Cancilla volvaria (Bronn, 1862)

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 : 78-79

Cancilla volvaria (Bronn, 1862)

Plate 5 I 1 -I 2 , J

* Mitra volvaria Bronn in Reiss 1862: 25, pl. 1, fig. 4.

Mitra volvaria Bronn — Mayer 1864: 82, pl. 7, fig. 62.

Type material. Single specimen height 15.5 mm, width 5.5 mm, Pinheiros, Santa Maria Island , Azores; whereabouts unknown ( Beu 2017:165) .

Santa Maria material examined. Maximum height 10.9 mm, width 4.8 mm. DBUA-F 937-2 (1), DBUA-F 470-1 (1), DBUA-F 1283 -E (1), Ponta do Castelo; DBUA-F 1291-2 (1), Ponta dos Frades; one specimen from LNEG collection (unnumbered), Ponta do Norte lighthouse, Santa Maria Island , Azores, Touril Complex , Lower Pliocene .

Original description. “ Eine ausgezeichnet Walzen-Spindel-f̂rmige ungerippte Art von 8'''-9''' Länge mit 5-6 am Gewinde kaum von einander abgesetzten Umgängen und 3-4 Spindel-Falten; die M̧ndung genau halb so lang als die ganze Schaale, deren Breite kaum ⅓ von der Länge beträgt. Die Schaale auf dem ganzen Gewinde spiral streifig; der letzte Umgang in der Mitte glatt, hinten mit 9-10, vorn wieder mit 2-3 Streifen versehen, welche alle deutlich ausgeprägt und etwas entfernt von einander sind. Die äussre Lippe scharf und einfach. Auf der inneren Seite ist vor den Spindel-Falten ein kurzes Nabel-Fältchen. Die M̧ndung fast durchaus gleichbreit. Diese Art ist bei ihrer geringen Gr̂sse vor andern sehr ausgezeichnet durch ihre Form, ihre lange M̧ndung und Art der Streifung [ A fine spindle-shaped, unribbed species of 8'''- 9''' (lines?) in length with a spire of 5-6 whorls hardly separated from each other and 3-4 columellar folds; the aperture is exactly half the height of the entire shell, the width is barely ¼ of the length. The spire whorls bear spiral cords; the last whorl bears 9-10 cords in the upper half, smooth mid-whorl, a further 2-3 cords below, which are all clearly delimited and somewhat distant from each other. The outer lip sharp and simple. On the ventral view there is a small umbilical chink in front of the columellar folds. The aperture is almost the same throughout. This species is very distinguished, due to its small size and its shape with a long aperture and the type of cords.]” (Bronn in Reiss 1862: 25).

Latin description. “ Testa cylindraceo-fusiformi; anfractibus 6, plano-convexis, sutus vix separatis; spira brevi, acuta, transversim striata ; ultimo anfractu maximo, ¾ testae efformante, superne et ad basim transversim striato; apertura elongata , dimidiam teste longitudinem vix superante, angusta; labro tenui, perpaulum arcuato; columella quadriplicata.” ( Mayer, 1864: 82).

Revised description. Shell small to medium sized, relatively solid, fusiform. Earliest spire whorls missing. Three slightly scalate whorls preserved, bearing four prominent spiral cords. Suture narrowly impressed, linear. Last whorl broadly rounded, weakly constricted at base, bearing flattened spiral cords, subobsolete mid-whorl. Aperture narrow, outer lip simple, anus sinus not developed, siphonal canal relatively short, notched at tip. Columella bearing four oblique folds shortening abapically.

Discussion. We have placed this species in the genus Cancilla Swainson, 1840 based on the presence of relatively strong spiral sculpture. Cancilla species are also characterised by weak cancellate sculpture on the earliest spire whorls ( Harzhauser & Landau, 2021: 7), but these are missing in the Santa Maria shell.

The specimen here illustrated ( Figs. 5 I 1 -I 2) does not fit exactly with the figure of the holotype ( Fig. 5 J ), which is slenderer and bullet-shaped. They do concur in the strong spiral sculpture and the presence of four strong folds on the columella. None of the fragments at hand agree with the holotype. Further material would be necessary to assess the number of mitrids present in the Santa Maria assemblages. Nevertheless, its presence is important as it is a marker of warm-water conditions.

Distribution. Lower Pliocene: Atlantic, Santa Maria Island, Azores (Bronn in Reiss 1862; Mayer 1864).

