Some Cocconeis species (Bacillariophyceae) originally described by William Gregory and Robert Kaye Greville from the Firth of Clyde and Loch Fyne (Scotland)
Riaux-Gobin, Catherine; Compère, Pierre; Ector, Luc
Several marine diatoms (Bacillariophyceae) were described from the Firth of Clyde and Loch Fyne (Scotland) among which 12 Cocconeis species by William Gregory in 1855–1857, with two additional species by Robert Kaye Greville in 1859. Five Gregory's original slides 'Arran57' (Greville's slide collection, housed in the Natural History Museum, BM) from Lamlash Bay (Arran Island, Firth of Clyde) were examined and several taxa marked by Greville (diamond circle on the cover slip and quotation on the label of these slides) are re-investigated: i.e., Cocconeis arraniensis Greville, Cocconeis distans W. Gregory, Cocconeis nitida W. Gregory, Cocconeis ornata W. Gregory and Cocconeis pseudomarginata W. Gregory. These species have been originally incompletely described by Gregory (1855–1857) and Greville (1859) and their illustrations by Greville are not always fully informative. Some ambiguity can be noted about species showing similarities in their morphology but likewise present in the material: i.e., C. ornata and Cocconeis quarnerensis (Grunow) A.W.F.Schmidt; i.e., C. distans, C. nitida and Cocconeis gregoryi sp. nov. Since the original raw material used by Gregory for the 'Arran57' slides was not found in BM, no scanning electron microscope observation of the material has been possible. Nevertheless, modern light microscopy permits to accurately focus on the striation and other features of the valves marked by Greville and to complete the original description and iconography of several taxa.