Eosalpingogaster umbra Mengual and Thompson, 2011

Pérez-Bañón, Celeste, Arcaya, Evelin, Mengual, Ximo & Rojo, Santos, 2013, Preimaginal morphology of the genera Salpingogaster Schiner, 1868 and Eosalpingogaster Hull, 1949 (Diptera: Syrphidae), with its systematic implications, Zootaxa 3599 (4), pp. 361-370 : 363-364

Eosalpingogaster umbra Mengual and Thompson, 2011

Comparing the morphology and ultrastructure of the posterior breathing tube (prp = posterior respiratory process) of the available puparia from type material showed unexpectedly that there were two different morphotypes. Three specimens were studied: two males, showing one puparial morphotype, and one female with a completely different morphotype. We consider that the true puparial morphotype of Eosalpingogaster umbra is the one associated to the studied male specimens, as one of the males is not totally emerged from the puparium. We also think that the puparium associated to the female individual of E. umbra does not belong to this species, and it may be the result of erroneous taxonomy or human error. Therefore, this puparium is here described as Eosalpingogaster sp. because its identity is unclear. See a more comprehensive discussion below about the improbability of immature sexual dimorphism in this species.

Overall appearance. Length 5–6 mm, maximum width 2.5 mm and height 2.5 mm. Pear-shaped, in profile with dorsal and ventral margins of the posterior end forming an acute angle until the anterior bulge (fourth first abdominal segments); see Fig. 1C, D. Outline serrated, sub-cylindrical in cross-section, anterior end truncate, tapered posteriorly and flattened ventrally. Integumental vestiture and segmental sensilla persisting except on the ventral surface. Dorsal surface covered with minute blunt-tipped papillae. Colour of empty puparium cream with bright brown spots on most basal papillae of segmental sensilla; a slightly dark brown spot in front of the tubercles of segmental pair of sensilla 1 on 3rd abdominal segment. The serrated outline is due to great development of basal papillae of segmental sensilla as tubercles on the 2nd, 3rd and 4th abdominal segment (Fig. 2A). There are three transverse rows of paired tubercles (segmental pairs of sensilla 1, 2, 3 and 5–6). Tubercles of segmental pair of sensilla 1 are less developed on the 2nd than on the 3rd and 4th abdominal segment. Tubercles of segmental sensilla 5–6 (born on the same papilla) are clearly smaller than the others tubercles on the three abdominal segments. On the last abdominal segments (5th, 6th and 7th) the basal papillae of segmental sensilla are dried and collapsed not forming tubercles. Dorsal and dorsolateral segmental pairs of sensilla with apical setae not visible. The last three abdominal segment (5th, 6th and 7th) and anal segment narrowed significantly towards the base of posterior breathing tube.

Posterior breathing tube (prp): Short, broader than long. Dark brown in colour, lustrous. Spiracular plate little higher than wide, not differentiated in colour from the rest of prp. Spiracular plate divided by a shallow Vshape median groove. Ecdysial scars displaced anteriorly. Diameter of ecdysial scars is almost the length of the spiracular opening I. Dorsal spur absent (compare with Fig. 3 B-D). Spiracular openings straight, mounted on welldeveloped carinae. Carinae about twice as long as wide, extending down the sides of prp. Spiracular opening II closer to III than to I. Spiracular openings II and III parallel, inserted almost at the same level ( Fig. 3 A). Interspiracular ornamentation reduced, interspiracular setae very short, hardly visible by light microscope, mounted inside of small circular nodules, periorificial setae between openings I and II close, with their nodules almost connected.

Material examined: VENEZUELA: 1 3 puparium+adult, Distrito Federal, cumbre de Boquerón frente a Bajo Seco, 1700 m., 7.iii.1970, leg. F. Fernández & C.J. Rosales, “ex. Larva predadora de Coccus viridis sobre naranjo” USNM ENT 00037123 ( MIZA); 1 3 puparium+adult (imago inside not totally emerged), Falcón, El Supi, 29.xii.1971, leg. V. Vargas, “ex. larva pred. Aspidiotus destructor en Cocos nucifera ” USNM ENT 00036800 ( USNM).

FIGURE 1. Dorsal and lateral view of puparium. A, B, Salpingogaster nigra ; C, D, Eosalpingogaster umbra ; E, F, Eosalpingogaster sp. Arrows point to the transverse rows of segmental tubercles on 2nd, 3rd and 4th abdominal segment.

Figures

FIGURE 3. Posterior respiratory process (prp). A, Eosalpingogaster umbra; B, Salpingogaster nigra; C, Eosalpingogaster sp.; D, Ocyptamus sp.; E, Toxomerus sp. Arrows point to spiracular openings.