Platygaster baltica, Buhl, 2021

Buhl, Peter Neerup, 2021, A distinct new species of Platygaster from Latvia (Hymenoptera: Platygastridae), Acta Biologica Universitatis Daugavpiliensis 21 (1), pp. 33-35 : 33-35

Platygaster baltica sp. nov.

( Fig. 1-4 )

Holotype ♀: Latvia / forest 10 km SW of Jēkabpils / 23.VIII.-26.IX.2010 / Malaise trap, P.N. Buhl ( ZMUC) .

Derivatio nominis: Named after the supranational region of the type locality.

Diagnosis: Occiput with longitudinal and oblique lines posteriorly, transverse anteriorly; frons smooth except for median carina; female A1 longer than height of head, A9 1.33 times as long as wide; notauli nearly complete; scutellum low and smooth; fore wing 2.2 times as long as wide; female metasoma hardly as long as rest of body, with T1 hardly 0.4 as wide as T2 which is smooth.

Description: ♀. Total body length 1.25 mm. Black; legs more or less pale brown, meso- and metafemora and distal half of metatibiae darkest; A1-A6 and mandibles medium brown, A1-A6 lighter ventrally; A7-A10, coxae and tegulae dark brown (procoxae somewhat lighter).

Head in dorsal view ( Fig. 1 ) 1.9 times as wide as long, about as wide as mesosoma; occiput with a longitudinal median carina from posterior margin over most of its length, obliquely carinate laterad of median carina, laterally vertically striated, anteriorly transversely striated, without hyperoccipital carina but two rather coarse, most anterior, transverse striae just behind ocellar area. Vertex finely pustulated. OOL:POL:LOL = 2.8:7.0:3.0. Frons smooth except for three transverse wrinkles just above antennal insertions, between these with a median longitudinal carina extending four-fifths of the way towards depression in front of anterior ocellus; frons also with an irregular row of setae along inner orbits. Compound eyes large, in lateral view higher than wide (11:7), 2.9 times as high as malar space, with sparse and very short interfacetal setae. Head in frontal view wider than high (22:18). Antenna ( Fig. 2 ) with A1 longer than height of head (19:18), 1.35 times as long as distance between inner orbits. Measurements of antennomeres A1-A10 (length: width) = 19.0:3.0; 4.8:1.9; 2.2:1.5; 3.8:2.3; 3.0:2.0; 3.0:2.0; 3.3:2.8; 4.0:3.0; 4.0:3.0; 6.0:2.7. Flagellar setation short but distinct.

Mesosoma 1.4 times as long as wide, slightly higher than wide. Lateral sides of pronotum with pustulate microsculpture in about anterior half, smooth in posterior half except for raised hair-sockets. Mesoscutum with a few setae along notauli and margins, smooth; mid lobe in anterior half and lateral lobes along narrow anterior margin and in posterior third pustulated leathery; admedian lines weakly indicated on anterior two-fifths of disc, parallel; notauli strong, ending shortly before anterior margin, posteriorly well separated; mid lobe ending bluntly, distinctly prolonged, covering extreme base of scutellum. Scuto-scutellar grooves rather narrow, each covered by five long setae. Mesopleuron smooth. Scutellum ( Fig. 3 ) slightly raising above level of mesoscutum, evenly and weakly convex, moderately densely setose. Metapleuron with pilosity all over. Propodeal carinae parallel; area between them smooth, about 1.2 times as long as wide.

Forewing slightly shorter than total body length (74:75), 2.2 times as long as wide, surpassing tip of metasoma by a distance equal to about 3.5 times combined length of T3-T6, clear, with dense and rather long microtrichia; marginal cilia 0.06 width of wing. Hindwing slightly more than five times as long as wide (creased in type), with two hamuli; marginal cilia one-quarter the width of wing.

Metatibia about 0.85 times as long as tarsus, the basal segment of which is 0.45 as long as metatibia, two-thirds as long as tarsal segments 2-5 combined.

Metasoma ( Fig. 4 ) 0.95 as long as rest of body, 1.8 times as long as wide, 1.7 times as wide as high, 0.95 as wide as mesosoma. Measurements of tergites T1-T6 (length: width) = 6.5:7.5; 25.0:20.5; 1.0:19.5; 1.0:18.5; 1.0:15.0; 3.0:10.0. T1 smooth, with two strong longitudinal carinae which are slightly converging from anterior margin to midlength of segment, then becoming parallel, laterally of two strong carinae with two weaker, incomplete carinae in anterior part on each side inside lateral margins, segment with only a few setae standing out from sides. T2 with two smooth basal foveae, these margined at lateral slopes of fovea to 0.25 length of tergite; foveae with a few long hairs, between them with very short crenulae; T2 otherwise smooth except for faint micropunctation along narrow posterior margin. T3-T6 dull, with pustulate microsculpture all over, and with a few setae in superficial punctures: two on T4, six on each of T5-T6. Sternite 1 and anterior 0.2 of sternite 2 with dense whitish setation; sternite 2 not convex anteriorly in profile.

Differential diagnosis: Similar to P. martikaineni Buhl, 2003 known from North and Central Europe, but that species has the occipital sculpture transverse, the frons smooth, in most of lower one-third with the transverse reticulation, OOL:LOL = 2:3, A1 shorter than the height of the head, and the flagellar segments shorter (A9 as wide as long). P. baltica sp. nov. runs to P. oscus Walker, 1835 , known from North Europe, also from Latvia (probably even east to Mongolia), in Vlug’s (1985) key, but that species has the occiput strongly transversely striated, the frons with superficial striation, and T1 hardly less than half as wide as T2. In Buhl’s (2006) key P. baltica sp. nov. could also run to P. soederlundi Buhl, 1998 , known from North and Central Europe (and east to Korea), but that species has the occiput with the weak, irregular, transverse sculpture, and A9 as wide as long. Undoubtedly, P. baltica sp. nov. is an interesting discovery and a specifically characteristic species primarily due to the head sculpture in the combination with the conformation and the sculpture of particularly the metasoma.

Figures

Fig. 1-4. Platygaster baltica sp. nov. holotype female 1 – head from above; 2 – antenna; 3 – scutellum and propodeum in lateral view (propodeum to the right); 4 – metasoma from above.