Falklands: Facts and fiction

A reply to McDowall, R.M. (2005) Falkland Islands biogeography: converging trajectories in the South Atlantic Ocean. Journal of Biogeography, 32, 49–62. A recent contribution (McDowall, 2005) analysed the biogeography of the Falkland Islands, an archipelago situated in the south‐western Atlantic, known in Spanish as Islas Malvinas. After reviewing the literature, McDowall (2005) concluded that the biotic and geological connections of the Falklands conflict with each other because the biota shows apparent relationships with Patagonia, whereas the geology suggests a historical relationship with South Africa. He considered that these results indicate that Croizat's dictum that ‘earth and life evolve together’‘does not have general application in the way that some believe it has’ (McDowall, 2005, p. 59), thus ruling out vicariance as an appropriate explanation for the evolution of the Falklands’ biota.Fil: Morrone, Juan José. Universidad Nacional Autónoma de México; MéxicoFil: Posadas, Paula Elena. Museo Paleontológico Egidio Feruglio; Argentin

Cladistics and biogeography of the assassin bug genus Rasahus Amyot & Serville (Heteroptera: Reduviidae: Peiratinae)

The assassin bug genus Rasahus Amyot & Serville (Heteroptera: Reduviidae: Peiratinae) comprises 26 Neotropical species. A cladistic analysis of the genus was carried out using 63 characters from external morphology, body vestiture, and male and female genitalia, with the species considered as terminal taxa. The analysis yielded 149 equally parsimonious cladograms, each with 206 steps, CI = 0.35, and RI = 0.60; the successive weighting procedure resulted in eight cladograms (CI = 0.79 and RI = 0.91). In the strict consensus cladogram, two major clades are delimited: one comprising the species R. rufiventris, R. hamatus, R. arcitenens, R. arcuiger, R. amapaensis, R. thoracicus, R. biguttatus, R. argentinensis, R. limai, R. grandis, and R. angulatus; and the other with R. castaneus, R. aeneus, R. scutellaris, R. maculipennis, R. brasiliensis, R. sulcicollis, R. surinamensis, R. albomaculatus, R. guttatipennis, R. atratus, R. peruensis, R. costarricensis, R. bifurcatus, R. flavovittatus, and R. paraguayensis. A cladistic biogeographic analysis of the provinces of the Neotropical subregion, considering distributional data of the species of Rasahus and three other genera of Peiratinae (Eidmannia, Melanolestes, and Thymbreus) was carried out. Four general area cladograms were obtained applying programs COMPONENT 2.0 and TASS. The most parsimonious general area cladogram (= implying fewer items of error) was obtained with COMPONENT 2.0 minimizing the number of leaves added, and shows the sequence (Desierto, (Caatinga, (Cerrado, (Chacoan, (Caribbean, Amazonian), (Paranaense, Atlantic))))). This sequence of area relationships is congruent with the history previously hypothesized for the subregion, where the development of an open vegetated diagonal (comprising the Chacoan, Cerrado, and Caatinga provinces) due to the aridification induced by the gradual uplift of the Andes, separated the former Amazonian forest in a northwestern part (Caribbean plus Amazonian provinces) and a southeastern part (Paranaense plus Atlantic provinces)

Distributional patterns of the American Peiratinae (Heteroptera: Reduviidae)

Based on distributional data of 40 species of Peiratinae, historical relationships of five Amazonian areas (Paranaense, Atlantic, Pacific, Amazonian, and Cerrado) and two Chacoan areas (Chaco and Caatinga), were investigated through a parsimony analysis of endemicity (PAE). The resulting area cladogram indicates the following sequence of area fragmentation: (Cerrado (Caatinga (Chaco, ((Pacific, Amazonian), (Atlantic, Paranaense))))). It is proposed that these results reflect the gradual development of a diagonal of open formations (Chaco-Cerrado-Caatinga), which separated the former continuous tropical forest into two parts, namely, northwestern (Pacific plus Amazonian) and southeastern (Paranaense plus Atlantic)