Long-distance dispersal, low connectivity and molecular evidence of a new cryptic species in the obligate rafter Caprella andreae Mayer, 1890 (Crustacea: Amphipoda: Caprellidae)

Abstract

The amphipod Caprella andreae Mayer, 1890 was recorded for the first time in Southern Iberian Peninsula (36°44 0 15 00 N, 3°59 0 38 00 W). This species is the only obligate rafter of the suborder Caprellidea and has been reported to attach not only to floating objects such as ropes or driftwoods but also to turtle carapaces. Mitochondrial and nuclear markers were used to examine dispersal capabilities and population genetic structure of C. andreae across seven localities in the Mediterranean and Atlantic Ocean collected from floating substrata with different dispersal patterns. The strong population differentiation with no haplotypes shared between populations suggests that C. andreae is quite faithful to the substratum on which it settles. In addition, the proportionally higher genetic diversity displayed in populations living on turtles as well as the presence of highly differentiated haplotypes in the same turtle population may be indicative that these populations survive longer, which could lead C. andreae to prefer turtles instead of floating objects to settle and disperse. Therefore, rafting on floating objects may be sporadic, and ocean currents would not be the most important factor shaping patterns of connectivity and population structure in this species. Furthermore, molecular phylogenetic analyses revealed the existence of a cryptic species whose estimates of genetic divergence are higher than those estimated between C. andreae and other congeneric species (e.g. Caprella dilatata and Caprella penantis). Discovery of cryptic species among widely distributed small marine invertebrates is quite common and, in this case, prompts for a more detailed phylogenetic analysis and taxonomic revision of genus Caprella. On the other hand, this study also means the first record of the gammarids Jassa cadetta and Elasmopus brasiliensis and the caprellid Caprella hirsuta on drifting objects.

Unravelling the origin and introduction pattern of the tropical species Paracaprella pusilla Mayer, 1890 (Crustacea, Amphipoda, Caprellidae) in temperate European waters: first molecular insights from a spatial and temporal perspective

“…Our results support the existence of one of the two main introduction pathways previously suggested by Ros and Guerra-García (2012) and Ros et al (2013b, c), that is, through the Strait of Gibraltar, from native populations of the Atlantic coast of America. Shipping routes have existed across the Atlantic for more than 500 years (Carlton 1989).…”

“…Unlike other caprellid taxa with a wide distribution, such as Caprella penantis (Cabezas et al 2013a) or C. andreae (Cabezas et al 2013b), the absence of population genetic structure ( Fig. 1; Suppl.…”

“…Two main pathways have been suggested for the introduction of P. pusilla to European waters. Ship fouling is the most probable vector for the introduction and dispersion of this species (Ros and Guerra-García 2012;Ros et al 2013b, c), either through the Strait of Gibraltar, from source populations in Central and South America, where it is supposedly native, or via the Suez Canal, from the Indo-Pacific. This second alternative is less likely because P. pusilla has not yet been found in the Red Sea (Zeina and Guerra-García 2016) and has only been reported once in the Suez Canal (Schellenberg 1928) despite recent studies (see El-Komi 1998; Emara and Belal 2004;Zeina and Guerra-García 2016).…”

Macaronesian islands as promoters of diversification in amphipods: The remarkable case of the family Hyalidae (Crustacea, Amphipoda)

“…Over the past decade, multiple genetic studies on marine amphipods have been reporting considerable levels of hidden or cryptic diversity (Cabezas, Navarro‐Barranco, Ros, & Guerra‐García, ; Radulovici, Sainte‐Marie, & Dufresne, ; Sotka, Bell, Hughes, Lowry, & Poore, ). Detected cases typically involve geographically distant populations or populations separated by obvious phylogeographic barriers.…”

Hitchhiking the high seas: Global genomics of rafting crabs

“…Caprella andreae, which like Planes is an obligate associate of surface-drifting oceanic flotsam and sea turtles, shows high diversity and cryptic speciation across a relatively small geographic area compared to Planes (Cabezas, Navarro-Barranco, Ros, & Guerra-García, 2012). Oceanic nudibranchs display different diversification patterns between sister species: Glaucus atlanticus is cosmopolitan and shows no evidence for cryptic diversification, while Glaucus marginatus is restricted to the Indo-Pacific and has diversified into four distinct lineages (Churchill, Alejandrino, Valdes, Foighil, & D., 2013).…”