Fig. 3. Acanthochaetetes fischeri n in Acanthochaetetes Fischeri N. Sp. (Coralline Demosponge) From The Upper Paleocene (Thanetian) Of Iraq (Kurdistan Region) And Iran (Sistan Suture Zone)

Fig. 3. Acanthochaetetes fischeri n. sp. from the upper Paleocene of eastern Iran (a–b) and northeastern Iraq (c–f). a Longitudinal section, showing notable walls (yellow arrows) and tabulae (black arrows), the latter occurring seldom. Thin-section 2pz 93. b Longitudinal section, with spines within calicles, diagnostic for the genus Acanthochaetetes Fischer (yellow arrows). Spines in only one calicle are shown. Note also the huge intertabular space (between red arrows), measuring> 2 mm as a rule. In addition, thick double walls, diagnostic for A. fischeri n. sp. can be seen (black arrows). A fissiparous division process (black square) is highlighted. Thin-section 2pz 95. c–e Oblique section, where the high density of calicles/mm2 (1.5 to 2.5) can be confirmed. This trait can also be seen in d and e especially in the marked areas (squares). Thin-sections 24, 15, and 14. f Cross section, showing the remarkably thick double walls (red arrows), which can attain up to 0.3 mm. See text and table 1 for further details. Thin-section 26. Abbreviations: mb= macroboring (e.g. Gastrochaenolites-type), tb = tubulae.