Circoniscus Pearse, 1917

Campos-Filho, Ivanklin Soares, Sfenthourakis, Spyros, Gallo, Jéssica Scaglione, Gallão, Jonas Eduardo, Torres, Dayana Ferreira, Chagas-Jr, Amazonas, Horta, Lília, Carpio-Díaz, Yesenia Margarita, López-Orozco, Carlos Mario, Borja-Arrieta, Ricardo, Araujo, Paula Beatriz, Taiti, Stefano & Bichuette, Maria Elina, 2023, Shedding light into Brazilian subterranean isopods (Isopoda, Oniscidea): expanding distribution data and describing new taxa, Zoosystema 45 (19), pp. 531-599 : 552-553

Genus Circoniscus Pearse, 1917

Circoniscus Pearse, 1917: 4 .

TYPE SPECIES. — Circoniscus gaigei Pearse, 1917 , by monotypy (see Schmidt & Leistikow 2004).

DIAGNOSIS. — After Schmidt (2007): animals with endoantennal conglobation; roller habitus (sensu Schmalfuss 1984); dorsal surface smooth bearing small scale-setae; pereonites 1-7 with one line of short noduli laterales inserted at same line and near posterior margins; cephalon with wide frontal shield, sometimes projecting backwards over vertex, eyes composed of many ommatidia (absent in troglobionts); pereonite 1 epimera with posterior schisma, pereonite 2 and 3 epimera with ventral lobe or simple; pleon outline continuous with that of pereonite 7; telson triangular with broad rounded apex not covering uropod endopods; antennula of three articles; antennal flagellum of two subequal articles (sometimes distal article slightly longer), apical organ subequal or longer than distal article of flagellum; mandibles with molar penicil dichotomized, left mandible with 2+1 penicils, righ mandible with 1+1 penicils; maxillula outer endite with 4+5-6 teeth, outer set bearing four or five teeth apically cleft, accessory tooth and slender seta between outer and inner sets; maxilla bilobate; maxilliped endite bearing one penicil; pereopods 1-7 merus and carpus bearing scales on sternal margins (sometimes wide and dense); pereiopod 1 carpus with transverse antenna-grooming brush (sometimes wide); pereopod 7 basis with vestigial water-conducting scale-rows, ischium and/or merus sometimes sexually dimorphic; dactylar seta simple or hirsute, ungual seta simple; uropod protopod subrectangular and flattened; pleopod 1 and 2 exopods with respiratory areas; male pleopod 1 endopod tip bent outwards; male pleopod 5 exopod triangular with distal portion elongated.