Platystethynium (Platypatasson) earlyi Huber, 2021

Huber, John T. & Read, Jennifer, 2021, A new, remarkable species of Platystethynium (Platypatasson) (Hymenoptera: Mymaridae) from New Zealand, Zootaxa 5052 (2), pp. 215-232 : 217-218

Platystethynium (Platypatasson) earlyi Huber , sp. n.

( Figs 1 – 17 )

Type material. Holotype ♀ ( NZAC), dissected under 2 coverslips on slide ( Fig. 6 ) with three labels as follows: “ Platystethynium (Platypatasson) earlyi Huber Holotype ♀ dorsal”, “ New Zealand BR, Woods Creek Track, SE. of Greymouth, 180m 24.ii.2007, J.W. Early R.F. Gilbert ”, “Soil in old mining tunnel ex. rhaphidophorid egg L 15842 ”.

Paratypes. 2♀, 1♂ on slides, 14 ♀, 2♂ on cards ( CNC, NZAC) with same collecting data as holotype, and all from the same host egg. Platystethynium earlyi is the third species of the genus for which males are described .

Diagnosis. FEMALE. Females of Platystethynium earlyi are distinguished from P. fransseni , the only other described species of the subgenus in the Eastern Hemisphere, by the features given in the key and, in addition: gena in dorsal view more rounded posteriorly and eye relatively shorter compared to head length ( Fig. 2 ) (in P. fransseni , gena in dorsal view more angular posteriorly and eye relatively longer, Fig. 22 ); pronotum with 1 long submedial posterodorsal seta ( Fig. 4 ) (in P. fransseni with 2 shorter, more laterally placed posterodorsal setae, Fig. 25 ); fore wing with lobe posterior to parastigma forming a right angle with posterior margin of wing ( Fig. 5 ) (in P. fransseni forming an oblique angle, Fig. 24 ); fore wing with apex more rounded ( Fig. 5 ) (in P. fransseni apex more pointed, Fig. 24 ) and anterior row of microtrichia in basal half of wing distal to venation separated by a distinct gap from posterior row of a few very short microtrichia (in P. fransseni anterior row of microtrichia in basal half of wing distal to venation separated by a distinct gap from posterior row of almost equally long microtrichia); genitalia originating near midpoint of gaster ( Fig. 10b ) and about 1.9× as long as mesotibia (in P. fransseni genitalia originating near base of gaster ( Fig. 26b ), 3.0× as long as mesotibia) (metatibia not oriented well for measurement so comparison made with mesotibia instead of metatibia).

MALE. Males of P. (Platypatasson) earlyi are distinguished from the known males of other Platystethynium species by having the flagellum 10-segmented (11-segmented in P. fransseni ) and most flagellomeres wider than long ( Figs 14, 15 ) (longer than wide in P. triclavatum ).

Description. FEMALE. Body length 643–812 (n=13, card mounts), 785–900 (n=3, slide mounts). Colour. Body light brown except frenum, legs, and underside of mesosoma almost white; outer ovipositor plate and genitalia brown. Head. Width 158–162 (n=2), vertex with 1 short seta laterally about midway between median ocellus and transverse trabecula ( Fig. 2a ). Antenna. Funicle apparently without mps on any segment ( Figs 1, 3 ) but with 2 mps on clava segment 1 and 4 mps on clava segment 2. Funicle segments slightly increasing in width from fu 1 to fu 6 and each usually slightly longer than wide except for fu 6, which is slightly wider than long. Length/width measurements (ratios) (n=2): scape 116–118/32–34 (3.48–3.63), pedicel 50–52/24–30 (1.74–2.21), fu 1 22–24/18–19 (1.24–1.30), fu 2 24–26/20 (1.20–1.28), fu 3 23–24/18–20 (1.16–1.28), fu 4 22/20–22 (1.00–1.10), fu 5 21–23/21–24 (0.95–1.00), fu 6 22–24/24–30 (0.75–0.97), clava 109/34–41 (2.68–3.17). Mesosoma. Width 146–148 (n=2), scutellum with fairly long scutellar setae and sharply triangular fenestra ( Fig. 4 ). Wings. Fore wing (n=3) with anterior row of microtrichia in basal half of wing distal to venation separated by a distinct gap from posterior row of a few very short microtrichia ( Fig. 5 ); length 628–641, width 38–39, length/width 16.1–16.9, longest marginal setae 130–137. Hind wing length 622–629, width 26, longest marginal setae 122–149. Metasoma. Gaster with terga about equal in length and each with about 4 setae sublaterally and laterally near their posterior margins ( Figs 7a , 10a ). Ovipositor length 212–215, distinctly longer than metatibia length (175–182) and arising near base ( Fig. 7b ) or near apex of gt 4 ( Fig. 10b ).

