The rise and fall of pyrgopsella youngi - rediscovery of a lost species

The coral-inhabiting barnacle Pyrgopsella annandalei was collected in 1888 off the reefs of the Andaman Islands in the Indian Ocean, diagnosed in 1906, and described in full in 1907. Since then, this barnacle has not been recorded. In 2006, several specimens of Pyrgopsella were found embedded in the hermatypic coral Symphyllia radians. Based on morphological differences between this material and the drawings and written description of P. annandalei, the specimens from Symphyllia were assigned to a new species, P. youngi. The discovery of a single individual of Pyrgopsella in the collection of the Natural History Museum, London, labeled "cotype," and its comparison to the recent material from Symphyllia, revealed that the differences between P. annandalei and P. youngi represent no more than intraspecific morphological variation. This conclusion is supported by a comparison of the DNA sequences of the CO1 and 12S rRNA genes from specimens representing both morphological varieties. It is concluded that P. youngi is a junior synonym of P. annandalei, and the latter name should be used in its place.