Elissoma White
Creators: name: Winterton, Shaun L.
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Stratiomyidae
Elissoma

description: Elissoma White
Elissoma White, 1916: 86 — Hardy, 1920: 49 [key, checklist], 1933: 409 [key, revision]; Woodley, 1989: 314 [catalogue], 2001: 166 [catalogue]. Type species: Elissoma lauta White, 1916, by monotypy.
Pycnothorax Kertész, 1923: 124 — Woodley, 1989: 315 [catalogue], 2001: 172 [catalogue]. Type species: Pycnothorax australis Kertész, 1923: 125, by original designation. Syn. n.
Diagnosis. One pair of minute to moderately-sized scutellar spines, shorter than scutellum length; notopleural spine absent; wing vein M 3 present or absent; M 4 arising on discal cell, cross-vein r–m present; wing straight, not bent over abdomen; face flat to broadly rounded, without nose-like process; male eyes contiguous medially below ocellar tubercle; eye not pilose; postocular ridge broadly carinate in female, male narrow to broadly carinate; antenna greatly elongate, scape much shorter than flagellum; flagellum cylindrical, circular sensory pits on flagellomeres I–III, flagellomeres IV–V very short and of similar length; flagellomere VIII longer than all other flagellomeres combined, covered with deeply plumose microtrichia or more sparse larger setae, sometimes white apically; abdomen narrowed basally, ovoid to strongly petiolate, frequently strongly sexually dimorphic.
Included species. Elissoma australis (Kertész, 1923) comb. n.; E. brunnea Hardy, 1933; E. gilva sp. n.; E. danielsi sp. n.; E. hauseri sp. n.; E. ichneumonoides sp. n.; E. hespera sp. n.; E. lauta White, 1916; E. minuta sp. n. and E. scapula sp. n.
Comments. Hardy (1933) noted that Elissoma and Pycnothorax were very similar and belonged to the same group of genera, even suggesting that they may be congeneric. He discussed that the generic distinctions amongst these genera are poor and went on to state that: “…variations of this nature cannot be accepted as of generic importance and it becomes very evident as more species accumulate, that the genera will need to be erected on better grounds than has been done in the past.” (Hardy 1933: p. 410).
White (1916) did not list the gender of Elissoma in his original description and the etymology of the genus is unclear, although the species epithet of the type species is feminine. In contrast to all previous authors, Woodley (1989) used the neutral form of the combinations of E. lautum and E. brunneum, and then the original feminine form in Woodley (2001); the feminine form for Elissoma is likewise used here. Most Elissoma species are found in the eastern Australian states of New South Wales, Victoria and Queensland, with the bulk of species found in coastal Queensland. Two species are known from Western Australia. Elissoma is very similar to Ampsalis but is differentiated by a rounded or flat face, lacking the ‘nose’-like process of the latter. The scutellar spines are general very small to minute; when present in other genera they are larger. The only other clitellariine genera in the Oriental and Australian regions with scutellar spines (and lacking notopleural spines) are Campeprosopa and Ampsalis. Antennal length is extremely variable in this genus (ranging from 1.5 mm in E. minuta sp. n. to 8.5 mm in E. ichneumonoides sp. n.), but proportions of flagellomeres remain relatively constant; these proportions are typically not found in other Clitellariinae genera aside from Ampsalis and some Lagenosoma.
Key to Elissoma species
1. Wing vein M 3 absent (Fig. 21A)........................................................................ 2.
- Wing vein M 3 present (Fig. 21B–D)..................................................................... 3.
2. Body predominantly orange with black markings (Fig. 32C); antennae yellow basally; foretarsi white; wing with smoky infuscation medially (Figs 11C, D; 21A) (Queensland)............................................. E. brunnea Hardy.
- Body predominantly black with dark yellow line dorsally along anepisternum and laterally on abdomen (Figs 13E; 32E); antennae entirely black; foretarsi black; wing hyaline (Fig. 13F) (Western Australia)....................... E. minuta sp. n.
3. Wing largely uniform dark infuscate; scutum tri-coloured, anteriorly dark yellow (orange in living specimen), black in middle section and white (pink in living specimen) posteriorly, concolourous with scutellum (Figs 2; 13C, D) (Victoria, New South Wales)................................................................................. E. lauta White.
- Wing hyaline; scutum and scutellum otherwise coloured..................................................... 4.
4. Antennae completely dark; setae present along flagellomeres V–VIII; male postocular ridge raised and angular (Figs 25J; 26A, B)................................................................................................ 5.
- Antennae dark with distal flagellomeres white (Fig. 25E–I) (completely black in E. hauseri sp. n. (Fig. 27K); setae absent on flagellum; male postocular ridge not raised and angular...................................................... 6.
5. Scutum yellow with dark brown markings (Fig. 12E–H); abdomen yellow with brown markings (Fig. 32G); scutellar spines minute (Fig. 28G) (Queensland)............................................................ E. hespera sp. n.
- Scutum orange with black punctate markings indicating setal bases, pitch black anteriorly and anterolaterally (Fig. 13G, H); scutellar spines well developed (Fig. 29A) (Western Australia).................................... E. scapula sp. n.
6. Pleuron predominantly black, narrowly yellow around base of wing (Fig. 13A); antennae very long (ca. 5x head length) (Fig. 25I); scutellar spines at least half the length of scutellum (Fig. 28I) (Queensland).............. E. ichneumonoides sp. n.
- Pleuron predominantly pale (orange, yellow or white) with portions of some sclerites black; antenna length at most 4x head length; scutellar spines less than half the length of scutellum................................................... 7.
7. Scutellum orange-brown with cream-white margin (Fig. 28E); anepisternum with dark brow spot dorsally; hind tibia with dark brown band (Fig. 12A–D) (Queensland)...................................................... E. danielsi sp. n.
- Scutellum otherwise coloured; anepisternum black anteriorly, white to yellowish green posteriorly (sometimes also dorsally); hind tibia entirely yellow or brownish black................................................................ 8.
8. Scutellum orange (Fig. 28F); hind tibia dark yellow (Fig.11E, F) (New South Wales).................... E. gilva sp. n.
- Scutellum green to white (depending on preservation) (Fig. 28C, H); hind tibia brownish black....................... 9.
9. Flagellum white distally (Fig. 25E); scutellum uniform green to white (Fig. 28C); postpronotum and katatergite black, anepisternum brownish black anteriorly, green to white posteriorly; hind tarsi white apically (Fig. 11A, B) (Queensland).......................................................................................... E. australis (Kertész).
- Flagellum entirely black (Figs 4, 27K); scutellum with brown central marking contiguous with dark stripe on scutum (Fig. 28H); postpronotum and katatergite green to white, anepisternum brownish black anteriorly, green to white dorsally and posteriorly; hind tarsi entirely black (Fig. 11G, H) (Queensland, Victoria)............................... E. hauseri sp. n.
description: Published as part of Winterton, Shaun L., 2023, Wasp-mimicking soldier flies of the Australian Region: revision of Ampsalis Walker, Elissoma White and Lagenosoma Brauer (Stratiomyidae: Clitellariinae), pp. 1-63 in Zootaxa 5246 (1) on pages 17-19, DOI: 10.11646/zootaxa.5246.1.1, http://zenodo.org/record/7673215