Additions to the family Miroviaceae (Coniferae) from the Lower Cretaceous of West Greenland and Germany: Mirovia groenlandica n. sp., Tritaenia crassa (Seward) comb, nov., and Tritaenia linkii Magdefrau et Rudolph emend.

Abstract

The genus Tritaenia with its type species T. linkii Magdefrau et Rudolph emend, from the Wealden of Germany has been referred to the family Miroviaceae Bose et Manum, comprising Mesozoic and mostly Arctic conifer foliage with ‘Sciadopitys‐like’ stomatal distribution. Two other additions to the Miroviaceae, both from the Lower Cretaceous of West Greenland, arc Pityophyllum crassum Seward, now attributed to Tritaenia, and Mirovia groenlandica n. sp., described on leafy stems and detached leaves. Tritaenia has distinct stomatal bands within the median stomatal zone. This and other stomatal distributions in the Miroviaceae and their implications for the interpretation of leaf venation are discussed with the conclusion that two veins are most likely indicated. Diagnostic characters and stratigraphic and geographic distribution of the presently known miroviaceous taxa are summarized.

A New Sciadopityaceous Seed Cone From the Upper Cretaceous of Hokkaido, Japan

“…A few sciadopityaceous fossil cones have been found in Mesozoic strata (e.g., Menzel, 1913;Bose, 1955Bose, , 1959, but none ofthem has been described anatomically. Among the structurally preserved fossil cones, those of Pseudovoltzia liebeana (Geinitz) Florin, from the Upper Permian of the Rhineland, described by Schweitzer (1963), are similar to the present cone in that they have lobed ovuliferous scales and inverted seeds.…”

“…Many fossil Sciadopitys-like leaves have been reported. However, Bose andManum (1990, 1991) concluded that most of the leaves from northern Europe and adjacent areas are not as similar to those of Sciadopitys as previously thought, and they assigned these leaves into the family Miroviaceae. Under these circumstances, the present specimen is particularly important because it provides evidence of a sciadopityaceous conifer in the Late Cretaceous ofJapan, as well as morphological and anatomical characteristics ofcones ofthe family Sciadopityaceae that supplement the characteristics exemplified by living S. verticillata.…”

Structure and diversity of the Mesozoic wood genus Xenoxylon in Far East Asia: implications for terrestrial palaeoclimates

“…Parichiev (1968) joined Xenoxylon and the extant Taxodiaceae Sciadopitys (the umbrella‐pine, today endemic to Japan) on the basis of their palaeogeographic distribution and on the fact that Xenoxylon and Sciadopitys ‐like foliage are often found associated in Early Cretaceous sedimentary rocks all around the Arctic. It was demonstrated subsequently (Bose & Manum 1990, 1991) that this Sciadopitys ‐like foliage was not related to the modern genus Sciadopitys but to various different genera ( Mirovia , Oswaldheeria , Tritaenia , etc. ), which belong to the extinct family named Miroviaceae.…”

Cone and ovule development inCunninghamiaandTaiwania(Cupressaceae sensu lato) and its significance for conifer evolution

“…Thus, the Majonicaceae from the Permian and Triassic could perhaps have contained a conifer that was the common ancestor of Sciadopitys as well as the taxodiaceous Cupressaceae. Several fossils resembling Sciadopitys from the Jurassic and Cretaceous are now attributed to the fossil family Miroviaceae (Bose and Manum, 1991;Manum, van Konijnenburg-van Cittert, and Wilde, 2000) but could well be closely related to this genus. Sciadopitys itself may also have been present from these periods (Manum, 1987) and was certainly present in the Late Cretaceous (Christophel, 1973;Saiki, 1992) and probably represents the last survivor of a split between its immediate ancestor and a lineage leading to the taxodiaceous Cupressaceae.…”