16 CALCAREOUS ALGAE OF THE MIDDLE EAST 



Costantin (1920) which gives some of Munier-Chalmas' original figures. The recent 

 .[aciduria has been merged as a section Acicularioides of Acetabularia (Egerod 1952), 

 but in the fossil state at least the remains are distinctive and the name a useful one. 



Acicularian spicules are typically small elongate needle-like calcareous bodies, 

 derived from the specialized fertile disc of the plant and containing tiny spherical 

 sporangial cavities. (Somewhat similar discoidal or spherical bodies, Terquemella 

 of Munier-Chalmas were recognized by the Morellets as sporangial structures from the 

 walls of fossil Bornetelleae (= Dactyloporeae), which are of normal tubular dasyclad 

 pattern and not umbrella-shaped like Acicidaria or Acetabularia) . Both morpho- 

 logical types of spicule are known from the Jurassic onwards. Whilst the attribution 

 of the Tertiary species is as given above, the origin of the Mesozoic forms is much 

 more doubtful. Pia (1936a, b) has described Cretaceous spicules which he referred 

 to Acicularia but considered might indicate a connection between Acicularia and 

 Terquemella, obviously using the latter in a strictly morphological sense. 



In the Middle East true Terquemella spp. occur in the Palaeocene-Lower Eocene ; 

 these species are dealt with below under Terquemella. The remaining Acicularia 

 spp. are now described here. 



Acicularia antiqua Pia 



(PI. 1, figs. 1, 3) 



1936a Acicularis antiqua Pia : pi. 3, figs. 1-14. 

 1955b A. cf. antiqua Pia ; Elliott : 126. 



Description. Rounded, cuneiform, calcareous bodies, circular or ovoid in cross- 

 section, containing numerous submarginal spherical hollows (sporangial cavities). 

 Length up to 0780 mm., with maximum diameter of 0-364 mm. The sporangial 

 cavities are consistently about 0-040 mm. in diameter, and in thin-section appear 

 set apart by their own diameter or a little more along the margins of the spicules. 



Horizon. Cretaceous of North Africa and the Middle East. 



Material. Seen in thin-section from the subsurface Garagu formation (Valan- 

 ginian) of Kirkuk well No. K 116 (Kirkuk Liwa, Iraq), from the Sarmord and 

 Qamchuqa formations (Neocomian and Aptian-Albian) of the Surdash district 

 (Sulemania Liwa, Iraq), from the Upper Musandam formation (Lower Cretaceous, 

 Barremian-Aptian) of the Hagab area, Oman, Arabia, and from the Maestrichtian 

 of Diza, (Erbil Liwa, Iraq). 



Remarks. Random sections of acicularian spicules are not uncommon at many 

 levels in the Middle East Cretaceous. With few exceptions, they may be divided 

 into two classes, on the size of the sporangial cavities. The smaller, always set in a 

 circular section indicating a spherical spicule, is described elsewhere under Terque- 

 mella s.l. The larger, described above, occurs in a variety of random cuts suggesting 

 a rounded-cuneiform spicule. For this form Pia's Acicularia antiqua (Pia, 1936a) 

 appears to be available. The type material, from the Cenomanian of Libya, 

 Northern Africa, is described as probably wedge-shaped or pointed, length probably 

 not exceeding twice the thickness, greatest diameter 0-330 mm., diameter of spore- 



