Platystethynium (Platystethynium) onomarchicidum Ogloblin, 1946

Huber, John T. & Read, Jennifer, 2021, A new, remarkable species of Platystethynium (Platypatasson) (Hymenoptera: Mymaridae) from New Zealand, Zootaxa 5052 (2), pp. 215-232 : 225-229

Platystethynium (Platystethynium) onomarchicidum Ogloblin, 1946

Platystethynium) onomarchicidum Ogloblin, 1946: 291 ; holotype ♀ (USNM). Type locality: Indonesia, Java, Bogor. Triapitsyn, 2018: 159 (comparison with P. glabrum ).

Platystethynium glabrum Jin & Li, 2016: 204 , syn. n. Holotype ♀ (NEFU). Type locality: China, Yunnan, Mannanxing.

Remarks. Platystethynium glabrum , originally described from only one specimen and later recorded and illustrated from Taiwan by Triapitsyn (2018) and India by Sankaraman et al. (2020), is placed here in synonymy under P. onomarchicidum . Jin & Li (2016) recognized that P. glabrum was “obviously closely related to P. onomarchicidum .” The diagnostic features they presented do not work, either because they appear to be common to all P. ( Platystethynium ) species or they are wrongly described, e.g., the ocelli do not form a right angled triangle, as also stated (wrongly) by Ogloblin (1946), and there are a very few short setae among the eye facets. Triapitsyn (2018) also noted several incorrect statements in the P. glabrum description. The ratios given are not so different from those of P. onomarchicidum specimens that they could be considered sufficient to recognize two (or more) species instead of one, variable species. The propodeum in P. glabrum is stated to be relatively shorter than in P. onomarchicidum (0.49× instead of 0.57× the frenum length) and the ovipositor of P. glabrum originates at the level of tergum 4, as illustrated by Jin & Li and Sankaraman et al. (2020). Specimens of P. onomarchicidum in the CNC have the ovipositor originating at the level of tergum 2, 3 or 4 and the ovipositor length is ~0.64–0.75× the gaster length (0.84× gaster length in P. glabrum ). The ovipositor length in two paratypes is 2.81 and 3.11× metatibia length, and in two non-type specimens is 2.61–2.78× metatibia length. Triapitsyn (2018) recorded the ovipositor length as 1.8× metatibia length in a specimen he identified as P. glabrum from Taiwan. In an otherwise similar specimen of Platystethynium (Platystethynium) sp. from Thailand he reported the ovipositor length as 2.3× metatibia length. He also measured non-type specimens from the same series as the types of P. onomarchicidum and recorded the ovipositor as about 3.0× metatibia length. He supposed that the ovipositor in P. onomarchicidum could be subject of significant intraspecific variability, but because material at his disposal was limited he did not place P. glabrum in synonymy under P. onomarchicidum . Jin & Li (2016) did not use the ratio of ovipositor length/metatibia length but it can be calculated from the scale bars and images of the holotype of P. glabrum , i.e., the ovipositor length is 2.37× as long as metatibia length. The greatest variation among all the above specimens is in ovipositor length, with the two nontype specimens about midway between the ratio given for the paratypes of P. onomarchicidum and the holotype of P. glabrum . Jin & Li (2016) gave the scape length/width of P. glabrum as ~2.64 and compared it to the scape length/width ratio from Ogloblin (1946) but his ratio is wrong, as one can determine if one measures his illustration of the scape; it is 2.69× not 1.85× as long as wide, which is almost identical to that of P. glabrum . A paratype (CNC) of P. onomarchicidum was measured to confirm the ratio. No other differences between P. glabrum and P. onomarchicidum are known so the above synonymy is confidently made.

Host. The only know host so far is Onomarchus uninotatus (Serville) ( Tettigoniidae : Pseudophyllinae ), an Oriental species with a range extending from India to Australia, so it is not surprising that P. onomarchicidum is also widespread and shows some intraspecific variation.

Material examined. LAOS: Houa Phan, Phou Pane Mt. , 1480-1510 m, 20°13'09"–19°Ν 103°59'54"– 104°00'03"E, 1-16.vi.2009, V. Kubáň (2 ♀, CNC) . PHILIPPINES: Cavite, Indang, Petronio coffee farm, 14°09.20'N 120°54.40'E, 1508', 2.iv.2011, H. Ngo, Malaise trap (1 ♀, CNC) . TAIWAN: Pintung, Kenting Nat. Park , 200-230 m, 17-23.v.1991, C.K. Starr & M. Wu, secondary forest, Malaise trap (2 ♀, CNC) . THAILAND: Chiang Mai, Amphur Mae , 250 m, 15.42°Ν 98.49°Ε, 1-31.i.1998, R. Snelling, forest, Malaise trap (1 ♀, CNC) ; Nakhon Nayok, Khao Yai Nat. Park , evergreen trail near training centre, 14°24.482'N 101°22.388'E, 755 m, 26.ii-5.iii.2007, Malaise trap, W. Sukho; Uthai & Tak, Huai Kha Khaeng [Wildlife Sanctuary], 400 m, iii.1986, M.G. Allen (1 ♀, CNC) .

Distribution. India, Indonesia, Laos, Philippines, Taiwan, Thailand. Rameshkumar et al. (2015) reported an unidentified Platystethynium from Meghalaya, northeastern India. Their habitus image is definitely that of P. onomarchicidum so India is included in the list of countries.