Successive reduction of the last instar larva of Loricifera, as evidenced by two new species of Pliciloricus from the Great Meteor Seamount (Atlantic Ocean)

The adult of P. senicirrus sp. n. is characterized, e.g., by clavoscalids with many fine transversal striae, claw-like type B spinoscalids of the fourth row ventrally winged and with seven embedded needle-like teeth, edge of the lorica with 24 small protrusions, and 20 papillate flosculi at caudal end. The Higgins-larva of P. senicirrus sp. n. is characterized, e.g., by the wide and frill-like first section of the mouth cone, the second segment of spinoscalids with ventral serration and double tip, long anterosetae with strong spinules, and by the toes being nearly as long as the short lorica, to name a few. The most obvious feature is the extreme length of the three pairs of posterosetae. The posteroterminal setae are nearly as long as the whole body. The seventh instar Higgins-larva of P. senicirrus sp. n. is not reduced as in the case of P. corvus sp. n.