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Nearly continuous carbonate deposition more than 70 million years ago on the Panthalassan buildup is recorded in the Upper Paleozoic limestone blocks and breccias in the Itsukaichi–Ome area, west Tokyo. These blocks and breccias resulted from the collapse of the seamount and tectonic mixing with trench-fill deposits and are contained in the Jurassic accretionary complexes of the Chichibu Terrane. One hundred and five species of Permian foraminifers from 64 localities are distinguished in them, in addition to the previously reported 65 species of Carboniferous ones from 36 localities. These faunas are identical with or comparable to those known from 24 fusulinacean zones among 26 that are distinguished in the Japanese Upper Paleozoic. Neoschwagerinids, and some of schwagerinids and verbeekinids, are very characteristic in the Chichibu faunas of the Panthalassan Province. These Middle Permian fusulinaceans are more closely related faunistically to those of some exotic terranes in the circum-Pacific than of the coeval Akiyoshi faunas and the Kurosegawa faunas of Japan. In relation to the provincialism and endemism of fusulinaceans, and paleo-position and travel history of circum-Pacific terranes, important fusulinaceans in this area are represented by: 1) Acervoschwagerina, a specialized, large-sized, inflated schwagerinid in the Artinskian (Yakhtashian); 2) Parafusulina japonica, a schwagerinid entirely lacking in the Permian terranes of Japan in the upper Wordian (upper Murgabian); 3) many diversified Misellina in the Kungurian (Bolorian) and lower Roadian (lower Kubergandian); and 4) well-traceable Maklaya–Neoschwagerina–Yabeina evolutionary lineage in the upper Roadian to Capitanian (Midian).
Well-preserved earliest Ordovician (early to middle Tremadocian) radiolarian faunas were recovered from carbonate rocks of the Cow Head Group of the Great Northern Peninsula of the island of Newfoundland, Canada. The earliest Ordovician faunal assemblages are from Green Point, Martin Point, Broom Point North and South, and St. Paul's Inlet in Gros Morne National Park. Latest Cambrian faunas were also recovered from Green Point and St. Paul's Inlet, but are extremely low in both abundance and diversity. The radiolarian faunas include five families, 10 genera, and 24 species. Of these, one family Aspiculumidae, one genus, and 19 species are new. The new family and new genus are Aspiculumidae and Aspiculum, respectively. The new species are Pararcheoentactinia? cowheadensis, Aspiculum eccentricum, Aspiculum? angulatum, Parechidnina delicata, P. variospina, Curvechidnina multiramosa, Echidnina conexa, E. laxa, E. semiconexa, E. severedeformis, Echidnina? immanis, Palaeospiculum curvum, P. multifurcatum, P. neofurcatum, P. tetractium, Protoentactinia deformis, P. kozuriana, P. primigena, and P. transformis. The Aspiculumidae is established on the basis of the new genus Aspiculum and on Parechidnina, whose family-level assignments were previously indeterminate. The new family Aspiculumidae is distinguished from the other four families by the absence of the spicule system.
All genera of the earliest Ordovician radiolarian faunas can be placed in the families Aspiculumidae, Archeoentactiniidae, Echidninidae, Palaeospiculumidae, and Protoentactiniidae, as can the genera of the Cambrian radiolarian faunas. However, echidninids from Cambrian faunas are generally characterized by interlocked or fused spicules whose original structure is recognizable, while those from the earliest Ordovician are commonly characterized by fused and/or modified spicules. Also, the very rare protoentactinids of the Late Cambrian are extremely abundant and diverse in the earliest Ordovician faunas described herein. Specimens of the families Palaeospiculumidae and Archaeoentactinidae are less diverse and/or less plentiful in the earliest Ordovician compared to those in Cambrian. The genus Parechidnina, which now belongs to Aspiculumidae, is more plentiful and very diverse in the earliest Ordovician, and, at the same time, lineages of the new genus Aspiculum and a related not-yet-named genus began to evolve.
The detailed biostratigraphic ages of the earliest Ordovician radiolarian faunas were determined mainly by the co-occurring conodonts. The age range of the earliest Ordovician faunas represented extends from the Cordylodus lindstromi Zone through the C. angulatus Zone to the Rossodus manitouensis Zone.
The two new sponges, Diagonodictya crusta n. gen. and sp., a small steeply obconical, dictyospongiid hexactinellid, and Pohlispongia monosphaera n. gen and sp., a spheroidal, single-chambered, monaxonid demosponge—along with several isolated hexactinellid spicules—are described from low-energy, low pH, black shales within the Pennsylvanian Desmoinesian Carbondale Formation from northwestern Illinois, from the Illinois Basin. They are associated with a variety of small fossils, which range from radial and spheroidal to lobate obconical, here identified only as forms A and B, that are possible spore-bearing organs of plants. Some of these latter forms occur as core debris associated with fine hexactine-derived sponge spicules and bivalve? fragments in fecal pellets. The described assemblage may have lived as pelagic organisms in a protected environment and may have been deposited under swamp “flotants” in anoxic shallow water conditions. Alternatively, the assemblage may have lived as part of an open water pelagic biota, ending up in death in anoxic, deeper water environments.
