A report of three unrecorded Ellobiid species (Gastropoda, Eupulmonata) from Korea

Lee, Jun-Sang,Lee, Yong-Seok The Malacological Society of Korea 2015 The Korean Journal of Malacology Vol.31 No.4

Three species of Ellobiid molluscs collected from Korea were identified as Auriculastra duplicata (Pfeffer, 1854), Laemodonta siamensis (Morelete, 1875) and Melampus (Pira) flavus (Gmelin, 1791). This is the first record from the Korea, providing a description of the species with illustration for the shell morphology. Including the new recorded in this study, the family Ellobiidae contained six genera and 13 species in the Korea.

Bivalve mollusks in Ulsan Bay (Korea)

Lutaenko, Konstantin A. The Malacological Society of Korea 2014 The Korean Journal of Malacology Vol.30 No.1

The bivalve molluscan fauna of Ulsan Bay, East Sea coast of Korea, is summarized, based on original and literature data. The fauna consists of 61 species belonging to 20 families. Seven species are identified only to genus level. Two species (Carditellopsis toneana (Yokoyama, 1922), Carditidae and Fulvia hungerfordi (G.B. Sowerby III, 1901), Cardiidae) are new records for the East Sea coast of Korea, and one species (Crenella decussata (Montagu, 1808), Mytilidae) is a new record for Korea. Biogeographically, Ulsan Bay's bivalve fauna is subtropical with a predominance of tropical-subtropical species, 21 species, or 39% of the total species number, subtropical, 14 species, or 26%, and subtropical-boreal (mostly subtropical-lowboreal), 11 species, 21%, totalling 86%. A remarkable feature of the Ulsan Bay fauna is the presence of tropical-subtropical species not found in Yeongil Bay but common in tidal flats and shallow waters of the Yellow Sea and the southern part of Korea. A cold water mass appearing off the southeast coast of Korea near Ulsan in summer seems responsible for the presence of boreal-arctic species in this area.

A New Record of Myurella nebulosa (Terebridae: Gastropoda) from Korea

Jung, Daewui,Lee, Sang-Hwa,Choe, Yeongjae,Park, Joong-Ki The Malacological Society of Korea 2015 The Korean Journal of Malacology Vol.31 No.2

We report a new record of Myurella nebulosa (Sowerby, 1825) collected by SCUBA diving from sandy bottom of subtidal zone in Jeju Island in Korea. The specimen of M. nebulosa is distinguished from its congeners by having slightly plump shell, high spire, distinctive subsutural band, deep axial ribs, numerous and shallow spiral ribs, ivory in color. In this report, we provided a brief morphological description and photographs of M. nebulosa. An unrooted phylogenetic tree for mitochondrial cox1 sequences using NJ analysis found Korean M. nebulosa sample was clustered with its conspecific sequences, but clearly separated from M. columellaris that is not easy to distinguishable based on external shell morphology alone.

Bivalve Mollusks in Yeongil Bay, Korea. 2. Faunal Analysis

Lutaenko Konstantin A.,Je, Jong-Geel,Shin, Sang-Ho The Malacological Society of Korea 2006 The Korean Journal of Malacology Vol.22 No.1

A list of species of bivalve mollusks, their local distributions and relative abundance in Yeongil Bay were analysed. Species richness ranging from 1 to 37 species was low (less than 10) in some stations at the entrance and in the central part of the bay. Fifteen species (Acila insignis, Nucula tenuis, Yoldia notabilis, Mytilus galloprovincialis, Arca boucardi, Axinopsida subquadrata, Felaniella usta, Mactra chinensis, Raeta pulchella, Nitidotellina hokkaidoensis, Theora fragilis, Alvenius ojianus, Callithaca adamsi, Ruditapes philippinarum and Laternula anatina) were most frequently encountered, and seven of them were most abundant numerically (per sample): Th. fragilis in the inner bay, A. insignis, N. tenuis, and A. ojianus in the outer bay, and C. adamsi, A. subquadrata, R. puichella in both parts. Local distributions of common species were described and presented in plotted data, and three distribution patterns were recognized. Biogeographical analysis shows that a majority of species (55%) belongs to the subtropical group, tropical-subtropical species (16%) play a relatively significant role, and the percentage of boreal (temperate) and boreal-arctic species is 18% which characterizes the whole fauna as subtropical. Zonal-biogeographical composition and number of species in families in Yeongil Bay are compared with those of some Japanese (Wakasa and Mutsu) and Russian (Peter the Great, Possjet and Amursky) bays of the East Sea. The absence of a number of typical warm-water embaymental mollusks in Yeongil Bay found in the north further East Sea and Japan, and the similar zonal-biogeographical structure of the inner and outer bay faunas are explained by active water exchange due to the openness of the bay, relatively low summer temperatures, and presence of upwelled cold waters.

