Pyrgospongia, Achituv, Yair & Simon-Blecher, Noa, 2006

Achituv, Yair & Simon-Blecher, Noa, 2006, Pyrgopsella (Cirripedia: Balanomorpha: Pyrgomatidae) is not a sponge­inhabiting barnacle, Zootaxa 1319, pp. 29-42 : 39

Pyrgospongia gen. nov.

Diagnosis: Wall concrescent, thin, made of radiating rods connected by chitinous material, elliptical in outline; ribs on shell absent; heath absent. Basis membranous. Scutum and tergum not fused, scutum transversally elongated, tergum triangular.

Type species: Pyrgopsella stellula Rosell, 1973 .

Etymology: From the Greek pyrgos (tower), found in the family name Pyrgomatidae of the coral­inhabiting barnacles, and the Latin (from Greek) spongia (sponge), referring to the host group.

Remarks: Based on the morphology of the shell and the opercular valves, Ross & Newman (1973) suggested that Pyrgopsella annandalei is an offshot of the “ Savignium line” of pyrgomatids. Anderson (1992) suggested that P. annandalei is a specialized member of the line of Savignium crenatum (Sowerby) . However, the opercular valves of our material, as well of the material depicted by Gruvel (1907), are closer in form to those of Trevathana dentata (Darwin) ; a tergal tooth and a thin, pointed, inward­projecting tooth located on the spur are characteristic of T. dentata but missing in Savignium crenatum . The position of Pyrgospongia is more ambiguous. The opercular valves, elongated scutum, and especially the tergum of Pyrgospongia stellula , without any sign of an internal tooth, appear to be more similar to those of a different pyrgomatid line comprising those species of Cantellius with transversally elongated scuta, such as C. brevitergum (Hiro) or C. transversalis (Nilsson­Cantell) . It might be supposed that Pyrgospongia was derived from within Cantellius . On the other hand, being a sponge­inhabiting rather than coralinhabiting barnacle and having rather pleisomorphic opercular valves, the Philippine and Japanese P. stellula may not be a pyrgomatid at all. Molecular analysis using DNA sequences may shed light on this enigma.