Morphometrics and palaeoecology of syringoporoid tabulate corals from the upper Famennian (Devonian) Etoucun Formation, Huilong, South China

Syringoporoid tabulate corals are one of the most common benthic sessile organisms in the upper Famennian Etoucun Formation at the Huilong section, Guilin, South China. A multivariate morphometric analysis based on five morphological characters was applied to 29 coralla from three intervals in the formation. Cluster analysis, principal coordinate analysis, non-metric multidimensional scaling, and an examination of the qualitative morphological characteristics revealed the presence of four morphospecies representing Chia hunanensis Jia, 1977, Tetraporinus virgatus Tchudinova, 1986, Fuchungopora multispinosa Lin, 1963, and a new species designated as F. huilongensis. Interval A belongs to foraminifer biozones DFZ4 to DFZ6 and contains abundant C. hunanensis and scattered coralla of T. virgatus, whereas intervals B and C which are within foraminifer biozone DFZ7 contain abundant F. multispinosa, sporadic F. huilongensis, and rare fragmented corallites of C. hunanensis. The coralla are commonly tilted or overturned, which is especially obvious in intervals B and C, indicating that most of them settled on a soft substrate and were subjected to periodic high-energy events. The species of Fuchungopora display flexible growth strategies characterised by the fusion of their corallites. The high diversity of syringoporids recorded from South China indicates an obvious radiation of the tabulate corals in the uppermost Famennian. Syringoporids accounted for the majority of tabulate corals recorded in South China in the upper Famennian and represented a relatively high level of palaeobiodiversity before the Hangenberg Crisis.