Molecular systematics of basal subfamilies of ants using 28S rRNA (Hymenoptera: Formicidae)

Abstract

For many years, the ant subfamily Ponerinae was hypothesized to contain the basal (early branching) lineages of ants. Recently the Ponerinae were reclassiWed into six poneromorph subfamilies based on morphological analysis. We evaluate this new poneromorph classiWcation using 1240 base pairs of DNA sequence data obtained from 28S rRNA gene sequences of 68 terminal taxa. The molecular tree supported the monophyly of the ant family Formicidae, with 100% parsimony bootstrap (PB) support and posterior probabilities (PP) of 1.00, with the ant subfamily Leptanillinae as a sister group to all other ants (PB D 62, PP D 93). However, our analyses strongly support the polyphyly of the Poneromorph subfamilies (sensu Bolton). The Ectatomminae and Heteroponerinae are more closely related to the Formicoid subfamilies than to the rest of the poneromophs (PB D 96, PP D 100). The Amblyoponinae (PB D 52, PP D 96), Paraponerinae (PB D 100, PP D 100), Ponerinae (PB < 50, PP D 71), and Proceratiinae (PB D 98, PP D 100) appear as distinct lineages at the base of the tree and are identiWed as a poneroid grade. Monophyletic origins for the poneroid subfamilies Amblyoponinae, Paraponerinae, Ponerinae and Proceratiinae are supported in our analysis. However, the genus Platythyrea forms a distinct sister group to the Ponerini within the Ponerinae. The Heteroponerinae, based on our sample of Heteroponera, are associated with the subfamily Ectatomminae (PB D 98, PP D 100). Furthermore, our data indicate the genus Probolomyrmex belongs to the Proceratiinae as suggested by recent morphological analysis (PB 98, PP 100).

Evaluating alternative hypotheses for the early evolution and diversification of ants

“…To provide directionality to this unrooted tree, we compared a range of alternative root positions by attaching the outgroups to different branches based on a priori hypotheses from the literature and evaluating these alternatives within a likelihood framework. Rooting 1 corresponds to Leptanillinae as the sister group to all other ants, the prior hypothesis suggested by previous molecular work (17,20,21). Rooting 2 implies the monophyly of (Amblyoponinae plus Leptanillinae plus Tatuidris), an alternative topology consistent with evidence of shared morphological (18,26) and behavioral features between Amblyoponinae and Leptanillinae, including adult consumption of larval hemolymph and the use of geochilomorph centipedes as prey (6,19,(27)(28)(29)(30).…”

“…This interpretation is contradicted by several molecular divergence dating studies that consistently estimate older ages for ants (14)(15)(16)(17). Molecular data have also generated some surprising phylogenetic results, including the conclusion that the subfamily Leptanillinae, a group of specialized subterranean predators (18,19), is the sister group to the rest of the ants (17,20,21). This conclusion contradicts all previous hypotheses about ant relationships.…”

A Phylogenetic Analysis of Ant Morphology (Hymenoptera: Formicidae) with Special Reference to the Poneromorph Subfamilies

“…In addition, phylogenetic analyses have shown that different groups of genera formally within Ponerinae s.l. are more closely related to other subfamilies than among themselves (Keller, 2000;Ward and Brady, 2003;Saux et al, 2004;Brady et al, 2006;Moreau et al, 2006;Ouellette et al, 2006). Such accumulation of evidence led Bolton (2003) to propose the elevation of the major tribes within the old assembly to subfamily status, hence splitting the group into six subfamilies and restricting the name Ponerinae to the subgroup of genera mostly corresponding to the previously recognized tribe Ponerini.…”

“…KELLER: PHYLOGENETIC ANALYSIS OF ANT MORPHOLOGY Brady et al, 2006;Moreau et al, 2006;Ouellette et al, 2006), with analyses sampling several nuclear and mitochondrial gene regions for all recognized extant subfamilies or specific large portions of the ant phylogenetic tree. In contrast, comprehensive morphological data sets above the genus level have only been compiled for the dorylomorphs , Pseudomyrmecinae (Ward, 2001;Ward and Downie, 2005), and Myrmeciinae (Ward and Brady, 2003).…”

A comparison between time of exposure, number of pitfall traps and the sampling cost to capture ground-dwelling poneromorph ants (Hymenoptera: Formicidae)

“…These ants are distributed throughout the world's zoogeographic regions and occupy a great diversity of ecological niches, from both small and cryptic, to large and remarkable (Ouellette et al, 2006). The poneromorph ants have a great ecological importance, occupying different trophic levels (Brandão et al, 2011), thus participating in mutualistic plant associations (Pereira et al, 2013), facilitating seed dispersal (Leal et al, 2014).…”