radiolaria - rads_cenozoic - Phormostichoartus fistula

Phormostichoartus fistula

Classification: rads_cenozoic -> Artostrobiidae -> Phormostichoartus -> Phormostichoartus fistula
Sister taxa: P. caryoforma, P. corbula, P. crustula, P. doliolum, P. fistula, P. furcaspiculata, P. marylandicus, P. multiseriatus, P. pitomorphus, P. platycephala, P. schneideri, P. strongi, P. sp.


Citation: Phormostichoartus fistula Nigrini 1977
Rank: species
Basionym: Phormostichoartus fistula
Taxonomic discussion: Nigrini 1977 p.253 pl.1 figs.11-13

Catalog entries: Phormostichoartus fistula

Original description: Shell thick-walled, smooth, subcylindrical, consisting of four segments. Cephalis approximately spherical with well-developed, poreless vertical tube lying along thorax for about half thoracic length; few subcircular pores; no apical horn. Collar stricture indistinct. Thorax short, truncate conical with two or three transverse rows of relatively large subcircular pores. Lumbar stricture and post-lumbar strictures distinct but not pronounced. Sometimes post-lumbar stricture marked by smooth poreless band. Abdomen annular, elongate with five to eight closely spaced transverse rows of large subcircular pores.

(Based on 15 specimens) Total length 110-190 µ; length of cephalis and thorax 36-40 µ; length of abdomen 35-53 µ; length of fourth segment 35-70 µ; maximum breadth 65-83 µ

Fourth segment approximately same width as or narrower than abdomen; pores similar in size and shape to those on abdomen, usually in three or four transverse rows. Segment narrowing to poreless peristome, sometimes with small, poorly developed terminal teeth. In some specimens fourth segment is elongate with more pore rows, often becoming irregular in arrangement and shape. Phylogeny (rw): Uncertain; may be ancestor of Phormostichoartus corbula.
Remarks on original description: Eocene and Oligocene specimens usually incomplete, with fourth segment either broken or not originally developed. Characteristic vertical tube always well developed.




Biogeography and Palaeobiology

Biostratigraphic distribution

Geological Range:
Last occurrence (top): within Neogene Period (2.59-23.03Ma, top in Piacenzian stage). Data source: Lazarus et al. 2015 - "N age group"
First occurrence (base): within Neogene Period (2.59-23.03Ma, base in Aquitanian stage). Data source: Lazarus et al. 2015 - "N age group"

Plot of occurrence data:


Nigrini, C. A. (1977). Tropical Cenozoic Artostrobiidae (Radiolaria). Micropaleontology. 23(3): 241-269. gs


Phormostichoartus fistula compiled by the radiolaria@mikrotax project team viewed: 30-9-2022

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