New Middle Silurian hexactinellid sponge from the Mackenzie Mountains, Northwest Territories, Canada

1994 ◽  
Vol 68 (2) ◽  
pp. 218-223 ◽  
Author(s):  
J. Keith Rigby ◽  
Brian D. E. Chatterton
Keyword(s):  
New Species ◽  
Northwest Territories ◽  
Type Species ◽  
Third Order ◽  
First Order ◽  
The Road ◽  
Dermal Layer ◽  
Hexactinellid Sponge ◽  
Mackenzie Mountains

Several specimens of the small hexactinellid, Cyathophycus mackenziensis n. sp., were collected from pale brown, shaly mudstone of the Road River Formation. The sponges are of Wenlock age and were collected from near Avalanche Lake, Mackenzie Mountains, Northwest Territories, Canada. The small, steeply obconical sponges have skeletons in crudely ranked quadrules to at least third-order, with first-order openings generally 2 mm high and 1 mm wide. Successive orders decrease in stages approximately half that of larger elements. A moderately irregular dermal(?) layer with circular parietal gaps is suggested in some specimens. The new species is consistently finer textured than either the type species Cyathophycus reticulatus Walcott, 1879, or the later described Cyathophycus quebecensis Dawson, 1889.

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.

Systematics of Encrinuroides and Curriella (Trilobita), with a new Early Silurian encrinurine from the Mackenzie Mountains

1990 ◽  
Vol 27 (6) ◽  
pp. 820-833 ◽  
Author(s):  
Gregory D. Edgecombe ◽  
Brian D. E. Chatterton
Keyword(s):  
New Species ◽  
Northwest Territories ◽  
Type Species ◽  
Taxonomic Revision ◽  
Sister Group ◽  
Consistency Index ◽  
Parsimony Analysis ◽  
Type Specimens ◽  
Mackenzie Mountains

Encrinuroides Reed, 1931 has been diagnosed as a paraphyletic ancestral taxon since its inception. Cladistic parsimony analysis of "Encrinuroides" species most closely related to the Silurian Encrinurus plexi discovers two shortest-length cladograms (consistency index = 0.68) based on 28 exoskeletal characters. Curriella Lamont, 1978 is revised to include Curriella clancyi n.sp., based on silicified material from earliest Llandovery strata of the Whittaker Formation in the Mackenzie Mountains, Northwest Territories. The new species is most closely related to the Scottish Llandovery type species, Curriella newlandensis Lamont, 1978 (for which type specimens are figured) and Curriella tuberculifrons (Weller, 1907) from Illinois. This Silurian clade is sister group to stratigraphically early Chinese "Encrinuroides" species and the monophyletic Encrinurus plexi. Certain Appalachian Caradoc taxa and Erratencrinurus Krueger, 1972 are more closely related to this group than to many other "Encrinuroides" spp. Further taxonomic revision should exclude these species from Encrinuroides (s.s.), which can be appreciably restricted in scope.

The sequence and correlation of Early Ordovician (Arenig) graptolite faunas in the Richardson Trough and Misty Creek Embayment, Yukon Territory and District of Mackenzie, Canada

2006 ◽  
Vol 43 (12) ◽  
pp. 1791-1820 ◽  
Author(s):  
D E Jackson ◽  
A C Lenz
Keyword(s):  
Northwest Territories ◽  
Deep Water ◽  
Yukon Territory ◽  
Early Ordovician ◽  
The Road ◽  
Bedded Chert ◽  
First Occurrence ◽  
Mackenzie Mountains ◽  
First Time

Four graptolite biozones are recorded from the Arenig portion of the Road River Group in the Richardson and Mackenzie mountains in the Yukon and Northwest Territories. In ascending order, these zones are Tetragraptus approximatus, Pendeograptus fruticosus, Didymograptus bifidus, and Parisograptus caduceus australis (new). The Castlemainian stage may be represented by nongraptolitic massive bedded chert. The Arenig–Llanvirn boundary is drawn below the first occurrence of Undulograptus austrodentatus. Fifty-four graptolite taxa are present, and 16 of these species and subspecies are recorded for the first time in this deep-water biotope, namely, Didymograptus? cf. adamantinus, D. asperus, D. dilatans, D. cf. kurcki, D. validus communis, Holmograptus aff. leptograptoides, H. sp. A, Isograptus? sp. nov. A, I. ? dilemma, Keblograptus geminus, Pseudisograptus manubriatus harrisi, Ps. m. koi, Ps. m. janus, Ps. cf. tau, Xiphograptus lofuensis, and Zygograptus cf. abnormis.

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.

Late Ordovician and Silurian lichid trilobites from northwestern Canada: Hemiarges, Borealarges, and Richterarges

2007 ◽  
Vol 81 (6) ◽  
pp. 1348-1364 ◽  
Author(s):  
Margaret J. Campbell ◽  
Brian D. E. Chatterton
Keyword(s):  
Phylogenetic Analysis ◽  
New Species ◽  
Northwest Territories ◽  
Late Ordovician ◽  
The Arctic ◽  
Mackenzie Mountains ◽  
One New Species

Four new species of Borealarges, B. fritillus, B. patulus, B. renodis, and B. variabilis, and one new species of Richterarges, R. facetus, are described and one unnamed species, Borealarges sp., discussed. All are from the Wenlock strata of Avalanche Lake sections in the Mackenzie Mountains, Northwest Territories. Borealarges tuckerae Adrain, 1994, the only species reported from both the Arctic and the Mackenzie Mountains, is discussed. Hemiarges avalanchensis n. sp., an Ashgill species from Avalanche Lake section AV 4B just below the Ordovician-Silurian boundary, is described. A phylogenetic analysis based on 14 species of Borealarges, three of Richterarges, and two of Hemiarges, demonstrates that the former two genera are three separate and distinct taxa. Borealarges, a genus that includes some species formerly assigned to Richterarges or Hemiarges, is monophyletic, contains a well-supported internal clade of species, and is not separated into senso stricto and senso lato groupings.

