Lychnothamnus longus 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 : 401-402

Lychnothamnus longus Choi, 1989

( Fig. 7 G-J)

Lychnothamnus longus Choi, 1989: 7-10 , pl. 5, figs 1-12.

DISTRIBUTION. — Up to now, L. longus has only been found in the Late Priabonian-Earliest Rupelian of the eastern part of the Ebro Basin ( Choi 1989; Sanjuan & Martín-Closas 2012; Sanjuan et al. 2012). In the present study, this species was found in the Oristà, Santa Maria d’Oló, Torre Casanova (Moià), Moià, Santpedor and Rubió localities ( Tables 2 , 3).

DESCRIPTION

Gyrogonites are medium in size, 450-724 µm high (mean 618 µm), and 380-580 µm in width (mean 464 µm).Ŋey are ellipsoidal to ovoidal in shape with an isopolarity index of 104-180 (mean 130). Ŋe apex is rounded to truncate, in some cases pointed in the centre, and displays a marked apical thinning. Ŋe base shows variable morphology, in some cases elongated to form a broad column, and the basal pore shows a small star-shaped funnel. Ŋe spiral cells, flat to concave, are devoid of ornamentation and separated by prominent sutures, which in some specimens are bicarinate. Seven to ten (frequently eight) convolutions are visible laterally.

REMARKS

Lychnothamnus longus is very variable in size, shape and calcification. Many populations show a continuous change from small, cylindrical gyrogonites with concave spiral cells to large broadly rounded specimens with flat spiral cells.

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.