Thaumatodryinus fuscescens, Martins & Melo, 2020

Martins, Andre L. & Melo, Gabriel A. R., 2020, Revision of the fossil species of Thaumatodryinus Perkins from Dominican amber, with a new combination and description of a new species (Hymenoptera, Dryinidae), Journal of Hymenoptera Research 79, pp. 77-88 : 77

† Thaumatodryinus fuscescens sp. nov.

Figure 1

Diagnosis.

Thaumatodryinus fuscescens sp. nov. is characterized by the body predominantly testaceous, except head and part of pronotum and remainder of mesosoma black; eyes hemispherical, about 1.1 × longer than wide; maximum head width about 1.9 × distance between inner margins of tegulae; frontal line present; mid portion of clypeus with anterior margin straight; antenna with 1st flagellomere as long as 2nd; POL 3.2 × OL; OOL about 6 × OPL; occipital carina complete; notauli percurrent, extending from anterior to posterior margins of mesoscutum.

Description.

Female holotype (Fig. 1A-F ). Approximate body length: 4.1 mm. Color. Head black, except mandible, clypeus and antenna testaceous (Fig. 1A-D ); pronotum black, except dorsal-posterior surface brown (Fig. 1B ); mesosoma black; legs testaceous, except pro- and metafemur with middle portion darkened (Fig. 1 ); fore wing with one transverse darkened band; metasoma testaceous. Pubescence. Head with short setae (Fig. 1A-C ); antenna with setae; eye glabrous (Fig. 1C ); pronotum with fine and erect setae (Fig. 1B ); mesosoma with conspicuous erect setae (Fig. 1B ); propodeum with erect setae; metasoma with more conspicuous erect pilosity on last tergum. Integumental sculpture . Head finely granulated (Fig. 1A-C ); frontal line in the form of a low carina and apparently complete, not visible near mid ocellus; malar sulcus well-marked; mandible with a marked groove at the base; pronotum granulate, except by rugosity on lateral portions of transverse impression; mesoscutum granulate; notauli complete; mesoscutellum rugulose, its anterior margin with a narrow row of small foveae, not with a groove; mesopleuron rugose; metapleuron reticulate-rugose; propodeum reticulate rugose. Structure and proportions. Vertex convex, except by ocellar triangle slightly elevated. Ocellar ratio: POL = 16; OL = 5; OOL = 25; OPL = 4; TL = 9. Antennomeres in following proportions: 35: 15: 45: 45: 60: 65: 55: 23: 27: 25. Eye hemispherical, about 1.1 × longer than wide; maximum head width about 1.9 × distance between inner margins of tegulae; occipital carina complete; mid portion of clypeus with anterior margin straight; maxillary palpomeres elongated; malar space about as long as basal width of mandible; notaulus complete (Fig. 1B ). Head longer than pronotum (60:55); mesoscutum longer than mesoscutellum and metanotum shorter than propodeum. Fore wing with three cells closed by pigmented tubular veins; vein abscissa 3Rs&4Rs longer than 2r-rs (65:30). Dorsal surface of propodeum distinctly longer than posterior surface (50:45); mesopleuron with a groove in the central region. Articles of fore leg (Fig. 1E-F ) in the following proportions: 54 (coxa): 50 (trochanter): 63 (femur): 80 (tibia), 46: 8: 15: 34: 50 (tarsomeres 1-5), and 46 (enlarged claw). Segment 3 of protarsus with four long bristles and segment 4 with five long bristles. Chela (Fig. 1E-F ) and enlarged claw with two subapical teeth and one row of about 26 lamellae. Segment 5 of protarsus with two rows of at least 40 lamellae; distal apex with group of approximately seven long lamellae.

Remarks.

Thaumatodryinus fuscescens sp. nov. is more similar to the extant Neotropical fauna than to the other two species found in the Dominican amber. It has in common with some of the living species a convex vertex and slightly elevated ocellar triangle, straight lower clypeal margin, complete occipital carina, percurrent notauli and anterior margin of mesoscutellum with a narrow row of small foveae. Among the fossil species studied here, T. fuscescens sp. nov. is more similar to T. miocenicus and differs from T. priscus by the head shape with eyes protuberant on the lateral side, frontal line present and ratio of OL short than TL. The new species differ from T. miocenicus and T. priscus by the granulated integument of the head; clypeus with lower margin straight; 1st flagellomere as long as 2nd; hemispherical-shaped eyes; and percurrent notauli. The chela of T. fuscescens is closed and for this reason it is not possible to determine the number of lamellae in the enlarged claw and in the 5th tarsomere.

Etimology.

The species is named in reference to its overall dark coloration, from the Latin fuscus, dark, dusky, and - escens, beginning of, becoming.

Type material.

Holotype female, in amber from the Dominican Republic (piece DZUP Dom-018). According to the amber dealer, it is probably from La Toca or Los Cacaos mine, in Santiago de los Caballeros.

Figures

Figure 1. † Thaumatodryinus fuscescens sp. nov., female holotype. A habitus, dorsal view B right antenna, dorsal view C head and mesosoma, antero-ventral view D head and mesosoma, dorsal view E apical portion of flagellum, with details of flagellomeres 5 - 8 F-G Apical portion of fore leg, with details of the chela. Scale bars: 2 mm (A), 0.5 mm (B), 0.5 mm (C-D), 0.3 mm (E-G).