Taxonomical studies on corycaeids and oncaeids (Copepoda: Cyclopoida) in the northern East China Sea and their characteristics on occurrence related to water mass

위진희,서호영 한국해양환경·에너지학회 2012 한국해양환경공학회 학술대회논문집 Vol.2012 No.5

Two Species of the Genus Oncaea (Copepoda, Poecilostomatoida, Oncaeidae) from the East Sea, Korea

위진희,서해립,양한섭,서호영 한국해양과학기술원 2008 Ocean science journal Vol.43 No.4

Oncaea venusta Philippi, 1843 has been known as having some different size groups, but recent genetic study for cyt b and ITS 1 (Elvers et al. 2006) suggests that these size groups can be considered as different species. Of these size groups, the largest O. venusta Philippi and the smallest O. venella Farran, 1929 were first described in Korean waters. The latter is easily distinguishable from the former in the following characteristics in addition to its small size: (1) length to width ratio of genital double somite of two genders smaller, and (2) female second pediger bearing inconspicuous dorso-posterior swelling. Oncaea venusta and O. venella co-occur in Korean waters during spring to fall, but their occurrence patterns seasonally differ: the former shows higher density in fall while the latter does in summer. Oncaea venusta Philippi, 1843 has been known as having some different size groups, but recent genetic study for cyt b and ITS 1 (Elvers et al. 2006) suggests that these size groups can be considered as different species. Of these size groups, the largest O. venusta Philippi and the smallest O. venella Farran, 1929 were first described in Korean waters. The latter is easily distinguishable from the former in the following characteristics in addition to its small size: (1) length to width ratio of genital double somite of two genders smaller, and (2) female second pediger bearing inconspicuous dorso-posterior swelling. Oncaea venusta and O. venella co-occur in Korean waters during spring to fall, but their occurrence patterns seasonally differ: the former shows higher density in fall while the latter does in summer.

Re-evaluation of Morphological Diagnostic Characteristics of Hexapleomera Dudich, 1931 (Crustacea: Tanaidacea), with Description of a New Species

위진희,강창근,이인태,정현경 한국해양과학기술원 2018 Ocean science journal Vol.53 No.4

An undescribed species of Tanaidacea was collected from Yokji Harbor in the southern coast of Korea. Hexapleomera yokjidona n. sp. can be distinguished from other species of the genus by the distinguishing features of a uropod with five articles, a pleopod basal article lacking inner seta, a mandible setal row with two setae, maxilliped coxa with two proximal setae, pereonites 1?3 together longer than wide, and pereopods 2?3 propodus with three ventral setae. To prove that H. yokjidona is a new species, detailed morphological characteristics of both genders are described and a comprehensive comparison among the species of the genus is tabulated. Additionally, diagnostic characteristics previously used to identify the species of Hexapleomera are reassessed and upgraded.

Taxonomical studies on corycaeids and oncaeids (Copepoda: Cyclopoida) in the northern East ChinaSea and their characteristics on occurrence related to water mass

위진희,서호영 대한조선학회 2012 대한조선학회 학술대회자료집 Vol.2012 No.5

A New Species of Farranula (Copepoda: Cyclopoida: Corycaeidae) from the West Central Pacific, with a Key to Species of the Genus

위진희,서호영,정현경,강형구 한국동물분류학회 2015 Animal Systematics, Evolution and Diversity Vol.31 No.1

A new species of the genus Farranula Wilson, 1942 (Cyclopoida, Corycaeidae) is described based on bothsexes collected off Chuuk Island in Micronesia (West Central Pacific). The new species F. dahlae differsfrom its close congener F. gibbula (Giesbrecht, 1891) in the following combination of characters in bothsexes: body length is longer, length to width ratio of caudal rami is larger, basal element of maxilliped isdistinctly longer, and terminal spine to distal segment ratio of P4 is smaller; while in females, lateral marginsof fourth pedigerous somite are extended to mid-region of second urosomal somite, maximum width of thesecond urosomal somite is located at middle region in dorsal and lateral views, and length ratio of caudal setaIII to seta V is much larger; and in males, sharply contracted portion of second somite is located at two-thirdsdistance from anterior margin. Some additional morphological details of F. gibbula are given and a key tospecies of the genus Farranula is provided.

Five Oncaea Species (Copepoda, Poecilostomatoida, Oncaeidae) from the Korean Waters, with Notes on the Spatio-temporal Distribution of Korean Oncaeid Species

위진희,윤양호,서호영 한국해양과학기술원 2009 Ocean science journal Vol.44 No.2

Five Oncaea species were recorded on the basis of specimens collected using three type nets from the South Sea and the East Sea of Korea. These included the clevei-group of one species (O. clevei) and the venusta-group of four species (O. media, O. mediterranea, O. scottodicarloi, O. waldemari). The former has a dorsoposterior projection on the second pedigerous somite, while the latter do not bear any dorsal projection on the somite. Also, their spatio-temporal distribution are discussed in relation to temperature-salinity. Five Oncaea species were recorded on the basis of specimens collected using three type nets from the South Sea and the East Sea of Korea. These included the clevei-group of one species (O. clevei) and the venusta-group of four species (O. media, O. mediterranea, O. scottodicarloi, O. waldemari). The former has a dorsoposterior projection on the second pedigerous somite, while the latter do not bear any dorsal projection on the somite. Also, their spatio-temporal distribution are discussed in relation to temperature-salinity.