Brachiopods are common in the lower and middle parts of the early Mississippian (Osagean) Vicente Guerrero Formation that is mainly a fine-grained quartz arenite found in the Ciudad Victoria area, Tamaulipas, northeastern México. This shallow marine brachiopod fauna includes several spire-bearers: Lamellosathyris lamellosa, Cleiothyridina cf. tenuilineata, Camarophorella sp., Alispirifer tamaulipensis n. sp., Tylothyris? sp., Torynifer pseudolineatus, Syringothyris cf. typa, Syringothyris? sp., and Punctospirifer sp. Similar assemblages have been found in Osagean rocks of the Santiago Formation, Oaxaca, southeastern México, and in several coeval formations in the USA: Arizona, Arkansas, Illinois, Ohio, and Texas. North American biogeographic affinities are suggested for these Mississippian faunas of northeastern México. These contrast markedly with the Late Silurian situation, where the Tamaulipas material has Old World Realm, rather than North American, biogeographic affinities. This supports the interpretation that northeastern México was an integral part of North America by the Mississippian, but not in the Late Silurian.
A jawed polychaete fauna from the upper 30 m of the Upper Ordovician Sylvan Shale (Richmondian, Ashgill) of Oklahoma is described, based on recovered scolecodonts (polychaete jaws). The fauna includes members of six families: Paulinitidae, Ramphoprionidae, Polychaetaspidae, Atraktoprionidae, Hadoprionidae, and Kalloprionidae. Ten species are identified and one new paulinitid species, Kettnerites (Aeolus) sylvanensis, dominates. The low-abundance and relatively low-diversity Sylvan Shale fauna differs from approximately coeval ones of both Laurentia and Baltica, particularly by its high relative frequency of paulinitids. The scolecodonts are associated with chitinozoans, as well as some enigmatic organic-walled microfossils. Conodonts are extremely rare, with Plectodina tenuis, Amorphognathus sp., and Dapsilodus sp. identified.
Conella, Eurypyrene, and Parametaria are three taxa of columbellid neogastropods native to the Neogene American tropics whose monophyly and relationships have traditionally been confused. The primary objective of this study is to reconstruct the phylogenetic relationships of the tropical American species in these genera, to evaluate their monophyly, and to establish their constituencies. Parsimony-based phylogenetic analysis was used to generate phylogenetic topologies, after which the shortest trees were evaluated to minimize stratigraphic debt using a stratigraphic character added to the data set. The morphologically most parsimonious topologies are well resolved but the main clades are not well supported. Stratocladistic evaluation of the most parsimonious trees resulted in four morphologically and stratigraphically shortest trees. Overall, the resultant trees suggest that Conella and Eurypyrene are monophyletic with minor changes to their traditional constituency, but the resulting trees do not support monophyly or constituency of Parametaria, except in a very restricted sense, or as a paraphyletic group including one or more other traditional genera.
Abundant fossil and modern specimens of the bivalve Panomya collected from Hokkaido, northern Japan, belong to five extant species, including P. norvegica and P. trapezoidis (both no longer present in Japan), and P. beringiana, P. nipponica, and P. ampla for modern specimens. I examine the taxonomy for these species around Japan and also for the extinct P. simotomensis and P. izumo from Japan and discuss the geographic history of Panomya. Panomya originated during the latest Oligocene to middle Miocene in the northeastern Gulf of Alaska. Subsequently, P. simotomensis and P. beringiana appeared in the early to late Miocene of northeastern Asia, while P. izumo and P. trapezoidis appeared in the middle to late Miocene of northeastern Asia and Alaska. Panomya nipponica, P. ampla, and P. norvegica appeared during the Plio–Pleistocene in northern Japan and Bering regions. All extant species evolved in the North Pacific; Panomya trapezoidis and P. norvegica extended their ranges to the North Atlantic in the middle Pliocene and early Pleistocene, respectively, and P. beringiana and P. ampla migrated into the Arctic Ocean in the late Pleistocene to Holocene.
Fossilized argonaut egg cases have been recovered from marine siltstones of the late Miocene exposed around margins of the Los Angeles Basin, California. Low radial ribs on the thin, keelless, planispirally coiled egg cases suggest referring them to Mizuhobaris lepta new species. Occurrence of these egg cases in fine-grained Monterey Formation sediments with mesopelagic fish fossils, nannofossils, and Foraminifera indicate deposition in middle-to-upper bathyal depths. Argonaut egg cases have been described from Tertiary strata in Japan, New Zealand, Sumatra, and Europe, but this is the first report of fossilized argonaut egg cases from the Western Hemisphere.
Secretion of egg cases by argonauts probably developed during the Paleogene as a solution to problems of spawning encountered by octopi as they acquired an epipelagic, open-ocean habitat. Shape and sculpture of the egg cases represent responses to hydrodynamics rather than an inheritance from or copying of ectocochliate cephalopods. The cases may provide the eggs with protection from ultraviolet radiation present in the argonauts' near-surface habitat.
