radiolaria - rads_cenozoic - Stichopilium bicorne radiolaria - rads_cenozoic - Stichopilium bicorne

Stichopilium bicorne

Classification: rads_cenozoic -> Theoperidae -> Stichopiliidae -> Stichopilium -> Stichopilium bicorne
Sister taxa: S. bicorne, S. variabilis, S. sp.


Citation: Stichopilium bicorne Haeckel 1887
taxonomic rank: species
Basionym: Stichopilium bicorne
1887 Stichopilium bicorne - Haeckel p. 1437; pl. 77, fig. 9
1966 Stichopilium bicorne - Benson p. 422-424; pl. 29, figs. 1-2
1974 Coracalyptra sp. aff. C. kruegeri - Renz p. 790; pl. 16, fig. 11
1976 Stichopilium bicorne - Renz p. 125-126; pl. 4, fig. 9
1977 Stichopilium bicorne - Molina-Cruz p. 337; pl. 7, fig. 14
1979 Stichopilium bicorne - Kling p. 311; pl. 2, figs. 11-12
1979 Stichopilium bicorne - Nigrini and Moore p. N91-N92; pl. 26, figs. 1a-1b
1981 Stichopilium bicorne - Takahashi and Honjo p. 153; pl. 9, fig. 11
1983 Stichopilium bicorne - Benson p. 508
1987 Stichopilium bicorne - Bjørklund and de Ruiter pl. 6; fig. 23
1987 Stichopilium bicorne - Boltovskoy and Riedel p. 101; pl. 6, fig. 5
1991 Stichopilium bicorne - Takahashi p. 119; pl. 39, figs. 13-19
1995 Stichopilium bicorne - van de Paverd p. 216; pl. 75, fig. 1
1998 Stichopilium bicorne - Boltovskoy Fig. 15.161
Taxonomic discussion: Haeckel 1887 p.1437 pl.77 fig.9 ; Neogene; Triacartus bicorne Haeckel

Catalog entries: Stichopilium bicorne

Original description: Shell conical, with three slight strictures. Length of the four joints = 4: 14: 5: 3. Cephalis large, conical, with two stout pyramidal, divergent horns of twice the length. From its base (in the middle of the collar stricture) arise three internal, downwardly divergent ribs, which are prolonged on the outside of the upper half of the thorax into three stout, pyramidal, lateral spines (similar to the horns). The fourth joint, with wide open mouth, was the broadest, but not fully developed in the single specimen observed. Pores subregular, hexagonal, with thin bars.
Remarks on original description: Haeckel listed Stichopilium bicorne under the subgeneric name Triacartus, but did not include the subgeneric name in the species name.[comment from RadWorld database]


Published descriptions

Benson 1966 - Stichopilium bicorne

Cephalis smooth, cap-shaped, separated from thorax by a change in contour, but in most specimens the apical-lateral arches and the ventral arch are represented by ribs which occupy slight furrows separating the cephalis from small, dorsal and ventral lobate swellings of the proximal portion of the thorax; pores of cephalis small, equal, subcircular to polygonal, regularly arranged. Two prominent, straight, nearly equal, three-bladed cephalic horns lying in the sagittal plane correspond to the dorsally ascending apical horn and ventrally ascending vertical horn. The former extends from the apical bar which in its upper portion above the junction with the apical-lateral arches is a dorsal rib in the wall of the cephalis and in its lower portion is free within the cephalic cavity. The latter horn extends from and is collinear with the vertical bar which joins with the ventral arch. The dorsal and primary lateral bars extend as ribs in the thoracic wall and are prolonged into heavy, equal, three-bladed, wing-like spines which are generally straight and diverge downward but are nearly horizontal in a few specimens; spines latticed proximally in a few tests. Thorax pyramidal with slightly concave sides between the thoracic ribs in its proximal portion; its distal portion circular in section, campanulate or inflated cylindrical; the wall of the thorax is extended outward where each of the three basal spines originate, thus giving the appearance of three latticed wings originating from the middle portion of the thorax. Number of abdominal segments variable from none to at least two; these joints separated from one another and the thorax by distinct constrictions which are generally occupied by continuous internal septal rings. Abdominal joints cylindrical, inflated, truncate conical or campanulate. Surface of thorax and abdominal joints smooth. Pores of these joints similar, of equal size, small, hexagonal to subcircular, hexagonally arranged in transverse rows.

Measurements: based on 10 specimens from stations 27, 34, 46, 60, and 64: length of test 98-193 m, maximum breadth (thoracic or abdominal joints) 80-138 µm; length of cephalis 21-25 µm, of thorax 62-102 µm, of first abdominal joint 25-49 µm; breadth of cephalis 20-31 µm, of thorax (distal portion) 83-111 µm; length of apical horn 14-49 µm, of vertical horn 15-37 µm, of basal spines 12-53 µm.

