Do giant barnacles contribute to deep-water biogenic reef formation in Maltese waters?

Deep-sea ROV surveys in the west Malta Graben allowed re-evaluation of previous work on the association of the giant barnacle, Pachylasma giganteum, with cold-water corals and other habitat-forming species, and this species’ contribution to formation of biogenic structures. While only a minor contributor to habitat architecture when anthozoans and other large sessile species are dominant, P. giganteum may become a habitat-former in the absence of competing species.peer-reviewe

The Cretaceous acorn barnacle <i>Archaeochionelasmus nekvasilovae</i> Kočí, Newman and Buckeridge, 2017 (Cirripedia, Neobalanomorpha) is a fragmentary rudist (Bivalvia, Mollusca)

The unique holotype of Archaeochionelasmus nekvasilovae Kočí, Newman and Buckeridge, 2017, from the upper Cenomanian of the Czech Republic, supposedly an early neobalanomorph belonging to the extant family Chionelasmatidae, is compared in detail with chionelasmatids and rudist bivalves. The morphology and shell structure demonstrate that, rather than being a barnacle, it is a poorly preserved fragment of a rudist, which roughly mimics the form of an incomplete balanomorph wall

A New and Primitive Barnacle (Cirripedia: Balanomorpha) from the North Fiji Basin Abyssal Hydrothermal Field, and Its Evolutionary Implications

A new sessile barnacle, Eochionelasmus ohtai, n. gen., n. sp., has been discovered associated with an abyssal hydrothermal vent at 1990m depth in the North Fiji Basin, Southwest Pacific. The genus is distinguished from its closest and bathyal relative, Chionelasmus, in having distinct, multiple whorls of basal imbricating plates. These and other characters render it the most primitive living member of the suborder Balanomorpha. Knowledge of the organization of its shell, and of the ontogeny of the shell wall in Chionelasmus, profoundly alters our understanding of the evolution of balanomorph barnacles, and a new hypothesis is proposed. Two previously described abyssal hydrothermal barnacles also proved to represent the most primitive living members of their suborder s: Scalpellomorpha and Verrucomorpha. It may be puzzling why three such antiquated morphologies should have persisted in association with abyssal hydrothermal springs while their antecedents became extinct elsewhere. However, barnacles are noted f(or their adaptability to a wide range of habitats including rigorous environments such as estuaries, the highest intertidal, and the effluent from power plants. The notable feature here, in contrast to their conservative but distinctly different shell morphologies, is the uniquely convergent adaptation of their setose feeding mechanism to vent-related food sources

Biological features on epibiosis of Amphibalanus improvisus (Cirripedia) on Macrobrachium acanthurus (Decapoda)

This study aimed to describe the epibiosis of barnacles Amphibalanus improvisus on eight adult Macrobrachium acanthurus males from the Mundaú Lagoon, state of Alagoas, Brazil. The number of epibiont barnacles varied from 247 to 1,544 specimens per prawn; these were distributed predominantly on the cephalothorax and pereiopods, but also on the abdomen and other appendices. Although some were already reproducing, most barnacles had been recruited recently or were still sexually immature; this suggests recent host arrival in that estuarine environment. Despite the fact that other barnacles occur in this region, A. improvisus is the only species reported as an epibiont on Macrobrachium acanthurus; this was also the first record of epibiosis on this host. The occurrence of innumerable specimens in the pereiopods' articulations and the almost complete covering of the carapace of some prawns (which also increased their weight) suggest that A. improvisus is adapted to fixate this kind of biogenic substrate and that the relationship between the two species biologically damages the basibiont.O objetivo deste trabalho foi relatar a epibiose de cirrípedes Amphibalanus improvisus em oito camarões machos adultos da espécie Macrobrachium acanthurus provenientes da Laguna Mundaú, Alagoas, Brasil. O número de cirrípedes epibiontes variou desde 247 até 1.544 espécimes por camarão, distribuídos predominantemente no cefalotórax e pereiópodos, mas presentes também no abdome e demais apêndices. A grande maioria dos cirrípedes era recém-recrutada ou ainda estava sexualmente imatura, embora de alguns estivessem já em reprodução, sugerindo a chegada recente de seu hospedeiro no ambiente estuarino. Apesar de ocorrem outros cirrípedes na região, A. improvisus foi à única espécie relatada como epibionte em Macrobrachium acanthurus e isto se constituiu o primeiro registro de epibiose de Amphibalanus improvisus A ocorrência de inúmeros espécimes nas articulações dos pereiópodos e o recobrimento quase total da carapaça de alguns camarões (incrementando peso aos mesmos) indicam que a espécie epibionte está adaptada à fixação neste substrato biogênico e que a relação entre estas duas espécies traz prejuízos biológicos ao basibionte

Cirripedia of Madeira

We give a list of Cirripedia from Madeira Island and nearby deep water, based on specimens in the collection of the Museu Municipal do Funchal (Historia Natural) (MMF), records mentioned in the literature, and recent collections. Tesseropora atlantica Newman and Ross, 1976 is recorded from Madeira for the first time. The Megabalanus of Madeira is M. azoricus. There are 20 genera containing 27 species, of which 22 occur in depths less than 200 m. Of these shallow water species, eight are wide-ranging oceanic forms that attach to other organisms or to floating objects, leaving just 13 truly benthic shallow water barnacles. This low diversity is probably a consequence of the distance from the continental coasts and the small area of the available habitat. No endemic species have been found

Resident Benthic Fishes of Artificial Reefs in the Mississippi Sound: Effects of Habitat Relief and Subregion

One of the fundamental questions of artificial reef research concerns the capability of these manmade structures to promote secondary production. Many researchers have questioned whether artificial reefs increase the production of fish biomass, or simply aggregate existing fish biomass. Most previous research has focused on production of transient fish biomass, because of the high recreational and commercial value of these species. Establishing a link between transient fish production and artificial reef primary and secondary production has proved difficult. Therefore, the goal of this study was to examine the productivity of benthic fishes resident to artificial reefs in the Mississippi Sound, and to link this productivity to the artificial reef community through trophic relationships. This study examined differences in condition of benthic fishes resident to four artificial reefs of two profile types distributed across the Mississippi Sound. Poorer condition was found in several benthic fish species on concrete high profile reefs relative to low profile oyster shell reefs. Subregion also appeared to effect poorer condition in the eastern subregion. Diet volume was low in Gobiesox strumosus from high profile reefs, and contents differed across both reef types and subregions. Differences in diet contents may have been related to prey taxa tolerance of abiotic conditions and substrate type preferences. These results suggest reef material, design and abiotic conditions relating to specific reef location may affect availability or accessibility to specific prey taxa for resident fishes, and that this may in turn strongly affect production of biomass in resident fishes

18O fractionation in barnacle calcite: A barnacle paleotemperature equation

The calcitic shells of sessile barnacles (Balanomorpha) taken from ocean waters ranging in temperature from -2° to 26°C have a near constant 18O enrichment compared with mollusk values assumed to be at thermodynamic equilibrium…