Fossil evidence of initial radiation of Cercidiphyllaceae

Abstract

Cercidiphyllaceae-like leaves and fruits from the Lower Cretaceous deposits of Northeastern Asia were restudied. In the result one species of Jenkinsella fruits and five species of Trochodendroides leaves were recognized, including Trochodendroides potomacensis (Ward) Bell, T. buorensis Golovneva, T. sittensis Golovneva, sp. nov., T. vachrameeviana (Iljinskaja) Golovneva, comb. nov., and T. denticulata (Budantsev et Kiritchkova) Golovneva, comb. nov. Two new combinations and one new species are published. These plants had very small leaves and probably were shrubs. Fruits of Nyssidium orientale Samylina from the Barremian-Aptian Starosuchan Formation (Primorye, Russia) have no follicular characters as Jenkinsella fruits. Their affinity, not only to Cercidiphyllum-like plants, but to angiosperms in general, is doubtful. Leaves and fruits of Cercidiphyllum sujfunense Krassilov from the lower-middle Albian Galenki Formation (Primorye) also can not be assigned to Cercidiphyllaceae. Leaves have pinnate, brochidodromous venation and are comparable with those of Asiatifolium elegans Sun, Guo et Zheng, which were recorded from the Frentsevka Formation of the Partizansk coal basin, Primorye, Russia, and from the Chengzihe Formation, Northeastern China. Thus, the first reliable records of the genus Trochodendroides appear in the early-middle Albian. The relationship of these leaves with Cercidiphyllaceae is confirmed by finds of associated fruits Jenkinsella filatovii and by significant diversity of Trochendroides in the Late Albian-Cenomanian. In the early-middle Albian the genus Trochendroides was a minor component of the conifer-dominated Mesophytic floras. These fossils reflect the early radiation of Cercidiphyllaceae and indicate that this family began to diversify more then 30 million years before the Tertiary. Investigation of the early-middle Albian Cercidiphyllaceae provides important new data for our understanding of the early evolution of eudicots.

Plastid phylogenomics and fossil evidence provide new insights into the evolutionary complexity of the ‘woody clade’ in Saxifragales

“…3) showed that all three of the WCS monotypic families (i.e., Altingiaceae, Cercidiphyllaceae, and Daphniphyllaceae) are [59,62]. Within Cercidiphyllaceae, four extinct genera (Jenkinsella, Joffrea, Nyssidium, and Trochodendroides) have been reported [63][64][65][66]. Among them, a Joffrea species has been documented from the late Paleocene of Canada [64]; 10 Jenkinsella, 13 Nyssidium, and 60 Trochodendroides species [67,68] have been discovered across the Northern Hemisphere spanning from early Cretaceous Fig.…”

“…According to the most recent time-calibrated angiosperm phylogeny [29], the stem age of the WCS is constrained to 105.2 Ma. In addition, the earliest fossils of the extinct genera Trochodendroides [66], Allonia/Androdecidua [60,62], and Archamamelis [59,61,62] were chosen to constrain the stem ages of Cercidiphyllaceae (100.5 Ma), Loropetaleae (83.6 Ma), and Hamamelideae (83.6 Ma), respectively. These fossils are either infructescences/fruits or well-preserved flowers with pollen [60,61,66], and their systematic positions have been robustly verified and extensively used for calibrating the phylogeny of angiosperms [e.g., 29,62,105].…”

Angiosperm diversification in the Early Cretaceous of Primorye, Far East of Russia

“…However, during the Late Cretaceous, Trochodendroides-Jenkinsella-Alasia fossils were widespread in middle and high latitudes of the Northern Hemisphere. In the lowermiddle Albian deposits of Northeastern Asia, they are represented by one species of Jenkinsella fruits and five species of Trochodendroides leaves from different localities (Golovneva and Zolina 2018). These fossils reflect the early history of Cercidiphyllaceae or its ancestors.…”

“…This leaf is very similar to leaves of Trochodendroides sittensis Golovn. from earlymiddle Albian Khatyryk Formation of the Lena River basin, Yakutia, Russia (Golovneva and Zolina 2018).…”

“…from the lower-middle Albian Galenki Formation is very similar with T. sittensis Golovn. from the lower-middle Albian Khatyryk Formation, Lena River basin, Eastern Siberia, Russia (Golovneva and Zolina 2018). Leaves of Trochodendroides are associated with fruits Jenkinsella (Nyssidium) and inflorescences Alasia Golovn.…”