Bull. nat. Hist. Mus. Lond. (Zool.) 66(2): 147-166 



Issued 30 November 2000 



Remarks on the genera Schizocuma Bacescu, 

 1972 and Styloptocuma Bacescu & Muradian, 

 1974 (Crustacea, Cumacea) x^^^oH, 1 



I. PETRESCU 



Department of Invertebrates, 'Grigore Antipa ' National Museum of Natural History, Kiseleffl, Bucharest 

 79744, Romania. 



SYNOPSIS. Morphological data are presented to support the view that Schizocuma Bacescu, 1972 and Styloptocuma Bacescu & 

 Muradian, 1974 are good genera. Both genera exhibited a mixture of characters found in Cumella and Nannastacus, but share 

 more common with Cumella. Schizocuma and Styloptocuma appeared to have evolved in deeper waters, earlier than the rest of 

 Cumella group, having separated from a common stem with the Nannastacus group. 



INTRODUCTION 



Schizocuma Bacescu and Styloptocuma Bacescu & Muradian are 

 two deep-sea genera belonging to the family Nannastacidae. Cur- 

 rently available descriptions of the species in these genera are 

 incomplete, lacking data on the mouthparts or one of the sexes. In 

 the case of Schizocuma vernae, (known only from the holotype), the 

 type material has been lost. Both Schizocuma and Styloptocuma 

 have been subjects of systematic revisions by authors who have 

 either totally or partially invalidated them (Jones 1984, Watling 

 1991), or considered them to be good genera (Bacescu 1992, Holt- 

 huis 1990). 



This study is based entirely on material loaned to the author by the 

 Department of Zoology of the Natural History Museum, London. 



Cumella formosa Jones, 1984 1992:676:4 



3 females, 1 immature male, 1 manca; collecting data - Atlantis II 



60, sta. 245, 36° 55.7' S 53° 61.4' W, 2707 m, 14.3.1971. 



Cumella spinoculata Jones, 1984 1992:783:7 



3 females, 2 males and 2 juv.; collecting data -Chain 106, sta. 313, 



51° 32.2' N 12° 35.9' W, 1500 m. 17.8.1972. 



Cumella vernae (Bacescu & Muradian, 1974) 1992:777:4 



1 female, 2 immature males; collecting data-Atlantis II 31, sta. 167, 



7° 58' S 34° 17' W, 1007 m, 20.2.1967. 



13 specimens in glycerine-alcohol on slides were dissected for 

 this study. Measurements were taken with an ocular micrometer, and 

 all the slides are deposited in the collections of the Natural History 

 Museum, London. 



MATERIALS AND METHODS 



SYSTEMATIC REMARKS 



The material examined consists of non type specimens of 8 species, 

 7 of which were described by Jones (1984); all were previously 

 identified by him and included in the genus Cumella. These speci- 

 mens were collected by different research vessels of Woods Hole 

 Oceanographic Institute. 



Cumella acuminatum Jones, 1984 1992:700:30 



86 specimens (females and immature males); collecting data - 



Atlantis II 31, sta.156, 0° 46' S 29° 28' W, 3459 m, 14.2.1967. 



Cumella antipai (Bacescu & Muradian, 1974) 1992:678:10 



13 females, 3 males (2 adults and 1 immature); collecting data - 



Knorr 25, sta.293, 8° 58' N 50° 04.3' W, 1518 m, 27.2.1972. 



Cumella bishopi Jones, 1984 1992:677:30 



44 females, 38 males (22 adults and 16 immatures); collecting data 



- Knorr 25, sta.293, 8° 58' N 50° 04.3' W, 1 5 1 8 m, 27.2. 1 972. 



Cumella dayae Jones, 1984 1992:684:36 



22 females, 17 males (5 adults and 12 immatures); collecting data - 



Atlantis II 60, sta. 245, 36° 35.7' S 53° 01' W, 2707 m, 14.3.1971. 



Cumella echinata Jones, 1984 1992:685:20 



18 females, 4 males; collecting data -Chain 106, sta. 313, 5 1° 32.2' 



N 12° 35.9' W, 1500 m, 17.8.1972. 



Genus SCHIZOCUMA Bacescu, 1972 



Schizocuma Bacescu, 1972: 246. 

 Cumella Jones, 1984: 210-211. 

 Schizocuma Watling, 1991: 755. 

 Schizocuma Bacescu, 1992: 258-259. 



Type species. Schizocuma vernae Bacescu, 1972. 



DIAGNOSIS. Carapace short (one-fifth the length of pleon with 

 uropods), without carinae, with long hairs in males and dorsal spines 

 in females (also on the ocular lobe); antero-ventral corner rounded 

 or subacute, antero- inferior edge slightly serrated. Median ocular 

 lobe incompletely subdivided. Branchial siphons separated, located 

 medially to dorsolaterally; pseudorostral lobes widely separated. 

 Pleonites long and thin, their length increasing distally up to the 

 fifth, which is 5.5 times longer than broad. Pleotelson short. An- 

 tenna 1 without tubercle on 2 nd article of peduncle, subequal in 

 length or longer than 3 rd , accessory flagellum 2-articulated. Antenna 

 2 with short flagellum. Pars incisiva of mandible with 4 teeth, lacinia 

 mobilis, thin, with 3 teeth, not exceeding pars incisiva, five long 

 plumose lifting setae between lacinia mobilis and truncated, robust, 

 pars molaris. Maxilla 1 with simple robust acuminate setae on 



© The Natural History Museum, 2000 