MALE. Body length 782–822 (n=2, card mounts), ~800 (n=1) (slide mount, head measured separately from rest of body). Colour. Head, antenna, wing remnants, legs and metasoma almost white except as follows: gena except malar area brown, vertex light brown, mandible dark reddish brown, scape and pedicel light brown, mesoscutum, gt 1 and sterna light brown ( Figs 11, 12 ). Head. Width 265, distinctly wider than mesosoma (182); face about 3.5× as wide as high, smooth except with engraved reticulations laterally near torulus ( Fig. 13a ); each torulus slightly closer to mouth margin than to transverse trabecula and each preorbital trabecula much thinner than transverse trabecula; vertex smooth, slightly wider than long, with each supraorbital trabecula much thinner than transverse trabecula and not divided into segments; median ocellus absent; lateral ocellus small, about 0.3× diameter of a torulus and at posterolateral corner of vertex; eye small, in anterior view about 3.1× as high as wide, with few facets; gena large, in lateral view about 3.4× width of eye and with strong vertical rugae; back of head smooth ( Fig. 13b ); mouth opening huge, about 4.0× greatest diameter of foramen magnum. Entire head with very few, minute setae as follows: 1 on gena lateral to supraorbital trabecula, 1 medial to ventral apex of preorbital trabecula, 4? on malar area near lateral angle of mouth opening, 2 dorsolateral to foramen magnum. Mouthparts. Mandibles large, when closed overlapping for over half their length, each with 3 equal teeth ( Fig. 13a ). Antenna ( Figs 14, 15 ). Scape smooth, in lateral view about 0.5× as wide as long and almost twice as wide as pedicel; pedicel smooth, about 1.6× as long as wide, longer than any flagellomere and 0.5× as long as scape; flagellum 10-segmented, length 255 and less than head width, with 1 mps on fl 1 –fl 4 and apparently 1 or 2 mps on remaining flagellomeres, apical flagellomere the narrowest and tapering towards apex, with blunt or pointed apex (each antenna different), and with two apical setae about as long as basal width of flagellomere; length/width (ratios): scape 71/44 (1.62), pedicel 40/28 (1.41), fl 1 30/22 (1.36), fl 2 28/17 (1.60), fl 3 24/17 (1.37), fl 4 26/16 (1.65), fl 5 23/16 (1.49), fl 6 28/14 (2.00) and 26/16 (1.63), fl 7 18/14 (1.29), fl 8 22/14 (1.57) and 32/15 (2.13), fl 9 22/16 (1.37), fl 10 36/10 (3.5) (fl 6 and fl 8 have different dimensions so measurements for both antennae are given). Mesosoma ( Fig. 16 ). In dorsal view 1.5× as long as wide, width 182; propodeum slightly the widest segment; pronotum almost smooth, with trace of longitudinal reticulations, and longitudinally divided medially, in dorsal view clearly visible, in lateral view almost horizontal, with 1 minute anterior and 1 posterior submedian seta (or at least a sensillum) and 1 slightly longer posterior sublateral seta; mesoscutum slightly less than 1.5× as long as wide, smooth, with notaulus evanescent in posterior half, except with small shallow depression on anterior margin just lateral to notaulus, without adnotaular setae, and with 1 lateral seta just anterior to spiracle; mesoscutellum medially slightly shorter than mesoscutum, with scutellum 1.5× as long as strongly transverse frenum, with frenal line separating the two present only laterally; axilla with a minute seta on dorsal and lateral panels; scutellum with a seta at lateral margin about midway between anterior margin and frenal line; fenestra (only visible internally) occupying most of scutellum except for a narrow crescent along anterior margin; metanotum with dorsellum medially about 0.6× as long as frenum and about 3.8× as wide, as long and extending narrowly laterally along anterior margin of propodeum to lateral margin of lateral panel of metanotum; lateral panel of metanotum distinct, narrow medially, wider laterally, with a distinct pit along anterior margin midway between median and lateral margins, and with 2 minute setae at lateral margin in anterior and posterior corners; propodeum, smooth, about 0.4× as long as wide, with spiracle small and without propodeal seta. Wings. Reduced to minute translucent balloon-like vestiges with hind wing slightly larger than fore wing ( Fig. 16 , left side) and shorter than half length of tegula ( Fig. 16 , right side). Legs. Short, with femora stout, tibiae distally stout and not much longer than femora, and tarsi short, with tarsal segments 1 and 4 about as long as wide, and tarsal segments 2 and 3 shorter than wide ( Figs 11, 12 ). Metasoma. About 1.4× as long as mesosoma; petiole about 12× as wide as long and almost as wide as gt 1; gaster with all segments about equal in length and weakly sclerotized, collapsing in air dried specimens, truncate posteriorly with last visible segment in dorsal view almost as wide as gt 1 and without externally visible spiracle ( Fig. 11 ); each gastral segment apparently with 2 minute setae laterally along posterior margin. Genitalia. Capsule rectangular, about 0.4× as long as aedeagal apodemes + aedeagus ( Fig. 17 ).

