Review of the genus monotheca (Hydrozoa: Leptolida) from Australia with description of a new species and a note on monothecella stechow, 1923

Abstract

Monotheca Nutting, 1900 is a genus with few known species worldwide. It is an artificial genus, as some species of the Plumulariidae sometimes have one or two hydrocladial hydrothecae and are thus borderline between Monotheca and Plumularia. This review considers only Australian species with consistently monothecate hydrocladia; species with more than one hydrotheca on the hydrocladium are considered to belong to Plumularia. Ten species referrable to Monotheca are reported from southeast Australia; three are synonymised here in other species, four are presently known to be endemic to Australia and one species, Monotheca amphibola, is described as new. The gonosome of Monotheca togata is described for the first time. Monothecella is synonymised in Monotheca. A key to the Australian species of Monotheca is given.