Remarkable convergent evolution in specialized parasitic Thecostraca (Crustacea)

Abstract

Background: The Thecostraca are arguably the most morphologically and biologically variable group within the Crustacea, including both suspension feeders (Cirripedia: Thoracica and Acrothoracica) and parasitic forms (Cirripedia: Rhizocephala, Ascothoracida and Facetotecta). Similarities between the metamorphosis found in the Facetotecta and Rhizocephala suggests a common evolutionary origin, but until now no comprehensive study has looked at the basic evolution of these thecostracan groups.

Merging evolutionary history into species interaction networks

“…However, other factors such as host switching behaviour between unrelated host lineages (Johnson et al . ) and trait convergence in unrelated predator species (Perez‐Lozada, Hoeg & Crandall ) may also contribute to shape modularity in antagonistic networks (Krasnov et al . ).…”

“Crustacea”: Cirripedia

“…The Ascothoracida is a small group of parasites infesting either gorgonian anthozoans or echinoderms (Høeg et al 2005 ). The Facetotecta are known only as larvae, but their metamorphosis, now observed in vitro in the laboratory, provides strong evidence that the adults are endoparasitic in yet to be identifi ed hosts (Glenner et al 2008 ;Pérez-Losada et al 2009 ). Molecular data unequivocally puts Facetotecta as sister group to an Ascothoracida + Cirripedia clade.…”

Evolutionary Developmental Biology of Invertebrates 4

“…Thecostracan monophyly is assured both by molecular evidence (Pérez-Losada et al 2004 ) and by larval apomorphies, notably the presence of a terminal stage adapted for attachment and called y-cypris (Facetotecta), a-cypris (Ascothoracida), and cypris (Cirripedia). The Facetotecta are known only as larvae, but their metamorphosis, now observed in vitro in the laboratory, provides strong evidence that the adults are endoparasitic in yet to be identifi ed hosts (Glenner et al 2008 ;Pérez-Losada et al 2009 ). The Facetotecta are known only as larvae, but their metamorphosis, now observed in vitro in the laboratory, provides strong evidence that the adults are endoparasitic in yet to be identifi ed hosts (Glenner et al 2008 ;Pérez-Losada et al 2009 ).…”