Archaeodictyomitra, Pessagno, 1976

Kochhann, Karlos G. D., Baecker-Fauth, Simone & Fauth, Gerson, 2013, Late Maastrichtian Radiolaria from ODP Leg 165 - Site 999 B, Colombian Basin, Geodiversitas 35 (1), pp. 5-20 : 9-10

Archaeodictyomitra ? sp. 2 ( Fig. 4D )

FIGURED SPECIMEN. — ULVG-7323.

MATERIAL. — 28 specimens (recovered with the hydrogen peroxide method); 28 specimens (recovered with the acetic acid method) .

DESCRIPTION

Test conical proximally and cylindrical distally; non-lobulated, with poor-developed strictures and costate throughout. Costae converging in the cephalic area. Cephalis probably imperforated and sharply pointed apically. One row of pores (probably relicts) between adjacent costae. Distal margin ragged, with poor-developed costal projections.

REMARKS

Although O’Dogherty (1994) suggested a broader definition of the genus Dictyomitra Zittel, 1876 , we follow Pessagno’s (1976) criteria and tentatively attribute this species to Archaeodictyomitra (i.e. nonlobulated outline and continuous costae). The poor preservation of all specimens does not enable the recognition of primary pores and prevents the specific identification of the specimens.

Figures

FIG. 4. — SEM images of Radiolaria recovered from the sample 999B/60/2W/70-74 cm: A, Archaeodictyomitra cf. A. squinaboli Pes- sagno,1976 (H2O2 method);B, Archaeodictyomitra cf. A. lamellicostata (Foreman, 1968) (H2O2 method); C, Archaeodictyomitra? sp. 1 (H2O2 method); D, Archaeodictyomitra? sp. 2 (H2O2 method); E, Dictyomitra sp. 1 (H2O2 method); F, Dictyomitra sp. 2 (H2O2 method); G, Mita regina? (Campbell & Clark, 1944) (CH3COOH method); H, Amphipyndax tylotus Foreman, 1978 (H2O2 method); I, Stichomitra asymbatos Foreman,1968 (H2O2 method);J, Stichomitra? sp.1 (H2O2 method); K, Stichomitra? sp. 2 (H2O2 method); L, Rhopalosyrin- gium magnificum Campbell & Clark,1944 (H2O2 method). The chemical compound after each species indicates the chemical method applied in the recovery of each figured specimen. Scale bars: 100 µm.