Amphileptus, Ehrenberg, 1830

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 : 937-938

Amphileptus sp.

( Figures 1A , 12A )

We identified this organism from a protargol-impregnated slide (n 54). Since no living observation was able to be carried out, that is, the morphology in vivo and the position/

number of the contractile vacuoles as well as other diagnostic characters remain unclear, this organism has to be hence treated as an unknown form here.

Description

Cells after protargol impregnation generally form-constant ( Figure 1A ), ca 200 M m in length, which seems not to have evident (?) tail. Two ellipsoid macronuclear nodules, large and in mid-body position, arranged closely together. No micronucleus detected. Extrusomes (in protargol-impregnated specimens) rod-shaped, slightly curved, about 8–10 M m long; densely distributed in oral region and scattered in other parts of body ( Figures 1A , 15A ).

Infraciliature typical of genus. On right side, ca 50 densely ciliated somatic kineties forming a conspicuous suture in mid-body (arrows in Figure 1A ) whereas on left side probably over 12 (? not clearly detected) loosely ciliated kineties (including perioral kinety), all of which seem to extend along whole length of cell. Dorsal brosse composed of ‘‘numerous’’ basal body pairs and extending posteriorly to about half of cell length.

Remarks

Most studies using modern methods on this genus have been carried out on freshwater forms (Fryd-Versavel et al. 1975; Foissner 1984, 1986; Dragesco and Dragesco-Kernéis 1986; Song and Wilbert 1989. Considering the cell size, general appearance after impregnation and the habitat, the present organism is similar to the large marine form, Amphileptus marinus ( Kahl 1931) which was recently redescribed by Song et al. (2003). The latter has, however, conspicuously lower number of right somatic kineties (ca 50 versus 20–27). It possibly represents an undescribed form, but further information is required.

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).

Figure 12. Photomicrographs of (A) Amphileptus sp., (B, C, E, F) Aegyriana paroliva, (D, I, J) Dysteria parovalis nov. spec., (G) Hartmannula cf. angustipilosa, (H, K) Orthodonella shenae, and (L) Telotrochidium sp. after protargol impregnation. (A) Infraciliature of anterior portion; arrows indicate the extrusomes; (B) ventral view of anterior portion; arrow indicates the cytopharynx; (C) ventral view of oral area, arrow marks the three-rowed perioral kineties; (D) left side, arrow marks the shortened left somatic kineties; (E) ventral view, arrows indicate the shortened kineties; (F) ventral view of caudal portion, white arrow indicates the glabrous area, whereas the black arrow points to the podite; (G) ventral view, arrows mark the perioral kineties; (H) ventral view of anterior part, arrow indicates the cytostome; (I) posterior portion, to show the podite; (J) the same specimen but focusing at different level, to show the argyrophilic patch (gland?); (K) ventral view, to show the highly developed cytopharynx (arrow); (L) lateral view, arrow marks the broad aboral wreath of cilia.

Figure 15. Photomicrographs of (A–I, N) Metaurostylopsis rubra, (P) Holosticha sp. and (J–M, O) Thigmokeronopsis magna nov spec. after protargol impregnation. (A) Ventral view of anterior portion in late divisional stage; (B) to show the macronuclei in replication stage (arrow marks the replication band); (C, D) detailed portion of the opisthe, black arrows in (C) and (D) indicate the fronto-terminal cirri; white arrow in (D) points to the ventral row; (E, F) buccal field, white arrow in (E) marks the fronto-terminal row, while double-arrowheads indicate the buccal cirrus; black arrow in (F) points to the long fronto-terminal row; (G, H) ventral view of proter, arrow in (G) marks the fronto-terminal cirral row; (I) ventral view, to show the general pattern of ventral, marginal and transverse cirri; (J) portion of dorsal side, to show the dorsal kineties (arrowheads); (K) ventral view, to show the thigmotactic area, note that the cirri are densely but irregularly arranged (arrows); (L) ventral view of caudal part, arrow indicates the transverse cirri; (M) ventral view of buccal region, white arrow indicates the two fronto-terminal cirri, whereas the black one marks the distal end of adoral zone of membranelles; (N) ventral view in a late divider, to show the newly formed transverse cirri (arrows); (O) to show the fibres connecting to the marginal cirri; (P) dorsal view, to show the large extrusomes (arrowheads).