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Vol. 52, 2013
Molecular analyses of shallow-water zooxanthellate zoanthids
(Cnidaria: Hexacorallia) from Taiwan and their Symbiodinium spp
James
Davis Reimer*, Yuka Irei, Takuma Fujii and Sung-Yin Yang
1Molecular
Invertebrate Systematics and Ecology Laboratory, Graduate School of
Engineering and Science, Univesity of the Ryukyus, Senbaru 1,
Nishihara, Okinawa 903-0213, Japan
Abstract
Background: Although we previously
reported on surveys of shallow-water zoanthid (Anthozoa: Hexacorallia:
Zoantharia) species diversity from localities in Taiwan, no study has
yet examined the molecular phylogeny of the majority of specimens, nor
has any study examined zoanthid zooxanthellae (Symbiodinium spp.) diversity in
Taiwan. As many phylogenetic results have been reported from Japan, a
critical step in testing DNA identification of zoanthids and their
symbionts is the application of these techniques to specimens from
neighboring regions such as Taiwan. We utilized three DNA markers
(mitochondrial cytochrome oxidase subunit I (COI), mitochondrial 16S
ribosomal DNA (mt 16S rDNA), and the nuclear internal transcribed
spacer region of ribosomal DNA (ITS-rDNA)) to examine the molecular
phylogeny of 110 zooxanthellate specimens collected from 10 localities
in Keelung, Kenting, and Green Island. Additionally, we report on the
types of Symbiodinium spp.
(zooxanthellae) from the three regions above plus the Penghu Islands,
utilizing sequences of ITS2-rDNA.
Results: Most specimens in the suborder
Brachycnemina belonged to previously reported species. However, it
appears that there are still some undescribed Palythoa species groups
in the northwestern Pacific that are cryptic in having small colony
sizes (<5 polyps) and occurring in low numbers. With regards to Symbiodinium spp. diversity, Palythoa tuberculosa and Palythoa mutuki associated with
subclade C1 and related types, Zoanthus
sansibaricus associated
with subclade C3-derived types, and Zoanthus
kuroshio that harbored
C15/C91-related Symbiodinium.
Notably, 1/2 of the P. tuberculosa
specimens from the Penghu Islands
harbored a previously unreported clade C symbiont, and two Zoanthus. vietnamensis specimens from Keelung
also had a unique symbiont type within clade C.
Conclusions: It appears that
undescribed Palythoa species
in the northwestern Pacific may be widely distributed yet low in
numbers, often cryptic in their habitat, and with a small colony size.
As well, it is clear that much work remains to understand
zoanthid-symbiont associations in Taiwan.
Key words: Marine biodiversity; COI; mt 16S
rDNA; ITS-rDNA; Taiwan; Zoanthid; Zooxanthellae.
*Correspondence: E-mail: jreimer@sci.u-ryukyu.ac.jp
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