Historical relationships among areas of endemism in the tropical South America using Brooks Parsimony Analysis (BPA)

Abstract

Areas of endemism are the smallest units of biogeographical analysis. One of its definitions is that these areas harbor organisms with restricted distributions caused by non random historical factors. The aim of this study was to examine historical relationships among areas of endemism in the Neotropics using Brooks Parsimony Analysis (BPA). We applied BPA to 12 unrelated taxa distributed within two sets of endemic areas in order to: (1) compare the proposed endemic area classifications; (2) examine whether Amazonia and Atlantic Forest are true biogeographic units and, (3) examine whether the inclusion of open area formations influence area relationships of the surrounding forests. General area cladograms revealed a basal split between Amazonian and Atlantic forests, suggesting that these areas have been isolated for a long period of time. All Atlantic forest endemic areas formed a monophyletic cluster, showing a sequence of vicariant events from north to south. The hypothesis that Amazonia is a composite area, made up of different historical units, is herein corroborated. When Cerrado and Caatinga (grasslands and savannas) are included, internal area relationships within Amazonia change, indicating that area classification schemes comprising forests and open formations should be preferred given the complementary history of these areas.

Historical relationships among Neotropical endemic areas based on Sepedonea (Diptera: Sciomyzidae) phylogenetic and distribution data

“…The complexities include, for example, widespread taxa and missing areas due to extinction. Thus BPA, along with many other methods, does indeed have the cited shortcoming, and the area relationships presented here should be treated as preliminary results that can be further tested using different approaches of cladistic biogeography (SIGRIST & CARVALHO 2009).…”

“…The BPA's were performed using the area sets previously described by SIGRIST & CARVALHO (2009). The first analysis used the inner subdivisions of Southeast and Northwest components of AMORIM & PIRES (1996) (Figs 2 and 3) in an attempt to test the monophyly of the Atlantic Forest.…”

“…The first analysis used the inner subdivisions of Southeast and Northwest components of AMORIM & PIRES (1996) (Figs 2 and 3) in an attempt to test the monophyly of the Atlantic Forest. An area named Venezuela/Colombia (Ven/Col) was included in this analysis because some distributions were present there (SIGRIST & CARVALHO 2009 …”

“…The use of forested areas associated with intervening savanas forests or open grasslands allows to test the influence of these unrelated biomes (open vegetation) on the humid areas relationships (SIGRIST & CARVALHO 2009). Given that Sepedonea flies inhabit humid environments and are distributed within this area in open vegetation areas (FREIDBERG et al 1991), they are excellent organisms for this investigation proposal.…”

“…Another aspect investigated was the monophyly of Amazonian and Atlantic forests. The high biodiversity found in these biomes has been the topic of a series of debates in the literature, and these have questioned whether the two areas are biogeographical units or not (AMORIM & PIRES 1996, NIHEI & CARVALHO 2007, SIGRIST & CARVALHO 2009). The results we obtained from our analysis enabled us to present some conclusions regarding the evolutionary history of the Neotropical region.…”