Alipumilio athesphatus, Morales, Mírian Nunes, Massardo, Darli, Moreira, Gilson R. P. & Thompson, Christian, 2009

Morales, Mírian Nunes, Massardo, Darli, Moreira, Gilson R. P. & Thompson, Christian, 2009, A new species of Alipumilio Shannon (Diptera, Syrphidae) found in association with the exudate resin of Schinus terebinthifolius Raddi (Anacardiaceae), Zootaxa 2112, pp. 53-64 : 55-62

Alipumilio athesphatus sp. n. Thompson

Alipumilio species 1. Thompson 1972: 127 (male genitalia).

Description. Egg ( Figs 1–4 ). Length 1.2–1.26 mm (n = 8), maximum width 0.61 mm. White in color throughout the embryonic development. Elongated-oval in shape, rounded at both ends and slightly tapering towards the anterior pole, and laid with the micropylar axis parallel to the substrate ( Fig. 1 ). The micropyle appears as a conspicuous black crown-like on the anterior pole ( Fig. 2 ). The chorionic surface sculpturing is delicate: a plastron meshwork ( Hinton 1981) composed of longitudinally ridged cuneiform projections ( Figs 3–4 ).

Alipumilio athesphatus eggs are laid isolated into small bark crevices of S. terebinthifolius stems. Additional laboratory observation showed that soon after hatching, the larva digs a small hole and buries itself into the plant tissues below. Remains of the chorion is frequently found attached to resin exudate on S. terebinthifolius plants.

Third instar larva ( Figs 5–19 ). Shape and dimensions. Length 8–16 mm (n = 10); maximum width 3mm; larva pale in color; cylindrical in cross-section, truncate anteriorly and tapering posteriorly ( Fig. 5 ). Dorsal body surface coated in fine and sub-developed pubescence, patchily distributed. Anterior fold with longitudinal bands of short spicules. Sensilla accompanied by two or more setae; pattern of sensilla similar to other Syrphidae ( Rotheray & Gilbert 1999) .

Prothorax. Ventroanterior region. Antennomaxillary complex well developed ( Figs 10, 13 ). Dorsal lip smooth, lacking setae medially ( Figs 10, 11 ). Lateral lips little developed and covered with conspicuous setae. Cephalo-pharyngeal skeleton with a huge, black and heavily sclerotized pair of mandibular hooks ( Figs 5, 6 , 10, 11 ); mandibular lobes are fused on mandibular apodeme ( Fig. 6 ). Lateroanterior region. Anterior spiracles sclerotized and strongly reduced ( Figs 12, 14 ). Dorsal region. Surface with a triangular heavily sclerotized plate, without spicules, bearing sensilla 1–3 ( Fig. 12 ).

Mesothorax. Dorsal surface with a less sclerotised region than dorsal surface of prothorax, without spicules ( Fig. 12 ).

Abdomen. Prolegs on segments 1–7 with bearing sparse distributed crochets and lacking a planta ( Fig. 5 a). Lateral region of abdominal segments 1–8 with two pseudopodium, vertically distributed, coated by delicate setae. Dorsal surface of first segment with two tubercle of differentiated cuticle forming the opening through which the pupal spiracle will be thrust ( Fig. 5 , 15 , 20 ). Lappets on eighth segment have one sensillum at the tip, a second lower down and a third bifurcated towards the base ( Fig. 16 ). Posterior respiratory process dark-brown, lustrous, heavily sclerotized, bifurcated and retractile ( Figs 5, 7 –9,17); each apical tip bearing longitudinal spiracular openings ( Fig. 19 ), with four spiracular groups of setae, one anterior, one posterior and two lateroexternal ( Fig. 18, 19 ); base of the bifurcation, from the second and third larval instars, bearing two outer scars of the preceding spiracles ( Fig. 17 ).

Instar identification. Alipumilio athesphatus larvae pass through three larval instars, which can be identified by differences existing in the size of their respiratory processes. In the first instar, the base of the respiratory process is shorter than the arms, and to the contrary in the last (= third) instar, where the base is much greater in length. These portions of the respiratory process are similar in length in the intermediate (= second) instar ( Figs 7–9 ).

Data resulting from measurement of the total length of the respiratory process for the different larval instars significantly adjusted to the equation ln y = 0.548x – 2.192; r = 0,978; n = 30; p <0,0 0 1. There was no overlap on such values among instars (Table 1), and thus they can also be identified by measuring that structure. The respiratory process grew geometrically at an average rate of 1.73 among instars, thus following the Brooks-Dyar rule found for several insects ( Daly 1985).

