Latitudinal distribution of skeleton shrimps (Amphipoda, Caprellidae) in artificial habitats throughout the eastern South Pacific coast of Peru

ABSTRACT Biodiversity tends to decrease poleward and increase towards the equator. However, these patterns remain unknown for many invertebrate taxa throughout Peru's eastern South Pacific coast, particularly for caprellid crustaceans which are conspicuous in artificial habitats. Three biogeographical units have been proposed for the Peruvian coast: Panamic and Humboldt provinces with a transition zone in between, but a few invertebrates support this classification. We evaluated if the diversity of caprellids decreases towards high latitudes and if the assemblages of caprellids depicted the biogeographic zonation proposed for the Peruvian coast. From 15th to 31st October 2021, caprellids were collected from biofouling communities colonizing boat hulls, buoys, and ropes throughout the Peruvian coast (3.74°–17.99° S). The caprellid assemblage consisted on six species: Caprella penantis [sensu lato], C. penantis f. gibbosa, C. equilibra, C. scaura, Paracaprella pusilla, and Deutella venenosa. Overall, caprellids' abundance, species richness, and diversity decreased southwards. Specific caprellid assemblages showed affinities for each of the three biogeographical units. The dissimilarity of the caprellid assemblages increased at approximately every one degree of latitude. Although artificial substrates can alter biodiversity patterns, caprellids showed the canonical pattern of high diversity towards the equator and resembled the biogeographic zonation proposed for the Peruvian coast.