The Genus Cenchridium Ehrenberg*
[Communicated by Prof. V. J. Chapman, and read before Auckland Institute, July 20, 1955; received by the Editor June 23, 1955.]
Four species of the Genus Cenchridium are known up to the present; two of these being reported from the Southern Ocean. Six new species are now described from the shore waters of the Hauraki Gulf. In four of these empty tests only were found. but in the other two the living organisms were present. The new species are C. verum, C. armatum C. spectabile C. takapuniense, C. p [ unclear: ] rum and C. novae-zelandiae.
Ehrenberg, in 1845, described the genus Cenchridium on the species C. sphaerula and placed it in the Foraminifera. He had the empty test only, so knew nothing of the organism that inhabited it.
Stein (1883) added two new species, C. rugulosum and C. tridactylum. At the same time he transferred a species described by Williamson as Entosolenia globosa to the genus Cenchridium and illustrated a variety of it. He treated these as organisms of uncertain position.
Schiller (1933) placed the genus in the Desmokontae of the Dinoflagellata and in the family Prorocentraceae of the Thecales. He did not discuss his reasons for this placement, but they were apparently based on the strong similarity between the test of Cenchridium and the theca of Exuviella, in the Prorocentraceae. At the same time Schiller pointed out that for Cenchridium nothing was known of the test structure, flagella and locomotion, chromatophores, nutrition, reproduction, geographical distribution and distribution in depth.
Of the four species, C. globosum and C. sphaerula are known from the south seas only, C. rugulosum from the Adriatic, and C. tridactylum from the south seas and the Mediterranean. None has been reported since the original papers discussing them.
Six new species have been found in shore waters of the Hauraki Gulf, near Auckland, New Zealand. Three of these were taken at low tide in tows made from the shore, using a 24 mesh silk bolting cloth net. The remaining three species were collected from the water that seeped out of the sand into holes dug at low tide, mid tide, and high tide levels. On Takapuna beach, where the collections were made from the sand, except during spring tides, there is about 100-120 feet of sand exposed between high and low tide marks. The tide here varies around seven feet. The water was dipped from the holes into the tow-net and the sand allowed to settle in the vial before decanting into a small jar. This procedure was followed primarily to collect the sand-dwelling Dinoflagellates, but it also yielded Cenchridium. If done regularly throughout the seasons, it no doubt would yield many more undescribed species. Judging from the collection conditions for the present six species Cenchridium is a genus of sandinhabiting organisms.
Tests only were found for four of the new species. For the other two species both empty tests and ones containing the live organism were collected. The organism, as may be seen in Fig. 8, is quite obviously amoeboid, without any Dinoflagellate characters and without flagella or chromatophores. The protoplast
[Footnote] * This work was carried out during the tenure of a Fulbright research award to New Zealand and while attached to the Botany Department of Auckland University College.
may or may not fill the test, is usually dark granular and with one or more vacuoles. The filipodia are simple or branched.
While the tests are variously shaped, they are all flattened or narrower in one dimension and usually present the broad surface to view. In three species the test wall is thickened along the margin in the narrow diameter, and thus suggests a suture uniting two valves. Attempts to separate the test into two valves failed, however, the test breaking irregularly and across the thickened portions. The character of a test composed of two valves, which was figured for C. sphaerula, and which was probably a deciding point in Schiller's placement of this genus, is apparently a false one. The line of thickening, raphe or pseudosuture, is homogeneous with the rest of the test, and shows no line of regular dehiscence. The tests are calcareous and either granular with various kinds of pores, or glassy-clear and with or without pores.
Since this is a very poorly known genus, characters of specific importance are not known. Thus in the following descriptions of the new species everything has been considered, including dimensions of questionable value. In C. spectabile the orifice tube showed distinct added sections, hence overall length may not be of any specific value. Likewise in those species bearing external arms or processes, the length of these structures is of doubtful usefulness, since they may readily be shortened through breakage.
