Cladistic analysis of Dendryphantinae (Araneae: Salticidae)

Author(s)

Gustavo Rodrigo Sanches Ruiz

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Biociências (IBIOC/SB)
• Defense date: 2010-05-14

Examining board members

Antonio Domingos Brescovit; Antonio Carlos Marques; Fernando Portella de Luna Marques; Almir Rogério Pepato; Adalberto José dos Santos

• Advisor: Antonio Domingos Brescovit; Wayne Paul Maddison

Abstract

The subfamily Dendryphantinae includes many hundreds of species with a carina on the retrolateral surface of the male chelicerae and male palps with a reduced spiral embolus. Despite being one of the largest subfamilies of jumping spiders, dendryphantine lineages present an unusual morphological homogeneity across the entire group. The lack of diagnostic characters for genera has caused the indiscriminate proposal of many genera with loose boundaries. Because of that, current classification of the group is chaotic and needs to be revised under a phylogenetic scope. Since morphology is especially conservative in Dendryphantinae, molecular data are of extreme importance for phylogenetic reconstructions in the group. The main goal of this work was to sequence four gene regions the nuclear 28S and Actin and the mitochondrial 16S and ND1 of dendryphantines in order to reconstruct the phylogeny of the entire subfamily, allowing future revisions of its systematics and the understanding of such large biodiversity. During this study, we tried to sample as great a diversity of dendryphantine lineages, including almost all described genera, some problematic incertae sedis species and some lineages of undescribed species. We sampled over 85 dendryphantine species that had never been used in molecular studies. These taxa are mostly from South and Central America, but also from regions in the Old World, supplementing previously gathered molecular data from North American taxa. In addition to the dendryphantine terminals, we used 40 terminals as outgroups, limiting sampling to the large clade that includes the Astioida, Baviinae, Ballinae and Marpissoida. In total, analyses counted with 160 terminals. To root the trees, we used terminals of Astioida and Baviinae, in this order of preference, due to their close relationship to the Marpissoida + Ballinae clade. 11 Bayesian analyses were done using MrBayes (GTR+I+ model). Model parameters were permitted to differ among data partitions. We had two sets of partitions, one set with 8 and one set with 4 partitions. For the first set, we treated nuclear data independently from mitochondrial. For the second set of partitions, similar DNA types, nuclear or mitrochondrial, were treated as having similar evolution patterns. We also inferred trees using Maximum Parsimony for all the genes independently and for the same complete matrix used in the Bayesian analyses. Parsimony analyses were done using TNT, treating character states as unordered and gaps as missing data. As the result of the Bayesian analyses, the clades Ballinae, Marpissoida, Marpissinae, Synagelinae and Dendryphantinae were recovered as monophyletic. The general topology found by Maximum Parsimony for the All-Genes matrix agrees with the Bayesian analyses: (Astioida (Baviinae (Ballinae (Synagelinae (Marpissinae (Dendryphantinae)))))). Within the Dendryphantinae, the genus Hentzia Marx is the sister to the rest of the subfamily. Species of this genus, along with those of Anicius Chamberlin, Macaroeris Wunderlich, Phanias F.O.P.-Cambridge, Homalattus White, Mabellina Chickering and Rudra Peckham & Peckham, are the only groups of dendryphantines that have epiandrous fusules. The loss of these fusules characterizes a large clade that includes most dendryphantines. The clade of the infusulate dendryphantines includes three major lineages. The first is the genus Zygoballus Peckham & Peckham; the second, treated here as the Alcmenomorphs (nom. nov.), is a huge clade that includes Metaphidippus F.O.P.-Cambridge and several South American genera, such as Chirothecia Taczanowski, Ashtabula Peckham & Peckham, Lurio Simon, Alcmena C.L. 12 Koch and Admirala Peckham & Peckham; the third lineage, treated here as the Dendryphantomorphs (nom. nov.), includes the genera Ramboia Mello-Leitão, Parnaenus Peckham & Peckham, the Bagheera group (Bagheera Peckham & Peckham, Gastromicans Mello-Leitão, Selimus Peckham & Peckham and species of the Messua limbata group), the Bellota group (Bellota Peckham & Peckham, Paradamoetas Simon and Sassacus Peckham & Peckham, among other genera) and a huge clade from North America. The North American clade includes Ghelna Maddison, Terralonus Maddison, Dendryphantes C.L. Koch, Tutelina Simon, Phidippus C.L. Koch, Paraphidippus F.O.P.-Cambridge, Beata Peckham & Peckham, Eris C.L. Koch, Nagaina Peckham & Peckham and Pelegrina Franganillo. Despite the fact that the subfamily seems to be a group originated on the American continent, where it presents a great diversification, dendryphantines have reached the Old World at least three times independently. Two of these invasions are probably older and were carried out by lineages with epiandrous fusules, namely Macaroeris and Homalattus (former Rhene Thorell), while the third seems to be a very recent invasion by an infusulate group, the genus Dendryphantes, who still has members in North America. Besides biogeographical studies, many other aspects of their evolution can be inferred based on this topology, such as the evolution of sexual secondary dimorphism (e.g. the chelicerae), mimicry (beetles/ants) or the evolution of male palp/epigynum structures. Based on this phylogenetic hypothesis, we will be able to revise natural groups of genera with criticism, allowing their taxonomic simplification and easier recognition. We hope that this work increases the interest of other arachnologists on the group and propitiates the description of the several hundred new species that remain unknown and unnamed. (AU)

• FAPESP's process: 06/55226-0 - Cladistic analysis of Dendryphantinae (Araneae: Salticidae)
• Grantee: Gustavo Rodrigo Sanches Ruiz
• Support Opportunities: Scholarships in Brazil - Doctorate