Hybristodryinus viriosus Wang, Olmi and Gao, 2021

Wang, Zhen, Olmi, Massimo, Shih, Chungkun, Ren, Dong & Gao, Taiping, 2021, New species of Hybristodryinus from mid-Cretaceous Myanmar amber (Hymenoptera, Dryinidae), Cretaceous Research 125, No. 104861, pp. 1-6 : 2-4

Hybristodryinus viriosus Wang, Olmi and Gao , sp. nov.

LSID: urn:lsid:zoobank.org:act:79 A30209 -7D6E-4BAE-BA8B-31F7F 457D301

Etymology. The species is named after the Latin adjective viriosus (meaning, “strong”).

Material. Holotype: female. No. CNU-HYM-MA2015109 .

Diagnosis. Female of Hybristodryinus with occipital carina complete; antenna very slender, more than six times as long as head, reaching about second segment of metasoma; first flagellomere 19 times as long as broad; maxillary palpus very slender, with palpomere 4 about 20 times as long as broad.

Type locality and horiz on. The amber specimen was collected from Kachin ( Hukawng Valley ) of northern Myanmar, which was dated at 98.79 ± 0.62 Ma, earliest Cenomanian ( Cruikshank and Ko, 2003; Shi et al., 2012).

Description. Female ( Figs. 1 ̅ 3 ). Fully winged; length 6.7 mm ( Figs. 1A, 1B, 1C , 2A ). Head black, except clypeus and mandible testaceous; antenna testaceous; mesosoma black; metasoma brown; legs testaceous. Antenna 10-segmented, clavate, very slender, apparently hairless; lengths of antennomeres in following proportions: 20:8:46:36:29:19:14:13:10:12; antenna more than six times as long as head (200:33), reaching about second segment of metasoma. ADO's not visible. Flagellomeres much longer than wide; antennomere 9 about five times as long as broad (10:2); antennomere 3 about 19 times as long as broad (46:2.4).

Head slightly convex, with sculpture not distinct; clypeus with anterior margin rounded ( Figs. 2C, 2D, 2E ); mandible 4-dentate (progressively larger from dorsal to ventral tooth); frons slightly convex, not longitudinally excavated medially, with transverse fold situated half way, not reaching eyes laterally; occipital carina complete, bordered by furrow, not reaching eyes laterally; vertex without longitudinal keels connecting lateral ocelli to occipital carina; occiput deeply excavated; eye bulging, bare, much shorter than head (22:33); POL = 13; OL = 5 (but head partly crushed, so this measure is the average between right and left OL); OOL = 15; TL = 8; OPL = 4; greatest breadth of lateral ocelli much shorter than POL (4:13); frontal line absent. Maxillary palpus with six palpomeres, number of labial palpomeres not observable, palpal formula probably 6/?. Maxillary palpus very slender, with palpomere 4 about 20 times as long as broad (10:0.5).

Pronotum with deep anterior transverse impression between anterior collar and disc; disc humped, trapezoidal, not isosceles triangle shaped ( Figs. 2C, 2D ), not deeply longitudinally excavated medially; posterior collar absent; anterior surface of pronotum without longitudinal striae; sculpture of disc indistinct; pronotum longer than head (43:33); pronotal tubercle reaching tegula. Epicnemium present. Mesoscutum smooth, slightly shorter than pronotum (38:43). Notauli almost reaching posterior margin of mesoscutum ( Fig. 2D ); minimum distance between notauli slightly shorter than POL (10:13). Mesoscutellum with sculpture indistinct, shorter than mesoscutum (17:38). Metanotum shorter than scutellum (9:17), with sculpture indistinct. Metapectal-propodeal complex shorter than mesoscutum (30:38), reticulate rugose, areolae very wide, disc with posterior corners strongly projected posteriorly ( Figs. 1B , 2A ); propodeal declivity shorter than disc of metapectal-propodeal complex (10:20), indistinct, because hidden behind disc.

