Uncompressed specimens of Monograptus turriculatus (Barrande, 1850) from Cornwallis Island, Arctic Canada

1986 ◽  
Vol 23 (4) ◽  
pp. 579-582 ◽  
Author(s):  
M. J. Melchin ◽  
A. C. Lenz
Keyword(s):  
Canadian Arctic ◽  
Arctic Canada ◽  
Lateral Asymmetry ◽  
Cape Phillips Formation ◽  
Lateral Curvature ◽  
Cornwallis Island

Isolated specimens of Monograptus turriculatus (Barrande, 1850) have been recovered from calcite concretions of the turriculatus Zone (late Llandovery) from the Cape Phillips Formation, Canadian Arctic Islands. The sicula shows ventral as well as dextral lateral curvature, and the thecae show a pronounced lateral asymmetry. This asymmetry is manifest as a tear-shaped aperture, a long, laterally directed spine on the outer apertural margin, and a shorter, ventrally directed spine on the inner apertural margin. The latter spine is totally absent on the proximal thecae.Monograptus sedgwickii (Portlock, 1853) is suggested as a possible ancestor to M. turriculatus.

A new Silurian Astylospongid sponge from Baillie-Hamilton Island, Canadian Arctic Archipelago

1978 ◽  
Vol 15 (1) ◽  
pp. 157-162 ◽  
Author(s):  
J. Keith Rigby ◽  
Alfred C. Lenz
Keyword(s):  
Canadian Arctic ◽  
Canadian Arctic Archipelago ◽  
Arctic Canada ◽  
Uniform Size ◽  
Cape Phillips Formation

The new sponge, Astylospongiella megale, is described from rocks of the Ludlovian Neodiversograptus nilssoni Zone of the Cape Phillips Formation from southern Baillie-Hamilton Island, Arctic Canada. The genus is included in Astylospongiidae because its skeletal net is composed of sphaeroclones, which in this species, are of relatively uniform size throughout the sponge. The new sponge also has irregularly placed radiating canals which are subparallel to the upper surface, and which are cross-connected by upward fanning canals that are approximately normal to the sponge surface and the radiating canals.

A new Gorstian radiolarian fauna from the upper Silurian of the Cape Phillips Formation, Cornwallis and Bathurst islands, Canadian Arctic

2015 ◽  
Vol 52 (10) ◽  
pp. 863-879 ◽  
Author(s):  
Martin Tetard ◽  
Paula J. Noble ◽  
Taniel Danelian ◽  
Claude Monnet ◽  
Alfred C. Lenz
Keyword(s):  
Canadian Arctic ◽  
Alpha Diversity ◽  
Siliceous Sponge ◽  
Sponge Spicule ◽  
Cape Phillips Formation ◽  
Cortical Shell ◽  
Stratigraphic Ranges ◽  
Shelf Margin ◽  
Cornwallis Island

This study provides a taxonomic treatment and comparison of lower Gorstian (Silurian) radiolarians recovered from two sections of the Cape Phillips Formation in the Canadian Arctic that accumulated in two different paleoenvironmental settings. Twilight Creek is more basinal, located ∼100 km from the paleo-shelf margin, whereas Snowblind Creek is located within 1 km of the paleo-shelf break, on Cornwallis Island. The fauna, like other material from the Cape Phillips Formation, is extremely well preserved and was recovered from four samples at two localities, all from the Lobograptus progenitor graptolite Zone, an interval that has few published studies regarding radiolarians. A total of 28 species are recognized, of which two are new and described herein (Fusalfanus bilateralis n. sp. and Pseudospongoprunum parvispina n. sp.), belonging to the Haplotaeniatidae, Inaniguttidae, “Sponguridae”, Ceratoikiscidae, Entactiniidae, Palaeoscenidiidae, and Secuicollactidae. Based on these new data, the stratigraphic ranges of some taxa are extended. The species concepts of several closely related inaniguttid species are re-evaluated. As a result, Inanihella tarangulica Nazarov and Ormiston, 1984 is transferred to the genus Fusalfanus Furutani, 1990 based on cortical shell structure, and Inanihella duroacus, Inanihella legiuncula, and Inanihella perarmata are synonymized under Fusalfanus tarangulica sensu lato. Aciferopylorum admirandum is transferred to Fusalfanus and considered a junior synonym of Fusalfanus osobudaniensis. The comparative analysis of taxonomic richness and composition reveals that the more distal sample from Bathurst Island exhibits a slight, but statistically significant, higher alpha diversity at the species rank than the more proximal basin/platform samples from Snowblind Creek. Biodiversity indices at the genus rank produced mixed results, indicating that differences between sites are at best slight. There is also a strong taxonomic separation between the fine and coarse size radiolarian fractions recovered during the sieving of each sample. The siliceous sponge spicule assemblages from these faunas show an inverse diversity relationship to the radiolarians in that Snowblind Creek contains greater alpha diversity than Twilight Creek. This study provides the first documentation of facies-controls in Silurian radiolarian diversity and is useful in evaluating the role of taxa used in biostratigraphy.

