Early Devonian age of the Detroit River Group, inferred from Arctic stromatoporoids

1993 ◽  
Vol 30 (12) ◽  
pp. 2465-2474 ◽  
Author(s):  
Eric C. Prosh ◽  
Colin W. Stearn
Keyword(s):  
United States ◽  
Close Relationships ◽  
Species Level ◽  
Ellesmere Island ◽  
The Arctic ◽  
Early Devonian ◽  
Detroit River ◽  
Devonian Age ◽  
First Time ◽  
Group Species

The Detroit River Group of southwestern Ontario and the adjacent United States has traditionally been considered mostly or entirely Middle Devonian in age. Detroit River Group faunas are, however, highly endemic and difficult to correlate to the chronostratigraphic standard; widely accepted conodont-based ages are similarly constrained by endemism and rely heavily upon inferential correlations. Recent evidence from the Blue Fiord Formation of southwestern Ellesmere Island suggests an Emsian (late Early Devonian) age for the full Detroit River Group, based upon shared stromatoporoid species. Four Detroit River Group species, Stromatoporella perannulata Galloway and St. Jean, Stictostroma mamilliferum Galloway and St. Jean, Habrostroma proxilaminata (Fagerstrom), and Parallelopora campbelli Galloway and St. Jean, are recognized for the first time in the Arctic. In addition, Blue Fiord Formation (and younger) species of Trupetostroma and Pseudoactinodictyon demonstrate close relationships to Detroit River Group species. Together, the stromatoporoid evidence and the available conodont data imply a serotinus age for the Amherstburg Formation and a serotinus to patulus age for the Lucas Formation. This is the first direct species-level correlation of a Detroit River Group "endemic" to a globally dateable level and the first regional application of stromatoporoid biostratigraphy in North America.

A new fossil occurrence from the Vendom Fiord Formation (type area), Ellesmere Island

1978 ◽  
Vol 15 (10) ◽  
pp. 1675-1679 ◽  
Author(s):  
D. G. Perry
Keyword(s):  
Sea Level ◽  
North American ◽  
Ellesmere Island ◽  
The Arctic ◽  
Early Devonian ◽  
The North ◽  
Type Area ◽  
Formation Type ◽  
Devonian Age

Probable reworked Lochkovian (early Early Devonian) brachiopods and conodonts were recovered from the basal clastic beds of the Vendom Fiord Formation in the type area on central Ellesmere Island. Although most of the fossils are reworked from underlying strata, none appear to be younger than Lochkovian. Data obtained by other workers from more northerly exposures of the Vendom Fiord Formation show that the lower part of the formation is no older than late Pragian (middle Early Devonian). Elsewhere, the North American Early Devonian eustatic sea-level minimum occurs in the Pragian and is followed by transgressive deposits of late Early Devonian age of which the Vendom Fiord Formation possibly represents the basal transgressive unit in the Arctic Archipelago.

Molecular identification of cyst-forming nematodes (Heteroderidae) from Iran and a phylogeny based on ITS-rDNA sequences

Nematology ◽  
2003 ◽  
Vol 5 (1) ◽  
pp. 99-111 ◽  
Author(s):  
Zahra Tanha Maafi ◽  
Sergei Subbotin ◽  
Maurice Moens
Keyword(s):  
Phylogenetic Analyses ◽  
Species Level ◽  
Its Rdna ◽  
Heterodera Avenae ◽  
Published Data ◽  
Rdna Sequences ◽  
First Time ◽  
Group Species ◽  
High Support ◽  
Different Parts

