Triphora (s.l.) sp., 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 : 337

Triphora (s.l.) sp.

( Fig. 5 B1, B2)

MATERIAL EXAMINED. — Sample F10: AMPG ( IV) 2437, 2438 (two specimens); sample F11: 2439-2442 (four specimens).

DIMENSIONS. — Maximum height: 2.10 mm (incomplete).

DISTRIBUTION. — Early Miocene. Proto-Mediterranean Sea: Greece (this paper).

DESCRIPTION

Shell minute, turriculate. Protoconch conical of 4.5 whorls. Protoconch II bears two spiral keels and regularly-spaced axial riblets. Four teleoconch whorls preserved. First whorl bears two beaded cords; cord 1 placed below suture; cord 2 above abapical suture. Axial sculpture of smooth, slightly prosocline ribs, weaker than cords, with beads forming at instersections.

REMARKS

All of the specimens recovered are incomplete. Therefore, the complete sculpture and structure of the teleoconch are not available. There are some similarities with the species recovered in the Serravallian of Turkey ( Landau et al. 2013), Triphora (s.l.) sp., for which the third beaded cord appears on the sixth teleoconch whorl.

A slight concavity of the early teleoconch is reminiscent of Obesula sp. (Van Dingenen et al. 2016), but no more characters of the present shell can place it in this genus. The present species also has a similar early teleoconch sculpture to Marshallora adversa (Montagu, 1803) ( Marquet 1996) , but with a different protoconch structure and with the aperture missing from our specimen, it is impossible to attribute the species to Marshallora ( Bouchet, 1985) .

Figures

FIG. 5. — A1, A2, Nodiscala cf. rugatina de Boury in Cossmann, 1912: A1, A2, AMPG(IV) 2335; B1, B2, Triphora (s.l.) sp.: B1, AMPG(IV) 2439 (SEM image); B2, AMPG(IV) 2439, protoconch (SEM image); C1-C4, Metaxia sp.: C1, AMPG(IV) 2443, protoconch (SEM image); C2, AMPG(IV) 2443 (SEM image); C3, C4, AMPG(IV) 2443; D1-D3, Dizoniopsis sp.: D1, D2, AMPG(IV) 2445; D3, AMPG(IV) 2446 (SEM image); E1, E2, Rissoina subconoidea (Grateloup, 1847); E1, E2, AMPG(IV) 2448; F1, F2, Zebinella sp., AMPG(IV) 2451; G1-G4, Alvania amphitrite n. sp.: G1, G2, holotype, AMPG(IV) 1503; G3, paratype 2, AMPG(IV) 1505 (SEM image); G4, paratype 2, AMPG(IV) 1505, protoconch (SEM image); H1-H4, Alvania transiens (Sacco, 1895): H1, H2, AMPG(IV) 2455; H3, AMPG(IV) 2456 (SEM image); H4, AMPG(IV) 2456, protoconch (SEM image); I1, I2, Xenophora sp., AMPG(IV) 2461. Scale bars: A,D1-D3, F1, F2, G1, G2, H1-H3, 1 mm; B1, C2-C4,E1, E2, G3,500 µm; B2, H4, 400 µm; C1, G4, 200 µm; I1, I2, 2 mm.