New Records of Pelliceria (Theaceae/Pelliceriaceae) in the Tertiary of the Caribbean

Abstract

New discoveries of fossil of Pelliceria in Tertiary deposits of the Caribbean extend both the stratigraphic and geographic range of the genus in the Antilles and Central America. The new records include specimens from the Eocene of Jamaica, Eocene of Panama, and Oligo-Miocene of Panama. Factors suggested for explaining the range restriction of Pelliceria, from once widespread throughout the Caribbean, to presently from Pacific Costa Rica to northwestern Colombia, include sea-level fluctuations, climatic trends toward cooler conditions, and competition from extensive communities of Rhizophora which first developed in the Caribbean region during the Oligocene. THE GENUS Pelliceria' is monotypic member of the Theaceae (Pelliceriaceae fide Airy Shaw 1966) presently restricted to lowland coastal areas from Puntarenas in Costa Rica, through Panama and northwestern Colombia, to the Esmeraldas Province of Ecuador (Holdridge, pers. comm. 1976). The single species, P. rhizophorae Planchon and Triana (the 'palo de sal' in Panama), is mangrove but lacks the characteristic prop-roots (cf. Kobuski, 1951: 258). frequently occupies sites where rivers empty into the Pacific (Genuty, pers. comm. 1976), or slightly brackish water zones behind the mesoto euryhaline strand of Rhizophora-Laguncularia-Avicennia. In the mangrove region of the Osa Peninsula of Costa Rica, however, it is associated with Rhizophora in areas of highest salinity. At Main Beach and Playa Grande, Panama, It develops best along the main drainage channels of the swamp in constantly wet soils that are very shallowly inundated at high tide, usually in company with Rhizophora and Laguncularia (Johnston 1949: 207). Pelliceria is small tree, usually between 5-10 m in height but occasionally reaching 20 m. In the Golfo Duke region it has . . . a very straight, unbranched trunk and narrow crown. The trees have very strongly developed, deeply fluted pyramidal buttress at the base, even in young specimens, and are unique in this character in the mangrove association (Allen 1956: 287). Kobuski (1951) and Cuatrecasas (1958) provide further taxonomic and ecological information on the genus. In 1964 van der Hammen and Wijmstra described fossil type, Psilatricolporites crassus, from the Tertiary of the Guiana Basin. Subsequently Langenheim et al (1967) reported Pelliciera-type pollen from the Oligo-Miocene Simojovel Group of Chiapas, Mexico (plate XLII: 315). Wijmstra (1968) recognized the Chiapas specimens as similar to Psilatricolporites, and the biological affinities of the latter were established. Later of Pelliceria was also described from the Oligocene of Puerto Rico (Graham and Jarzen 1969, figs 66-68). Germeraad et al. ( 1968) summarize its stratigraphic range in the Caribbean as basal Eocene to Recent. Thus with the recognition of fossil of P. ctasus as belonging to Pelliceria, the latter, presently restricted to Pacific Central and northern South America, is revealed as once widely distributed mangrove extending from northern South America to south-central Mexico and the Antilles (fig. 1). Recently, new occurrences of Pelliceria have been discovered in the Caribbean Tertiary establishing the genus as even more abundant and widespread. The of Pelliceria is variable both in size and ornamentation. Some specimens have conspicuous mound-like scabrae with fine sub-reticulum evident at lower focal levels (fig. 2A insert, fig. 2B). In others the scabrae are less conspicuous, and the grains are distinctly reticulate (e.g., figs. 2G, H). Size ranges from ca. 40,u to 90u in modern pollen, with moderate percentages of smaller abortative grains present in some preparations. Germeraad et al. (1968) noted these variations and suggested they may represent various states of preservation (viz., erosion of the scabrae). However, comparable range in size and ornamentation is also evident on modern reference slides prepared from single flower. The of Pelliceria is distinct, and similar ranges in size and ornamentation are present in both modern and fossil specimens from the Caribbean.