How do whale barnacles live on their hosts? Functional morphology and mating-group sizes of Coronula diadema (Linnaeus, 1767) and Conchoderma auritum (Linnaeus, 1767) (Cirripedia: Thoracicalcarea)

Abstract

Whale-associated barnacles are intriguing in terms of their planktonic food sources, mating habits, and mechanisms of host attachment. We present observations of the whale-associated barnacles Coronula diadema (Linnaeus, 1767) and Conchoderma auritum (Linnaeus, 1767) obtained from dead humpback whales (Megaptera novaeangliae (Borowski, 1781)) collected in Korea. Shell bases of Coronula diadema are inflected and sharp-edged with hollow coring tubes at the periphery. The coring tubes are filled with whale skin, supporting the model that shell accretion into the whale skin is achieved by basal constriction to achieve strong attachment. Conchoderma auritum attaches to the shell surfaces of Coronula and has a pair of tubular ear-shaped structures on the capitulum. Both species have short and thick-segmented cirri that allow feeding in strong currents. The distal ends of the cirri in both species are often equipped with sharp, large claw-like setae, which are likely used to capture large zooplankton for food. Coronula diadema and Conchoderma auritum are simultaneous hermaphrodites. Coronula diadema can mate up to nine surrounding individuals. Conchoderma auritum lives in clumps and mating group size can up to 26 individuals.

Genomic insights into the sessile life and biofouling of barnacles (Crustacea: Cirripedia)

“…Barnacles (Thecostraca: Cirripedia) are sessile crustaceans ubiquitously present in marine environments from the intertidal to the deep-sea, and from the tropics to the polar regions; some of them even live on other marine organisms such as whales and turtles ( Chan et al., 2009 ; Buckeridge et al., 2018 , 2019 ; Kim et al., 2020 ). The subclass Cirripedia is divided into three infraclasses that differ in morphology and way of life: Thoracica includes acorn and stalked barnacles with phosphatic or calcified shells ( Chan and Høeg, 2015 ; Chan et al, 2021 ); Acrothoracica is characterized for not having shells but specifically burrowing into diverse calcareous substrates ( Chan et al., 2014 ; Nielsen et al., 2016 ); Rhizocephala includes endoparasitic barnacles of other crustaceans ( Anderson, 1994 ; Jung et al., 2019 ).…”

Abundance, placement and sexual identity of the epizoic barnacle Chelonibia testudinaria relative to the size and species of host turtles in Mabul Island, Malaysia

“…Barnacles (subclass Cirripedia) are sessile crustaceans that are commonly found attached to natural surfaces such as rocks, shells and corals (Chan & Høeg, 2015). However, those in the superfamily Coronuloidea specialize as obligate commensals of mobile marine animals including mammals, reptiles, chelicerates and large crustaceans (Badrudeen, 2000; Cheang et al ., 2013; Hayashi, 2013; Hayashi et al ., 2013; Zardus et al ., 2014; Carrillo et al ., 2015; Buckeridge et al ., 2018, 2019; Dreyer et al ., 2020; Kim et al ., 2020). They live as epibionts on the exterior body of their hosts of which sea turtles carry the widest variety (Frick & Pfaller, 2013; Hayashi, 2013); therefore, in analyses of associations between sea turtles and epibionts, much attention has been given to barnacles in particular (Zardus & Balazs, 2007; Pfaller et al ., 2008; Frick et al ., 2010; Fuller et al ., 2010).…”

The occurrence of the coronuloid barnacle Chelonibia Leach, 1817 as an encruster on mammalian bone in the central Mediterranean Sea

“…The above considerations about the unspecialised nature of the patula morph of C. testudinaria also suggest that the soft-and hard-part morphology of this form might represent a pivotal research target for reconstructing how and from where the unique host specialisations of the remainder of Coronuloidea (ROSS & NEWMAN, 1967;SEILACHER, 2005;KIM et al, 2020) evolved. Furthermore, they raise the question of whether the earliest members of this superfamily were preferential or obligate eipibionts on nektic and benthic-vagile hosts like their modern relatives, or they rather were encrusters or episkeletozoans on inanimate substrates (either biogenic or abiogenic).…”