Gastropods from the Burdwood Bank (southwestern Atlantic): an overview of species diversity Author Luca, Javier Di Author Zelaya, Diego G. text Zootaxa 2019 2019-01-10 4544 1 41 78 journal article 27685 10.11646/zootaxa.4544.1.2 2f89f82f-be57-45b4-ad3c-ed72a7647551 1175-5326 2618137 211842AA-6C98-425B-9377-1AF0DC78C893 Tectonatica impervia (Philippi, 1845) Fig. 3F Natica impervia Philippi, 1845a : 65 ; Philippi, 1845b : 42 , pl. 33, fig. 6; Melvill & Standen, 1912 : 122 Tectonatica impervia — Dell, 1990 : 163 , figs. 249, 274 (synonymy and radula); Pastorino, 2005b : 231 , figs. 36–45 (synonymy and radula) Examined material. 4 sh. (MACN-In 40671) Description. Shell height to 11.3 mm (up to 18.1 mm according to Dell 1990 ); ovate, solid. Protoconch of about 1 whorl; transition to teleoconch poorly defined. Teleoconch of up to 3.25 whorls, almost straight in outline; last whorl enlarged, very inflated, comprising about 95% of total shell height. Suture impressed. Surface whitish; only sculptured with faint growth lines. Aperture elongate-ovate, interior white; columellar callus strongly thickened, expanded, partially or fully covering the umbilicus.