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A new genus of dimeropygid trilobites from the Great Basin of the western USA

Dimeropygidae Hupé, 1953 is a family of highly vaulted and small trilobites from the paleotropics of the uppermost Cambrian through the Ordovician. Specimens are known from Laurentia, Baltica, Avalonia, Siberia, Australia, North China, and South China. Dimeropygids are difficult to recover because of their small size and vaulted, tuberculate, and often spiny exoskeletons. Thus, most of their diversity is known from secondarily silicified material which preserves remarkable amounts of detail on the sclerites. Such faunas, while often rare, are common in the Great Basin of the western USA.
Trilobite research has been conducted in the Great Basin has been since the late 1800s. Recent high intensity sampling and collection of larger sample sized from silicified horizons has increased the known diversity of trilobites from Lower Early Ordovician. New collections from the Lower Ordovician are providing crucial new insight into the groups early evolutionary history (e.g., Adrain & Westrop, 2007, McAdams & Adrain, 2009, Adrain et al., 2014a). Skullrockicurus n. gen. is a new genus of dimeropygid trilobites including at least seven new species. Five of the new species are well known enough from silicified material to formally name: S. greeni (Garden City Formation, Idaho and House Formation, Utah), S. plummeri (House Formation, Utah), S. judyi (House Formation, Utah), S. massarellai (House Formation, Utah), and S. brocki (House Formation, Utah). Synapomorphies of the new genus include four pairs of tubercles on the glabella, a posteriorly bowed glabella, long preglabellar field, and semilunate pygidium with a corona of tubercles or spines at the fulcrum.

Identiferoai:union.ndltd.org:uiowa.edu/oai:ir.uiowa.edu:etd-7746
Date01 May 2018
CreatorsLosso, Sarah
ContributorsAdrain, Jonathan M.
PublisherUniversity of Iowa
Source SetsUniversity of Iowa
LanguageEnglish
Detected LanguageEnglish
Typethesis
Formatapplication/pdf
SourceTheses and Dissertations
RightsCopyright © 2018 Sarah Losso

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