Brachymeria trinidadensis (Narendran & Varghese)

Binoy, C., Santhosh, S. & Nasser, M., 2022, First discovery of the Neotropical species Brachymeria trinidadensis (Hymenoptera: Chalcididae, Brachymeriinae) in India, Zootaxa 5092 (4), pp. 429-441 : 431-440

Brachymeria trinidadensis (Narendran & Varghese)

Thaumatelia trinidadensis Narendran & Varghese, 1989: 46‒47 , figs 12‒18; combination by Halstead, 1991: 952.

Type material. Holotype, ♀ (photographs examined, Figs 1–4 )—“ Holotype; Trinidad, Date ?, WI; Aug. Busck Collector; ♀ Thaumetelia trinidadensis SP. N, DET., NARENDRAN & THRESIAMA (VARGHESE), 1988; USNMENT 01559231” ( Fig. 5 ).

Narendran & Varghese (1989) listed the type locality as “ Trinidad ( Argentina)”, but the type labels indicate otherwise .

Condition of holotype. Pinned. Right wings absent, left scape (lost after initial imaging, Miles Zhang, pers. comm.).

Other specimen examined. ♀, mounted on triangular card ( Figs 6–16 )— India: Kerala, Kozhikode district, Elathur (11°19’32.5”N 75°44’30.8”E, 23.0 m above mean sea level), collected near subterranean tunnel of Bembix sp. , 25.vii.2020, coll. C. Bijoy.

Diagnosis. Among known described species, females of B. trinidadensis are uniquely characterized by a conspicuously long syntergum, comprising 0.4× the length of the metasoma ( Figs 1, 4 , 6, 8, 16 ) and being about 4.6× as long as its basal width in dorsal view ( Figs 4 , 8 ) or basal height in lateral view ( Figs 1 , 6, 16 ) in combination with the head lacking a transverse carina on the vertex posterior to the median ocellus ( Figs 3, 4 , 10, 11 ). Other diagnostic features include: metasoma more than 1.8× as long as combined length of head and mesosoma ( Figs 1, 4 , 6, 8 ); head with post-orbital carina indicated, not reaching genotemporal margin (hardly visible beneath dense pilosity); hind femur reddish brown with apical yellow patch ( Figs 1 , 6, 15, 16 ); hind tibia subbasally and apically yellow with remainder reddish brown ( Figs 1 , 6, 15 ).

Redescription based on Indian female ( Figs 6–16 ). Body length 5.52 mm; length of fore wing 2.79 mm.

Colour. Body black except as follows: eye reflective yellow; ocelli yellow; scape and pedicel reddish-brown; pleura dark brown; tegula yellow with base reddish-brown; coxae reddish-brown (hind coxa paler); fore and mid femora reddish-brown with yellow apical patch, hind femur reddish-brown with dorsoapical yellow patch; fore and mid tibiae yellow with median reddish-brown patch, hind tibia reddish-brown with subbasal and apical yellow patch; tarsi pale yellow; metasoma reddish-brown, but terga paler ventrally.

Head. Head in frontal view ( Fig. 9 ) 1.5× as long as wide; densely and coarsely rugose-punctate, sculpture hidden beneath dense white setae on lower face, the frons and vertex less setose; scrobal margin conspicuously produced, distinctly carinate; scrobe deep, surface rugose-reticulate; frons with strong, uneven carina between each eye and scrobe, but the two carinae not curved and continued mesad dorsally behind median ocellus ( Figs 10, 11 ); side of face without preorbital carina; post-orbital carina indicated, not reaching genotemporal margin ( Fig. 7 ); eye 3.1× as long as malar space in profile ( Fig. 7 ); head in dorsal view 1.1× as wide as mesosoma ( Figs 11, 12 ); OOL 3.0× POL; LOD 1.4× OOL ( Fig. 11 ); relative lengths of scape: pedicel: flagellomeres I to X (last) = 1.3: 0.3: 0.1: 0.4: 0.4: 0.4: 0.4: 0.4: 0.4: 0.4: 0.2: 0.5.

Mesosoma. Mesosoma dorsally mostly coarsely rugose-punctate with interstices reticulate, and each puncture with white seta arising from within it ( Figs 12, 13 ), but anteromedial margin of mesoscutal medial lobe posterior to pronotum bare, transversely impunctate-reticulate, and with lateral margins of medial lobe more foveate along notauli; scutellum with similar sculpture as medial lobe of mesoscutum, interspaces raised, apex slightly emarginate ( Fig. 12 ); propodeum coarsely rugate, spiracle subvertical; mesopleuron coarsely rugate, with anterior half setose but femoral depression bare; metapleura coarsely rugate and setose, more densely setose ventrally ( Fig. 13 ).

