• Animal cells and systems
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• v.11 no.2
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• pp.215-225
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• 2007

The azooxanthellate soft coral Dendronephthya suensoni (Holem, 1895) is distributed mainly around Jejudo Island, Korea. This species was determined as gonochoric with a sex ratio of 2:1 (female:male). Both female and male colonies have one gametogenic cycle a year. The annual reproductive cycle of D. suensoni is dependent on the seawater temperature. In particular, reproduction of the male colony showed a higher positive correlation between seawater temperature and the mean diameter of the spermaries. Gametogenesis in females and males took 6 months and 12 months, respectively. The mean diameter of a mature oocyte was $249.29\;{\pm}\;36.24\;{\mu}m$, with a maximum size of $354.45\;{\mu}m$. Spawning could have occurred in the fall after the seawater temperature began to decrease.

• Animal cells and systems
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• v.4 no.4
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• pp.319-324
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• 2000

Species boundaries among the Alcyonacean soft coral, the genus Dendronephthya, are often obscured by inter- and intraspecific morphological variations. In the present study, we attempted to infer the genetic relationships of eight dendronephthians based on their molecular characters, the internal transcribed spacer (ITS) regions of ribosomal DNA, and then compared this result together with the random amplified polymorphic DNA (RAPD) data from our previous investigation. Dendronephthya. putteri and D. suensoni formed a divaricate form - VI grade specific clade, whereas D. castanea, D. gigantea, D. aurea and D. spinifera, formed a umbellate and glomerate form - IV and III grade specific clade. Therefore, we confirmed that the main characters the growth form and the anthocodial grade and formula, are important in identification of the species in dendronephthians despite some problems. Also, the relationships of the growth form are clarified as the glomerate form is much closer to the umbellate form than to the divaricate form based on two sets of independent molecular data. However, we cannot determine the molecular markers which limit the species boundaries among this genus with ITS sequences.

• Animal cells and systems
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• v.4 no.1
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• pp.1-7
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• 2000

The genus Dendronephthya, generally known as soft corals, is reported as an abundant and variable taxon. They mostly distribute in warmer waters of the Undo-Pacific Ocean region including Korea. In spite of their abundance and ecological importance as habitats of marine organisms, there are difficulties in the study of their identification and systematics because they have morphological variabilities and limited taxonomec characters. To resolve the problems, we attempted to elucidate the genetic relationships in the genus Dendronephthya by using random amplified polymorphic DNA (RAPD) analysis. This study was based on eight dendronephthian species and one Alcyoniidae species, Alcyonium gracillimum, as an outgroup. The results from all analysis suggest that they could be classified into four groups by the growth form and the anthocodial grades as follows: the first one,D. putteri and D. suensoni with the divaricate form and VI grade; the second one,D. sp.1 and D. sp.2 with the divaricate form and III or IV grade; the third one, D. gigantea and D. aurea being closer than D. spinifera with the glomerate form and III grade; the last one, D. castanea related to D. gigantea rather than D. putteri with the umbellate form and IV grade. Moreover, the divaricate form was separated from the group of the glomerate and umbellate form. At the intraspecies level, the types of the D. castanea, D. gigantea and D. spinifera were separated depending on the feature of spicules in the polyp head, and the coloration could not influence genetic variation. From this study, we can confirm that their morphological characters are compatible with the genetic variation, also RAPD analysis is a very useful method for resolving the systematic relationships of den-deonephthians.