World Realm Research Articles

Semitubina yukonensis new species, first occurrence of this biogeographically distinctive Old World Realm gastropod genus in the Lower Devonian of the western hemisphere

Despite the rapidly expanding knowledge of Lower Devonian brachiopod faunas of the Western Cordillera of Canada (Lenz, 1976, 1977a, 1977b, 1982; Ludvigsen, 1970; Perry, 1984; Perry and Lenz, 1978; Perry et al., 1974, 1981), equivalent data on coeval gastropod faunas from this region are non-existent; to date, no publications have appeared in which gastropods have been described. Blodgett et al. (1988, table 1) provided faunal lists for two Lower Devonian localities in Western Canada: 1) Lochkovian-Emsian age collections from the Mackenzie Mountains, Northwest Territories, collected by the late D. G. Perry as part of his Ph.D. dissertation (Perry, 1984); and 2) an early Emsian collection from the Mt. Lloyd George area, British Columbia. We are currently examining the gastropod material recovered by A. C. Lenz from his richly diverse collections in the Royal Creek area, Yukon Territory, equivalent in age to those gathered by D. G. Perry from the Mackenzie Mountains. This note is the first of several papers focused on these paleobiogeographically significant faunas, and it is our desire to ultimately make clear the character of this Early Devonian province, which appears to include strata of British Columbia, Yukon and Northwest Territories, as well as the non-accreted portion of adjacent east-central Alaska.

Rugose coral diversifications and migrations in the Devonian of Australasia

The occurrence of approximately 100 rugose coral genera has been confirmed in the Devonian carbonate dominated successions of Australasia. Their temporal distribution shows that the largest faunal turnovers were in the Pragian and Givetian, with profound extinction events at or near the ends of the Emsian, Givetian and Frasnian. The evolutionary innovation and diversification of the Early Devonian rugose corals of eastern Australia are characterized by a high turnover rate in the late Lochkovian—Pragian and strong dynamism of radiation from late Pragian to medial Emsian, implying considerable dispersal to South China, central Asia and Europe. After a high intensity of origination in the Pragian, maximum diversity was reached in the Emsian. Phillipsastreids and endophyllids appeared late in the Pragian and became common in the Emsian; stringophyllids appeared in the Emsian. As elements of these families are recorded mainly from the Middle, or even Upper Devonian of other provinces of the Old World Realm, it appears that they may have originated in eastern Australia during the Early Devonian. Following a marked decrease in generic richness in the Eifelian, faunal diversity reached another high peak in the early mid‐Givetian as a result of immigration of coral genera, probably from South China, central Asia, Europe and northwestern Canada in the Old World Realm.

Palaeobiogeography of Australian Devonian gastropods

Australian gastropod faunas of Devonian age have received comparatively little attention. The occurrences of key gastropod taxa in the Devonian of Australia are reviewed. High levels of endemism of species in the Early Devonian are overprinted by Old World affinities at the generic and familial levels. These affinities persist into the Givetian, where strong links are maintained with European taxa. Limited data are available for Lochkovian, Eifelian and all Late Devonian gastropod faunas, making assessment of their biogeography difficult. Platyceratids, although present throughout Australia, form a lesser element of the faunas here than in other Old World Realm regions during the Devonian.

A Middle Devonian Trilobite Assemblage from Venezuela

Three new species of trilobites are described from the upper level of the Caño del Oeste Formation (Middle Devonian) of Venezuela. These taxa include a phacopinine, Viaphacops venezuelensis, n. sp., and two asteropyginines, Rhenops odremani, n. sp., and Greenops perijaensis, n. sp. The biogeographic implications of these records are discussed. Viaphacops is somewhat cosmopolitan in its distribution. The presence of Rhenops in Venezuela represents a profound range extension beyond the Rhenish-Bohemia region of the Old World Realm. The Venezuelan occurrence of Greenops represents a southerly range extension within the Eastern Americas Realm, reinforcing faunal similarities previously recognized among Devonian brachiopods and trilobites of Venezuela and North America.

