Coral species of the Indian Ocean and adjacent seas: a synonymized compilation and some regional distributional patterns

A l i s t i s provided of hermatypic cora l species from 24 locations i n the Indian Ocean and i t s per iphera l seas and g u l f s . S ix s i t e s a r e newly reported or expanded accounts, and eighteen a r e derived from recent l i t e r a t u r e . This i s intended: (1) t o provide i n one place, a uniform compilation of cora l species from d i f f e r e n t areas and from many diverse accounts; ( 2 ) t o apply synonyms t o a l l s i t e s i n a consis tent way f o r t h e f i r s t t ime, s o t h a t ; ( 3 ) regional analys is a t species l eve l i s poss ib le . Synonyms a re taken mainly from two recent taxonomic s e r i e s , but because species s t a b i l i t y is poor i n some genera and authors may d i f f e r i n t h e i r views on synonymy, a l l names a r e shown. The sources of da ta were se lec ted t o reduce problems inherent i n using diverse mate r i a l , and many sources themselves include compilations and synonymys of much older works. From 7 9 6 e n t i t i e s i n i t i a l l y obtained, the removal of synonyms and e n t r i e s named "sppI1 leaves 439 species . Further reduction is probably needed. Species r i c h s i t e s extend across the Indian Ocean, with no westerly decl ine from South East Asia; t h e Red Sea as a whole contains t h e most species . Clus ter analys is shows geographical groupings i n t h e Arabian Gulf/Arabian Sea area , i n t h e Red Sea and i n t h e southwest and c e n t r a l Indian Ocean i s l and a reas . Of these , t h e Arabian Group is t h e most separa te . A second analys is corrected f o r d i v e r s i t y d i f ferences a l s o shows t h r e e c l e a r groups: a northern one from t h e Red Sea t o S r i Lanka which includes t h e Arabian group; a l a rge southern o r equa to r ia l region; and a group cons i s t ing of t h e Mergui, Nicobar and Andaman is lands i n t h e Bay of Bengal. Liverpool / Suez Canal Univers i t ies Marine Biology Projec t , Faculty of Science, Suez Canal Universi ty, I smai l ia , Egypt. To da te , most wide s c a l e , comparative work on cora ls i n t h e Indian Ocean and i t s per iphera l seas and gu l f s has been done a t t h e generic l eve l ( S t e h l i and Wells 1971, Rosen 1971, Scheer 1984). Veron (1985a) a l s o shows generic d i v e r s i t y contours i n t h e Indian Ocean, but remarks t h a t t h i s level i s inadequate f o r severa l purposes and he uses species t o discuss d i s t r i b u t i o n s i n the west Pac i f i c . Emphasis on genera has been p a r t l y because s t a b i l i t y a t generic level i s good whereas a t species l eve l it is much l ess so, but a l s o it is due t o the d i f f i c u l t y of obtaining comparable and r e l i a b l e l i s t s of species from a s u f f i c i e n t number of l o c a l i t i e s . Nevertheless, t h e species level i s arguably t h e only b io log ica l ly meaningful one s ince higher taxonomic levels a r e l a rge ly syn the t i c , and moreover, work a t generic level has t h e important drawback of t r e a t i n g a l l genera a s equivalent regardless of whether they contain one o r a great number of species . In t h e l a s t 15 years taxonomic accounts and l ists of cora l s a t species level from t h e Indian Ocean have become more numerous although they a r e widely dispersed i n t h e l i t e r a t u r e . Their increase has p a r t l y been due t o a dramatic improvement in t h e l i t e r a t u r e avai lable f o r cora l i d e n t i f i c a t i o n , e spec ia l ly from t h e taxonomic s e r i e s of Veron and coworkers and of Scheer and P i l l a i (Veron and Pichon 1976, 1980, 1982, Veron e t a1 1977, Veron and Wallace 1984, Scheer and P i l l a i 1974, 1983, P i l l a i and Scheer 1976). An e a r l i e r p l o t of d i v e r s i t y contours a t species level (Sheppard 1983) showed t h a t the re is a much smaller and l e s s regular drop i n d i v e r s i t y away from t h e e a s t Asian region than is seen a t generic l eve l . The p l o t was not based on f u l l y syrionymised l is ts but it suggested t h a t , numerically a t l e a s t , t h e Indian Ocean might be more uniform than the Pac i f i c , a point a l s o made by Veron (1985a). Since then, new o r expanded l is ts have become avai lable f o r a t l e a s t s i x more areas i n previously poorly known p a r t s of t h i s region. Also it is s t i l l t h e case t h a t d i f f e r e n t formats and use of synonyms by d i f f e r e n t authors makes regional comparisons unnecessari ly d i f f i c u l t . To help overcome t h i s the re fo re , t h e present l i s t was compiled t o include accounts, i n a uniform manner and using the same synonyms, from a t o t a l of 24 Indian Ocean s i t e s . The f u l l l i s t i n g is given here i n order t o f a c i l i t a t e fu r the r work a t species l eve l , and t h e r e s u l t of an i n i t i a l analys is of t h e da ta is reported. In t h e Indian Ocean general ly, knowledge of cora l faunas remains patchy. Very large areas of coast a r e scarcely v i s i t e d and many v a s t , shallow limestone banks and a t o l l groups a r e completely unstudied. Recently, descr ip t ions of a l l known, important co ra l r ee f s i n t h e region have been compiled i n t o one volume (Sheppard and Wells i n p r e s s ) , but t h i s focuses , on t h e nature , condition and conservation s t a t u s of r ee f s and excludes any s i g n i f i c a n t treatment of t h e cora l species themselves. The present work the re fo re , i s a l s o intended t o complement t h e volume by providing data on cora l species , t o t h e extent t h a t t h i s i s poss ib le a t t h e present time.