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Dipylissa bensoni Dumitrica, 1988

Description - Add description

Benson, 1966, p. 268-269; pl. 18, figs. 9-10:

Spirema sp.

Test an involute spiral with three recognizable chambers, the last two chambers being bulbous or spherical as in a globigerinid foraminifer. First chamber a small, latticed, spherical shell with 2-3 equal, polygonal pores on its half circumference. Second spherical chamber arises from inner shell and completely envelops this shell and closes upon itself. Third chamber larger than second, spherical, completely covers the proximal portion of the whorl of the second chamber. No large opening in third chamber visible. Most tests oriented so that edge views of the test are observed; in this position the outline of the test is similar to a figure 8 but with one chamber smaller than the other. Numerous thin, cylindrical radial beams arise from the surface of the first chamber and join with the inner surfaces of the second and third chambers. Pores of the two outer chambers equal in size, polygonal to subpolygonal, hexagonally arranged, with rudimentary polygonal frames, approximately 10-12 pores on half the circumference of the third (largest) chamber. Surface of test with thorns or short, thin, conical spines arising from the nodes of the intervening bars. In one test an outer, thin-walled, small-pored, smooth ellipsoidal mantle, supported by the surface spines, partially envelops the test.

Measurements; based on 4 specimens from station 27: length of test (edge view of spiral) 75-91 µm; diameter of first chamber 12-15 µm of second chamber 47-54 µm, of third chamber 53-62 µm.

Remarks. The resemblance of this species to some globigerinid foraminifers is remarkable; however, there is no doubt that this species is a radiolarian. Reference to this species in the literature could not be found; therefore, it is a new species. Because of its rare occurrence in the Gulf its complete range of variation could not be investigated. For this reason a new name is not proposed for this taxon.

Distribution. This species occurs rarely in the Gulf at stations 27, 34, 46, 56, 60, 64, 93, and 99 in the southern half of the Gulf and at stations 106 and 151 in the northern half. It is, therefore, an oceanic species with little affinity for Gulf waters.
Benson 1966











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