Also known as Mina el Antimonium
Where: Sonora, Mexico (30.8° N, 112.6° W: paleocoordinates 6.6° N, 47.4° W)
• coordinate stated in text
• small collection-level geographic resolution
When: Tropites dilleri ammonoid zone, Lower Member (Antimonio Formation), Carnian (237.0 - 228.0 Ma)
• "Co-occurrence of the ammonoid Tropites subbullatus and the Sonoran ichthyosaur specimens was recognized by Smith in 1925 (King, 1939) and by Keller (1928). Smith additionally reported T. dilleri within the same layer. Working with faunas from the Hosselkus Limestone of Shasta County, California, Smith (1927) subdivided the T. subbullatus Zone into a lower "Trachyceras" Subzone and an upper" Juvavites" Subzone. These were changed, respectively, to the Dilleri Zone for the lower Upper Carian, and the Welleri Zone for the middle Upper Carnian (Silberling, 1956, 1959; Silberling and Tozer, 1968). The holotype of Shastasaurus altispinus was reported by Merriam (1908) as occurring in the "Trachyceras" beds (=present Dilleri Zone) of the Hosselkus Limestone in Shasta County. The presence of T. dilleri with UCMP 27141, 27142, and 27146 places them within the Dilleri Zone also; therefore, the holotype and the Sonoran specimens are both early Late Carnian in age."
• bed-level stratigraphic resolution
Environment/lithology: marine; lithified, red, sandy, calcareous mudstone
Size class: macrofossils
Collected by C. L. Baker in 1925; reposited in the UCMP
Primary reference: J. M. Callaway and J. A. Massare. 1989. Shastasaurus altispinus (Ichthyosauria, Shastasauridae) from the Upper Triassic of the El Antimonio District, northwestern Sonora, Mexico. Journal of Paleontology 63(6):930-939 [M. Carrano/H. Street]more details
Purpose of describing collection: general faunal/floral analysis
PaleoDB collection 102472: authorized by Matthew Carrano, entered by Hallie Street on 15.01.2011, edited by Jonathan Tennant
Creative Commons license: CC BY (attribution)
Taxonomic list
Reptilia | |
Toretocnemus californicus Merriam 1903 ichthyosaur | |
"Shastasaurus altispinus" = Shastasaurus pacificus
"Shastasaurus altispinus" = Shastasaurus pacificus Merriam 1895 ichthyosaur UCMP 27141; UCMP 27142; UCMP 27146
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