Fore leg ratio: 38 (coxa): 41 (trochanter): 60 (femur): 70 (tibia): 38 (tarsomere 1): 5 (tarsomere 2): 8 (tarsomere 3): 40 (tarsomere 4): 51 (tarsomere 5); enlarged claw shorter than protarsomere 5 (37:51) ( Figs. 1A, 1C , 3A, 3B, 3C ). Protrochanter very slender and long, with long and slender proximal stalk, broadened after half-way; protrochanter about 13 times as long as broad (41:3.2); protarsomere 3 produced into hook; rudimentary claw present, much shorter than enlarged claw (7:37); arolium much shorter than enlarged claw (6:37); enlarged claw with distal apex sharp, with two subapical teeth and one row of small lamellae (number of lamellae not distinct). Protarsomere 5 with two rows composed of many lamellae, one row formed by longer lamellae (number of lamellae indistinct); distal apex with group of lamellae (number of lamellae indistinct). Mid leg ratio ( Figs. 1A, 1C , 2A ): 28 (coxa): 30 (trochanter): 56 (femur): 56 (tibia): 40 (tarsomere 1): 17 (tarsomere 2): 11 (tarsomere 3): 7 (tarsomere 4): 10 (tarsomere 5). Mesotrochanter short and broad, less than three times as long as broad: 15:6. Hind leg ratio ( Figs.1A, 1C , 2A ): 44 (coxa): 13 (trochanter): 67 (femur): 50 (tibia): 46 (tarsomere 1): 24 (tarsomere 2): 16 (tarsomere 3): 9 (tarsomere 4): 16 (tarsomere 5).

Forewing hyaline, not darkened, with the usual venation of Dryininae ( Figs. 3D, E ); pterostigma much longer than broad (40:6), metacarp (PostabR1) shorter than pterostigma (25:40); marginal cell 2R1 open; stigmal veins (2r-rs & Rs) with distal part (Rs) much longer than proximal part (2r-rs) (39:21). The spurious vein of secondary nature that runs anterior of the claval furrow between cu-a and end of the 3-Cu. Forewing with usual three basal cells (costal (C), radial (R) and first cubital (1Cu)) clearly enclosed by pigmented veins. Hind wing not distinct.

Metasomal petiole very short, much shorter than rest of metasoma (7:145). Metasoma slightly longer than mesosoma (145:140). Tibial spur formula 1/1/2.

Male. Unknown.

Host. Unknown.

Remarks. Because protrochanter is about 13 times as long as broad and the disc of pronotum is not excised medially, the new species is similar to Hybristodryinus mon Perkovsky et al. (2019). The main difference between the new species and H. mon is that POL is much longer than OPL in H. viriosus and about as long as OPL in H. mon.

Based on the description of Hybristodryinus viriosus sp. nov., the keys to the females of Hybristodryinus from Myanmar amber published by Perkovsky et al. (2019), Tribull et al. (2020) and Olmi et al., 2021, must be modified by replacing couplet 7 as follows:

7. Protrochanter less than seven times as long as broad (greatest breadth) ¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨ H. cretacicus Perkovskyet al. (2019)

- Protrochanter about eight-thirteen times as long as broad (greatest breadth) ¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨ 8

8. Disc of pronotum deeply longitudinally excised medially ( Fig. 2A in Tribull et al., 2020) ¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨ ¨¨¨¨¨¨¨¨¨¨¨¨¨ H. moutesoe Tribull et al. (2020) .

- Disc of pronotum not excised longitudinally medially ( Figs 1B , 2D ) ¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨ 9.

9. Head with POL about as long as OPL ¨¨¨¨¨¨¨¨¨¨¨ ¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨ H. mon Perkovskyet al. (2019).

- Head with POL much longer than OPL ¨¨¨¨¨¨¨¨¨¨¨ ¨¨¨¨¨¨¨¨¨¨¨ H. viriosus Wang, Olmi and Gao , sp. nov.

Figures

Fig. 1. Photomicrographs and line drawing of Hybristodryinus viriosus Wang, Olmi and Gao, sp. nov., holotype ♀ CNU-HYM-MA2015109 preserved in Cenomanian-aged Myanmar (Burmese) amber. A. Ventral view. B. Dorsal view. C. Line drawing in ventral view. Antennae and legs are artificially extended from the body for easy recognition and comparison. Scale bars: 1.0 mm for A, B and C.

Fig. 3. Photomicrographs and line drawings of Hybristodryinus viriosus Wang, Olmi and Gao, sp. nov., holotype ♀ CNU-HYM-MA2015109.A. Ventral view of mesosoma and fore leg. B. Right chela. C. Line drawing of right chela. D. Forewing venation. E. Line drawing of forewing venation. Abbreviations: a, arolium; ec, enlarged claw; rc, rudimentary claw; T4, protarsomere 4; T5, protarsomere 5; Pt, Pterostigma. Scale bars: 0.4 mm for A, Band C; 1.0 mm for Eand F.

Fig. 2. Photomicrographs of Hybristodryinus viriosus Wang, Olmi and Gao, sp. nov., holotype ♀ CNU-HYM-MA2015109. A. Lateral view. B. Lateral view of head and mesosoma. C. Ventral view of head.D. Dorsal view of head and mesosoma. E. Anterior view of head. Abbreviations: mp, maxillary palpus; oc, occipital carina. Scale bars:1.0 mm for A; 0.4 mm for B, C, D and E.