Nososticta boonei, 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 : 120-122

Nososticta boonei sp. nov.

( Figs 30–33 , 64, 65 , Map 4 , Pls 3, 9)

Holotype. ♁, BPBMENT 000008199 , Papua New Guinea, Gulf Province, Isaba Creek off Sirebi River , SE of Omo, ~ 40 km N of Kikori, 40 m a.s.l., 7°12’48”S, 144°15’51”E, water temp. 27° C, 2-iii-1995, CL 7005, D.A. Polhemus; deposited in the Bishop Museum, Honolulu, Hawaii.

Paratypes. 2 ♁♁, 2 ♀♀, BPBMENT 0000081200–81203 , 4 ♁♁, 1♀, BPBMENT 2008035011-35015 , same data as holotype; deposited in the Bishop Museum, Honolulu, Hawaii. 2 ♁♁ ( SAMA 07-001690 – 91 ) , 1 ♀ ( SAMA 07-001692 ), Papua New Guinea, Gulf Province, Wau Creek, (7.1216°S, 144.3739°E; 20 m a.s.l.), 22–25-iv-2017, S. Richards; deposited in the South Australian Museum, Adelaide, Australia .

Etymology. Nososticta boonei sp. nov. is dedicated to the late Jim Boone (1942–2021), Bishop Museum collection manager, who took excellent care of preparing and exporting odonate material including this species for the present study. It is a noun in the genitive case.

Description of holotype. Note: Some available specimens, including the holotype, apparently turned paler by the way of preservation (ethanol), meaning that in particular the larger now pale greyish blue areas would have been largely bright blue in life (see Pl 9 for the colour in dried specimens).

Head. Largely black; only base of labium pale grey and a transverse frontal bar from eye to eye pale greyish blue.

Thorax. Pronotum black with larger whitish blue outer mark on anterior lobe connected to large whitish blue lateral patch on median lobe, a smaller inner mark separate; pleura largely whitish blue, black along suture and at rear of epimeron. Synthorax: pleura largely black with the following pale greyish blue: ante-humeral patch, very slightly longer than 1/2 the length of mesanepisternum, basally approximately twice as wide as dorsally, inner and apical margin almost straight (tip truncate); a patch covering about dorsal 4/5 length of mesepimeron, and partly connected with stripe across whole length and anterior 4/5 of metepisternum, and patch across approximately postero-dorsal 3/4 of metepimeron. Postcoxae largely blackish brown to black; poststernum bluish white with ill-defined patches of blackish brown to black. Legs: Coxae and trochanters bluish grey and black, legs otherwise black, with only extreme base and inner portion of basal 1/2 of metafemur pale bluish to pale and brownish yellow. Wings: Membrane with greenish brown tinge, venation black; pterostigma black, hardly more than twice as long as wide; postnodals 18/14.

Abdomen. S1 dorsally black, laterally largely pale bluish; S2 largely black, pale bluish to greyish yellow adjacent to genitalia; S3–7 dorsally black, ventrally margined greyish brown to dull yellow, S3–6 with blue mid-dorsal mark, about as long as wide, very close to base; S7 with pair of small not very well-defined bluish antero-dorsal spots narrowly connected across mid-line, followed by vaguely detectable diffusely bluish area; S8 largely blue, narrowly lined black basally, more widely and irregularly apically; S9 and S10 black. Anal appendages: Superiors largely blue, inferiors brownish black.

Dimensions. Hind wing 19.2 mm; abdomen (including anal appendages) 32.7 mm.

Description of female

Head. Much as in male, but dark structures and areas darker, pale areas largely pale greyish yellow instead of pale greyish blue.

