Lamprothamnium, Groves, 1916

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 : 396-398

Lamprothamnium sp.

( Fig. 6 I-L)

DESCRIPTION

Medium-sized gyrogonites, 432-648 µm high (mean 547 µm) and 297-513 µm wide (mean 434 µm), elongate, prolate to sub-cylindrical in shape, with an isopolarity index ranging from 111-163 (mean

127). Apex lamprothamnoid, truncated, showing a marked periapical depression due to decreasing cell thickness. Ŋe base is rounded with a small basal pore (45 µm). Spiral cells flat to convex, without ornamentation. Eight to ten (frequently nine) convolutions are visible in lateral view.

TABLE 3. — Charophyte species and gyrogonite abundances of samples studied from the eastern margin of the Ebro Basin (sections of Santpedor, Maians & Rubió). Vertical position of samples does not represent their relative stratigraphic position. Abbreviations:, 1-25; ·, 26-100; l,>100.

REMARKS

A population from Sant Bartomeu del Grau (NE Ebro Basin) belongs to the genus Lamprothamnium according to the general sub-cylindrical shape and the apical structure ( Table 2 ). Gyrogonites of Lamprothamnium sp. from sample CC-1 is similar in gyrogonite width and convolution number to the Lower Eocene Lamprothamnium priscum Castel & Grambast, 1969 . However, gyrogonites from the Ebro Basin are about 115 µm shorter, resulting in a more rounded morphology.Poor preservation hinders their specific attribution.

Figures

FIG. 6. — Charophytes from Sant Boi, Artés and lateral south-western Formations,Ebro Basin:A-D, Chara microcera Grambast & Paul, 1965, El Talladell outcrop; A, apical view, no. 80075 MGSCB, sample BO-2; B, lateral view, no. 80076 MGSCB, sample BO-2; C, lateral view, no. 80077 MGSCB, sample BO-2; D, basal view, no. 80078 MGSCB, sample BO-2; E-H, Psilochara aff. acuta Grambast & Paul, 1965, Sarral section; E,apical view, no. 80079 MGSCB,sample SA-2;F, lateral view, no. 80080 MGSCB,sample SA-2;G, lateral view, no. 80081 MGSCB, sample SA-2; H, basal view, no. 80082 MGSCB, sample SA-2; I-L, Lamprothamnium sp. El Perers-Serrat Rodó section (Cal Carreter locality); I, apical view, no. 80083 MGSCB, sample CC-1; J, lateral view, no. 80083 MGSCB, sample CC-1; K, lateral view, no. 80084 MGSCB, sample CC-1; L, basal view, no. 80085 MGSCB, sample CC-1. Scale bar: 500 µm.