Abstract RFLP and sequences of ITS-rDNA of 45 populations of cyst-forming nematodes collected from different parts of Iran were analysed and identified as representatives of 21 species. Eight enzymes generated RFLP for all studied populations. Comparison of RFLP profiles and sequences of the ITS regions with published data confirmed the presence of Heterodera avenae, H. filipjevi, H. glycines, H. hordecalis, H. latipons, H. schachtii and H. trifolii in Iran. RFLP patterns and ITS sequences for H. elachista, H. turcomanica, H. mothi and C. cacti were obtained for the first time in this study. Heterodera humuli, H. goettingiana, H. fici, H. elachista, H. turcomanica and Cactodera cacti are recorded for the first time in Iran. These results correspond with morphological and morphometric identification of the populations. Several populations were not identified at the species level and are attributed to Heterodera sp.; some of these may correspond to new species. Twenty-one new sequences from Iranian cyst-forming nematodes and 36 known sequences were used for the phylogenetic analyses. The cyst-forming nematodes formed several clades corresponding to their morphological features. Heterodera mothi and H. elachista clustered with high support with other Cyperi group species and H. turcomanica formed a moderately to highly supported clade with the Humuli group.

Salamander tracks (Ambystomichnus?) from the Cathedral Bluffs tongue of the Wasatch Formation (Eocene), northeastern Green River Basin, Wyoming

2001 ◽  
Vol 75 (4) ◽  
pp. 901-904 ◽  
Author(s):  
John R. Foster
Keyword(s):  
United States ◽  
Skeletal Remains ◽  
Ellesmere Island ◽  
Green River Formation ◽  
Western United States ◽  
The Arctic ◽  
Early Eocene ◽  
Green River Basin ◽  
Green River ◽  
Vertebrate Tracks

Vertebrate tracks are comparatively rare in Tertiary deposits of the western United States. Unlike the deposits of the Mesozoic in this region, in which each formation often has several dozen known tracksites, there are only a few known sites in Paleocene units of the region (Lockley and Hunt, 1995), and though the Eocene Green River Formation contains relatively numerous tracks, especially those of birds, there are only a few taxa represented. The occurrence of amphibian tracks in the Eocene Wasatch Formation is therefore of interest, not only in that it adds to the known ichnological record of the Tertiary of the western United States but also in that the tracks indicate the presence of an otherwise under-represented member of the vertebrate paleofauna of the time. Skeletal remains of amphibians are present but not common in many Tertiary formations of the western United States, and remains of large salamanders are rare. Only the large caudate Piceoerpeton is known from the Tiffanian and Clarkforkian of Montana and Wyoming (Naylor and Krause, 1981), and its only Wasatchian occurrence is at Ellesmere Island, north of the Arctic Circle. The tracks described here appear to represent a nearly Piceoerpeton-sized salamander in the lacustrine shoreline deposits of the early Eocene Wasatch Formation of southwestern Wyoming.

Primitive cladid crinoids from the early Osagean Burlington Limestone and the phylogenetics of Mississippian species of Cyathocrinites

2003 ◽  
Vol 77 (1) ◽  
pp. 121-138 ◽  
Author(s):  
Thomas W. Kammer ◽  
Forest J. Gahn
Keyword(s):  
United States ◽  
Phylogenetic Analysis ◽  
Species Level ◽  
East Central ◽  
The North ◽  
Middle Mississippian ◽  
Evolutionary Radiation ◽  
Central United States ◽  
Morphologic Data ◽  
First Time

