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.

scholarly journals Silurian ostracoderms from Washington Land (North Greenland), with comments on cyathaspid structure, systematics and phyletic position

1986 ◽  
Vol 132 ◽  
pp. 89-123
Author(s):  
S.E Bendix-Almgreen
Keyword(s):  
Canadian Arctic ◽  
Stability Control ◽  
Canadian Arctic Archipelago ◽  
Marine Deposits ◽  
Type Section ◽  
Cape Phillips Formation ◽  
North Greenland

The few detached dermal elements recorded here document a new ostracoderm fauna comprising undeterminable species of one anaspid, two cyathaspids and a heterostracan which might have its closest relatives among the pteraspids. This fauna is derived from marine deposits of ultimate Wenlock or possibly Early Ludlow age at the top of the Lafayette Bugt Formation in its type section, in Washington Land, western North Greenland. It is probably equivalent to one of the undescribed faunas known from the Monograptus testis - M. nilssoni sequence of the Cape Phillips Formation in the Canadian Arctic Archipelago. Comparative material from Norway and Spitsbergen is considered in this study which prompted general comments on cyathaspid squamation, vestigial fin structure, cyathaspid systematics, their phyletic position relative to the pteraspids, system of stability control in swimming, their habitats and diets.

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.

Morphology and classification of some Early Silurian monograptids (Graptoloidea) from the Cape Phillips Formation, Canadian Arctic Islands

1997 ◽  
Vol 34 (8) ◽  
pp. 1128-1149 ◽  
Author(s):  
Jeff J. Lukasik ◽  
Michael J. Melchin
Keyword(s):  
Canadian Arctic ◽  
Canadian Arctic Archipelago ◽  
Dorsal Wall ◽  
Wall Structures ◽  
Morphological Criteria ◽  
Cape Phillips Formation ◽  
Upward Growth ◽  
Definition Of ◽  
Simultaneous Evolution

Exquisitely preserved early to mid-Llandovery monograptids have been chemically isolated from calcareous concretions sampled from the Cape Phillips Formation, central Canadian Arctic Archipelago. They provide morphological information critical in refining the definition of four of the earliest known monograptid genera, and in the elucidation of their phylogenetic dispersal through the Llandovery monograptid radiation. These primitive monograptid genera are defined primarily on the basis of derived thecal form. The specific, derived thecal and thecal apertural character states used in generic diagnoses are as follows: species of Atavograptus possess simple, geniculate to slightly sigmoidal thecae with a large dorsoventral overlap; species of Pribylograptus possess thecae bearing lateral apertural lappets that may occur with Atavograptus-style thecae proximally; species of Coronograptus possess flared thecal apertures at least part way along the rhabdosome; species of Lagarograptus have conspicuous, tongue-like, ventral apertural processes developed as ventral apertural margin outgrowths. Species of all of these genera may possess hoods that are genicular in origin, with the exception of those of Lagarograptus inexpeditus, which are dorsal wall structures. These earliest monograptid genera possess a pattern Mr astogeny, characterized by the outward, then upward growth of theca 1 from a sicular resorption porus (pattern Mr, different from younger monograptids that possess a primary porus developed during sicular astogeny (pattern Mp)). Through analysis of their defining morphological criteria in conjunction with sicular dimensions and thecal uniformity, each of these early monograptid genera is considered to be monophyletic, arising from the primitive Atavograptus stock. Atavograptus thecal morphology provided a simple template for the derivation of thecal form leading to the nearly simultaneous evolution of Pribylograptus, Coronograptus, and Lagarograptus in the lower Rhuddanian. Fourteen species belonging to four genera are described, including six new species.

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.

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.

Silurian (Wenlockian) trilobites from Baillie-Hamilton Island, Canadian Arctic Archipelago

1977 ◽  
Vol 14 (2) ◽  
pp. 285-317 ◽  
Author(s):  
D. G. Perry ◽  
B. D. E. Chatterton
Keyword(s):  
New Species ◽  
Northwest Territories ◽  
New Taxa ◽  
Canadian Arctic ◽  
Canadian Arctic Archipelago ◽  
Cape Phillips Formation ◽  
Mackenzie Mountains

Wenlockian trilobites representing at least 15 genera are reported from carbonate strata within the Cape Phillips Formation, Baillie-Hamilton Island. The collections are stratigraphically bounded by the graptolite Zones of Cyrtograptus murchisoni and Monograptus testis. The fauna is generically dominated by lichids, odontopleurids, and cheirurids. Scutelluids, phacopids, dalmanitids, and harpids are notable for their absence. At the familial level the fauna corresponds to one recently discovered from similar age beds of the Mackenzie Mountains, Northwest Territories. The limited quantity and fragmental nature of much of the silicified fauna precludes erection of many new taxa, although four new species described are: Sphaerexochus dimorphus, Dicranogmus skinneri, Hemiarges rohri, and Hemiarges mikulici. Dimorphic pygidia are interpreted as probable sexual dimorphs in Sphaerexochus dimorphus n. sp.

