The Chulitna terrane of south-central Alaska: A rifted volcanic arc caught between the Wrangellia composite terrane and the Mesozoic margin of North America

A well-prepared anterior half of an amiid skull from the Late Paleocene Paskapoo Formation of south-central Alberta is described. The specimen is either very closely related to, or conspecific with, Amia pattersoni Grande and Bemis, 1998, from the Early Eocene Green River Formation of Wyoming. We leave the specimen as Amia cf. pattersoni until additional material is found to further clarify its relationships. Amia cf. pattersoni is the oldest known specimen clearly identifiable as belonging to the genus Amia (sensu Grande and Bemis, 1998), and the Paskapoo species extends the known geographic range of Amia both northward and westward. The fish assemblage of the Paskapoo Formation represents the most diverse freshwater Paleocene fish fauna known from North America. Based on comparisons of sample size and relative taxonomic diversity to the better known Green River Formation localities of Wyoming, we predict that further collecting will substantially increase the known diversity of the Paskapoo fauna. The Paskapoo Formation, therefore, has great potential to continue adding to the meager knowledge of pre-Eocene freshwater teleost diversity in North America.

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Paleomagnetism of the Triassic Nikolai Greenstone, McCarthy Quadrangle, Alaska

Canadian Journal of Earth Sciences ◽

10.1139/e77-223 ◽

1977 ◽

Vol 14 (11) ◽

pp. 2578-2592 ◽

Cited By ~ 96

Author(s):

J. W. Hillhouse

Keyword(s):

British Columbia ◽

High Temperature ◽

North America ◽

Vertical Axis ◽

Upper Triassic ◽

Present Position ◽

Stable Component ◽

South Central ◽

Early Mesozoic ◽

Lamellar Texture

Paleomagnetic evidence indicates that the extensive early Mesozoic basalt field near McCarthy, south-central Alaska, originated far south of its present position relative to North America. Results obtained from the Middle and (or) Upper Triassic Nikolai Greenstone suggest that those basalts originated within 15° of the paleoequator. This position is at least 27° (3000 km) south of the Upper Triassic latitude predicted for McCarthy on the basis of paleomagnetic data from continental North America. The Nikolai pole, as determined from 50 flows sampled at 5 sites, is at 2.2° N, 146.1° E (α95 = 4.8°). The polarity of the pole is ambiguous, because the corresponding magnetic direction has a low inclination and a westerly declination. Therefore, the Nikolai may have originated near 15° N latitude or, alternatively, as far south as 15° S latitude. In addition to being displaced northward, the Nikolai block has been rotated roughly 90° about the vertical axis. A measure of the reliability of this pole is provided by favorable results from the following tests: (1) Within one stratigraphic section, normal and reversed directions from consecutive flows are antipolar. (2) Consistent directions were obtained from sites 30 km apart. (3) Application of the fold test indicated the magnetization was acquired before the rocks were folded. (4) The magnetizations of several pilot specimens are thermally stable up to 550 °C. The stable component is probably carried by magnetite with lamellar texture, a primary feature commonly acquired by a basalt at high temperature during initial cooling of the magma. Geologic and paleomagnetic evidence indicates that the Nikolai is allochthonous to Alaska and that, together with associated formations in southern Alaska and British Columbia, it is part of a now disrupted equatorial terrane.

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Historic Fire Regime of an Upland Oak Forest in South-Central North America

Fire Ecology ◽

10.4996/fireecology.0603045 ◽

2010 ◽

Vol 6 (3) ◽

pp. 45-61 ◽

Cited By ~ 29

Author(s):

Ryan D. DeSantis ◽

Stephen W. Hallgren ◽

David W. Stahle

Keyword(s):

North America ◽

Fire Regime ◽

Oak Forest ◽

South Central

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Wild Pigs in South-Central North America

Invasive Wild Pigs in North America ◽

10.1201/b22014-15 ◽

2019 ◽

pp. 347-368

Author(s):

Joshua A. Gaskamp ◽

James C. Cathey ◽

Billy Higginbotham ◽

Michael J. Bodenchuk

Keyword(s):

North America ◽

Wild Pigs ◽

South Central

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Arenig (Lower Ordovician) conodonts and biozonation in the eastern Siljan district, central Sweden

Journal of Paleontology ◽

10.1017/s0022336000034338 ◽

1994 ◽

Vol 68 (6) ◽

pp. 1350-1368 ◽

Cited By ~ 40

Author(s):

Anita M. Löfgren

Keyword(s):

