Botryococcus Kützing, 1849

Atfy, Haytham El, Abeed, Qusay & Uhl, Dieter, 2023, Non-pollen palynomorph and palynofacies assemblages from the Lower Cretaceous of Iraq: A glimpse into palaeobiology and palaeoenvironment, Geodiversitas 45 (11), pp. 353-366 : 356

Botryococcus Kützing, 1849 .

Botryococcus spp. colonies present in the samples are of variable size, ranging from 100 to 150 µm, and appear as moderately degraded botryoidal colonies that lack clear cup shapes, and are highly fluorescent ( Fig. 3 A-C). They are proportionally more abundant in samples 09-243 and 09-262, less proportionally abundant in sample 09-234, and are absent in samples 09-242 and 09-255 ( Fig. 2 ).

Botryococcus colonies of the planktonic green algal genus are well-known as fossils, extending back to the Precambrian ( Batten & Grenfell 1996). Botryococcus is most often found in freshwater bogs, temporary ponds, pools, and lakes, however, considerable abundances are known to occur in variable saline/brackish water supporting its cosmopolitan habitat ( Batten & Grenfell 1996; Senousy et al. 2004; Kumar et al. 2017 and references therein).

Although Botryococcus coenobia have little biostratigraphic value, the fossil forms can be used, through analogy with the living microalga, to elucidate palaeoecological and climatic conditions and palaeoenvironmental reconstructions (e.g. Guy-Ohlson & Lindström 1994). In addition, they generate liquid hydrocarbons ( Batten & Grenfell 1996).

Figures

FIG. 3. — The palynological assemblage of the Yamama Formation: A, colony of degraded Botryococcus Kützing, 1849 seen in transmitted white light. Note characteristic globular outline and lustrous yellow colour;09-262-2_P47;B, isolated coenobium of degraded Botryococcus colony seen in transmitted white light; 09-234-1_P35; C, colony of Botryococcus fluorescing under incident blue light illumination, the globular outline of the cells is very clear however, the cell cups are not clearly visible; 09-234_P35; D, Palambages sp., 09-242-3_P36; E, Palambages sp., 09-262-2_W40, arrow refers to loophole (= Schlüpfloch of Gocht & Wille 1972); F, Palambages sp., 09-262-3_G36, arrow refers to loophole (= Schlüpfloch of Gocht & Wille 1972); G, Palambages sp., 09-262-3_G40, arrows refer to loophole (= Schlüpfloch of Gocht & Wille 1972); H, marine prasinophyte phycoma of the genus Pterospermella Eisenack, 1972, 09-262-1_H53; I, dinocyst Batioladinium micropodum (Eisenack & Cookson, 1960) Brideaux, 1975, 09-234-1_R56; J, dinocyst, 09-234-1_M50; K, dinocyst, Cribroperidinium sp., 09-234- 1_N53; L, Leiosphaeridia sp., 09-255-3_G53; M, Leiosphaeridia sp., 09-262-3_T37; N, Leiosphaeridia sp., 09-234-3_S51; O, Leiosphaeridia sp., 09-255, arrow points to a possible encystment opening. Scale bars: 20 μm.

FIG. 2. — Quantitative representation of the percentages for the recorded NPPs in the studied samples: A, 09-234; B, 09-242; C, 09-243; D, 09-255; E, 09-262.