pygidium


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pygidium

[pī′jid·ē·əm]
(invertebrate zoology)
A caudal shield on the abdomen of some Arthropoda.
The terminal body segment of many invertebrates.
References in periodicals archive ?
The internal surface of the pygidium of the illaenid trilobite from the Nabala Regional Stage (middle Katian) is encrusted by multiple cornulitids (N = 15) and a single trepostome bryozoan colony with circular cross section (Fig.
a) Mid-posterior chaetigers, showing branched branchiae, b) distal end, dorsal view, c) distal end with pygidium in ventrolateral view.
Tiene poros perivulvares y el pygidium es amplio, subtendido por un angulo superior a 90[grados], con tres pares de lobulos redondeados y el borde (entre los segmentos VI y VII) con numerosos macroconductos ordenados en doble o triple hilera.
Pygidium covered by the elytra, not vertical, intermediate uroesternites not narrowed in the middle, head not or only slightly concealed within prothorax when viewed dorsally 2 1'.
The shell-boring polychaete species were identified on the basis of fifth setiger chaetae, prostomium and pygidium morphology, and branchiae distribution.
Pronotum, elytra, and pygidium with whitish pubescence; metepisternum, apical portion of metacoxa, and apical lateral abdominal sternites with white tufts of pubescence, forming a lateral whitish stripe.
Similar al macho (Figura 1B) y a las fotos de la serie tipo, un poco mas pequena, un adulto teneral, color rojizo oscuro, lustroso, cabeza muy corta, transversa, profundamente emarginada, dorsalmente pilosa y finamente puncturada; ojos redondos proporcionalmente mas pequenos, con el canthus proyectado anteriormente, espinoso; mandibulas cortas, sinuadas, dorsalmente carinadas, dos veces mas largas que la cabeza, angostas, proyectadas hacia arriba; palpos maxilares poco mas largos que las mandibulas; pronotum similar al del macho, pero poco proyectado, de aspecto rugoso, surco dorsal reducido, con la carina anterior de menor tamano; patas delanteras con las tibias mas delgadas y tarsos mas pequenos; elytra similarmente surcado, pero dejando ver el pygidium.
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.
5); (v) trochanter IV unmodified; (vi) basal segment of pygidium unnotched on either dorsal or ventral posterior borders; (vii) fixed process of the male copulatory apparatus with an anteroventral ledge.