rad_org Dictyophimus bicornis img2982.jpg
rad_org Dictyophimus bicornis img2983.jpg
rad_org Dictyophimus bicornis img2982.jpg
rad_org Dictyophimus bicornis img2983.jpg
1862b Lithomelissa bicornis - Ehrenberg p. 300; 1873 p. 297, pl. 2, f. 7
1967 Dictyophimus bicornis - Petrushevskaya p. 72-3; fig. 41
From Suzuki Paleotax db:
1887 Dictyophimus (Lamprotripus) bicornis n. sp. Haeckel p. 1200
Catalog entries: Dictyophimus bicornis
Original description: Shell thorny, with deep collar stricture. Relative length of the two joints = 2: 3, breadth = 2: 3. Cephalis nearly as large as the thorax, subglobular, with numerous small, circular pores, and two divergent pyramidal horns of half the length (a major occipital and a minor frontal horn). Thorax three-sided pyramidal, with larger irregular pores and three serrate ribs, which are prolonged into three prismatic spiny feet of half the length. (Differs from the similar Dictyophimus sphœrocephalus, Pl, 57, fig. 10, mainly in the double horn and the spinulate feet.)
Cephalis 0.05 long, 0.05 broad; thorax 0.08 long, 0.07 broad. [dimensions in mm]
Remarks on original description: There was no illustration of this species in Haeckel (1887)
Haeckel listed Dictyophimus bicornis under the subgeneric name Lamprotripus, but did not include the subgeneric name in the species name.
Petrushevskaya 1968 - Dictyophimus bicornis Skeleton consisting of two portions. First segment, cephalis, with small apical horn, needle Vert, and some supplementary needles; not sharply delimited from second segment in region of their junction are irregular swellings, as in D. gracilipes. Width of first segment half that of second. Second segment usually closed below. Pores rounded, somewhat irregularly shaped, smaller, on first segment while on lower surface of second segment very large. Pores disposed irregularly. Five to six pores located in spaces between points of emergence of needles D and L or LT and L1 through wall of second segment. Internal skeleton consisting of usual basic elements (needles MB, D, LT and L1, A, and Vert). These elements closely fused to walls of shell. Needles D, LT and L1 passing to outside approximately at middle of second segment. Diverging laterally below at fairly obtuse angle. Dimensions: Length of first segment (externally) about 15 μ, width 3340 μ; length of second segment up to 60 μ, width 55 63 μ. Location: Found by Ehrenberg in sediments near Greenland. Haeckel (1887) reports this species from sediments of temperate zone of North Atlantic, but unfortunately does not provide a drawing of the specimen he found. Encountered in our material in almost all samples of Antarctic sediments in both Indian and Pacific Ocean sectors, but shells are few. Not encountered in tropical-zone sediments. This species was encountered rather more frequently in our North Atlantic material than in the Antarctic samples. Notes: The Antarctic specimens differ slightly from the North Atlantic specimens by their smaller number of larger pores. Our species is most similar to D. gracilipes. The complex junction of the first and second segments is very similar, the second segment in both is usually closed, and the needles of the basal tripod in both species project to the outside lateral to the second segment. D. gracilipes and D. bicornis differ in that in D. bicornis the pores are larger and fewer and also the needles of the basal tripod are weaker and shorter; they pass through the wall of the second segment higher up and are directed somewhat more horizontally than in D. gracilipes. However, if we compare our species with the typical species of genus Lithomelissa Ehr., 1847 (those similar to L. thoracites) and with Dictyophimus gracilipes (type species of genus Dictyophimus), it is clear that in the general construction of the shell this species is closer to Dictyophimus than to Lithomelissa.
Published descriptions
Geological Range:
Last occurrence (top): Extant. Data source: Lazarus et al. 2015 - "R age group"
First occurrence (base): within Quaternary Period (0.00-2.59Ma, base in Gelasian stage). Data source: Lazarus et al. 2015 - "R age group"
Plot of occurrence data:
Ehrenberg, C. G. (1862a). Über die Tiefgrund-Verhältnisse des Oceans am Eingange der Davisstrasse und bei Island. Monatsberichte der Koniglichen Preussische Akademie der Wissenschaften zu Berlin. 1861: 275-315. gs Ehrenberg, C. G. (1874b). Grössere Felsproben des Polycystinen-Mergels von Barbados mit weiteren Erläuterungen. Monatsberichte der Koniglichen Preussische Akademie der Wissenschaften zu Berlin. 1873: 213-263. gs Petrushevskaya, M. G. (1968c). Radiolarians of orders Spumellaria and Nassellaria of the Antarctic region (from material of the Soviet Antarctic Expedition). In, ANdriyashev, A. P. & Ushakov, P. V. (eds) Biological Reports of the Antarctic Expedition (1955-1958). Academy of Science of the USSR. Zoological Institute, 3: 2-186. gs Missing or ambiguous references: Ehrenberg 1862;References:
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Dictyophimus bicornis compiled by the radiolaria@mikrotax project team viewed: 22-7-2026
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