A new Neocalamites (Sphenophyta) with prickles and attached cones from the Upper Triassic of China

AXSMITH, BRIAN; SHUQUIN, ZAN; ESCAPA, IGNACIO; FRASER, NICHOLAS

Columbus, Ohio

Congreso; Botany 2012; 2012

Remains of the extinct sphenophyte (horsetail) Neocalamites are most widespread in the Late Triassic and are typically represented by stem and leaf fragments. Here we report on spectacular finds of a new Neocalamites species from the Yangcaougou Formation in Liaoning Province, China. These fossils occur on bedding surfaces dominated by nearly complete aerial stems with attached leaf whorls and occasional bractless cones. They reveal a monopodial growth habit for the stems, which are covered withdownward projecting prickles that probably provided protection against herbivores. Monopodial stems were apparently rare in Neocalamites, and prickles - or any other form of armament - have never before been reported in extinct or living sphenophytes. The nodes bear whorls of extraordinarily long leaves mainly free to their bases. The leaves of adjacent stems mostly likely interlocked to support growth in large stands akin to the role now played by branches in large modern Equisetum species. The new Chinese Neocalamites is among the most confidently reconstructed example, and indicates a greater diversity of sphenophyte morphology during the Mesozoic than previously realized.