New species of Early Ordovician bivalves and rostroconchs from the northwestern Argentina basin are described. Bivalves include the following species: Cienagomya bidentata new genus and species, Goniophorina tenuicostata, Lipanella purmamarcensis new genus and species, Ucumaropsis lermaensis new genus and species, and Coxiconchia babini new species. Among rostroconchs, Ribeiria pojetai new species is recognized. Cienagomya bidentata (late Tremadoc–early Arenig) may represent a phylogenetic link between the families Intihuarellidae and Cycloconchidae. The new family Lipanellidae is erected to include Lipanella n. gen. Recognition of Ucumaropsis n. gen. in the early Arenig attests to the important radiation of the Anomalodesmata in northwestern Argentina.
Five species of aulacopleurid trilobites occur in rich, silicified trilobite faunas from the Upper Ordovician of Virginia: Harpidella triloba (Hu, 1975a), Strasburgaspis cona (Hu, 1971), and Strasburgaspis? n. sp. A, all from the Turinian Edinburg Formation, Harpidella whittingtoni new species, from the overlying Turinian Oranda Formation, and Harpidella evitti new species, from the Chatfieldian Martinsburg Formation. The species of Harpidella, similar to other sets of congeneric taxa known from the formations, are subtly but pervasively differentiated. In addition to qualitative differentia such as the expression of the eye socle and of pygidial tubercle rows, the species are shown to differ in cranidial and librigenal shape via landmark-based geometric morphometric analysis. The genus Strasburgaspis (type species S. cona) is new. It is assigned to Aulacopleuridae on the basis of its micropygous morphology, but it shares potential apomorphies with Brachymetopidae and could prove to be the most plesiomorphic representative of that family.
The holotype of the ceratopsid dinosaur Torosaurus (=Arrhinoceratops?) utahensis (Gilmore, 1946) consists of a right squamosal, jugal, quadrate, quadratojugal, epijugal, lacrimal, and postorbital horncore/orbital region. Some elements previously described by Gilmore (1946), notably the epoccipitals and parietals, were not originally included, so they cannot be considered part of the holotype. Associated elements (lower jaws and others), which may pertain to the holotype, are described for the first time; they, too, are not formally considered part of the type material, but they provide additional information regarding the osteology of this rare chasmosaurine.
Torosaurus utahensis differs from T. latus (type species) in having a squamosal that is shorter and squared-off at its distal end and an unusually expanded horncore base that lies above and anterior to the orbit. In contrast, T. latus has unusually long, attenuated triangular squamosals and a more restricted horncore base. The otic notch is more open in T. utahensis than T. latus. The genus Torosaurus is distinguished from other chasmosaurine genera by a combination of characters including a broad, thin, sheetlike parietal with relatively small, nearly circular fenestrae and broad median parietal bar; convex posterior margin of parietal; and relatively straight postorbital horncores that are oval (elliptical) in cross section.
Bona fide records of T. latus from Montana, South Dakota, and Wyoming are from strata of Lancian (late Maastrichtian) age. Previous reports of Torosaurus from the Naashoibito Member of the Ojo Alamo Formation (Lehman, 1981, 1985, 1996) in the San Juan Basin and the McRae Formation (Lucas et al., 1998), New Mexico, as well as the single Torosaurus record from Saskatchewan (Tokaryk, 1986), are based on specimens that can at best be identified as Chasmosaurinae genus indeterminate, because they lack derived features of the taxon. Putative Torosaurus specimens from the Big Bend region of Texas (Lawson, 1976; Lehman, 1996) are also considered as indeterminate chasmosaurines. All records of Torosaurus are Maastrichtian in age, but records of T. utahensis appear to be older than those of T. latus.
Burrows of the lysorophid amphibian Brachydectes elongatus occur in deposits interpreted as ephemeral ponds within the Lower Permian Speiser Shale of eastern Kansas. The burrows of B. elongatus have been previously recorded in the Lower Permian strata of Texas, Oklahoma, and Kansas, but have not been described in detail and an ichnotaxonomic designation has not been provided. Torridorefugium eskridgensis new ichnogenus and ichnospecies show two types of burrow architecture distinguished by width-to-length ratios. Type I burrows are elongate, elliptical tubes 4–32 cm long and 2–7 cm wide. Type II burrows are short, elliptical tubes 1.5–3.5 cm long and 2.5–5 cm wide. Both Type I and II burrows may contain coiled skeletons of B. elongatus. Torridorefugium eskridgensis occur in clusters of up to 45 burrows with maximum concentrations of 20/m2.
The type specimens of Torridorefugium eskridgensis occur in a 40-cm-thick lens of calcareous mudstone that fills a 100-m-long paleodepression within a well-developed paleosol. The burrow clusters are capped by surfaces with evidence of subaerial exposure, and overlain by nonburrowed, massive mudstone containing the fossils of the charophyte Stomachara, the ostracodes Carbonita and Paraparchites, fish, amphibians, and reptiles. This succession suggests that lysorophids burrowed in response to episodic, perhaps seasonal, droughts on the Permian midcontinental coastal plain. Permian lysorophid burrowing behavior is analogous to that of the extant aestivating amphibians Amphiuma sp. and Siren intermedia that inhabit ephemeral rivers and ponds of the southeastern United States.