Pison oakleyi Krombein

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 : 549-551

Pison oakleyi Krombein

Figures 1338-1344.

As Pison sp. : Fullaway, 1913:283 ( Guam) and Swezey, 1942:185 ( Guam), corrected to Pison oakleyi by Krombein, 1949b:406.

Pison oakleyi Krombein, 1949b:406 , ♂, ♀. Holotype: ♂, Guam: Point Ritidian (USNM), paratypes examined. – Krombein, 1949b:385 (in key to Sphecidae of Micronesia), 1950b:134 and 139 (illustrations of head, sternum III, and genitalia); Yasumatsu, 1953:134 (in list of Pison of Pacific islands), 144 (bibliographic references; Mariana Islands); R. Bohart and Menke, 1976:336 (in checklist of world Sphecidae ); Terayama and Nambu, 2009:2, 23 (in key to Trypoxylini of Japan).

Pison oakleyi rotaense Tsuneki, 1968b:22 , ♀, ♂. Holotype: ♂, Mariana Islands: Rota Island (Bishop Mus.). – R. Bohart and Menke, 1976:336 (in checklist of world Sphecidae ).

Pison oakleyi boninense Tsuneki, 1973:19 , ♀. Holotype: Japan: Bonin Islands: Island of Chichidzima (K. Haneda coll.). – Haneda, 1973:30 ( Japan: Bonin Islands: Chichijimas Islands); R. Bohart and Menke, 1976:336 (in checklist of world Sphecidae ); Tsuneki, 1984a:11 (known from Ogasawara = Bonin Islands); Takahashi, 2010:19 ( Japan: in list of Hymenoptera of Ogasawara = Bonin islands).

RECOGNITION.– Pison oakleyi resembles P. westwoodii in most characters. Like that species, it has a black body, three submarginal cells, the second recurrent vein contiguous with the second intersubmarginal vein or nearly so, the setae shorter than midocellar width on the lower gena and appressed on tergum I, punctures more than one diameter apart on the mesopleuron, and a narrow ocellocular distance (equal to 0.2 × midocellar diameter in the female and to 0.3 × in the male), the apex of the marginal cell markedly closer to the wing apex than that of submarginal cell III, and tergum I not microareolate between the punctures. It differs from P. westwoodii in having the mesopleuron and the propodeal side unsculptured between the punctures and the wing membrane conspicuously infumate (Fig. 1340), the specimens from Guam also in having the terga without silvery, apical fasciae or only tergum I with such a fascia, and those from Rota Island ( P. oakleyi rotaense ) in having the punctures of the frons microscopically small, practically indistinguishable from the remaining microsculpture. In P. westwoodii , the mesopleuron and the propodeal side are microsculptured between the punctures in most specimens (but unsculptured in some specimens from Koror Island and some from Pohnpei Island), the wing membrane is slightly infumate, the terga are silvery fasciate apically, and the punctures of the frons are minute but well defined.

DESCRIPTION.– Frons dull, minutely punctate, punctures more than one diameter apart. Distance between antennal socket and orbit slightly smaller than socket diameter. Gena narrow in dorsal view. Labrum shallowly 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 minute, 1-2 diameters apart; interspaces aciculate. Scutellum sulcate along anterior margin. Tegula not enlarged. Mesopleural punctures fine but well defined, about 1-2 diameters apart at center; interspaces unsculptured. Postspiracular carina present, about as long as midocellar diameter. Metapleural sulcus not costulate between dorsal and ventral metapleural pits. Propodeum with irregular longitudinal carina separating side from dorsum and posterior surface and extending from gastral socket area toward spiracle; dorsum either predominantly ridged (unridged only apicomesally), punctate between ridges, or predominantly unridged, minutely punctate (punctures 2-3 diameters apart), interspaces unsculptured; side minutely punctate, not ridged, interspaces unsculptured; posterior surface transversely ridged, punctate between ridges. Hindcoxal dorsum with outer margin sharply carinate at apex. Punctures of tergum I microscopically small, several diameters apart anterior to apical depression. Sterna punctate throughout, punctures several diameters apart at center of sternum II.

Setae silvery, appressed on upper frons, postocellar area, scutum, and tergum I; not concealing integument on clypeus; on lower gena straight (curved apically), suberect, markedly shorter than midocellar diameter. Terga without apical, setal fasciae or tergum I with ill-defined such fascia in population from Guam, but terga I and II in female, and I-IV in male silvery fasciate in this from Rota Island.

Body all black, mandible brown apically. Wing membrane markedly infumate (Fig. 1340).

♀.– Upper interocular distance equal to 0.50-0.54 × lower interocular distance; ocellocular distance equal to 0.2 × hindocellar diameter, distance between hindocelli equal to 0.3 × hindocellar diameter; eye height equal to 1.04-1.10 × distance between eye notches. Free margin of clypeal lamella roundly arcuate (Fig. 1338). Dorsal length of flagellomere I 2.2 × apical width, of flagellomere IX 1.2 × apical width. Mandible: trimmal carina with minute incision shortly beyond midlength. Length 7.0- 8.1 mm; head width 2.0- 2.2 mm.

♂.– Upper interocular distance equal to 0.68 × lower interocular distance; ocellocular distance equal to 0.3 × hindocellar diameter, distance between hindocelli equal to 0.6 × hindocellar diameter; eye height equal to 1.00 × distance between eye notches. Free margin of clypeal lamella angulate, about rectangular (Fig. 1339). Dorsal length of flagellomere I 2.0 × apical width, of flagellomere X 1.2 × apical width. Sternum III with basomedian tubercle in holotype (as described and illustrated by Krombein, 1949:407 and 1950:134), but simple in two specimens examined determined by him). Apical margin of sternum VIII broadly, shallowly emarginate (Fig. 1341). Genitalia: Figs. 1342, 1343. Length 5.6-6.8 mm; head width 1.6-1.7 mm.

GEOGRAPHIC VARIATION.– In the population from Guam, the punctures of the frons are minute but well defined, and at most gastral tergum I has a silvery, setal fascia. In specimens from Rota Island (described as P. oakleyi rotaense by Tsuneki, 1968b), the punctures of the frons are microscopically small and practically indistinghuishable from the surrounding microsculpture, and silvery fasciate are terga I and II in the female, and I-IV in the male. I cannot confirm the differences in the propodeum sculpture described by

Tsuneki (1968b).

GEOGRAPHIC DISTRIBUTION (Fig. 1344).–

Known only from Guam and Rota, two adjacent islands in the Mariana Archipelago.

RECORDS (Krombein, 1949 or as indicated).–

MARIANA ISLANDS: Guam: Haputo Point,

Machanao , Mount Alutom (1 ♀, USNM, allotype of

Pison oakleyi ), Mount Santa Rosa (1 ♂, CAS) ,

North Field , Pilgo River (1 ♀, CAS), Point Ritidian

( 4 ♀, BISH; 1 ♀, CAS; 1 ♀, USNM, paratype of

Pison oakleyi ), Talofofo, Tarague, no specific locality (1 ♂, USNM, paratype of Pison oakleyi ; 2 ♀,

1 ♂, BISH). Rota Island: Sabana , no specific local-

FIGURE 1344. Collecting localities of Pison oakleyi ity (1 ♀, 1 ♂, BISH, paratypes of Pison . oakleyi

Krombein.

rotaense Tsuneki).