Wallaceaphytis kikiae Ayshford and Polaszek, 2013

Polaszek, Andrew, Ayshford, Thomas, Yahya, Bakhtiar Effendi & Fusu, Lucian, 2013, Wallaceaphytis: an unusual new genus of parasitoid wasp (Hymenoptera: Aphelinidae) from Borneo, Journal of Natural History (J. Nat. Hist.) 48 (19 - 20), pp. 1111-1123 : 1116-1119

Type species Wallaceaphytis kikiae Ayshford and Polaszek sp. nov.

( Figures 3–11 )

Description/generic diagnosis

Morphology. Antenna with three segments ( Figure 5 ), scape, pedicel and a single flagellar segment. Anellus present, narrower on its internal side. Scape narrow, length 5× maximum width. Maximum width of pedicel 1.6× maximum width of scape. Flagellum length 2.9× maximum width, and 1.4× scape. Head strongly transverse ( Figures 4 and 8 ) 2.9× as wide as long in dorsal view (unmounted specimen Figure 8 ); 1.3× as wide as maximum width of mesosoma in dorsal view ( Figure 8 ). Mandible very small, with two teeth and a small truncation; mandibular glands elongate, parallel-sided. Maxillary palp two-segmented, labial palp one-segmented. Lateral ocellus separated from eye margin by slightly more than the maximum width of ocellus. Pronotum centrally membranous, each side with a robust seta at the lateral edge, a fine seta adjacent to it, and two fine setae further towards the centre. Mid-lobe of mesoscutum with two setae laterally. Each side lobe of mesoscutum with two setae; tegula with a robust seta; axilla without setae; scutellum transverse, with two pairs of setae. Propodeum elongate centrally, projecting posteriorly, with a central process, and without crenulae ( Figure 3 ). Propodeal spiracle without anterior groove. Mesofurca of typical Aphytini form ( Figure 7 ; see Heraty et al. 1997). All tarsi four-segmented. Fore wing 3.8× as long as maximum width of disc (excluding marginal fringe); submarginal vein with a single seta; stigmal vein well-developed ( Figure 6 ). Fore wing without setae below marginal vein, remainder of wing very sparsely setose. Anterior gastral sterna without projections (see Woolley 1988, p.469). T1–T6 of gaster each with a pair of setae, T7 (syntergum) with two pairs of setae, and in the form of a single sclerite, undivided and without epiproct.

Comments

Wallaceaphytis presents a combination of characters that is so far unique among the family Aphelinidae . Within the family, Wallaceaphytis is clearly a member of the subfamily Aphelininae , as shown above based on DNA sequence data, and as follows based on morphological data. The reduced number of antennal segments (three in the present case), elongate and parallel-sided mandibular glands, medially membranous pronotum, propodeal spiracles without anterior grooves, sterna without anterior apodemes, Aphytis -like mesofurca and presence of a syntergum, exclude all other subfamilies. Wallaceaphytis superficially resembles Ablerus , especially the unusual fore wing, but can be easily excluded from that genus and from the subfamily Azotinae (family Azotidae ) by the above combination of characters. Eretmocerus has been included in Aphelininae by some authors, and also has four-segmented tarsi, while the antennae are five-segmented in females and three-segmented in males. However, in virtually all other respects the two genera are very distinct, and Eretmocerus appears to be only distantly related to Aphelininae . Marlatiella is the only known genus that also has three-segmented female antennae, but has five-segmented tarsi and very different wing characters.

Molecular DNA analysis supports the status of Wallaceaphytis as a distinct genus with unresolved affiliations or allied more closely with Centrodora , but this relationship is weakly supported. Despite the Bayesian analysis placing Wallaceaphytis in a polytomy with Marietta , Aphytis and Aphelinus , morphology, and the maximum likelihood analysis, suggest a closer relationship with Centrodora . In the key to genera of Aphelininae by Kim and Heraty (2012) Wallaceaphytis keys immediately with Eretmocerus because of the four-segmented tarsi, but is easily separated from this genus by the three-segmented female antenna, and long marginal vein. Although Wallaceaphytis is superficially similar to Ablerus , the molecular analysis (as with the comparison of morphology discussed above) clearly shows that this genus belongs to Aphelininae and not to Azotinae .

Figures

Figure 3. Wallaceaphytis kikiae holotype female; mesosoma and metasoma.

Figure 4. Wallaceaphytis kikiae holotype female; head: dorsal (above), ventral (below).

Figure 5. Wallaceaphytis kikiae holotype female; antennae.

Figure 6. Wallaceaphytis kikiae holotype female; fore wing.

Figure 7. Wallaceaphytis kikiae holotype female; mesofurca.

Figure 8. Wallaceaphytis kikiae holotype female; habitus.

Figure 9. Wallaceaphytis kikiae holotype female; habitus.

Figure 10. Wallaceaphytis kikiae holotype female; habitus.

Figure 11. Wallaceaphytis kikiae holotype female; habitus.