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Pseudodictyophimus gracilipes multispinus Bernstein, 1934

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In the northern parts of the Kara Sea radiolaria, very similar to D. gracilipes Bailey was found. It differs, however, through some features of the skeletal construction. The fundamental differences between this species and D. gracilipes, and equally its characteristic features are its greater number of skeletal spines. Accordingly it was named by me D. multispinus. The skeleton of D. gracilipes has four main spines : apical (A); two lateral, right and left (Lr and Ll); dorasl (D) and one additional vertical (v). Regarding these spines in D. multispinus the following characteristics are also given: two additional apical spines, right and left (ar and al); two additional lateral ones (lr and ll) and two additional dorsal ones, right and left (dr and dl). Thus, the skeleton of this radiolaria have a total of eighteen spines, against five in D. gracilipes Bailey. All skeletal spines of the described radiolaria are thin and long. The basic spines are longer than the additional ones. The basic spines and the vertical spine begin in the centre of the skeleton. They all begin approximately in a singe point and are tightly connected to each other. These spines, which protrude the wall of the cephalis or thorax, point outwards. The additional spines are at the base, more connected to the surface of the skeleton, not with its centre. Apparently, during the development of the radiolaria, these spines are formed later than the min spines. The earlier in their growth stages, the nearer to the centre of the skeleton the roots of the spines are found. Two additional apical spines (ar and al) appear on the surface of the cephalis. They start rather near the centre of the skelton and are solidly bound to the surface of the cephalis by help of some supporting and arching bars (Fig. 5). They are somewhat shorter than the apical spine (A). The additional lateral spines (lr and ll) begin at the very transition between cephalis and thorax. By the help of some supporting arches, like small roots, these spines are connected to the skeleton. They are somewhat shorter than the primary lateral spines (Lr and Ll). On one of the additional lateral spines (ll) there were thin, flat, oblique protruding prosesses, as on the main spines of the skeleton. Between the two secondary lateral spines (lr and ll) and the dorsal soine (D) there is another couple of additional spines – they are additional dorsal spines (dr and dl). These spines were clearly a late developmental stage of the radiolarian skeleton. In the individual chose for drawing Fig. 6, they were formed at the latest ontogenetic step of the thorax. They are significantly shorter then the rest of the spines.
Compared with the skeleton of Dictyophimus gracilipes Bailey the one of Dictyophimus multispinus is thinner and more tender.The measurements of its cephalis are smaller. The following measurements of the various parts of Dictyophimus multispinus are given: Hight of cephalis 25 µm, width of cephalis 31-34 µm, height of the whole skeleton (cephalis and thorax) 57 µm, length of Lr from the edge of the thorax 66 µm, length of Lr from the centre 110 µm, length of ar 32 µm, length of dr 36 µm.
The type species of this radiolaria was found in a rather large quantity at station 4 (1930) in a sample taken at a depth of 200-100 m.
Station 4 (1930) is located 79°11’N, 71°39’E. At this staion, according to profiles of 1930, relatively shallow depths were found, -511 m. The salinities in the deeper layers were: 34.96 per mill at 500 m, 34.49 per mill at 50 m depth. At the bottom there were negative temperatures, -0.93°, at 300 m depth + 0.27° and maximum at a depth of 150 m + 1.18°. At shallower depths there were also negative temperatures, and the salinity constantly decreased. To judge from the hydrological profile, warm water came into this station from the northern side.
Probably, to this picture belongs also a radiolaria found by me in the 1929-material from station 17 in the profile from the southern point of Frantz Josef’s Land and eastwards in the Barents Sea. This radiolaria was found together with Dictyophimus gracilipes Bailey, but posessed a larger quantity of spines, long and thin. I had then only one individual, and I did not succeed in describing the structure of its skeleton.

Translation made by Gunnar Juve (29th January 2004).
Bernstein 1934











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