Fossil record of Ephedra in the Lower Cretaceous (Aptian), Argentina

Abstract

Fossil plants from the Lower Cretaceous (upper Aptian) of the La Cantera Formation, Argentina, are described. The fossils studied represent a leafy shooting system with several orders of articulated and striated axes and attached leaves with unequivocal ephedroid affinity. We also found associated remains of ovulate cones with four whorls of sterile bracts, which contain two female reproductive units (FRU). Ovulate cone characters fit well within the genus Ephedra. Special characters in the ovulate cones including an outer seed envelope with two types of trichomes, allowed us to consider our remains as a new Ephedra species. Abundant dispersed ephedroid pollen obtained from the macrofossil-bearing strata also confirms the abundance of Ephedraceae in the basin. The co-occurrence of abundant fossil of Ephedra (adapted to dry habitats) associated with thermophilic cheirolepideacean conifer pollen (Classopollis) in the unit would suggest marked seasonality at the locality during the Early Cretaceous. Furthermore, the floristic association is linked to dry sensitive rocks in the entire section. The macro- and microflora from San Luis Basin are similar in composition to several Early Cretaceous floras from the Northern Gondwana floristic province, but it may represent one of the southernmost records of an arid biome in South America.

Phylogenomics resolves the deep phylogeny of seed plants and indicates partial convergent or homoplastic evolution between Gnetales and angiosperms

“…Actually, the earliest fossil records of Gnetales and angiosperms can be dated back to the same geological periods (i.e. the Late Jurassic or Early Cretaceous [49,50]), although our divergence time estimates are largely consistent with previous studies (e.g. [51]), suggesting earlier origins of the two groups (figure 3).…”

A Review on Worldwide Ephedra History and Story: From Fossils to Natural Products Mass Spectroscopy Characterization and Biopharmacotherapy Potential

“…Containing approximately fifty species, the genus Ephedra (Family Ephedraceae) was distributed in arid and semiarid regions of Asia, Europe, northern Africa, southwestern North America, and South America [56][57][58][59][60]. In fact, Ephedra was distributed from the northern temperate zone (from the Canary Islands through the Mediterranean region and Central Asia to Shandong in China) to the arid regions of USA and Mexico, and to alpine area of the Andes in South America [26,27,[61][62][63][64].…”

A new macrofossil ephedroid plant with unusual bract morphology from the Lower Cretaceous Jiufotang Formation of northeastern China

“…Holotype − PE2018013101 ( Fig. 1 [25,26,30,35,38,39,41,46,47,53]. The richest diversity is in the Yixian Formation [16].…”

“…Jianchangia is similar to Gurvanella Krassilov [41], Beipiaoa Dilcher & al. [47], and Ephedra in having ovulate cones with only one fertile whorl in addition to the ephedroid vegetative morphology, but differs from the latter genera mainly in having unspecialized and verticillate bracts [35,40,47,49,51,52,54]. In Gurvanella, the two to three bracts are specialized in shape and possess unusual furcate venation [47], which makes it easily distinguished from Jianchangia.…”

“…Palaeobotanical studies are promising because early fossils are filling gaps between these morphologically isolated families. Many gnetalean macrofossil plants have been reported from the Lower Cretaceous in Australia [24], Europe [25,26], North America [25][26][27][28], South America [29][30][31][32][33][34][35][36][37], and particularly the Yixian Formation of western Liaoning, northeastern China [15,[38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54]. These fossil plants display a wide range of morphological diversity including leaf/bract and cone morphology, and are important in evolutionary studies of the early gnetophytes.…”