SYSTEMATIC ACCOUNT 

 FAMILY TUCCIDAE VERVOORT, 1962 



Diagnosis 



Female. — Metamorphosed cyclopoid. Body 

 composed of head, neck, trunk, and "tail." Head 

 formed by fusion of cephalosome and first 

 pedigerous segment, globular doraally, flattened 

 and hollowed ventrally, and winged laterally. 

 Cephalic appendages and first leg housed in 

 ventral concavity. Neck short, wider than long, 

 formed by second pedigerous segment, dis- 

 tinctly separated from trunk posteriorly. Trunk 

 composed of fused third and fourth pedigerous 

 segments, inflated, much wider than head and 

 neck. "Tail" composed of transformed urosome 

 with all segments completely fused, flattened, 

 wider than long, attached posteroventrally to 

 trunk. Caudal rami small. Eggs multiserate; 

 egg sacs elongate, cylindrical. 



First ant€nna 5 or 6 segmented, with nu- 

 merous setae. Second antenna 3-segmented; 

 terminal segment armed, in addition to claws 

 and setae, with pectinate, lamelliform process 

 at tip and several rows of teeth or scales over 

 posterior surface. Labrum with marginal teeth ; 

 labium weakly developed. Mandible elongate, 

 with two denticulated spines. Paragnath pres- 

 ent. First maxilla a small, rounded protrusion, 

 bearing four setae. Second maxilla 2-seg- 

 mented, tipped with three denticulated spines. 

 Maxilliped indistinctly 3-segmented, terminal 

 segment strongly bent and pointed. Four pairs 

 of biramous legs ; rami with reduced segments. 

 Leg five, 1-segmented, segment very small, 

 tipped with three setae. Leg 6 absent. 



Male. — Unknown. 



Remarks 



This family contains but a single genus, 

 Tucca Kr0yer, 1837. The genus Tuccopsis 

 Pearse, 1952, which was included in the family 

 by Yamaguti (1963), is synonymous with Blias 

 Kniyer, 1864, of the family Chondracanthidae. 

 This synonymy was first pointed out by Causey 

 (1955: 7) and followed by Vervoort (1962: 

 93). 



When Vervoort (1962) reviewed the family 

 Bomolochidae, he included the genus Tucca, fol- 

 lowing Wilson's (1911) opinion, but he set the 



genus in a new subfamily Tuccinae. Since Ver- 

 voort did not himself examine specimens of the 

 genus Tucca, his accounts on the Tuccinae Ver- 

 voort, Tucca Kr0yer, T. impressus Kr0yer, T. 

 corpulentus Wilson, and T. verrucosus Wilson 

 were wholly based on Wilson's inaccurate ob- 

 servations (see Remarks in the following two 

 sections). Yamaguti's (1963) account was also 

 based entirely on Wilson's descriptions. There- 

 fore, neither the diagnosis of the family Tucci- 

 dae given by Yamaguti (1963: 42) nor the 

 diagnosis of the subfamily Tuccinae given by 

 Vervoort (1962: 92) can be adopted here. The 

 status of the family is then : a redefined family 

 Tuccidae Yamaguti, 1963, embracing within it 

 the redefined and promoted subfamily Tuccinae 

 Vervoort, 1962. 



Wilson (1911: 353) pointed out that the 

 copepods of the genus Tucca are closely related 

 to the bomolochid copepods, a relation.ship 

 especially suggested by the mouth parts and 

 other cephalic appendages. I consider the fol- 

 lowing characteristics of the female of the 

 genus Tucca, however, so different from those 

 of the bomolochids that Tucca should be placed 

 in a different family: 



1. The female undergoes metamorphosis 

 after the last copepodid stage. All known 

 bomolochids (this means all the copepods at- 

 tributed to the subfamily Bomolochinae by 

 Vervoort in 1962) have no metamorphosis, and 

 all have a cyclopoid form of body. In the tuc- 

 cids, however, a metamorphosed adult female 

 has its body distinctly separated into head, 

 neck, and "tail ;" the appearance is not at all 

 cyclopoid. 



2. The urosome of the female is rudimentary, 

 its length less than one tenth of the body. The 

 urosome of the bomolochids is always at least 

 one third as long as the body and distinctly 

 5-segmented ; it comprises a fifth pedigerous 

 segment, a genital segment, and three post- 

 genital segments. Tuccids have a rudimentary 

 fifth pedigerous segment, a genital segment, 

 and a single po.stgenital segment, all fused into 

 one unit and unsegmented. 



3. The fifth leg is very rudimentary, merely 

 a small, single segment armed with three .setae. 

 The fifth leg of a typical bomolochid is 2-.seg- 

 mented and consists of a small intermediate 



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U.S. FISH AND WILDLIFE SERVICE 



