Chaetoceros is a species-diverse genus of marine diatoms.The section Chaetoceros,recognized for the presence of numerous chloroplasts in both cell body and setae,is a common group of marine phytoplankton containing so...Chaetoceros is a species-diverse genus of marine diatoms.The section Chaetoceros,recognized for the presence of numerous chloroplasts in both cell body and setae,is a common group of marine phytoplankton containing some species,which may cause harm to marine organisms due to the robust setae.Modern taxonomic studies combining morphological and molecular data are still limited for the section Chaetoceros.To explore the diversity of the section Chaetoceros,monoclonal strains were established from the South China Sea and two novel species are described here,C.tetracarina sp.nov.and C.dicrinis sp.nov.Chaetoceros tetracarina is unique by the rimoportula on the anterior valve having four basal ridges supporting the external tube,whereas the other rimoportulae in the same chains or the one on the posterior valve for single cells each only possess a long external tube and lack basal ridges.Chaetoceros dicrinis is solitary and characterized by the symmetrical extending of the two setae on the same valve under light microscope(LM).The phylogenetic results show the presence of several groups within the section Chaetoceros.Chaetoceros tetracarina was sister to C.cf.pseudodichaeta,but differed by 33 and 46 bps in ribosomal large-subunit(LSU)and small-subunit(SSU)sequences respectively.The most closely-related species of C.dicrinis was C.denticulatus,but they were distinctly different morphologically,differing by 3 and 2 bps in LSU and SSU sequences respectively.This study provides new findings to understand the diversity of section Chaetoceros;however the inner relationships within this section remain largely unresolved.展开更多
基金Supported by the National Key Research and Development Program of China(No.2022 YFC 3105201)the National Natural Science Foundation of China(No.32170206)the Joint Fund of National Natural Science Foundation of China and NSFC-Shandong Joint Key Project(No.U 2106205)。
文摘Chaetoceros is a species-diverse genus of marine diatoms.The section Chaetoceros,recognized for the presence of numerous chloroplasts in both cell body and setae,is a common group of marine phytoplankton containing some species,which may cause harm to marine organisms due to the robust setae.Modern taxonomic studies combining morphological and molecular data are still limited for the section Chaetoceros.To explore the diversity of the section Chaetoceros,monoclonal strains were established from the South China Sea and two novel species are described here,C.tetracarina sp.nov.and C.dicrinis sp.nov.Chaetoceros tetracarina is unique by the rimoportula on the anterior valve having four basal ridges supporting the external tube,whereas the other rimoportulae in the same chains or the one on the posterior valve for single cells each only possess a long external tube and lack basal ridges.Chaetoceros dicrinis is solitary and characterized by the symmetrical extending of the two setae on the same valve under light microscope(LM).The phylogenetic results show the presence of several groups within the section Chaetoceros.Chaetoceros tetracarina was sister to C.cf.pseudodichaeta,but differed by 33 and 46 bps in ribosomal large-subunit(LSU)and small-subunit(SSU)sequences respectively.The most closely-related species of C.dicrinis was C.denticulatus,but they were distinctly different morphologically,differing by 3 and 2 bps in LSU and SSU sequences respectively.This study provides new findings to understand the diversity of section Chaetoceros;however the inner relationships within this section remain largely unresolved.