Pupa ( Figs 20–24 ). Cylindrical in cross section. Anterior end truncate, tapered posteriorly ( Figs 20, 21 ). Pupal spiracles. Dark brown in color; projecting from middle of upper part of operculum, separated by distance similar to the length of one spiracle ( Figs 21–24 ). These processes are horn-like structures, approximately 1.2mm in length and tapering with spiracular openings clustered at lateral edges ( Figs 23 , 24 ). Each tubercle has from 4 to 5 oval openings ( Fig. 24 a). Entire surface smooth, except lightly reticulated in region which is internal in the tegument.

TABLE I. Arithmetic Mean (+ Standard Error) and interval of variation (IV) for the size of the respiratory process

among larval instars of Alipumilio athesphatus sp. n. Thompson reared on Schinus terebinthifolius . N = 30 (10 larvae per

instar).

Length (mm)

Adult ( Figs 25–32 ). Male. Length: body, 6.5–7.4 mm; wing, 5.1–6.3 mm (n = 10) ( Figs 25, 26 ). Head. Black; face and gena white pilose, narrowly white pollinose ventrad to antenna, punctate on ventrolateral 1/3; frontal triangle punctate, golden pilose; vertical triangle golden pilose ( Fig. 27 ); occiput yellow pilose; antenna brownish orange to black, yellow and black pilose; arista black; eye yellow and brown pilose, with brown pile narrowly along anterior edge, broadly on area of enlarged ommatidia on anterodorsal 1/2 and broadly extending to posterior edge dorsally Thorax. Black; scutum punctate, short black pilose except with yellow pilose vittae, with medial, submedial and lateral pilose vittae; scutellum black pilose except for yellow submedial pilose vitta continuous from scutum to apex of scutellum; katepisternum punctate, yellow pilose; plumula black; calypter white; halter brown. Legs. Black except metafemur dark reddish brown in holotype; coxae, trochanters and femora yellow pilose; tibiae reddish-brown pilose; tarsi reddish-brown pilose dorsally, yellow pilose ventrally. Wing. Brownish, with stigma brown, entirely microtrichose. Abdomen. Black except sterna reddish brown; first tergum short black pilose except yellow apicolaterally; second tergum yellow pilose apicolaterally and medially on basal 1/3, short black pilose elsewhere; third tergum similar to second but also with yellow pilose apicomedially; fourth tergum yellow pilose; sterna yellow pilose. Genitalia. Sparsely grayish pollinose, yellow pilose. Cercus trapezoidal in lateral view ( Fig. 29 ). Surstylus broad, with a medial indentation in lateral view ( Fig. 29 ). Hypandrium dilated, ctenidion absent ( Fig. 30 ).

Female. Similar to the male, except for normal sexual dimorphism and: dichoptic ( Fig. 28 ); frons white pilose and pollinose ( Fig. 28 ); wing hyaline. Genitalia. Three spermathecae drop-like in shape ( Fig. 31 ). Tergum VIII slightly sclerotinized ( Fig. 32 ).

Variation: The specimens from Bolivia are much darker, black instead of brownish black; their antennae are entirely black, whereas the type and other Argentinean specimen have the basoflagellomere orange. As the male genitalia are the same in the Argentinean and Bolivian specimens, we have not recognized this color difference as significant.

Remarks. Alipumilio athesphatus is easily recognized as it is the only species in the genus with a dark halter. Also, the alternating vittae of pale and dark pile on the scutum is distinctive.

Type Material. Holotype (Male). ARGENTINA. Entre Rios: Pronunciamento, December 1966, F. Walz, from the personal collection of F. C. Thompson, to be deposited in USNM, Washington.

Paratypes (11): ARGENTINA. Cordoba: Dean Funes, 24 km S of, 8 February 1951, Ross & Michelbacher (1 male, CAS). BOLIVIA. Cochabamba: Cochabamba, 17o23’3”S 66o07’N, 2610 m, 25 March 2001, A. Freidberg (5 males, 3 females CBFC, USNM). BRAZIL. Rio Grande do Sul: Porto Alegre, Parque Natural Morro do Osso, 18.xii.2007, D. Massardo reared from Schinus terebinthinfolius stems (1 male, 2 females, DZUP). Santa Catarina: Imbituba, 14 km north of, 27.00620°S 48.58206°W, 10 July 2008, Wheeler & McKay, reared from Schinus terebinthinfolius stems (1 male, 1 female, USNM).