Early Devonian brachiopods from Satun Province, southern Thailand

Twelve brachiopod taxa are described from the Early Devonian (probable early Emsian) Pa Samed Formation of southern Thailand, including the new genus and species Quasiprosserella samedensis (Ambocoeliidae?) and the new species Plectodonta forteyi, Caplinoplia thailandensis, and Clorinda wongwanichi. They are the first undoubted Devonian brachiopods from Thailand. They represent the deeper-water Benthic Assemblages BA4-5, and, although clearly indicative of the Old World Realm, cannot be assigned to a particular biogeographical region. A new undescribed fauna from the contemporary Zebingyi Formation of Burma (Myanmar) is also noted.

Lower Devonian (Emsian) rugosa of the Izarne Formation, Montagne Noire, France

An account of the systematics, biostratigraphy, ecological setting and the biogeographic implications of rugose corals from olistoliths of the Cabrières area is given. Corals of the lower member of the Izarne Formation are dated by conodonts asgronbergiZone age, and includeLythophyllumsp. indet.,Calceola sandalina(Linné),Tryplasmasp. A,Breviphrentis rohartiPedder new species,B. exiguaPedder new species, andAqishaphyllumsp. A. Corals from the middle member of the formation includeFrechocystis pertinaxPedder new genus and species,Calceolasp. undet.,Rhizophyllumsp. aff.R. ukalundenseHill and Jell,Tryplasma enormePedder new species,Tryplasmasp. A,Breviphrentissp. A,Platysmatophyllum halleriPedder new genus and species,Pseudochonophyllum sentumPedder new species, andIzarneophyllum barroisi(Frech) new genus. No age significant conodont has been recovered from the middle member. However, scutelluid trilobites, which, together with other trilobites, evidently used the underside of Izarne corals for shelter during molting, provide correlation with conodont sequences in the nappe domain to the north and southwest of Cabrières. From this line of evidence, the middle Izarne coral fauna is deduced to benothoperbonusZone age. The association of a variety of benthic trilobites, all with large eyes, provides evidence of a photic zone environment for the middle Izarne corals.Rugose corals from the Izarne Formation belong to the Old World Realm and have nothing in common with similar age Rugosa of the Eastern Americas Realm. This implies that the dissolution of the boundary between these realms, which occurred in the Middle Devonian, did not begin before latest Emsian time.

Biostratigraphie et paléobiogéographie du Siluro-Dévonien de la zone de Meguma (Nouvelle-Écosse, Canada)

Studies of fossils collected from the Nictaux–Torbrook and Bear River synclines (Nova Scotia) allow a reexamination of the Siluro-Devonian stratigraphy of the Meguma terrane. The location of this terrane relative to the main paleocontinents of the circumatlantic domain during this period is discussed. Wenlockian, Ludlovian, and Pridolian biostratigraphic horizons have been dated. The benthic fauna of the Torbrook Formation are assigned here to the Lochkovian, Pragian, and Lower Emsian. The Pridolian fauna shows northern European affinities. Thus, the Meguma terrane probably belonged to the North Atlantic domain, as for the Avalon terrane, and occupied a southern position in the "Euramerica" plate during this period. The Devonian fauna belongs to the "old world realm" and shows north Gondwanian and Rhenish affinities. As early as the Lochkovian, species known from both the Rhenish and north Gondwanian domains are recognized in Meguma, as well as others reported so far only from northwestern Africa, Iberian Peninsula, and (or) Armorican Massif. The presence of Rhenish fauna confirms the postulated location for the Meguma terrane during the Upper Silurian since this fauna is representative of southern Baltica marginal areas in Europe. On the other hand, the presence of north Gondwanian fauna implies close relationships with western European margin of Gondwana. The lack of a wide oceanic gap separating north Gondwana and Euramerica can explain the faunal exchanges during Lower Devonian times between western Europe and easternmost Appalachian province despite the presence of a physical barrier.

