Insolitignum n.gen. and Palaeoephippium Goodbody 1986 (Radiolaria) from the Lower Silurian of the Cape Phillips Formation, Arctic Canada

1999 ◽  
Vol 36 (12) ◽  
pp. 2051-2057 ◽  
Author(s):  
Eugene W. MacDonald
Keyword(s):  
Arctic Canada ◽  
Lower Silurian ◽  
Cape Phillips Formation

Insolitignum n.gen. and Palaeoephippium Goodbody 1986 (Radiolaria) from the Lower Silurian of the Cape Phillips Formation, Arctic Canada

1999 ◽  
Vol 36 (12) ◽  
pp. 2051-2057 ◽  
Author(s):  
Eugene W MacDonald
Keyword(s):  
New Species ◽  
Type Species ◽  
New Genus ◽  
Intermediate Position ◽  
Arctic Canada ◽  
Lower Silurian ◽  
The Family ◽  
Cape Phillips Formation ◽  
Cornwallis Island

Radiolaria of the family Palaeoscenidiidae were recovered from two bedded-limestone and two limestone-concretion samples from the upper Llandovery of the Cape Phillips Formation, Cornwallis Island, Arctic Canada. The new genus Insolitignum is defined by two apical rays, three basal rays, and a principal ray in an intermediate position. The principal ray distinguishes this genus from Palaeoephippium. Insolitignum dissimile, the type species of the new genus, was previously placed in Palaeoephippium. New species described here are Insolitignum peranima, Insolitignum vivanima, and Palaeoephippium adraini.

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.

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.

Validity and composition of the Silurian trilobite genera Borealarges and Dicranogmus, with new species from the Canadian Arctic

2003 ◽  
Vol 40 (5) ◽  
pp. 749-763 ◽  
Author(s):  
Jonathan M Adrain
Keyword(s):  
New Species ◽  
Cladistic Analysis ◽  
Species Group ◽  
Reasonable Doubt ◽  
The Arctic ◽  
Arctic Canada ◽  
New Information ◽  
Cape Phillips Formation ◽  
New Material ◽  
Three New Species

New silicified material from Arctic Canada demonstrates that the lichid trilobite genera Borealarges and Dicranogmus, recently claimed to be synonyms, are independent groups with no close phylogenetic connection to one another. Dicranogmus has been known mainly from cranidia alone; prior association of librigenae and pygidia with the Arctic Canadian species D. skinneri has been queried. This association is correct beyond reasonable doubt, based on description of new material of both D. skinneri and a new species. Three new species of Borealarges are related to B. tuckerae Adrain 1994. Cladistic analysis supports the monophyly of this species group. Pending further new information, however, the group is retained within the genus Borealarges. The stratigraphic range of the species group is extended from the lower Wenlock (Sheinwoodian) to upper Ludlow (Ludfordian) by the discovery of a rare species in the Douro Formation of Cornwallis Island, Arctic Canada. New taxa from the Wenlock of the Cape Phillips Formation, Arctic Canada, include Dicranogmus wynni, Borealarges nicoae, B. warholi, and B. yulei.

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.

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