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.
References in periodicals archive ?
6K), four internal moulds of pygidia NMW2012.45G.383, 392-394, five external moulds of pygidia NMW2012.45G.388-392.
A few pygidia of Asaphellus from the Psilocephalina lubrica Association differ from those of Asaphellus inflatus in having a more transverse outline of the pygidium, which is almost half as long as wide, more strongly impressed axial pygidial furrows and a more distinct pygidial border.
6O), 396-400, two external moulds of cranidia NMW2012.45G.401, 402, one attached cranidium and librigena NMW2012.45G.403, three librigenae NMW2012.45G.404-406, 15 internal moulds of pygidia NMW2012.45G.387 (Fig.
7E), 469-473, seven pygidia NMW2012.45G.164.1 (Fig.
Their overall morphology is similar to the cranidia illustrated here, but the poor quality of the material and illustration and the lack of illustrations of pygidia make the identification of our material uncertain.
Pygidia are necessary for reliable identification (e.g.
Five cranidia (NIGP152288, 152290-152293) and two pygidia (NIGP152287, 152289) from level BT5, Section 3.
179) noted that 'It is a common occurrence among dolichometopid trilobites to find almost identical cranidia associated with a great variety of pygidia ...'.
The described cephala, occurring stratigraphically close to the pygidia of morph A, are here considered to belong to a separate morph, but further studies may prove that they belong together.
Morph E (pygidia GIT 585-12-1, GIT 585-12-2, GIT 585-11-1, Figs 3E, 4A-E; cephala GIT 585-12-3, GIT 585-12-4, Figs 4E, 5D-F; hypostome GIT 585-12-5, Fig.
The pygidia have pleurae with anterior bands slightly narrower than posterior bands, pleural and interpleural furrows of nearly equal width and depth, which run nearly straight parallel to each other and reach rather close to the border, being not deeply incised.