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Institute
Dragonflies from the Cape Verde Islands, collected between 1960 and 1989 and kept in institutes in Portugal and Cape Verde, were studied. The Cape Verde collection at the Centro de Zoologia, Instituto de Investigação Científica Tropical, Lisbon, Portugal, includes eight species of dragonflies represented by 279 specimens collected in 1960-61 and 1969-72. The entomological collection at the Instituto Nacional de Investigação e Desenvolvimento Agrário (INIDA), São Jorge dos Orgãos, Republic of Cape Verde, includes four odonate species, represented by 27 specimens, collected in the years 1987 and 1989. Anax tristis Hagen and A. rutherfordi McLachlan, single male specimens of which were collected in Santo Antão, 27 October 1972, are new taxa for the archipelago. Both are tropical migrants of which the nearest known occurrence in continental Africa is more than 1,000 and 1,500 km, respectively, from the Cape Verde Islands. The two collections contain several specimens from new localities within the archipelago, particularly from the islands of Maio and Fogo. Current knowledge of flight season and island distribution are summarized and updated.
Highlights
• Subcrustal earthquakes detected beneath Fogo volcano, Cape Verde.
• At the focal depth of 40 km temperatures are likely too high for brittle failure.
• The earthquakes may originate from magma injection into a deep subcrustal reservoir.
• This observation indicates a distinct magma supply system of Fogo volcano.
Abstract
Fogo volcano belongs to the Cape Verde hotspot and its most recent eruption occurred from November 2014 to February 2015. From January to December 2016 we operated a temporary seismic network and array on Fogo and were able to locate 289 earthquakes in total. Array analysis shows that most of the events occur within the crust at distances >25 km near the neighboring island of Brava. However, on 15th August 2016 the network recorded an isolated cluster of >20 earthquakes, 13 of which could be located beneath the southern part of Fogo. The differences between S- and P-wave arrival times at steep incidence clearly indicate focal depths between approximately 38 and 44 km whereas receiver-function analyses place the Moho discontinuity at depths between 11 and 14 km. Thus, the earthquakes are located well within the upper mantle directly beneath Fogo. In view of the elevated upper-mantle temperatures within a hotspot regime, we propose that fracturing induced by magmatic injection is the most likely cause for the observed deep earthquakes.
In the present paper three empidoid fly species new to science are described from the island Sal of the Cabo Verde archipelago. Aphrosylus salensis sp. nov., a marine dolichopodid fly, is found in the splash zone of a rocky sea shore. Crossopalpus salensis sp. nov. (Hybotidae) is recorded from two different sebkhas. Crossopalpus complicatus sp. nov. is reported from an irrigated wasteland. A key to the species of these two genera occurring on Cape Verde is provided. The presence of the morphospecies Tachytrechus tessellatus (Macquart, 1842), a presumed Old World tropical species, is confirmed.
The zoogeographic composition of the coastal ichthyofauna of the Cape Verde archipelago shows a predominance of Guinean species, followed by tropical-subtropical (amphi-Atlantic) fishes and several endemic species. Recent taxonomic revisions, new species descriptions, new fish records in the area and recent ecological surveys of intra-specific fish interaction as well as emergent research on seamounts in national waters warrant an up-to-date review of research on the ichthyofauna of Cape Verde. An updated percentage of endemic coastal reef fish of 10.2% attest significant speciation in Cape Verde waters. Almost half of the total cryptobenthic fish species richness in Cape Verde comprises endemic species, some of them newly discovered. Examples of endemism are discussed, notably white seabream Diplodus sargus lineatus, bulldog dentex Dentex (Virididentex) acromegalus, blackfish drummer Girella stuebeli, Lubbock's chromis Chromis lubbocki, Cape Verde damselfish Similiparma hermani and Guinean parrotfish Scarus hoefleri. Cape Verde diverges considerably from the other Macaronesian island groups in terms of its ichthyofauna and its uniqueness warrants special attention by governmental agencies and conservation organizations.
Loggerhead sea turtles Caretta caretta may now be the only species of marine turtle nesting on the island of Maio, Cape Verde Islands. Threats to loggerhead turtles include hunting of females on land and males and females in the water, poaching of nests and, increasingly, light pollution and other disturbances related to tourism development. Length and remoteness of the beaches on Maio lead to limited monitoring and data collection. Although it is believed that Maio has one of the largest nesting populations of loggerheads in the Cape Verde Islands, very little information exists regarding the nesting beaches and the population of nesting females. During July 2009, a four day survey of the island was carried out in order to obtain insight as to the status of nesting loggerheads on Maio. The census showed that compared to the island of Sal the number of turtles nesting on Maio was higher at 19.64% more nests and 39.9% more tracks during the same period. It is recommended that in order to determine the true size of the Maio nesting population a full census should be undertaken over several seasons.