Erctella Monterosato, 1894

Colomba, Stella, Gregorini, Armando, Liberto, Fabio, Reitano, Agatino, Giglio, Salvatore & Sparacio, Ignazio, 2011, Monographic revision of the endemic Helix mazzullii De Cristofori & Jan, 1832 complex from Sicily and re-introduction of the genus Erctella Monterosato, 1894 (Pulmonata, Stylommatophora, Helicidae), Zootaxa 3134, pp. 1-42 : 16-18

Erctella Monterosato, 1894

Type species: Helix mazzullii De Cristofori & Jan, 1832 , by subsequent designation ( Pilsbry 1895: 316).

Shell ( Figs. 9–20 ). Dextral, medium-sized for a helicid (height 24–40 mm, maximum diameter 21–35 mm), globose-conical, light, uniformly yellowish or brownish, otherwise greenish for the presence of thin periostracum; sometimes with 3–5 brown spiral bands; external surface with thin growth lines, sometimes particularly wrinkled and with reticulated appearance; spire more or less elevated with 4–5 convex whorls, last whorl very large; aperture large, oval to round; sutures deep; umbilicus closed; peristome sharp, sometimes more or less thickened and/or reflected.

Animal. Yellow, sometimes with mantle border and foot lighter and head slightly darker, or entirely darker (Benoit 1857; Monterosato 1892).

Genitalia ( Figs. 21–23 ). General scheme of the semidiaulic monotrematic type (incomplete triaulic monotrematic: Visser 1977; Giusti et al. 1995), characterised by diverticulum of bursa copulatrix as long as duct of bursa copulatrix, or longer; two digitiform glands, each of which is distally divided into 11–45 slender and branched digit-like appendiges; vagina showing internally smooth and raised opening of free-oviduct, 4–8 small, raised, longitudinal pleats that disappear near dart-sac opening; a V-shaped pleat around dart-sac opening which continues with a little pilaster-shaped pleat ending in the genital atrium; penis of medium size, roundish; penial flagellum as long as penis and epiphallus together, or shorter; distal portion of penis internally divided into proximal and distal cavities by annular pad; proximal cavity with 14–20 longitudinal pleats, a small papilla on the internal wall and a very small penial papilla inside opening of proximal penis into distal penis; distal cavity smooth with a raised crestlike structure situated level with its opening into genital atrium. Inside the genital atrium is a characteristic bulge which is close to but separate from both the crest-like structure of the distal penis and the small pilaster-shaped pleat of the vagina.

Remarks. For differences characterizing Erctella with respect to the most closely related genera see Table 6 and the following dichotomous key to the genera Cantareus , Eobania, Cornu and Erctella .

1. Shell naticoid, uniformly yellowish, greenish or brownish, completely without bands. Proximal cavity of distal penis containing a rosette-like system of pleats which imitates or forms very small, true penial papilla. Thermophilic and sciaphilous genus more common on argillaceous and marly soils, that aestivates by hiding deep in the soil and closing its shell aperture with a robust epiphragm.............................................................................. Cantareus

- Shell not naticoid. Proximal cavity of distal penis containing very short, rosette-like penial papilla..................... 2

2. Shell globose to sub-globose-conical, somewhat depressed, creamy-white, usually with marked brown bands or single, diluted, flecked, pale-brown and covering upper surface of whorls, peristome markedly reflected. Proximal cavity of distal penis containing also a long and slender false penial papilla that surpasses the annular pad. Thermophilic genus with wide ecological valence, living in many different kinds of biotopes that aestivates by attaching itself by its paper-like epiphragm to rocks, walls, under surface of stones and other similar substrata................................................ Eobania

- Shell globose-conical, uniformly greenish-yellow or with reddish-brown spiral bands. Proximal cavity of distal penis containing smaller false penial papilla not reaching the annular pad.................................................... 3

3. Penis oblong; penial flagellum 3–5 times as long as epiphallus; crest-like structure in distal cavity of penis extended to fuse with a knob-like structure which arises at the end of a pilaster-shaped pleat on vagina wall; genus with wide ecological valence (occurring in many different kinds of biotopes).......................................................... Cornu

- Penis roundish; penial flagellum as long as penis and epiphallus together, or shorter; distal cavity of penis with a little crestlike structure separated by the little found pilaster-shaped pleat on vagina wall; just before the genital atrium there is also a robust and characteristic bulge of the internal wall of the distal cavity. Genus with exclusively rupicolous species... Erctella

Figures

FIGURES 9 – 11. Erctella mazzullii samples from various sites showing different morphotypes. Each shell shown in frontal (a) and dorsal (b) view. 9. Palermo, Monte Pellegrino, height (H): 30 mm, maximum diameter (D): 27 mm. 10. Palermo, Monte Pellegrino, H: 32 mm, D: 24 mm. 11. Palermo, Cinisi, Monte Pecoraro, H: 35 mm, D: 33 mm.

FIGURES 12 – 14. Erctella mazzullii samples from various sites showing different morphotypes. Each shell shown in frontal (a) and dorsal (b) view. 12. Palermo, Sferracavallo, la Montagnola, H: 29 mm, D: 28 mm. 13. Palermo, Cinisi, Monte Pecoraro, H: 36 mm, D: 34 mm. 14. Sine loco, Paleontological Museum of University of Catania (MPUC), Monterosato collection, Lot 1187, H: 31 mm, D: 30 mm, sinistral shell.

FIGURES 15 – 17. Erctella cephalaeditana samples from Cefalù, La Rocca showing different morphotypes. Each shell shown in frontal (a) and dorsal (b) view. 15. height (H): 30 mm, maximum diameter (D): 29 mm. 16. H: 31 mm, D: 26 mm. 17. H: 25 mm, D: 23 mm.

FIGURES 18 – 20. Erctella insolida samples from several sites of the Trapani province showing different morphotypes. Each shell shown in frontal (a) and dorsal (b) view. 18. San Vito lo Capo, Cala Mancina, height (H): 34 mm, maximum diameter (D): 30 mm. 19. Custonaci, Monte S. Giovanni, H: 37 mm, D: 34 mm. 20. San Vito lo Capo, Monte Passo del Lupo, H: 40 mm, D: 37 mm.

FIGURE 21. a. Erctella mazzullii from Monte Pellegrino, genitalia. b. Idem, internal structures shown. c. Erctella mazzullii from Monte Pecoraro, Genitalia with internal structure.

FIGURE 22. a. Erctella cephalaeditana from Cefalù, La Rocca, genitalia. b. Idem, internal structures shown.

FIGURE 23. a. Erctella insolida from Monte Cofano, genitalia. b. Idem, internal structures shown. c. Erctella insolida from San Vito lo Capo, Genitalia, internal structures shown.