Dictyocysta
Dictyocysta Ehrenberg, 1854
[ref. ID; 3597]
Lorica pot-shaped, consisting of a cylindrical collar and an ovate bowl; oral margin usually smooth, rarely with spines, generally more or less undulating; collar constructed of one or two rows of windows of which frames usually curve outwardly; bowl often surrounded with fenestrae; aboral end rounded or sometimes pointed; wall single layered, composed of a reticulated structure which is visible or invisible, often with coccoliths attached to the surface. Being characteristic in form and structure, species of this genus are easily distinguished from those of other genera, and are mostly dwellers in warm waters. (ref. ID; 3597)
Type species; Dictyocysta elegans Ehrenberg (ref. ID; 3597)
- Dictyocysta dilatata Brandt (ref. ID; 3597)
- Dictyocysta duplex Brandt (ref. ID; 3597)
- Dictyocysta elegans Ehrenberg (ref. ID; 3597) reported author and year? (ref. ID; 4464)
- Dictyocysta entzii (ref. ID; 4464)
- Dictyocysta lepida Ehrenberg (ref. ID; 3597)
- Dictyocysta magna (ref. ID; 3319)
- Dictyocysta minor Jorgensen (ref. ID; 3597)
- Dictyocysta mitra (ref. ID; 4464)
- Dictyocysta mulleri (ref. ID; 3319)
- Dictyocysta nidulus Kofoid & Campbell (ref. ID; 3597)
- Dictyocysta obtusa Jorgensen (ref. ID; 3597)
- Dictyocysta occidentalis Kofoid & Campbell (ref. ID; 3597, 4046)
- Dictyocysta polygonata Kofoid & Campbell, 1929 (ref. ID; 3544, 3597, 4600)
- Dictyocysta reticulata Kofoid & Campbell (ref. ID; 3597)
- Dictyocysta seshaiyai Krishnamurthy & Santhanam, 1979 (ref. ID; 4669 original paper)
- Dictyocysta verticosa Hada, 1938 (ref. ID; 3597 original paper)
Descriptions
Lorica 1.45 oral diameters in length; collar subcylindrical, slightly narrowing posteriorly, composed of a zone of six quadrate windows, 0.30-0.33 of the total length in height; bowl roundly ovate with a wide end, broadest in the rounded shoulder of 1.2 oral diameters; wall of the bowl having no fenestration, covered with coccoliths. (ref. ID; 3597)
Comments
The species differs from D. polygonata Kofoid & Campbell in possessing closely aggregated coccoliths on the surface of the bowl. (ref. ID; 3597)
Measurements
Length 50-52; oral diameter 35; length of the collar 15-17; greatest diameter of the bowl 42 um. (ref. ID; 3597)
Descriptions
Lorica 1.43 oral diameters in length, oral margin smooth; collar cylindrical, 3.1 of the total length in height, consisting of 6-7 quadrate windows arranged in a single row, their width 1.25 of their height, their vertical beams comparatively wider and straight; bowl broadest at the portion of its anterior 0.2, 1.1 oral diameters in greatest transdiameter; aboral region broadly rounded; wall finely reticulated throughout the lorica even in the collar, provided with one row of 6-7 large, round, subequal fenestrae near the middle of the bowl, of which the upper part has numerous small pores scattered closely and small fenestrae are also present in the aboral region. (ref. ID; 3597)
Comments
The species differs from D. nidulus Kofoid & Campbell in the shorter collar and wider frames and from D. reticulata Kofoid & Campbell in having a minute reticulation appearing even in the frames of the windows on the collar besides in the bowl. (ref. ID; 3597)
Measurements
Length 50-52; oral diameter 35-37; length of the collar 18-20; greatest transdiameter of the bowl 38-40 um. (ref. ID; 3597)
Descriptions
Lorica 1.57-1.66 oral diameters in length; collar cylindrical 3.4-4.0 of the total length in height, consisting of 5-6 rectangular windows arranged side by side, their frames somewhat wide; bowl broadly ovate with a rounded shoulder, its greatest diameter 1.14 oral diameters; aboral end round; wall of the bowl having a median series of 8-9 large fenestrae, posterior one of 5-7 small and an aboral group scattered irregularly, entirely covered with coccoliths, wall of the collar composed of a fine reticulation. (ref. ID; 3597)
There are 5 large windows in the collar. Reticulation is not visible on the posts between the windows (at 188 x); it differs, in this respect, from specimens described by Kofoid & Campbell and Hada. However, the shape of the lorica and number of windows coincide with their descriptions. The bowl, rounded aborally, is agglomerated with coccoliths. (ref. ID; 4046)
Comments
The species differs from D. lepida Ehrenberg in the presence of a cover of coccoliths and the absence of the anterior group of small fenestrae and from D. duplex Brandt in having fenestrae in the bowl. (ref. ID; 3597)
Measurements
Length 55-58; oral diameter 35; length of the collar 20-23; greatest diameter of the bowl 40 um. (ref. ID; 3597)
Length 53, width 35 um. (ref. ID; 4046)
