title: Trichocytes in Lithophyllum kotschyanum and Lithophyllum spp. (Corallinales, Rhodophyta) from the NW Indian Ocean.
abstract: The current diagnosis of the genus Lithophyllum includes absent or rare trichocyte occurrence. After examining holotype material, single trichocytes have been revealed to occur abundantly in Lithophyllum kotschyanum Unger, and in freshly collected specimens of Lithophyllum spp. from the Red Sea, Gulf of Aden and Socotra Island (Yemen). Trichocyte occurrence is not considered a diagnostic character at specific or supraspecific levels in the Lithophylloideae, and the ecological significance of trichocyte formation is discussed. The generitype species, L. incrustans Philippi, does not show trichocytes nor do many other Lithophyllum species from diverse geographic localities, but the presence of abundant trichocytes in other congeneric taxa requires emendation of the genus diagnosis. Therefore, the diagnosis of Lithophyllum is here emended by eliminating the adjective "rare" in the sentence concerning trichocyte occurrence, as follows: "Trichocytes present or absent, if present occurring singly."
authors.affiliation: Dip.to di Sc. dell'Ambiente e del Territorio e di Scienze della Terra, Sez. di Sc. Geologiche e Geotecnologie, Università degli Studi di Milano-Bicocca, Piazza della Scienza 4, Milano, 20126, Italy.
authors.forename: Daniela
authors.initials: D
authors.lastname: Basso
authors.affiliation: Dip.to di Sc. dell'Ambiente e del Territorio e di Scienze della Terra, Sez. di Sc. Geologiche e Geotecnologie, Università degli Studi di Milano-Bicocca, Piazza della Scienza 4, Milano, 20126, Italy.
authors.forename: Annalisa
authors.initials: A
authors.lastname: Caragnano
authors.affiliation: Dip.to di Bioscienze, Università degli Studi di Milano, Via Celoria 26, Milano, 20133, Italy.
authors.forename: Graziella
authors.initials: G
authors.lastname: Rodondi
keywords: Indian Ocean; Lithophyllum kotschyanum; Red Sea; TRH; Unger; coralline algae; holotype; trichocyte