Monocolpopollenites aff. texensis Nichols et al., 1973

Ramírez-Arriaga, Elia, Prámparo, Mercedes B. & Martínez-Hernández, Enrique, 2014, Angiosperm pollen grains from the Cuayuca Formation (Late Eocene to Early Oligocene), Puebla, Mexico, Palaeontologia Electronica 102 (8), pp. 1-38 : 9

Monocolpopollenites aff. texensis Nichols et al., 1973

Figure 4.7

Material. Sample Pb-8872, Palynology Laboratory, IGLUNAM.

Description. Monad pollen, heteropolar, bilateral symmetry, amb oval. Monosulcate. Exine tectate, the structure of the wall is difficult to discern, 0.8 µm thick, psilate.

Dimensions. Length 32 µm, width 22.4 µm, one specimen measured.

Remarks. In a monographic discussion concerning monosulcate genera, Nichols et al. (1973) proposed that the shape of the sulcus differentiates the genus Monocolpopollenites from Arecipites . Arecipites includes monosulcate grains with a tapered sulcus, not expanded or gaping at the ends. Monocolpopollenites includes grains with flared or round-ended sulcus.

Comparison. M. aff. texensis (in this contribution) has the sulcus extending the entire long axis of the grain, with margins tending to overlap centrally, as in M. texensis . However, the Mexican specimen is larger (32 µm) than M. texensis ( Nichols et al. 1973: 17–19 x 24–28 µm) and presents a psilate instead of scabrate exine.

Other occurrences. There are no previous records of this taxon in Mexico. The genus has been reported from the US Gulf Coast ( Frederiksen, 1980a) and in England ( Wilkinson and Boulter, 1980).

Figures

FIGURE 4. Angiosperm pollen grains from the Cuayuca Formation. 1, Corsinipollenites sp. 1, Pb–9334(1): EF G33/ 3; 2, Corsinipollenites sp. 3, Pb–9334(4): EF R36/1; 3, Corsinipollenites sp. 2, Pb–9334(4): EF T35/3; 4-5, Margocolporites sp., Pb–9340(1): EF N35/3; 6, Margocolporites aff. vanwijhei, Pb-9334(1'): EF T39/2; 7, Monocolpopollenites aff. texensis Nichols, Ames and Traverse 1973 Pb–8872(1A): EF W29/1; 8-9 Rhoipites sp., Pb–8890(1):101.9/17.2; 10, Lymingtonia sp., Pb–9334(4): EF S32/4; 11, Momipites tenuipolus Pb-9334(4): 101.6/12.5; 12, Momipites coryloides, Pb-9138’(1): 92.2/2.8; 13, Fabaceae pollen type 3, Pb–9334(4): EF M34/4; 14, Clavainaperturites sp., Pb– 9147(2): EF R34/2; 15, Linum pollen type, Pb–9334 (1’): EF S33/2; 16, Magnaperiporites sp., Pb–9334(4): EF R39/2; 9. Scale bar represnts 10 µm.