Sampling locations of the investigated specimens. This map was produced with QGIS (2016, v2.18.12) using the Natural Earth data set.

Maximum Likelihood (RAxML) tree based on concatenated data set of COI, 16S, H3, and 5.8 S rRNA+ITS2. Numbers represent bootstrap support values from the ML analysis.

Bayesian Inference tree based on concatenated data set of COI, 16S, H3, and 5.8 S rRNA+ITS2. Numbers represent Bayesian posterior probabilities.

Alabastrina type specimens. A Helix soluta, syntype MHNL 45000679, Oran, Algeria, coll. Michaud, D = 24.15 mm B Helix alabastrites, syntype MHNL 45000690, Oran, Algeria, coll. Michaud, D = 22.48 mm. All photographs by Kneubühler & Neubert, × 1.5.

Alabastrina alabastrites (NMBE 549817), Kebdana Mountain, Morocco; A shell B situs C penis D penial lumen; D = 21.91 mm, H = 13.36 mm, situs length 27.57 mm (atrium-flagellum). All photographs by Kneubühler, shell × 1.5.

Alabastrina alabastrites (NMBE 549812), cave Ifri n’Ammar, Morocco; A shell B situs C penis D penial lumen; D = 19.72 mm, H = 13.00 mm, situs length 26.27 mm (atrium-BCD). BC lost during dissection. All photographs by Kneubühler, shell × 1.5.

Alabastrina alabastrites (NMBE 549813), hills El Batel, Morocco; A shell B situs C penis; D = 17.25 mm, H = 10.85 mm, situs length 13.46 mm (atrium-flagellum). Situs is not complete. All photographs by Kneubühler, shell × 1.5.

Alabastrina alabastrites (NMBE 549816), Etsedda/ Kebdana, Morocco; A shell B situs C penis; D = 22.77 mm, H = 13.45 mm, situs length 36.84 mm (atrium-BCD). BC destroyed. All photographs by Kneubühler, shell × 1.5.

Alabastrina tistutensis (NMBE 555174), Tiztoutine, Morocco; A shell B situs C penis; D = 19.59 mm, H = 8.74 mm, situs length 13.51 mm (atrium-flagellum). Situs not complete. All photographs by Kneubühler, shell × 1.5.

A Siretia pallaryi (NMBE 549815), Kebdana Mountain, Morocco, D = 16.82 mm, H = 8.81 mm; B S. pallaryi (SMF 75926), Teforalt (= Taforalt), Morocco, coll. CR Boettger, D = 19.38 mm. All photographs by Kneubühler & Neubert, × 1.5.

Otala lactea (NMBE 553246), W Almocageme, Portugal; A shell B situs C penis and atrium; D = 29.82 mm, H = 18.71 mm, situs length 41.34 mm (atrium-BCD). All photographs by Kneubühler, shell × 1.5.

Otala lactea (NMBE 554174), N Málaga, Spain; A shell B situs; D = 27.25 mm, H = 18.60 mm, situs length 22.90 mm (atrium-albumin gland); juvenile, BC destroyed. All photographs by Kneubühler, shell × 1.5.

Otala lactea (NMBE 555171), Hassi Ouenzga/ Oriental, Morocco; A shell B situs C penis and atrium; D = 22.63 mm, H = 14.85 mm, situs length 34.60 mm (atrium-flagellum). All photographs by Kneubühler, shell × 1.5.

Otala lactea (NMBE 549951), W Aoulouz, Morocco; A shell B situs; D = 27.01 mm, H = 15.77 mm, situs length 30.77 mm (atrium-flagellum); juvenile; situs not complete; BC destroyed. All photographs by Kneubühler, shell × 1.5.

Otala lactea (NMBE 554175), W Almería, Spain; A shell B situs C penis and atrium; D = 31.89 mm, H = 18.23 mm, situs length 57.86 mm (atrium-BCD). All photographs by Kneubühler, shell × 1.5.

Otala lactea (NMBE 545594); Etsedda/Kebdana, Morocco; A shell B situs C penis; D = 40.81 mm, H = 21.75 mm, situs length 61.47 mm (atrium-BCD), BC destroyed; D H. lucasii (syntype MNHN IM-2000-31721), Oran, Algeria, D = 35.4 mm. All photographs by Kneubühler & Neubert, shell original size.

Otala punctata (NMBE 534228); Makouda, Algeria; A shell B situs C penis; D = 36.02 mm, H = 22.37 mm, situs length 59.77 mm (atrium-BCD). All photographs by Kneubühler, shell original size

Otala punctata (NMBE 554171); W Málaga, Spain; A shell B situs C penis; D = 30.30 mm, H = 18.05 mm, situs length 70.10 mm (atrium-BC). All photographs by Kneubühler, shell × 1.5.

Otala xanthodon (NMBE 549825), Moulouya, Morocco; A shell B situs C atrium and penis; D = 23.13 mm, H = 14.49 mm, situs length 32.68 mm (atrium-BCD). BC destroyed. All photographs by Kneubühler, shell × 1.5.

Otala xanthodon (NMBE 549826), Moulouya, Morocco; A shell B situs C atrium and PP2 D penial chamber; D = 21.47 mm, H = 14.22 mm, situs length 37.23 mm (atrium-BCD). All photographs by Kneubühler, shell × 1.5.

Otala xanthodon (NMBE 549841), Kebdana Mountain, Morocco; A shell B situs; D = 26.85 mm, H = 15.74 mm, situs length 33.58 mm (atrium-flagellum). Situs not complete. All photographs by Kneubühler, shell × 1.5.

Otala xanthodon, Kebdana, Moulouya valley, Morocco; A shell from O. xanthodon (NMBE 555169), D = 22.33 mm, H = 13.61 mm; B shell from O. xanthodon (NMBE 555170), D = 23.10 mm, H = 13.37 mm. Kebdana, Djebel Sebaa Reyal/ Rif C shell from O. xanthodon (NMBE 549843), D = 27.77 mm, H = 16.04 mm. All photographs by Kneubühler, shell × 1.5.

Otala xanthodon (NMBE 549820), Guercif, Morocco; A shell B situs C atrium and penis; D = 26.74 mm, H = 15.96 mm, situs length 42.81 mm (atrium-BCD), BC destroyed; D Helix zaffarina Terver, 1839 (syntype MHNL 45001034), Oran, Algeria, coll. Michaud, D = 29.54 mm. All photographs by Kneubühler & Neubert, shell × 1.5.

Otala tingitana (NMBE 510549), Tarzout de Guigou, Morocco, D = 27.42 mm, H = 14.38 mm (specimens from the type locality of Archelix minettei Pallary, 1917). All photographs by Kneubühler, shell × 1.5.

“Tingitana minettei decussata” (NMBE 549840), Kebdana, Morocco; A shell B situs C atrium and penis; D = 32.45 mm, H = 16.12 mm, situs length 28.84 mm (atrium-flagellum). Situs not complete. All photographs by Kneubühler, shell × 1.5.