Crococapsa cf. horokanaiensis (Kawabata, 1988)

Dumitrica, Paulian, Dieni, Iginio & Massari, Francesco, 2022, Valanginian Radiolarians Of Ne Sardinia (Italy) In The Frame Of The Weissert Event, Acta Palaeontologica Romaniae 18 (2), pp. 97-159 : 130-131

Crococapsa cf. horokanaiensis (Kawabata, 1988)

Fig. 12b

1982 Sethocapsa (?) sp. – Matsuyama et al., p. 377. pl. 1, fig. 6.

1988 Sethocapsa horokanaiensis Kawabata , p. 4, pl. 1, fig. 10, non 9, 11, 12.

1997 Sethocapsa horokanaiensis Kawabata – Ishida & Hashimoto, pl. 3, fig. 9.

2009 Stichocaps a sp. B – Ishii et al., pl. 17, fig. 12.

Description. Shell narrow conical with 5 ocelli well visible in lateral view on half a perimeter. Cephalis practically imperforate with rounded apex and separated from thorax by a circumferential row of pores. Thorax and abdomen trapezoidal in lateral view with irregularly distributed very small pores. They increase in diameter distally, and those of thorax have protruding rims. Post abdominal segment hemispherical, a little higher than its ray and separated from abdomen by a circumferential row of

Text-fig. 2 Inner mould of a specimen of Crococapsa uterculus (Parona) from a Valanginian sample of the Batain Plain, Oman.

wide ocelli, five on half a perimeter. Pores of postabdominal segment circular, polygonally framed and larger than those of the abdomen.

Studied material. A single specimen in sample OZ834, coll. MGP-PD, stub PD120-OZ834-R10-14.

Dimensions. Length 137 µm, diameter of last segment 77 µm.

Remarks. The illustrated specimen differs from the holotype of Stichocapsa horokanaiensis by not having the pores of the thorax and abdomen polygonally framed. It differs from Crococapsa zweilii (Jud, 1994) , to which it seems also close, by being slimmer and also by having the postabdomen much smaller. Two specimens quite similar to the studied one were illustrated by Ishii et al. (2009) from north-western Pacific, and Ishida & Hashimoto ( 1997) from the East Shikoku, Japan. It can be inferred that this morphology could correspond to an independent species which, however, we do not dare to describe herein.

Occurrence. Upper Valanginian of Sardinia .

Figures

Fig. 12 b - Crococapsa cf. horokanaiensis (Kawabata), OZ834. a, c, d - Crococapsa zweilii (Jud): a, OZ826; c, OZ836; d, OZ825. e-h - Crococapsa uterculus (Parona): e, f, h - OZ834, g - OZ825. i-o - Ocellicapsa ruthae Dumitrică n. sp.: i - OZ837, j - OZ837, k - OZ836, i - OZ834, m - OZ824, n - OZ838, n1 - detail of cephalothoracic body, arrow shows the place of very small pores at the boundary between the two parts of cephalic cavity, o - OZ825. p, r, t, v - Squinabolum elegans Dumitrică n. sp.: p - OZ824, r - OZ826, t - OZ836, s - Amphipyndax zyabrevi Dumitrică n. sp. - OZ825. u - Campanomitra pulchella (Rüst), OZ836. v - OZ834. w, x - Archaeodictyomitra inflata Dumitrică n. sp.: w - OZ839, x - OZ834. Figs. a, c-h, u x250, all the others x300.