Article: Affinity of Tubiphytes
Robert Riding and Li Guo
Tubiphytes Maslov, 1956 is a problematic fossil which ranges from early Carboniferous to mid-Cretaceous and is common in Permian and Triassic reef and other shallow marine carbonate facies. It has been suggested to be a cyanobacterium, hydrozoan, sponge, red alga, foraminifer, and a cyanobacterium-chlorophyte consortium. Its distinctive morphological features include densely flocculent and layered skeletal structure, an axial canal system which may or may not be integral to Tubiphytes, and smoothly rounded to encrusting external form. Cyanobacterial and algal affinities are discounted. A foraminiferal affinity cannot be ruled out, but is inconsistent with the morphology and organization of most Tubiphytes. The presence of an integral canal system would be consistent with a hydrozoan or sponge affinity, but the absence of other cavities in the skeleton which individuals could occupy does not favour a hydrozoan affinity. There is similarity between the skeletal structure of Tubiphytes and that of archaeocyath exothecal tissue and sponge filling tissue. Tubiphytes appears to have been capable of colonizing deeper and cooler water than algae with which it may also be associated. The family Nigriporellidae Rigby, containing Tubiphytes, is here regarded as belonging to the invertebrates, possibly the Porifera.