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Mochtyella grazynae Mierzejewski, 1978
Diagnosis.- "Both right and left MI very wide and translucent. Main ridges of both jaws almost straight. Second ridge almost straight, distinctly denticulated, 0.35 total-jaw long. Basal ridge denticulated, 0.55-0.65 total jaw-ling. Laeobasal ridge unknown; as judged from the morphology of incomplete MIl, it is a mirror image of basal ridge." (Mierzejewski 1978, p. 277).
Occurence. Upper Silurian erratic boulders of Poland.
Remarks. Named in honour of Dr. Grazyna Mierzejewska (Bayer).
M. grazynae resembles most closely M. fragilis Szaniawski; the most important differences are in its almost straight main ridges of both MI, the position of the second ridge and more distinct denticulation, the more prominent denticulation of the basal ridge, and the wider outlines of both MI. Incomplete MI are easily recognizable, since an absence of basal and laeobasal ridges ridges results in very large false shanks.
Mierzejewski, P. 1978. New placognath Eunicida (Polychaeta) from the Ordovician and Silurian of Poland. - Acta Geologica Polonica 28, 2, 271-281.
Class Polychaeta, Ordo Eunicida, Family Mochtyellidae