Hiscocapsa rugosacutis Dumitrică, 2022

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 : 127

Hiscocapsa rugosacutis Dumitrică n. sp.

Figs. 11 f, f 1, h, h1

Description. Shell conical, tetracyrtid with last chamber large, spherical with wrinkled surface and open distally. Cephalis poreless, subspherical with a very thin and short apical spine. Collar boundary marked by the appearance of thoracic pores. Thorax and abdomen forming together with cephalis the conical proximal part of the skeleton, difficult to separate from each other. Their wall has small circular pores arranged in more or less circular rows. Postabdominal chamber very large, subspherical with small circular and dense pores arranged in groups of short rows of different orientations. Surface wrinkled, here and there with small nodules interconnected by thin ribs with different directions. Base of postabdomen slightly flattened with narrow funnel shaped circular aperture ( Fig.11 fa) or a larger aperture with protruding rim.

Studied material. Two specimens in the sample OZ826.

Holotype. Figs. 11h, h 1 , OZ826, coll. MGP-PD, stub PD120 -OZ826- R11-02 and 02a.

Paratype. Figs. 11f, f 1 , OZ826, coll. MGP-PD, stub PD120 -OZ826- R11-19 and 19a .

Dimensions. Length 145-175 µm, diameter of last chamber 113-125 µm.

Etymology. From the Latin rugosus, - a, - um, wrinkled and cutis – crust, bark.

Remarks. The two specimens resemble generally to one another by having a rather similar ornamentation of the postabdominal segment, but differ by having a different distal aperture and arrangement of pores and wrinkles.

Occurrence. Rare in the upper Valanginian of S’Ozzastru section.

Figures

Fig. 11 a-b1 - Hiscocapsa grutterinki (Tan): a, OZ834, b, OZ839. c, c1, d, g - Hiscocapsa (?) ventriosa Dumitrică n. sp.: b, OZ839, c, OZ836, c1, aperture, g - complete specimen, V40, Svinița, Romania. e - Doliocapsa utoi Dumitrică n. sp., OZ824. f, f1, h, h1 - Hiscocapsa rugosacutis Dumitrică n. sp., OZ826. i-i1 - Hiscocapsa aitai Dumitrică n. sp., OZ824. p, s -Hiscocapsa lagunculoides Dumitrică n. sp., OZ834, OZ838; p1, s1- distal apertures of both specimens. j - Squinabollum cf. elegans Dumitrică n. sp., OZ826. k, k1 - Doliocapsa weisserti Dumitrică n. sp., OZ834. l - Hiscocapsa tuberculata Dumitrică n. sp., OZ826. m, m1, n - Doliocapsa erbae Dumitrică n. sp., OZ834. o – Doliocapsa favopora Dumitrică n. sp., OZ834. r - Doliocapsa mediterranea Dumitrică n. sp., OZ834. Figs. a-d, j x250; figs. c1, e, e1, f, f1, g, h, i, i1, k, k1, l, p, r x300, m-o, p1 x400.

Fig. 1 Geologic map of the Siniscola area, NE Sardinia (from Dieni & Massari, 1971, updated in 1986). Legend: a - Recent and present alluvial deposits (Holocene). b - Scree deposits (Würm-Holocene). c - Detrital cones mostly composed of gelifraction limestone clasts (“éboulis ordonnés”) (Würm-Holocene). d - Uncemented alluvial cones mostly consisting of limestone clasts (Würm-Holocene). e - Terraced alluvial deposits composed of clasts of basement rocks (Riss?). f - Tightly cemented and dismembered alluvial cones mostly made up of gelifraction limestone clasts (Riss?). g - Cuccuru ’e Flores Conglomerate: polymict, chaotic and thick-bedded breccia and stratified sandstone (middle Eocene). h - Siniscola Marl: grey and grey-yellow marl and, in the upper part, alternating marl/marly limestone with ammonites and very abundant radiolarians and sponge spicules (late Valanginian). i - Schiriddè Limestone: light-brown cherty limestone and limestone with marly interbeds, containing ammonites, radiolarians, sponge spicules and calpionellids (early Valanginian). j - Monte Bardia Limestone: thick-bedded to massive white limestone in places bioconstructed, with corals, nerineids, etc. (early Tithonian - late Berriasian). k - S’Adde Limestone: light-brown to grey fine-grained, well-bedded limestone, condensed with hardgrounds near the base, cherty in the upper part, with ammonites and belemnites in the uppermost part (latest Bathonian - earliest Tithonian). l - Dorgali Formation: well bedded quartz-arenitic and locally ooidal brown dolostone (middle-late Bathonian). m - Crystalline basement (phyllite, micaschist, paragneiss, quartzite, etc.) (Palaeozoic). n - Fault. o - Attitude of beds and schistosity planes. p - Limits of slumped masses of Jurassic formations (Quaternary). q - Concave-upward slip surfaces delimiting rotational slumps (Quaternary). r - Edge of fluvial terrace. s - Quarry. A-A’ Trace of the geological section of Fig. 2. (extracted from Bottini et al., 2018).