Systematics of the Acanthoparyphinae (Trilobita), by species from the Silurian of Arctic Canada

1998 ◽  
Vol 72 (4) ◽  
pp. 698-718 ◽  
Author(s):  
Jonathan M. Adrain
Keyword(s):  
New Species ◽  
Type Species ◽  
Cladistic Analysis ◽  
Canadian Arctic ◽  
Entire Group ◽  
Arctic Canada ◽  
Basal Node ◽  
The Family ◽  
Cape Phillips Formation ◽  
Basal Structure

Cladistic analysis of the trilobite subfamily Acanthoparyphinae Whittington and Evitt, 1954, yields an explicit hypothesis of relationship for the group. All Silurian species together form a robustly supported monophylum including the genera Hyrokybe Lane, 1972, Parayoungia Chatterton and Perry, 1984, and Youngia Lindström, 1885. Sister to this is the Ordovician type species of Acanthoparypha Whittington and Evitt, 1954. Remaining species that have historically been assigned to either Acanthoparypha or Pandaspinapyga Esker and Levin, 1964, form a rather labile paraphylum. Nevertheless, the entire group thus identified is definitely monophyletic, and supported by several prominent synapomorphic character-states.The basal structure and basal node of the subfamily are more difficult to assess. The relationships of the genera Hammannopyge Přibyl, Vaněk, and Pek, 1985, Holia Bradley, 1930, and Nieszkowskia Schmidt, 1881, need to be addressed within the wider context of the family as a whole. The traditional assignment of Holia to the acanthoparyphines is followed.Wenlock acanthoparyphines from the Cape Phillips Formation of the central Canadian Arctic islands include several species of Hyrokybe and Parayoungia. They are similar to, and in one case conspecific with, coeval forms to the southwest in the southern Mackenzie Mountains.Five species are new: Holia glabra, Hyrokybe lightfooti, Hyrokybe youngi, Hyrokybe mitchellae, and Parayoungia mclaughlini. At least four other potentially new species are reported in open nomenclature.

Complex noncalcified macroalgae from the Silurian of Cornwallis Island, Arctic Canada

2011 ◽  
Vol 85 (1) ◽  
pp. 111-121 ◽  
Author(s):  
Steven T. Loduca ◽  
Michael J. Melchin ◽  
Heroen Verbruggen
Keyword(s):  
New Taxa ◽  
Florida Bay ◽  
Central Axis ◽  
Arctic Canada ◽  
Green Algal ◽  
Cape Phillips Formation ◽  
Macroalgal Assemblage ◽  
Algal Material ◽  
Fifth Order ◽  
Cornwallis Island

Thin beds of silty limestone within a Ludlovian (Ludfordian) section of the Cape Phillips Formation on Cornwallis Island, Arctic Canada, contain numerous specimens of noncalcified macroalgae in association with dendroid and graptoloid graptolites, brachiopods, and trilobites. The algal material, preserved as carbonaceous compressions, represents three new taxa, each characterized by a central axis surrounded by laterals. Laterals ofEocladus xiaoin. gen. n. sp. are thin and branch to the fifth order whereas those ofChaetocladus captitatusn. sp. are undivided and form a distinctive capitulum. Thalli ofPalaeocymopolia nunavutensisn. gen. n. sp. have a branched, serial-segmented form and a corticated structure. On the basis of thallus architecture, all three taxa are assigned to the extant green algal order Dasycladales. Parallels exist between this macroalgal assemblage and a modern macroalgal association in Florida Bay.

