Parmotrema undetermined-3

Parmotrema specimen 3 Specimen. American Museum of Natural History, New York, AMNH DR-14-294. Age and stratigraphic level. 15‒20 Ma, Langhian – Burdigalian (early to middle Miocene), La Toca Formation, Dominican Republic. Description. Lichen fragment approximately 1.7 × 1.3 mm in diameter. Thallus foliose, lobate. Lobes flat, linear, approximately 0.5 mm wide and 40 µm thick, lobe apices truncate to rounded. Upper surface slightly uneven with effigurate maculae, with prominent dark margins (Fig. 8 A). Marginal cilia long (up to 0.9 mm), branching, tapering (Fig. 8 A). Medulla pale (Fig. 8 C). Lower cortex dark (Fig. 8 B, C). Rhizines dark, mainly simple (Fig. 8 B). Apothecia, isidia, soredia, or pycnidia not present. Discussion. The general habit and long, branching and tapering marginal cilia identify the specimen as Parmotrema. The effigurate maculae on the upper surface and tapered marginal cilia of Parmotrema specimen 3 resemble the former genus Canomaculina (Elix 1993) which has been synonymized with Parmotrema (Blanco et al. 2005). The Canomaculina group is characterized by tapered cilia, effigurate-maculate upper surface of the lobes, and simple and furcate to branched rhizines (Elix 1993). The Canomaculina group contains more than ten extant species and has a center of distribution in South America (Elix 1993; Blanco et al. 2005).