Neritilia neritinoides ( Cossmann & Peyrot, 1917 )

Thivaiou, Danae, Harzhauser, Mathias & Koskeridou, Efterpi, 2019, Early Miocene Gastropods from the Felli Section (Proto-Mediterranean Sea NW Greece), Geodiversitas 41 (8), pp. 323-366 : 328

Neritilia neritinoides ( Cossmann & Peyrot, 1917) (Fig. 3 D1-D4)

Tinostoma (Megatyloma) neritinoides Cossmann & Peyrot, 1917: 14 , no. 126, pl. 7, figs 11-13.

Agapilia picta – Harzhauser & Kowalke 2001: 356, fig. 2/5-8 (non Férussac, 1823).

Neritilia neritinoides – Lozouet 2004: 450 , fig. 3.

MATERIAL EXAMINED. — Sample F2: AMPG ( IV) 1517-1533 (16 specimens); sample F3: AMPG ( IV) 1534-1540 (seven specimens); sample F7: AMPG ( IV) 1541-1542 (two specimens).

DIMENSIONS. — Maximum height: 1.21 mm (incomplete), maximum diameter: 1.23 mm.

DISTRIBUTION. — Oligocene. NE Atlantic: France ( Lozouet 2004). Early Miocene. NE Atlantic: France ( Cossmann & Peyrot 1917); Proto-Mediterranean Sea: Greece (this paper).

REMARKS

A complete description was provided by Lozouet (2004) in his review of the European Tertiary Neritiliidae , with remarks on this poorly known family of small gastropods. The most characteristic feature of the family is the structure of the protoconch, with a characteristic embryonic shell that has a different orientation to that of the rest of the protoconch; furthermore, it bears a semi-circular to circular scar and spiral ridges ( Kano et al. 2003; Lozouet 2004). In N. neritinoides the protoconch has regularly-spaced minute pits, observable in the Greek specimens despite their poorer preservation compared to the well-preserved French specimens. Almost all of the specimens have a hyaline shell and a broken outer lip; the protoconch measures about 270 µm; the largest specimen measures approximately 1.20 mm in height.

N. neritinoides seems to be the most common species of the family during the early Miocene, being found in France as well as Greece. In recent species, the planktotrophic larval phase occurs in saline environments before returning to estuaries for settling and migrating upstream as juveniles after metamorphosis ( Kano et al. 2003). This supports the dispersal of species through the saline-water barrier, thus explaining the dispersal of a single Miocene species throughout Europe.

Superfamily NERITOIDEA Rafinesque, 1815 Family NERITIDAE Rafinesque, 1815

Figures

FIG. 3. — A1-A4, Paroxystele orientale (Cossmann & Peyrot, 1917), AMPG(IV) 1506; B1-B3, Homalopoma acaste n. sp., holotype, AMPG(IV) 1512; C1, C2, Vitta picta (Férussac,1823),AMPG(IV) 1517; C3, AMPG(IV) 1543 (SEM image);C4, AMPG(IV) 1544 protoconch (SEM image); D1-D4, Neritilia neritinoides (Cossmann & Peyrot, 1917); D1, AMPG(IV) 1517; D2, AMPG(IV) 1541 (SEM image); D3, D4, AMPG(IV) 1541 protoconch close-ups; E1, E2, Plesiotrochus fallax (juv.) (Grateloup, 1832), AMPG(IV) 1605; F1-F3, Melanopsis sp., AMPG(IV) 2276. Scale bars: A, C1, C2, E2, 1 mm; B, 2 mm; C3, D3, 100 µm; C4, D1, E1, F, 500 µm; D2, 200 µm; D4, 50 µm.