Gongylothorax verbeeki (Tan, 1927)

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 : 116

Gongylothorax verbeeki (Tan, 1927)

Figs. 9i, i 1 , i 2

1927 Dicolocapsa verbeeki Tan Sin Hok , p. 44, pl. 8, figs. 40, non 41.

non 1968 Gongylothorax verbeeki (Tan Sin Hok) – Foreman, p. 20, pl. 2, figs. 8a-c.

1994 Hiscocapsa verbeeki (Tan Sin Hok) – O’Dogherty, p. 199, pl. 31, figs. 1-6.

2009 Zhamoidellum ovum Dumitrică – Ishii et al., p. 348, pl. 21, fig. 12.

Studied material. One specimen in sample OZ824, stub PD120 - OZ824- R13-28 .

Dimensions. Length 123 µm, diameter of thorax 125 µm.

Remarks. The specimen from the S’Ozzastru section resembles very well the type specimen (lectotype, according to O’Dogherty, 1994). The Maastrichtian specimen illustrated by Foreman (1968) differs from the lectotype not only in age but also in shape. The lectotype is smaller, the apical part of thorax slightly conical and the pores are, on short portions, alighed in short rows, whereas the Californian specimen is “flat, centrally depressed”, and the frames of the pores are equal and show no lineation. However, Foreman, who had examined the topotypic material from Tan Sin Hok’s loc. 150, and remarked the presence of a tube on the thorax of this species (the sutural pore of Dumitrică 1970) wrote that it differs only slightly from the one present in the California form, fact that she did not consider it as representing sufficient evidence for separating these two forms into different species.

Occurrence. Lower Cretaceous of Tethys.

Figures

Fig. 9 a, b - Eucyrtidiellum sardoum Dumitrică n. sp.: a, a1 - holotype, OZ836; b - paratype, OZ839. c-e, g - Hemicryptocapsa capita Tan: c - OZ838, d - OZ824, e - OZ837, g - OZ839. f-f2 - Gongylothorax oculoporus Dumitrică n. sp.: OZ824 and OZ826. h – Gongylothorax (?) sp., OZ834. i-i2 – Gongylothorax verbeeki (Tan), OZ824; i1, i2 - details of apical and apertural parts. j, j1, j2 - Williriedellum buekkense (Kozur), OZ824: j – lateral view, j1 – apical view with sutural pore, jb – distal view. k – Arcanicapsa simplicissima Dumitrică n. sp., OZ836, k1 – distal view showing the apical rosette. l-o, t, t1, u - Kozurium hindei (Tan): l, l1 - OZ837, m - OZ839, n - OZ834, o - OZ836, t-t1 x300, OZ825, n1 – distal aperture of fig. 9n. p-s1 - Cryptamphorella alieviana Dumitrică n. sp.: p, s - OZ825, r - OZ837, s1 detail of test of fig. s. Figs. p-s x200; figs. c-e, g x250; figs. a, a1, b, f, f2, h, h1, i, k-o, t, t1, x300; i1, i2, m 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).

Fig. 2 Geological section across the S’Ozzastru area (trace A-A’ in the geological map of Fig. 1). Legend: a - Recent and present alluvial deposits (Holocene). b - Cuccuru ’e Flores Conglomerate: sandstone and breccia (middle Eocene). c - Siniscola Marl: marl (1) and marly limestone (2) (late Valanginian). d - Schiriddè Limestone: cherty limestone (early Valanginian). e - Monte Bardia Limestone: limestone (early Tithonian - late Berriasian). f - S’Adde Limestone: limestone and cherty limestone (latest Bathonian - earliest Tithonian). g - Dorgali Formation: dolostone (middle-late Bathonian). h - Metamorphic basement (Palaeozoic). i - Fault (modified from Bottini et al., 2018).