Biological environmental characteristics in Habitats of an abalone Haliotis diversicolor in the eastern coast of jeju-do, Korea

Yoo, Joon-Taek,Choi, Young-Min,Yang, Moon-Ho,Im, Yang-Jae,Ko, Joon-Chul,Chang, Dae-Soo The Malacological Society of Korea 2009 The Korean Journal of Malacology Vol.25 No.3

This study describes biological environmental characteristics in natural habitats of Haliotis diversicolor in the coastal area of Sungsanpo located in the eastern coast of Jeju-do, Korea. The field survey was monthly conducted from May 2006 to February 2007. H. diversicolor, sea urchin, turban shell and marine algae were collected by two divers using SCUBA. The species composition of demersal fishes were seasonally investigated by fish traps in 2007. During the study period, more than 67% of H. diversicolor and sea urchin were found in the depth shallower than 5 m, and more than 64% of turban shell were found in the depth deeper than 3 m. The dominant algal species in May were generally Undaria pinnatifida, Ecklonia cava, Sargassum. spp. and coralline algae. Most of demersal fishes collected by the fish traps were wrasses which have been reported as a major predator of young abalone.

Utilizing the grazing effect of fresh water clams (Unio douglasiae) for the remediation of algal bloom during summer

Nam, Ki-Woong,Lee, Jeong-Ryul,Park, Kyung-Il The Malacological Society of Korea 2015 The Korean Journal of Malacology Vol.31 No.1

The occurrence of 'algal bloom', caused by the mass proliferation of phytoplankton, causes serious problems in streams and lakes in Korea. Therefore, in this study, the phytoplankton filter-feeding trait of Unio douglasiae, a type of freshwater clam, was used to reduce the algal bloom in outdoor water tanks during the summer. This involved the construction of a U. douglasiae cultivation apparatus, wherein 1,000 clams were divided into 8 rectangular baskets arranged in the shape of an empty square. The control tank was manufactured in exactly the same shape within the water tank, but without the addition of clams. The algal bloom-reducing effect of U. douglasiae was confirmed by the measurement of (and comparing between) the water quality at the center and periphery of the test and control cultivation apparatus. Water quality measurements included the measurement of water temperature, pH, turbidity, dissolved oxygen (DO) content, and chlorophyll-${\alpha}$ concentrations; the water quality was measured twice a month between June and November 2014.The results of these analyses did not show a significant difference in water quality (temperature, pH, turbidity, DO) between the center and periphery of the test and control tanks. However, the chlorophyll-${\alpha}$ concentration was observed to be much lower at the center of the test tank compared to that at the center and periphery of the control tank, as well as at the periphery of the test tank. This was believed to be a result of the U. douglasiae surrounding the center of the test tank, which prevented the influx of plankton from the periphery. Accordingly, the results of these analyses suggest the possibility that U. douglasiae cultivation could reduce the proliferation of algal blooms in lakes and streams during the summer. In particular, these results indicate possible improvements in U. douglasiae activity (reduction in algal blooms) by their effective arrangement in the water bodies.

Gonadal Development and Reproduction in the Trumpet Shell, Charonia sauliae

강경호,김재민,선승찬,김현정,Kang, Kyoung-Ho,Kim, Jae-Min,Seon, Seung-Cheon,Zhuo, Liang Liang,Lim, Sang-Min,Kim, Hyeon-Jeong The Malacological Society of Korea 2009 The Korean Journal of Malacology Vol.25 No.1

This study devised and tested a histological staging system for gonadal development in the trumpet shell, Charonia sauliae, which was collected along the south coast of Jeju Island, South Korea. This paper details for the first time the gonadal development characteristics of C. sauliae. Ovary and testis development in C. sauliae can be roughly divided into five stages: growing, mature, spent, degenerative, and resting. The trumpet shelll has multiple fecundation and fertilization during the spawning season for out-of-step gonadal development in high-temperature and low-salinity environments. Female trumpet shell tended to have larger shells and were more abundant than males (64.26% of all animals collected were female).