Spine asymmetry in chonetoidean brachiopods: an example of reiterated heterochronies linked to intra-Devonian events

Abstract From the Early Devonian, the distribution of spines along the posterior margin of the ventral valve of chonetoidean brachiopods, previously symmetrical on each side of the beak during the Silurian, exhibits asymmetrical examples. The asymmetry of spines affects mainly two families which are widely distributed in the Old World Realm during the Devonian: strophochonetids and anopliids. The detailed vertical range of asymmetrical forms, compared with conodont zones, suggests close relationships with Lower and Middle intra-Devonian events. The geographic distribution of the asymmetrical taxa indicates that they mainly characterize the intertropical zones. The development of spine asymmetry is interpreted herein as an innovation and a progenetic heterochrony linked to the onset of a pioneer strategy with an epiplanktonic mode of life. The spine asymmetry is repetitive and a consequence of the intra-Devonian events which contributed to the expression of diversity among chonetoidean brachiopods.

A unique occurrence ofEndophyllum(rugose coral; Devonian) in eastern North America: An ecological and biogeographical puzzle

Endophyllumis described for the first time from North America. The occurrence of a single, large colony in Middle Devonian strata in New York is both biogeographically and environmentally anomalous: it belongs to an Old World Realm genus but was found in the Eastern Americas Realm, and it occurred in a gray, ambocoeliid-bearing mudstone, a facies in which morphologically complex corals are otherwise unknown. Available evidence suggests that the coral lived not far from where it was found, possibly on a hardground or bank a few km north of the outcrop.Endophyllum ciurcainew species is described.

Devonian brachiopods from northern Chile

Fossiliferous marine Devonian has been known in Chile for less than a decade. The initial discovery from south of the Salar de Atacama region, in the Sierra de Almeida, northern Chile is described together with its brachiopods. The brachiopods indicate an age span of Emsian–Eifelian or Givetian, shallow-water conditions in the Benthic Assemblage 2 range, and a biogeographic boundary region between the cool climate Malvinokaffric Realm and warmer region extra-Malvinokaffric Realms, including the Eastern Americas Realm and the Rhenish-Bohemian Region of the Old World Realm. The recent discovery of a Malvinokaffric Realm trilobite far to the south in Chile, at Buill in the Andes of Chiloe, serves to underline our very preliminary knowledge of the Chilean Devonian, whereas the alleged Devonian brachiopods from the Chonos Archipelago far to the south are probably bivalves of uncertain age.

Early and Middle Devonian gastropod biogeography

Abstract Early and Middle Devonian gastropods show biogeographic patterns remarkably similar to those of better studied faunal groups of this same interval, notably articulate brachiopods, rugose corals, and trilobites. Three biogeographic realms are recognized: Old World, Eastern Americas, and Malvinokaffric Realms. Gastropod diversity is highest in the Old World Realm and lowest in the Malvinokaffric Realm. The diversity patterns and the high degree of shell ornamentation suggest that the Old World Realm was generally warmer than the Eastern Americas Realm, and that both were considerably warmer than the cool temperate to cold polar waters of the Malvinokaffric Realm. The utility of gastropods for fine-scale delineation of biogeographic units is illustrated for the Eifelian of western North America. At least two subprovincial units (the Alaska-Yukon and Nevada subprovinces) can be recognized. Eifelian gastropods from interior and southeastern Alaska belong to a single unit (the Alaska-Yukon Subprovince), and are most closely related to coeval faunas of northwestern Canada, suggesting little displacement of most of Alaska's so-called 'suspect' terranes. Plotting the data on the Devonian palaeogeographic maps of Scotese results in several suggested emendations: (1) North America should be moved south by 10-20°; (2) Australia is too far south on the Emsian and Givetian reconstructions, it should be in a more palaeotropical position; and (3) Siberia is too far north, it too should also be placed in a palaeotropical position.

