Suggestion of new indentification keys devided into two groups in family Rhizosoleniaceae (Bacillariophyceae)

Abstract

To reveal the morphological differences of valve shape, structure of areolae and external process between genera in family Rhizosoleniaceae, rhizosolenid diatoms were collected at 32 sites during three years (2008 - 2010) in coastal waters of South Korea and western Arctic Ocean and were analyzed by using light and scanning electron microscopy. As a results, we identified 21 species (33% of total rhizosolenid diatoms) in 6 rhizosolenid genera, including Rhizosolenia, Proboscia, Pseudosolenia, Neocalyptrella, Guinardia, and Dactyliosolen. The six genera could be divided into two groups based on morphological diagnostic characters of valve shape and structure of areolae. The first group had distinguished keys, such as conoidal valve and loculate areolae: Rhizosolenia bergonii, R. formosa, R. hyalina, R. setigera f. pungens, R. setigera, R. borealis, R. hebetata f. hebetata, R. hebetata f. semispina, R. fallax, R. imbricata, Rhizooslenia sp.1, Rhizooslenia sp.2, Proboscia alara, P. indica, Pseudosolenia calcaravis, and Neocalyptrella robusta. The second group, involving Guinardia delicatula, G. flaccida, G. striata, Dactyliosolen fragilissimus, and D. phuketensis showed a flat or rounded valve and poroid areolae. Therefore, we suggest that classification keys devided into two groups could easily be further classified in family Rhizosoleniaceae.ers of South Korea and western Arctic Ocean and were analyzed by using light and scanning electron microscopy. As a results, we identified 21 species (33% of total rhizosolenid diatoms) in 6 rhizosolenid genera, including Rhizosolenia, Proboscia, Pseudosolenia, Neocalyptrella, Guinardia, and Dactyliosolen. The six genera could be divided into two groups based on morphological diagnostic characters of valve shape and structure of areolae. The first group had distinguished keys, such as conoidal valve and loculate areolae: Rhizosolenia bergonii, R. formosa, R. hyalina, R. setigera f. pungens, R. setigera, R. borealis, R. hebet