A Revision of Stizoides Guérin-Méneville, 1844: Taxonomy, Phylogenetic Relationships, Biogeography, and Evolution (Hymenoptera: Apoidea, “Sphecidae”)

Abstract

The genus Stizoides Guerin-Meneville is revised for the first time, and 31 species and two subspecies are recognized. The revision includes identification keys, diagnoses, descriptions, summaries of known life histories, illustrations of important characters, and distribution maps. Seven new species are described: aryan (India), eogaster (India), fulani (Cameroon), rubifunebris (Mali, Nigeria, Sudan), sahel (Mauritania to Chad), sokoto (Nigeria), and zulu (southern Africa). One new subspecies of fenestratus (F. Smith) from northern Africa, boreus, is described. Lectotypes are designated for blandinus (F. Smith), citrinus (Klug), conscriptus (Nurse), fulvipes Eversmann, melleus (F. Smith), tuberculiventris (Turner), and unifasciatus (Radoszkowski); the latter, previously synonymyzed with tridentatus, is recognized as a valid subspecies of tridentatus. Six new synonyms are established: Stizoides poecilopterus (Handlirsch, 1892) and egregius (Gussakovskij, 1928) = assimilis (Fabricius, 1787), ctenopus (G. Arnold, 1929) = tuberculiventris (Turner, 1912), klugii numida (Schulz, 1905) = klugii (F. Smith, 1856), and Stizus melanoxanthus (F. Smith, 1856) and melleus (F. Smith, 1856) = Stizoides citrinus (Klug, 1845). A phylogenetic hypothesis is proposed for the species of Stizoides. Fifty-six characters are analyzed and their phylogenetic significance is evaluated, including numerous previously unnoticed characters. Two monophyletic species groups are recognized: the assimilis and the tridentatus groups. Based on the phylogenetic analysis, the historical biogeography of Stizoides is reconstructed. The species of Stizoides are cleptoparasites on Orthoptera-preying sphecid wasps. The original host of the stem species of Stizoides was putatively an immediately related Stizus species, and thus Stizoides can be considered agastoparasite. EMERY'S rule is reevaluated from a phylogenetical standpoint. The evolution of cleptoparasitism in Stizoides is discussed. A sympatric and an allopatric speciation model are compared. The temporal appearence of autapomorphies in relation to the completion of the speciation process is discussed.