Wednesday, March 29, 2017

[PaleoBotany • 2017] Protofrullania cornigera • A Fossil Genus of the Frullaniaceae (Porellales, Jungermanniopsida) from the mid-Cretaceous of Myanmar

Protofrullania cornigera Heinrichs

• A liverwort inclusion in mid-Cretaceous Burmese amber is described.
• The fossil is interpreted as a stem group element of extant Frullaniaceae.
• The fossil genus Protofrullania gen. nov. is established.
• Diagnostic are strap-shaped underleaves producing an apical rhizoid bundle.
• Protofrullania cornigera sp. nov. was an epiphyte.

Recent findings established the Albian-Cenomanian amber of Myanmar (Burmese amber) as an important source of Mesozoic cryptogams. Here, we describe an inclusion within Burmese amber as Protofrullania cornigera gen. et sp. nov. in the extant family Frullaniaceae (Porellales, Jungermanniopsida). Diagnostic characters include its incubous leaves consisting of a dorsal lobe and a ventral lobule forming a watersac, and strap-shaped, prominent underleaves producing a rhizoid bundle from the uppermost sector of the long, narrow disc. Bark fragments connected to some of the rhizoid bundles provide evidence that the fossil was an epiphyte.

Keywords: Bryophytes; Liverworts; Mesozoic; Seed-free land plants

Fig. 1. Holotype of Protofrullania cornigera gen. et sp. nov. in Burmese amber (GZG.BST.21956).
A. Upper sector of plant in ventral view. The arrowhead points to a bubble not belonging to the fossil. B. Branch in dorsal view. C. Underleaf (arrowhead) accompanied by watersacs. DE. Branches in ventro-lateral view with helmet-shaped watersacs. Arrowhead points to an underleaf. Most leaf lobes detached or turned back. F. Detail of plant in ventral view. Arrowheads indicate underleaves. G. Detail of plant in ventral view. Each white arrowhead points to an underleaf, black arrowhead indicates a rhizoid bundle.

Scale bars: 300 μm (A), 150 μm (B, D, F); 50 μm (C), 100 μm (E, G). 

Systematic palaeontology

Classification Marchantiophyta, Jungermanniopsida, Porellales, Frullaniaceae

Protofrullania Heinrichs, gen. nov.

Etymology. The name indicates a stem group element of Frullaniaceae.

Diagnosis. Plants with incubous leaves consisting of a dorsal lobe and a ventral lobule forming a watersac by enclosure of the anatomical dorsal leaf surface, lobule with narrow stem insertion, and strap-shaped, prominent underleaves carrying a rhizoid bundle in their uppermost sector.

Type species: Protofrullania cornigera Heinrichs, sp. nov.
Holotype. Geoscientific Collections of the Georg August University Göttingen, collection number GZG.BST.21956;  
Locality. Amber mines near Tanai, Ledo Road, 105 km northwest of Myitkyina, Kachin State, Myanmar.

Etymology. The species name points to the ciliately toothed upper sector of the underleaves.
Specific diagnosis. Species of Protofrullania with ciliately toothed underleaves.

Jochen Heinrichs, Kathrin Feldberg, Julia Bechteler, Patrick Müller, Matthew A.M. Renner, Jiří Váňa, Alfons Schäfer-Verwimp and Alexander R. Schmidt. 2017. A Fossil Genus of the Frullaniaceae (Porellales, Jungermanniopsida) from the mid-Cretaceous of Myanmar.
 Cretaceous Research. DOI: 10.1016/j.cretres.2017.02.023

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