Exine ultrastructure in pollen grains of Classopollis Pflug from the Cretaceous of Lebanon

Artificial pollen walls simulated by the tandem processes of phase separation and self‐assemblyin vitro

“…in Classopolis sp. ; Zavialova et al, 2010). Lamellate structures are principally for spores and for endexines of many pollen walls.…”

Cheirolepidiaceous diversity: An anatomically preserved pollen cone from the Lower Jurassic of southern Victoria Land, Antarctica

“…Classopollis pollen is known from the Early Triassic through the Late Cretaceous and is numerous in deposits worldwide (Taylor et al, 2009;Zavialova et al, 2010a;2010b). Previous studies of palynofloras from Carapace Nunatak have been interpreted as late Middle Jurassic (Shang, 1997;Ribecai, 2007), which conflicts with Early Jurassic radiometric age constraints on the timing of lava emplacement (Elliot, 2013).…”

“…Infrastructure, supratectal ornamentation, and striations have recently been used in Argentina to assign taxonomic value to Classopollis sporae dispersae discussed by Reyre (1970) and to introduce new species (Villar de Seoane, 2014), and the differentiation of infrastructure among species of Classopollis has been discussed by Zavialova et al (2010aZavialova et al ( , 2010b. One concern about taxonomic placement into dispersed species based on these pollen characters is that they may represent different stages in pollen development, but the pollen characters of Classostrobus comptonensis discussed by Taylor and Alvin (1984) were based on samples from interpreted mature and immature cones, which helped to clarify differences between developmental morphologies of the pollen wall.…”

Frenelopsis antunesii sp. nov., a new cheirolepidiaceous conifer from the Lower Cretaceous of Figueira da Foz Formation in western Portugal

“…They are represented in the macrofossil record by numerous species based on vegetative shoots, along with associated pollen and seed cones. The Cheirolepidiaceae were initially recognized as a distinct family, based on their distinctive spherical pollen grains with a ring-like germinal groove and striate equatorial band of the Classopollis type, notable for its complex ultrastructure (Pettitt and Chaloner, 1964;Barnard, 1968;Vakhrameev, 1970;Doludenko, 1978;Pons, 1979;Taylor and Alvin, 1984;Watson, 1988;Zavialova, 2003). In the Northern Hemisphere, the family disappeared at the end of the Cretaceous, but persisted into the Early Paleogene in central Patagonia (Barreda et al, 2012).…”