A Winteraceae pollen tetrad from the early Paleocene of western Greenland, and the fossil record of Winteraceae in Laurasia and Gondwana

Abstract

Aim Winteraceae comprise c. 130 species in seven genera, with the greatest species diversity in the Pacific (Pseudowintera, Zygogynum), Australia (Bubbia, Tasmannia), New Guinea (Belliolum, Bubbia, Zygogynum, Tasmannia) and Madagascar (Takhtajania). Only Drimys occurs in South America. Because of their Cretaceous leaves, wood and pollen fossils, and their lack of xylem vessels, Winteraceae throw light on early angiosperm evolution. We describe a Winteraceae pollen tetrad from the Paleocene of Greenland, review the family's fossil record and palaeogeography and document its current climate preferences. Location Worldwide. Methods Extant and fossil pollen were studied with light and scanning electron microscopy. Molecular phylogenetic and character mapping approaches were used to infer the evolution of pollen characters, and 37,842 collections from the Global Biodiversity Information Facility were used to infer the climate and vegetation types occupied by today's Winteraceae and to compare them to the Paleocene climate and vegetation of Greenland as inferred from the fossil record of other families. Results Winteraceae are the only flowering plants with persistent, acalymmate tetrads composed of ulcerate grains with a distinct reticulate sculpturing. The tetrad described here as Pseudowinterapollis agatdalensis Grímsson & Zetter spec. nov. comes from Agatdalen valley in western Greenland and dates to the Early Paleocene, Danian, 64–62 Ma. It shows the complete character suite of modern Winteraceae and overlaps the LM characters of the three previously known Pseudowinterapollis species from Australia, New Zealand and South Africa. The palaeoflora of the Agatdal Formation consisted of a mixed deciduous–evergreen forest resembling habitats where Winteraceae occur today. Main conclusions Macro‐ and microfossil records of Winteraceae extend back to the Upper Cretaceous in both Laurasia and Gondwana, and the family's biogeography, like that of its sister family, Canellaceae, cannot be understood by focusing only on southern Gondwana. Winteraceae instead were part of broadleaved forests in Paleocene and Eocene North American and Greenland and may have reached Europe via the North Atlantic Land Bridge, explaining Eocene Winteraceae wood in northern Germany.

Vectors of disease at the northern distribution limit of the genus Dermacentor in Eurasia: D. reticulatus and D. silvarum

“…With this dataset, each tick location can be related to a specific climate class in order to calculate a histogram. Recent application of this so-called Köppen profile were, for example, presented by Grímsson et al (2018) and Rubel et al (2018).…”

“…Recent application of this so-called Köppen profile were, for example, presented by Grímsson et al. ( 2018 ) and Rubel et al. ( 2018 ).…”

An early record of a vesselless angiosperm from the middle Cenomanian of the Envigne valley (Vienne, Western France)

“…Although extant Winteraceae are only distributed in the Southern Hemisphere, fossils attributed to this family (leaves, wood and pollen) have been reported from both Northern and Southern Hemispheres (for a review see Doyle 2000, Friis et al 2011and Grímsson et al 2018. Winteraceae have a unique type of pollen/tetrad easily recognizable (Walker & Walker 1984;Grímsson et al 2017).…”

First fossil record of Cedrelospermum (Ulmaceae) from the Qinghai–Tibetan Plateau: Implications for morphological evolution and biogeography

“…The morphological evolution and biogeographical history of plants can be understood mainly by three lines of evidence: genetic material, morphology, and fossils (Manchester, 1999;Hunt & Slater, 2016;Gr ımsson et al, 2017). However, for the case of extinct taxa, fossils are the only evidence.…”