Taxonomic revision of imitating carpenter ants, Camponotus subgenus Myrmopytia (Hymenoptera, Formicidae) of Madagascar, using morphometry and qualitative traits.

Nicole Rasoamanana,Brian L Fisher,Sándor Csősz

doi:10.3897/zookeys.681.13187

Abstract

The ant genus Camponotus (Mayr, 1861) is one of the most abundant and species rich ant genera in the Malagasy zoogeographical region. Although this group is commonly encountered, its taxonomy is far from complete. Here, we clarify the taxonomy of the Malagasy-endemic Camponotus subgenus Myrmopytia (Emery, 1920). Species delimitation was based on traditional morphological characters and multivariate morphometric analyses, including exploratory Nest Centroid clustering and confirmatory cross-validated Linear Discriminant Analysis. Four species are recognized: Camponotus imitator (Forel, 1891), Camponotus jodina sp. n., Camponotus karaha sp. n., and Camponotus longicollis sp. n. All four species appear to mimic co-occurring Aphaenogaster species. A diagnosis of the subgenus Myrmopytia, species descriptions, an identification key based on minor and major subcastes of workers, and the known geographical distribution of each species are provided.

Highlights

Malagasy Camponotus species are known to mimic other ant species or genera, such as Tetraponera, Catalaucus and Aphaenogaster, highlighting the incredible potential for morphological adaptation in Camponotus species (Forel 1886, Ward 2009, BLF, pers. obs.)
We have attempted to overcome the problem of morphological variation in the Malagasy-endemic Camponotus subgenus Myrmopytia (Emery, 1920) by combining traditional morphology with a numeric morphology-based approach
In cluster 2 two samples remarkably differ in morphology from the other specimens in the cluster

Summary

Introduction

Malagasy Camponotus species are known to mimic other ant species or genera, such as Tetraponera, Catalaucus and Aphaenogaster, highlighting the incredible potential for morphological adaptation in Camponotus species (Forel 1886, Ward 2009, BLF, pers. obs.). The third complication is that the existing subgenus classification of Camponotus is an amalgamation of past taxonomic works that have tried to “fix” the problem of taxa delimitation by adding new names rather than by completely revising the global classification (Bolton 1995, Clouse et al 2015, Ward et al 2016). We have attempted to overcome the problem of morphological variation in the Malagasy-endemic Camponotus subgenus Myrmopytia (Emery, 1920) by combining traditional morphology (i.e. evaluation of qualitative traits) with a numeric morphology-based approach. This work does not address the issue of the unnatural subgeneric classification for the genus which is better addressed with molecular phylogenetic methods and global sampling Instead, for this revision, we retain the historic subgenus Myrmopytia, for Camponotus imitator (Forel, 1891), and include for the convenience of this revision, species with morphologically similar workers.

Materials and methods

Methods

Results and discussion