Cheilea equestris ( Linnaeus, 1758 )

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 : 38-39

Cheilea equestris ( Linnaeus, 1758)

Plate 2 F

* Patella equestris Linnaeus 1758: 780 .

Pileopsis Bredai Michelotti 1847: 137 , pl. 5, fig. 3.

Caliptraea [sic] Equestroides Millet 1854: 165 (nomen nudum).

Dyspotaea semicanalis Bronn in Hartung 1861: 120, fig. 4.

Dyspotaea semicanalis Bronn —Bronn in Reiss 1862: 33.

Mitrularia semicanalis Bronn — Mayer 1864: 54.

Caliptraea [sic] aequestroides Millet 1865: 598 .

Mitrularia bredai (Mich.) — Sacco 1896b: 46, pl. 5, figs. 29-30.

? Cheilea inexpectata (Boettger) — Zilch 1934: 247, pl. 13, fig. 62.

Cheilea equestris Linné — Abbott 1954: 165, pl. 21p.

Cheilea equestris Linné, 1758 — Brébion 1964: 306, pl. 7, fig. 23.

Cheilea inexpectata (Boettger, 1907) — Bałuk 1975: 173, pl. 3, fig. 6.

Mitrularia bredai ( Michelotti, 1847) — Ferrero Mortara et al. 1984: 253, pl. 43, fig. 6.

Cheilea bredai ( Michelotti, 1847) — Bertarelli & Inzani 1986: 178, figs. 1-5.

Cheilea equestris (Linneo, 1758) — Pantoli & Ruggieri 1988: 42, pl. 1, figs. 1-7, text-fig. 1.

Cheilea equestris (Linné, 1758) — Redfern 2001: 48, pl. 25, fig. 26.

Cheilea equestris ( Linnaeus, 1758) — Landau et al. 2004a: 81, pl. 20, figs. 1, 2.

Cheilea equestris ( Linnaeus, 1758) —Chirli 2008: 16, pl. 4, figs. 11-15.

Cheilea equestris ( Linnaeus, 1758) — Landau et al. 2018: 32, pl. 33, figs. 1-2.

Santa Maria material examined. Maximum diameter 30.0 mm. DBUA-F 1283-1 (1), DBUA-F 492 (1), Ponta do Castelo; DBUA-F 1071 (1), Pedra-que-pica, Santa Maria Island, Azores, Touril Complex, Lower Pliocene.

Description. Shell medium sized, fragile, ovate, capuliform, with a very depressed profile. Protoconch small, naticiform, multispiral of 2.5 whorls, partly immersed in the teleoconch, placed slightly posterior to midline and displaced slightly to the left. Junction with teleoconch sharply delimited by scar. Teleoconch consists of one rapidly expanding, weakly convex, flattened whorl. Sculpture of irregular, concentric ridges and rugae, and fine spiral threads. Aperture very large, circular, peristome complete, with irregular edge. Inner aspect bears horseshoe-shaped lamina extending from the inner side of the apex (obscured by matrix in Azorean specimens).

Discussion. The diagnostic horse-shoe shaped lamina typical for the genus Cheilea Modeer, 1793 is obscured in the Azorean specimens but the dorsal sculpture consisting of irregular, coarse concentric ridges and rugae are typical for C. equestris ( Linnaeus, 1758) . The dorsal sculpture changes with ontogeny so that juvenile specimens are elevated and almost smooth, whereas other shells are more depressed and strongly sculptured. The Azorean specimen is fully adult.

In Europe, C. equestris was present in Middle Miocene and Pliocene fully tropical assemblages but did not survive the cooling episode at the end of MPPMU1. Today, it has a tropical circumglobal distribution.

Distribution. Lower Miocene: Proto-Mediterranean, Italy ( Sacco 1896b). Middle Miocene:?Paratethys, Poland ( Bałuk 1975), Romania ( Zilch 1934). Upper Miocene: Atlantic (Tortonian), NW France ( Brébion 1964); Proto-Mediterranean, Italy ( Sacco 1896b). Lower Pliocene: Atlantic, Santa Maria Island, Azores (Bronn in Hartung 1861; Bronn in Reiss 1862; Mayer 1864); central Mediterranean, Italy ( Chirli 2006). Upper Pliocene: western Mediterranean, Estepona Basin ( Landau et al. 2004a); central Mediterranean, Italy ( Bertarelli & Inzani 1986). Upper Pleistocene: Red Sea, Hurghada, Egypt (NHMW coll.). Present-day: Circumglobal distribution; Indo-Pacific ( Wilson 1993), eastern Pacific ( Keen 1971); eastern Atlantic, Cabo Verde archipelago and West African shores (Rolán 2005; Ávila et al. 2015 b, 2022), southeastern Florida and West Indies ( Abbott 1954; Redfern 2013), western Atlantic, Bermuda, Carolinian biogeographic province.

Genus Hipponix Defrance, 1819

Type species. Patella cornucopiae , R̂ding, 1798 (Defrance 1819: 8), by subsequent designation ( Anton, 1838). Eocene , France .

Figures

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.