Alvania mediolittoralis Gofas, 1989

Sacchetti, Claudia, Landau, Bernard & Ávila, Sérgio P., 2023, The Lower Pliocene marine gastropods of Santa Maria Island, Azores: Taxonomy and palaeobiogeographic implications, Zootaxa 5295 (1), pp. 1-150 : 47-48

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).

Figures

PLATE 1. A. Danilia pterostomus (Bronn, 1861), height 5.0 mm, width 4.0 mm, Forno da Cré (figure taken from Bronn in Hartung, 1861, pl. 19, fig. 2). B1-B2. Emarginula octaviana Coen, 1939, DBUA-F 487-1, height 1.8 mm, diameter 3.0 mm, Ponta do Castelo. C. Bolma cf. rugosa (Linné, 1767), DBUA-F 471-3, diameter 4.1 mm, Ponta do Castelo. D1-D5. Turbo hartungi Bronn 1861, DBUA-F 1295-1, height 9.0 mm, width 8.0 mm, Malbusca (east cave). E1-E3. Nerita cf. funata Dujardin, 1837, DBUA-F 917-1, height 4.0 mm, width 6.0 mm, Ponta do Castelo. F1-F2. Thericium crenulosum (Bronn, 1862), height 10.0 mm, width 6.0 mm, Ponta do Norte lighthouse, LNEG collection (unnumbered). G1-G2. Thericium hartungi (Mayer, 1862), height 29.0 mm, width 13.0 mm, Pinheiros (figure taken from Bronn in Reiss, 1862, pl. 1, fig. 11). H1-H2. Thericium incultum (Mayer, 1862), DBUA-F 1034-2, height 23.0 mm, width 10.0 mm, Macela viewpoint. I1-I2. Thericium incultum (Mayer, 1862), DBUA-F 1027-1, height 29.0 mm, width 11.0 mm, Malbusca II. J1-J2, K1-K2. Bittium miradouroense nov. sp., Holotype DBUAF 1034-5, height 6.8 mm, width 1.9 mm (J); Paratype DBUA-F 1034-6(1), height 5.3 mm, width 1.9 mm (K), Macela viewpoint. L1-L2, M1-M2. Bittium nov. sp., DBUA-F 488-2, height 4.5 mm, width 1.8 mm (L), height 4.2 mm, width 1.7 mm (M), Ponta do Castelo.

PLATE 2. A1-A2. Bittium nanum (Mayer, 1864), DBUA-F 1296-2, height 4.9 mm, width 2.0 mm, Malbusca. B. Tenagodus (Tenagodus) obtusus (Schumacher, 1817), DBUA-F 1283-2, height 12.0 mm, width 11.0 mm, Ponta do Castelo. C. Epitonium sp., DBUA-F 931-1, height 4.0 mm, width 2.8 mm, Pedra-que-pica. D1-D3. Janthina krejcii, SMF10135a, height 25.0 mm, diameter 32.0 mm, Macela viewpoint (pictures from Beu, 2017, fig. 26). E1-E3. Janthina typica (Bronn, 1861), DBUA-F-428, height 19.0 mm, diameter 21.0 mm, Ponta do Castelo, (pictures from Beu, 2017, fig. 25). F.Cheilea equestris (Linnaeus, 1758), DBUA-F 1283-1, diameter 30.0 mm, Ponta do Castelo. G1-G3. Hipponix sulcatus (Borson, 1820), DBUA-F 937-1, height 5.3 mm, diameter 14.0 mm, Ponta do Castelo. H1-H2. Euspira atlantica (Mayer, 1862), height 16.0 mm, diameter 19.0 mm, Ponta do Norte lighthouse, LNEG collection (unnumbered). I. Triphorid s.l., DBUA-F 471-5, height 3.2 mm, width 1.3 mm, Ponta do Castelo. J1-J2. Cerithiopsis cf. tubercularis (Montagu, 1803), DBUA-F 1023-1, height 3.0 mm, width 1.2 mm, Ponta do Castelo. K. Petaloconchus intortus (Lamarck, 1818), DBUA-F 946-2, height 13.0 mm, width 6.0 mm, Ponta dos Cedros. L. Thylacodes arenarius (Linnaeus, 1758), DBUA-F 869-1, height 33.0 mm, width 24.0 mm, Ponta dos Cedros. M1-M3. Alvania cancellata (da Costa, 1778), DBUA-F 1296-3, height 4.0 mm, width 2.2 mm, Malbusca.

PLATE 3. A. A1-A2. Alvania mediolittoralis Gofas, 1989, DBUA-F 962-2, height 2.1 mm, width 1.2 mm, Ponta do Castelo. B. Alvania sleursi (Amati, 1987), DBUA-F 471-4, height 2.0 mm, width 1.1 mm, Ponta do Castelo. C1-C2. Alvania sleursi (Amati, 1987), DBUA-F 962-3, height 3.2 mm, width 1.8 mm, Ponta do Castelo. D1-D3. Rissoina pusilla (Brocchi, 1814), DBUA-F 488-1, height 5.2 mm, width 2.1 mm, Ponta do Castelo. E1-E3. Macromphalina depressa (Boettger, 1907), DBUA-F 1023-3, height height 1.0 mm, width 1.8 mm, Ponta do Castelo. F. Calyptraea chinensis (Linnaeus, 1758), DBUA-F 926-1, diameter 18.0 mm, Malbusca 2. G1-G2. Schilderia utriculata (Lamarck, 1810), height 24.0 mm, width 15.0 mm, unknown locality, LNEG collection (unnumbered). H1-H3. Erato mayeri nov. sp., Holotype DBUA-F 1189-C, height 7.7 mm, width 5.3 mm, Pedra-que-pica. I1-I3. Erato mayeri nov. sp., Paratype DBUA-F 1291-1, height 8.9 mm, width 6.0 mm, Ponta dos Frades. J1-J4. Pseudopusula parcicosta (Bronn, 1862), DBUA-F 469-1, height 9.0 mm, width 6.5 mm, Ponta do Castelo.