Carboniferous trilobites; utah species and evolution in North America
1969; Cambridge University Press; Volume: 43; Issue: 1 Linguagem: Inglês
ISSN
1937-2337
Autores Tópico(s)Evolution and Paleontology Studies
ResumoSystematic search of Mississippian and Pennsylvanian sections in Utah has pro- duced specimens of the following species: Proetus (Pudoproetus) missouriensis Shumard, Phillipsia tuberculata Meek & Worthen, Thigriffidest ameuroides Hessler, Richterella loganensis (Hall & Whitfield), Paladin chesterensis (Weller & Weller), Paladin retrolatus n. sp., Paladin mucronatus (Girty), Paladin morrowensis (Mather), Paladin pyriformus n. sp., Sevillia sevillensis Weller, Sevillia trinucleata (Herrick), Sevillia nucleata n. sp., Ditomopyge parvula (Girty), Ameura missouriensis (Shumard) (= Phillipsia (Grifithides?) sangamonensis Meek & Worthen, 1865), and Ameura major (Shumard). Sevillia nucleata n. sp. and additional specimens of Sevillia trinucleata (Herrick) are the basis for amending the genus Sevillia to include some forms without anterior borders. Great diversity and density of trilobite taxa characterize lower Mississippian sections in North America. Paladin is almost the only survivor across the Osagean-Meramecian bound- ary, and ultimately was the source for the Pennsylvanian genera Sevillia and Ameura. Grif- fithides survived until the earliest Meramecian but no later occurrences are known. Dito- moPbyge probably is a Pennsylvanian representative of the Griffithides lineage, however. Dis- tinction of Ditomopyge from a Paladin lineage is based most reliably on differences in meraspid and holaspid growth stages.
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