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Pseudoristola Yeh 1987 (radiolarian)

Radiolaria - Nassellaria - Parvicingulidae

PaleoDB taxon number: 620

Original description: Test multicyrtid, conical to subconical, with two to six post-abdominal chambers. Cephalis conical to dome shaped without horn. Thorax and subsequent chambers trapezoidal in outline. Earlier chambers covered with layer of microgranular silica, remaining chambers consisting of single layer of regular to subregular pentagonal and hexagonal pore frames. Each post-abdominal chamber with two to three transverse rows of pore frames. Pore frames slightly variable in size, usually with largest pores along partitions. Test with or without poorly developed circumferential ridges. Final post-abdominal chamber closing and with latticed bulbous expansion.

Remarks Pseudoristola, n. gen., differs from Ristola Pessagno and Whalen (1982) by having a test with pore frames more irregular in shape, by lacking well developed circumferential ridges on post abdominal chambers, and by having its final post-abdominal chamber closing with a large latticed bulbous expansion rather than terminating in an open tubular extension.

Etymology: Pseudoristola pseudo(false) Ristola.

Full reference: K. Y. Yeh. 1987. Taxonomic Studies of Lower Jurassic Radiolaria from East-Central Oregon. National Museum of Natural Science Special Publications 2:1-169

Parent taxon: Parvicingulidae according to P. De Wever et al. 2001

Sister taxa: Caneta, Darvelus, Dictyomitrella, Elodium, Excingula, Mirifusus, Nitrader, Parvicingula, Parvicingulinae, Praeparvicingula, Ristola, Tethysetta, Wrangelliinae

Subtaxa: Pseudoristola durisaeptum, Pseudoristola faceta, Pseudoristola horni, Pseudoristola megaglobosa, Pseudoristola tsunoensis

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Ecology: passively mobile planktonic omnivore