Oxychilus draparnaudi

Oxychilus draparnaudi (H. Beck, 1837) Fig. 4 Worldwide distribution. Originally described from France, probably in the Montpellier area (Giusti and Manganelli 1997). Its native range includes western Europe and the western Mediterranean region (Barker 1999). It has spread to other parts of the world, including North America (Forsyth 2004) Russia, North and South Africa, Asia, Australia, and New Zealand (Barker 1999), Madeira (Seddon 2008), and Argentina (Virgillito and Miquel 2013). Distribution in Mexico. Querétaro (Cadereyta de Montes), Tlaxcala (Atlihuetzia), State of Mexico (Tlalnepantla), CDMX (Álvaro Obregón, Benito Juárez, Tlalpan). According to Morrone (2019), localities belong to the Sierra Madre Oriental and Transmexican Volcanic Belt Province. Diagnostic features. 15 specimens were dissected. Anatomically, all of them displayed the genital features typical of O. draparnaudi as described by Giusti and Manganelli (1997): a penis with a very slender proximal portion and a wider distal portion, both separated by a “ bottle-neck ” (= BS, i. e., a twisted duct or constriction) covered by a thin translucent sheath (Fig. 4 D, G). Internally the proximal penis shows prominent papillae (Fig. 4 F, I), while the distal penis shows four to five thin longitudinal internal folds (Fig. 4 E, H). Shell discoidal (Fig. 4 B, C) with a depressed spire (Burch 1962), thin, yellowish, shiny; shell surface generally smooth with fine growth lines most evident near the suture and few very fine spiral lines (Fig. 4 A). Shell whorls: 5 ½ to 6. Umbilicus moderately wide, 1 ⁄ 6 of maximum shell diameter. Shell diameter 9–13 mm, shell height 3–6 mm (Fig. 7). Aperture width: 3.00– 4.95 mm. Radula (n = 5) composed of 30 rows with ~ 25 teeth / row (Fig. 8 A). Radular formula: C / 3 + 2–3 L / 3 + 0–1 LM / 2 + 9–12 M / 1.