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Two new species, Cerviniella bisegmenta sp. nov. and C. permixta sp. nov., are described in detail with illustrations based on females from the Korean Yellow Sea. These species lacking the fourth leg endopod belong to the mirabilipes group, one of two species groups within the genus Cerviniella Smirnov, 1946. Both species can be distinguished from each other by the surface ornamentation of the cephalothorax, shape of the rostrum tip, antennule segments, armature formula of thoracic legs 1-4, and length ratio of the caudal rami. Cerviniella bisegmenta sp. nov. is characterized by a short caudal ramus and a two-segmented antennary exopod, which are unique within the genus. Cerviniella permixta sp. nov. differs from other congeners of the mirabilipes group by the seven-segmented antennule, the armature formulae of the exopod of the antenna and thoracic legs 1-4, and the modified apical inner element of the second endopodal segment of the second leg. The present study is the first to identify the genus Cerviniella in Korean waters, resulting in extension of its distribution area to East Asia. [ABSTRACT FROM AUTHOR]

The brackish-water calanoid copepod known as Pseudodiaptomus inopinus in the mainland of Japan consists of two genetically separate species. One is P. japonicus, which was once synonymized with P. inopinus but was recently revived. This paper describes the other species as Pseudodiaptomus yamato n. sp., which is confirmed to have morphological differences from P. inopinus s.s. based on specimens from the type locality (Lake Taihu, China) of the latter. We also redescribe P. japonicus and P. inopinus s.s. for comparative purposes. The three species are distinguishable by the combination of the following morphologies: 1) weak or prominent posterior round projections of the female last pediger; 2) relative length of posterior processes of the female genital operculum; 3) presence or absence of medial spinules on the first exopodal segment of the female leg 5; and 4) the size of spinules at the center of the ventral surface of the male second urosomite. Significant inter-population variation is observed in some spinules of P. japonicus. The past and present records indicate that Pseudodiaptomus yamato n. sp. is endemic to Japan and confined to the coasts affected by the warm Kuroshio Current from western Kyushu to the middle of Honshu, while P. japonicus is widespread in northern East Asia without overlapping the range of P. yamato n. sp. The range of Pseudodiaptomus inopinus s.s. most certainly does not extend to those of P. yamato n. sp. and P. japonicus. [ABSTRACT FROM AUTHOR]