Pison mariannense Yasumatsu

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 : 541-543

Pison mariannense Yasumatsu

Figures 1314-1319.

Pison mariannense Yasumatsu, 1953:141 , ♀, ♂. Holotype: ♂, Mariana Islands: Island of Rota: Tetêcho-Tatâcho-Soñgsoñg (ELKU), examined. – Yasumatsu, 1953: 134 (in list of Pison of Pacific islands ); Tsuneki, 1968b:22 (Marianas, as marianense); R. Bohart and Menke, 1976:336 (in checklist of world Sphecidae ).

RECOGNITION.– Pison mariannense is unique among its Pacific Islands congeners in having an unusual wing venation: the apex of the marginal cell and that of the third submarginal cell are almost equidistant from the wing apex (Fig. 1318) rather than the apex of the marginal cell being markedly closer to the wing apex than that of the third submarginal cell. Subsidiary recognition features are: setae of lower gena slightly sinuous, up to about 1.5 × as long as midocellar diameter, appressed on tergum I; propodeum without carina separating side from dorsum and posterior surface.

DESCRIPTION.– Frons dull, conspicuously microsculptured, minutely punctate, punctures several diameters apart. Occipital carina joining hypostomal carina. Gena narrow in dorsal view. Labrum not emarginate. Anteromedian pronotal pit transversely elongate, about as long as 1.5 × midocellar diameter. Scutum not foveate along flange, with short longitudinal ridges adjacent to posterior margin; scutal punctures well defined, many diameters apart at center, in male about one diameter apart anterolaterally and posterolaterally; interspaces aciculate. Tegula not enlarged. Mesopleural punctures well defined, 1-2 diameters apart at center; interspaces aciculate. Postspiracular carina present, about as long as midocellar diameter. Metapleural sulcus costulate between dorsal and ventral metapleural pits. Propodeum without longitudinal carina separating side from dorsum and posterior surface; dorsum obliquely ridged (in female ridges reduced mesally), punctate between ridges (Figs. 1316, 1317); side ridged, ridges fine anteriorly, coarser posteriorly (invisible from certain angles), integument punctate between ridges; posterior surface conspicuously, transversely ridged, punctate between ridges, ridges extending onto lateral surface. Wing venation unusual: apex of marginal cell and that of third submarginal cell almost equidistant from wing apex (Fig. 1318). Posteroventral forefemoral surface impunctate in female, in male with well-defined punctures that average one diameter apart. Punctures of tergum I minute, several diameters apart anterior to apical depression. Sternum II with minute punctures that are several to many diameters apart (except close to each other near lateral margin in male).

Setae silvery, erect on upper frons (and about 1.5 × as long as midocellar diameter in female, slightly longer than midocellar diameter in male), appressed on most of postocellar area, erect on scutum (here about as long as midocellar diameter), appressed on tergum I; on lower gena slightly sinuous, up to about 2.0 × midocellar diameters in female, about 1.5 in male; not concealing integument on clypeus. Apical depressions of terga without silvery, setal fasciae in female, with ill-defined silvery, setal fasciae in male.

Body all black

♀.– Upper interocular distance equal to 0.62 × lower interocular distance; ocellocular distance equal to 0.4 × hindocellar diameter, distance between hindocelli equal to 0.8 × hindocellar diameter; eye height equal to 0.94 × distance between eye notches. Free margin of clypeal lamella roundly subtruncate (Fig. 1314). Dorsal length of flagellomere I 2.2 × apical width, of flagellomere IX 1.3 × apical width. Mandible: trimmal carina with small incision at about two thirds of length. Length 8.7 mm; head width 2.4 mm.

♂.– Upper interocular distance equal to 0.68 × lower interocular distance; ocellocular distance equal to 0.9 × hindocellar diameter, distance between hindocelli equal to 0.9 × hindocellar diameter; eye height equal to 1.00 × distance between eye notches. Free margin of clypeal lamella obtusely angulate (Fig. 1315). Dorsal length of flagellomere I 1.8 × apical width, of flagellomere X 1.1 × apical width. Sternum VIII with apical margin rounded. Length 7.0 mm; head width 2.0 mm.

GEOGRAPHIC DISTRIBUTION (Fig. 1319).– Known only from the islands of Rota and Saipan in the Mariana archipelago.

RECORDS.– MARIANA ISLANDS: Rota Island : Tetêto-Tatâcho-Soñgsoñg (1 ♂, ELKU, holotype of Pison mariannense ) . Saipan: Fanagam (1 ♀, ELKU, allotype of Pison mariannense ) .