Llandovery secuicollactinae and rotasphaeridae (radiolaria) from the Cape Phillips Formation, Cornwallis Island, Arctic Canada

1998 ◽  
Vol 72 (4) ◽  
pp. 585-604 ◽  
Author(s):  
Eugene W. MacDonald
Keyword(s):  
New Species ◽  
New Genus ◽  
Arctic Canada ◽  
Cape Phillips Formation ◽  
Cornwallis Island ◽  
Lattice Shells

Radiolaria extracted from two bedded-limestone and two limestone-concretion samples from the upper Llandovery of the Cape Phillips Formation, Cornwallis Island, allow the distinction between the spicular haplentactinid subfamily Secuicollactinae and the nonspicular Rotasphaeridae. This restores Secuicollactinae and returns Secuicollacta to the subfamily from the Rotasphaeridae. Secuicollactinae represent 36 percent of the fauna and are assigned to three genera, Secuicollacta, Diparvapila new genus, and Parvalanapila new genus; these form 27, five, and three percent of the fauna, respectively. The remaining one percent of the subfamily is unassigned. Rotasphaeridae form four percent of the fauna and are represented by Rotasphaera. Secuicollacta is diagnosed on the basis of the presence of an ectopic spicule in addition to several rotasphaeridlike primary units. The salient characters of Diparvapila include two lattice shells with an ectopic spicule on the medullary shell. Parvalanapila is diagnosed on the basis of a lattice sphere overlain by a labyrinthine layer and an ectopic spicule on the lattice sphere. New species described here are Secuicollacta malevola, S. sceptri, S. gliris, S. herrimani, S. segari, S. vallipuellae, S. resodiosae, S. glaebosa, S. teli, Diparvapila hicocki, D. saintrochae, D. larseni, Parvalanapila fleischerorum, and Rotasphaera severa. Four species of Secuicollacta are reported in open nomenclature, as are two of Diparvapila and two of Rotasphaera.

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.

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.

Silurian trilobites from arctic Canada

1979 ◽  
Vol 116 (1) ◽  
pp. 1-19 ◽  
Author(s):  
A. T. Thomas ◽  
G. M. Narbonne
Keyword(s):  
New Species ◽  
Arctic Canada ◽  
Subtidal Environment ◽  
Storm Wave ◽  
Shallow Subtidal ◽  
Cornwallis Island

SummaryTrilobites of upper Ludlow age are described from Member A of the Read Bay Formation on Cornwallis Island. Four new species are represented: Helokybe spio gen. et sp.nov. (Dechenellinae), Encrinurus hyperboreus sp. nov., Kailia? capra sp.nov. (Encrinurinae) and Hemiarges echinatus sp.nov. Other taxa present are: an effaced scutelluid; Cyphaspis sp.; a warburgelline; two more encrinurids; two other forms of Hemiarges. The trilobites occur in sediments indicative of a shallow subtidal environment, with the exception of the warburgelline which occurs in sediments deposited under deeper subtidal conditions below storm wave-base.

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.

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.

The brachymetopid trilobite Radnoria in the Silurian (Wenlock) of New York State and Arctic Canada

2005 ◽  
Vol 42 (12) ◽  
pp. 2087-2096
Author(s):  
Jonathan M Adrain ◽  
Denis K Tetreault
Keyword(s):  
New York ◽  
New Species ◽  
New York State ◽  
Arctic Canada ◽  
York State ◽  
Cape Phillips Formation ◽  
Three New Species

Radnoria bretti n. sp., from the Wenlock (Sheinwoodian) Rochester Formation of western New York State, is the best preserved and most completely known member of its genus. It provides the first definitive information on Radnoria's hourglass-shaped rostral plate, the first known hypostome of a Silurian member of the genus, demonstrates that Radnoria engaged in sphaeroidal enrollment, and reveals that early holaspid individuals had tubercles on the posterior thoracic axes and pygidial axial rings that were effaced with maturity. Three new species from the Wenlock of the Cape Phillips Formation of Nunavut are known from sparse material and are reported in open nomenclature. Together, the species greatly increase knowledge of Laurentian Silurian brachymetopids, which have until now been known from a single cranidium from the Wenlock of Arkansas.

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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