Whether these organisms are to be considered as having become straight or single-chambered, with an invaginated orifice, and thus to be replaced in the Lagenidae of the Foraminifera can only be decided by students of that group. Otherwise they seem more aptly classed as members of the order Testacea of the Sarcodina, though here they do not have the thecal characters of any of the present families except possibly of the Gromiidae.
Cenchridium Ehrenberg, 1845
C. sphaerula Ehrenb. Fig. 1, after Ehrenberg.
Test broadly ovoid to nearly circular in face view, elliptical in side view. Orifice tube curved and extending nearly to the posterior end. Seattered pores present on the margins only. Empty test only known and no dimensions given. Known only from the Southern Ocean.
C. globosum (Williamson) Stein. Fig. 3, a, after Williamson (= Entosolenia globosum Williamson); b, after Stein.
Test ovoid to pyriform in face view. Orifice tube tapered from orifice to free end and not quite reaching to one-half the test length. Pores scattered over the posterior half. No dimensions given. A contracted protoplast was observed in the pyriform variant by Stein. Known only from the Southern Ocean.
C. rugulosum Stein. Fig. 2, after Stein.
Test pentagonal in face view, with a flat anterior end, gradually diverging sides to two-thirds the length, which then converge posteriorly to form a pointed artapex. Orifice tube about one-half the test length, with free end obliquely truncated, so that it is apparently pointed. Test wall thick, with pores in the anterior half, and irregularly warty-wrinkled posteriorly. No dimensions given. Known only from the Adriatic Sea.
C. tridactylum Stein. Fig. 4, after Stein.
Test pyriform-angular in face view, bearing laterally just below the broadest diameter two and on the antapex one solid spine-like process. Orifice tube straight,
Text-Fig. 1.—Fig. 1—C. sphaerula, face and side views; after Ehrenberg. Fig. 2—C. rugulosum, face view; after Stein. Fig. 3—C. globosum, face views; a after Williamson; b, after Stein. Fig. 4—C. tridactylum, face view; after Stein. Figs. 5-7—C. varum, sp. nov., face views. X 700. Figs. 8-10—C. spectabile sp. nov. Fig. 8, X 350; Figs. 9, 10, side and face views, X 700.
nearly one-half the test in length and obliquely truncated at the free end. No dimensions given. Known from the Mediterranean and the Southern Ocean.
C. varum sp. nov. Figs. 5-7, X 700.
Test 4-7-angled in face view, cylindrical with rounded apices in side view, angular to broadly rounded-angular; bearing on each side in the anterior one-half or one-third a single, tapered, tubular arm which may or may not terminate in a bulbous inflation. Orifice tube about one-third the test length, straight; free margin straight or slightly flared and minutely toothed. Test glass-clear or with flocculent granulations and without pores. Known from empty tests only.
Test: Length 33-47μ, width 29-55μ, thickness 12 8-20μ.
Orifice Tube: Length 8.5-13.6μ, width 2.8-3 5μ.
Arms: 8.5-17μ long.
Collected: Fig. 5, 20 March, 1955, from sand, low tide level. Fig. 6, 27 February, 1955, from sand, mid tide level. Fig. 7, 20 March, 1955, from sand, high tide level. Takapuna Beach, Auckland, N.Z.
While the forms figured are being treated as of one species, Figs. 6 and 7 are quite similar, but Fig. 5 could conceivably be a different species. Its dimensions were L. 41μ, W. 55μ, th. 20μ, tube 13.6μ.
C. armatum sp. nov. Fig. 11, X 700.
Test spatulate to slightly panduriform in face view, cylindrical with rounded apices in side view, with the wall at the anterior end greatly thickened and bearing laterally on each side a single retrorsely bent, solid, spine-like process. Orifice tube about one-third the test length, straight with a minutely serrate free margin. Test glass-clear and without pores.
Test: Length 55μ, width 24μ, thickness 15.6μ.
Orifice Tube: Length 15.6μ, diameter 4.2μ.
Arms: 12.8μ long.
One empty test seen.
Collected: 20 March, 1955, from sand at high tide level. Takapuna Beach, Auckland, N.Z.
