Nodosochara jorbae Choi, 1989

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 : 401

Nodosochara jorbae Choi, 1989

( Fig. 7 D-F)

Nodosochara jorbae Choi, 1989: 33-36 , pl. 6, fig. 1-9, pl. 15, fig. 3.

DISTRIBUTION. — Formerly, N. jorbae was thought to be exclusive to the Upper Priabonian to Lower Rupelian of the Ebro Basin ( Stephanochara vectensis local biozone of Feist et al., 1994). However, Sanjuan et al. (2012) recently showed that this species already occurred in the middle part of the Priabonian ( Harrisichara vasiformis-tuberculata biozone). In the present study, N. jorbae is reported abundantly in Sant Boi de Lluçanès, Sobremunt, Sant Bartomeu del Grau, Oristà, Santa Maria d’Oló and Torre Casanova near Moià ( Table 2 ). Nodosochara aff. jorbae has also been reported by Mebrouk et al. (1997) in the Middle Eocene from the north-eastern Sahara ( Algeria).

DESCRIPTION

Gyrogonites large, 660-912 µm high (mean 758 µm), and 540-860 µm wide (mean 680 µm), inversely pear-shaped but sometimes sub-spherical or ellipsoidal, with an isopolarity index ranging from 90-140 (mean 112). Spiral cells 86 µm wide, convex and smooth. Eight to ten convolutions, more often nine, are visible laterally. Apex nitellopsidoid, slightly convex or sub-rounded, with a well-marked thinning and narrowing of the spiral cells in the periapical zone. Periapical depression frequently well-defined. Apical nodules are distinct, more or less prominent, and clustered in an apical rosette. Base rounded or conical. Basal pore superficial and small, without a basal funnel.

REMARKS

N. jorbae shows similarities with Nodosochara thevallensis Riveline, 1986 from the Upper Eocene of the French Brittany although gyrogonites from the single known population of N. thevallensis are about 300 µm larger and 230 µm wider, have more convolutions and the apex is in general less prominent than the type of N. jorbae . Other Nodosochara species are ornamented.

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.