CYCLOPOID COPEPODS OF THE GENUS TUCCA (TUCCIDAE), 

 PARASITIC ON DIODONTID AND TETRAODONTID FISHES 



By Ju-shey Ho, B.Sc, M.A. 

 Department of Biology, Boston University, Boston, Massachusetts 02215 



ABSTRACT 



The female of Tucca impressus KrjJyer is redescribed, on 

 the basis of specimens taken from Chilomycterus schoepfi 

 (Walbaum) in the Gulf of Mexico. Both genus Tucca 

 Kr(jyer and family Tuccidae Vervoort are redefined, and 

 the genus is treated as monotypic. A restudy of the speci- 

 mens in the U.S. National Museum revealed that T. 

 corpulentus Wilson should be synonymized with T. im- 

 pressus and that the males of T. impressus described by 

 Wilson (1911) are actually some immature adult females 

 of the same species before complete metamorphosis. 



Metamorphosis occurs only in the cephalothorax and 

 the last two segments of the metasome; the second pedig- 

 erous segment and the urosome remain unchanged. The 



metamorphosis is widening rather than lengthening in the 

 head, but more lengthening than widening in the trunk. 



Some geographical variation in size and shape is ob- 

 served in the metamorphosed parts of the body. The three 

 recognized geographical types are: Atlantic type (with 

 slightly bilobed lateral wings of head and less prominent 

 posterior lobes in trunk). Gulf type (with unlobed lateral 

 wings of head and less prominent posterior lobes in trunk), 

 and Caribbean type (with prominent bilobed lateral wings 

 of head and posterior lobes in trunk). This variation is 

 not strictly expressed, however, by every individual in a 

 given geographical range. 



This study was developed from the identifica- 

 tion of two specimens of immature adult fe- 

 males of Tucca impressus Kr0yer, which were 

 collected from the caudal fin of a spiny boxfish, 

 Chilomycterus schoepfi (Walbaum), at Alliga- 

 tor Harbor, Fla. The specimens were collected by 

 Jack Rudloe and sent to William A. Newman, 

 Museum of Comparative Zoology, Harvard Uni- 

 versity, for identification, and subsequently 

 were passed to me through Arthur G. Humes, 

 Department of Biology, Boston University, in 

 May 1965. Because my observations on these 

 two parasites were so different from the de- 

 scription by Wilson (1911), five more collec- 

 tions were obtained and studied. In addition, I 

 reexamined the specimens in the USNM (U. S. 

 National Museum) which were studied by Wil- 

 son. This reexamination revealed that Wilson 

 (1911) had introduced errors into our knowl- 

 edge of the species of the genus Tucca Kr0yer. 

 The later establishment of a subfamily (by 

 Vervoort, 1962) and family (by Yamaguti, 

 1963) to contain Tucca is based on the in- 

 formation supplied by Wilson. 



FISHERY BULLETIN: VOLUME 66, NO. 2 

 Published May 1967. 



A redescription of the species and redefini- 

 tion of the genus and the family are given here. 

 Observations on metamorphosis and geograph- 

 ical variation in morphology are also included. 



The redescription of the female of T. impres- 

 sus given below is mainly based on specimens 

 collected off Cape San Bias, in the Gulf of 

 Mexico, because this collection is the largest of 

 my collections, contains numerous females in 

 various stages of growth, and indicates a cer- 

 tain pattern of metamorphosis. The data given 

 in tables 2, 3, and 4 were prepared from this 

 collection to aid in the explanation of meta- 

 morphosis. 



After the discovery of a certain degree of 

 geographical variation of T. impressus, tables 

 5 and 6 were prepared from the two largest col- 

 lections in the USNM, one from North Carolina 

 and the other from Jamaica. Table 4 gives 

 data on the specimens taken from the Gulf of 

 Mexico, which also helps to explain geograph- 

 ical variation. 



The specimens were dissected and examined 

 in lactic acid, and the figures were drawn with 

 the aid of a camera lucida. 



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