Vanuatubasis xanthochroa, Saxton & Marinov & Bybee, 2022

Saxton, Natalie A., Marinov, Milen G. & Bybee, Seth M., 2022, Revision of Vanuatubasis Ober & Staniczek, 2009 (Odonata, Coenagrionidae), with description of seven new species, ZooKeys 1128, pp. 129-169 : 129

Vanuatubasis xanthochroa sp. nov.

Figs 11 , 21J

Type material.

Holotype (1 ♀ NZAC). "Republic Of Vanuatu, Malekula Island, | Stretch of Lakatchkach River flowing through Postanie Area | 16.1437S, 167.4671E; 15 m a.s.l. | 17 May 2017 | M. Marinov & S. Bybee leg." " Vanuatubasis sp.2., female | M. Marinov det., August 2017" "NZ Arthropod Collection | Private Bag 92170 | Auckland | New Zealand | NZAC04230976".

Paratypes (2 ♀♀ BPBM, 5 ♀♀ BYU, 3 ♀♀ NHM, 4 ♀♀ NZAC). (2 ♀♀ BPBM, 4 ♀♀ BYU, 3 ♀♀ NHM, 3 ♀♀ NZAC) "VANUATU: Malekula Is: | Litslits, -16.14594705 | 167.4653247, 18, 24.v.2018 | coll. S. Bybee and G. Powell." (1 ♀ BYU, 1 ♀ NZAC) "VANUATU: Malekula Is., | Litslits, May 7th 2019 | -116.1435, 167.4671 | Coll:SM Bybee, GS Powell | VU-BYU-2019".

Description of holotype.

Head: Labium pale yellow; labrum, mandibles (except for the reddish tips), whole clypeus, frons and genae along the eyes up to the dorsal ends of the scapes, scapes and pedicels citron yellow except for a dull fulvous (to pale brownish) spot at the middle of the labrum along its posterior edge with triangular shape and two fuscous spots at the postero-lateral corners of the labrum; flagella dark red; scape: pedicel 0.5; vertex black with slight dark red sheen with three yellow spots - two are expansions of the yellow face into the dark vertex and the third is just in front of the median ocellus; rear part of the head yellow which is continuing up toward the occipital area and visible from the dorsum on the posterior ends of postocular lobes and occipital bar; two roughly circular occipital spots formed by pale pruinescence; eyes orange yellow with pale fulvous areas on the dorsal part; eyes with three transverse lines in right eye and one in left which are unclear if are post mortem or present in life.

Thorax: Entire thorax including the legs yellow with pale fulvous area starting from the dorsal part of the thorax and diffusing around the level of mesepimeron; five dark spots as follows: two faint sitting on the dorsal end of mesopleural and metapleural sutures (metapleural very obscure) almost touching the posterior corners of both sutures; two dark red at the dorsal posterior corners of both mesepimeron and metepimeron and one at the posterior end of the poststernum; leg spines deep dark red to almost black, claws fulvous becoming darker at the tips; mesostigmal plate, roughly quadrilateral-shaped with expanded dorsoanterior side thus wider than ventral side; hind lobe of the prothorax raised, roughly triangular shape with two parallel carinae, dorsal angulated and ventral rounded arising out from the lateral sides of the hind lobe, running posteriorly to the dorsal edge.

Wings: Hyaline; venation generally dark especially at the distal ends becoming paler towards the bases with pale spots at the nodus at the outer sides; pterostigma rhomboidal fulvous with pale yellow lines along the edges that are wider on the dorsal edge and faint to almost not existing at the anterior edge; CuP halfway between antenodals in front wings and closer to second antenodal in hind wings situated proximally to the wing petiolation and distant from the point where CuP and AA is leaving the wing edge for nearly a whole of its length; arculus distal from the second antenodal in all wings; discoidal cells dissimilar in shape - in front wings anterior side is ~ 1/4 of the posterior and in hind wings anterior side is ~ 1/2 of posterior; three postdiscoidal cells before nodus; nodal index: 12/2-2/11 in front wings and 10/2-2/11; MA, MP and CuA very long reaching to surpassing the midway between nodus and pterostigmas.

Abdomen: Generally dark fulvous on the dorsum and pale yellowish on the ventral side with the following peculiarities: fulvous dorsal area is very faint to almost missing on S1 and gradually becoming darker towards the posterior end finishing abruptly at ~ 1/4 of S9, remainder of S9 and S10 pale cream with a touch of a faint blue on the dorsum, dorsum of S10 at the intersegmental membrane to S9 with a very narrow dark red bar not continuing on the lateral sides of the segment; dorsum of S2-S7 with anterior part paler, becoming darker at the posterior ~ 1/6-1/7 end of the segments, all with yellow bars at the anterior end continuing from the venter and almost touching on the dorsum, S8 uniformly dark; small tooth at the posterior end of the eight sternite; cerci pale yellow; ovipositor orange yellow surpassing the posterior end of S10 with the tip aligned with the tips of cerci and styles surpassing the cerci.

Measurements (in mm): total length 33.5, abdomen 28.0, hind wing 20.5.

Diagnosis.

Female. Vanuatubasis xanthochroa can be distinguished from all other Vanuatubasis females by the lack of a black dorsal stripe across the carina and no postclypeal maculation.

Variation.

Female. Dark spot on the labrum larger; both eyes with transverse lines; posterior end of the posterior edge of the prothorax triangular shape and not as wide as in the holotype; CuP situated at the petiolation at the base of CuP and AA where the later leaves the wing edge, pterostigma with yellow lines all around the edges, nodal index: 11/2-2/11 in front wings and 9/2-2/9 in hind wings, spine on the ventral side of eight sternite large and sharp.

Distribution.

Malekula, Vanuatu

Etymology.

The name Vanuatubasis xanthochroa is Latinized feminine form of Greek ξανθόχρους, - ους, - ουν = yellow colored, in reference to the color of the thorax {declinable adjective}.

Notes.

This species is only known from female specimens as no males were able to be associated.

Figures

Figure 11. Vanuatubasis xanthochroa Holotype (♀ NZAC) A dorsal thorax B lateral terminalia. Scale bars: 0.5 mm.

Figure 21. Female face and dorsal terminalia of A V. bidens B V. discontinua C V. evelynae D V. insularivorum E V. kapularum F V. malekulana G V. nunggoli H V. rhomboides I V. santoensis J V. xanthochroa.