Ampletochilina trapezoidea Schallreuter, 1969

Schallreuter, Roger E. L. & Hinz-Schallreuter, Ingelore C. U., 2010, Sexual dimorphism and pore systems in Ordovician ostracodes, Acta Palaeontologica Polonica 55 (4), pp. 741-760 : 758-759

Ampletochilina trapezoidea Schallreuter, 1969

Figs. 5A–D, 7A.

1969 Ampletochilina trapezoidea gen. et sp. nov.; Schallreuter 1969: 347–348, fig. 2.

1984 Ampletochilina trapezoidea Schallreuter ; Sarv and Meidla 1984: 12, table 2 (p. 9), 4 (p. 19).

1986 Ampletochilina trapezoidea Schallreuter, 1969 ; Schallreuter 1986: 16 (1987: 216), pl. 1: 7; 17 (1987: 217).

?1987 Ampletochilina cf. trapezoidea Schallreuter, 1969 ; Schallreuter 1987b: 19.

1990 Ampletochilina trapezoidea Schallreuter, 1969 ; Abushik in Abushik et al. 1990: 57, 232, pl. 6: 5 (= Schallreuter 1969: fig. 2.1) non 1992 Ampletochilina aff. trapezoidea Schallreuter, 1969 ; Sidaravičienė 1992: 142, 243, fig. 3 (faunal log), table 2 (p. 214), pl. 36: 2.

?1993 Ampletochilina cf. trapezoidea Schallreuter, 1985 ; Schallreuter 1993: 46, 242, 243, pl. 47B: 1.

1996 Ampletochilina trapezoidea Schallreuter, 1969 ; Meidla 1996: 29, 30, table 9 (p. 203), figs. 24, 29 (cf.), 31–32, 34 (logs), pl. 3: 7.

?1996 Ampletochilina aff. trapezoidea Schallreuter, 1969 ; Sidaravičienė 1996: fig. 3 (log); table 11 (p. 36).

Holotype: Right female valve GG−25−10. Catalogue of Herrig and Nestler 1989 no. 38, catalogue of Keyser and Schöning 1996 no. 97 (Fig. 5D; Schallreuter 1969: text−fig. 2.1–2; Abushik in Abushik et al. 1990: pl. 6: 5 [= Schallreuter 1969: fig. 2.1]).

Type locality: Beach of Visby , Isle of Gotland .

Type horizon: Erratic boulder 794 (Inv. XII 1302).

Diagnosis.—Females mostly between 1.30 and 1.70 mm long. Outline trapezoidal, amplete. Dorsal angles both distinctly exceeding 90 °. Domicilium weakly convex. Muscle spot indistinct. Tecnomorphic velar frill rather broad, terminating spine−like posteriorly. Velar dolon open at both ends, terminating in the posteroventral region. Lateral surface with pores, otherwise smooth.

Comparison.— Ampletochilina ? granifera ( Sarv, 1962) differs from A. trapezoidea in being slightly larger (1.78 mm), and strongly pustulate (Fig. 4H; Sarv 1962: pl. 1: 4–7).

Stratigraphic and geographic range.— Estonia: Vormsi−Pirgu ( Meidla 1996), Lithuania:?Vormsi ( Sidaravičienė 1992). Öjlemyr flint boulder of the Isle of Gotland (Baltic Sea) and the Isle of Sylt (North Sea).