9-2 



CALCAREOUS ALGAE OF THE MIDDLE EAST 



but Broeckella, Clypeina and Terquemella occur in both as well as in the Middle East, 

 and Pagodaporella is so far known only from the Middle East. This assortment of 

 genera in the very sector of the Tethys which in mid-Tertiary was to become the land 

 barrier dividing the marine Mediterranean-Antilles from the Indo-Pacific is no doubt 

 significant for the modern discontinuous distribution of dasyclads, even if most of the 

 genera quoted are now extinct. The distribution-maps (Figs. 8-14) illustrate 

 different aspects of past and present dasyclad occurrences. The value of these dated 

 fossil occurrences may be seen by a comparison with the distribution-maps of 

 Svedelius (1924) which, whilst taking account of former continuous sea-ways, show 

 only Recent distribution. 



The work of Kaever (1965), on the micropalaeontology of Afghanistan, contains 

 numerous records of Tethyan algal species familiar in the Middle East. Unfor- 

 tunately this paper came too late to my notice for inclusion of the detailed species 

 records. 



VI. ECOLOGY 



At the present day dasyclads are a relatively inconspicuous element in marine 

 algal floras. Although life has sometimes taken me to warm-water shores, I have 

 never seen or collected living dasyclads. Their ecology has been briefly summarized 

 by Pia (1920), Cloud (1962) and Johnson (1961b), all palaeontologists, for comparison 

 with fossil occurrences. They occur in warm shallow coastal waters in sheltered 

 situations in tropical and subtropical seas, and in areas marginal to the latter, such as 

 the Mediterranean. Their maximum abundance is said to be from low-tide level to 

 5-6 m. depth, extending down in diminishing abundance to 10 m., and with scattered 

 occurrences below this to 30 m. or more, depending on intensity of illumination and 



Distribution of the Polaeocene 

 Pagodaporella, and its possible 

 living descendant Dosyclodus. 



Approximate Telhyan Margin 



■ Pagodaporella (Polaeocene) 

 Q Dosyclodol (Recent] 



Fig. 14. 