The biogeographic affinities of East Asian corals

Abstract In East Asia the oldest tabulate and rugose corals appeared in the Early and Middle Ordovician. All rugose corals and most tabulate corals appear to have become extinct at the end of the Permian. The Ordovician corals of North China were most closely related to the Americo-Siberian region, but those of South China occupied an independent province. The Silurian corals of Junggar, Hinggan, Mongolia, Altai and Tuva are genera characteristic of the Uralian-Cordilleran region. The South China fauna had a close affinity to that of the East Australia in the Early Silurian, but was more akin to that of the Urals and Central Asia in the Middle and Late Silurian. During the Early and Middle Devonian, there were 5 biogeographic provinces in East Asia, all belonging to the Old World Realm: (1) Arctic province; (2) Junggar-Hinggan province; (3) Uralo-Tian Shan province; (4) Palaeotethyan province and (5) South Chin province. In East Asia, two distinctive zoogeographic provinces are fairly clearly defined: a southern province, with occurrence of Kueichouphyllum and a northern province with occurrences of Gangamophyllum during the Early Carboniferous. In addition, during the Early Permian, a Uralo-Arctic province was dominated by Durhaminidae and a Tethyan province by Waagenophyllidae.

The Balkhash-Mongolia-Okhotsk region of the Old World Realm (Devonian)

Abstract Reconsideration of the Emsian brachiopods from parts of central Asia extending from the Lake Balkhash Region easterly through Heilungjiang leads us to conclude that they should be separated as a distinct region, termed the Balkhash--Mongolia--Okhotsk Region, of the Old World Realm. This conclusion was arrived at after considering the high level of endemic genera, plus the significant admixture of genera common with the Eastern Americas and Tasman Realms.

Two new Devonian spine-bearing pleurotomariacean gastropod genera from Alaska

Two new spine-bearing gastropods,Chlupacispira spinosan. gen. and sp. andSpinulrichospira cheeneetnukensisn. gen. and sp., are described from the late Early Devonian (Emsian) and early Middle Devonian (Eifelian), respectively, of west-central Alaska. These represent the earliest reported spiny pleurotomariacean gastropods. Otherwise, spinose pleurotomariaceans are known from strata no older than Carboniferous age.Spinulrichospira cheeneetnukensisn. gen. and sp. appears to represent a more highly ornamented derivative ofUlrichospiraDonald. Both new genera are part of the more highly ornamented fauna which occurred in warm equatorial waters of the Old World Realm during the Early and Middle Devonian, in contrast to more weakly ornamented shells of the Eastern Americas Realm and even more weakly ornamented (almost totally “plain”) shells of the Malvinokaffric Realm. The latter two realms are thought to represent subtropical to warm temperate and cool temperate to cool polar conditions, respectively.

Revision of Lower Devonian (Emsian) brachiopod biostratigraphy and biogeography, central Nevada

A diverse, previously unknown fauna with Skenidioides and other small brachiopods, ostracodes, trilobites, and corals has been dated as gronbergi Zone on coexisting conodonts. Conodonts date the Leptocoelina globosa fauna as serotinus Zone. Cymostrophia seca, Strophodonta luxor, and Atrypa kobar are new species. These assignments and new occurrences allow retabulation of most Emsian brachiopod ranges in Nevada.Plotting of provincial, endemic, and cosmopolitan brachiopod genera on a time vs. percent graph shows that the shift through time of Nevada faunas from Eastern Americas Realm to Old World Realm took place gradually during Emsian transgression. Endemic genera were prominent during early phases of Devonian transgression.

