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.

Silurian Odontopleurinae (Trilobita) from the Cape Phillips Formation, Arctic Canada

1997 ◽  
Vol 71 (2) ◽  
pp. 237-261 ◽  
Author(s):  
Jonathan M. Adrain ◽  
Lars Ramsköld
Keyword(s):  
New Species ◽  
Northwest Territories ◽  
Type Species ◽  
Cladistic Analysis ◽  
Canadian Arctic ◽  
Stratigraphic Sequence ◽  
Phylogenetic Pattern ◽  
Previous Hypothesis ◽  
Cape Phillips Formation ◽  
Mackenzie Mountains

Odontopleurids are a diverse component of rich silicified trilobite faunas recovered from the Wenlock and Ludlow of the Cape Phillips Formation, central Canadian Arctic. Odontopleurinae and Acidaspidinae are common, but Ceratocephalinae and Koneprusiinae are also represented. This work treats all of the Odontopleurinae, with the exception of the genus Acanthalomina Prantl and Přibyl, 1949.New species of Kettneraspis Prantl and Přibyl, 1949, include the upper Sheinwoodian K. wrightae, the lower Homerian K. lindoei, and the Gorstian K. caldwelli. Rare specimens assigned to Odontopleura Emmrich, 1839, and Radiaspis Richter and Richter, 1917, occur in the Sheinwoodian of the central Arctic.Edgecombeaspis (type species E. johansonae new species) is proposed for an odontopleurine clade endemic to Laurentia, and in the Silurian restricted to northern Laurentia. Cladistic analysis yields a hypothesis of ingroup structure that is in general calibrated with stratigraphic sequence. An exception is a group of Telychian species from the Mackenzie Mountains, whose stratigraphic sequence was used to support a previous hypothesis of an ancestral-descendant lineage. The cladistic result indicates that the stratigraphic pattern is the inverse of the phylogenetic pattern: the stratigraphically lowest species in the proposed lineage is the most derived, and the highest is most primitive. In addition to the type, new species of Edgecombeaspis include the mid-Sheinwoodian E. jahansi and the lower Homerian E. soehni. Edgecombeaspis apparently became extinct in the Homerian.The species Kettneraspis lenzi (Chatterton and Perry, 1983) and Radiaspis cf. R. norfordi (Chatterton and Perry, 1983) occur in the central Arctic, and further strengthen previous correlations with strata in the central Mackenzie Mountains, Northwest Territories.

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.

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).

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.

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.

The otarionine trilobites Harpidella and Maurotarion, with species from northwestern Canada, the United States, and Australia

1995 ◽  
Vol 69 (2) ◽  
pp. 307-326 ◽  
Author(s):  
Jonathan M. Adrain ◽  
Brian D. E. Chatterton
Keyword(s):  
United States ◽  
New Species ◽  
Northwest Territories ◽  
Middle Devonian ◽  
The United States ◽  
Upper Ordovician ◽  
Mackenzie Mountains ◽  
New Diagnosis

Maurotarion Alberti, 1969, is a diverse otarionine clade that can be readily distinguished from Harpidella M'Coy, 1849. Both genera appear in the Upper Ordovician and range until the Middle Devonian. A new diagnosis for each taxon is given. New species of the genera from the Ordovician and Silurian of the central Mackenzie Mountains, Northwest Territories, Canada, include Harpidella kurrii (Ashgill), H. tikkaneni (Llandovery), H. greggi (Wenlock), and Maurotarion messieri (Llandovery). Harpidella megalops (M'Coy, 1846), H. triloba (Hu, 1975), H. spinafrons (Williams in Cooper and Williams, 1935), Maurotarion struszi (Chatterton, 1971), and M. instita (Whittington and Campbell, 1967) are revised.

Phylogenetic analysis of some Silurian rostroconchs (Mollusca) from northwestern Canada

1995 ◽  
Vol 32 (6) ◽  
pp. 806-827 ◽  
Author(s):  
Michael W. Caldwell ◽  
Brian D. E. Chatterton
Keyword(s):  
Phylogenetic Analysis ◽  
New Species ◽  
Sexual Dimorphism ◽  
Northwest Territories ◽  
Preliminary Analysis ◽  
New Genus ◽  
Data Sets ◽  
Familial Relationships ◽  
Mackenzie Mountains ◽  
Using Data

The new genus Avalanchia and the new species Avalanchia pterocarina, Cassowarioides anisomorpha, Cassowarioides polgari, Nehedia bergeraci, Nehedia restricta, and Nehedia tricarina are proposed from exceptionally preserved silicified faunas. Two new but unnamed rostroconch species are also described. These conocardioid rostroconchs were collected from Silurian deposits (late Llandovery to early Ludlow) near Avalanche Lake in the Mackenzie Mountains, Northwest Territories, Canada, and, when added to global rostroconch faunal lists, indicate a previously unrecognized diversity of Silurian conocardioid rostroconchs. The morphology of conocardioid rostroconchs is discussed, and a glossary of terms presented. Sexual dimorphism is recognized in species of Cassowarioides. Phylogenetic analysis of hippocardiids and bransoniids supports the monophyly of several genera. The hippocardiid genus Bigalea Pojeta and Runnegar, 1976, is recognized as paraphyletic and three species are assigned to a new genus, Redstonia. Preliminary analysis of bransoniids and hippocardiids for familial relationships, using data sets from the within-family analyses, indicates that the Bransoniidae is polyphyletic. The generic complex Mulceodens, considered to be derived bransoniid, is consistently reconstructed within a clade of derived hippocardiids.

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.

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