Philasterides cf. armatalis Song, 2000

Wilbert, Norbert & Song, Weibo, 2005, New contributions to the marine benthic ciliates from the Antarctic area, including description of seven new species (Protozoa, Ciliophora), Journal of Natural History 39 (13), pp. 935-973 : 946-947

Philasterides cf. armatalis Song, 2000

( Figure 1C )

Only a few cells found in two protargol-impregnated slides, so that it can be described only at infraciliature level. According to the oral structure and general somatic infraciliature, it seems to be an undescribed member of the genus Philasterides . However, it has to be treated as an unknown species until further information is obtained.

Description

Cells about 40620 M m long after protargol impregnation; body shape long oval to slender, circular in cross-section; apical end widely pointed with small apical plate surrounded by somatic kineties ( Figure 1C , arrowhead); posterior end generally rounded. Ventral surface slightly indented around buccal area, dorsally convex. Buccal field about 50% of cell length. One large oval macronucleus centrally located, 12616 M m in size; position of micronucleus uncertain, possibly adjacent to macronucleus.

About 22 somatic kineties longitudinally arranged, extending over entire length of body and mainly composed of dikinetids throughout. Each row with about 28 (paired or single) basal bodies.

Buccal apparatus consisting of three well-developed membranelles (M1–3) and one short paroral membrane which extends anteriorly to about the middle of membranelle 2. Membranelle 1 (M1) long and consisting of about 11 transverse rows of kinetosomes; membranelle 2 (M2) about half as long as M1 with ca five rows; membranelle 3 (M3) smaller, close to M2 with only three transverse rows. Paroral membrane likely not bipartite (? impossible to detect since cells lying on side). Scutica (Sc) with several pairs of basal bodies, sparsely arranged, posterior to cytostome ( Figure 1C , double-arrowheads).

Remarks

This organism differs from the marine form P. armatalis Song, 2000 in structure of scutica, buccal apparatus, smaller body size and lower in having fewer ciliary rows (see Song 2000).

Figures

Figure 1. (A) Amphileptus sp., (B) Pleuronema coronatum and (C) Philasterides cf. armatalis after protargol impregnation. (A) Right side view of infraciliature, arrows mark the suture formed by some shortened kineties, arrowheads indicate the extrusomes; (B) ventral-left view, to show the general appearance of infraciliature and nuclear apparatus (arrows mark the micronuclei); (C) left side view, arrowhead marks the apical plate; arrow indicates the anterior end of paroral membrane, double-arrowheads mark the scutica. Ma, macronucleus; M13, membranelle 1, 3. Scale bars: 70 Mm (A); 30 Mm (B); 15 Mm (C).