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 5. A1-A2. Tritia atlantica (Mayer, 1862), DBUA-F 1295-2, height 13.0 mm, width 6.5 mm, Malbusca (east cave). B1-B2 C1-C2. Tritia serraticosta (Ĥrnes, 1852), DBUA-F 1292-A, height 6.2 mm, width 4.1 mm (B); height 8.1 mm, width 4.2 mm (C), Macela viewpoint. D. Tritia vetulum (Mayer, 1862), height 12.0 mm, width 6.0 mm, Pinheiros (figure taken from Bronn in Reiss, 1862, pl. 1, fig. 5). E1-E2. Aplus sp., height 7.5 mm, width 4.0 mm, Ponta do Castelo, LNEG collection (unnumbered). F1- F2. Orania cf. bellardiana (Foresti, 1884), DBUA-F 828-2, height 17.0 mm, width 12.0 mm, Ponta dos Frades. G1-G2. Favartia suboblonga (d’Orbigny, 1852), DBUA-F 946-3, height 19.0 mm, width 10.0 mm, Ponta dos Cedros. H1-H2. Bellardithala obsoleta (Brocchi, 1814), DBUA-F 542-4, height 5.9 mm, width 2.0 mm, Ponta dos Frades. I1-I2 J. Cancilla volvaria (Bronn, 1862), DBUA-F 937-2, height 10.9 mm, width 4.8 mm (I), Ponta do Castelo; height 15.5 mm, width 5.5 mm (J), Pinheiros (figure taken from Bronn in Reiss, 1862, pl. 1, fig. 4). K. Mitra (s.l.) peregrinula Mayer, 1864 species inquirenda, height 5.5 mm, width 2.5 mm, Feteirinhas (= Ponta das Salinas) (figure taken from Mayer, 1864, pl. 7, fig. 61). L1-L2. Mitra (s.l.) sp., DBUA-F 1295-3, height 12.9 mm, width 7.0 mm, Malbusca (east cave). M. Africonus trochilus (Mayer, 1864), length 16.0 mm, width 9.0 mm (incomplete spire fragment), Pinheiros, (figure taken from Mayer, 1864, pl. 7, fig. 60). N1-N2. Lautoconus cf. anomalomamillus (Sacco, 1893), DBUA-F 924-1, height 22.0 mm, width 11.0 mm, Malbusca. O. Plagioconus sp., height 35.5 mm, width 16.0 mm, unknown locality, LNEG collection (unnumbered). P1-P2 Q. Stephanoconus candidatus (Mayer, 1862), DBUA-F 913, diameter 19.0 mm (apical fragment of juvenile), Ponta dos Frades (P); diameter 40.0 mm, height 22.0 mm (incomplete spire fragment), Pinheiros (figure taken from Bronn in Reiss, pl. 1, fig. 1).

FIGURE 5. A: Climatic zones and NE Atlantic Biogeographic Molluscan Provinces for the Pliocene (top left) and for the present times (top right) (adapted from Ávila et al. 2016b). Az: Azores Archipelago; Mad: Madeira Archipelago; Can: Canaries Archipelago; C Verde: Cabo Verde Archipelago. Note the location of the transition zones. B: Biogeographical classification of the Macaronesian archipelagos and NE Atlantic façade for the present times, according to Freitas et al. (2019). The Azores ecoregion, the Webbnesia ecoregion (which integrates the archipelagos of Madeira, Selvagens and Canary Islands), the South European Atlantic Shelf ecoregion and the Saharan Upwelling ecoregion, all belong to the Lusitanian Province. The West African Transition Province includes the Cabo Verde subprovince and the Sahelian Upwelling ecoregion.AST—Asturias (north Spain); AZO—Azores Archipelago; BIS—Bay of Biscay sensu lato, from English Channel to Punta Estaca de Bares, Galicia, Spain; CAB—Cabo Verde Archipelago; CAD—Gulf of Cádiz; BRI—British Isles; CAN—Canaries Archipelago; IBE— Iberian shores (from southern Bay of Biscay to Portugal and Gulf of Cádiz); MAD—Madeira Archipelago; MED—western Mediterranean Sea; NWA—northwest African shores (Atlantic Morocco, from Straits of Gibraltar south, Western Sahara to Cape Blanc, Mauritania); POR—Portugal [western Atlantic Iberian façade (from Cabo Vilán, western Galician shores, down to Cape S„o Vicente) and southern shores of Algarve]; SEL—Selvagens Islands; SEN—Senegal; STP—S„o Tomé and Príncipe Archipelago; TWAF—Tropical West Africa [from Cape Blanc (Mauritania) south to Cape Frio (Angola)].

FIGURE 1. Location map of the Azores Archipelago with information about the bathymetry and regional tectonic settings. NA—North American plate; EU—Eurasian plate; Nu—Nubian (African) plate; MAR—Mid‐Atlantic Ridge; TR—Terceira Rift; EAFZ—East Azores Fracture Zone; GF—Gloria Fault (adapted from Hyžný et al. 2021).