Finella perpusilla ( Grateloup, 1827 ) Thivaiou & Harzhauser & Koskeridou, 2019

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 : 335-336

Finella perpusilla ( Grateloup, 1827) n. comb. (Fig. 4 G1-G4)

Rissoa perpusilla Grateloup, 1827: 133 , no. 103.

Sandbergeria perpusilla – Landau et al. 2013: 48, pl. 54, figs 11-14 (cum. syn.).

MATERIAL EXAMINED. — Sample F11: AMPG ( IV) 2308-2383 (76 specimens); sample F12: AMPG ( IV) 2384-2399 (16 specimens) .

DIMENSIONS. — Maximum height: 2.10 mm.

DISTRIBUTION. — Early Miocene. NE Atlantic: France ( Cossmann & Peyrot 1922); Proto-Mediterranean Sea: Italy ( Sacco 1895b), Greece (this paper).

Middle Miocene. NE Atlantic: France ( Cossmann & Peyrot 1922; Glibert 1949); Proto-Mediterranean Sea: Turkey ( Landau et al. 2013); Paratethys: Austria ( Hörnes 1856), Poland ( Bałuk 1975), Hungary ( Strausz 1966), Romania ( Zilch 1934).

REMARKS

The species is placed here in the genus Finella (A. Adams, 1860b) since it bears more common characters with the type of this genus than with Sandbergeria Bosquet, 1861 (type species S. cancellata Nyst, 1836 , Early Oligocene of Belgium). These include a planktotrophic protoconch, a more conical shape, a short and indistinct siphonal canal, a straight columellar with broad callus, which forms a narrow columellar lip ( Marquet et al. 2008). Finella perpusilla has orthocline growth lines and fine ribs, as well as a very characteristic sculpture with regularly spaced inconspicuous spiral furrows (clearly visible in SEM pictures), absent on the middle part of the whorl. The shape of the shell can vary from more elongated with low whorl expansion, to less elongated and more conical with slightly wider whorls. The Greek specimens are very similar to the Serravallian specimens from Turkey ( Landau et al. 2013) concerning variabilty of morphology and sculpture.

The species was widespread in the Paratethys during the Miocene ( Zuschin et al. 2004, 2005, 2006) where it was an important component of the assemblages, but is absent from the NE Atlantic and North Sea Basin. Modern representatives of the genus are detritus feeders that live on mobile bottoms, sometimes associated with corals or seagrass (R. Janssen et al. 2011). Finella bruchae was also found within a seagrass-associated gastropod fauna in the Early Miocene of India ( Harzhauser 2014).

Figures

FIG. 4. — A1-A3, Bittium larrieyense Vignal, 1911: A1, AMPG(IV) 1891 (SEM image); A2, A3, AMPG(IV) 1646; B1-B3, Granulolabium plicatum (Bruguière, 1792): B1, AMPG(IV) 2089 (SEM image); B2, B3, AMPG(IV) 2167; C1-C3, Gibborissoia varicosa (de Basterot, 1825): C1, AMPG(IV) 2239 (SEM image); C2, C3, AMPG(IV) 2240; D, Mesohalina margaritacea (Brocchi, 1814), AMPG(IV) 2294 (SEM image); E1-E3, Terebralia lignitarum (Eichwald, 1830), AMPG(IV) 2304; F1-F3, Terebralia subcorrugata d’Orbigny, 1852, AMPG(IV) 2306; G1-G4, Finella perpusilla (Grateloup, 1827): G1, G2, AMPG(IV) 2308; G3, AMPG(IV) 2309 (SEM image); G4, AMPG(IV) 2309, protoconch (SEM image); H1-H4, Turritella turris de Basterot,1825:H1, H2, AMPG(IV) 2404;H3, AMPG(IV) 2405 (SEM image); H4, AMPG(IV) 2405, protoconch (SEM image). Scale bars: A1, C2, C3, G1, G2, H1-H3, 500 µm; A2, A3, D, 1 mm; B1, G3, C1, 400 µm; B2, B3, 5 mm; E1-E3, 10 mm; F1-F3, 2 mm; G4, H4, 200 µm.