The Ordovician–Silurian boundary on Cornwallis and Truro islands, Arctic Canada: preliminary data

1991 ◽  
Vol 28 (11) ◽  
pp. 1854-1862 ◽  
Author(s):  
Michael J. Melchin ◽  
Alexander D. McCracken ◽  
Fred J. Oliff
Keyword(s):  
Sea Level ◽  
Arctic Canada ◽  
Faunal Turnover ◽  
Sea Level Fluctuations ◽  
Continuous Sequence ◽  
Cape Phillips Formation ◽  
Show Evidence ◽  
Conodont Zone ◽  
Continuous Sedimentation ◽  
Cornwallis Island

Four sections of the lower part of the Cape Phillips Formation, two outcrops on northeastern Cornwallis Island and one outcrop and one drill core from Truro Island, Northwest Territories, Canada, provide significant new data on the Ordovician–Silurian boundary. They show evidence of continuous sedimentation through the boundary interval and a continuous sequence of graptolite zones, including the bohemicus and persculptus zones, which have not been previously found in Arctic Canada. Strata yield graptolites, including uncompressed specimens, and conodonts through most of the sections. The ordovicicus conodont Zone occurs within the pacificus to lower persculptus graptolite zones. The nathani conodont Zone contains a "transitional fauna," a mixing of species typical of the preceeding ordovicicus Zone and those generally regarded as Silurian indicators. This conodont zone ranges from the middle of the persculptus graptolite Zone into the lower acuminatus graptolite Zone and, thus, spans the Ordovician–Silurian boundary. The Ordovician–Silurian faunal turnover of the conodonts, therefore, also spans the Ordovician–Silurian boundary and is not coincident with the interval of major graptolite extinction, which occurs earlier, at the end of the pacificus Zone. The base of the kentuckyensis conodont Zone occurs in the acuminatus graptolite Zone. Sedimentologic evidence of the maximum eustatic sea-level drop can be seen within the bohemicus Zone (early Hirnantian) and possibly one or several smaller scale sea-level fluctuations through the underlying zones.

Phacopid trilobites from the Silurian of Arctic Canada

1996 ◽  
Vol 70 (6) ◽  
pp. 1091-1094 ◽  
Author(s):  
Jonathan M. Adrain ◽  
Eugene W. MacDonald
Keyword(s):  
Canadian Arctic ◽  
Minor Component ◽  
Arctic Canada ◽  
The Family ◽  
Cape Phillips Formation ◽  
The Subject

Diverse silicified trilobite faunas from the lower Wenlock to lower Ludlow of the Cape Phillips Formation, central Canadian Arctic, have been the subject of works by Perry and Chatterton (1977), Chatterton and Perry (1979), Adrain (1994), and Adrain and Edgecombe (1995, and in press). The present work describes a very minor component of these faunas, the family Phacopidae, which is nevertheless of considerable biogeographic interest.

A Bohemian-type Silurian (Wenlockian) pelecypod faunule from Arctic Canada

1987 ◽  
Vol 61 (3) ◽  
pp. 508-520 ◽  
Author(s):  
John Pojeta ◽  
B. S. Norford
Keyword(s):  
Arctic Canada ◽  
Cape Phillips Formation ◽  
First Time ◽  
Cornwallis Island

The pelecypod genera Slava and Rhombopteria are reported for the first time from Canada, where they occur in a limestone concretion within the Cape Phillips Formation, Cornwallis Island, Arctic Archipelago. These genera are characteristic of Silurian rocks in Bohemia, Czechoslovakia. Graptolites from the same concretion indicate the Monograptus ludensis Zone (uppermost Wenlockian); this age is substantiated by associated conodonts, trilobites, vertebrates, and pelecypods but with less precision. It is difficult to explain the occurrence of Slava and Rhombopteria in the middle of Laurentia on the basis of some map reconstructions of the Wenlockian world.The Canadian material of Slava novaterra n. sp. and Rhombopteria cf. R. mira (Barrande) is described. Leptodesma (Leptodesma) sp. A and an indeterminate grammysiid pelecypod from the same concretion are illustrated. Information is provided to show that Newsomella Foerste, from Wenlockian–Ludlovian rocks of Illinois, Wisconsin, and Tennessee, is not a subgenus of Rhombopteria Jackson.

