Miscellanea Zoologica Hungarica 11. 1997 (Budapest, 1997)

Hołyńska, M.: A new representative of Mesocyclops thermocyclopoides-circle (Copepoda: Cyclopoida) from India

Nevertheless, the similarities in the spinule armature of the furcal rami and the caudal surface of leg 4 coxa (spinules at implantation of the posterolateral furcal setae; several spinules in more than one row near the proximal rim, and also relatively many spinules near the distal rim of leg 4 coxa) suggest M. dussarti Van de Velde, 1984 to be the closest relative of M. dadayi sp. n. M. isabellae Dussart & Fernando, 1988 and M. thermocyclopoides Harada, 1931 have no teeth at base of the posterolateral furcal setae, the caudal surface of leg 4 coxa bears one spinule row near the proximal rim and few spinules along distal rim (Fig. 4F, H). Alternates of the three above mentioned characters occur both in, and outside of the Thermocyclopoides-ciicle, which does not support in their case unambiguous polarizations.The character distribution within the species quartette and proposed scheme of the phylogenetic relationships are shown in Table 4 and Fig. 5. M. dussarti M. dadayi M. isabellae Af. thermocyclopoides III I West-Africa India (Calcutta) India, Sri Lanka Southeast-Asia Fig. 5. Hypothetic phylogenetic relationships of M. dadayi sp. n., and distribution of the closely related species. (Characters used in the phylogenetic reconstruction see in Table 4.) Table 4. Distribution of characters choosed to resolve phyl ogenetic relationships of M. dadayi sp. n. 1 2 3 4 5 M. dadayi sp. n. + + + + + + M. dussarti Van de Velde, 1984 + + + + ± + M. isabellae Dussart et Fernando, 1988 + + + - M. thermocyclopoides Harada, 1931 + + _ 1 = Irregular hairs on dorsum of pediger 5 2 = Dorsal hairs on proximal half of the genital double somite 3 = Spinule rows on 14. antennular segment 4 = Spinules at implantation of posterolateral furcal setae 5 = Many (>9) spinules near distal rim on caudal surface of the leg 4 coxa. 6 = More than one spinule row near proximal rim on caudal surface of the leg 4 coxa. + = presence [1-4]; many spinules [5]; more than one row [6] - = absence [3,4]; few (at most 9) spinules[5]; one spinule row [6] ± = many, or few spinules