Deep in shadows, deep in time: the oldest mesophotic coral ecosystems from the Devonian of the Holy Cross Mountains (Poland)

作者：Zapalski Mikolaj K^*; Wrzolek Tomasz; Skompski Stanislaw; Berkowski Blazej

来源：Coral Reefs, 2017, 36(3): 847-860.

DOI：10.1007/s00338-017-1575-8

• Platy corals
• Devonian
• Photosymbiosis
• Mesophotic
• Tabulate corals

Recent mesophotic coral ecosystems (MCE) occur at depths between 30 and 150 m and are characterized by dominance of platy corals. Such morphology is an effect of specific adaptation to efficient light harvesting. Here, we describe and analyze platy coral assemblages from two Middle Devonian localities in the Holy Cross Mountains (Poland) that during this time were located on the southern shelf of Laurussia at tropical latitudes. The Eifelian argillaceous sediments of Skaly are dominated by platy and encrusting tabulate corals (Roseoporella, Platyaxtan and Alveolites). Coeval faunas from the shallow water parts of the Holy Cross Mountains basin display bulbous and branching morphology, thus indicating a Paleozoic coral zonation similar to that known in the Recent. Hence, the Skaly site seems to be the oldest known MCE (ca. 390 Ma). A Givetian biostrome from Laskowa Quarry is a second example dominated by platy corals, with abundant branching forms; this site can be recognized as another Devonian MCE. Frondescent Platyaxtan, common at both sites, had a growth habit similar to that of Recent Leptoseris, Mycediutn or Pavona. Platy morphology is photoadaptive and may evidence photosymbiosis in tabulate (Alveolites, Roseoporella, Platyaxutn) and rugose corals (Phillipsastrea). Furthermore, it may serve as a tool for recognition of the lower euphotic zone in the fossil record.

• 出版日期2017-9