Elkinsia gen. nov., a Late Devonian Gymnosperm with Cupulate Ovules

The development of early terrestrial ecosystems

“…Gensel & Andrews, 1984). The first ovules are recorded from the United States and Belgium in the Famennian (Fa2c) (Fairon-Demaret & Scheckler, 1987;Rothwell, Scheckler & Gillespie, 1989). The elimination of the free-living gametophyte reduced dependence on environmental high humidity, while food reserves of seeds would have permitted germination and establishment under vegetation cover.…”

A Theoretical Scheme of the Large-Scale Evolution by Generating New Genes from Gene Duplication

“…The examples well investigated in paleontology are the divergence of Placodermi, cartilaginous fish and bony fish, the divergence of amphibians, reptiles and mammals, and the divergence of dinosaurs and birds, which occurred in the Chordata within the recent 4x10 8 years (Carroll, 1988). The seed plants also show the similar tendency in the successive divergence of Coniferophyta, Anthophyta and their relatives (Fairon-Demaret & Scheckler, 1987;Rothwell et al, 1989;Rowe, 1992;Stewart & Rothwell, 1993;Kawai & Otsuka, 2004), although many of these seed plants can also self-reproduce by the parthenogenesis and their explosive feature seems mild. Although the explosive divergence of body plans can be also explained by the biological activity expressed in terms of the interaction between differentiated cells (Otsuka, 2008), the present study derives this divergence from the aspect of the generation of new genes from gene duplication in diploid organisms.…”

Latisemenia longshania , gen. et sp. nov., a new Late Devonian seed plant from China

“…As in Latisemenia, Pseudosporogonites has broad integumentary lobes (although less fused), and cupules of both genera are broad but poorly developed (not overtopping the ovule); and cupules are lost in several groups of younger seed plants such as medullosans and callistophytes. A more entire integument of early ovules, such as large (long and wide) and/or extensively fused integumentary lobes as found in Dorinnotheca, Glamorgania and Pseudosporogonites, may have aided pollen capture and provided additional protection to the nucellus and water loss reduction [1,4,6,20,21,23]. Such functions of the integument appear evident in Latisemenia, with its flattened integumentary lobes that enclose the nucellus except for the apex.…”

“…While cupules of putative ovules of Cosmosperma have recently been reported from the Famennian of China [5], Latisemenia represents the first unequivocal Devonian ovules found outside Euramerica. Among the earliest seed plants from the Famennian, Latisemenia is the only one known to bear non-terminal ovulate cupules, whereas other Famennian cupules, if found attached, occur singly, in pairs, or in threes on the top of a fertile branch, which is sometimes dichotomous [1,3,4,[16][17][18][19][20][21][22][23] (table 1). Where known, these fertile branches are borne cruciately (Moresnetia and Elkinsia) or pinnately (Dorinnotheca) [19][20][21].…”