Ampletochilina 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

Genus Ampletochilina Schallreuter, 1969

Type species: Ampletochilina trapezoidea Schallreuter, 1969 , Öjlemyrflint erratic boulder (upper Ordovician), Isle of Gotland ( Baltic Sea ) .

Species included:? Platybolbina ? granifera ( Sarv, 1962) Schallreuter, 1969.

Diagnosis.—Medium−sized. Outline amplete. Cardinal angles distinctly>90 °. Tubulate velar frill restricted, from anterocentral to posteroventral region, short posterior terminal spine. Weakly convex dolon, open at both ends, i.e., no distinct terminations. Marginal sculpture as ridge, dimorphic: broader in females at the antrum. Antrum bordered on both sides by faint ridge−like antral fences. Surface smooth, punctate.

Remarks.— Ampletochilina ryghooftensis Schallreuter, 1987 is assigned here to the genus Levisulculus , mainly because of the slightly preplete outline, the dolon being anteriorly more strongly convex than ventrally (but not as strong as in other species of the genus), and the antrum terminating posteriorly already in the centroventral region without abrupt termination ( Schallreuter 1967: text−fig. 2.1).

Comparisons.— Ampletochilina differs from Levisulculus and Swantina by its amplete outline, larger cardinal angles, and the long antrum, which gradually terminates at both ends.

Stratigraphic and geographic range.—Late Upper Ordovician (Vormsi−Pirgu,?Porkuni), Baltic region.