Nososticta hedigeri, Theischinger & Mitchell & Richards & Polhemus, 2023

Theischinger, Günther, Mitchell, Andrew, Richards, Stephen J. & Polhemus, Dan A., 2023, Systematics of the Nososticta salomonis complex (Odonata: Zygoptera: Platycnemididae), Zootaxa 5296 (2), pp. 101-146 : 122-124

Nososticta hedigeri sp. nov.

( Figs 34–41 , 59, 60 , Map 1 , Pl. 4)

Holotype. ♁, SAMA 07-001675 , Papua New Guinea, Bougainville, Pipikei (5.8077° S, 154.8067° E; 240 m a.s.l.), 17–19-x-2019, S. Richards; deposited in the South Australian Museum, Adelaide, Australia.

Paratypes. 2 ♁♁, 3 ♀♀, SAMA 07-001673 , 07-001676 , 07-001674 , 07-001677 , 07-001678 , same data as holotype; deposited in the South Australian Museum, Adelaide, Australia. 2 ♁♁ (No. 313), RMNH.INS.1153719 , 1153720 , S Bougainville , Buin, 1930, H. Hediger; supposedly in Basel, but sent from RMNH; 1♁, 1♀, RMNH. INS.1153721 , 1153722 , Bougainville, S. Nasiooi, Agric. Field St. , 19-v-1976, HR Wimmer ex USNM; deposited in Naturalis Biodiversity Center Leiden, Netherlands .

Etymology. The species is dedicated to its probable discoverer, Heini Hediger (1908–1992), a Swiss biologist noted for work in proxemics in animal behaviour and known as the "father of zoo biology". It is a noun in the genitive case.

Description of holotype

Head. Largely black; only base of labium pale grey and a transverse frontal bar from eye to eye blue; an ill-defined pale brown mark only barely detectable between antennal base and lateral ocellus.

Thorax. Pronotum black, anterior lobe with one blue lateral patch on one side, two on the other, smaller inner patch separate; much larger outer patch connected to large patch of same colour on median lobe; propleura largely blue, some black anteriorly, along part of sutures and at rear of epimeron. Synthorax with pleura largely black; blue restricted to: ante-humeral patch, distinctly longer than ½ the length of mesanepisternum, drop-shaped with inner margin sloping from long wide base to humeral suture, leaving black area between two ante-humeral patches approximately cup-shaped with distinct narrow basal stalk; patch covering dorsal 4/5 length, rarely more, and almost entire width of mesepimeron; partly connected with it a stripe across whole length and anterior 3/4 of metepisternum; patch across most of metepimeron, subbasally to basally shortened by black along metapleural suture extending to poststernum, its anterior margin almost straight; posterolateral tip of meso- and metakatepisternum. Postcoxae blackish brown to black and blue; poststernum pale blue with separate narrow elongate ill-defined patches of blackish brown to black. Legs: Coxae largely blue, anterobasally brown to black, trochanters black and blue, legs otherwise black, with only base of femora, longest in metafemur, pale bluish grey. Wings: Membrane with slight greenish brown tinge, venation black; pterostigma black, slightly more than twice as long as wide; postnodals 16–17/13.

Abdomen. S1 dorsally black, laterally largely blue; S2 largely black, blue adjacent to genitalia but blue dorsal mark absent; S3–7 dorsally black, ventrally narrowly margined greyish brown, S3–6 with blue mid-dorsal spot very close to base; S8 largely blue, narrowly lined black basally, more widely and irregularly apically, also a very fine black midline over part of the blue patch; S9 and S10 black. Superior anal appendages largely blue, inferiors brownish black.

Dimensions. Hind wing 19.1 mm; abdomen (including anal appendages) 33.2 mm.

Description of female

Head. Much as in male, but dark structures and areas darker, pale areas largely pale yellow to very pale blue; brownish mark between antennal base and lateral ocellus more distinct.

