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The commensals on Chilean Decapoda of inland waters are characterized by a marked microendemism. The aim of the present study was to do an exhaustive review on the ectocommensals on Chilean inland-water decapods. The literature revealed the presence of species of Protozoa, viz., eight known only from Parastacus pugnax (Lagenophrys andos, Operculigera insolita, O. parastacis, O. seticola, O. striata, O. taura, Chilenophrys allendei, and Circolagenophrys shiftus), one for both P. pugnax and P. nicoletti (L. anticthos), one for Parastacus pugnax and Samastacus spinifrons (O. asymmetrica), and one reported for Aegla laevis (O. velata). In addition, the presence of flatworms was described, specifically Temnocephala chilensis, associated with A. laevis, P. pugnax, and S. spinifrons, and species of Polychaeta, i.e., Stratiodrilus platensis associated with A. abtao and A. bahamondei, S. aeglaphilus for A. laevis, and S. pugnaxi for P. nicoletti. Biogeographical, ecological and taxonomic implications are discussed.

The distributional patterns of the species of the South American freshwater crayfishes of the family Parastacidae were analysed using panbiogeographical track analyses to identify targeted regions of crayfish biodiversity for understanding biogeographical patterns. Two generalized tracks were identified using the track analysis approach: (1) Uruguay and Brazil (Parastacus brasiliensis, P. brasiliensis promatensis, P. buckupi, P. caeruleodactylus, P. defossus, P. fluviatilis, P. gomesae, P. guapo, P. macanudo, P. pilimanus, P. pilicarpus, P. saffordi, P. tuerkayi, P. varicosus); and (2) Central-southern Chile (P. nicoleti, P. pugnax, Samastacus spinifrons, Virilastacus araucanius, V. jarai, V. retamali and V. rucapihuelensis). These areas were exclusive, with no overlap between them. The results indicate the presence of South American Parastacidae crayfish in Atlantic coastal sub-tropical and Pacific coastal temperate wet climate regions with biogeographic similarities to other South American inland water decapods.

The crayfishes of Chile are endemic species and have been poorly studied with respect to their biology. The available literature is restricted to species descriptions, whereas there is no information about other biological topics such as ectocommensals and parasites, which can affect crayfishes. The aim of the present study was to do a literature review and update the information about ectocommensals and parasites that have been reported from Chilean crayfishes. The literature mentioned the presence of Temnocephala chilensis (Platyhelminthes), Stratiodrilus pugnaxi (Polychaeta) and Protozoa such as species of the genera Operculigera and Lagenophrys as ectocommensals for Parastacus pugnax and Samastacus spinifrons. As an endoparasite, Psorospermium haeckelii was reported, a unicellular eukaryotic organism that was found in P. pugnax ovaria. An additional analysis of collected specimens of P. pugnax and S. spinifrons revealed the presence of T. chilensis, albeit at a low incidence. Ecological, biogeographical and evolutionary topics are discussed considering the case of a marked microendemism of an organism associated with Chilean crayfishes.

The Chilean north Patagonian lakes are characterized by their marked oligotrophic or oligomesotrophic status and low abundance of zooplankton species; many of the lakes with oligomesotrophic status are associated with human intervention due to towns on their shores. The aim of the present study was to determine the relations between spectral properties (LANDSAT OLI), chlorophyll and plankton abundances in two north Patagonian lakes: Villarrica, which has two towns on its shores, and Lake Caburgua, which has native forest on its shores. The results revealed that Lake Villarrica has high reflectance in the near infrared, red and green bands, high concentrations of chlorophyll a, the absence of mixotrophic protozoa, and a high abundance of bacterial and plankton, mainly phytoplankton (Chlophyceae and diatoms) and zooplankton. Lake Caburgua, on the other hand, has low reflectance in the same bands, and low chlorophyll concentrations, low bacterial and zooplankton abundances, with the exception of high mixotrophic ciliates and small phytoplankton, and Volvox colonies. The obtained results agree with limnological observations on both lakes, and observations agrees with similar observations of the spectral properties of glacial north Patagonian lakes and of the zooplankton community, and in this scenario, the use of remote-sensing techniques would be a good tool to predict the plankton community in Patagonian lakes.

Antofagasta Bay is characterized by having a high primary productivity due to the presence of the cold Humboldt Stream. However, due to the current global climate change, also the previously generated biodiversity patterns are changing. The aim of the present study was analysing Antofagasta Bay in order to determine the existence of correlations between optical, i.e., spectral, properties recorded through remote sensing on the one hand, and the presence of dinoflagellates and zooplankton, on the other. The studies were done during two periods, i.e., in February 2019 and February 2020. The results revealed the existence of three main groups of sites: a first group comprising sites sampled in February 2019, with high Band 3 and Band 4 reflectance, high chlorophyl values, and high abundances of Dinophysis and copepods; a second group combining four sites visited in February 2019, with high Gymnodinium and Ceratium, high reflectance in Band 1, Band 2, Band 5, Band 6 and Band 7, and low zooplankton abundance; and finally a third group encompassing all sites sampled in 2020, with high Prorocentrum abundance, and low zooplankton abundance, as well as low reflectance. A similar situation with regard to zooplankton and optical properties was earlier reported for Chilean Patagonian lakes.

Antofagasta Bay is characterized by a high primary productivity due to the presence of the cold Humboldt Stream that is associated with a high diversity in flora and fauna in the benthic and pelagial environments of the Chilean west coast. Nevertheless, due to the global climate changes, the existing biodiversity patterns change as well. The aim of the present study was to analyse Antofagasta Bay for determining the existence of patterns between optical properties of the water, and the phytoplankton and zooplankton. The results show that one site had high chlorophyll concentrations, high reflectance, a high abundance of the dinoflagellate genus Dinophysis, and a high abundance of copepodites, whereas five sites had low chlorophyll concentrations, a low reflectance value, low copepodite abundances, and high abundances of dinoflagellates of the genera Ceratium, Gymnodinium and Prorocentrum. These results are similar to earlier observations for the coastal waters along northern Chile.