Testacella (Testacella) riedeli Giusti, Manganelli & Schembri, 1995

Figs 40–45, 82

Testacella riedeli – Giusti et al. 1995: 317 –326, figs 288–293, 302 – Col de Kefrida, Bejaia, Algeria.

Material examined.

• 2 exx; Algiers, Dely Ibrahim; 36°45.233'N, 2°59.117'E; 260 m a. s. l.; October 2018; R. Radmini leg. (Figs 40, 41). • 3 exx; Tizi-Ouzou, Makouda, Tigoulmamine; 36°48.167'N, 4°1.867'E; 350 m a. s. l.; November 2019; R. Radmini leg. • 5 exx; Tizi-Ouzou, Yakouren, Yakouren Forest; 36°44.750'N, 4°26.100'E; 720 m a. s. l.; November 2019; R. Radmini leg. • 3 exx; Tizi-Ouzou, Mizrana, Mizrana Forest; 36°50.050'N, 4°4.533'E; 730 m a. s. l.; November 2019; R. Radmini leg. • 2 exx; Jijel, National Park of Taza, Garouche forest; 36°40.033'N, 5°38.367'E; 700 m a. s. l.; January 2021; G. Sadouk leg. • 1 ex; Jijel, National Park of Taza, Tabola; 36°42.567'N, 5°33.000'E; 54 m a. s. l.; January 2021; G. Sadouk leg.

Diagnosis.

Vas deferens long, distally widened and with irregularly spaced muscles; penis enveloped by a thick muscular and glandular sheath, from which penial retractor muscle emerges (Figs 42, 43); proximal penis long and slender; distal penis half length of proximal penis, progressively widening before entering genital atrium (Fig. 44); short wide vagina; initially flared duct of the bursa copulatrix, ending in large oval bursa copulatrix; internal walls of the distal penis and vagina with several longitudinal flaps (Fig. 45).

Distribution.

Northern Algeria, where it is widespread and quite common, and Gozo Island (Maltese Islands) (Giusti et al. 1995).

Ecology.

Testacellids are subterranean and emerge only on wet days. They feed primarily on earthworms.

Remarks.

The populations examined enable us to expand the range of this species to the west, up to the Algiers province (Fig. 1 B). Additionally, we provide the first morphological data on the internal structure of the penis and vagina (Fig. 45).

Key for the identification of the Algerian slugs and semi-slugs, referring to fully grown, living specimens