All 19 known species of the primitive cladid crinoid genera Atelestocrinus, Cyathocrinites, Goniocrinus, Parisocrinus, Pellecrinus, and Zygotocrinus from the early Osagean Burlington Limestone of the North American midcontinent are reviewed and redescribed or, where necessary, redefined. Nine of these species are illustrated for the first time herein. Sixteen are considered valid, including C. deroseari n. sp. Of the remaining three species, one is left in open nomenclature, and two are considered nomen dubia. Pellecrinus is recognized for the first time from the Burlington Limestone, although the specimens can not be identified to the species level and are left in open nomenclature.Cyathocrinites ranges from the Middle Silurian to at least the Middle Mississippian. During the Early Mississippian Cyathocrinites experienced an evolutionary radiation with a maximum diversity of nine species in the Burlington Limestone. Phylogenetic relationships were investigated in a parsimony-based phylogenetic analysis by combining morphologic data from the Burlington species with data from the four other species of Cyathocrinites from the late Osagean and early Meramecian of the east-central United States. The Kinderhookian C. chouteauensis (Miller and Gurley, 1896) served as the outgroup. A phylogenetic analysis of 14 species of Mississippian Cyathocrinites yielded a single most parsimonious tree with a length of 28 steps (C. I. = 0.607, H. I. = 0.392, R. I. = 0.718, R. C. = 0.436). Results of this analysis suggest that at least two major clades existed within Mississippian Cyathocrinites. One clade contains C. sampsoni (Miller, 1891b), C. gilesi (Wachsmuth and Springer, 1878), C. farleyi (Meek and Worthen, 1866), and C. barydactylus (Wachsmuth and Springer, 1878). The second clade contains C. iowensis, C. kelloggi (White, 1862), C. barrisi (Hall, 1861a), C. rigidus, C. deroseari n. sp., C. asperrimus (Springer, 1911), C. lamellosus (White, 1863), and C. harrodi (Wachsmuth and Springer, 1880). Cyathocrinites multibrachiatus forms a polytomy with these two clades. Members of the first clade exhibit a unique overall morphology present only during the Mississippian, suggesting the clade arose during this time. Members of the second clade, plus C. multibrachiatus, exhibit some characters present in Cyathocrinites species as old as the Middle Silurian and, thus, may have its roots among Silurian and Devonian species.

scholarly journals A new Early Devonian (Emsian) arthrodire from the Northwest Territories, Canada, and its significance for paleogeographic reconstruction

2017 ◽  
Vol 54 (5) ◽  
pp. 461-476 ◽  
Author(s):  
Hans-Peter Schultze ◽  
Stephen L. Cumbaa
Keyword(s):  
Northwest Territories ◽  
Arctic Region ◽  
Shoulder Girdle ◽  
The Arctic ◽  
Svalbard Archipelago ◽  
Early Devonian ◽  
Red Sandstone ◽  
Marine Deposits ◽  
The Baltic ◽  
First Time

An heterostiid arthrodire, Herasmius dayi sp. nov., is described from upper Lower Devonian marine deposits of the Bear Rock Formation along the Anderson River, Northwest Territories, Canada. New elements described for the genus for the first time include the suborbital, submarginal (also new for the family Heterostiidae), the lateral shoulder girdle with posterior lateral, anterior dorso-lateral, and posterior dorso-lateral plates and possible infragnathal plate. We present a new reconstruction of the cranial region of Herasmius, previously known only from supposedly freshwater – shallow marine deposits of roughly the same age in the Wood Bay Group of Spitsbergen. The late Early Devonian fishes that are common to the Arctic region of northwestern Canada and the island of Spitsbergen in the Svalbard archipelago of Norway, the porolepiform Heimenia and the arthrodire Herasmius described here, demonstrate the existence of a barrier-free paleogeographic connection between those continental blocks by the late Early Devonian. Comparison of the entire Anderson River vertebrate fauna with other boreal faunas of similar age indicates additional paleogeographic connections north of and around the Old Red Sandstone Continent to the Baltic region, central Europe, and even to the New Siberian Islands and South China, in contrast to most current published paleogeographical reconstructions.

Middle Devonian brachiopods from the Bird Fiord Formation, Arctic Canada

2003 ◽  
Vol 77 (2) ◽  
pp. 243-266 ◽  
Author(s):  
Li Rong-Yu ◽  
Brian Jones
Keyword(s):  
New Species ◽  
Middle Devonian ◽  
Canadian Arctic ◽  
Ellesmere Island ◽  
The Arctic ◽  
Arctic Canada ◽  
Early Devonian ◽  
Delta Plain ◽  
The Cross

