Antennular specialization in cyprids of coral associated barnacles

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We used video, light and scanning electron microscopy to study the cypris larvae in species of coral inhabiting barnacles (Pyrgomatidae) in search of adaptations to settlement on their highly unusual substratum. Species studied were Savignium crenatum, Trevathana jensi, Trevathana margaretae, Trevathana mizrachae and Trevathana sarae. In all ¿ve species the third antennular segment was shaped like a spearhead with only an extremely narrow attachment disc. This morphology represents the most extreme antennular
specialization known from cirripedes, and it is not even matched by those parasitic barnacles that use the antennule for active penetration of cuticles. Compared to the third segment, the ¿rst, second and fourth segments exhibit no obvious specializations, and the armament of sensory setae is also as very comparable to that seen in balanomorphan cirripedes. The coral barnacles also have the nauplius eye, compound eyes, frontal ¿laments, lattice organs and cement glands known from other barnacles. Only T. sarae differed by
having two unusually shaped setae terminally on the fourth segment. Video observations showed that the coral barnacle cyprids display the exploratory walking behaviour known from cyprids settling on hard bottom substrata. We interpret the pointed structure of the third antennular segment as an adaptation to penetrate through live coral tissue. Projecting this character ono a recent phylogenetic tree of balanomorphan species indicates that it is an apomorphy for a large clade of coral inhabiting barnacles.
TidsskriftJournal of Experimental Marine Biology and Ecology
Udgave nummer1-2
Sider (fra-til)115-124
Antal sider10
StatusUdgivet - 2010

ID: 33764156