A Caribbean epiphyte community preserved in Miocene Dominican amber

Abstract

Fossil tree resins preserve a wide range of animals, plants, fungi and microorganisms in microscopic fidelity. Fossil organisms preserved in an individual piece of amber lived at the same time in earth history and mostly even in the same habitat, but they were not necessarily parts of the same interacting community. Here, we report an in situ preserved corticolous community from a piece of Miocene Dominican amber which is composed of a lichen, a moss, and three species of leafy liverworts. The lichen is assigned to the extant genus Phyllopsora (Parmeliaceae, Lecanoromycetes) and described as P. magna Kaasalainen, with open areas, and were rich in epiphytes (Grimaldi, 1996). Based on its animal and plant inclusions, the Dominican amber forest has been characterized as a moist tropical forest, which was not remarkably different from the modern Neotropical lowland rainforest (Grimaldi 1996; Poinar & Poinar 1999). Three species of lichens, 22 species of liverworts, and 29 species of mosses have so far been described from Dominican amber, of which the liverworts clearly represent extinct taxa (Poinar et al. 2000;Rikkinen & Poinar 2008; Heinrichs et al. 2015a). Also the fossil lichens have been described as representatives of extinct species, however, the absence of several important chemical and apothecial characters hinders a reliable differentiation between the fossil and morphologically similar extant species (Poinar et al. 2000;Rikkinen & Poinar 2008 DNA sequence variation of extant species provides certain likelihood for a species age that is in accordance with the age of the amber (Heinrichs et al. 2013b, Villarreal & Renner 2014 Heinrichs et al. 2015b;Váňa et al. 2015).Here, we present a piece of Dominican amber that provides a window on a Miocene Caribbean epiphyte community. The virtually in situ preserved cryptogamic community includes a new species of the extant lichen genus Phyllopsora, a moss that is similar but clearly distinguished from the modern genus Aptychella and therefore assigned to the new fossil genus Aptychellites, as well as three extinct species of the extant leafy liverwort genera Cheilolejeunea, Lejeunea, and Radula. The members of this community are distinct from extant Caribbean species, further substantiating the notion of a stasis in morphotype diversity but a certain turnover of species in the Caribbean since the early Miocene as recently suggested by Schneider et al. (2015). It is also in line with the hypothesis of Poinar and Poinar (1999) that many of the plants and animals preserved in the Miocene Dominican amber do not have immediate extant descendants. Material & MethodsThe fossilized epiphytes are preserved in a ca 3 cm x 2 cm x 0.8 cm sized piece of Dominican amber which is housed in the amber collection of the American Museum of Natural History in New York (AMNH DR-15-3). The amber specimen originated from the amber mines in the Cordillera of the Dominican Republic.The mines in the Northern, Eastern and Western parts of the Dominican Republic yield ambers with an...

A Burmese amber fossil of <i>Radula</i> (Porellales, Jungermanniopsida) provides insights into the Cretaceous evolution of epiphytic lineages of leafy liverworts

“…The recently proposed fossilized birth-death approach was designed to overcome the problem of assigning fossils to certain nodes in divergence time analyses (Heath et al, 2014); however, this approach requires a dense fossil record and numerous morphological character states of both fossils and extant taxa to be coded (Arcila et al, 2015;Warnock et al, 2015). We were unable to successfully employ this approach because of the small number of Radula fossils, their incomplete preservation, and the monotonous morphology of both the majority of extant and fossil species (Grolle, 1987;Renner and Braggins, 2004;Renner, 2015;Heinrichs et al, 2016b;Kaasalainen et al, 2017).…”

“…; and R. sphaerocarpoides Grolle (Heinrichs et al, 2016b) and the Miocene Dominican amber fossils R. steerei Grolle (Grolle, 1987) and R. intecta M. A. M. Renner, Schäf.-Verw. & Heinrichs (Kaasalainen et al, 2017). The subgeneric affiliation of these fossils is unclear and, accordingly, they were not assigned to any crown group node of Radula in divergence time estimates based on DNA sequence data of extant species (Patiño et al, 2017).…”

Diversity and ecological adaptations in Palaeogene lichens

“…Fossilized lichens have appeared to be extremely rare, with only 15 unambiguous fossils described so far [10][11][12][13] . The oldest lichen fossils are known from the Early Devonian [14][15][16] , and one Mesozoic fossil has been described from the Early Cretaceous 10 .…”

The leafy liverwort genus Lejeunea (Porellales, Jungermanniopsida) in Miocene Dominican amber

“…The recently described Lejeunea miocenica (Kaasalainen et al, 2017) has variably shaped leaf lobes with obtuse to acute apices, an asperulate cuticle and sometimes crenate lobe margins.…”