Nadiastrophia from the Headless Formation (Eifelian), Mackenzie Mountains, District of Mackenzie, Northwest Territories

1973 ◽  
Vol 10 (9) ◽  
pp. 1460-1464 ◽  
Author(s):  
A. C. Lenz
Keyword(s):  
New Species ◽  
Northwest Territories ◽  
Middle Devonian ◽  
Southeastern Pacific ◽  
Mackenzie Mountains ◽  
A New Species

The genus Nadiastrophia previously recorded only from Australia and China, is described from the Headless Formation of the Mackenzie Mountains. This discovery further emphasizes the early Middle Devonian faunal affinities between the Cordilleran and southeastern Pacific regions. The Mackenzie Mountains Nadiastrophia is assigned to a new species, N. mackenziensis.

scholarly journals New records of Burgess Shale-type taxa from the middle Cambrian of Utah

2015 ◽  
Vol 89 (3) ◽  
pp. 411-423 ◽  
Author(s):  
Simon Conway Morris ◽  
Paul A. Selden ◽  
Glade Gunther ◽  
Paul G. Jamison ◽  
Richard A. Robison
Keyword(s):  
New Species ◽  
North America ◽  
Northwest Territories ◽  
Type Species ◽  
New Records ◽  
Western North America ◽  
Burgess Shale ◽  
Middle Cambrian ◽  
Stem Group ◽  
A New Species

AbstractCambrian strata of the Laurentian craton contain numerous examples of Burgess Shale–type faunas. Although displaying a more or less concentric distribution around the cratonal margin, most faunal occurrences are in present-day western North America, extending from the Northwest Territories to California. Nevertheless, the soft-bodied and lightly skeletalized fossils in most of these Lagerstätten are highly sporadic. Here, we extend knowledge of such Middle Cambrian occurrences in Utah with reports of four taxa. An arthropod from the Marjum Formation, Dytikosicula desmatae gen. et sp. nov., is a putative megacheiran. It is most similar to Dicranocaris guntherorum, best known from the younger Wheeler Formation, but differs primarily in the arrangement of pleurae and overall size. Along with a specimen of ?Yohoia sp, a new species of Yohoia, Y. utahana sp. nov., is described. It differs from the type and only known species, Y. tenuis, principally in its larger size and shorter exopods; it is the first description of this genus from outside the Burgess Shale. A new species of a stem-group lophotrochozoan from the Spence Shale, Wiwaxia herka sp. nov., possesses a palisade of dorso-lateral spines that are more robust and numerous than the type species of Wiwaxia, W. corrugata. Another notable taxon is Eldonia ludwigi from the Marjum Formation, which is interpreted as a primitive ambulacrarian (assigned to the cambroernids) and a new specimen of the ?cnidarian Cambrorhytium from the Wheeler Shale is illustrated.

The aulacopleurid trilobite Otarion, with new species from the Silurian of northwestern Canada

1994 ◽  
Vol 68 (2) ◽  
pp. 305-323 ◽  
Author(s):  
J. M. Adrain ◽  
B. D. E. Chatterton
Keyword(s):  
New Species ◽  
Northwest Territories ◽  
Morphological Change ◽  
Sister Group ◽  
Sister Group Relationship ◽  
Distinctive Pattern ◽  
Single Section ◽  
History Of ◽  
Mackenzie Mountains ◽  
Stratigraphic Succession

The genus Otarion Zenker, 1833, first appears in the Wenlock simultaneously with Cyphaspis Burmeister, 1843, as the oldest known species of each occur together in the southern Mackenzie Mountains of the Canadian Northwest Territories. The genera are unambiguous sister groups, a relationship supported most compellingly by a uniquely derived and distinctive pattern of juvenile cephalic spines, shared also with the Carboniferous genus Namuropyge Richter and Richter, 1939. This sister group relationship permits the development of a robust and stratigraphically correlated hypothesis of relationship among the adequately known species of Otarion, Otarion, Cyphaspis, and Namuropyge constitute the tribe Otarionini. The Mississippian genus Dixiphopyge Brezinski, 1988, may also belong to Otarionini. Namuropyge is a paedomorph, likely derived from a Degree Six or Seven meraspid of an older species of uncertain position in the Otarion–Cyphaspis clade.Three Wenlock species of Otarion occur in stratigraphic succession in a single section in the Mackenzie Mountains. Analysis of morphological change with time, and of sequential ontogenies, suggests that the Silurian history of the genus was dominated by incidents of peramorphosis.New species are Otarion huddyi, O. beukeboomi, and O. coppinsensis. Otarion brauni Perry and Chatterton, 1979, is revised.

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.

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