Semitubina yukonensis new species, first occurrence of this biogeographically distinctive Old World Realm gastropod genus in the Lower Devonian of the western hemisphere

Abstract

Despite the rapidly expanding knowledge of Lower Devonian brachiopod faunas of the Western Cordillera of Canada (Lenz, 1976, 1977a, 1977b, 1982; Ludvigsen, 1970; Perry, 1984; Perry and Lenz, 1978; Perry et al., 1974, 1981), equivalent data on coeval gastropod faunas from this region are non-existent; to date, no publications have appeared in which gastropods have been described. Blodgett et al. (1988, table 1) provided faunal lists for two Lower Devonian localities in Western Canada: 1) Lochkovian-Emsian age collections from the Mackenzie Mountains, Northwest Territories, collected by the late D. G. Perry as part of his Ph.D. dissertation (Perry, 1984); and 2) an early Emsian collection from the Mt. Lloyd George area, British Columbia. We are currently examining the gastropod material recovered by A. C. Lenz from his richly diverse collections in the Royal Creek area, Yukon Territory, equivalent in age to those gathered by D. G. Perry from the Mackenzie Mountains. This note is the first of several papers focused on these paleobiogeographically significant faunas, and it is our desire to ultimately make clear the character of this Early Devonian province, which appears to include strata of British Columbia, Yukon and Northwest Territories, as well as the non-accreted portion of adjacent east-central Alaska.

Emsian (Lower Devonian) Rugosa of Nevada: Revision of Systematics and Stratigraphic Ranges, and Reassessment of Faunal Provincialism

“…Oliver and Pedder (1989) and Pedder and Oliver (1990), however, recognized a separate Emsian-Eifelian OWR Mackenzie Province based on coral genus presence/absence data. The Mackenzie coral province differs from the western Canada gastropod province proposed by Blodgett et al (2001) and Fryda et al (2002), only in that it did not originally include Pragian faunas. Qualitatively, Pragian and Emsian faunas of the Great Basin and Mackenzie provinces differ most strikingly in the absence from the Great Basin of any Mucophyllidae, Spongonariidae, or Ptenophyllidae, all well represented in the Mac kenzie Province, and by the presence in the Great Basin of nu merous species and genera of the Breviphyllidae (absent from the Mackenzie Province) and Papiliophyllidae (represented by a sin gle species known from one locality only in the Mackenzie Prov ince).…”

Jardamarekia enigma, a new Early Devonian tryblidioidean from Royal Creek area (Yukon Territory, Canada), and paleobiogeography of the Early Devonian of northwestern Canada

“…In our first contribution on Lower Devonian gastropods from Royal Creek, Yukon Territory (Blodgett et al 2001), we established the term "Western Canada Province" to comprise a biogeographic unit of provincial rank within the Old World Realm during the Early Devonian. The occurrence of the here described limpet, Jardamarekia enigma, belonging to a family hitherto known only from central Europe (Barrandian area, Czech Republic) is additional evidence supporting the Old World Realm character of Western Canada Province.…”

New porcellioidean gastropods from early Devonian of Royal Creek area, Yukon Territory, Canada, with notes on their early phylogeny

“…In our first contribution on Lower Devonian gastropods from Royal Creek, Yukon Territory, we established the term "Western Canada Province" to comprise a biogeographic unit of provincial rank within the Old World Realm (Blodgett et al, 2001) during the Early Devonian. The limits of this province included the miogeoclinal shelf areas of British Columbia, southwestern Northwest Territories, Yukon Territory, and the non-accretionary portion of Alaska (situated in the east-central part of the State in a triangular area bounded roughly on the northwest by Porcupine River and on the southwest by the Yukon River).…”

“…T HIS PAPER is our third contribution to the description of the diverse gastropod fauna found in Lower Devonian strata of the Royal Creek area, Yukon Territory (Blodgett et al, 2001;Fryda et al, 2002). These collections provide our first real glimpse into the biotic composition of Early Devonian gastropods from craton-bound strata of northwestern North America.…”