Phylogeny of coral-inhabiting barnacles (Cirripedia; Thoracica; Pyrgomatidae) based on 12S, 16S and 18S rDNA analysis.
ABSTRACT The traditional phylogeny of the coral-inhabiting barnacles, the Pyrgomatidae, is based on morphological characteristics, mainly of the hard parts. It has been difficult to establish the phylogenetic relationships among Pyrgomatidae because of the apparent convergence of morphological characteristics, and due to the use of non-cladistic systematics, which emphasize ancestor-descendant relationships rather than sister-clade relationships. We used partial sequences of two mithochondrial genes, 12S rDNA and 16S rDNA, and a nuclear gene, 18S rDNA, to infer the molecular phylogeny of the pyrgomatids. Our phylogenetic results allowed us to reject previous classifications of Pyrgomatidae based on morphological characteristics. Our results also suggested the possibility of paraphyly of the Pyrgomatidae. The hydrocoral barnacle Wanella is not found on the same clade as the other pyrgomatids, but rather, with the free-living balanids. The basal position of Megatrema and Ceratoconcha is supported. The archeaobalanid Armatobalanus is grouped with Cantellius at the base of the Indo-Pacific pyrgomatines. Fusion of the shell plate and modification of the opercular valves are homoplasious features that occurred more than three times on different clades. The monophyly of the "Savignium" group, comprising four nominal genera, is also not supported, and the different taxa are placed on different clades.
Full-textDOI: · Available from: Noa Simon-Blecher, May 27, 2015
SourceAvailable from: Marcos Pérez-Losada[Show abstract] [Hide abstract]
ABSTRACT: The Balanomorpha are the largest group of barnacles and rank among the most diverse, commonly encountered and ecologically important marine crustaceans in the world. Paradoxically, despite their relevance and extensive study for over 150 years, their evolutionary relationships are still unresolved. Classical morphological systematics was often based on non-cladistic approaches, while modern phylogenetic studies suffer from severe undersampling of taxa and characters (both molecular and morphological). Here we present a phylogenetic analysis of the familial relationships within the Balanomorpha. We estimate divergence times and examine morphological diversity based on five genes, 156 specimens, ten fossil calibrations, and six key morphological characters. Two balanomorphan superfamilies, eight families and twelve genera were identified as polyphyletic. Chthamaloids, chionelasmatoid and pachylasmatoids split first from the pedunculated ancestors followed by a clade of tetraclitoids and coronuloids, and most of the balanoids. The Balanomorpha split from the Verrucidae (outgroup) in the Lower Cretaceous (139.6 Mya) with all the main lineages, except Pachylasmatoidea, having emerged by the Paleocene (60.9 Mya). Various degrees of convergence were observed in all the assessed morphological characters except the maxillipeds, which suggests that classical interpretations of balanomorphan morphological evolution need to be revised and reinterpreted.Molecular Phylogenetics and Evolution 09/2014; 81. DOI:10.1016/j.ympev.2014.09.013 · 4.02 Impact Factor
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ABSTRACT: Identification of marine invertebrate larvae using morphological characters is laborious and complicated by phenotypic plas-ticity. Balanus amphitrite is a dominant barnacle, important in the context of intertidal ecology and biofouling of manmade structures. Morphological identification of barnacle larval forms in a mixed population is difficult because of their intricacy and similarity in size, shape and developmental stages. We report the development and application of a nucleic acid-based Polymerase Chain Reaction (PCR) method for the specific identification of the barnacle, B. amphitrite, from the heteroge-neous zooplankton sample. This method is reliable and accurate thereby overcoming taxonomic ambiguity. Sequence align-ment of the 18S rRNA gene region of selected species of barnacles allowed the design of B. amphitrite-specific PCR primers. Assay specificity was evaluated by screening DNA obtained from selected species of barnacles. The oligonucleotide primers used in the study flanked a 1600 bp region within the 18S rRNA gene. The primer is specific and can detect as few as 10 indi-viduals of B. amphitrite larvae spiked in a background of 186 mg of zooplankton. This technique facilitates accurate