Additional information on the identity of Clavatula quinteni Nolf & Verstraeten, 2006 and Clavatula xanteni Nolf & Verstraeten, 2006 with a link towards more twin species, pp. 1-33, text figures 1-4, pls. I-XIX, by Frank Nolf.
This paper is an answer to vague allegations about the identity of Clavatula quinteni and C. xanteni, both described eight years ago, made by two colleagues in the sister magazine ’Xenophora’. The underlying reason of this confusing and irrational act is revealed, a thorough comparison of the two is made resulting in a link to similar problems with regard to identifying twin species.
Keywords: Clavatula quinteni, C. xanteni, Callumbonella suturale, Laevicardium crassum, Laevicardium oblongum, Fusinus mollis, Fusinus albinus, Gibbula pennanti, Gibbula umbilicalis, twin species.