Nixonia Masner

van Noort, S. & Johnson, N. F., 2009, New species of the plesiomorphic genus Nixonia Masner (Hymenoptera: Platygastroidea, Platygastridae) from South Africa., ZooKeys 20, pp. 31-51 : 34

Nixonia Masner

urn:lsid:zoobank.org:act:E56C690B- 55E 3-4977-B7CF-6493DEF 73E 6C

Nixonia Masner, 1958: 101 . Original description. Type: Nixonia pretiosa Masner , by monotypy and original designation. For subsequent taxonomic literature see Johnson(1992) or The Genera of Platygastroidea of the World (http://purl.oclc.org/ NET/hymenoptera/platygastroidea).

Diagnosis. Nixonia is superficially similar to Scelio Latreille, and to the larger, more elongate species of Macroteleia Westwood and Triteleia Kieffer. Nixonia is distinguished by the 14 segmented, nonclavate antennae; the strong medial propodeal tooth; and the presence of two tibial spurs on both the mid-and hind tibiae.

Distribution. Nixonia species richness is centered in southern Africa, but distribution extends north to Egypt, Kenya, Somalia, Rwanda, and the Democratic Republic of Congo (former Zaire). A single species, N. krombeini , is found in Sri Lanka, northern India, and southeast Asia (Thailand, Laos, and Vietnam). See http://hol.osu.edu/ map-large.html?id=523 for distribution map.

Biology. Only one species has been reared: Nixonia watshami a parasitoid of the eggs of A. discoidalis (Walker, 1869) (Orthoptera: Tettigoniidae, Hetrodinae ). The subfamily Hetrodinae is endemic to Africa and adjacent areas of the Arabian Peninsula ( Otte et al. 2009) and all 14 genera are likely to play hosts for Nixonia species. The host, however, of at least N. krombeini which occurs outside the range of Heterodinae in tropical Asia must be some other large orthopteran ( Johnson and Masner 2006).

Key to species of Nixonia

Online interactive Lucid matrix and Lucid Phoenix keys are available at: http://www. waspweb.org/Platygastroidea/Keys

1 Third antennal segment shorter than, or subequal to, second antennal seg- - Third antennal segment longer (>1.15x) than second antennal segment.........5

- Femora and tibiae reddish brown to black; eye height less than twice shortest distance between eyes..................................................................................4

3 Medial portion of posterior margin of pronotum, scutellar rim, tegulae, propodeal tooth, margins of tergites 1-4, and tarsi yellow; upper mesepisternum punctuate; Namibia............................................................... N. flavocincta

- Mesosoma, metasoma black without yellow markings, tarsi dark brown; upper mesepisternum longitudinally striate; Namibia....................... N. sicaria

4 Forewings extending to middle or posterior margin of tergite 4; female metasoma with tergites 2-4 brick red, mid- and hind femora and tibiae reddish brown; South Africa................................................................. N. corrugata

- Forewings longer, extending nearly to posterior margin of tergite 5; female body and legs entirely black; South Africa..................................... N. stygica

5 Third antennal segment only slightly longer (1.15x) than second antenn segment .....................................................................................................6

- Third antennal segment significantly longer (1.4-3.1x) than second antennal segment......................................................................................................7

6 Occipital carina not developed; female tergite 6 irregularly carinate; female body and legs entirely black; South Africa.................................. N. elongata

- Occipital carina massive; female tergite 6 longitudinally carinate; female metasomatic segments 2-5 brick red; legs, except coxae, reddish orange; South Africa, Botswana.................................................................... N. pecki

7 Maxillary palpomere 4 cylindrical; mandible long, with lower tooth either absent or much shorter than upper, base of mandible with dense tuft of thick setae......................................................................................8

- Maxillary palpomere 4 with strongly expanded lateral lobe, width of palpomere nearly equal to its length; mandible short, bidentate, lower tooth only slightly shorter than upper, base of mandible without dense tuft of thick setae..........................................................................................................10

8 Mandible unidentate, with no indication of lower tooth; legs orange-yellow; Somalia............................................................................................. N. bini

- Mandible with short, but distinct lower tooth; legs black............................9

9 Mesoscutum and scutellum with irregular, sharply defined rugulosities, with small setigerous punctures scattered over surface; tegula reddish brown, distinctly lighter in color than mesoscutum; Egypt......................... N. priesneri

- Mesoscutum and scutellum covered by deep, confluent, large setigerous punctures; tegula black, concolorous with mesoscutum; Angola, Congo, Kenya, Malawi, Rwanda, Zimbabwe................................................. N. atra

10 Propodeal tooth cordate to subcordate, sides convex, longitudinally carinate, with or without medial depression; scutellum longitudinally striate; female tergite 6 deeply, emarginate posteromedially; large, 9 mm in length; South Africa.......11

- Propodeal tooth with sides straight, and pointed or ligulate, usually with deep medial depression; scutellum areolate-punctate; female tergite 6 with only shallow emargination posteromedially; moderate in size, 5-7 mm in length......12

11 Fore- and midtibiae with numerous stout, semi-erect, dark spines over outer surface; propodeal tooth without depression; female tergite 6 deeply, narrowly emarginate posteromedially, lateral flanges narrow.................. N. gigas

- Fore and midtibiae at most with small, semi-appressed spines; propodeal tooth with posterior-medial depression; female tergite 6 with deep, broad emargination posterio-medially, lateral flanges wide and conspicuous....... N. mcgregori

12 Eye height distinctly greater than shortest distance between eyes; mesoscutum with scattered punctures and wide interstices with dense mat microsculpture; India, Laos, Sri Lanka, Thailand, Vietnam.............................. N. krombeini

- Eye height sub-equal to, or only slightly greater, than shortest distance between eyes; mesoscutum with dense large punctures and narrow interstices with shining surface; Africa.......................................................................13

13 Shortest distance between eyes 0.9x eye height; forewing with several streaks of heavy infuscation; body length 7-10 mm; South Africa........................14

- Shortest distance between eyes equal to eye height; forewing with only moderate streaks of infuscation; body length 5-0-5-5 mm...............................15

14 Mesoscutum wider than long; scape elongate (3x longer than wide); dense field of setae obvious on vertex in anterior view; pronotal shoulders rounded----------------------------------------------------------------------------- N. lamorali

- Mesoscutum as wide as long; scape expanded (2.5x longer than wide); setae sparse on vertex; pronotal shoulders subquadrate ------------------------ N. masneri

15 Mesosoma, antennae, and legs entirely dark brown to black; Botswana, Namibia, Zimbabwe..................................................................... N. watshami

- Pronotum, mesonotum, antennomeres 1-3, and legs beyond coxae deep orange to reddish brown; Namibia.................................................N. pretiosa