scholarly journals Hirnantian (Ordovician) through Wenlock (Silurian) conodont biostratigraphy, bioevents, and integration with graptolite biozones, Cape Phillips Formation slope facies, Cornwallis Island, Canadian Arctic Islands

2017 ◽  
Vol 54 (9) ◽  
pp. 936-960 ◽  
Author(s):  
Shunxin Zhang ◽  
David M.S. Jowett ◽  
Christopher R. Barnes
Keyword(s):  
Carbonate Platform ◽  
Canadian Arctic ◽  
New Genus And Species ◽  
Dynamic Nature ◽  
Ocean Climate ◽  
Extinction Event ◽  
Cape Phillips Formation ◽  
Geochemical Studies ◽  
Relationship Of ◽  
Cornwallis Island

Cornwallis Island in the Canadian Arctic Archipelago provides one of the world’s best areas for establishing an integrated graptolite–conodont biozonation for the Late Ordovician – Silurian given the well-exposed interfingering relationship of the basinal shale and carbonate platform facies. Building on earlier graptolite work, 180 samples were collected from nine sections of the Cape Phillips Formation, of which 118 yielded approximately 7600 conodont elements representing 54 species in 25 genera, including one new genus and species, Mayrodus melchini; the conodonts are well preserved, with minimal thermal alteration (colour alteration index, CAI 1). Nine conodont zones are recognized and defined for this region, namely the Amorphognathus ordovicicus, Distomodus kentuckyensis, Aspelundia expansa, As. fluegeli, and Pterospathodus celloni Interval zones, Pt. a. amorphognathoides Taxon-range Zone, Pt. pennatus procerus and Kockelella ranuliformis Highest-occurrence zones, and K. ortus absidata Taxon-range Zone. An integration of graptolite and conodont zones is documented. Earlier paleontological and isotope geochemical studies have demonstrated the dynamic nature of the Silurian ocean–climate system and identified major faunal turnovers or events. Five of these are recognized in the Cornwallis fauna and related to oceanographic and climate changes, in part referring to recent oxygen isotope data from conodonts from the Cornwallis collections: Hirnantian extinction event, Sandvika Event (late Aeronian, Llandovery), Snipklint Primo Episode (early Telychian, Llandovery), Ireviken Event (late Telychian, Llandovery–Sheinwoodian, Wenlock), and Mulde Event (early Homerian, Wenlock).

The lichid trilobite Borealarges n. gen., with species from the Silurian of Arctic Canada

1994 ◽  
Vol 68 (5) ◽  
pp. 1081-1099 ◽  
Author(s):  
Jonathan M. Adrain
Keyword(s):  
New Species ◽  
Phylogenetic Relationships ◽  
Debris Flows ◽  
Type Species ◽  
Canadian Arctic ◽  
Arctic Canada ◽  
Cape Phillips Formation

Borealarges n. gen. (type species B. reedi n. gen. and sp.) is a group of trochurine trilobites of mainly northern Laurentian distribution, closely related to both Richterarges Phleger and Terranovia Maximova. Richterarges is restricted to a Laurentian Ludlow-Přídolí clade of unambiguous monophyly. Taken together, the genera form a monophyletic subdivision of Trochurinae. Phylogenetic relationships within this clade are poorly resolved. The precise relationships of some members of the group are difficult to determine at present, and these species are referred to Borealarges sensu lato. Members of Borealarges are ubiquitous elements of silicified Wenlock–Ludlow trilobite faunas contained in debris flows of the Cape Phillips Formation of the central Canadian Arctic. At present, known post-Wenlock diversity of Borealarges is exclusively northern Laurentian, although this may be a function of lack of study in other areas. New species include B. reedi, B. morrisoni, and B. tuckerae, and B. s.l. B. calei. Borealarges mikulicorum (Perry and Chatterton) is revised.

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