Bellardithala obsoleta ( Brocchi, 1814 )

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 : 77-78

Bellardithala obsoleta ( Brocchi, 1814)

Plate 5 H 1 -H 2

* Voluta obsoleta Brocchi 1814: 646 , pl. 15, fig. 30.

Mitra striata Eichwald 1830: 221 .

Mitra obsoleta Brocch. — Bellardi 1850: 28, pl. 2, fig. 29.

Mitra obsoleta Brocchi —Fontannes 1880: 87, pl. 6, fig. 9.

Micromitra pusilla Bellardi 1888: 8 , pl. 6, fig. 48.

Micromitra obsoleta (Brocch.) — Bellardi 1888: 9, pl. 6, fig. 49.

Micromitra mangeliaeformis Bellardi 1888: 9 , pl. 6, fig. 50.

Thala obsoleta var. elatocostata Sacco 1904: 88 , pl. 19, fig. 24.

Thala obsoleta var. angustolonga Sacco 1904: 88 , pl. 19, fig. 25.

Pusia (Pusia) (Pusia) obsoleta ( Brocchi, 1814) —Rossi Ronchetti 1955: 243, fig. 129.

Voluta obsoleta Brocchi, 1814 — Pinna & Spezia 1978: 169, pl. 68, fig. 2.

Micromitra mangeliaeformis Bellardi, 1888 — Ferrero Mortara et al. 1981: 172, pl. 54, fig. 3.

Micromitra pusilla Bellardi, 1888 — Ferrero Mortara et al. 1981: 172, pl. 54, fig. 6.

Thala obsoleta ( Brocchi, 1814) — Giannuzzi-Savelli & Reina 1983: 233, text-fig. 2.

Thala obsoleta ( Brocchi, 1814) — Davoli 2000: 210, pl. 7, fig. 10, pl. 8, figs. 1, 2.

Thala obsoleta ( Brocchi, 1814) — Chirli 2002: 56, pl. 28, figs. 5-12.

Thala obsoleta ( Brocchi, 1814) — Landau et al. 2011: 29, pl. 15, fig. 6.

Thala obsoleta ( Brocchi, 1814) — Landau et al. 2013: 218, pl. 34, fig. 18-19.

non Mitra obsoleta Bronn [sic]—Hörnes 1852: 110, pl.10, fig. 32. [= Bellardithala kovaci Harzhauser & Landau, 2021 ).

non Thala obsoleta ( Brocchi, 1814) — Bałuk 1997: 39, pl. 11, fig. 2 [= Bellardithala kovaci Harzhauser & Landau, 2021 ).

Santa Maria material examined. Maximum height 5.9 mm, width 2.0 mm. DBUA-F 542-4 (1), Ponta dos Frades, Santa Maria Island, Azores, Touril Complex, Lower Pliocene.

Description. Shell medium-sized, moderately slender fusiform with cyrtoconoid spire and narrowly incised suture. Protoconch not preserved. Teleoconch of four weakly convex whorls, with periphery at abapical suture, rapidly increasing in height. First teleoconch whorl with rounded axial ribs, crossed by spiral threads (specimen too worn to count cords). Regularly spaced predominant axial ribs crossed by about six or seven spiral cords on penultimate whorl. Last whorl almost straight sided (incomplete, missing siphonal part), hardly constricted at base, bearing narrow cords and broader ribs, too worn to count, adapical subsutural spiral cord most prominent. Cords over fasciole prominent. Aperture moderately narrow with shallow anal sinus. Columellar callus indistinct, poorly delimited. Columella with three prominent folds (incomplete). Outer lip thickened, denticulate within. Siphonal canal missing.

Discussion. The genus Thala H. & A. Adams, 1853 has been used by authors for European Neogene species with a wide range of morphologies, none of which truly represents the genus Thala ( Harzhauser & Landau 2021) . Voluta obsoleta Brocchi, 1814 , was placed in a new genus Bellardithala Harzhauser & Landau, 2021 , characterised by medium-sized Thala - and Mitromica - like species with moderately slender fusiform shells, cancellate, weakly beaded or strongly reduced sculpture. Differing from Mitromica Berry, 1958 , in their episodic growth, indicated by the formation of denticles in juvenile specimens and from Thala in the predominant axial sculpture on early spire whorls. Occasionally with elongate denticles within outer lip.

The single Azorean specimen is incomplete and worn. Compared to specimens from the Mediterranean Pliocene the spiral cords are relatively fewer and stronger. However, there is some variability in the sculpture, and we provisionally consider them conspecific.

Distribution. Middle Miocene: Proto-Mediterranean Sea (Serravallian), Karaman Basin, Turkey ( Landau et al. 2013). Upper Miocene: Proto-Mediterranean Sea (Tortonian), Po Basin, Italy ( Bellardi 1888; Davoli 2000). Lower Pliocene: Atlantic, Santa Maria Island, Azores, Guadalquivir Basin, Spain ( Landau et al. 2011), northeastern Spain (NHMW coll.), Roussillon Basin, France (Fontannes 1880); central Mediterranean, Italy ( Bellardi 1888; Chirli 2002). Upper Pliocene: western Mediterranean, Estepona Basin, Spain (NHMW coll.).

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).