Plesiotrochus fallax ( Grateloup, 1832 )

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 : 330-331

Plesiotrochus fallax ( Grateloup, 1832)

(Fig. 3 E1, E2)

Cerithium fallax Grateloup, 1832 : nos 263, 265. — d’Orbigny 1852: nos 1478, 1480.

Hemicerithium fallax – Cossmann & Peyrot 1922: no. 579, figs 78- 83, 89.

Plesiotrochus fallax – Lozouet et al. 2001: 21, pl. 10, figs 1-3.

MATERIAL EXAMINED. — Sample F10: AMPG ( IV) 1602-1604 (three specimens); sample F11: AMPG ( IV) 1605, 1606 (two specimens).

DIMENSIONS. — Maximum height: 2.15 mm (incomplete).

DISTRIBUTION. — Early Miocene. NE Atlantic: France (Aquitaine Basin) ( Grateloup 1832; Cossmann & Peyrot 1922; Lozouet et al. 2001); Proto-Mediterranean Sea: Greece (this paper).

REMARKS

Until now, Plesiotrochus fallax had only been recordedin the Aquitanian of the Aquitaine Basin in France, where is somewhat variable (as shown by Lozouet et al. (2001)). The present specimens are mostly similar to figures 3a and 3b of Lozouet et al. (2001), since the spiral sculpture is inconspicuous, the shell is almost smooth, and the axial varices are relatively rounded. The aperture is broken in all available specimens.

The family Plesiotrochidae was transferred to the superfamily Campaniloidea by Healy (1993) based on recent species.

Modern representatives of the family feed on algae and live in coarse sediments, on reef slopes, sometimes between coral patches and sand with seagrasses ( Janssen et al. 2011)

Superfamily CERTITHIOIDEA J. Fleming, 1822 Family CERITHIIDAE Fleming, 1822

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.