Typhlopleura dichotoma
Schrammen 1902
Typhlopleura dichotoma (= Pleurostoma dichotoma Schrammen 1912) Typhlopleura dichotoma is a rare sponge at Misburg. It forms thin-walled forking tubes, constructed from hexactine spicules. The tubes may be open ended, as in the picture to the left and below, or closed. The tube cross section is oval. The tube walls are perforated by oval openings, approximately 5 mm wide, which are aligned in two coaxial rows along the narrow sides of the tubes. The outer surface of the sponge shows numerous small pores (ostia) which are arranged in a very regular and characteristic pattern of radiating rows (see pictures). Pleurostoma dichotoma occurs as large groups of branched tubes, covering areas of a quarter m2 and perhaps more.
Well preserved, typical example of an open-ended tube, showing rounded margins and characteristic folding.
Note regular arrangement of pinhole-sized pores.