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Rhipidodendron Stein, 1956 (ref. ID; 3748)

[ref. ID; 1618]
Similar to Cladomonas, but tubes are fused lengthwise; fresh water. (ref. ID; 1618)

[ref. ID; 3748]
The genus Rhipidodendron was erected by Stein (1956) for colonial colorless flagellates with 2 equal length flagella in which the cells were embedded in granular matrix material. Stein described only a single species of Rhipidodendron, R. splendidum, which had fan-shaped colonies composed of dichotomously branched tubes, each of the ultimate ones containing a flagellate at its anterior end. (ref. ID; 3748)
  1. Rhipidodendron huxleyi Saville-Kent, 1882 (ref. ID; 3748)
  2. Rhipidodendron splendidum Penard (ref. ID; 2683)
  3. Rhipidodendron splendidum Stein, 1956 (ref. ID; 3748) reported year? (ref. ID; 1618, 3343, 3517)

Rhipidodendron huxleyi Saville-Kent, 1882 (ref. ID; 3748)


See R. splendidum.

Rhipidodendron splendidum Penard (ref. ID; 2683)


This is a colonial flagellate, sometimes alternatively classified as a chrysomonad alga. The cells are located at the ends of long gelatinous tubes which are arranged in flattened contiguous bundles. (ref. ID; 2683)

Rhipidodendron splendidum Stein, 1956 (ref. ID; 3748) reported year? (ref. ID; 1618, 3343, 3517)


Oval. (ref. ID; 1618)

[ref. ID; 3748]


On the basis of the structural similarity of the cells of R. splendidum and Spongomonas spp. when free from the colony matrix, Hartmann & Chagas (1910) transferred the former species to be genus Spongomonas and combined the 3 species of Spongomonas described by Stein (1878) under the name S. uvella. They retained "Spongomonas splendida" as a separate species mainly because the granules in the colony matrix were always smaller than those in S. uvella. Although the present observations on the basic similarity of cell structure in R. splendidum and S. uvella support and considerably extend those of Hartmann & Chagas, it has been decided to retain the genus Rhipidodendron for species forming fan-shaped colonies built of tubes and to refer to the genus Spongomonas those forming less well defined colonies not built of tubes. There appears to be no overlap between these 2 basic types and the distinction between them is well marked at a very early stage of growth since even solitary cells of Rhipidodendron are cylindrical in shape and completely surrounded by a tube of spherules. It is possible that characters such as the presence or absence of a nuclear sac and detained differences in the structure of the flagellar apparatus may also become useful taxonomically when more species have been investigated. With regard to the taxonomy of the genus Rhipidodendron, the species described by Saville-Kent (1882) as Rhipidodendron huxleyi differs from R. splendidum in possessing only 4 and not an indefinite number of tubules in each branch of the colony and in having more symmetrically branched colonies. The species investigated here may therefore be clearly identified as Stein's R. splendidum because of the rather irregular shape of the larger colonies which have up to 20 tubes in each branch. Since, however, younger colonies are more regular in form and have mostly 4 tubes per branch, it is possible that the 2 taxa may only be growth forms of one species, though it should also be pointed out that very large richly branched colonies of R. huxleyi of the sort figured by Saville-Kent (1882) have not been seen. Work on material in culture would therefore seem to be necessary for a definite solution to this problem. (ref. ID; 3748)


Body about 13 um long; flagella about two to three times body length; fully grown colony 350 um high. (ref. ID; 1618)
Length of cells 10-12 um. (ref. ID; 3343)