Three species of Agetus (Copepoda, Cyclopoida, Corycaeidae) New to Korean Taxa

위진희,김대환,서호영 한국해양과학기술원 2013 Ocean science journal Vol.48 No.4

The genus Agetus (Cyclopoida, Corycaeidae) has so far been identified by insufficient taxonomic information due to lack of morphological details such as mouthparts, spine lengths of each leg, ornamentation on surface of second urosomal somite. These features are considered as important morphological characteristics in classifying small cyclopoid copepods through taxonomic studies. In this study, some distinct and minute morphological characteristics are used to separate each species within Agetus, with the first redescription of A. typicus, A. flaccus, and A. limbatus from Korean waters. All three species are carefully well redescribed and comparisons with past records from other localities are provided. The zoogeographical distribution has also been summarized.

Three Species of Ditrichocorycaeus (Copepoda, Cyclopoida, Corycaeidae) from Korean Waters, with New Identification Parameters

위진희,김대환,서호영 한국해양과학기술원 2013 Ocean science journal Vol.48 No.4

Three species of Ditrichocorycaeus [D. dahli (Tanaka, 1957), D. lubbocki (Giesbrecht, 1981), and D. subtilis (Dahl, 1912)] are first redescribed from southern area of Jeju Island, Korea. Morphological details such as mouthparts, ornamentation of genital double-somite, spine lengths of legs, and proportional lengths of caudal setae, are provided as new identification keys separating each species within Ditrichocorycaeus and/or each genus within Corycaeidae. In particular, the number and location of each segment on the body and antenna are re-examined and precisely defined. Also, few valid morphological characters of this genus distinguishing it from other genera are newly proposed as follows: 1) prosomes of both sexes are five-segmented; 2) basis of maxilliped with relatively longer proximal seta than in other genera.

Two New Species of Leptochelia (Crustacea, Tanaidacea) from the West Coast of Korea

위진희,정만기,정현경,박광재 한국동물분류학회 2015 Animal Systematics, Evolution and Diversity Vol.31 No.4

Two new species of Leptochelia Dana, 1849 are described from the western coast of Korea. Leptochelia grandidentata n. sp. is similar to L. itoi and L. lusei characterized by pleonites 4 and 5 of subequal lengths and a uropod endopod with 4 articles but differentiated by a cheliped fixed finger longer than the dactylus and with 4 teeth along the incisive margin, a maxilliped basis with 4 distal setae, and pereopod 1 propodus that is much longer than the combined length of unguis and dactylus. Leptochelia suhi n. sp. shares some features of L. myora with the first article of the uropod endopod longer than the second article and a maxilliped endite with 3 spiniform distal setae but can be differentiated by the cephalothorax being longer than the pleon, the relatively longer antennule article 3 compared to article 2, and the cheliped fixed finger with 3 robust teeth along the incisive margin. In this study, full descriptions of L. grandidentata and L. suhi are given, and a comparison with closely related species belonging to the ‘dubia/savignyi group’ is tabulated and discussed.

Evidence for Ontogenetic Feeding Strategies in Four Calanoid Copepods in the East Sea (Japan Sea) in Summer, Revealed by Stable Isotope Analysis

임동훈,위진희,서해립 한국해양과학기술원 2015 Ocean science journal Vol.50 No.3

Deciphering the ontogenetic feeding ecology of copepods is essential to understanding their role in the energy transfer of marine ecosystems. We used stable isotope analysis to examine the ontogenetic feeding strategies of the four coexisting calanoid copepods, Mesocalanus tenuicornis, Metridia pacifica, Calanus sinicus, and Neocalanus plumchrus, in the East Sea (Japan Sea) in summer. Moreover, we used the stable carbon and nitrogen isotope composition of small-sized plankton in three cell size fractions, pico- (< 2 μm), nano- (2–20 μm) and microplankton (20– 200 μm), to identify the dietary preference at each developmental stage. The relative carbon masses of pico-, nano- and microplankton were 18, 38, and 44%, respectively, and their δ13C and δ15N values gradually increased with increasing size classes. The ontogenetic trophic position of four copepods were relatively low and ranged from 2.1 to 2.6, indicating that herbivores feed on small-sized phytoplankton, pico- and nanoplankton. Among copepodid stages, the δ13C and δ15N values of M. tenuicornis and C. sinicus differed significantly, while those of M. pacifica and N. plumchrus were not significantly different. In M. tenuicornis, the smallest species among the four copepods examined, the diet preference of CIV for picoplankton changed to nanoplankton in the adult stage. When M. pacifica developed from CIV to adult, the diet preference changed from pico- to microplankton. The proportion of microplankton in the diet of C. sinicus and N. plumchrus increased from CIV to female adult and from CIII to CV, respectively. During the developmental progress in copepodid stages, the smaller copepods significantly changed their dietary preference from pico- to microplankton, while the larger copepods consistently fed on microplankton. We suggest that smaller copepods have an advantage in survival at early copepodid stages compared with larger copepods in summer when microplankton biomass is relatively low.