66 CALCAREOUS ALGAE OF THE MIDDLE EAST 



Pianella pygmaea (Gumbel) Radoicic 

 (PI. 17, figs. 6-8) 



1891 Gyroporella pygmaea Gumbel : 306, text-figs. 6, 7. 



1924 Macroporella pygmaea Gumbel spec. ; Pia : 84, pi. 1, figs. 4-7. 



1955a Macroporella pygmaea Gumbel ; Carozzi : 40, pi. 6, fig. 3 ; text-figs. 5, 6. 



i960 Macroporella pygmaea (Gumbel) ; Elliott : 222. 



1962 Pianella pygmaea (Giimb.) Rad. ; R. RadoiciC : 202. 



Description. Calcified cylindrical dasyclad tube, external diameter 0-33-078 

 mm., internal diameter 0-10-0-34 mm. (d/D 27-43%, usually about 30%), showing 

 consecutive horizontal verticils of branches, about 18-20 verticils per mm. of length, 

 each verticil of 15-20 branches. The branches are straight, unbranched, near- 

 circular in cross-section, and widen radially with straight sides to the exterior, from a 

 very narrow insertion on the stem-cell cavity to the exterior where they have a 

 diameter of about 0-052 mm., sometimes with a terminal widening to give a diameter 

 of 0-090 mm. 



Horizon. Upper Jurassic to bottom Cretaceous (Sequanian-Valanginian) of 

 Central and Southern Europe (Switzerland, Italy, Southern Germany), Middle East 

 and Borneo. 



Material. In the Middle East, from the Garagu Formation (Valanginian), sub- 

 surface at Awasil no. 5 well and Mileh Tharther no. 1 well, both Dulaim Liwa, Iraq. 

 Also from the Upper Jurassic of the Jebel Laut area, Wahidi State, Hadhramaut, 

 and see Hadhramaut record of Beydoun (i960 : 140). 



Remarks. P. pygmaea from the Middle East is closely comparable in dimensions 

 and structure with the European material described by Pia and by Carozzi (ref. 

 Carozzi 1955a). The external diameter of the pores is usually less (0-05 mm. com- 

 pared with 0-09 mm.), though not invariably so. Of comparable species, P. grudii 

 Radoicic, from the Kimmeridgian of Jugoslavia, is a smaller species with proportion- 

 ally wider stem-cell ; P. tosaensis Yabe & Toyama, from the Upper Jurassic of Japan, 

 shows about 30 branches per verticil, and these are polygonal in cross-section, with 

 expanded outer terminations. 



Genus PSEUDOEPIMASTOPORA Endo 1961 



Diagnosis (after Endo). Thallus short-elliptical, somewhat undulating, almost 

 circular in cross-section ; branches widening within the wall-thickness to spherical 

 cavities (believed sporangial) and narrowing again, set at right angles and slightly 

 ascending to the vertical axis, and may be arranged as definite verticils. 



Pseudoepimastopora was instituted by Endo (1961) to include those species of the 

 older genus Epimastopora s.l. in which the pores seen penetrating the walls swell from 

 a narrow entry to a more or less globular cavity within the wall-thickness and con- 

 strict again : these swellings were considered sporangial in origin. This left 

 Epimastopora s.str. for species in which the pores traverse most of the wall thickness 

 with little change in pore-diameter. Buri (1965) does not regard this division as 

 significant, or of generic value. I agree that it may not be evidence of evolutionary 