iden-tification and the primer can be used as a marker for enumeration of B. amphitrite larvae in the plankton. Larval ecology studies help in understanding the population dynamics, community patterns, ecosystem structure and bio-diversity of native and invasive species (Webb et al., 2006). Identification of marine invertebrate larvae is a tedious, labour intensive task by expert taxonomists. Traditionally, planktonic larval identification is difficult because of larval intricacy and similarity in size, shape and developmental stages (Chanley & Andrews, 1971; Branscomb & Vedder, 1982; Shanks, 1986; Nichols & Black, 1994). Due to their small size, shape and similar developmental stages, it is diffi-cult to identify these larvae morphologically, although they play a pivotal role in taxonomic identification (Levin, 1990). Sometimes larval identification becomes extremely difficult due to phenotypic plasticity (Hebert, 2002). Molecular techniques have the potential to accurately iden-tify the organism to its species level, thereby overcoming taxo-nomic ambiguity. Identification and quantification of marine invertebrate larvae is far easier using molecular techniques (Baldwin et al., 1996; Bilodeau et al., 1999; Makinster et al., 1999; Morgan & Rogers, 2001; Deagle et al., 2003; Larsen et al., 2005; Vadopalas et al., 2006; Jones et al., 2008; Chen et al., 2013). Polymerase Chain Reaction (PCR) along with sequencing has led to accurate identification of any organism to its species level. Appropriate use of specific primers can facilitate rapid, sensitive and accurate detection of any individ-ual species in a population. Some molecular techniques which assist in identification or characterization of organisms are DNA barcoding (Hebert et al., 2003a, b); Random amplified polymorphic DNA (Coffroth & Mulawka, 1995); multiplex PCR (Hare et al., 2000); Middle repetitive sequence analysis (MaKinster et al., 1999); Amplified fragment length poly-morphism (Bucklin, 2000; Rogers, 2001); Restriction fragment length polymorphism and Single strand conformation poly-morphism analysis (Hillis et al., 1996). Oligonucleotide probes used for specific detection of individual larvae in a mixed population are either concise to family level (Bell & Grassle, 1998), genus level (Frischer et al., 2000) or species level (Frischer et al., 2000; Hare et al., 2000). Molecular tools with respect to PCR-based approaches are more reliable and frequently used in larval identification (Hare et al., 2000; Wood et al., 2003; Webb et al., 2006; Chen et al., 2013). Barnacles are of major concern in biofouling studies around the world. They have drawn the attention of many investigators in marine plankton ecology owing to their easy accessibility on the rocky intertidal regions and also because some species are dominant in marine fouling (Strathmann et al., Thiyagarajan et al., 1997a, b). Barnacles possess both a plank-totrophic and a lecithotropic larval stage, which settle and metamorphose on hard substratum resulting in macrofouling. Morphological identification of barnacle larval forms in a population is difficult because of their intricacy and similarityJournal of the Marine Biological Association of the UK 05/2015; 95(03):497-502. DOI:10.1017/S0025315414001581 · 1.13 Impact Factor
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ABSTRACT: A number of stylasterid corals are known to act as host species and create refuges for a variety of mobile and sessile organisms, which enhances their habitat complexity. These include annelids, anthozoans, cirripeds, copepods, cyanobacteria, echinoderms, gastropods, hydroids and sponges. Here we report the first evidence of a diverse association between stylasterids and scalpellid pedunculate barnacles and describe a new stylasterid species, Errina labrosa, from the Tristan da Cunha Archipelago. Overall, five stylasterid species are found to host eight scalpellid barnacles from several biogeographic regions in the southern hemisphere (Southern Ocean, temperate South America and the southern Indo-Pacific realms). There is an apparent lack of specificity in this kind of association and different grades of reaction to the symbiosis have been observed in the coral. These records suggest that the association between pedunculate barnacles and hard stylasterid corals has a wide distribution among different biogeographic realms and that it is relatively rare and confined largely to deep water.ZooKeys 01/2015; 472(472). DOI:10.3897/zookeys.472.8547 · 0.92 Impact Factor