C. spectabile sp. nov. Fig. 8, X 350; figs. 9, 10, X 700.
Test broadly ovoid in face view, narrowly pyriform in side view. Anterior pole straight or undulate, posterior pole emarginate with a prominent thickened rim about the emargination. Orifice tube straight, nearly one-half the test length, flaring at the free end with a coarsely or sinuately toothed margin. Test glassclear, without thickening around the margin, with numerous irregularly spaced pores limited to the posterior one-third and the lateral margins to within one-third of the anterior end.
Test: Length 85μ, width 64μ, thickness 47μ.
Orifice Tube: Length 35.5μ, diameter 6.7μ.
Collected: 23 February, 1955, from sand at low tide level, Takapuna Beach, Auckland, N.Z.
As may be seen in Fig. 8, the organism filled the test little more than half. The orifice tube in this species showed two growth extensions, or perhaps replacement of sections previously broken off, hence dimensions of the tube may be of no value as a specific character.
C. takapuniense sp. nov. Fig. 12, X 700.
Test pentagonal in face view with anterior end broadly rounded, lateral margins nearly parallel, and posterior end abruptly convergent to a rounded
apiculation. In side view cylindric with tapered anterior end and rounded poles Orifice tube about one-fourth the test length, flaring at both the attached and free ends. The free end obliquely truncated with a coarsely serrate or blunt toothed margin. Test finely granular but transparent, with scattered circular pores at the margins but not in the marginal band of thickening Known only from one empty test.
Test: Length 97μ, width 59μ, thickness 25μ.
Orifice Tube: Length 27.5μ, diameter 4.2μ.
Collected. 11 February, 1955, in tow taken at low tide. Takapuna Beach, Auckland, N.Z.
C. pyrum sp. nov. Figs. 13, 14, X 350.
Test ovoid to pyriform in face and side views, with prominent glassy lips at the orifice. Test wall heavy and nearly opaque, the opacity being due to the many line-like micropores that traverse the thick wall. Test with a line of thickening around the margin and a ring of thickening on the posterior pole. Orifice tube about one-fourth the test length, flared at the free end and with a minutely toothed margin.
Test: Length 205μ, width 150μ, thickness 120μ.
Orifice Tube: Length 48μ, diameter 5μ
Collected: 26 February, 1955, in tow at high tide. Takapuna Beach, Auckland, N.Z.
The living protoplast completely filled the test and contained four vacuoles.
C. novae-zelandiae sp. nov. Figs. 15-17 X 700.
Test broadly ovoid in face view, narrowly so in side view. Posterior end with a short, blunt process. Margin of orifice thickened and somewhat prolonged as lips, the thickening extending around the test in its broadest diameter. Test granular but transparent with many irregular pores and pits scattered over the entire surface. Orifice tube straight, about two-fifths the test length The free end slightly flared with an irregularly blunt toothed margin.
Test:. Length 71μ, width 55μ, thickness 42.5μ.
Orifice Tube. Length 28.5μ, diameter 5.9μ
One empty test seen.
Collected: 11 February, 1955, in tow at low tide. Takapuna Beach, Auckland, N. Z.
Ehbenberg, C. G., 1845. Neue Untersuchungen uber das kleinste Leben als geologischen Moment, mit kurzer characterisk von 10 neue Genera. [ unclear: ] u 66 neue Arten Monatsb der K. Akad. zu Berlin
Schiller, J. 1933-1937 Dinoflagellatae in L. Rabenhorst, Kryptogamenflora von Deutschland, Oesterreich und der Schweiz. 10 (1933) Teil 1. 1-617; Teil 2, Lf. 1 (1935); 1-160; Lf. 2 (1935) 161-320; Lf 3 (1937): 321-480; Lf. 4 (1937): 481-590. Leipzig
Stein, F. R. Von, 1883. Der Organismus der Infusionsthiere nach eigenen Forschungen in systematischer Reinenfolge bearbeitet III. Abt. H. Halft Die Naturgeschichte der Arthrodelen Flagellatum. Lerpzig.
Prof R. H. ThompsonUniversity of Kansas
U. S. A.