Bull. not. Hist. Mus. Loud. (Zool.) 65(2): 123-131 



Issued 25 November 1999 



Nybelinia southwelli sp. nov. (Cestoda, 

 Trypanorhyncha) with the re-description of N. 

 perideraeus (Shipley & Hornell, 1906) and 

 synonymy of N. herdmani (Shipley & Hornell, 

 1906) with Kotorella pronosoma (Stossich, 

 1901) 



HARRY W. PALM 



Marine Pathology Group, Department of Fisheries Biology, Institut fur Meereskunde an der Universitat Kiel, 

 Dusternhrooker Weg 20, D 24105 Kiel, Germany 



THORSTEN WALTER 



Marine Pathology Group, Department of Fisheries Biology, Institut fiir Meereskunde an der Universitat Kiel, 

 Dusternhrooker Weg 20, D 24105 Kiel, Germany 



SYNOPSIS. During a study of Nybelinia material deposited at The Natural History Museum, London, Nybelinia southwelli sp. 

 nov. was discovered amongst material identified and described as Tetrarhynchus perideraeus Shipley & Hornell, 1906 from 

 Rhina ancylostoma and Nebriusfemtgineus from Sri Lanka. The new species belongs to the subgroup IIBa of Palm et al. ( 1 997). 

 which includes species having a homeoacanthous heteromorphous metabasal armature and a characteristic basal armature where 

 the basal hooks are smaller or equal in size to the metabasal hooks. It can easily be distinguished from all other members of this 

 group by having characteristic rose-thorn shaped metabasal and slender basal hooks. The type material of Nybelinia perideraeus 

 (Shipley & Hornell, 1906) was borrowed from the Natural History Museum, Vienna, for comparison, and is re-described. N. 

 dakari Dollfus, 1960 is considered synonymous with N. perideraeus. Nybelinia herdmani (Shipley & Hornell. 1906). also placed 

 in the subgroup IIBa by Palm et al. (1997), is considered synonymous with Kotorella pronosoma (Stossich, 1901) Euzet & 

 Radujkovic, 1989. The subgroupings of Nybelinia species based on the species specific tentacular armature appear to be useful 

 for further taxonomic studies within the genus. 



INTRODUCTION 



Trypanorhynch cestodes are common parasites of marine 

 elasmobranchs, where they mature in the stomach or the spiral 

 valve. The plerocercoids are parasitic in many teleosts and a variety 

 of invertebrates while the first intermediate hosts are crustaceans. 

 Among trypanorhynch cestodes, Nybelinia Poche, 1926 is the larg- 

 est genus. Palm et al. (1997) listed 43 adequately described species 

 while leaving 4 species of uncertain status, and Jones & Beveridge 

 (1998) added N. queenslandensis. Vijayalakshmi et al. (1996) de- 

 scribed Tentacularia scoliodoni on the basis of the tentacular 

 armature, not considering the most recent generic definitions of 

 Tentacularia and Nybelinia in the key of Campbell & Beveridge 

 ( 1994). The species strongly resembles N. indica Chandra, 1986 and 

 N. africana Dollfus, 1960, and should be treated as species of 

 uncertain status pending on examination of further material. Thus, 

 with a total of 44 adequately described species, the genus Nybelinia 

 currently comprises the most species-rich genus within the order 

 Trypanorhyncha. 



One of the biggest problems for taxonomic work within the 

 genus, apart from poor original descriptions, remains the lack of 

 information on material available in museum collections for com- 

 parative morphological studies. Many species have a similar scolex 

 morphology and tentacular armature. Additionally, several species 

 descriptions are based on single specimens and data on intraspecific 



variability are scarce. Studies of Nybelinia deposited in collections 

 are needed to determine validity as well as for re-descriptions. 



During a study on Nybelinia material deposited at the British 

 Museum, Natural History, slides labelled and described as 

 Tetrarhynchus perideraeus Shipley & Hornell, 1906 from the T. 

 Southwell collection (Southwell, 1929a, p. 257-259) appeared to 

 bear a species different to that indicated. The present study was 

 carried out to clarify the identity of this material. The type material 

 of Nybelinia perideraeus was borrowed from the Natural History 

 Museum, Vienna, for comparison, and re-description. Beside this, 

 the taxonomic position of N. herdmani (Shipley & Hornell, 1906) is 

 clarified. 



MATERIAL AND METHODS 



Standard measurements and drawings of the scoleces of Nybelinia 

 specimens deposited in the Parasitic Worms Division, The Natural 

 History Museum London (BMNH), were made using a Leitz Wetzlar 

 Dialux 20 microscope with an ocular micrometer. The type speci- 

 mens of Nybelinia perideraeus and N. herdmani were borrowed 

 from the collection of the Naturhistorisches Museum Wien ( VNHM) 

 and examined with a Leitz Wetzlar Orthoplan microscope. Draw- 

 ings were made using a Leitz Wetzlar Dialux 22 microscope with a 

 drawing tube. 



© The Natural History Museum, 1999 



