Mangelia (s.l.) sp., Risso, 1826

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 : 344

Mangelia (s.l.) sp.

(Fig. 6 D1-D4)

MATERIAL EXAMINED. — Sample F11: AMPG ( IV) 2474-2477 (four incomplete specimens).

DIMENSIONS. — Maximum height: 3.66 mm (incomplete); maximum width: 1.55 mm.

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

DESCRIPTION

Protoconch multispiral, dome shaped, eroded, consists of 3 whorls, maximum diameter is 400 µm. Teleoconch of 3.5 whorls; axial sculpture composed of opisthocline regularly-spaced rounded ribs, about 12 on each whorl; fine axial regularly spaced growth lines. Spiral sculpture has four main equidistant cords; the second cord is more prominent and forms an angle of the spire from the second teleoconch whorl on. Spaces between cords occupied by secondary finer cords, two between each main spiral cord. Microsculpture consists of finer and irregularly spaced spiral cords. Intersections of growth lines and cords forms beads.Suture smooth; aperture missing; observed inner lip smooth.

REMARKS

The preservation state of the specimens does not allow a certain generic assignment.In one specimen of the studied material, part of the protoconch II sculpture is preserved; it consists of eroded axial riblets.The overall shape and sculpture that consists of finely beaded cords, is typical of members of the family.

A morphologically similar species from the Middle Miocene (Serravallian) of Turkey is Mangelia sp. ( Landau et al. 2013), with a similar spiral sculpture, yet less angular whorls than the present species.

A similar species from the Miocene of the North Sea Basin is Sorgenfreispira plicatelloides (Nordsieck, 1979) (A.W. Janssen 1984; Moths et al. 2010); it has a similar protoconch in shape and shouldered teleoconch whorls. Sorgenfreispira sorgenfreii (Nordsieck, 1979) is another species from the Miocene of the Netherlands that has some similarities (protoconch shape and teleoconch sculpture) but with less axial ribs and more rounded whorls. In the stratotype area of the Aquitanian (Aquitaine, France), there are no recorded species of Sorgenfreispira, but other Mangeliidae are present.Namely Bela elegantissima (Peyrot, 1931) which resembles the present species in having a similar teleoconch sculpture and shouldered whorls, but is much larger in size (maximum height about 8 mm) and has six teleoconch whorls.

Figures

FIG. 6. — A1-A3, Costoanachis cf. terebralis (Grateloup, 1834), AMPG(IV) 2467; B1, B2, Pusia cf. pyramidella (Brocchi, 1814), AMPG(IV) 2469; C1-C4, Athleta rarispina (Lamarck, 1811), AMPG(IV) 2462; D1-D4, Mangelia (s.l.) sp.: D1, D2, AMPG(IV) 2474; D3, D4, AMPG(IV) 2475, detail of microsculpture (SEM images). Scale bars: A1, A2, B1, B2, D1, D2, 1 mm; C1-C4, 10 mm; D3, 300 μm; D4, 100 μm.