Abstract
The present study investigated the phylogeography of the intertidal barnacle Tetraclita in the Gulf of Thailand ecoregion (Sunda Shelf Province in the Pacific) and the Andaman Sea Coral Coast ecoregion (Andaman Province in the Indian Ocean) in Thailand’s waters. Tetraclita species were identified by a combined morphological and molecular approach using mitochondrial gene fragments (CO1 and 12S rRNA). Tetraclita singaporensis is a major occupiers on the Andaman coast but is sparse in the western Gulf of Thailand. Tetraclita squamosa inhabits almost all of our collection sites in the Gulf of Thailand but has a very low abundance in the Andaman Sea. Tetraclita kuroshioensis has two genetically distinct populations, one in the Andaman Sea and the other in the West Pacific region. S-DIVA analysis showed that the most recent common ancestor (MRCA) of T. kuroshioensis was distributed in both the Andaman Sea and West Pacific region, with a relative probability of 63%; the analysis further identified two molecular subclades, one on each side of the Sunda Shelf by vicariance about 0.53 million years ago, far before the Last Glacial Maximum (LGM). The MRCA of T. squamosa was based in the West Pacific region (relative probability: 90%), and dispersed into the Andaman Sea after the LGM. The MRCA of T. singaporensis was in the Andaman Sea (relative probability: 89.5%) and dispersed into the Gulf of Thailand via monsoonal currents through the Malacca Strait after the LGM. Presently, T. singaporensis is absent from the West Pacific region, further supporting its origin in the Andaman Sea. The distribution of intertidal barnacles in the Sunda Shelf and Andaman provinces is a result of the interplay between geological events and present day oceanographic currents.
Highlights
The Indo-Pacific region contains the world’s highest marine biodiversity (Roberts et al, 2002), a result of interactions among ocean topography, complicated oceanographic current patterns, and geological events such as sea level fluctuations (Ni et al, 2014)
According to the results of the ABGD analysis (Supplementary Table 1), all the specimens collected from Thailand were designated into three species, T. kuroshioensis, T. singaporensis, and T. squamosa
Tetraclita is an intertidal barnacle widely distributing in the Indo-West Pacific that comprises several morphologically similar cryptic species
Summary
The Indo-Pacific region contains the world’s highest marine biodiversity (Roberts et al, 2002), a result of interactions among ocean topography, complicated oceanographic current patterns, and geological events such as sea level fluctuations (Ni et al, 2014). Intertidal species are mainly dispersed by the planktonic phases which can be affected by the length of the planktonic larval development period, present day oceanographic current patterns, and geological historical events, such as Pleistocene glaciations and sea level fluctuations (Tsang et al, 2012). Before the use of DNA barcodes in species diversity studies, Tetraclita squamosa was believed to be distributed throughout the Indo-Pacific waters (Pilsbry, 1916; Newman and Ross, 1976). Tetraclita serrata, distributed in the West Indian Ocean, is sister to T. kuroshioensis (Tsang et al, 2012, 2015)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
