The Upper Ordovician trilobiteRaymonditesSinclair, 1944 in North America

Abstract

The Upper Ordovician (Sandbian–Katian) bathyurid trilobite Raymondites Sinclair is revised using new collections from Missouri and Ontario, and archival material from Illinois, Wisconsin, New York, and Ontario. Phylogenetic analysis supports monophyly of Raymondites, but recognition of this genus renders Bathyurus Billings paraphyletic. We treat Raymondites as a subgenus of Bathyurus and label the paraphylum of species traditionally assigned to the latter as Bathyurus sensu lato. Bathyurus (Raymondites) is composed of five previously named species, B. (R.) spiniger (Hall), B. (R.) longispinus (Walcott), B. (R.) ingalli (Raymond), B. (R.) bandifer Sinclair, and B. (R.) trispinosus (Wilson), and two new species, B. (R.) clochensis, and B. (R.) missouriensis; an eighth species is placed in open nomenclature. All species share tuberculate sculpture on the glabella, a relatively short palpebral lobe whose length is less than half of preoccipital glabellar length, and a pygidial outline that is well rounded posteriorly. Aside from the most basal species, B. (R.) longispinus, they also possess occipital spines and, where the pygidium is known, axial pygidial spines.

An echinoderm Lagerstätte from the Upper Ordovician (Katian), Ontario: taxonomic re-evaluation and description of new dicyclic camerate crinoids

“…Here, we use the most recent and widely accepted nomenclature for these units rather than their historical names. The Bobcaygeon Formation has replaced many units mentioned in older stratigraphic literature, including the Coboconk, Kirkfield, Rockland, Leray, and Hull formations (Liberty, 1969; Uyeno, 1974; Armstrong, 2000; see Swisher et al, 2015). The Kirkfield Formation of earlier workers is equivalent to the middle–upper Bobcaygeon Formation (Liberty, 1967, 1969; Brookfield and Brett, 1988; Brett and Taylor, 1999; Armstrong, 2000).…”

Paleocommunity composition, relative abundance, and new camerate crinoids from the Brechin Lagerstätte (Upper Ordovician)

“…Crinoids and other invertebrate fossils from the Brechin Lagerstätte are preserved in multiple horizons of Upper Ordovician rocks in the vicinity of Brechin, Ontario. Stratigraphic division and nomenclature for this region have been in flux for many years, and as a result, crinoids from the same or equivalent strata have been associated with multiple formation names, including the Hull, Kirkfield, Cobourg, Bobcaygeon, and Verulam formations (Liberty, 1969; Uyeno, 1974; Armstrong, 2000; see Swisher et al, 2015). Although the Bobcaygeon and Verulam formations have been the favored stratigraphic divisions in recent years (Armstrong, 2000), work by Paton and Brett (2019) suggested subdividing the Bobcaygeon into the Kirkfield and Coboconk formations and elevating the Bobcaygeon to a subcategory within the Simcoe Group.…”