BIOSTRATIGRAPHICALLY DIAGNOSTIC GRAPTOLITES ASSOCIATED WITH HINDE’S (1879) SCOLECODONTS

Innovative paleontologist George J. Hinde (1839–1918) greatly contributed to the research fields of conodonts and scolecodonts. In two important publications from 1879 he described such fossils of Ordovician through Carboniferous age. The Ordovician scolecodonts, and some of the conodonts, were all collected from the ‘Cincinnati group’ in the Toronto area. Based on these scolecodonts, Hinde (1879) erected many new species and three genera, Arabellites, Glycerites, and Oenonites, the names of which have been, and still are, debated. Thus, Hinde’s papers and type collections still are critical to students of scolecodonts, particularly for resolving nomenclatural and taxonomic problems.

During study of the Hinde (1879) Cincinnatian scolecodont type collection at the Natural History Museum, London, MEE discovered slabs with graptolites in abundance. These specimens are not described, but referred to as Diplograptus hudsonicus Nicholson, 1875, by Hinde. However, because D. hudsonicus is virtually unknown in the graptolite literature we questioned the validity of the name and whether Hinde had correctly identified the specimens. According to John Riva, D. hudsonicus actually is the senior synonym of the well-known species Climacograptus manitoulinensis Caley, 1936; now Amplexograptus manitoulinensis. However, since the former name had not been used in taxonomic descriptions for more than a century, Riva petitioned the ICZN in 1987 to have the name set aside as a nomen oblitum (Case 2596). The ICZN ruled in his favour (ICZN 1989, Opinion 1561) and now it is the name A. manitoulinensis that is valid, D. hudsonicus being merely its unavailable senior synonym.

After re-studying the graptoliferous slabs from the Hinde collection it became apparent that those graptolite specimens also are conspecific with A. manitoulinensis. Hence, because A. manitoulinensis is restricted to the zone of this name, the Cincinnatian scolecodonts (and conodonts) of Hinde, from the Toronto area, are from the A. manitoulinensis Zone. This interval includes the top of the Amorphognathus superbus through the base of the A. ordovicicus conodont zones and the upper Maysvillian to lower Richmondian North American stages.