Brachiopod Community Paleoecology, Paleobiogeography, and Depositional Topography of Devonian Onondaga Limestone in Eastern North America: ABSTRACT

The lower Middle Devonian Onondaga Limestone was deposited in a northwest-southeast elongated topographic basin and on the surrounding carbonate platform. Two sedimentary cycles are present in the Onondaga. The Edgecliff represents a transgression which spread epeiric seas over much of eastern North America. During the Nedrow-Lucas regression, the interior of the platform became restricted resulting in the deposition of evaporites. The Moorehouse transgression continued through the deposition of the Tioga Bentonite, followed by pre-Speeds-Dundee regression from the craton. Onondaga brachiopod communities, arranged from nearshore to offshore, include the Atrypid-Megakozlowskiella, Atrypid-Levenea, Chonetid, Atlanticocoelia, Ambocoeliid, and Truncalosia communities. The Onondaga-age Eastern Americas Realm is divided into the Appohimchi province in the Appalachian basin and the Michigan basin-Hudson Bay Lowland province in the midwest. The provincial assignment of the James Bay region of Ontario is uncertain; the eastern townships of Quebec are near the boundaries both of the two provinces of the Eastern Americas Realm, and of the Eastern Americas Realm and the Old World Realm. End_of_Article - Last_Page 1170------------

Brachiopod community paleoecology, paleobiogeography, and depositional topography of the Devonian Onondaga Limestone and correlative strata in eastern North America

The Emsian? through early Eifelian Onondaga Limestone of the Appalachian Basin was deposited in a topographic basin and on the carbonate platform which surrounded the basin on the west, north, and northeast. Onondaga strata thin from the platform into the basin. Two sedimentary cycles are present in the sub-Tioga Onondaga of eastern North America. The Edgecliff-Amherstburg represents an interval of transgression, in which epeiric seas spread over much of eastern North America. During the Nedrow-Lucas regression, the interior of the carbonate platform became restricted, resulting in the deposition of evaporites. The Moorehouse-Anderdon transgression continued through the deposition of the Tioga Bentonite, followed by the pre-Speeds-Dundee regression from the craton. Early Eifelian Appalachian Basin Onondaga brachiopod communities, arranged from nearshore to offshore, include the Atrypid-Megakozlowskiella, Atrypid-Levenea, Chonetid, Atlanticocoelia, Ambocoeliid, and Truncalosia Communities. The Onondaga-age Eastern Americas Realm is divided into the Appohimchi Province in the Appalachian Basin and the Michigan Basin-Hudson Bay Lowland Province in the Midwest. The provincial assignment of the James Bay region of Ontario is uncertain; the Eastern Townships of Quebec are near the boundaries both of the two provinces of the Eastern Americas Realm, and of the Eastern Americas Realm and the Old World Realm, the latter realm being probably in the Canadian Maritime Provinces.

Mathematical criminology : by David F. Greenberg. Rutgers University Press (30 College Avenue, New Brunswick, New Jersey 08901), 1979, 428 pp., hardcover, $19.50.

In the early twenty-first century geographers continue to examine relations between cities, towns, and what may lie beyond their perceived borders. Yet efforts are now underway to redefine the urban system canon in order to better address questions pertaining to the global system of urbanization. The approach still holds explanatory purchase for both systems of cities and cities as systems. Research agendas have been updated, however. The emphasis for interurban relations has shifted from rank to network – or from national hierarchy to transnational connectivity. Research concerning core–periphery relations at the intraurban scale increasingly takes into account the rise of massively expansive yet functionally integrated polycentric city-regions in virtually every world realm. Nonetheless, poststructuralist perspectives such as mobile urbanism pose further challenges to system-based constructs.

Biogeography of late Silurian and devonian rugose corals

Three marine benthic faunal realms can be recognized in the Early and Middle Devonian. The Eastern Americas Realm consisted of most of the eastern half of North America and South America north of the Amazon. This realm extended in a southwest direction from the Devonian equator to approximately 35°S and was an isolated epicontinental sea during much of its history. The Eastern Americas Realm was bounded on the west by the Transcontinental Arch, on the north by the Canadian Shield and on the east and southeast by a peninsular extension of the Old Red Continent. These barriers were emergent during much, but not all, of Devonian time. Seaways beyond these barriers belonged to the Old World Realm. The Malvinokaffric Realm that was farther south was apparently temperate to arctic in climate and latitudinal position and contained few corals. Rugose corals in the Eastern Americas Realm show increasing generic-level endemism from the Late Silurian through the Early Devonian; during the late Early Devonian, 92% of the rugosan genera are not known anywhere else in the world. Endemism decreased through the Middle Devonian to zero in the early Late Devonian. The Early Devonian increase in endemism paralleled, and was probably related to, the development of the Old Red Continent as a barrier between America and Africa—Europe. The waning of endemism in the Middle Devonian reflects the breaching of the land barriers. This permitted some migration in and out of the realm in early Middle Devonian time but greatest movements were in late Middle Devonian time. Principal migration directions were from western or Arctic North America into the Michigan-Hudson Bay area and from the southern Appalachian area into Africa.

