Pison excisum Pulawski, 2018

Pulawski, Wojciech J., 2018, A Revision of the Wasp Genus Pison Jurine, 1808 of Australia and New Zealand, New Guinea, and the Pacific Islands (Hymenoptera: Crabronidae), Proceedings of the California Academy of Sciences 65, pp. 1-584 : 180-182

Pison excisum Pulawski , species nova

Figures 388 -393.

NAME DERIVATION.– Excisum, the perfect passive participle (gender: neuter) of the Latin verb excidere, to cut out; with reference to the deeply cut out apical margin of male sternum VIII.

RECOGNITION.– Only the male of this species is known. It is characterized by an all black body, the presence of three submarginal cells, the second recurrent vein joining the third submarginal cell near its base, and setae appressed on tergum I. It differs from all other Pison in having a unique sternum VIII, which is unusually deeply emarginate, with the margins of the emargination converging toward the apex, hence the emargination is the broadest near the middle of its length (Fig. 390). Sternum VIII is also unusually deeply emarginate in P. perplexum and in P. petraeum , from which P. excisum differs by a number of characters. In P. excisum , the dorsal length of flagellomere I is 2.1 × apical width (3.3 × apical width in P. perplexum ), the flagellomeres have no tyloids (tyloids present on flagellomeres II-V in perplexum ), the ocellocular distance is equal to 1.0 × hindocellar diameter and is smaller than the distance between the hindocelli (in P. perplexum , it is equal to 1.6 × hindocellar diameter and is larger than the distance between the hindocelli), the sternal punctures, particularly on the preapical sterna, are conspicuous, whereas they are moderately large in P. perplexum , the apical margin of sternum VII is conspicuously concave (practically straight in P. perplexum ), and sternum VIII at apex is not bent ventrally (conspicuously bent ventrally in P. perplexum ). Unlike P. petraeum , the ocellocular distance of P. excisum is 1.0 × midocellar diameter (rather than 1.4-1.6 ×) and is smaller than the distance between the hindocelli (rather than larger), the setae of the lower gena are sinuous (rather than straight of with curved apex), the propodeum has no longitudinal carina between the spiracle and the gastral insertion (carina present in P. petraeum ), and the margins of the emargination on sternum VIII are converging toward the apex (rather than diverging).

DESCRIPTION.– Frons dull, finely punctate, punctures less than one diameter apart; interspaces dull, microsculptured. Labrum not emarginate. Anteromedian pronotal pit transversely elongate, about as long as midocellar diameter. Scutum not foveate along flange, without short longitudinal

Body all black.

♀.– Unknown.

♂.– Upper interocular distance equal to 0.84 × lower interocular distance; ocellocular distance equal to 1.0 × hindocellar diameter, distance between hindocelli equal to 1.3 × hindocellar diameter; eye height equal to 0.90 × distance between eye notches. Free margin of clypeal lamella acutely angulate ( Fig. 388 ). Dorsal length of flagellomere I 2.1 × apical width, of flagellomere X 1.2 × apical width. Sternum VIII conspicuously, deeply emarginate, with side of emargination concave, hence emargination broadest in middle (Fig. 390). Genitalia: Figs. 391, 392. Length 11.3 mm; head width 2.8 mm.

GEOGRAPHIC DISTRIBUTION (Fig. 393).– Known from one locality in Western Australia.

RECORDS.– HOLOTYPE: ♂, AUSTRALIA: Western Australia: Juna Downs Station at 22°51.30ʹS 118°40.14ʹE, 3-8 Jan 2006, CVA [= Conservation FIGURE 393. Collecting locality of Pison excisum Pulaw- Volunteers Australia] ( AMS). ski, sp. nov.

Figures

FIGURES. 388-389. Pison excisum Pulawski, sp. nov., male. (Fig. 388) Clypeus; (389) Sternum II in ventral view; (390) Sternum VIII (ventral surface); (391) Genitalia in dorsal view; (392) Genitalia in lateral view.