Hybristodryinus castaneus Olmi, Guglielmino & Chen, 2021

Olmi, Massimo, Chen, Hua-Yan, Shih, Chungkun, Mueller, Patrick, Capradossi, Leonardo, Ren, Dong, Perkovsky, Evgeny E. & Guglielmino, Adalgisa, 2021, New species of Hybristodryinus Engel (Hymenoptera, Dryinidae) from mid-Cretaceous amber of northern Myanmar, with notes on their possible hosts, Journal of Hymenoptera Research 81, pp. 43-55 : 43

Hybristodryinus castaneus Olmi, Guglielmino & Chen sp. nov.

Figure 1

Diagnosis.

Male: macropterous, with antennomere 9 about six times as long as broad (Fig. 1E ); face without long deep longitudinal furrow (Fig. 1D ); posterior margin of vertex not deeply excavated medially (Fig. 1C ); lateral ocelli not touching occipital carina; notauli complete, posteriorly separated (Fig. 1C ).

Description.

Male. Macropterous (Fig. 1A, B ); length 1.4 mm. Completely dark brown. Antenna filiform, about as long as body, with setae very short. Scape about as broad as pedicel. Antennomeres in following proportions: 5:4:8:9:9:9:8:8:6:7. Antennomere 9 about six times as long as broad (Fig. 1E ). Head with sculpture not visible; face without long deep median longitudinal furrow; mandible with teeth not visible; frontal line not visible; occipital carina complete, laterally not reaching eyes; ocellar ratio: POL:OL:OOL:OPL = 1:1:2:1; temple more than twice as long as OOL (5:2); greatest breadth of lateral ocellus as long as OOL; posterior margin of vertex not excavated medially (Fig. 1C ); occiput deeply excavated. Palpal formula 6/3. Mesosoma much longer than head (30:10) and metasoma (30:20). Pronotum with lateral regions not protruding. Mesoscutum shiny, with sculpture not visible, slightly shorter than head (9:10), much longer than mesoscutellum (9:5). Notauli complete, posteriorly separated (Fig. 1C ); minimum distance between notauli longer than OOL (3:2). Mesoscutellum shiny, with sculpture not visible. Metanotum and metapectal-propodeal complex not visible. Epicnemium not visible. Mesopleuron not visible. Fore wing hyaline, without dark transverse bands (Fig. 1F ). Stigmal vein (2r-rs&Rs) with angle between proximal and distal parts, with distal part much longer than pterostigma (12:8). Second radial 1 cell (2R1) open. Pterostigma much longer than broad (9:2). Metacarpus (PostabR1) slightly shorter than pterostigma (7:9). Fore leg ratio:? (coxa not visible, because it is hidden by an air bubble): 5 (trochanter): 16 (femur): 12 (tibia): 8 (protarsomere 1): 3 (protarsomere 2): 3 (protarsomere 3): 2 (protarsomere 4): 4 (protarsomere 5). Protrochanter more than four times as long as broad (5:1). Mid leg ratio: 7 (coxa): 4 (trochanter): 17 (femur): 15 (tibia): 9 (mesotarsomere 1): 3 (mesotarsomere 2): 2 (mesotarsomere 3): 1.5 (mesotarsomere 4): 3 (mesotarsomere 5). Mesotrochanter more than twice as long as broad (4:1.5). Hind leg ratio: 8 (coxa): 4 (trochanter): 17 (femur): 21 (tibia): 10 (metatarsomere 1): 4 (metatarsomere 2): 3 (metatarsomere 3): 2 (metatarsomere 4): 3 (metatarsomere 5). Tibial spurs 1/1/2.

Female. Unknown.

Material examined.

Holotype: male (DAF3869), Myanmar: specimen in mid-Cretaceous Burmese amber (about 99 Ma). Obtained from a mine situated in Northern Myanmar, Kachin State, Tanai Township , Hukawng Valley , SW of Tanai City (DAF).

Etymology.

The species is named Hybristodryinus castaneus (Latin adjective meaning “brown”) because of its dark brown colour.

Remarks.

H. castaneus is similar to H. konbaung Perkovsky, Olmi, Müller & Martynova, 2019, known from Burmese amber, for the following characters: face without a long deep longitudinal furrow, lateral ocelli not touching the occipital carina, posterior margin of the vertex not excised medially, notauli complete and separated posteriorly. However, the antenna of H. castaneus is slenderer, with antennomere 9 about six times as long as broad (less slender in H. konbaung , with antennomere 9 about twice as long as broad). Perkovsky et al. (2019) indicate "pronotum with lateral regions protruding" among the characters of the generic diagnosis. However, this character is not visible in all known males (as in H. pyu Perkovsky, Olmi, Müller & Martynova, 2019) and it is not present in H. castaneus sp. nov. (see description above). Except this character, H. castaneus meets with all other generic diagnosis characters of Hybristodryinus . Therefore, we update the diagnosis of the genus by excluding this character.

Figures

Figure 1. Hybristodryinus castaneus sp. nov., male, holotype A habitus, dorsal view B habitus, ventral view C head and mesosoma, dorsal view D head and mesosoma, ventral view E antenna F fore wing.