ammonites
Cleiothyridina ailakensis Reed 1925 (lamp shell)

Rhynchonellata - Athyridida - Athyrididae

Belongs to Cleiothyridina according to T. A. Grunt and V.Yu Dmitriev 1973

Sister taxa: Athyris (Cleiothyridina) bajtuganensis, Athyris (Cleiothyridina) epigona, Athyris (Cleiothyridina) warchensis, Cleiothyridina accola, Cleiothyridina acutomarginalis, Cleiothyridina anabathra, Cleiothyridina attenuata, Cleiothyridina bajkurica, Cleiothyridina baracoodensis, Cleiothyridina barbata, Cleiothyridina capillata, Cleiothyridina circularis, Cleiothyridina ciriacksi, Cleiothyridina corculum, Cleiothyridina dalmiriensis, Cleiothyridina davidsoni, Cleiothyridina deroissyi, Cleiothyridina dilimensis, Cleiothyridina echidniformis, Cleiothyridina excavata, Cleiothyridina globulina, Cleiothyridina grossula, Cleiothyridina hayasakai, Cleiothyridina interposita, Cleiothyridina intonsa, Cleiothyridina laminosa, Cleiothyridina laqueata, Cleiothyridina macleayana, Cleiothyridina maynci, Cleiothyridina mulsa, Cleiothyridina nana, Cleiothyridina nielseni, Cleiothyridina nikolaevi, Cleiothyridina orbicularis, Cleiothyridina ovalis, Cleiothyridina pectinifera, Cleiothyridina perthensis, Cleiothyridina pijaensis, Cleiothyridina pilularis, Cleiothyridina rara, Cleiothyridina rectimarginata, Cleiothyridina saraiensis, Cleiothyridina semiconcava, Cleiothyridina seriata, Cleiothyridina shenshuensis, Cleiothyridina simulans, Cleiothyridina solovjevae, Cleiothyridina subexpansa, Cleiothyridina tribulosa, Cleiothyridina tschironensis, Cleiothyridina uralica, Cleiothyridina xetriformis, Cleiothyridina zhexiensis, Cleiothyridellina accoliformis

Ecology: stationary low-level epifaunal suspension feeder

Average measurements (in mm): shell 20.4 x 22.5, valve 16.8 x 23.9