Vanuatubasis discontinua, 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 discontinua sp. nov.

Figs 3 , 21B

Type material.

Holotype (1 ♀ NZAC). (NZAC04230977, New Zealand Arthropod Collection, Auckland, New Zealand), locality data: Malekula Island, Litslits (-16.1460, 167.4653; 45 m a.s.l.): 24 May 2018; S. Bybee & G. Powell leg.

Paratypes (5 ♀♀ NZAC). Malekula Island: 1♀ (NZAC04231068), Losinwei (-16.1079, 167.3273, 29 m a.s.l.), 06 May 2019; 3♀♀ (NZAC04231069-71), Brenwe (-16.083, 167.275; 180 m a.s.l.), 22 May 2019; 1♀ (NZAC04231072), Wiaru River (-16.0787, 167.2726; 188 m a.s.l.), 13 May 2019); all S. Bybee & G. Powell leg.

Additional material

(1 ♀ NZAC). Malekula Island , Stretch of Lakatchkach River flowing through Postanle Area (-16.1437, 167.4671 to -16.1474, 167.4649; 15-51 m a.s.l.): 17 May 2017; M. Marinov & S. Bybee leg.

Description of holotype.

Head: Labium pale yellow; labrum, mandibles (except the reddish tips), clypeus and frons up to the midline between antennal bases and genae along the eyes up to dorsal level of scapes yellow with darker spots as follows: dull fulvous spot (to pale brown) along the posterior edge of the labrum; on postclypeus three areas with darker centers and diffused edges which connect to each other and with a transverse bar at the middle dorsal surface forming a T-shaped structure and dark fuscous to dark reddish at the dorsal corners of the mandibles at the ends of the lateral proximal corners of the postclypeus plus lateral sides of labrum running down for almost the whole length to the anterior edge; scapes yellow, pedicels pale brownish, flagella missing, scape: pedicel 0.3; vertex black with slight dark red sheen with a dull yellow spot in front of the median ocellus; rear part of the head yellow continuing up to occipital area and visible from the dorsum, yellow almost fully interrupted dorsally on the occipital bar between the postocular lobes except a small elongated spot in the middle area.

Thorax: Dark wide parallel sided bar with slight reddish sheen passing on the dorsal part of pro- and pterothorax encompassing ¾ of the dorsal part of the mesostigmal plate and 2/3 of mesepisternum with a faint light line on the posterior edge of the middle prothoracic lobe and dorsal carina, at the posterior ends the dark area curves ventrally towards the mesopleural suture with its edges making two consecutive semicircles joining the suture at its very posterior ends; dark elongated spots with same color developed also as follows: one oblique occupying the upper part of the mesinfraepisternum, two sitting on the dorsal edges of the meso- and metapleural sutures at their posterior ends and faintly connecting to two dark shiny spots at the alar areas by a tiny bridge with the same color; legs almost entirely yellow saved for the faint barred dorsal area on all femora (very weakly developed to almost invisible on the front legs and darken like a dashed line towards the hind legs), dark spots at the joints between femora and tibiae and all the leg spines, claws orange with darker reddish tips; mesostigmal plate roughly triangular shape with tip wide rounded to almost straight; posterior edge of posterior edge of the prothorax dorsal edge interrupted at the middle.

Wings: Hyaline; venation generally dark especially at the distal ends becoming lighter towards the bases with pale spots at the nodus at the outer sides; pterostigma elongated rhomboidal light fulvous to almost transparent; CuP approximately halfway between antenodals in all wings situated very closely to the wing petiolation almost at the point where CuP ad AA is leaving the wing edge; arculus originates at the second antenodals in front wings and slightly distal to it in hind wings; discoidal cells dissimilar in shape - in front wings anterior side is ~ 1/3 of the posterior and in hind wings anterior side is slightly longer than 1/2 of posterior; nodal index: 12/2-2/12 in front wings and 10/2-2/11 in hind wings.

Abdomen: Almost uniformly dark fulvous on the dorsum from S1 to S9 with yellow developed as follows: isosceles triangular spot on at the base of S1, all segment from S3 to S7 with lines at the base coming from the ventral and continuing up to almost meeting at the dorsum with yellow fainting in intensity towards the posterior segments; dark on S9 occupies a little more than 1/3 on the dorsal part, descends laterally and ends at the posterior end of the segment as a very faint dark area, rest of S9 beige on the dorsum; S10 dark base as deep reddish line overarching the dorsum and descending towards the venter, rest of dorsum beige; ventral side of the abdomen yellow except for: narrow dark lines running on almost entire length of the ridges of the sternites 2 to 8 (slightly to widely expanded on second and eight segments respectively); cerci pale brownish; posterior end of sternite 8 ending in a very low blunt tooth; ovipositor orange yellow aligned with the posterior end of S10 and styli surpassing the posterior ends of the cerci by 1/5 of their length.

Measurements: total length 38.5, abdomen 32.0, hind wings 23.5.

Diagnosis.

Female. Vanuatubasis discontinua is characterized with pale yellow ground color with dark markings on the thorax and dorsal part of the abdomen. It can be distinguished from other congeners where females exhibit similar type of coloration at various stages of their life (e.g., V. bidens , V. rhomboides sp. nov.) by the following combination of characters: long pedicel (scape: pedicel <0.5), maculation on postclypeus present and brown cerci.

Variation.

Female. Greatest variations observed on the shape of the markings on the postclypeus where the T-shaped structure could be reduced to two isolated spots. Dorsal carina along the posterior edge of prothorax not interrupted in two specimens. Dark elongated spots on the mesinfraepisternum diffused in most specimens and missing in one paratype. Two paratypes with pale markings on the dorsum of S9 close to the posterior end of the segment. Ovipositor surpassing S10 in one specimen.

Measurements (mm): total length 35.0-38.0, abdomen 29.5-31.5, HW length 21-23 (n = 5).

Distribution.

Malekula, Vanuatu.

Etymology.

The specific epithet for this species is derived from the modern Latin word discontinuus, - a, - um = discontinuous, referring to the interrupted dorsal carina on the prothorax (declinable adjective).

Notes.

This species is only known from female specimens as no males were able to be associated. One female was excluded from the type material as it generally resembles the paratypes, but has the following differences: (1) posterior edge of the middle lobe of prothorax with incision having bilobed shape, (2) elongated spot on mesinfraepisternum darker than other paratypes, (3) dorsum of S10 with a diffused longitudinal bar joining the posterior end of the segment enclosing two pale spots, (4) smaller size than paratypes: total length 30.5, abdomen 25.2, HW length 19.5.

Figures

Figure 3. Vanuatubasis discontinua 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.