Chthamalus Ranzani, 1817

Carriol, René-Pierre, 2008, New genus and new species of Cirripedia (Chthamalidae, Tetraclitidae, Archaeobalanidae and Balanidae) from the Middle Miocene of the faluns of Touraine (France), Zootaxa 1675, pp. 31-48 : 33

Genus Chthamalus Ranzani, 1817

Type species: Chthamalus stellatus ( Poli, 1791) by original designation.

Diagnosis: Wall of six plates, rostrum and carina provided with alae, rostrolaterals without alae, parietes and radii not permeated by pores, basis membranous.

Fossil species: In addition to the three species of Chthamalus from the Middle Miocene of the faluns of Touraine, the extinct Chthamalus are: C. stellatus from the Pleistocene of Italy and Chthamalus ligusticus De Alessandri, 1894 from the Pliocene of Italy, both described by De Alessandri (1894).

The taxonomic attribution of the other extinct Chthamalus has been revised. Bosquet (to Schlüter, 1887) has declared that Chthamalus darwini Bosquet, 1857 (Maastrichtian, Limburg, Germany) is conspecific with a Recent species (see Jagt & Carriol submitted). De Alessandri (1894) has concluded that the two species described by Locard (1878), C. stellatus (Miocene, Drôme, France) and Chthamalus revilei Locard, 1878 (Middle Miocene, Rhône, France), are not Chthamalus : the former is Balanus stellaris ( Brocchi, 1814) and the latter cannot be attributed to the genus Chthamalus . I agree with him, I have examined the specimen of C. revilei (held in the collections of the Muséum d’Histoire naturelle de Lyon, Rhône, France) and it shows tubiferous parietes and radii. Furthermore, after Ortmann (1902), the species Chthamalus antiquus Philippi, 1887 , recorded from Miocene of Chile, is in fact Solidobalanus varians ( Sowerby, 1846) .

Therefore, Chthamalus species from the faluns of Touraine represent the earliest known representatives of the genus.

The extinct species of Chthamalus cannot be included in the classification of the extant ones, as this classification is based on characters of the cirri and trophy, which do not fossilize.