Llandovery graptolite biostratigraphy and paleobiogeography, Cape Phillips Formation, Canadian Arctic Islands

1989 ◽  
Vol 26 (9) ◽  
pp. 1726-1746 ◽  
Author(s):  
Michael J. Melchin
Keyword(s):  
North America ◽  
Canadian Arctic ◽  
The Arctic ◽  
Canadian Cordillera ◽  
Canadian Arctic Archipelago ◽  
The South ◽  
Cape Phillips Formation ◽  
Shallow Basin

Llandovery graptolites have been collected from 11 sections in the Cape Phillips Formation of the Canadian Arctic Archipelago: Melville, Bathurst, Truro, Cornwallis, Devon, and Ellesmere islands. The Cape Phillips Formation appears to have been deposited in a distinct subbasin, here termed the Cape Phillips Basin, under deep-shelf to shallow-basin conditions intermediate in position between the Arctic Platform to the south and east and the deeper Hazen Trough to the northwest.A total of 170 graptolite species and a further 25 subspecies have been identified. Their stratigraphic distribution allows the recognition of 11 graptolite zones: the acuminatus, atavus, acinaces, cyphus, curtus, convolutus, minor, turriculatus, crispus, griestoniensis, and sakmaricus zones. The curtus Zone can be subdivided into the pectinatus and orbitus subzones. The zones can be correlated with graptolite sequences worldwide.The Canadian Arctic faunas show strong affinities with those of Siberia, China, and the northern Canadian Cordillera. It may be possible to recognize a circum-equatorial faunal province in northern North America, Siberia, and China based on the occurrence of distinctive forms including Agetograptus and "Paramonoclimacis" in the middle Llandovery and certain Cyrtograptus species (especially C. sakmaricus) in the upper Llandovery.

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.

Wenlock (Silurian) graptolites, Cape Phillips Formation, Canadian Arctic Islands

1991 ◽  
Vol 82 (3) ◽  
pp. 211-237 ◽  
Author(s):  
A. C. Lenz ◽  
M. J. Melchin
Keyword(s):  
New Species ◽  
Canadian Arctic ◽  
Canadian Arctic Archipelago ◽  
Important Species ◽  
Cape Phillips Formation ◽  
Total Fauna

Twenty six of the more important species of monograptids (s.l.), retiolitids and Cyrtograptus (from a total fauna of 52 species) are described from Wenlock strata of the Cape Phillips Formation, Canadian Arctic Archipelago. Of this fauna, eight new species or subspecies, Monograptus firmus festinolatus, M. instrenuus, M. opimus, M. testis incomptus, Cyrtograptus falcatus, C. hamatus brevis, C. kolobus and C. pseudomancki, are described and illustrated.Wenlock biostratigraphic zones comprise the Cyrtograptus centrifugus-C. insectus Zone (earliest Wenlock), M. instrenuus-C. kolobus Zone, tentatively divisible into lower and upper subzones, C. perneri-M. opimus Zone possibly divisible into lower and upper subzones, C. lundgreni-M. testis Zone divisible into a lower M. testis incomptus Subzone and an upper M. testis testis Subzone, and the Pristiograptus ludensis Zone (latest Wenlock).

Silurian (Wenlock) calymenid trilobites from the Cape Phillips Formation, Central Canadian Arctic

1997 ◽  
Vol 71 (4) ◽  
pp. 657-682 ◽  
Author(s):  
Jonathan M. Adrain ◽  
Gregory D. Edgecombe
Keyword(s):  
New Species ◽  
New Taxa ◽  
Type Species ◽  
New Genus ◽  
Canadian Arctic ◽  
Canadian Arctic Archipelago ◽  
Cape Phillips Formation ◽  
Common Components

Calymenid trilobites are common components of diverse Silurian silicified faunas recovered from the Cape Phillips Formation of the Cape Phillips Basin, central Canadian Arctic Archipelago. Calymenids are represented in the Wenlock of the northern Laurentian region by only two genera, Diacalymene Kegel, 1927, and Arcticalymene new genus (type species A. viciousi new species). Calymenid diversity in any given fauna is never higher than two species, although these species may be numerically abundant. Arcticalymene became extinct during the Homerian, at which point calymenids disappeared forever from the northern Laurentian record.Other new taxa are Arcticalymene cooki new species, A. jonesi new species, A. matlocki new species, and A. rotteni new species. Material representing at least two more species of the new genus is reported in open nomenclature. Diacalymene gabrielsi Siveter and Chatterton, 1996, is recorded from the Cape Phillips Basin.

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