Protocruzia
Protocruzia Da Cunha, 1915 (ref. ID; 4905)
Order Heterotrichida Stein, 1859: Family (?)Spirostomidae Stein, 1867 (ref. ID; 4905)
- Protocruzia adhaerens Mansfeld, 1923
See; Protocruzia contrax (ref. ID; 4905)
Syn; Blepharisma minima Lepsi, 1926 (ref. ID; 1621)
- Protocruzia contrax (Mansfeld, 1923) (ref. ID; 4905 redescribed paper)
Syn; Blepharisma minima Lepsi, 1926 (ref. ID; 4905); Protocruzia adhaerens Mansfeld, 1923 (ref. ID; 4905); Protocruzia depressa Ammermann, 1968 (ref. ID; 4905); Protocruzia tuzeti Villeneuve-Brachon, 1940 (ref. ID; 4905)
- Protocruzia depressa Ammermann, 1968
See; Protocruzia contrax (ref. ID; 4905)
- Protocruzia tuzeti Villeneuve-Brachon, 1940 (ref. ID; 4905, 7568) reported author and year? (ref. ID; 191)
See; Protocruzia contrax (ref. ID; 4905)
Protocruzia contrax (Mansfeld, 1923) (ref. ID; 4905 redescribed paper)
Synonym
Blepharisma minima Lepsi, 1926 (ref. ID; 4905); Protocruzia adhaerens Mansfeld, 1923 (ref. ID; 4905); Protocruzia depressa Ammermann, 1968 (ref. ID; 4905); Protocruzia tuzeti Villeneuve-Brachon, 1940 (ref. ID; 4905)
Improved diagnosis
Marine Protocruzia in vivo 15-50 um, about 1:2 bilaterally flattened with pointed anterior end; ca. 10 dikinetid somatic kineties, one macronuclear complex with 6-11 close-set, globe-like nodules; 6 adoral membranelles. (ref. ID; 4905)
Redescription
Cell size variable among populations and depending on feeding regime (after culture could be twice as long as it was). Body shape generally stable though contractile slightly (in small cells) to evidently (for large ones) with frequent jerks in buccal portion. Length:width about 1.5-2:1; bilaterally ca. 1:2 flattened with right side used as "ventral" surface to bottom. Outline from lateral view variable rom slender to broadly kidney-shaped, yet basically Colpoda-like with snout-shaped, pointed anterior end ventrally; posterior end widely rounded. Ventral margin slightly convex, anterior portion distinctly indented and forming buccal concave; dorsally conspicuously convex. Cell sensitive to fixation or stimulation, pellicle thin, very fragile, no contractile granules visible. Cytoplasm hyaline, colourless or slightly greenish, often with several to many shining globules (2-4 um across) and a few food vacuoles containing diatoms or other flagellates; frequently one large food vacuole immediately beneath cytopharynx. 6-11 (n=5) spherical macronuclear segments always closely together forming a single complex located in mid-body. Micronucleus unrecognizable (neither in vivo nor after protargol impregnation). Cysts once observed plentiful in culture: about 10-14 um in diameter with macronuclei located centrally; cyst wall thick and colourless (ca. 1.5 um), outer layer always yellow-brownish because of presence of belt-like unknown structure. Movement lazily, usually very slowly crawling on substrate, or completely silent for rather long periods when feeding. 9-12 somatic kineties comprising dikinetids, which are limited within right side while reduced entirely on left side forming a large naked "dorsal" surface (left side). 2-3 ciliary rows "overgrowing" on both margins when viewed from left side. Kineties slightly spiral and extending from pole to pole except some ventral (postoral) ones, which shortened anteriorly around cytostome. Cilia about 7-9 um long, never stiff or cirrus-like, no caudal cilia. Buccal apparatus inside conspicuous oral cavity, located in anterior 1/3 of cell. Always 6 adoral membranelles each with 4 basal body rows, cilia about 7-8 um long; kineties in membranelle 1 (anterior-most one) often separated into 2 parts and thus appeared as two narrow membranelles with 2 kinety rows each. Paroral membrane on right, posteriorly curved, composed of zigzag row of basal bodies. (ref. ID; 4905)
Remarks
As to the author's knowledge, the species of this genus, with quite a few potential synonyms, have never been critically revised and the systematic position of this genus remains unknown as incertae sedis (q.v. Corliss 1979). According to the general morphology and infraciliature, viz. the buccal apparatus and dikinetid somatic ciliature, it seems to be an intermediate form between heterotrichs and colpods (?). We tried to impregnate this organism with Chatton-Lwoff method, yet failed to get any trace of silverline system. So it might be reasonable to keep it temporarily under the traditional Heterotrichida until further support is available. A great confusion with the identification of this species has been caused possibly by the previous statements about the cell size and contraction of the body. Both in the original and the following reinvestigation (Mansfeld 1923; Kahl 1932), the size was stated consistently as being small (15-25 um long) and the cell being highly contractile. In both population we got, however, the cell size varies within quite a wide range in field samples (newly obtained) and after culture (the small population varied from 15 to 40 um, while the large one from 30-55 um in length). In two populations newly collected, the cells were 15-25 vs. 30-40 um long. However, there was no visible difference at living and infraciliature levels. Alike is the situation of body contraction, according to our observations, this feature is evidently depending on the cell size and the expression of observers. Otherwise, both the JS- and QT-populations correspond very well, in terms of general morphology and behaviours, with the original report (Mansfeld 1923) and Kahl's redescription (1932), so we believe that the identification of our populations is pretty certain. Protocruzia adhaerens Mansfeld, 1923 could be distinguished from P. contrax only in being less contractile and having larger size (40-60 vs. 15-25 um; q.v. Kahl 1932). Because of this, we propose that those two forms should be conspecific and thus P. adhaerens be considered as a junior synonym of P. contrax. Compared with the population studied here, Protocruzia tuzeti Villeneuve-Brachon, 1940 is characterized by "...30-42 um with 10-11 somatic kineties, 5+1 membranelles each with 2-4 kineties" (Villeneuve-Brachon 1940; Groliere et al. 1980) and reveals virtually no difference. It is, therefore, identified with P. contrax. In 1968, Ammermann described a new form from the North Sea (Germany), Protocruzia depressa, which differs from P. contrax in its larger size (40-50 um long) and in having fewer somatic kineties on the right side (7 ones dorso-ventrally according to his illustration). Since some ciliary rows on cell margins might be overlooked, and since the number of kineties could be population-dependent, we consider P. depressa as being conspecific with P. contrax. (ref. ID; 4905)
Neotype specimens
1 neotype as a slide of protargol impregnated specimens has been deposited in the Protozoological Laboratory, College of Fisheries, Ocean University of Qingdao, Qingdao, China. (ref. ID; 4905)
Protocruzia tuzeti Villeneuve-Brachon, 1940 (ref. ID; 4905, 7568) reported author and year? (ref. ID; 191)
See
Protocruzia contrax (ref. ID; 4905)
Descriptions
The ultrastructural study. (ref. ID; 7568)