Séguy, 1935 : 153 Séguy, 1935 : 153 A new species of Acantothereva Séguy, 1935, from Tunisia (Diptera: Therevidae: Therevinae): taxonomic consequences and phylogenetic implications Holston, Kevin C. Zootaxa 2009 2155 28 36 MG9 359423 Seguy, 1935 Seguy 1935 [151,480,1296,1323] Insecta Therevidae Acantothereva Animalia Diptera 3 31 Arthropoda genus     Acantothereva  Séguy, 1935: 153. Typespecies:  Acantothereva rungsi  Séguy, 1935: 153, by original designation.  Acanthothereva Lyneborg, 1968: 298. Unjustified emendation. Noted as a “lapsus calami” by Lyneborg (1968: 298).   Diagnosis. Male eyes separated by more than 5Xwidth of anterior ocellus, upper and lower ommatidia of equal size. Posterior margin of head in dorsal view strongly convex; ocellar tubercle slightly raised (the condition observed in most therevine genera) to dilated with ocelli widely separated with posterior ocelli directed posteriorly, upper frons and vertex sunken to distended with respect to eye margin. Antennal insertion low; parafacial setae present; female frons with uniform tomentum. Wing membrane opaque white with dark maculation extensive without forming bands or large contiguous dark regions. Femoral cuticle varying from yellow or yellowish brown to black; tibial apices slightly dilated; subapical macrosetae of tibiae long: protarsus and pulvilli small. Distiphallus hook-like (extending dorsad from base and decurved to apex), laterally compressed with apex broadly rounded to truncate in lateral view. Small species: 6–7 mm.   Comments: Extending on the original description of  Acantotherevaas a monotypic genus by Séguy (1935), Lyneborg (1968)listed nine “apomorphies” [=synapomorphies], noting that several of these characters are less pronounced in  A. punctipennisthan  A. rungsi. These characters were 1) the broad separation of the male compound eyes, 2) the “elevated” upper frons and vertex with a poorly defined ocellar tubercle, 3) widely separated ocelli with the two posterior ocelli directed posteriorly, 4) a low antennal insertion, 5) maculated wings, 6) the “gradually” dilated tibial apex, 5) tibiae with long subapical macrosetae, 7) small protarsus and pulvilli, 8) a “stout phallus, 9) and the comparatively short dorsal, ventral and ejaculatory apodemes.” These external characters are useful for distinguishing  Acantotherevawithin the context of the western Palaearctic stiletto fly fauna, but only the morphology of the distiphallus provides an unambiguous diagnostic feature. Broad separation of the male compound eyes is unusual in Therevidaebut has been noted for therevine genera readily distinguished from  Acantothereva(e.g.,  Chrysanthemyia) as well as  Neotherevella, which is similar in external morphology to  Acantothereva( Lyneborg 1978, 1983a). An elevated frons and expanded ocellar tubercle is characteristic of the typespecies,  A. rungsi, and less pronounced in  A. punctipennis; the ocellar tubercle of the Tunisian species is unmodified and situated below the dorsal eye margin; and the ocelli are directed posteriorly only in  A. rungsi. A low antennal insertion, maculated wings, and dilated tibia apex are present in the Tunisian species, but these characters have been observed across a broad sample of therevine genera ( Lyneborg 1976, 1983b, Gaimari & Irwin 2000, Hauser & Irwin 2004). Although the dorsal, ventral and ejaculatory apodemes in  Neotherevellaare similar to those in  Acantothereva(c.f., Lyneborg 1968: Figs 11–12; Lyneborg 1976: Figs 236, 327), the laterally compressed distiphallus with a broadly rounded to truncate apex is unique to  Acantothereva.