Remarks: There is no doubt that the Gulf species is identical with Stichopilium bicorne Haeckel. Campbell (1954, p. D136) states that Stichopilium Haeckel (1882, p. 439) is an objective synonym of Triacartus Haeckel (1882, p.437) and that the type species of the latter is Stichopilium cortina Haeckel (1887, p. 1437), an unfigured species. Earlier, however, Frizzell and Middour (1951) designated S. bicorneas the type species of Stichopilium.I agree with the latter designation as well as with Haeckel's (1887, p. 1436) first revision in which Triacartus is placed in synonymy with Stichopilium, the former becoming a subgenus under the latter.

Distribution: This species is cosmopolitan but very rare in the Gulf. It is absent at stations 90, 95, 99, 130, 191, 194, and all those to the north. Its absence at most of the marginal localities indicates its preference for more nearly oceanic offshore waters. Its very rare occurrence indicates that it does not respond significantly to upwelling in the Gulf. Haeckel (1887, p. 1437) reported this species from the central Pacific at Challenger station 271.Its absence at high latitudes indicates that it is a tropical species. \ From: Benson, 1966, p. 422-424; pl. 29, figs. 1-2:Stichopilium bicorne HaeckelStichopilium bicorne Haeckel, 1887, Challenger Rept., Zool., vol. 18, p. 1437, Pl. 77, fig. 9.

Biogeography and Palaeobiology

Biostratigraphic distribution

Geological Range:
Last occurrence (top): Extant. Data source: Lazarus et al. 2015 - "R age group"
First occurrence (base): within Quaternary Period (0-2.59Ma, base in Gelasian stage). Data source: Lazarus et al. 2015 - "R age group"

Plot of occurrence data:


Benson, R. N. (1966). Recent Radiolaria from the Gulf of California. Thesis, Minnesota University. 1-577. gs

Benson, R. N. (1983). Quaternary radiolarians from the Mouth of the Gulf of California, Deep Sea Drilling Project Leg 65. Initial Reports of the Deep Sea Drilling Project. 65: 491-523. gs

Bjørklund, K. R. & de Ruiter, R. (1987). Radiolarian preservation in eastern Mediterranean anoxic sediments. Marine Geology. 75: 271-281. gs

Boltovskoy, D. & Riedel, W. R. (1987). Polycystine Radiolaria of the California current region: Seasonal and geographic patterns. Marine Micropaleontology. 12(1): 66-104. gs

Boltovskoy, D. (1998). Classification and distribution of south Atlantic recent polycystine Radiolaria. Palaeontologia Electronica. -. gs

Haeckel, E (1887). Report on the Radiolaria collected by H.M.S. Challenger during the years 1873-1876. Report on the Scientific Results of the Voyage of H.M.S. Challenger during the years 1873-1876. 18: 1-1803. gs O

Kling, S. A. (1979). Vertical distribution of polycystine radiolarians in the central North Pacific. Marine Micropaleontology. 4(4): 295-318. gs

Molina-Cruz, A. (1977). Radiolarian assemblages and their relationship to the oceanography of the subtropical southeastern Pacific. Marine Micropaleontology. 2(4): 315-352. gs

Nigrini, C. A. & Moore, T. C. Jr. (1979). A guide to modern Radiolaria. Cushman Foundation for Foraminiferal Research, Special Publication. 16: 1-260. gs O

Renz, G. W. (1974). Radiolaria from Leg 27 of the DSDP. Initial Reports of the Deep Sea Drilling Project. 27: 769-841. gs O

Renz, G. W. (1976). The distribution and ecology of Radiolaria in the central Pacific: plankton and surface sediments. Bulletin of the Scripps Institution of Oceanography. 22: 1-267. gs

Takahashi, K. & Honjo, S. (1981). Vertical flux of Radiolaria: A taxon-quantitative sediment trap study from the western tropical Atlantic. Micropaleontology. 27(2): 140-190. gs

Takahashi, K. (1991). Radiolaria: Flux, ecology, and Taxonomy in the Pacific and Atlantic. Ocean Biocoenosis Series. 3: 1-301. gs

van de Paverd, P. J. (1995). Recent Polycystine Radiolaria from the Snellius-II Expedition. Thesis, Free University Amsterdam. 1-351. gs


Stichopilium bicorne compiled by the radiolaria@mikrotax project team viewed: 8-12-2023

Taxon Search:
Advanced Search

Short stable page link: Go to to create a permanent copy of this page - citation notes

Add Comment

* Required information
Captcha Image
Powered by Commentics


No comments yet. Be the first!