Tapholeon chappuisius ( Krishnaswamy, 1957 ) Gheerardyn & Fiers & Vincx & Troch, 2007

Gheerardyn, Hendrik, Fiers, Frank, Vincx, Magda & Troch, Marleen De, 2007, Revision of the genus Tapholeon Wells, 1967 (Copepoda, Harpacticoida, Laophontidae), Journal of Natural History 41 (37 - 40), pp. 2479-2510 : 2493-2494

Tapholeon chappuisius ( Krishnaswamy, 1957) comb. nov.

Synonym. Asellopsis chappuisius Krishnaswamy, 1957 .

Type locality

India, Madras: Mandapam, sandy beach ( Krishnaswamy 1957).

Type material

Unknown.

Diagnosis

Body strongly tapering towards caudal rami. Caudal rami slightly longer than wide. Antennule five-segmented. Antennary exopod well developed bearing three (?) setae. P1 with two-segmented exopod; exp-2 bearing three (?) setae. Exp-2 of P2–P4 with inner seta. Exp-3 of P2 with one inner seta and two outer spines; exp-3 of P3 and P4 each with two inner setae and two outer spines. Enp-2 of P2–P4 with only two apical setae each. Female P5 with four baseoendopodal and five exopodal setae. Baseoendopod reaching almost to distal margin of exopod. Exopod ovate, about two times as long as wide. Male swimming legs P1–P4 as in female. Endopodal lobe of male P5 without seta. Exopod small; bearing four setae.

Length of female: 1.2 mm ( Krishnaswamy 1957), 0.56 mm ( Rao and Ganapati 1969). Length of male: 0.9–1 mm ( Krishnaswamy 1957).

Remarks

For the same reason as mentioned for T. arenicolus ( Chappuis, 1954) comb. nov., Krishnaswamy (1957) assigned this species to the genus Asellopsis Brady and Robertson, 1873 . However, A. chappuisius must be allocated to the genus Tapholeon because of the lack of sexual dimorphic structures in the swimming legs. The presence of an armed, strong spine on the second segment of A1 might have been overlooked. The lack of type material, however, prevented verifying this.

Several comments on the species description by Krishnaswamy (1957) are necessary. The antennule is described as being five-segmented. The faint suture, separating segment four and five (as seen in the type species), might have been missed and, therefore, the antennule might be six-segmented. The drawing of the exopod of the antenna shows only three setae. In the species of the genus Tapholeon , one seta of the antennary exopod is very slender and small, and can easily be overlooked. A much more important problem arises in the enumeration of the legs. The figure of the P4 ( Krishnaswamy 1957) undoubtedly illustrates the P2 of this species. P4 has two inner setae on the last exopodal segment in the majority of the species and never has an endopod reaching to the apical edge of the second exopodal segment. Consequently, the figure of P2 must be another leg and seems to represent P3 because: (1) the third exopodal segment bears two inner setae and (2) the endopod reaches to the middle of the second exopodal segment. The description of P2 has to be considered as the description of the P4. This amendment results in an entirely different setal formula as given in Table I.

Most curiously, Rao and Ganapati (1969) follow Krishnaswamy (1957) in their redescription of T. chappuisius . However, the drawings given by Rao and Ganapati (1969, Figure 16) appear to be duplicates from the original ones.

Differential diagnosis

T. chappuisius comb. nov. bears two outer spines on the ultimate segments of the exopods of P2–P4 and only bears two apical setae on the second endopodal segments of P2–P4.

Distribution

Madras ( Krishnaswamy 1957) and Waltair ( Rao and Ganapati 1969), both in the Bay of Bengal.