Ascophrys Campillo et Deroux, 1974

Dovgal, Igor & Mayén-Estrada, Rosaura, 2015, A taxonomic revision of order Pilisuctorida (Ciliophora, Apostomatia) with keys to the subordinate taxa, Zootaxa 4040 (5), pp. 543-558 : 547

Genus Ascophrys Campillo et Deroux, 1974

The type species of the genus Ascophrys , A. rodor Campillo and Deroux, 1974 ( Fig. 2 E–F) was found on the cuticle of the shrimps Palaemon serratus (Pennant, 1777) (type host) and P. vari ans Leach, 1813 from Roscoff ( France, type locality). The detailed description of A. rodor life cycle ( Deroux et al. 1975) and ultrastructure ( Bradbury et al. 1987) were also denoted.

The complex life cycle which includes trophont, phoront and a tomite (swarmer) stages is characteristic for A. rodor ( Fig. 3 H–T). It is assumed that trophonts, at attachment site, feed of the exoskeleton chitin solubilized instead of exuvial fluid like the other representatives of Pilisuctorida. During the process of metamorphosis the tomite secretes the cyst and grows adopting an elongated shape characteristic for pilisuctorid trophont. The trophont stage transforms into phoront which in turn by nonlinear palintomy originates dozens of tomites. Each tomite is flat, devoid of cytostome, with a complex adhesive organelle on one side of the cell body and three short, parallel, oblique kineties on the other side. The swarmers are released through the rupture of cyst wall to infect new hosts, causing, as extremely pathogenic symbiont, damage for its shrimp host in case of mass infection.

Figures

FIGURE 2. Ciliates of genera Askoella and Ascophrys described by different authors. A—ventral side of Askoella janssoni; B—dorsal side of A. janssoni (scale bar 10 µm); C—macronucleus morphology of A. janssoni; D— A. heliostoma; E—trophont of Ascophrys rodor: F—phoront of Ascophrys rodor (A – C—modified from Fenchel, 1965; D—modified from Jankowski 1967 b; E-F—modified from Deroux, Campillo and Bradbury, 1975).

FIGURE 3. The life cycles of ciliates from genera Conidophrys and Ascophrys after different authors. A—trophont of Conidophrys with two tomites; B—emerged tomite of Conidophrys; C— Conidophrys’ tomite attached to seta; D—lacrymoid stage of Conidophrys’ trophont development; E—spheroid stage of Conidophrys; F, G—cucurbitoid stages of Conidophrys; H—frontal view of Ascophrys rodor zenithal tomite; I—frontal view of nadiral tomite (m—macronucleus; o. f. — adhesive organelle); J—phoront stage in circular cyst; K—the early stage of trophont development; L—trophont stage; M—the development of trophont to tomont (propagative trophont) stage; N—tomitogenesis; O—the hatching of tomites; P—the field of trophont primordial ciliature; Q—the primary anlage of infraciliature in young tomont; R—multiplication of infraciliature anlages before tomitogenesis (stage M); S and T—two sequential phases of tomite infraciliature morphogenesis (a— “ narrowed field; b— “ ampliate field). (A – G—modified from Chatton and Lwoff 1936; H – T—modified from Campillo and Deroux 1974).