Homunculodiscus cauleti, Dumitrica, 2019

Dumitrica, Paulian, 2019, Cenozoic Spumellarian Radiolaria With Eccentric Microsphere, Acta Palaeontologica Romaniae 15 (1), pp. 39-60 : 41

Homunculodiscus cauleti nov. sp.

Figure 2 a-h

Description. Shell disc-shaped, very thin, consisting of two parallel porous plates interconnected by short transversal bars that, in transmitted light look like black spots. They are either irregularly arranged or, most of them are aligned to form arches or incomplete ellipses around the diploconchal structure. Microsphere small, spherical. Deuteroconcha antapically disposed, usually crescent-shaped. Usually there is another crescent-shaped chamber beyond it. The latter is usually part of an elliptical circle surrounding the diploconchal structure. Pores circular, densely arranged in circular or radial rows, the latter especially toward periphery. These rows may be separated by radial beams prolonged into thin short peripheral spines. Periphery irregular, frayed as if not finished.

Material. Eight specimens, of which four illustrated, in the upper lower Paleocene .

Holotype. Figures 2b, 2f , coll. MGL 103555 .

Dimensions. Diameter of microsphere 14 μm, of shell 185-224 μm.

Etymology. The species is named for Dr. Jean-Pierre Caulet who described for the first time the species that will become the type species of the genus.

Remarks. This species seems to be intermediate between Homunculodiscus nascens and H. tainemplecta (Caulet) . It has better marked crescent-shaped deuteroconcha and elliptical circles around it than Homunculodiscus nascens nov. sp.

Range and occurrence. Recorded only in the upper lower Paleocene sample DSDP 21-208-30 CC, north Lord Hove Rise, southwestern Pacific.

Figures

Fig. 2 a-h. Homunculodiscus cauleti nov. gen., nov. sp., DSDP 21-208-30CC; scale bars of figs. a-d = 50 μm, of figs. e-h same bars = 25 μm. e represents the central part of a; f represents the central part of b; g represents the central part of c; h represents the central part of d.