North America ◽

The Other ◽

South Central ◽

Lower Ordovician ◽

Conodont Zone ◽

Local Base ◽

Reference Section ◽

Zones And Subzones

Based on biostratigraphic investigations in the eastern Siljan district, central Sweden, and combined with earlier studies at Hunneberg, south-central Sweden, it is shown that the early post-Tremadoc-age Paroistodus proteus conodont Zone can be divided into four successive subzones. These are, in ascending order: the Drepanoistodus aff. D. amoenus Subzone; the Tripodus Subzone; the Paracordylodus gracilis Subzone; and the Oelandodus elongatus-Acodus deltatus deltatus Subzone. The lowermost of the subzones is a concurrent range zone, with its reference section at Storeklev, Hunneberg, and the other three interval zones with the reference section at Sjurberg in the eastern Siljan district. Correlations between these two areas, as well as with the Flåsjö area, Jämtland, the Finngrundet core, and some other areas, are discussed, and it is concluded that the Drepanoistodus aff. D. amoenus Subzone and the Tripodus Subzone together correspond to the Megistaspis (Ekeraspis) armata trilobite Zone, and occur below the Hunnegraptus copiosus graptolite Zone. The Paracordylodus gracilis Subzone is equivalent with the lower part of the Megistaspis (Varvaspis) planilimbata trilobite Zone, and may correspond to the Hunnegraptus copiosus Zone. The uppermost subzone, the Oelandodus elongatus-Acodus deltatus deltatus Subzone, equals the upper part of the M. (V.) planilimbata Zone, and the local base of the Tetragraptus phyllograptoides graptolite Zone is close to the base of this conodont subzone. The last occurrences of T. phyllograptoides are close to the top of this conodont subzone. Also included in the investigation are the uppermost part of the uppermost Tremadoc Paltodus deltifer Zone and the conodont zones overlying the P. proteus Zone in the eastern Siljan district, the Prioniodus elegans Zone and the Oepikodus evae Zone; the latter zone corresponds to the trilobite zones of Megalaspides (M.) dalecarlicus and Megistaspis (Varvaspis) estonica. A few samples from the superimposed Baltoniodus triangularis, B. navis, and Paroistodus originalis Zones have been investigated and are described as well. The correlation of these conodont zones and subzones with those of areas outside Baltoscandia, particularly North America, is also discussed.

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Identifying areas of wetland and wind turbine overlap in the south-central Great Plains of North America

Landscape Ecology ◽

10.1007/s10980-020-01076-8 ◽

2020 ◽

Vol 35 (9) ◽

pp. 1995-2011

Author(s):

L. J. Heintzman ◽

E. S. Auerbach ◽

D. H. Kilborn ◽

S. M. Starr ◽

K. R. Mulligan ◽

...

Keyword(s):

North America ◽

Wind Turbine ◽

Great Plains ◽

The South ◽

South Central

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Amblyomma rotundatum (Koch, 1844) (Acari: Ixodidae) two-host life-cycle on Viperidae snakes

Revista Brasileira de Parasitologia Veterinária ◽

10.1590/s1984-29612010000300009 ◽

2010 ◽

Vol 19 (3) ◽

pp. 174-178 ◽

Cited By ~ 7

Author(s):

Daniel Sobreira Rodrigues ◽

Ricardo Maciel ◽

Lucas Maciel Cunha ◽

Romário Cerqueira Leite ◽

Paulo Roberto de Oliveira

Keyword(s):

Life Cycle ◽

North America ◽

Relative Humidity ◽

Total Duration ◽

Ixodid Tick ◽

Natural Conditions ◽

South Central ◽

Controlled Conditions ◽

In Captivity ◽

Host Life

Amblyomma rotundatum is an ixodid tick that infests ectothermic animals and reproduces exclusively by parthenogenesis. This tick has been frequently reported to infest reptiles and amphibians, under natural conditions and sometimes in captivity. It was described in Brazil and several other countries of South, Central and North America. Although many studies have reported aspects of its biology, none of them has used regularly either ophidian as hosts, or controlled temperature, humidity and luminosity for parasitic stages. The objective of this experiment was to study the life cycle of A. rotundatum feeding on Viperidae snakes under room controlled conditions at 27 ± 1 ºC temperature, 85 ± 10% relative humidity and 12:12 hours photoperiod for parasitic stages, and under B.O.D incubator conditions at 27 ± 1 ºC temperature, 85 ± 10% relative humidity and scotophase for non-parasitic stages. The total duration of the life cycle ranged from 56 to 163 days (mean of 105 days). Two-host life cycle was observed for most of the ixodid population studied.

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Late Cambrian ptychaspidid trilobites from western Utah: implications for trilobite systematics and biostratigraphy

Geological Magazine ◽

10.1017/s0016756805000543 ◽

2005 ◽

Vol 142 (4) ◽

pp. 377-398 ◽

Cited By ~ 14

Author(s):

J. M. ADRAIN ◽

S. R. WESTROP

Keyword(s):

North America ◽

Distinct Species ◽

Western North America ◽

Closely Related Species ◽

Widespread Species ◽

Late Cambrian ◽

South Central ◽

New Information ◽

The Family ◽

Notch Peak

The Notch Peak Formation (Late Cambrian, Sunwaptan) of western Utah yields diverse silicified trilobite faunas that provide new information on the anatomy of many taxa. The family Ptychaspididae Raymond, 1924, is represented by species of Keithiella Rasetti, 1944; Idiomesus Raymond, 1924; Euptychaspis Ulrich in Bridge, 1931; and Macronoda Lochman, 1964. At least four species are new, of which E. lawsonensis and M. notchpeakensis are named formally. Much previous work on Late Cambrian trilobites has emphasized biostratigraphic utility and the recognition of geographically widespread species. Data from new silicified collections indicate that this approach is difficult to justify because many putative ‘index species’ actually represent a plexus of closely related species whose biostratigraphic significance has yet to be determined. One such plexus is represented by E. kirki Kobayashi, 1935, whose previously reported occurrences in Texas, Oklahoma, Utah, Nevada and northern Canada record at least four distinct species. Similarly, Macronoda can now be shown to consist of at least five late Sunwaptan species in south-central and western North America.

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