Hind leg. Hind coxa dorsally smooth, ventrally with setigerous pits; hind femur on outer disc reticulate with moderately dense pubescence, inner disc smooth, without inner basal tooth or protuberance, ventrally with nine well-separated irregular teeth ( Figs 15, 16 ).

Fore wing. Subhyaline with veins brown ( Figs 6, 8 ); MV 2.9× PMV, PMV 2.4× STV ( Fig. 14 ).

Metasoma. Metasoma ( Figs 6, 8, 16 ) 2.1× as long as combined length of head and mesosoma; Gt 1 smooth, Gt 2 –Gt 6 faintly rugose dorsally, laterally with thick vestiture; posterior margin of Gt 2 and Gt 3 straight; syntergum long, 0.4× as long as entire length of metasoma, 0.7× the combined length of the preceding terga, and 4.1× as long as Gt 6; ovipositor sheath slightly protruding, visible dorsally ( Fig. 16 ).

Variation compared to holotype. OOL 3.0× POL (vs. 3.7× in holotype); mesosoma coarsely rugose-punctate, interstices reticulate throughout (vs. mesosoma closely punctate, interstices rugose becoming smooth and shining at apex of scutellum); MV 2.9 × PMV (vs. MV 3.1 × PMV); posterior margin of Gt 2 and Gt 3 straight (vs. posterior margin of Gt 2 and Gt 3 emarginated; Gt 5 0.5× as long as Gt 6 in dorsal view (vs. Gt 5 0.2× as long as Gt 6 in dorsal view); metasoma gradually tapering after Gt 2 (vs. metasoma conspicuously convex at maximum height, abruptly declining posteriorly); metasoma 2.1× as long as combined lengths of head and mesosoma (vs. metasoma 1.8× as long as combined lengths of head and mesosoma).

Distribution. Neotropical ( Trinidad and Tobago); Oriental ( India) (present report).

Host. Unknown, but the female was collected near a tunnel with a larva of an unidentified species of Bembix ( Hymenoptera : Crabronidae ) feeding on an unidentified species of Tabanidae (Diptera) .

Remarks. Using the key of Burks (1960) to species of the subgenus Pseudobrachymeria , the Indian female keys to Brachymeria (Pseudobrachymeria) laetiliae ) in having similar colour and sculpture, but although the female syntergum is acuminate it is not conspicuously elongate ( Figs 17, 20 ). The Indian female also resembles B aculeata (Walker) ( Figs 22, 24–26 ) in general appearance, but the latter has the hind tibia more extensively yellow with only basal and ventromesal brown patches ( Fig. 25 ); further, the vertex has a transverse carina posterior to the median ocellus in addition to vertical carinae on the frons so the head has a complete, inverted U-shaped carina ( Fig. 24 ).

Type images of the holotype of B. kraussi (Narendran & Varghese) ( Figs 27‒31 ) are similar to those of the lectotype of B. aculeata ( Figs 22, 24‒26 ), and the latter bears a label by M.T. Tavares dated 1995 suggesting that B. kraussi is junior synonym of B. aculeata , though this proposed synonymy has never been validated in the literature. Present comparison of the types images of B. kraussi and B. aculeata substantiate that both have a similar hind tibia colour pattern ( Figs 22, 25 , 27 ) and an inverted U-shaped carina on the head ( Figs 24 , 28 ). However, the holotype of B. kraussi differs from the lectotype of B. aculeata in having subparallel scrobal margins ( Fig. 30 ) rather than curved margins that converge dorsally toward the median ocellus ( Fig. 24 ), the syntergum 0.8× the combined length of the preceding metasomal terga ( Figs 27, 31 ) compared to 0.6× the combined length of the preceding metasomal terga ( Figs 22, 26 ), and the mesoscutum with large round punctures well separated by sculptured interspaces ( Fig. 29 ) compared to the mesoscutum being rugose-punctate with very narrow interspaces ( Fig. 26 )). Hence, we do not formally synonymize the two names at this time.

Brachymeria trinidadensis is differentiated from B. grisselli ( Figs 33, 35–37 ) in having a much longer syntergum (0.7× vs. 0.4× as long as the combined length of the preceding metasomal terga); hind tibia reddishbrown with subbasal and apical yellow patch (vs. hind tibia yellow with basal and ventromedial brown patch, Fig. 33 ); mesonotum with a different sculpture pattern (cf. Figs 12 , 29 ); and fore wings hyaline (vs. fore wings infumate, Figs 33, 37 ).

