| Abstract: | The Hister servus group contains ten species and two species complexes. Although the group’s diversity is centred in Mexico and Central America, one lineage, comprising H. indistinctus Say, H. defectus LeConte and H. fungicola Schaeffer, has probably diversified entirely in the south-eastern U.S. The servus group also contains the following species: H. servus Erichson , H. nodatus lewis , H. doyeni sp.n., H. lagoi sp.n., H. bullatus lewis , H. coronatus Marseul and H. diadema Marseul and two diverse species complexes, dubbed the comes complex and the montivagus complex. These two complexes require additional sampling and study before species within them can be recognized. They are, however, closely related to each other and appear to be paraphyletic with respect to a clade comprising H. bullatus, H. coronatus and H. diadema. A prior hypothesis that the servus group includes H. sallei, H. matador sp.n. and the species of Hister (Spilodiscus) is not well supported. Several sister groups within the servus group show geographical disjunction between seasonal tropical habitats of western North America and wetter montane habitats of the eastern parts of the continent along the Gulf and Caribbean coasts. |
