A new gymnospermous wood found from NW China and its climate implication of mid-latitude NE Pangaea

Permineralized woods and isolated axes have been documented from numerous Permian localities of northern China. However, most of the previous observations focused on fossil woods from the Cathaysian floral province. Few Permian woods have been investigated from the Subangaran floral province in China.

Septomedullopitys szei sp. nov. is discovered and described from the Wuchiapingian Wutonggou low-order cycle (roughly equivalent to Wutonggou Formation) in Tarlong valley, southern Bogda Mountains, Xinjiang, northwestern China. The stem has a heterogeneous pith approximately 15-20 mm in diameter containing numerous straight secretory ducts and parenchymatous bands. Primary xylem is endarch and the tracheids contain scalariform thickenings. Secondary xylem is of the Protophyllocladoxylontype. Comparisons with contemporaneous gymnosperm woods containing either solenoid pith or Protophyllocladoxylon type secondary xylem and from the (Sub)Angara landmass indicate that the Tarlong stem represents a new Permian morphotaxon for the region. The presence of coprolites, borings, and spindle-like cavities within the stem suggests well-developed animal-plant-fungi interactions in the Wuchiapingian time. The presence of numerous growth interruptions and absence of true growth rings within the stem suggest that the climate did not minimal annual temperature and/or precipitation seasonality. The interruptions suggest a humid-subhumid climate with short-term, nonperiodic droughts. 

This research was supported by Chinese Academy of Sciences, National Basic Research Program of China, the National Natural Science Foundation of China and Missouri University of Science and Technology. 

Related information of this paper: Mingli Wan, Wan Yang, Jun Wang *, 2014. Septomedullopitys szei sp nov., a new gymnospermous wood from Lower Wuchiapingian (Upper Permian) continental deposits of NW China, and its implication for a weakly seasonal humid climate in mid-latitude NE Pangaea. Palaeogeography, Palaeoclimatology, Palaeoecology, 407: 1-13. doi: 10.1016/j.palaeo.2014.04.011