Saturday 18 August 2012

A new species of Barnacle from Taiwan.

Barnacles are Crustaceans, related to Shrimps, Crabs and Lobsters, but having a remarkably different lifestyle, with a free-swimming larval stage that then settles on rocks, or other substrates, and becomes an immobile filter-feeder, protected by a mineralized shell. Some species have become parasites on other Crustaceans, and have even more modified body-plans, growing through the host's tissues like a fungus.

In a paper published in the journal Zookeys on 7 August 2012, Yi-Yang Chen of the Institute of Ecology and Evolutionary Biology at the National Taiwan University, Hsiu-Chin Lin of the Biodiversity Research Center at Academia Sinica and Benny K.K. Chan of both, describe a new species of Barnacle discovered during a study of Darwiniella conjugatum, a widespread tropical species found living on Coral Reefs from the Pacific to the Red Sea.

Chen et al. took samples of 'Darwiniella conjugatum' from five sites on Taiwan and nearby islands. They found that many of the specimens examined differed from typical Darwiniella conjugatum, when their internal structure was examined; a DNA analysis confirmed these specimens were in fact a new species.

Map showing the areas where Barnacles were sampled. Chen et al. (2012).

The new species in named Darwiniella angularis, where angularis refers to the presences of the obvious adductor plate angle, an internal feature considered diagnostic of the species. It was found growing on the coral Astreopora sp. at Lobster Cave on Siaoliouciou Island and on Cyphastrea chalcidicum on the Turtle Tail on Turtle Island. Its external structure is identical to that of Darwiniella conjugatum, making it a cryptic species. Since this study only included specimens from Taiwanese waters, it is quite likely that the species is more widespread, and that the wide geographical range of Darwiniella conjugatum, includes other cryptic species.

Darwiniella angularis. (A) Dorsal view of shell. (B) Ventral view
of shell. Scale bars are in μm.  Chen et al. (2012).

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