The late Early Devonian to Middle Devonian Bird Fiord Formation, which is up to 900 m thick, is exposed along an extensive outcrop belt from stretches from Ellesmere Island to Bathurst Island in Arctic Canada. This formation, which encompasses sediments that accumulated in sabkha, deltaic, and shelf settings, is divided into six members. The Blubber Point, Baad Fiord, Norwegian Bay, and Cardigan Strait members, which include sediments that formed on an open marine shelf, are characterized by a diverse biota of brachiopods, mollusks, corals, trilobites, and sponges. The Cross Bay and Grise Fiord members, which encompass sediments that formed in a sabkha and delta plain settings, respectively, are generally devoid of fossils.A collection of 47,026 brachiopods, which came from 140 collections made at 34 locations throughout the outcrop belt of the Bird Fiord Formation, contains 22 species of brachiopods that belong to 21 genera. This biota includes six new species: Gypidula mega, Spinatrypa (Isospinatrypa) parva, Desquamatia (Independatrypa) fortis, Nucleospira stelcki, Warrenella grinnellensis, and Cranaena briceae. Four genera (Arcticastrophia Li and Jones, 2002, Borealistrophia Li and Jones, 2002, Grinnellathyris Li and Jones, 2002, and Costacranaena Johnson and Perry, 1976) and 16 species of brachiopods are endemic to the Arctic Canada. Conversely, the fauna also includes European elements such as Nucleospira lens (Schnur), Spinatrypa (Isospinatrypa), and Warrenella. These taxa may indicate that there was some communication between the Canadian Arctic and Europe during Middle Devonian.

scholarly journals Sequences, stratigraphy and scenarios: what can we say about the fossil record of the earliest tetrapods?

2010 ◽  
Vol 278 (1704) ◽  
pp. 432-439 ◽  
Author(s):  
Matt Friedman ◽  
Martin D. Brazeau
Keyword(s):  
Fossil Record ◽  
Large Scale ◽  
Past Research ◽  
Species Level ◽  
Late Devonian ◽  
Early Devonian ◽  
Order Of Magnitude ◽  
Evolutionary Event ◽  
Devonian Age ◽  
Late Emsian

Past research on the emergence of digit-bearing tetrapods has led to the widely accepted premise that this important evolutionary event occurred during the Late Devonian. The discovery of convincing digit-bearing tetrapod trackways of early Middle Devonian age in Poland has upset this orthodoxy, indicating that current scenarios which link the timing of the origin of digited tetrapods to specific events in Earth history are likely to be in error. Inspired by this find, we examine the fossil record of early digit-bearing tetrapods and their closest fish-like relatives from a statistical standpoint. We find that the Polish trackways force a substantial reconsideration of the nature of the early tetrapod record when only body fossils are considered. However, the effect is less drastic (and often not statistically significant) when other reliably dated trackways that were previously considered anachronistic are taken into account. Using two approaches, we find that 95 per cent credible and confidence intervals for the origin of digit-bearing tetrapods extend into the Early Devonian and beyond, spanning late Emsian to mid Ludlow. For biologically realistic diversity models, estimated genus-level preservation rates for Devonian digited tetrapods and their relatives range from 0.025 to 0.073 per lineage-million years, an order of magnitude lower than species-level rates for groups typically considered to have dense records. Available fossils of early digited tetrapods and their immediate relatives are adequate for documenting large-scale patterns of character acquisition associated with the origin of terrestriality, but low preservation rates coupled with clear geographical and stratigraphic sampling biases caution against building scenarios for the origin of digits and terrestrialization tied to the provenance of particular specimens or faunas.

A Well-Ordered Thing

2018 ◽  
Author(s):  
Michael D. Gordin
Keyword(s):  
Nineteenth Century ◽  
History Of Science ◽  
Periodic Table ◽  
The Arctic ◽  
Classic Work ◽  
Hot Air ◽  
History Of ◽  
First Time

Dmitrii Mendeleev (1834–1907) is a name we recognize, but perhaps only as the creator of the periodic table of elements. Generally, little else has been known about him. This book is an authoritative biography of Mendeleev that draws a multifaceted portrait of his life for the first time. As the book reveals, Mendeleev was not only a luminary in the history of science, he was also an astonishingly wide-ranging political and cultural figure. From his attack on Spiritualism to his failed voyage to the Arctic and his near-mythical hot-air balloon trip, this is the story of an extraordinary maverick. The ideals that shaped his work outside science also led Mendeleev to order the elements and, eventually, to engineer one of the most fascinating scientific developments of the nineteenth century. This book is a classic work that tells the story of one of the world's most important minds.

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