Two new species belonging to the dentipes- and conifera-subgroups of Triconia (Copepoda: Cyclopoida: Oncaeidae) from the East China Sea

Abstract

Two new species of Triconia in Oncaeidae, including both sexes of Triconia constricta n. sp. and females of Triconia pararedacta n. sp., are described from south of Jeju Island in the East China Sea. Triconia constricta belongs to the dentipes-subgroup of Triconia characterized by the absence of integumental pockets on the anterior surface of the labrum. It is distinguished from the closely related species of this subgroup, T dentipes (Giesbrecht, 1891), T elongata Bottger-Schnack, 1999, and T giesbrechti Bottger-Schnack, 1999, by the following combination of morphological features in females: 1) lateral margins of genital double-somite in dorsal view slightly constricted at midlength; 2) P5 with very long outer basal seta, reaching beyond paired secretory pores on posterior part of genital doublesomite, as well as distinctive length ratios of exopodal setae; in both sexes; 3) length ratios of caudal setae, and 4) relative spine lengths on distal endopodal segments of swimming legs 2 to 4. Triconia pararedacta is a member of the conifera-subgroup characterized by a dorsal projection on the second pedigerous somite in the female. It differs from females of other species of this subgroup in the following: 1) very small-sized dorsal projection on second pedigerous somite, 2) different length to width ratio of P5 exopod, 3) relative lengths of outer basal seta and exopodal setae of P5, and 4) different length ratio of outer distal spine to distal spine on endopods of P2-P4. Additional character states are proposed for defining the dentipes-subgroup within Triconia and for recognizing three sets of species within the conifera-subgroup.