Lychnothamnus stockmansii ( Grambast, 1957 ) Soulié-Märsche, 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 : 402

Lychnothamnus stockmansii ( Grambast, 1957) Soulié-Märsche, 1989 ( Fig. 7 K-N)

Rhabdochara stockmansi Grambast, 1957: 355 , pl. 8, figs 10-14.

Lychnothamnus stockmansi – Soulié-Märsche 1989: 160.

DISTRIBUTION. — Lychnothamnus stockmansii has been recorded from numerous localities ranging in age from the Upper Eocene (Middle Priabonian) to the Lower Oligocene (Lower Rupelian) ( Table 5 ). In France, this species occurs in the Paris ( Riveline 1986), Aquitaine ( Feist & Ringeade 1977) and Provence ( Grambast 1957; Montenat 1968; Touraine 1971; Feist-Castel 1977a) basins. In England, this species has been reported in the Isle of Wight (Feist-Castel 1977b; Riveline 1986). Stockmans (1960) found this species at a number of Oligocene localities in Belgium. Lychnothamnus stockmansii also occurs in Oligocene beds in Germany ( Schwarz 1985). In Spain, this species has already been reported from the island of Mallorca (Martín-Closas & Ramos 2005) and in Upper Eocene beds of the Ebro Basin ( Choi 1989). In the present study, L. stockmansii was found in the Upper Priabonian-Lower Rupelian from the Torre Casanova (Moià), Moià, Santpedor, Rubió, Rocafort de Queralt and Sarral localities ( Table 2-4 ). Baciu & Feist (1999) reported it from the Lowermost Oligocene of the Transylvanian Basin ( Romania). Ŋe species is well-represented in many Chinese localities ( Table 5 ). Xinlun (1978) found it in Upper Eocene- Lower Oligocene beds in the Bohai coastal region (NE China). Liu & Wu (1990) and Lu & Luo (1990) reported L. stockmansii from the Tarim Basin in the provinces of Qinghai and Xinjiang (NW China). In southern China, this species was reported by Huang et al. (1988) in Guangdong province and by Liu (1989) in Yunnan province. Ŋis database suggests that Lychnothamnus stockmansii was an Eurasiatic species widely distributed from Western Europe to China.

DESCRIPTION

Gyrogonite large, 581-776 µm high (mean 659 µm), and 387-619 µm wide (mean 561 µm), variable in shape, generally ellipsoidal, with an isopolar- ity index ranging from 102-150 (mean 120). Ŋe apical zone shows a remarkable constant width of the spiral cells, which results in a flat apex. Some specimens show a small triangular-shaped tubercle, about 45 µm across, located at the junction of the spiral cells at the apex, which is reminiscent of the sylvula described by Soulié-Märsche (1989) in recent Lychnothamnus barbatus . Ŋe base is tapered with a star-shaped basal funnel, which is poorly developed in specimens with flat spiral cells. Basal pore about 95 µm in diameter. Six to nine, frequently eight, cells visible laterally. Ŋese are normally concave, non-ornamented and separated by prominent sutures which in some specimens are bicarinate.

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.