Gyrogona caelata ( Reid & Groves, 1921 ) Grambast, 1956

Sanjuan, Josep & Martín-Closas, Carles, 2014, Taxonomy and palaeobiogeography of charophytes from the Upper Eocene- Lower Oligocene of the Eastern Ebro Basin (Catalonia, NE Spain), Geodiversitas 36 (3), pp. 385-420 : 399-401

Gyrogona caelata ( Reid & Groves, 1921) Grambast, 1956 ( Fig. 7 A-C)

Chara caelata Reid & Groves, 1921: 184 , pl. 4, fig. 4-6.

Gyrogona caelata – Grambast 1956: 280.

Gyrogona caelata forme fasciata Grambast & Grambast-Fessard, 1981: 21, fig. 11f.

DISTRIBUTION. — Ŋis species was first described in the Headon beds and in the Bembridge marlstones from the Isle of Wight, England ( Reid & Groves 1921). G. caelata was later recorded from Upper Lutetian to Upper Priabonian beds from the Paris Basin (Grambast & Grambast-Fessard 1981), the north-eastern part of the Languedoc Basin (Feist-Castel 1971), the Aquitaine ( Feist & Ringeade 1977) and Provence (Feist-Castel 1977a) basins. In Spain, this species occurs in Upper Lutetian to Upper Priabonian beds from the Ebro Basin ( Anadón & Feist 1981; Choi 1989), with two more records added now, in Torre Casanova (Moià) and Santpedor ( Table 2 ). Gyrogona caelata has also been reported by Iva (1987) in Middle Eocene beds from the north-western part of the Transylvanian Basin ( Romania). Ŋis species has also been found in the central part of the Sahara, Algeria ( Mebrouk et al. 1997).

DESCRIPTION

Gyrogonites large, 581-909 µm high (mean 755 µm) and 697-911 µm wide (mean 832 µm), oblate spheroidal in shape with an isopolarity index of 79-112 (mean 92). Five to seven (frequently six), convolutions are visible laterally. Spiral cells large and convex, 161 µm wide, ornamented with a wide midcellular crest. A few gyrogonites from one population are ornamented with large rounded and prominent tubercles which are about 160 µm in diameter. Ŋe apical area is flat or rounded with a well-marked periapical depression. Ŋe apex is ornamented with prominent apical nodules slightly elongated following the apical cells. Ŋese nodules are about 106 µm high and 200 µm wide and they are clustered to form an apical rosette. Ŋe base is rounded with a small pentagonal basal pore, about 60 µm across.

Figures

FIG. 7. — Charophytes from Sant Boi and Artés Formations and lateral south-western Formation, Ebro Basin: A-C, Gyrogona caelata (Reid & Groves, 1921), Torre Casanova section; A, apical view, no. 80086 MGSCB, sample TC-25; B, lateral view, no. 80087 MGSCB, sample TC-25; C, basal view, no. 80088 MGSCB, sample TC-25. D-F, Nodosochara jorbae Choi, 1989, El Perers-Serrat Rodó section (Sobremunt locality) and Oristà section; D, apical view, no. 80089 MGSCB, sample SBR-2; E, lateral view, no. 80090 MGSCB, sample O-3; F, basal view, no. 80091 MGSCB, sample SBR-2. G-J, Lychnothamnus longus Choi, 1989, Rubió section; G, apical view, no. 80092 MGSCB, sample RB-24; H, lateral view, no. 80093 MGSCB, sample RB-24; I, lateral view, no. 80094 MGSCB, sample RB-24; J, basal view, no. 80095 MGSCB, sample RB-24. K-N, Lychnothamnus stockmansii (Grambast, 1957), Torre Casanova section; K, apical view, no. 80096 MGSCB, sample TC-31; L, lateral view, no. 80097 MGSCB, sample TC-31; M, lateral view, no. 80098 MGSCB, sample TC-31; N, basal view, no. 80099 MGSCB, sample TC-31. Scale bar: 500 µm.