124 



H.W. PALM AND T. WALTER 



The following measurements were taken: Scolex length (SL), 

 scolex width at level of pars bothridialis (SW), pars bothridialis 

 (pbo), pars vaginalis (pv), pars bulbosa (pb), pars postbulbosa (ppb), 

 velum (vel), appendix (app), bulb length (BL), bulb width (BW), 

 bulb ratio (BR), proportions of pbo/pv/pb (SP), tentacle width (TW), 

 and tentacle sheath width (TSW). If possible, the tentacle length 

 (TL) was estimated. Additionally, the tentacular armature was de- 

 scribed as follows: armature homeomorphous or heteromorphous, 

 hooks per half spiral row (hsr), total hook length (L) and the total 

 length of the base (B). 



All measurements are given in micrometers unless otherwise 

 indicated. Illustrations are provided where useful, otherwise the 

 reader is referred to illustrations of other authors. The classification 

 follows that of Palm ( 1 995 , 1 997 ) and the orientation of the tentacu- 

 lar surfaces follows that of Campbell & Beveridge (1994). 



RESULTS 



The comparison of Tetrarhynchus perideraeus Shipley & Hornell, 

 1906, BMNH 1977.11.4.7-9, 1977.11.11.38 from the Southwell 

 collection with the co-type material of T. perideraeus from the 

 VNHM (2109, 2111) revealed differences. The BMNH material 

 corresponds neither with the co-types from the VNHM nor with 

 specimens of T. perideraeus as re-described by Dollfus ( 1 942. Figs 

 98-100). Similarly, the type material of T. perideraeus from the 

 VNHM clearly differs from the specimens described by Dollfus 

 (1942). Thus, the material deposited and described above belongs to 

 three different Nybelinia species. 



In the following, Nybelinia perideraeus (Shipley & Hornell, 

 1906) is re-described and the material collected by T. Southwell and 

 deposited in the BMNH, which does not fit in any of the currently 

 accepted species (Palm etal., 1997), is described as N. southwelli sp. 

 nov. Another species deposited in the VNHM, Tetrarhynchus 

 herdmani (Shipley & Hornell, 1906), can be considered synony- 

 mous with Kotorella pronosoma (Stossich, 1901) Euzet & 

 Radujkovic, 1989. 



Superfamily TENTACULARIOIDEA Poche, 1926 

 Family TENTACULARIIDAE Poche, 1926 

 Genus NYBELINIA Poche, 1926 



Nybelinia southwelli sp. nov. 



Synonymy. 



N. perideraeus (Shipley & Hornell, 

 1929a, b, 1930) 



(Figs l-3c) 



1906) of Southwell (1924, 



Material described. Holotype, BMNH 1977.1 1.4.7, J. Pearson 

 leg., 30.9. 1 925, 1 adult from Rhina ancylostoma Bloch & Schneider, 

 1801 (=Rhynchobatus anchylostomus) Sri Lanka (Ceylon); Paratype, 

 BMNH 1977.11.4.8-9, J. Pearson /eg., 30.09.1925, 1 adult from 

 Nebrius ferrugineus (Lesson, 1830) {-Gingly mo stoma concolor), 

 Sri Lanka. Other material: BMNH 1977.11.4.8-9 (2 slides) and 

 BMNH 1977.11.11.38. 



Description. With the characters of the genus Nybelinia: The 

 scolex (BMNH 1977-11.4.8-9, Fig. 28B in Southwell, 1929a; 

 BMNH 1977.11.11.38, see Fig. 1) is craspedote with a total length 

 (with velum) of 1701/holotype (1739/paratype). The length of the 

 bothridia is more than half the scolex length, the width at the pars 



Fig. 1 Scolex of Nybelinia southwelli sp. nov. from Nebrius ferrugineus. 

 Scale bar=150 urn. 



bothridialis is 945 (1 134); pbo=1078 (1058), pv=982 (926), pb=485 

 (415), ppb=56 (38), vel=298 (420), BL=474 (404), BW=166 (185), 

 BR=2.9:1 (2.2:1), SP=2.2:2:1 (2.5:2.2: l).The tentacles are long and 

 slender and diminish in size towards the tip; TW basal=46-5 1 (5 1- 

 56), TW metabasal 33-38. A basal tentacular swelling is not present. 

 The tentacle sheaths are sinuous or spirally coiled; TSW 66-70 (5 1- 

 56). Prebulbular organs and muscular rings around the basal part of 

 the tentacle sheaths are absent. The retractor muscles originate in the 

 basal part of the bulbs. 



The armature is homeoacanthous, heteromorphous with a charac- 

 teristic basal armature consisting of 13-14 rows of homeomorphous 

 hooks (Figs 2a, c(i)). The number of hooks per half spiral diminishes 

 towards the apical part of the tentacles: hsr=6 (basal), hsr=4-5 

 (apical). The massive hooks of the metabasal (Figs 2b, c(ii)) and 

 apical (Figs 2b, c(iii)) armature are different in shape and size on 

 bothridial and antibothridial tentacle surfaces. The metabasal ten- 

 tacular armature on the bothridial surface consists of strongly 

 recurved solid hooks with a large base; L=17— 18 (13-15), B=14-16 

 (10-12). On the antibothridial surface, the hooks are more slender 

 and slightly curved with a stout base; L=20-22 (15-18), B=12-14 

 (8-9). The basal armature is homeomorphous, basal hooks with a 

 stout base, a slender shaft, and strongly recurved at the tip (L= 1 8-20 

 (14-16), B=7-8 (6-7)) (Figs 2a, c(i)). The first basal hooks are 

 smaller than those of the remaining basal armature. 



The morphology of the mature and gravid segments of N. 

 southwelli sp. nov. is given in Southwell (1929a, Figs 28E-F), a 

 description and measurements of the proglottids is given in Southwell 

 (1929a, p. 259). The morphology of the strobila and mature and 

 gravid proglottids of BMNH 1 977. 1 1 . 1 1 .38 is given on Figs 3a-c. N. 

 southwelli sp. nov. has a long acraspedote strobila of more than 232 

 proglottids (BMNH 1977.11.4.8-9, strobila not complete), which 





