An unexpected clade of South American ground beetles (Coleoptera, Carabidae, Bembidion).

David Maddison

doi:10.3897/zookeys.416.7706

Abstract

Phylogenetic relationships of the Antiperyphanes Complex of the genus Bembidion are inferred using DNA sequences from seven genes (two nuclear ribosomal, four nuclear protein coding, and one mitochondrial protein coding). Redefined subgenera within the complex are each well-supported as monophyletic. Most striking was the discovery that a small set of morphologically and ecologically heterogeneous species formed a clade, here called subgenus Nothonepha. This unexpected result was corroborated by the discovery of deep pits in the lateral body wall (in the mesepisternum) of all Nothonepha, a trait unique within Bembidion. These pits are filled with a waxy substance in ethanol-preserved specimens. In one newly discovered species (Bembidion tetrapholeon sp. n., described here), these pits are so deep that their projections into the body cavity from the two sides touch each other internally. These structures in Bembidion (Nothonepha) are compared to very similar mesepisternal pits which have convergently evolved in two other groups of carabid beetles. The function of these thoracic pits is unknown. Most members of subgenus Nothonepha have in addition similar but smaller pits in the abdomen. A revised classification is proposed for the Antiperyphanes Complex.

Highlights

Ground beetles of the genus Bembidion are distributed throughout the temperate regions of the world (Maddison 2012)
Many species resemble northern-hemisphere subgenera scattered throughout the two major clades of Bembidion, all known species in South America are members of only three groups within the Bembidion Series: the subgenera Notaphus and Nothocys, as well as the Antiperyphanes Complex (Maddison 2012)
Eight subgenera are considered to belong to the complex (Maddison 2012; Maddison et al 2013): Antiperyphanes Jeannel, Antiperyphus Jeannel, Chilioperyphus Jeannel, Plocamoperyphus Jeannel, Nothonepha Jeannel, Pacmophena Jeannel, Notholopha Jeannel, and Ecuadion Moret and Toledano, with two subgenera suspected of belonging (Notoperyphus Bonniard de Saludo (1969), Pseudotrepanes Jeannel (1962)). Members of this complex are moderately diverse in form, and are typically shades of brown, orange, and yellow, a few species have metallic colors (Figs 1–3) They are abundant along edges of bodies of water in south temperate regions, and at higher elevations from Patagonia north into Central America

Summary

Introduction

Ground beetles of the genus Bembidion are distributed throughout the temperate regions of the world (Maddison 2012). Eight subgenera are considered to belong to the complex (Maddison 2012; Maddison et al 2013): Antiperyphanes Jeannel, Antiperyphus Jeannel, Chilioperyphus Jeannel, Plocamoperyphus Jeannel, Nothonepha Jeannel, Pacmophena Jeannel, Notholopha Jeannel, and Ecuadion Moret and Toledano, with two subgenera suspected of belonging (Notoperyphus Bonniard de Saludo (1969), Pseudotrepanes Jeannel (1962)) Members of this complex are moderately diverse in form, and are typically shades of brown, orange, and yellow, a few species have metallic colors (Figs 1–3) They are abundant along edges of bodies of water (rivers, creeks, ponds, lakes, snowfields, and ocean; Figs 4A,B) in south temperate regions (especially Argentina, Chile, Peru, and Bolivia), and at higher elevations from Patagonia north into Central America. In the mountains of Ecuador, Peru, and nearby areas, one group (subgenus Ecuadion) has radiated into alpine grasslands (Fig. 4C), cloud forest leaf litter (Fig. 4D), clay cliffs, and other habitats distant from open water

Methods

Results

Conclusion