Water bugs (Hemipera: Heteroptera: Nepomorpha & Gerromorpha) of Chile: phylogenetic and biogeographic considerations, and a catalog of the fauna

The Chilean fauna of water bugs comprises seven species of semi-aquatic bugs (Heteroptera: Gerromorpha), representing five genera, three tribes, four subfamilies and four families; and 27 species and one subspecies of aquatic bugs (Heteroptera: Nepomorpha), representing four subgenera, eight genera, three tribes, seven subfamilies, and five families. We compare the fauna with neighboring countries and find that several otherwise widespread and abundant taxa are missing in Chile, but that Chepuvelia usingeri China, 1963 (Macroveliidae), Microvelia chilena Drake & Hussey, 1955 (Veliidae), Limnocoris dubiosus Montandon, 1898 (Naucoridae), Nerthra (Nerthra) parvula (Signoret, 1863), N. (N.) undosa Nieser & Chen, 1992, N. (Rhinodermacoris) praecipua Todd, 1957 (Gelastocoridae), and Sigara (Tropocorixa) termasensis (Hungerford, 1928a) (Corixidae) are endemic to the country. To this list, we add †Nerthra (Nerthra) subantarctica Faúndez & Ashworth, 2015, even though the species is only known from a subfossil. We can also inform that while water bugs are found in the archipelagoes of southern Chile, no species has been reported from the Juan Fernandez Islands, Easter Island and other off-shore islands. Several of the Chilean species are without any close extant relatives, such as C. usingeri and Aquarius chilensis (Berg, 1881) (Gerridae), or with relatives in Oceania (N. praecipua), suggesting that historical events such as dispersal and extinction have had a major influence on the composition of the Chilean fauna.

Earthquakes Felt in the Juan Fernandez Islands: Where Are They Coming from?

The Juan Fernandez Islands (JFI) are located in the Pacific Ocean 675 km west of the Chilean coast. This archipelago has historically been affected by large tsunamis. Robinson Crusoe Island (RCI), the main island of the JFI, was first inhabited in 1749. Since then, several tsunamis have destroyed RCI port structures and sometimes caused deaths. Ground shaking perceived by the inhabitants has preceded some tsunami arrivals. Seismological instrumentation was temporarily deployed on RCI in 1999, and a permanent station has been operating since 2014. Here, we use these data to characterize the seismic waves that arrive at the JFI and to determine whether shaking perception could be used as a tsunami early warning system. We compute peak ground accelerations (PGAs) from P, S, and T waves generated by Peruvian and Chilean earthquakes and find that the largest ground shakings are mostly related to T‐wave arrivals, which correlate with macroseismic modified Mercalli intensities lower than III. From the analysis of PGAs and macroseismic intensities, we conclude that shaking perception can be associated with large megathrust earthquakes, subduction events generated in the deep zone of seismogenic contact, and local seismicity. Unfortunately, potential tsunami earthquakes that occur on the Chilean coast will not be felt on RCI. Consequently, ground shaking in the JFI would not be a good proxy for tsunami warning, and a robust tsunami early warning system is necessary for RCI.

Revision and phylogenetic analysis of the spider genus Philisca Simon (Araneae: Anyphaenidae, Amaurobioidinae)

We review the spider genus Philisca Simon, an endemic of the southern forests in Chile and Argentina, and present aphylogenetic analysis including 15 species, of which five are newly described (P. atrata, P. robinson, P. viernes, P. pizarroiand P. robusta), together with other 98 representatives of the family Anyphaenidae. Four species names are considerednomina dubia (Clubiona gayi Nicolet, Drassus mirandus Nicolet, Clubiona altiformis Nicolet, P. obscura Simon). Cluiliuschilensis Mello-Leitão is newly synonymized with P. accentifera Simon. The phylogenetic analysis resulted in P.puconensis Ramírez branching off basally in the genus, because of its numerous leg spines and unmodified malechelicerae, all plesiomorphic for the group; the remaining species form two clear groups. The first one, formed by P. hahniSimon, P. tripunctata (Nicolet), P. amoena (Simon), P. hyadesi (Simon) and P. doilu (Ramírez), are grouped by the lossof spines on legs I and II. The second, formed by P. huapi Ramírez, P. ingens Berland, P. ornata Berland, P. accentiferaSimon, P. atrata and four new species endemic to the Robinson Crusoe Island in the Juan Fernández Archipelago, havethe male chelicerae, and in most cases also the endites, modified. In total, six species of Philisca are endemic to JuanFernández, but our dataset is not conclusive for the distinction of alternative colonization scenarios. We analyze theevolution of leg macrosetae, and show two independent instances of reduction of spination, one on the continent and another on the Juan Fernández islands.