Genetic divergence of tanaidaceans (Crustacea: Peracarida) with low dispersal ability

Abstract

Summary:In this study, the phylogeographic patterns of nuclear, ribosomal and mtDNA gene fragments of five tanaidacean species (Zeuxo, Tanaidae) from the Atlantic, Pacific and Mediterranean Sea were investigated. We aimed to interpret results in the framework of current hypotheses on the distribution of small invertebrates with very limited dispersal ability. Evidence for a surprisingly high genetic divergence was found for intertidal tanaidaceans from the North Atlantic. This is a result of poor dispersal potential, as tanaidaceans have direct development, no pelagic stage, and very limited swimming capacity. However, lower genetic divergence was found between an intertidal tanaid species from the North Atlantic and two from the North Pacific, which suggests a scenario of recent colonization following the last glacial maximum. The species Zeuxo normani was found to be a species complex consisting, at least, of Z. normani (California), Z. cf. normani (Japan), Z. cf. normani (Australia), Z. sp. A (Korea), and Z. holdichi (Spain and France). Our results showed that traditional species identification underestimates tanaidacean diversity and that what have been previously perceived as reliable diagnostic morphological characters, are, however, variable and unreliable.Keywords: genetic divergence; morphological differences; 28S; H3; COI; Crustacea; Tanaidacea; Zeuxo. Divergencia genética de tanaidáceos (Crustacea: Peracarida) con baja capacidad de dispersiónResumen: En este estudio, investigamos los patrones filogeográficos de fragmentos de ADN nuclear, ribosómico y mitocondrial de 5 especies de tanaidáceos (Zeuxo, Tanaidae) del Atlántico, Pacífico y Mediterráneo. Nos propusimos interpretar los resultados en el marco de hipótesis sobre la distribución de pequeños invertebrados con limitada capacidad de dispersión. Encontramos evidencia de una sorprendentemente alta diferenciación genética para tanaidáceos del medio intermareal del Atlántico Norte. Esto es resultado de una limitada capacidad de dispersión, ya que los tanaidáceos poseen desarrollo directo, carecen de estadíos pelágicos, y una limitada capacidad natatoria. Sin embargo, encontramos una baja diferenciación genética para una especie de tanaidáceo del Atlántico Norte y dos del Pacífico Norte, lo que sugiere un escenario de reciente colonización tras la última glaciación. La especie Zeuxo normani constituye un complejo de especies que, al menos, agrupa a Z. normani (Califonia), Z. cf. normani (Japón), Z. cf. normani (Australia), Z. sp. A (Corea) y Z. holdichi (España y Francia). Nuestros resultados mostraron que la forma tradicional de identificar tanaidáceos subestima su diversidad y que lo que previamente se consideraron como caracteres morfológicos claramente diferenciadores son, sin embargo, variables y poco fiables.Palabras clave: diferencias genéticas; diferencias morfológicas; 28S; COI; crustáceos, tanaidáceos, Zeuxo.Citation/Como citar este artículo: Larsen K., Tuya F., Froufe E. 2014. Genetic divergence of tanaidaceans (Crustacea: Peracarida) with l...

New species of the genus Zeuxo (Peracarida, Tanaidacea)

“…Individuals belonging to this genus, however, are very difficult or impossible to identify without dissection of mouthparts (Sieg, 1980) which requires extensive taxonomic expertise. At the same time, what were initially thought to be defining characters for species, and even for higher level identifications, such as the number of uropodal articles and pleopodal setation have been shown to vary within both species (KudinovaPasternak, 1989;Bamber, 1990) and individuals (Larsen et al, 2014). This has also been shown in other tanaidomorphans (Masunari, 1983;Larsen & Wilson, 1998;Larsen, 2006;Bird, 2008;Larsen et al, 2012;Larsen & Froufe, 2013).…”

Comparison of life history traits of Tanais dulongii (Tanaidacea: Tanaididae) in natural and artificial marine environments of the south-western Atlantic

“…a likely introduced organism) (Orensanz et al 2002). According to Poore (1996), this wide distribution is highly suspect due to some tanaidaceans are superficially similar favouring a taxonomic misidentification, so most researchers are convinced that T. dulongii is a species complex consisting of several species morphologically similar as has been shown for many other tanaidaceans (Bamber, 2012;Larsen et al, 2014). However, this assertion has not been verified yet due to the lack of genetic studies.…”

Redescription of wood-associated tanaidacean Protanais birsteini (Kudinova-Pasternak, 1970) and its relationship within the Tanaididae

“…The sequence of P. birsteini was compared to a recently obtained database of tanaidacean COI sequences collected from the waters around Iceland (manuscript in prep), augmented with all sequences for Tanaididae available from GenBank (several of which were recently published by Larsen et al, 2014); these consisted of T. dulongii (Audouin, 1826), Zeuxo exsargasso Sieg, 1980, Z. holdichi Bamber, 1990, Z. normani (Richardson, 1905, and Zeuxo sp. With Sphyrapodidae from the Icelandic collection (unpublished data) and Kalliapseudidae from Drumm and Kreiser (2012) obtained from GenBank as outgroups, this dataset was used to estimate Bayesian and maximum likelihood trees, trimming all sequences to the length of those of Larsen et al (2014) (approx.…”

“…With Sphyrapodidae from the Icelandic collection (unpublished data) and Kalliapseudidae from Drumm and Kreiser (2012) obtained from GenBank as outgroups, this dataset was used to estimate Bayesian and maximum likelihood trees, trimming all sequences to the length of those of Larsen et al (2014) (approx. 400 bp).…”