Page 2 - Colomba-et-al-2011-Erctella-mazzullii-complex-Zootaxa-3134

Introduction

Helix mazzullii De Cristofori & Jan, 1832 is currently considered a single endemic species of northwestern Sicily
ranging from Cefalù (Palermo province) to the mountains near Trapani (Alzona 1971; Cesari 1978; Manganelli et
al. 1995) (Fig. 1). Its restricted distribution range and peculiar biology (it is rupicolous and saxicavous) make it one
of the most vulnerable and interesting groups among Mediterranean Helicidae (Manganelli et al. 2000).

Helix mazzullii shows a high variability in shell morphology which led several authors of the 19th century to
establish numerous nominal taxa for these animals.

In the past, Helix mazzullii has been included in the genus Helix Linné and various other genus group taxa,
such as Helicogena Férussac, Cantareus Risso, Cryptomphalus Moquin-Tandon and Erctella Monterosato. Giusti
et al. (1995) and Manganelli et al. (1995), taking into account its genital morphology, elevated Cantareus to genus
rank (instead of a subgenus of Helix), including C. aspersus, C. mazzullii and C. apertus. Other authors maintained
Cantareus for apertus whereas aspersum and mazzullii were included within the genus Cornu Born, 1778 (see
Bank et al. 2001). This choice, however, raised nomenclatural concerns, since Cornu was introduced by Born
(1778) as Cornu copiae, based on a teratological specimen of Helix aspersa O.F. Müller. Because, according to
ICZN (1985, Article 1b(2) [equivalent with ICZN 1999 Art. 1.3.2], teratological specimens as such are excluded
from the provisions of the code, Cornu was rejected as an available genus name by some authors (e.g., Giusti et al.
1995). However, Gerber (2000) argued that “because it was not proven that Born used the name Cornu copiae in
1778 under the conscience and with the intent to describe a teratological specimen [i.e., “as such”] ICZN (1985)
Art. 1b(2) does not apply and Cornu thus is an available genus name”. This conclusion was supported by Falkner et
al. (2001). Currently, although the issue is still contentious, most systematists (e.g., Bank et al. 2001; Ketmaier et
al. 2007; Bank 2009) accept these species as Cantareus apertus, Cornu aspersum and Cornu mazzullii.

FIGURE 1. Geographic distribution of Erctella species in northwestern Sicily. = E. insolida; = E. mazzullii; = E. cepha-
laeditana.

2 · Zootaxa 3134 © 2011 Magnolia Press COLOMBA ET AL.