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

Abstract

Paracaprellapusilla Mayer, 1890 is a tropical caprellid species recently introduced to the Eastern Atlantic coast of the Iberian Peninsula and the Mediterranean Sea. In this study, we used direct sequencing of mitochondrial (COI and 16S) and nuclear (28S and ITS) genes to compare genetic differences in presumed native and introduced populations in order to infer its introduction pattern and to shed light on the native range of this species. The temporal pattern of genetic diversity at the westernmost limit of the geographic range of P.pusilla in Europe (the Atlantic coast of southern Spain) over an eight-year period was also investigated. Our results confirm P.pusilla as a neocosmopolitan species and suggest that the species is native to the Atlantic coast of Central and South America. Paracaprellapusilla seems to have been introduced into European waters from multiple introduction pathways and source populations, which are likely to include populations from coastal waters of Brazil. Multiple introduction pathways may have been involved, with the most important being commercial shipping through the Strait of Gibraltar. While this tropical species appears to be expanding in the Mediterranean, populations from the westernmost limit of its geographic range in Europe showed a temporal instability. This study constitutes the first molecular approach focused on this species, but it is also the first study of temporal change in genetic diversity of any introduced marine amphipod. Additional intensive sampling of this species, including both native and non-native populations, and detailed temporal studies are still necessary to properly understand how genetic diversity influences the introduction and survival of P.pusilla in invaded areas.

An example for transatlantic hitchhiking by macrozoobenthic organisms with a research vessel

“…One of the most successful caprellid amphipod invaders on fouling substrates around the world (Paracaprella pusilla) has arrived in almost all parts of tropical, subtropical and temperate waters [32][33][34][35][36]. Previously it was mainly reported from subtropical and tropical waters [32].…”

Quick spreading of the exotic amphipod Laticorophium baconi (Shoemaker, 1934): another small stowaway overlooked?

“…This indicates that the species could potentially reach natural habitats in other introduced regions, as the Mediterranean, where the species is still restricted to artificial habitats. Other exotic amphipods in the Mediterranean, such as Stenothoe georgiana, Caprella scaura or Paracaprella pusilla, have not been established in natural environments so far, being confined to artificial habitats in the introduced range (Ros et al, 2014a;Cabezas et al, 2019;Martínez-Laiz et al, 2020), but it is worth noting that the level of biofouling NIS spreading in natural habitats is still poorly investigated. On the contrary, high densities of the exotic Jassa slatteryi have already been recorded in Mediterranean natural habitats, including marine protected areas (Navarro-Barranco et al, 2018, 2023.…”

“…Therefore, further molecular research is essential to understand the native range of L. baconi and to discard the possibility of a species complex of morphologically similar species. The molecular approach has proven invaluable in exploring the native ranges and invasion patterns of other marine amphipod species, such as Corophium volutator (Pallas, 1766) (Einfeldt & Addison, 2015), Caprella mutica Schurin, 1935 (Ashton et al, 2008), Caprella scaura (Cabezas et al, 2014), Paracaprella pusilla (Cabezas et al, 2019) or Jassa spp. (Beermann et al, 2020) among others.…”

Disentangling the Taxonomic Status of Caprella penantis sensu stricto (Amphipoda: Caprellidae) Using an Integrative Approach

“…PCR amplifications consisted of 25 µL reaction volumes containing 3 µL of template DNA, 10x buffer MgCl 2 free (Invitrogen, UK), 3 mM MgCl 2 , 0.2 mM dNTPs, 1 µM of each primer, 0.3 U Platinum Taq DNA polymerase (Invitrogen, UK) and double-distilled H 2 O to volume. PCR conditions used were as described in [53]. Furthermore, a 1051 bp fragment of the 18S ribosomal RNA (18S rRNA) nuclear gene was obtained for a subset of 24 individuals (Table 1), using the primers 18S-ai and 18S-bi [54] and following the PCR conditions specified by [29].…”