Additional examined material. BRAZIL. Rio Grande do Sul. Porto Alegre, UFRGS-Campus do Vale, D. Massardo, 7.xii.2007 (8 larvae, DZUP); 18.xii.2007 (4 larvae, DZUP); i.2008 (16 larvae, DZUP); 14.i.2008 (female, DZUP). Parque Natural Morro do Osso, D. Massardo, 27.xi.2008 (27 larvae, DZRS); 18.xii.2007 (4 males and 2 females, DZUP); xii.2007 (2 males and 2 females, DZUP).

Distribution: Brazil, Bolivia and Argentina.

Derivation of specific epithet: The epithet is derived from the Greek, athesphatos, meaning inexpressible or marvelously great ( Brown 1956: 110) and is used as an adjective.

Figures

FIGURE 24. Alipumilio athesphatus sp. n., pupal spiracle: (a) detail of circular-shaped tubercle, with five spiracular openings (which are covered by resin). Scale bar: 100 µm.

FIGURES 1 – 4. Alipumilio athesphatus sp. n., egg (SEM). (1) Laterodorsal view. (2) Detail of micropyle. (3 – 4) Detail of chorionic surface. Scale bar: Fig. (1): 200 µm; Figs (2 – 3): 20 µm; Fig. (4): 10 µm.

FIGURES 5 – 9. Alipumilio athesphatus sp. n., immature stages. Third instar larvae: (5) lateral view: (a) detail of proleg. (6) Mandible, lateral view. Posterior respiratory process: (7) First instar larvae. (8) Second instar larvae. (9) Third instar larvae. Scale bar: Fig. (5): 1 mm; Fig. (6): 0.5 mm; Figs (7 – 9): 0.25 mm. (mal) mandibular apodeme fused to mandibular lobe. (mdh) mandibular hook. (ple) proleg. (tar) tentorial arm. (tdc) tubercle of differentiated cuticle.

FIGURES 10 – 15. Alipumilio athesphatus sp. n., third instar larvae (SEM). (10) Prothorax, anteroventral view. (11) Mandibular hook, anterior view. (12) Prothorax, dorsal view (anterior spiracle released with a square). (13) Antennomaxillary complex, anterodorsal view. (14) Anterior spiracle, anterodorsal view. (15) Tubercle of differentiated cuticle, first abdominal segment, anterior view. Scale bar: Figs (10, 11, 15): 100 µm; Fig. (12): 200 µm; Fig. (13): 20 µm; Fig. (14): 10 µm. (ant) antenna. (atc) antennomaxillary complex. (mdh) mandibular hook. (mxp) maxillary palp.

FIGURES 16 – 19. Alipumilio athesphatus sp. n., posterior respiratory process, third instar larvae. (16) Anterobasal view. (17) Anterior view. (18 – 19) Apical tip. Scale bar: Fig. (16): 100 µm; Fig. (17): 200 µm; Fig. (18): 50 µm; Fig. (19): 10 µm. (lap) lappet. (sop) spiracular opening. (ssc) spiracular scar.

FIGURES 20 – 23. Alipumilio athesphatus sp. n., pupae. (20) Pupa, initial stage of development. (21) Pupa into a drop of exudate resin. (22) Pupa, final stage of development (note the adult emerging). (23) Detail of pupal spiracle. Scale bar: Figs (20 – 22): 1 mm; Fig. (23): 0.25 mm. (psc) pupal spiracle. (tdc) tubercle of differentiated cuticle.

FIGURES 25 – 28. Alipumilio athesphatus sp. n., adult. Male: (25) Dorsal view. (26) Lateral view. (27) Head, anterior view. Female: (28) Head, anterior view. Scale bar: 1 mm.

FIGURES 29 – 30. Alipumilio athesphatus sp. n., male genitalia. (29) Epandrium, cercus and surstylus, lateral view. (30) Hypandrium and associated structures, lateral view. Scale bar: 0.25 mm.

FIGURES 31 – 33. Alipumilio athesphatus sp. n., female genitalia. (31) Dorsal view. (32) Spermatheca. (33) Detail of epiproct and cercus. Scale bar: Fig. (31): 0.25 mm. Figs (32 – 33): 0.15 mm. (cer) cercus. (ept) epiproct. (viii) = tergum VIII.