Specimen MZ VIII Mg 4227/4 from the Callovian (Mid Jurassic) of Łuków (block in glacial drift) in lateral and apical view.

Diagnoza

Protoconch 2 conical, ornamented with two ribbon-like spiral keels. Shell conical with incised suture. Teleoconch ornamented with strong prosocline axial ribs (12–15 on the first whorl of teleoconch) and weaker spiral ribs (about six on the second whorl of teleoconch). Peristome with short anterior and weak posterior channels. Inner lip with or without a narrow callus.

Porównanie

This species is higly variable, both in number of axial ribs, and in their  strength. Maturifusus montagi Gründel, 1998 does not exceed the variability among the Astandes conspicuus from Łuków. Astandes ticurelatus (Gründel, 2001) is also very similar in shell morphology and differs only in the presence of rich pustulose ornamentation on the early part of the protoconch. Astandes kostromensis (Gerasimov,1955) differs significantly from A. conspicuus  in having more numerous and weaker spiral ribs. The species Astandes densatus Wade, 1917, Astandes densicostatus (Szabó, 1983), Astandes piccuus Beisel, 1983, and Astandes szaboi (Schröder,1995) with weaker axial ribs than A. conspicuus. Astandes keyserlingianus (Rouillier,1846) from Central Russia differs in having both spiral and axial ribs of the same dimension.

Autekologia

Występowanie geograficzne

Russia and Poland; in Poland found only in Łuków (block in glacial drift).

Zasięg czasowy

Callovian–Oxfordian (Mid to Late Jurassic); in Poland only Callovian.

Materiały muzealne

Material from Russia and over 100 shells from Łuków, Poland.

Literatura

Eichwald, E. 1868. Second section de la période moyenne. Lethaea Rossica ou paléontologie de la Russie 2, 641–1034.

Gründel, J. 1998a. Archaeo− und Caenogastropoda aus dem Dogger Deutschlands und Nordpolens. Stuttgarter Beiträge zur Naturkunde, Serie B (Geologie und Paläontologie) 260, 1–39.