150 



H.W. PALM 



39 



Fig. 39 Heteronybelinia robusta. Scolex from Carcharhinus limbatus. Scale bar=100 um. 



Fig. 40 H. robusta Heteromorphous metabasal armature, bothridial (right hand side) and antibothridial (left hand side) surfaces. Scale bar=10um. 



Fig. 41 H. robusta. Heteromorphous basal armature, antibothridial surface. Scale bar=10 um. 



of the strobila respectively. Ovary centally, follicular, with 2 major 

 branches. 



Remarks. The scolex measurements as well as the form and size 

 of the tentacular armature correspond with those in the original 

 description (Dollfus, 1960) and those of specimens from the Mo- 

 zambique coast (Palm et. al., 1997). A high variability in scolex 

 morphology has been described from 20 specimens of 7 host species 

 by Palm et al. (1997). However, H. yamagutii is easily distinguish- 

 able from all other Heteronybelinia species by its metabasal tentacular 

 armature consisting of large claw-like hooks and its basal armature 

 consisting of smaller hooks and characteristic bill hooks. Adult H. 

 yamagutii is a large trypanorhynch with segments of different shape 

 and size along the strobila. The testes number as well as the size of 

 testes and vitellaria also vary along the strobila. The present finding 

 is the first report of adult H. yamagutii, occurring in Sphyrna lewini 

 from South Africa. A world-wide distribution for the species has 

 been proposed by Palm et al. (1997). 



Mixonybelinia gen. nov. 



Trypanorhynchs with the characters of the Tentaculariidae Poche, 

 1926. Scolex compact, 4 triangular bothridia, with hook-like 

 microtriches along the bothridial borders and filamentous 

 microtriches on the rest of the bothridia and the scolex. 4 tentacles 

 emerging from bulbs, the retractor muscle originates at the base of 

 the bulbs. 4 proboscides of various length and width, armed with 

 massive hooks; metabasal tentacular armature homeoacanthous with 

 heteromorphous hooks on different tentacle surfaces. Characteristic 

 basal armature consisting of homeomorphous hooks present. Cirrus 

 unarmed, cirrus sac alternates irregularly. 



TYPE SPECIES. Mixonybelinia beveridgei (Palm, Walter, 

 Schwerdtfeger & Reimer, 1997) (subgroup II in Palm et al., 1997). 



OTHER SPECIES. Mixonybelinia southwelli (Palm & Walter, 1999) 



16. Mixonybelinia beveridgei (Palm, Walter, 

 Schwerdtfeger & Reimer, 1997) comb. nov. 



Material examined. The Natural History Museum London: 



