Parmotrema specimen 4

Parmotrema specimen 4 View in CoL View at ENA

Specimen.

Geoscientific Collection of the University of Göttingen, Germany ( GZG), GZG.BST.22085 ; syninclusion Frullania chiapasensis .

Age and stratigraphic level.

15‒23 Ma, Langhian – Aquitanian (early to middle Miocene), Simojovel, Chiapas, Mexico.

Description.

Lichen fragment approximately 2.3 × 4.5 mm in diameter. Thallus foliose, lobate. Lobes flat and linear, 0.5-1.0 mm wide, lobe apices truncate to slightly rounded (Fig. 8 D View Figure 8 ). Upper surface smooth, brown (Fig. 8 D View Figure 8 ). Marginal cilia dark, mainly simple, up to 0.5 mm long (Fig. 8 D View Figure 8 ). Medulla not visible. Lower cortex concolorous with the upper surface (Fig. 8 E View Figure 8 ). Rhizines dark, abundantly branched (Fig. 8 E View Figure 8 ). Apothecia, isidia, soredia, or pycnidia not present.

Discussion.

The general habit and long, tapering marginal cilia identify the specimen as Parmotrema . The branching rhizines and long, tapered marginal cilia resemble the Canomaculina group. However, unlike the Canomaculina group, the fossil inclusion seems to possess a smooth upper surface of the lobes that visibly lack maculae.