북동태평양 클라리온 클리퍼톤 해역에서 Oncaeidae 과의 분류학적 연구

Abstract

This study aims to give a detailed morphological description including microstructure of the mouthparts and the exoskeleton (such as integumental structures) of the family Oncaeidae collected from the CCFZ in the Pacific Ocean (the northeast equatorial Pacific area). Oncaids copepod were collected from 100 m depth to the surface with a conical net (60 ㎝ mouth diameter, 60 ㎛ mesh size) at Station KOMO (KORDI Long-term Monitoring Station) (10°30'N, 131°20'W) in the KODOS (Korea Deep Ocean Study) area, located at the CCFZ (Clarion -Clipperton Fracture Zone; C-C zone) in the southeastern part of the northeast equatorial Pacific during August 2009. According to the phylogenetic analysis by Bö ttger-Schnack and Huys (1998), twenty four species of Oncaeidae are classified into 11 distinct subgroups in the northeast equatorial Pacific. Eleven species consisted of Oncaea: venusta-/ clevei-/ ovalis-/ notopus-/ tregoubovi-/ atlantica-subgroups. The genus Triconia has 11 species, which belong to the conifera-, similis-, and the dentipes-subgroups, as defined by Bö ttger-Schnack and Huys. Spinonacaea and Monothula one species, respectively. These species, except for atlantica-subgroup, can readily be grouped into seven types by the ornamentation of the labrum: (1) the number of chitinized teeth at medial concavity on posterior surface of labrum; (2) the absent or present of integumental pockets on the anterior; (3) the number of elements on ventral margin of the lobe. Thus the mouthparts, especially in larbum structure assist the great importance in the taxonomy and phylogeny of oncaeid copepods. Except for venusta- and clevei-subgroups, it is possible to place the species of the several groups into new genera by their morphological characteristics, particularly the species of the notopus- and atlantica-subgroups. O. prolata has the presence of a very short seta on the inner corner of the coxa. This characteristic was first found from this study area in O. prolata. If all species of the notopus-subgroup belonging to O. prolata have this seta, this group casubgroupn be separated from all other species or genera. Therefore, descriptions for other species of the notopus-subgroup need to be studied in more detail in the future The atlantica-subgroup has unique leg armature, which separates them from most other oncaeid species (or subgroups); such as (1) the absence of an outer subdistal spine on P2-P4 exp-3 (arrowed in Fig. 34B-D), (2) the absence of long setules on the inner margin of proximal exopod segments in P1-P4, (3) hyaline lamellae on outer exopodal spines narrow or naked, (4) the produced terminal conical process with apical pore on the distal endopod segments of P2-P4, and (5) the inner subdistal element setiform instead of spiniform on P2-P4 enp-3. As the above mentioned characteristics, it is also possible to place the species of the atlantica-subgroup into a new genus. Through this study, the presence of O. parabatyalis and T. hirsuta has now been verified in the Pacific Ocean. Thus, there is a wide the geographical distribution of this species in tropical and warm-temperate regions of the Ocean. The detailed information of morphology of the family Oncaeidae in this study will help to study for various biological aspects, including ecological taxonomic, and phylogenetic parameters.