Host. Rhaphidophoridae (Orthoptera) , unidentified to genus and species. The egg remains was preserved and glued to a card together with one of the P. earlyi females. The egg measured 4 mm in length and, though slightly crushed, measured about 1.7 mm in diameter. Its volume was calculated as 1.22825 mm 3. The volume of a female of P. earlyi was calculated as 0.0052 mm 3 so an estimated 24 individuals would have completely occupied the host egg. Given that the host egg is not cylindrical but somewhat oval and that the chorion thickness also would slightly reduce the egg internal volume, the maximum possible number of P. earlyi individuals that could have filled the egg completely would only be about 20, i.e., almost the same number as was actually reared from the egg. This indicates that the entire egg contents must have been used to feed the developing larvae of P. earlyi , whose bodies ultimately filled the egg completely. Though the egg chorion was somewhat torn, at least one hole and perhaps two or three holes were made, likely by at least one of the three males, for parasitoid emergence.

Derivation of species name. The species is named in honour of John W. Early, Curator (retired) of Entomology, Auckland Museum, Auckland, New Zealand, one of the collectors of the new species.

Distribution. New Zealand.

Figures

FIGURE 7. Platystethynium (Platypatasson) earlyi Huber, holotype. 7a, metasoma, dorsal; 7b, genitalia (seen through metasoma). Scale bars = 100 μm.

FIGURES 1–3. Platystethynium (Platypatasson) earlyi Huber, holotype. 1, habitus, ventral; 2, head, dorsal; 3, head, ventral. Scale bars: 1 = 200 μm; 2, 3 = 100 μm.

FIGURES 4–6. Platystethynium (Platypatasson) earlyi Huber, holotype. 4, mesosoma, dorsal; 5, wings; 6, holotype slide. Scale bars: 4 = 100 μm; 5 = 200 μm.

FIGURES 8–10. Platystethynium (Platypatasson) earlyi Huber, paratype female. 8a, head, lateral; 8b, head, lateral showing ocular apodeme; 9, mesosoma, lateral; 10a, metasoma, lateral; 10b, genitalia. Scale bars = 100 μm.

FIGURES 11, 12. Platystethynium (Platypatasson) earlyi Huber, paratype male. 11, mesosoma + metasoma, dorsal; 12, mesosoma + metasoma, ventral. Scale bars = 100 μm.

FIGURES 13–17. Platystethynium (Platypatasson) earlyi Huber, paratype male. 13a, head, anterior; 13b, head, posterior; 14, right antenna; 15, left antenna; 16, mesosoma, dorsal; 17, genitalia. Scale bars: 13, 17 = 50 μm; 14–16 = 100 μm.

FIGURES 22–24. Platystethynium (Platypatasson) fransseni (Ogloblin), paratype female. 22, head, dorsal; 23, antenna, lateral; 24. Wings. Scale bars: 22, 23 = 100 μm; 24 = 200 μm.

FIGURES 25, 26. Platystethynium (Platypatasson) fransseni (Ogloblin),paratype female.25, mesosoma,dorsal;26a, metasoma, dorsal; 26b, genitalia (seen through metasoma). Scale bars = 100 μm.