Thorax. Pronotum much as in male, but anterior lobe with larger outer mark only, bluish white and connected to large patch of same colour on median lobe; posterior lobe with vertical dorsal and horizontal ventral lobe; propleura much as in male but pale areas largely bluish white instead of blue. Synthorax with pleura largely black; pale yellow to whitish blue areas include: ante-humeral patch, less than 40% length of mesanepisternum, comma-shaped; mesepimeral patch reduced to tiny remnant, completely fused with stripe across whole length of and anterior 2/3 to 3/4 of metepisternum; a subtriangular to subtrapezoidal patch across most of metepimeron; posterolateral tip of meso- and metakatepisternum. Postcoxae blackish brown to black and pale greyish yellow; poststernum pale greyish yellow with largely narrow elongate patches of dark greyish brown to black. Legs: coxae largely pale to brownish yellow, anterobasally brown to black, trochanters black and pale brownish yellow; legs otherwise dark, with meso- and metafemur partly to largely greyish to pale brownish yellow and tibiae, except for apical portion, brightened to pale and darker yellowish brown. Wings: membrane with very slight greenish brown tinge, venation black; pterostigma black, slightly more than twice as long as wide; postnodals 15–18/12–15.

Abdomen. S1 and S2 dorsally largely black, laterally largely pale blue; S3–7 dorsally black, ventrally narrowly margined pale greyish yellow, S3 and S4, sometimes also S5, with very short pale blue dorsal mark very close to base and most commonly divided into two spots by dark midline; S8 black with ventral edge yellow; S9 and S10 black. Anal appendages yellow, inferior anal lamina brown and yellow; ovipositor dull yellow, valves (about 12 teeth) brown to black; supra-anal plate black.

Dimensions. Hind wing 17.5–20.5 mm; abdomen 26.2–31.5 mm.

Variation in the male paratypes. Inner margin of dorsal region of ante-humeral patch varying between almost straight and sloping and widely or irregularly curved toward humeral suture; black elongate median and lateral patch of poststernum separate or narrowly connected; postnodals 15–17/12–14; hind wing 18.6–20.4 mm; abdomen (including anal appendages) 28.5–34.2 mm.

Affinities. Based on the present study ( Fig. 6 ), N. hedigeri sp. nov. is considered sister species to N. salomonis .

Differential diagnosis. Nososticta hedigeri sp. nov. can be distinguished from all other species of the N. salomonis complex by having the male ante-humeral patches extending very close to the mid-dorsal carina basally, leaving only a narrow black stalk between them, versus a much wider black stalk, and the very short female ante-humeral patches extending slightly inward basally making them appear comma-shaped, versus more parallel sided and often also markedly longer.

Distribution and habitats. This species is currently known only from Bougainville Island at the western edge of the Solomon Islands Archipelago ( Map 1 , Pl. 4), where it is common along clear-flowing streams in primary and partially degraded lowland and hill forest.

Figures

MAP 1.—Distribution of species of the Nososticta salomonis complex in the Solomon Islands.

FIGURE 6. Bayesian tree from concatenated (all genes) data set. Numbers above branches are BI posterior probabilities and ML bootstrap values shown only if ≥ 0.9 and 70%, respectively.

FIGURES 34–41. Nososticta hedigeri sp. nov. (34–37) male: (34) in life; (35, 36) synthorax: (35) lateral; (36) schematically; (37) superior anal appendage; (38–41) female: (38) in life; (39, 40) synthorax: (39) lateral; (40) schematically; (41) antehumeral patch, frontal, 2 additional specimens.

FIGURES 55–65. Nososticta species. (55, 56) male abdominal segment 2, dorsal: (55) N. africana (Schmidt); (56) N. tagula sp. nov.; (57–65) synthorax, schematically: (57) N. africana (Schmidt), female; (58) N. tagula sp. nov., female; (59, 60) N. hedigeri sp. nov.: (59) male; (60) female; (61, 62) N. stueberi sp. nov.: (61) male; (62) female; (63) N. chrismulleri Theischinger & Richards, male; (64, 65) N. boonei sp. nov.: (64) female; (65) male.