The Lower Pliocene marine gastropods of Santa Maria Island, Azores: Taxonomy and palaeobiogeographic implications Author Sacchetti, Claudia 0000-0002-3225-3139 claudiasacc@icloud.com Author Landau, Bernard 0000-0002-7768-8494 bernardmlandau@gmail.com Author Ávila, Sérgio P. 0000-0002-3225-3139 claudiasacc@icloud.com text Zootaxa 2023 2023-05-24 5295 1 1 150 http://dx.doi.org/10.11646/zootaxa.5295.1.1 journal article 53396 10.11646/zootaxa.5295.1.1 82286fdc-a858-447c-9980-da2e8985d19c 1175-5326 7965273 F3A52660-70B8-439F-A7A0-F45ADC975EA5 Alvania mediolittoralis Gofas, 1989 Plate 3 A 1 -A 2 * Alvania mediolittoralis Gofas 1989: 39 , figs. 1-4, 15. Alvania mediolittoralis Gofas, 1989 — Ávila et al . 2002: 353 , figs. 45-48, 52. Alvania mediolittoralis Gofas, 1989 — Ávila et al . 2005: 61 , fig. 5A. Alvania mediolittoralis Gofas, 1989 —Ávila 2005: 57, plate 5, figs. 1-14. Alvania mediolittoralis Gofas, 1989 — Ávila et al . 2008c , p. 31 -40. Alvania mediolittoralis Gofas, 1989 — Martins et al . 2009: 62 , pl. 9, fig. 138. Alvania mediolittoralis Gofas, 1989 — Ávila et al . 2009a: 23 , 29. Alvania mediolittoralis Gofas, 1989 — Ávila et al . 2010: 28 , fig. 27 (4-7). Alvania mediolittoralis Gofas, 1989 —Ávila 2013: 110, figs. 5C-F. Santa Maria Material examined. Maximum height 2.1 mm, width 1.2 mm. DBUA-F 962-2 (1), Ponta do Castelo, Santa Maria, Azores . Description. Shell medium sized for genus, rissoiform, imperforate, with conical spire. Protoconch and early teleoconch whorls not preserved. Penultimate whorl almost flat sided, with periphery at abapical cord placed just above suture. Suture deeply impressed. Sculpture on penultimate whorl of 16 narrow, slightly prosocline ribs, overrun by four subequal spiral cords. Small, rounded tubercles developed at sculptural intersection. Last whorl evenly ovate, with five tubercles cords above the level of the aperture and four non-tubercular cords over the base. Aperture ovate-pyriform, outer lip thickened by varix, with beveled edge, six weak denticles within, anal sinus weakly developed. Columella oblique, peristome complete. Discussion. Alvania mediolittoralis Gofas, 1989 is an extant endemic species from the Azores and Madeira with a paucispiral protoconch. The Azorean specimen at hand is missing the apex and half of the first teleoconch whorl. However, the conical spire profile, the whorls separated by deep canaliculate suture, and the character of the sculpture with five tubercular cords above the aperture and three or four smooth cords over the base, are consistent with the species. Distribution. Lower Pliocene: Atlantic, Santa Maria Island, Azores (this paper). Present-day: Atlantic, Azores ( Gofas 1989 ; Hoenselaar & Goud 1998 ; Ávila 2000; Ávila et al . 2005 ; Martins et al. 2009 ; Ávila et al . 2009b ), Madeira ( Hoenselaar & Goud 1998 ).