of filling any cell is mainly a function of the species' abundance and of the number of specimens scanned in that particular sample, in the matrix resulting from the range-through principle it also depends upon the number of samples checked both above and below the level in question. Since the number of these samples is highest for the central part of the sequence and decreases toward the top and bottom, the central section will have artificially enhanced specific co-occurrences and, hence, faunal similarities. This distortion is subsequently reflected in the results attained after processing the
TL;DR: Eighteen species of Hyolithes and one species of Orthotheca from the Appalachian region and Western Interior were reexamined in light of more modern taxonomic concepts and standards of quality for type material.
Abstract: Concepts of the family Hyolithidae Nicholson fide Fisher and the genera Hyolithes Eichwald and Orthotheca Novak have been expanded through time to encompass a variety of morphologically dissimilar shells. The Hyolithidae is here considered to include only those hyolithid species which have a rounded (convex) dorsum; slopes on the dorsum are inflated, and the venter may be flat or slightly inflated. Hyolithes encompasses species which possess a low dorsum and a prominent longitudinal sulcus along each edge of the dorsum; the ligula is short and the apertural rim is flared. The emended concept of Orthotheca includes only those species of orthothecid hyoliths which have a subtriangular transverse outline and longitudinal lirae covering the shell on both dorsum and venter. Eighteen species of Hyolithes and one species of Orthotheca from the Appalachian region and Western Interior were reexamined in light of more modern taxonomic concepts and standards of quality for type material. Reexamination of type specimens of H. similis Walcott from the Lower Cambrian of Newfoundland, H. whitei Resser from the Lower Cambrian of Nevada, H. billingsi Walcott from the Lower Cambrian of Nevada, H. gallatinensis Resser from the Upper Cambrian of Wyoming, and H. partitus Resser from the Middle Cambrian of Alabama indicates that none of these species represents Hyolithes. Hyolithes similis is here included under the new genus Similotheca, in the new family Similothecidae. Hyolithes whitei is designated as the type species of the new genus Nevadotheca, to which H. billingsi may also belong. Hyolithes gallatinensis is referred to Burithes Missarzhevsky with question, and H. partitus may represent Joachimilites Marek. The type or types of H. attenuatus Walcott, H. cecrops Walcott, H. comptus Howell, H. cowanensis Resser, H. curticei Resser, H. idahoensis Resser, H. prolixus Resser, H. resseri Howell, H. shaleri Walcott, H. terranovicus Walcott, and H. wanneri Resser and Howell lack shells and/or other taxonomically important features such as a complete aperture, rendering the diagnoses of these species incomplete. Their names should only be used for the type specimens until better preserved topotypes become available for study. Morphology of the types of H.? corrugatus Walcott and "Orthotheca" sola Resser does not support placement in the Hyolitha; the affinities of these species are uncertain.
TL;DR: In this paper, a well-preserved and potentially diverse Lower Permian ammonoid fauna from south-central Thailand has been discovered, which is similar to the one described in this paper.
Abstract: The purpose of the present statement is to announce discovery of a well-preserved and potentially diverse Lower Permian ammonoid fauna from south-central Thailand. Previous Thai records of Permian ammonoids lack descriptive detail (e.g., Yanagida, 1988), but two sparse Permian occurrences from nearby areas in Malaysia have been described recently by Lee (1980). Closest similarities of the Thai material are with faunas from the Pamir (Leonova and Dmitriev, 1989) and with our undescribed collections from south Xinjiang.
TL;DR: In this paper, it was shown that even high metabolic rate dinosaurs probably remained in their polar habitats year round and had avian-mammalian metabolic systems, and may have borne insulation at least seasonally, severely limits their use as polar paleoclimatic and Earth axial tilt indicators.
Abstract: The presence of Late Cretaceous social dinosaurs in polar regions confronted them with winter conditions of extended dark, coolness, breezes, and precipitation that could best be coped with via an endothermic homeothermic physiology of at least the tenrec level. This is true whether the dinosaurs stayed year round in the polar regime-which in North America extended from Alaska south to Montana-or if they migrated away from polar winters. More reptilian physiologies fail to meet the demands of such winters in certain key ways, a point tentatively confirmed by the apparent failure of giant Late Cretaceous phobosuchid crocodilians to dwell north of Montana. Low metabolisms were also insufficient for extended annual migrations away from and towards the poles. It is shown that even high metabolic rate dinosaurs probably remained in their polar habitats year round. The possibility that dinosaurs had avian-mammalian metabolic systems, and may have borne insulation at least seasonally, severely limits their use as polar paleoclimatic and Earth axial tilt indicators. Polar dinosaurs may have been a center of dinosaur evolution. The possible ability of polar dinosaurs to cope with conditions of cool and dark challenges theories that a gradual temperature decline, or a sudden, meteoritic or volcanic induced collapse in temperature and sunlight, destroyed the dinosaurs.
TL;DR: Character analysis, phylogenetic results, and the restricted biogeographic distribution of bifoliate species support the hypothesis of a monophyletic b ifoliate Peronopora clade of generic rank.
Abstract: 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.