Ultrastructural Study of the Process of Oocyte Degeneration and Function of the Follicle Cells in Female Spisula sachalinensis on the East Sea of Korea

Chung, Ee-Yung,Lee, Ki-Young,Lee, Jeong-Yong The Malacological Society of Korea 2008 The Korean Journal of Malacology Vol.24 No.1

Ultastructural studies of oocyte degeneration and follicle cells in female Spisula sachalinensis are described for clams collected from Jumunjin, Gangwondo, Korea. The follicle cells playan integral role in vitellogenesis and oocyte degeneration by assimilating products originating from the degenerated oocytes (thus allowed the transfer of yolk precursors needed for vitellogenesis). The functions of the follicle cells include phagocytosis and intracellular digestion of products originating from oocyte degeneration. During the period of oocyte degeneration, follicle cells of this species probably have lysosomal systems for the breakdown and reabsorption of various phagosomes(phagolysosomes) in the cytoplasm for nutrient storage; this process has been observed in other bivalves.

Systematic Relationships of Korean Freshwater Snails of Semisulcospira, Koreanomelania, and Koreoleptoxis (Cerithiodiea; Pleuroceridae) revealed byMitochondrial Cytochrome Oxidase I Sequences

Kim, Woo-Jin,Kim, Dae-Hee,Lee, Jun-Sang,Bang, In-Chul,Lee, Wan-Ok,Jung, Hyung-Taek The Malacological Society of Korea 2010 The Korean Journal of Malacology Vol.26 No.4

Many freshwater snail taxa are difficult to identify using morphological traits due to phenotypic plasticity. However, using of molecular DNA marker in combination with morphological traits can provide a reliable means for discriminating among freshwater snail taxa including cryptic species. To discriminate among Korean freshwater snail taxa and resolve their systematic relationships, wesequenced a fragment of mtDNA cytochrome oxidase I (COI) gene from 82 specimens collected from ten different sites distributed along the Korean peninsula. We identified more than seven freshwater snail taxa including cryptic species in Korea. Whereas traditional shell morphology of freshwater snails offers only weak discriminatory power for recognizing 'good' taxa, DNA sequence data provided positive and reliable identification. In addition, a major Semisulcospira clade was clearly separated from the remaining lineages observed including cryptic species. However, a phylogenetic tree inferred from the COI gene data did not fully resolve systematic relationships among pleurocerid taxa in Korea. Establishing more robust shell characteristics for identifying taxa unambiguously and hence improving traditional key shell morphology characters for freshwater snail species is an urgent requirement and will require more rigorous examination of all nominal taxa. While molecular data generated here will be useful for species identification and for describing the systematic relationships among Korean freshwater snails, further analysis will be required.

Oogenesis and Oocyte Degeneration in Coecella chinensis (Bivalvia: Mesodesmatidae)

Kim, Sung Han,Chung, Ee-Yung The Malacological Society of Korea 2014 The Korean Journal of Malacology Vol.30 No.4

Ultrastructural studies of oogenesis in oocytes, oocyte degeneration associated with the follicle cells in female Coecella chinensis were investigated for clams collected from Namhae, Geongsangnam-do, Korea. In this study, vitellogenesis during oogenesis in the oocytes occured by way of endogenous autosynthesis and exogenous heterosynthesis. Of two processes of vitellogenesis during oogenesis, the process of endogenous autosynthesis involved the combined activity of the Golgi complex, mitochondria and rough endoplasmic reticulum. whereas the process of exogenous heterosynthesis involved endocytotic incorporation of extraovarian precursors at the basal region of the oolema of the early vitellogenic oocytes prior to the formation of the vitelline coat. It is assumed that the follicle cells were involved in the development of previtellogenic and early vitellogenic oocytes and appear to play an integral role in vitellogenesis in the early and late vitellogenic oocytes by endocytosis of yolk precursors, and also they were involved in oocyte degeneration by assimilating products originating from the degenerated oocytes, thus allowed the transfer of york precursors needed for vitellogenesis (through phagocytosis by phagolysosomes after spawning). Follicle cells presumably have a lysosomal system for breakdown products of oocyte degeneration. and for reabsorption of various phagosomes (phagolysosomes) in the cytoplasm for nutrient storage during the period of oocyte degeneration.