Massylaea constantina (E. Forbes, 1838)

Bouaziz-Yahiatene, Houria, Pfarrer, Beat, Medjdoub-Bensaad, Ferroudja & Eike Neubert,, 2017, Revision of Massylaea Moellendorff, 1898 (Stylommatophora, Helicidae), ZooKeys 694, pp. 109-133 : 115-118

Massylaea constantina (E. Forbes, 1838) Figs 9, 10-12

Helix constantina E. Forbes, 1838; Annals of Natural History, II: 251, pl. XI, fig. 1 [In waste places among nettles at Bougia].

Helix cirtae Terver, 1839; Catalogue des Mollusques...: 11, pl. 1, fig. 1 [Bone].

Helix constantinae var. bifasciata Bourguignat, 1863; Malacologie de l’Algérie I: 114 [La Calle].

Helix constantinae var. conoidea Bourguignat, 1863; Malacologie de l’Algérie I: 114, plate 10 fig. 7 [Constantine].

Helix constantinae var. depressa Bourguignat, 1863; Malacologie de l’Algérie I: 114 [Ouled-Sultan].

Helix constantinae var. maxima Bourguignat, 1863; Malacologie de l’Algérie I: 114 [Constantine].

Helix constantinae var. minima Bourguignat, 1863; Malacologie de l’Algérie I: 114 [Bone].

Helix constantinae var. trifasciata Bourguignat, 1863; Malacologie de l’Algérie I: 114 [La Calle].

Type specimens.

constantina : no type specimens could be identified in the E. Forbes collection in NMSZ; cirtae : syntype MHNL 45001107; the type specimens for the varietal names of Bourguignat are not identifiable in his collection.

Additional specimens.

Ighil Bourmi, 36.4872 4.0613, 1297 m alt., 24.5.2015, Bouaziz, NMBE 540545/1, Makouda, Tizi Ouzou/ Kabylie, 36.7909 4.0659, 440 m alt., 22.3.2015, Bouaziz, NMBE 540543/3, Azaghar, Bounouh, Tizi Ouzou, 36.5214 3.9425, 432 m alt., 26.4.2015, Bouaziz, NMBE 540542/9, Draa Ben Khedaa/ Tizi Ouzou, 36.7318 3.9654, 50 m alt., 6.1.2015, Bouaziz, NMBE 534211/20.

Diagnosis.

Medium sized shell, teleoconch smooth, and aperture with a raised columellar ridge.

Description.

Shell medium sized, with a globular or broad conical spire, basic colour white to grey, always with up to five brown spiral bands; protoconch large (diameter ca. 4 mm), white; all teleoconch whorls regularly increasing, with the last whorl rapidly declining at the aperture; suture of moderate depth, surface of teleoconch smooth; usually with five spiral bands with spiral 2+3 often very close or almost merging; aperture always porcelain white with a thick lip, columellar part of aperture with a raised ridge; peristome slightly thickened, umbilicus completely covered by a large reflection of the columellar part of aperture.

Genital organs (Fig. 9 A–C): penis subdivided in three parts, with an elongate distal tube connecting to the atrium, and a bilobed muscular proximal part with the internal boundary marked by an annular pad ( Giusti et al. 1995); epiphallus longer than penis, enveloped by a strong penial retractor muscle that connects with a fascicle to the atrium, flagellum a long, simple tube; internally, the proximal penial chamber filled by a solid penial papilla (pp2, see also Neubert & Bank 2006); epiphallus opening into the penial chamber via a small pore.

Dart sac opening laterally into the short vagina; glandulae mucosae with two central stems giving rise to at least three subsequent branches with at least 40 tubules; diverticulum branches off in a central position from the pedunculus reaching a length of at least 30 mm.

Measurements: syntype cirtae : H = 21.3 mm; D = 27.2 mm; PH = 8.6 mm; PD = 12.9 mm; W = 4.75.

Distribution.

This species is known from Tizi Ouzou in the Grand Kabylie towards the northern parts of the province of Constantine. In many places it lives in sympatry with M. vermiculata .

Remarks.

This species proved to be quite stable in terms of conchological traits. The number of five spiral bands is very stable as well as the white and smooth teleoconch. Some colour morphs of M. vermiculata look quite similar; however, so far all shells of the latter species could be differentiated by presence of the malleate teleoconch surface. This surface structure may be reduced to a small area above and around the aperture, but it is always clearly discernible. It differs from M. massylaea by its considerably smaller shell, the high globular spire, and the smooth teleoconch surface.