Mythenteles Hall & Evenhuis

Evenhuis, Neal L., 2003, World revision of the microbombyliid genus Mythenteles Hall & Evenhuis (Diptera: Mythicomyiidae), Zootaxa 346, pp. 1-28 : 2-4

Genus Mythenteles Hall & Evenhuis

Mythicomyia (Mythenteles) Hall & Evenhuis, 1986: 332 . Type species: Mythicomyia mutabilis Melander, 1961 [= Empidideicus propleuralis Melander, 1946 ], by original designation. Empidideicus (Cladella) Hull, 1973: 273 . Evenhuis, 1983: 398. Nomen nudum. Cladella Hall & Evenhuis, 1987: 618 . Type species: Empidideicus propleuralis Melander, 1946 , by original designation.

Mythenteles Hall & Evenhuis. Evenhuis, 1991: 53 ; Greathead & Evenhuis, 2001: 127; Evenhuis, 2002b: 36.

Evenhuis (1991: 53) dealt with the generic synonymy of Mythenteles and raised it from subgeneric to generic status. Mythenteles was originally distinguished from Mythicomyia Coquillett s. str. by the presence of the basal portion of vein M separating cells bm and br, the reduced anal lobe in the wing, and the female genitalia with varying elaborate shapes of the apical valve of the sperm pump. At the time of the original description of Mythenteles , males were not known. The reason for this was that all specimens of Mythenteles examined by Hall & Evenhuis (1986) were dichoptic and were assumed to be female (all these specimens were thought at that time to be members of the genus Mythicomyia , which has holoptic males and dichoptic females). Subsequent collection by me of a mating pair of specimens of Mythenteles helped solve the mystery of the supposed absence of males by forcing an examination of the genitalia of the specimens collected to ensure they were of different sexes. Males and females were then discovered to both be dichoptic.

Further examination of specimens and comparison with other genera on a worldwide basis showed that species in this genus had characters more similar to Empidideicus Becker than Mythicomyia (cf. Figs. 2–5 ; antennal first flagellomere is short, the anal lobe of the wing is not well developed, and the shape and structure of the vaginal furca are similar to those exhibited in Empidideicus ). These characters led Evenhuis (1991) to raise Mythenteles to generic status. Subsequent to the work of Evenhuis (1991), Greathead and Evenhuis (2001) reviewed the status of the subfamilies comprising Mythicomyiidae and placed Mythenteles in the Mythicomyiinae . Evenhuis (2002a) provided a key to the genera of Mythicomyiinae . The subfamily is currently defined as containing those genera of Mythicomyiidae with vein R4+5 ending in the costa at a level at or slightly beyond the end of vein M2 and which possess a small triangular marginal cell formed by veins Rs (radial sector), R1, and R2+3 1.

Previous to Evenhuis (2002a), 5 species were known in Mythenteles , all from the New World. Comparison of the male and female genitalia as well as differences observed in wing venation and antennal characters has shown that species previously comprising Mythenteles actually belonged in 2 separate genera. Mythenteles is thus restricted to those species with an apically placed antennal style on the second flagellomere; a lack of conspicuous interhumeral markings on the mesonotum (although humeral markings may be present), a prominent posteriorly oriented epandrial process in the male genitalia (termed “pseudosurstylus” here), and a U­shaped vaginal furca and spherically to subconically shaped spermathecal reservoirs in the female genitalia. The remainder of the species previously placed in Mythenteles were transferred to the genus Pieza Evenhuis (Evenhuis, 2002a) .

After re­examination in this study of specimens previously identified as either mutabilis or propleuralis , it is concluded that the synonymy of mutabilis with propleuralis be maintained; however, the majority of the Nearctic specimens examined belong to a new species, M. silus , described below. With the addition of 10 species to the genus (8 newly described) and the transfer of 4 of the 5 originally included species to Pieza , the total number of species in Mythenteles is now 13 (12 extant, 1 fossil).

The disjunct distribution of the genus (western North America, Greece, Cyprus, Spain, China, Bangladesh, India, Israel, and Palestine; see Fig. 1 ) is presumably relict. Further concentrated collecting in and between these localities should turn up more representatives of this genus. One fossil species ( M. baltica Evenhuis ) was described from Baltic amber ( Evenhuis, 2002c) giving evidence of a lineage at least as old as the Eocene/Oligocene.

Specimens are relatively uncommon in collections. Aside from specimens of the 2 species from western North America, the genus is only known from a total of 78 specimens worldwide.

1. Paraconsors Hall & Evenhuis was listed under Mythicomyiinae in Evenhuis (2002b), but this is an error. Paraconsors should be placed Empidideicinae since it lacks a vein R2+3.

Figures

FIGURE 1. World map indicating known distribution of Mythenteles.

FIGURES 2 – 5. Comparisons of Mythicomyia and Mythenteles. 2 – 3. Antennae. 2. Mythicomyia pusillima Melander; 3. Mythenteles propleuralis (Melander). 4 – 5. Wings. 4. Mythicomyia brevis Hall & Evenhuis; 5. Mythenteles propleuralis (Melander).