Parvicingula alata Kozlova and Vishnevskaya, 2012

Vishnevskaya, Valentina S. & Kozlova, Genrietta E., 2012, Volgian and Santonian-Campanian radiolarian events of the Russian Arctic and Pacific Rim, Acta Palaeontologica Polonica 57 (4), pp. 773-790 : 786-787

Parvicingula alata Kozlova and Vishnevskaya sp. nov.

Figs. 4T , 6F, G .

1994 Parvicingula sp. F ; Kozlova 1994b: pl. 8:1–3, 6.

Etymology: In allusion to the wings.

Type material: Holotype N G−1−2K (see Fig. 6F ), Paratype N667/68; both at the Museum of the Microfaunal Laboratory VNIGRI, St Petersburg .

Type locality: Gorodishce section, Uljanovsk, Volga Basin, Russia .

Type horizon: Upper Volgian .

Diagnosis.—Typical Parvicingula with dome shaped cephalothorax, bearing 3 short massive spines.

Description.—Test conical with nine (or more?) post−abdominal segments. Cephalis and thorax together dome shaped, irregularly perforated, with coarse to thorny surface. Apical horn massive, very short subconically, with apical pore; spines 2, L and D short, situated at centre of cephalo−thorax. Distinct complete circumferential ridge beginning at the base of the first post−abdominal segments. Thorax and following segments approximately equal in height, with three rows of uniform hexagonal pore frames; pores circular.

Measurements (in µm).—Total height 130–165, height of cephalis + thorax 35–42, height abdomen and following segments 23–27, test width (maximum) 65–75, cephalis width 40–57.

Remarks.—The new species differs from congeners in having external spines and a dome−shaped cephalo−thorax.

Geographic and stratigraphic range.—Upper Volgian; Volga Basin, Russia.

Figures

Fig. 4. Scanning electron micrographs of Late Jurassic radiolarians from siliceous clay rocks in northern Russia, Barents offshore. Sample 234, Middle Volgian (Dorsoplanites panderi Ammonite Zone) of the Pesha River Basin, borehole 234 (A–C, E–G, I–T). Sample G2, Late Volgian (Craspedites subditus Ammonite Zone) of the Uljanovsk Volga Basin, species from siliceous clay rocks in northern Russia, section Gorogische (D, H). A. Pentalastrum sp., GIN N 234−R−15. B. Praeconocaryomma hexagona (Rüst, 1898), GIN N 234−R10. C. Stylartus sp., GIN N 234−R12. D. Stichocapsa devorata arctica Vishnevskaya and Murchey, 2002, GIN N G−2−R1−3. E, F. Hagiastridae. E. GIN N 234−R11a. F. GIN N 234−R11b. G. Orbiculiforma? retuza (Kozlova, 1971), GIN N 234−R13. H. Spinicingula ceratina Kozlova and Vishnevskaya sp. nov., GIN N G−2−R1−5b. I. Praeparvicingula aff. sencilla Hull, 1995, GIN N 234−R21. J, M. Parvicingula cf. jonesi Pessagno, 1977. J. GIN N 234−R18b. M. GIN N 234−R18c. K. Parvicingula jonesi Pessagno, 1977, GIN N 234−R18a. L. Parvicingula blowi Pessagno, 1977, GIN N 234−R16. N. Parvicingula cf. grantensis Pessagno and Whalen, 1982, GIN N 234−R19b. O. Praeparvicingula holdsworthi (Yang, 1993), GIN N 234−R17. P. Parvicingula cf. obstinata Hull, 1995, GIN N 234−R23b. Q. Stichocapsa sp., GIN N 234−R27. R. Parvicingula rothwelli Pessago, 1977, GIN N 234−R24. S. Praeparvicingula rotunda Hull, 1995, GIN N 234−R25. T. Parvicingula alata Kozlova and Vishnevskaya sp. nov., GIN N 234−R1−2.

Fig. 6. Scanning electron photomicrographs of Late Jurassic radiolarians from siliceous clay rocks in northern Russia, Barents Sea region. A–F from Kozlova (1994b). A. Quasicrolanium planocephala (Kozlova, 1976), uppermost Volgian, Kolguev offshore, borehole 140, sample 140, VNIGRI N 140−667/41a. B–E. Spinicingula ceratina Kozlova and Vishnevskaya sp. nov. B, C. From Narjan−Mar, borehole 5, Upper Volgian, sample 5. B. Holotype, VNIGRI N 667/66. C. VNIGRI N 667/66−1. D, E. From Upper Volgian, Gorodishce section (Craspedites subditus ammonite Zone) of Uljanovsk Volga Basin, sample G2. D. GIN N G−R1−1. E. GIN N G−R1−2. F, G. Parvicingula alata Kozlova and Vishnevskaya sp. nov., Middle Volgian, Gorodishce section (Dorsoplanites panderi Ammonite Zone) of Uljanovsk Volga Basin, sample G1. F. Holotype, GIN N G−1−2Ka. G. GIN N G−1−3K. H. Parvicingula papulata Kozlova and Vishnevskaya sp. nov., holotype, GIN N P−1K. Pechora Basin, Ukhta section, sample P, Lower Kimmeridgian. Scale bars 50 µm.