Description of a new species of coral-inhabiting barnacle, Darwiniella angularis sp. n. (Cirripedia, Pyrgomatidae) from Taiwan

Benny K.K Chan,Yi-Yang Chen,Hsiu-Chin Lin

doi:10.3897/zookeys.214.3291

Abstract

The present study has identified a new species from the previously monotypic genus Darwiniella Anderson, 1992. Darwiniella angularis sp. n. is similar to Darwiniella conjugatum (Darwin, 1854) in external shell morphology and arthropodal characters. Darwiniella conjugatum, however, has a sharper tergal spur and a less obvious adductor plate angle when compared to Darwiniella angularis sp. n. Molecular analyses on mitochondrial DNA 12S rDNA and COI regions also support the morphological differences. Sequence divergences in 12S rDNA and COI between Darwiniella conjugatum and Darwiniella angularis sp. n. are 5% and 13% respectively, which are equivalent to the inter-specific sequence divergences in other barnacles. Both Darwiniella species are common on Cyphastrea Milne-Edwards and Haime, 1848 corals and Darwiniella angularis sp. n. is also collected from Astreopora de Blainville, 1830 corals in Taiwan.

Highlights

The coral-inhabiting barnacles of the genus Darwiniella Anderson, 1992 is a member of the family Pyrgomatidae, which has a symbiotic relationship with host corals
Small pieces of coral with barnacles embedded were collected with hammers and chisels at 5–20 m depth by SCUBA diving
A new species is identified from the previously monotypic genus Darwiniella that exhibit diagnostic morphological and molecular differences from D. conjugatum. These two species are difficult to distinguish from external shell morphology

Summary

Introduction

The coral-inhabiting barnacles of the genus Darwiniella Anderson, 1992 is a member of the family Pyrgomatidae, which has a symbiotic relationship with host corals. The species has a fused shell wall and a pair of fused opercular plates (scutum and tergum). Ross and Newman (1973) erected the genus Nobia to accommodate coral-inhabiting barnacles with fused shell plates and fused opercular valves, transferred P. conjugatum to Nobia conjugatum. Nobia conjugatum has a deep adductor plate and a distinct tergal spur, which is different from all Nobia species. Anderson (1992) erected the new genus Darwiniella to accommodate Nobia conjugatum and defined the genus as “ Wall flat, fused; sheath occupying about half inner wall; scutum and tergum calcified together, without visible line of juncture; deep adductor plate and conspicuous rostral tooth; elongate spur; basis oval, deep.”. Anderson (1992) erected the new genus Darwiniella to accommodate Nobia conjugatum and defined the genus as “ Wall flat, fused; sheath occupying about half inner wall; scutum and tergum calcified together, without visible line of juncture; deep adductor plate and conspicuous rostral tooth; elongate spur; basis oval, deep.” Anderson (1992) had not formally assigned the type species of Darwiniella and Ross (1999) designated the type species of Darwiniella as Darwiniella conjugatum (Darwin, 1854)

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Conclusion