Bull. nat. Hist. Mus. Lond. (Zool.) 60(2): 105-172 



Issued 24 November 1994 



Phylogenetic relationships between arietellid 

 genera (Copepoda: Calanoida), with the 

 establishment of three new genera 



S. OHTSUKA 



Fisheries Laboratory, Hiroshima University, 1294 Takehara, Hiroshima 725, Japan 



G.A. BOXSHALL 



Department of Zoology, The Natural History Museum, Cromwell Road, London SW7 5 BD, England 



H.S.J. ROE 



Institute of Oceanographic Sciences Deacon Laboratory, Brook Road, Wormley, Godalming, Surrey 

 GU8 5UB, England 



CONTENTS 



Materials and Methods 



Arietellidae Sars, 1902 



Crassarietellus gen . nov 



Campaneria gen. nov 



Paraugaptiloid.es gen. nov 



Arietellus Giesbrecht, 1892 .... 

 Rhapidophorus Edwards, 1891 

 Paramisophria T. Scott, 1897 . 

 Metacalanus Cleve, 1901 



HiSTORYMiSrUM 



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ZOOLOGY LIBRARY | 



108 



108 



109 



119 



120 



126 



131 



135 



138 



Paraugaptilus Wolfenden, 1904 143 



Scutogerutus Bradford, 1969 152 



Sarsarietellus Campaner, 1984 155 



Pilarella Alvarez, 1985 156 



Discussion 158 



Acknowledgements 171 



References 171 



Synopsis. Ten genera, including three new genera, Crassarietellus, Campaneria and Paraugaptiloides, of the family 

 Arietellidae (Copepoda: Calanoida) are newly defined or redefined with special reference to the genital systems of 

 the females and fusion patterns and armature elements of appendages. The present study revealed that the single 

 specimen reported as the male of Sarsarietellus abyssalis (Sars, 1905) represents a new genus, Crassarietellus, and 

 that Paraugaptilus mohri Bjornberg, 1975 belongs to the genus Arietellus. Ancestral and derived states and character 

 transformations of the genital systems and the appendages in the family are discussed. A cladistic analysis for all 10 

 genera except for Rhapidophorus revealed that the Arietellidae consists of two lineages, the Crassarietellus- 

 Paramisophria-Pilarella-Metacalanus-gTOup and the Cumpaneria-Sarsarietellus-Paraugaptiloides-Scutogerulus-Par- 

 augaptilus-Arietellus-group. The deep-sea hyperbenthic genera Crassarietellus and Campaneria are the most 

 plesiomorphic in each group, and the shallow-water hyperbenthic/epipelagic/cave-living Metacalanus and the 

 bathypelagic v4/"zefe//!« and Paraugaptilus are relatively apomorphic. 



INTRODUCTION 



The family Arietellidae Sars, 1902 has been regarded as one of 

 the most primitive families in the Calanoida based on the 

 segmentation of appendages and the genital systems (Andronov, 

 1974; Park, 1986; Huys & Boxshall, 1991). The Arietellidae had 

 hitherto accommodated the following eight genera: Rhapi- 



dophorus Edwards, 1891, Arietellus Giesbrecht, 1892, Parami- 

 sophria T. Scott, 1897 (= Parapseudocyclops Campaner, 1977), 

 Metacalanus Cleve, 1901 (= Scottula Sars, 1902), Paraugaptilus 

 Wolfenden, 1904, Scutogerulus Bradford, 1969, Sarsarietellus 

 Campaner, 1984, and Pilarella Alvarez, 1985. The genus Phyllo- 

 pus Brady, 1883 was separated by Brodsky ( 1950) who proposed 

 placing it in a new subfamily; it was later removed from the 

 Arietellidae and placed in its own family, the Phyllopodidae 



)Thc Natural History Museum, 1994 



