scholarly journals The Cheeneetnuk Limestone, an new Early(?) to Middle Devonian formation in the McGrath A-4 and A-5 quadrangles, west-central Alaska

10.14509/2258 ◽  
1983 ◽  
Author(s):  
R. B. Blodgett ◽  
W. G. Gilbert
Keyword(s):  
Middle Devonian ◽  
West Central

Two new Devonian spine-bearing pleurotomariacean gastropod genera from Alaska

1989 ◽  
Vol 63 (1) ◽  
pp. 47-52 ◽  
Author(s):  
Robert B. Blodgett ◽  
David M. Rohr
Keyword(s):  
Middle Devonian ◽  
New Genera ◽  
Early Devonian ◽  
Old World ◽  
West Central ◽  
Cool Temperate ◽  
Warm Temperate

Two new spine-bearing gastropods, Chlupacispira spinosa n. gen. and sp. and Spinulrichospira cheeneetnukensis n. gen. and sp., are described from the late Early Devonian (Emsian) and early Middle Devonian (Eifelian), respectively, of west-central Alaska. These represent the earliest reported spiny pleurotomariacean gastropods. Otherwise, spinose pleurotomariaceans are known from strata no older than Carboniferous age. Spinulrichospira cheeneetnukensis n. gen. and sp. appears to represent a more highly ornamented derivative of Ulrichospira Donald. Both new genera are part of the more highly ornamented fauna which occurred in warm equatorial waters of the Old World Realm during the Early and Middle Devonian, in contrast to more weakly ornamented shells of the Eastern Americas Realm and even more weakly ornamented (almost totally “plain”) shells of the Malvinokaffric Realm. The latter two realms are thought to represent subtropical to warm temperate and cool temperate to cool polar conditions, respectively.

A new species of Droharhynchia (Brachiopoda) from the lower Middle Devonian (Eifelian) of west-central Alaska

1994 ◽  
Vol 68 (6) ◽  
pp. 1235-1240 ◽  
Author(s):  
Mary E. Baxter ◽  
Robert B. Blodgett
Keyword(s):  
New Species ◽  
Middle Devonian ◽  
The Arctic ◽  
Geographic Proximity ◽  
Brooks Range ◽  
West Central ◽  
Arctic Alaska ◽  
Northern Alaska ◽  
A New Species

A new species of the genus Droharhynchia Sartenaer is established from lower Eifelian strata of west-central Alaska and the northwestern Brooks Range of Alaska. Droharhynchia rzhonsnitskayae n. sp. occurs in the Cheeneetnuk Limestone of the McGrath A-5 quadrangle, west-central Alaska, and the Baird Group of the Howard Pass B-5 quadrangle, northwestern Alaska. These occurrences extend the lower biostratigraphic range of both the genus and the subfamily Hadrorhynchiinae into the Eifelian. They also suggest close geographic proximity of the Farewell terrane of southwestern and west-central Alaska and the Arctic Alaska superterrane of northern Alaska during Devonian time.

Dutrochus, a new microdomatid (Gastropoda) genus from the Middle Devonian (Eifelian) of west-central Alaska

1993 ◽  
Vol 67 (2) ◽  
pp. 194-197 ◽  
Author(s):  
Robert B. Blodgett
Keyword(s):  
Middle Devonian ◽  
Equal Strength ◽  
West Central ◽  
The Family

A new gastropod genus, Dutrochus, is established for members of the family Microdomatidae that are characterized by a reticulate ornament of spiral cords and intersecting, finer collabral threads, with all but one spiral cord being of nearly equal strength, and the single remaining cord being of stronger (nearly twice the order) magnitude and being situated at the periphery. It is represented by the type and only known species, Dutrochus alaskensis n. gen. and sp., from the upper part (lower Middle Devonian; lower Eifelian) of the Lower? and Middle Devonian Cheeneetnuk Limestone, McGrath A-5 quadrangle, west-central Alaska. The genus is very close and nearly homeomorphic to the Permian microdomatid genus Glyptospira, but differs from the latter in possessing an extremely strong, peripheral spiral cord and an extremely thick, multi-layered apertural margin.

First recognition of the genus Verneuilia Hall and Clarke (Brachiopoda, Spiriferida) from North America (west-central Alaska)

1994 ◽  
Vol 68 (6) ◽  
pp. 1240-1242 ◽  
Author(s):  
Robert B. Blodgett ◽  
J. G. Johnson
Keyword(s):  
New Species ◽  
North America ◽  
Middle Devonian ◽  
Geographic Range ◽  
Good Evidence ◽  
Systematic Relationship ◽  
West Central ◽  
Internal Structures ◽  
First Time ◽  
A New Species

The brachiopod genus Verneuilia Hall and Clarke, 1893, is recognized for the first time in North America, where it is represented by a new species described here, V. langenstrasseni. This occurrence not only extends the geographic range of the genus, but also the lower age and stratigraphic limit into the Eifelian (early Middle Devonian). Previously, the oldest known species was the type, V. cheiropteryx d'Archiac and de Verneuil, 1842, from the Givetian (late Middle Devonian) of Germany. Internal structures of V. langenstrasseni n. sp. are similar to those of genera in the ambocoeliid subfamily Rhynchospiriferinae, providing the first good evidence of a systematic relationship.

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