Halimeda? sp, Lamouroux, 1812

SCHLAGINTWEIT, FELIX, RASHIDI, KOOROSH & MOSAVINIA, ABDOLMAJID, 2021, First Record Of Calcareous Green Algae (Dasycladales, Halimedaceae) From The Paleocene Chehel Kaman Formation Of North-Eastern Iran (Kopet-Dagh Basin), Acta Palaeontologica Romaniae 17 (1), pp. 51-64 : 58

Halimeda? sp .

Fig. 9

Remarks: In our thin sections we observed one specimen showing a lateral protuberance (swelling) indicating a possible branching ( Fig. 9f ). Accepting the reconstruction of Boueina as provided by De Castro et al. (2008, fig. 1a; see also Bucur et al., 2018, pl. 6b), the Paleocene form ascribed to Halimeda nana Pia in Pia et al., 1932 by Segonzac et al. (1986, pl. 1, fig. 7) showing solid (= calcified, without uncalcified internodes) branching should be ascribed to Boueina Toula (see additional remarks by Granier and Bucur, 2017, p. 255 and Dragastan and Herbig, 2007). Being aware of the segment (node) variability (morphology and size) within a single species, we hesitate to ascribe the Iranian forms displaying three (four?) utricle layers in the cortical zone to any of the numerous established species (e.g., Dragastan and Herbig, 2007). Instead it is treated in open nomenclature expressing also doubts on the generic identity.

Dimensions: greatest observed length of cylindrical segments = 3.5 mm, diameter of segments = 0.48-0.85 mm, diameter of medullary filaments = 0.045 -0.063 mm, diameter of cortical filaments = 0.025 -0.042 mm.

Figures

Fig. 9 Halimeda? sp. from Paleocene carbonates of the Chehel Kaman Formation, northeastern Iran. a, longitudinal oblique section. b, transverse section with medullar zone occupying about the half of the total diameter. c, tangential section showing cortical filaments. d, longitudinal section. e, oblique transverse section. f, specimen exhibiting a protuberance/swelling/ or branching. Thin-sections: NF 12-2 (a), NF 12-3 (b-c), Nf 12-4 (d, f), Nf 12-1 (e).