Dictyocysta polygonata Kofoid & Campbell, 1929 (ref. ID; 3544, 3597, 4600)
Descriptions
The lorica is stout pot-shaped, and consists of a cylindrical collar composed of 6-7 rectangular windows standing side by side and of an ovoid bowl with a polygonal reticulation on the surface. (ref. ID; 3544)
Lorica 1.6 oral diameters in length; collar subcylindrical, consisting of a row of 6-7 rectangular windows with rather narrow frames, its height o.35 of the total length; bowl broadly globose or ovate, without fenestration, 1.1-1.2 oral diameters in greatest transdiameter; aboral end rounded; wall composed of a reticulation of rather uniform polygonate meshes. (ref. ID; 3597)
Comments
The species differs from all of the species except D. pulex Brandt in Dictyocysta in the absence of a fenestration on the bowl and from the latter in the shape of meshes of the reticulation in the wall. (ref. ID; 3597)
Measurements
Length 62; breadth 48; oral diameter 40; length of a collar 25 um. (ref. ID; 3544)
Length 55-58; oral diameter 35-36; length of the collar 20; greatest diameter of the bowl 40-42 um. (ref. ID; 3597)
Descriptions
Lorica consisting of a cylindrical collar and a subspherical bowl, its length 1.3-1.5 oral diameters; collar 0.35 of the total length, with a single row of 6-7 rectiangular windows with narrow beams, their height a little greater than their width; bowl stout, broadest at its anterior 0.2, its greatest transdiameter 1.2 oral diameters, aboral region broadly convex conical with a rounded aboral end; wall of the bowl with a rather uniform reticulation which is not seen in the collar, sometimes bearing coccoliths on the surface, having one row of 6-7 large ovate fenestrae in its middle and a posterior row of a few small ones. (ref. ID; 3597)
Comments
The species differs from D. lepida Ehrenberg in the lack of anterior small fenestrae and of a reticulation in the collar and from D. occidentalis Kofoid & Campbell in having narrower frames of windows of the collar on which a reticulation is not visible in this species. (ref. ID; 3597)
Measurements
Length 52-60; oral diameter 35-40 um. (ref. ID; 3597)
Dictyocysta seshaiyai Krishnamurthy & Santhanam, 1979 (ref. ID; 4669 original paper)
Descriptions
The lorica is divisible into bowl and collar portions. The collar possesses a single row of 4 rectangular windows. They are formed by four frames placed at equidistance from each other. The bowl is bulbous but slightly pointed aborally. Agglomeration with foreign particles is noticed both on the bowl and on collar however, on the collar the size of the particles is great. Neither fenestrae nor reticulation is evident on the lorica. (ref. ID; 4669)
Comments
The new species differs significantly from D. elegans lepida (Zeitzschel, 1969). In the nature of the bowl and of the windows, both species are alike. But the number of frames and corresponding number of window are only 4 in our specimens, unlike 5 to 8 and 6 to 7 of Marshall's (1969) and Zeitschel's (1969) specimens respectively. (ref. ID; 4669)
Type locality
October, 1973; Mouth of the Vellar estuary. (ref. ID; 4669)
Type slide
Samples of this species are deposited in the Indian Museum (Holotype ZSI-Reg.No.PL1791) British Museum (Paratype-Reg.No.1976:1:8:1) and the Smithsonian Museum. (ref. ID; 4669)
Measurements
Total length 72.0 to 82.8 um; inner oral diameter 48.5 to 54.0 um. (ref. ID; 4669)
Descriptions
Lorica subcylindrical in the anterior half, posteriorly conical, 1.54 oral diameters in length; oral margin more or less undulating; collar cylindrical, 0.4 of the total length in height, with seven quadrangular windows arranged in a single row, their height as much as twice their width and their vertical beams somewhat curved outwardly; bowl forming an inverted low convex cone below a slight dilation at the middle of the lorica, its greatest diameter 1.1 oral diameters; aboral end rounded; fenestration consisting of several rows of pores becoming gradually smaller to the aboral end and located in the posterior half of the lorica; wall hyaline, reticulation invisible. (ref. ID; 3597)
Comments
The new species differs from D. dilatata Brandt, D. minor Jorgensen, and D. obtusa Jorgensen in the high distinct collar and the stout conical bowl. The new species is characteristic in having a high differentiated collar and a wide clear band in the anterior part of the bowl in spite of reticulation being invisible in the bowl. (ref. ID; 3597)
Type locality
Palao Islands, exceedingly rare. (ref. ID; 3597)
Measurements
Length 57; oral diameter 37; length of the collar 23; greatest diameter of the bowl 43 um. (ref. ID; 3597)