Principles underlying ciliary activity in the respiratory tract. III. The independence of tracheal cilia in vivo of drug and neurogenous stimuli: Lucas, A. M., and Douglas, L. C.: Arch. Otolaryng. 21: 285, 1935

The Middle Devonian (late middle Givetian) Tully Formation in New York State is the type regional expression of the global Taghanic Biocrisis. It is marked by anomalous development of massive to rhythmically bedded, micritic limestone deposits within a vastly thicker Acadian foreland basin clastic succession. Lower-medial Tully carbonates record the incursion of tropical Old World Realm (OWR) taxa (Tully Fauna) and the outage of the long-standing, higher diversity, cooler-water, endemic Eastern Americas Realm (EAR) biota (Hamilton Fauna). Succeeding Tully strata record a return of the Hamilton Fauna followed by its demise due, both to replacement by the lower diversity, cosmopolitan Genesee Fauna and by the overspread of widespread anoxic bottom conditions coupled with the onset of drastically increased sediment input following Tully Group deposition.Massive, micritic limestones, yielding modest diversity Tully Fauna assemblages are particularly characteristic of the lower-medial Tully succession on the western New York Tully platform; these are coeval with nearly barren ribbon limestone and siltstone deposits in the adjacent New Berlin (east-central New York) and central Pennsylvania basins. These depocenters trapped terrigenous sediment and helped to create sediment-starved conditions on the platform. Anomalous Tully carbonate deposition is believed to be coincident with strong super estuarine water mass stratification in offshore Tully shelf and basin settings where a warmer, denser, more saline water mass flowed northward (shoreward) across the study area beneath a counter flow of oxygenated, river-influenced surface water. Dysoxic conditions would have developed below the pycnocline, favoring the Tully Fauna incursion, precipitation of carbonate mud, and possibly promoting the formation of ooidal chamosite.At least five thin (1–30 cm-thick) mappable beds of black, ooidal, chamosite, are observed in Taghanic shelf margin, slope, and basin deposits. These beds are typically intensely bioturbated, variably rich in associated siderite, contain corroded low-diversity fossil assemblages, and are regionally associated with condensed lag deposits above unconformities. Work by others suggests that chamosite formation occurs under minimally reducing, post-oxic, interstitial conditions which are followed, in turn, by more strongly reducing conditions which allow for variable siderite and pyrite formation. Terrestrial pedogenic alteration of silicates by evolving land plant communities under warm, humid conditions led to an increased supply of kaolinite as well as Iron oxides and hydroxides that served as precursors to chamosite formation. In the New Berlin Basin, the transgressive, top-Hamilton-base-Taghanic succession is marked by a succession of diastems associated with basin deepening and upward-increasing chamosite occurrence in dysoxic facies. Occurrence of ooidal chamosite in upper medial Tully platform deposits (Smyrna Bed) may reflect water mass stratification and extreme sediment-starvation at the shelf margin. Eastward spectral transformation of sparsely fossiliferous Smyrna ooidal chamosite in the western New Berlin Basin into richly fossiliferous, non-chamositic, equivalent neritic deposits east of that basin, suggests that the counter-flow of oxygen and nutrient-rich, lower salinity water had blocked the denser, restricted water layer from advancing over the eastern Tully clastic shelf closer to shore.