Mythicomyia dominicana Evenhuis

Evenhuis, Neal L., 2002, Review of the Tertiary microbombyliids Diptera: Mythicomyiidae in Baltic, Bitterfeld, and Dominican amber, Zootaxa 100, pp. 1-15 : 8-10

Subfamily Mythicomyiinae

Mythicomyia dominicana Evenhuis , sp.n.

DIAGNOSIS. Using the key to species of Nearctic species of Mythicomyia in Hall & Evenhuis (1987), this species runs to couplet 7 where it is stymied between minuta Melander 1 and bianca Tabet. It does not key to either because the scutellum in M. dominicana is entirely brown (bianca and minuta have yellow markings on the scutellum).

DESCRIPTION. Female ( Fig. 7 ). Length: 1.70 mm. Head. Vertex, occiput, and mentum black; eyes dichoptic, separated at vertex by 1.5 x distance between lateral ocelli; front and face yellowish white, tip of oral margin brown; antennae brown; scape minute; pedicel cylindrical, slightly wider than long; first flagellomere linear­lanceolate, length about 3.5 x greatest width; second flagellomere about 1/3 length of first flagellomere, with subapical sensillum; proboscis brown, thick, extending slightly beyond oral margin; palpus not evident.

Thorax. Mesonotum and scutellum dark brown, with evenly spaced short white hairs; humeral callus, post humeral area, supra alar area, and post alar callus yellow; pleura yellow above, dark brown below; coxae and basal 2/3 of femora dark brown; apical 1/3 of femora, all of tibiae, and tarsi yellow; halter stem and knob yellow.

Wing ( Fig. 7 ). Hyaline; veins yellowish brown; costa ends slightly less than halfway between end of R4+5 and M1; vein Sc complete; Rs evanescent at connection with R1; R2+3 arising at apical 1/4 of Rs, slightly sinuous to junction with R1; R4+5 straight to wing margin, not curved; vein M1 slightly curved toward wing margin; M2 fairly straight to wing margin; A1 fairly straight to wing margin, not curved or sinuous; fringe of hair on posterior margin of wing rather sparse.

Abdomen. Dorsum brown, with scattered white hairs; yellowish white laterally on tergites II–VII, sometimes extending medially as posterior fasciae, especially so on apical tergites; venter yellow. Genitalia not dissected.

TYPE. Holotype female from DOMINICAN REPUBLIC: exact locality unknown, DR­11­9, purchased from Manuel Perez, deposited in AMNH. The holotype is in a rhomboidally cut amber piece approximately 5 mm x 8 mm preserved in a clear rhomboidal cube of artificial resin measuring about 12 x 8 mm.

REMARKS. Since the unique type specimen is a female, it is impossible to ascertain subgeneric status (Mythastrabes or Mythicomyia ) without dissection to examine the spermathecae. Male specimens can be placed to subgenus by the presence ( Mythicomyia ) or absence (Mythastrabes) of male secondary sexual character modifications of the legs. Thus, this species will have to remain as “unplaced to subgenus” until associated male specimens are found.

ETYMOLOGY. The species is named for the country of its type locality on the island of Hispaniola.

Mythenteles baltica Evenhuis , sp.n.

DIAGNOSIS. Males of this species are easily distinguished from the other species known in this genus by the striking thoracic pattern including admedian yellow vittae, yellow prescutellar area, yellow scutellum, and chiefly yellow pleura (these areas dark brown in other species of Mythenteles ). The female is all brown without any contrasting pale coloration (other species in the genus have at least yellow humeral calli or post alar calli).

DESCRIPTION. Holotype female ( Fig. 8 ). Length: 0.98­1.06 mm. Head. Black; occiput and vertex black; eyes dichoptic, separated at vertex by slightly more than distance between lateral ocelli; front depressed medially, yellowish; face yellowish, tip of oral margin brown; antennae black; scape minute; pedicel cylindrical, slightly wider than long; first flagellomere ovoid, length about 2.5 x greatest width; second flagellomere about 1/3 length of first, with apical style; venter of head brown, shiny; proboscis brown, short, length about 1/2 head height; labrum sclerotised, stiff, pointed apically; palpus not evident.

Thorax. Mesonotum and scutellum shining brown; coxae and legs brown; halter stem and knob brown.

Wing ( Fig. 9 ). Hyaline; veins brown; costa just beyond vein R4+5; vein Sc incomplete, ending at level just beyond origin of Rs; Rs evanescent at connection with R1; R4+5 straight to wing margin, not curved; vein separating cells br and bm distinct; crossvein r­m at basal 1/3 of cell dm; vein M1 slightly curved toward wing margin; M2 fairly straight to wing margin; crossvein dm­cu closing discal cell present; vein A1 evanescent, present as a fold; sparse fringe of hair on posterior margin of wing rather long.

Abdomen. Terga and sterna all shining brown. Genitalia not dissected.

Male. Similar to female except as follows: the mesonotum is predominantly yellow with three longitudinal vittae as in Fig. 10 . The genitalia have the epiphallic complex elongate and extending beyond the abdomen for a length approximately 1/2 the length of the abdomen ( Fig. 11 ). The tip of the epiphallus is bifid implying that there are only two functional spermathecae in females (cf. Theodor, 1983: 29) and his remarks on an undescribed species of this genus from Israel which has a similar elongate bifid epiphallus and only two functional spermathecae.

TYPES. Holotype female from BALTIC REGION: exact locality unknown, BE-001. Currently deposited in NLE; to be deposited in MHNN (MHNN #1708). Paratypes. BAL- TIC REGION: 1 male, exact locality unknown, BE-002 (NLE); 1 male, exact locality unknown, BK-006 (OMK). The holotype is preserved in a clear polished yellowish orange amber piece approximately 15 x 8 mm without other inclusions.

REMARKS. This is the first fossil representative of the genus Mythenteles , which is known from described species occurring in Bangladesh, montane India, western China, and the SW United States; and undescribed species from Greece, Spain, Cyprus, Israel, Mexico, and California. The finding of this fossil representative gives support to the theory that this genus was once more widespread; and through time, possible glaciation events, and other calamities has been left with relictual distributions of its species.

ETYMOLOGY. The specific epithet refers to the Baltic origin of the amber harboring this species.

Figures

FIGURES 5 - 8. Habitus. 5. Glabellula brunnifrons, sp. n. (specimen DE- 001) 6. Glabellula grimaldii, sp. n. (specimen DR- 11 - 18). 7. Mythicomyia dominicana, sp. n. (specimen DR- 11 - 9). 8. Mythenteles baltica, sp. n., female habitus (specimen BE- 001).

FIGURES 9 - 11. Mythenteles baltica, sp. n. 9. wing. 10. male thorax, dorsal view (diagrammatic to show color pattern) (specimen BE- 002). 11. male postabdomen, ventral view (specimen BE- 002).