Metaurostylopsis rubra Song and Wilbert, 2002

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 : 960-966

Metaurostylopsis rubra Song and Wilbert, 2002

( Figures 10D–G , 15A–I, N )

The current population matches the original description very well. We thus supply here only some information derived from recent observation of its morphological features and the morphogenetic process.

Description

Body often more oval than originally reported, size in vivo about 150650 M m. Eight left and six right marginal rows on average; adoral zone about one-third of body length with 45 membranelles; about 12 pairs of cirri in midventral rows, single ventral row extending to about posterior third of cell length with ca 13 cirri; ca 10 fronto-terminal, one buccal, four frontal and five transverse cirri ( Figures 10D , 15E, F, I ). Constantly three dorsal kineties, no caudal cirri.

On the basis of the morphogenetic stages obtained from the present population, formation of the ciliature in Metaurostylopsis rubra can be summarized as follows: (1) The parental oral apparatus is entirely renewed by the proter’s oral primordium. (2) Two sets of fronto-ventral-transverse cirral anlagen give rise to the buccal, fronto-terminal, transverse and anterior most frontal cirri, as well as to the ventral and the midventral rows in both divisional parts. (3) The leftmost frontal cirrus develops from the undulating membrane primordium in both proter and opisthe. (4) Streak II–III generates the other frontal and the buccal cirri. (5) Streaks IV to n-1 give rise to the midventral rows. (6) The short ventral row posterior to the midventral rows originates also from the anlage n-1 (the last but one). (7) The fronto-terminal cirri are formed by the last streak of the fronto-ventral-transverse anlagen. (8) Two anlagen develop within each marginal cirral row, each of which forms a separate marginal row. (9) One anlage develops within each of the three parental dorsal kineties in both dividers. (10) No caudal cirri are differentiated.

Thus the morphogenetic process is very similar to its congener, Metaurostylopsis marina ( Kahl, 1932) Song et al., 2001 ( Song et al. 2001), though some details of this new species remain unknown because certain divisional stages have not yet been observed.

Figures

Figure 10. (A–C) Holosticha sp. and (D–G) Metaurostylopsis rubra after protargol impregnation. (A) Ventral view, arrows mark the fronto-terminal cirri; (B) detailed portion, to show the extrusomes; (C) dorsal view, arrows mark the extrusomes; (D) ventral view, to show general structure of ciliature; (E, F) cells in middle and late divisional stage, arrows in (F) mark the fronto-terminal cirri, arrowheads indicate transverse cirri; (G) macronuclei. Scale bar: 40 Mm.

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).