Ausich et al.—Disparid and hybocrinid crinoids from the Brechin Lagerstätte


Billings, 1883; Eustenocrinus springeri Ulrich, 1925; Iocrinus trentonensis Walcott, 1883; and Isotomocrinus tenuis Billings, 1857b; and the hybocrinids Hybocrinus tumidus Billings, 1857a and Hybocystites problematicus Wetherby, 1880. Warn and Strimple (1977) recommended that D. kirki Ulrich, 1925 is a junior synonym of D. bellevillensis. We follow this recom- mendation. Hybocrinus pristinus Billings, 1858 is designated as a junior synonym of H. tumidus. The recommendation by Springer (1911) and the action by Parsley (1981), that Hybocystites eldonensis (Parks, 1908) is a junior synonym of Hybocystites problematicus, are followed. Although probably assignable to Anomalocrinus Meek and Worthen, 1865 (see also Guensburg, 1992), the aberrant crinoid Glaucocrinus falconeri Parks and Alcock, 1912 is designated a nomen dubium; Iocrinus similis (Billings, 1857a) is also designated a nomen dubium.


Geologic setting


Stratigraphic nomenclature for the Ordovician of southern Ontario has changed substantially with time, and today it remains unsettled. Further, outcrop versus subsurface nomen- clature is typically different. Herein, we primarily follow the outcrop lithostratigraphic nomenclature of Armstrong (2000). The new crinoid specimens considered herein are from the Lake Simcoe region and the Bobcaygeon and Verulam formations, which are part of the middle portion of the Lake Simcoe Group (the Lake Simcoe Group is equivalent to the Trenton and Ottawa groups, see Armstrong, 2000). The middle and upper Bobcaygeon Formation and the lower Verulam Formation are Late Ordovician (Katian) in age (Brookfield and Brett, 1988; Holland and Patzkowsky, 1996; Sproat et al., 2015). Older literature reports crinoids from the Kirkfield, Hull,


and Cobourg units. The Hull Formation of previous workers is now considered equivalent to the upper Bobcaygeon Formation. Similarly, the Kirkfield Formation of previous workers is now considered equivalent to the middle–upper Bobcaygeon Formation. The Cobourg beds of previous workers is now considered equivalent to the lower member of the Lindsay Formation, which is superjacent to the Verulam Formation. For further discussion of the stratigraphic nomenclature, sedimentology, taphonomy, and history of the study of the Brechin Lagerstätte, see Cole et al. (2018).


Materials and methods


Localities.—New material reported herein was collected from active quarries. With specimens recovered from blast piles, the upper Bobcaygeon-Verulam Formation boundary interval is commonly the most precise stratigraphic placement possible, because this is the fossiliferous part of the section. More precise stratigraphic data are given where possible. All material is from the vicinity of Brechin, Ontario, Canada. Quarries from which new crinoids from the J.M. Koniecki collection were recovered include the Carden Quarry (44°34'33.5''N, 79°06'09.5''W), located 6 km east of the town of Brechin; the LaFarge Quarry (44°31'55.9''N, 79°09'47.8''W), located 2 km southeast of Bre- chin; and the Tomlinson Quarry (44°35'45.9''N, 79°05'70.4''W), located 14 km northeast of Brechin. Additional material is from


851


Figure 1. Location map with position of various quarries in the Lake Simcoe region of southern Ontario from which crinoids of the Brechin Lagerstätte are known: (1) southern Ontario with study area in box; (2) relative position of collection sites (stars) within the study area. Modified from Cole et al. (2018).


the James Dick Quarry (44°29'93.7''N, 79°09'61.6''W). Material from the Carden and LaFarge quarries was recovered from an unconstrained interval including ~15mof upper Bobcaygeon and 5 m of lower Verulam (hereafter referred to as the ‘Bobcaygeon- Verulam contact zone’); material from the Tomlinson Quarry is from the upper Bobcaygeon; and material from the James Dick Quarry is from the lower Verulam. Older collections in the Lake Simcoe region are predominately from the upper Bobcaygeon of the classic Kirkfield Quarry (44°35'06.32''N, 78°58'08.16''W), which is now flooded and inaccessible (Fig. 1).


Repositories and institutional abbreviations.—New specimens for this study are deposited in the University of Michigan Museum of Paleontology (UMMP). Depository of other specimens considered here include:BMNH, Burpee Museum of Natural History, Rockford, Illinois, USA; CMC IP, Cincinnati Museum Center Invertebrate Paleontology Collections, Cincinnati, Ohio, USA; GSC, Geological Survey of Canada, Ottawa, Canada; MCZ, Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts, USA; ROM, Royal Ontario Museum, Toronto, Canada; USNM S, Springer Room, National Museum of Natural History, Washington, DC, USA.


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