pygidium


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pygidium

(pī-jĭd′ē-əm)
n. pl. pygid·ia (-ē-ə)
The posterior body region or segment of certain invertebrates.

py·gid′i·al (-ē-əl) adj.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.
References in periodicals archive ?
Pygidium transverse, semioval, slightly more than half as long as wide.
websteri showed variation in palp pigmentation pattern, the shape of the anterior edge of the prostomium, the shape of the major spines on chaetiger 5, and shape of the pygidium (Table III).
Abdomen flattened; 1st ventrite elongate; 2nd ventrite 0.7 times as long as 1st ventrite; 2nd--4th ventrites almost equal in length; 5th ventrite 1.3 times as long as 4th ventrite; pygidium not exposed.
A pygidium with two well-developed adhesive lobes and numerous cilia are located on the dorso-central part of the anus (Fig.
The pygidium was open and shaped like a suction cup, with a dorsal notch, and occasionally was dark in color.
Taxonomic features of cossurids are scarce, and refer principally to the number of asetigerous anterior segments, the origin of the branchial filament, the number of setigers in the anterior region, the structure of the pygidium, and types of setae.
Twig-nest parasitoids often have a smooth, undefined pygidium (Pitts and Manley, 2004; Pitts et al., 2004).
Also, a fragmentary pygidium attributed to the index species of the succeeding Megistaspis (Ekeraspis) armata Biozone (Balashova 1966, p.
4.7 mm long) and its pygidium is more highly polished with shagreening limited to its edges, instead of the entire surface.