Brachymeria trinidadensis is differentiated from B. producta ( Figs 38, 40–43 ) in having a much longer syntergum (0.7× vs. 0.4× as long as the combined length of the preceding metasomal terga and 3.96× vs. 1.64× as long as Gt 6); hind tibia reddish-brown with subbasal and apical yellow patch (vs. hind tibia yellow with medial brown patch not extending dorsally); cercus on syntergum much closer to anterior margin (vs. cercus on syntergum near half length, Fig. 38 ).

Brachymeria trinidadensis is differentiated from B. westwoodi (Bouček, 1992, figs 76–78) in having eyes glabrous (vs. eye sparsely setose); spiracle of Gt 6 normal (vs. spiracle of Gt 6 raised, produced backwards); hind femur ventrally with nine well-separated irregular teeth (vs. hind femur ventrally with 13 well separated teeth).

Brachymeria trinidadensis is differentiated from B. bicolor ( Girault, 1912) (Bouček, 1992, fig. 75) in having spiracle of Gt 6 normal (vs. spiracle of Gt 6 placed dorsally on a raised hump); hind femur ventrally with nine wellseparated irregular teeth (vs. hind femur ventrally with eight teeth); hind tibia reddish-brown with subbasal and apical yellow patch (vs. hind tibia yellow with median brownish black patch).

Brachymeria trinidadensis is differentiated from B. pyramidea ( Bouček & Delvare 1992, figs 60–65) in having hind femur ventrally with nine well-separated irregular teeth (vs. hind femur ventrally with 14 teeth); hind tibia reddish-brown with subbasal and apical yellow patch, (vs. hind tibia dorsally (except base) yellow); wings hyaline (vs. wings subinfumate); notauli shallow (vs. notauli unusually deep); syntergum 4.1× Gt 6 (vs. syntergum 1.9× Gt 6).

Figures

FIGURES 1–5. Brachymeria trinidadensis (Narendran & Varghese, 1989). Holotype ♀: 1, habitus, lateral view; 2, head, frontal view (arrows indicate uneven frontal carina); 3, head, dorsal view (arrow indicates absence of transverse carina on vertex); 4, habitus, dorsal view; 5, type labels.

FIGURES 6–16. Brachymeria trinidadensis. Female from India: 6, habitus, lateral view; 7, head and antenna, lateral view (arrow indicate post-orbital carina partly visible through dense pilosity); 8, habitus, dorsal view; 9, head, frontal view; 10, head, fronto-dorsal view (arrows indicate uneven frontal carina); 11, head, dorsal view (arrow indicates absence of transverse carina on vertex); 12, mesosoma, dorsal view; 13, mesosoma, lateral view; 14, fore wing venation; 15, hind leg; 16, metasoma, lateral view (arrow points to cercus on syntergum).

FIGURES 17–21. Brachymeria laetiliae Burks, 1960. Holotype ♀: 17, habitus, lateral view; 18, head, frontal view (arrow indicates almost non-existent traces of frontal carina); 19, head, dorsal view (arrow indicates absence of transverse carina on vertex); 20, habitus, dorsal view; 21, type labels.

FIGURES 22–26. Brachymeria aculeata (Walker, 1862). Lectotype ♀: 22, habitus, lateral view; 23, type labels; 24, head, frontal view (arrows point to inverted U-shaped carina); 25, hind leg; 26, habitus, dorsal view.

FIGURES 27–32. Brachymeria krausii (Narendran & Varghese, 1989). Holotype ♀: 27, habitus, lateral view; 28, head, dorsal view (arrows point to inverted U-shaped carina); 29, head and mesosoma, dorsal view; 30, head, frontal view; 31, metasoma, dorsal view; 32, type labels.

FIGURES 33–37. Brachymeria grisselli (Narendran & Varghese, 1989). Holotype ♀: 33, habitus, lateral view; 34, type labels; 35, head, frontal view (arrows point to remnants of carinae between eye and scrobe); 36, head, dorsal view (arrow points to remnant of carina between eye and scrobe); 37, head and mesosoma, dorsal view.

FIGURES 38–43. Brachymeria producta (Olivier, 1791). Neotype ♀: 38, habitus, lateral view (arrow points to cercus on syntergum); 39, type labels; 40, head and mesosoma, dorsal view; 41, head, frontal view; 42, habitus, dorsal view; 43, hind leg.