Thorax. Pronotum much as in male but anterior lobe with larger outer mark only, which is barely connected to large mark of same colour on median lobe, posterior lobe with vertical dorsal and horizontal ventral lobe; propleura much as in male but pale areas largely pale greyish yellow instead of pale greyish blue. Synthorax: pleura largely black with pale greyish yellow as follows: ante-humeral patch, very slightly longer than 1/2 the length of mesanepisternum, very narrowly almond-shaped to almost parallel sided, 1/5 to 1/4 as wide as long; a tiny remnant of a mesepimeral patch completely fused with stripe across whole length and anterior 2/3 to 3/4 of metepisternum; subtriangular patch across approximately postero-dorsal half of metepimeron continuing narrowly along posteroventral half of it; extreme posterolateral tip of meso- and metakatepisternum. Postcoxae blackish brown to black and pale greyish yellow; poststernum pale greyish yellow with narrow elongate patches of dark greyish brown. Legs: Coxae largely pale greyish yellow, anterobasally brown to black, trochanters black and pale greyish yellow, legs otherwise black, with only very base of femora and part of basal 3/4 of metafemur pale greyish yellow. Wings: Membrane rather clear, venation black; pterostigma black, slightly more than twice as long as wide; postnodals 16/13–14.

Abdomen. S1 and S2 dorsally black, laterally largely pale greyish yellow; S3–7 dorsally black, ventrally margined greyish brown to dull yellow, a pale greyish blue dorsal mark very close to base, approximately semicircular on S3– 6, more elongate, between 1/3 to 1/2 the length of segment, on S7; S8 black, with or without 2 tiny greyish yellow spots on each side, ventrally margined dull yellow; S9 and S10 black. Anal appendages pale greyish blue, inferior anal lamina brown; supra-anal plate and valves brown to black; ovipositor greyish brown with tip greyish yellow.

Dimensions. Hind wing 19.6–20.0 mm; abdomen 29.5–30.5 mm.

Variation in the male paratypes. Postnodals 15–17/13–14. S7 with pair of small ill- to well-defined, separated antero-dorsal spots, posterior to them a diffusely bluish area may or may not be detectable. Hind wing 19.2–19.3 mm; abdomen (including anal appendages) 31.5–33.0 mm.

Affinities. Analysis of the two nuclear genes suggest that N. boonei sp. nov. is closely related to, yet distinct from, N. chrismulleri , in close agreement with the morphological evidence. The COI gene, in contrast, places N. boonei sp. nov. as closest to N. stueberi sp. nov.

Differential diagnosis. Nososticta boonei sp. nov. is a mainland (New Guinea) species as opposed to the almost exclusively insular species N. africana , N. tagula sp. nov., N. hedigeri sp. nov. and N. salomonis . The lack of a pale dorsal marking on segment 2 distinguishes the male of N. boonei sp. nov. from N. africana and N. tagula sp. nov., and the lack of a long black basal stalk between the ante-humeral patches distinguishes it from N. hedigeri sp. nov. The presence of a blue dorsal pattern element on S7 (vs. absent) separates N. boonei sp. nov. from N. salomonis . The male of N. boonei sp. nov. from Gulf Province is morphologically and genetically most similar to N. chrismulleri from Western Province. It can be distinguished from that species by having the inner and apical margin of the blue ante-humeral patch and the anterior margin of the blue metepimeral patch in males almost straight (vs. curved/sinuous in N. chrismulleri ). Nososticta boonei sp. nov. can be separated from N. stueberi sp. nov. by the markedly longer ante-humeral stripe and by the presence of a blue dorsal pattern element on S7 (vs. absent).

Distribution and habitats. Nososticta boonei is currently known only from lowland and foothill forests in the Kikori River basin in Gulf Province, southern-central Papua New Guinea ( Map 4 , Pl. 3) where adults perch on twigs and low foliage in sunny patches along small to wide (> 5 m), clear-flowing rocky and sandy streams. Material from the adjacent Purari River basin also probably belongs to this species.

Figures

MAP 4.—Distribution of species of the Nososticta salomonis complex on mainland New Guinea.

FIGURES 30–33. Nososticta boonei sp. nov. (30–32) male: (30) in life; (31) synthorax, schematically; (32) superior anal appendage; (33) female, synthorax, schematically.

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.