Atrichopogon (Meloehelea) chilensis Ingram & Macfie, 1931

Tóthová, Andrea, Spinelli, Gustavo R. & Marino, Pablo I., 2009, A new Nearctic species of Atrichopogon (Meleohelea) and a redescription of Atrichopogon (M.) chilensis Ingram & Macfie (Diptera: Ceratopogonidae), Zootaxa 2023, pp. 47-54 : 48-50

Atrichopogon (Meloehelea) chilensis Ingram & Macfie, 1931

Atrichopogon (Kempia) chilensis Ingram & Macfie, 1931: 175 (female; Argentina, Chile).

Atrichopogon chilensis: Wirth, 1974: 13 (in Catalog of south USA; distrib., Brazil record erroneuos).

Atrichopogon (Meloehelea) obnubilus: Spinelli & Wirth, 1992: 94 (synonymy); Spinelli & Wirth, 1993: 24 (in list; Argentina); Borkent & Wirth, 1997: 26 (in World Catalog); Borkent & Spinelli, 2000: 11 (in Catalog, southern USA); Spinelli et al., 2006: 314 (diagnosis; distrib.); Borkent & Spinelli, 2007: 46 (in Neotropical Catalog).

Diagnosis: Male adult: only extant species of Atrichopogon (Meloehelea) in the Neotropical region with posterodorsal projection of aedeagal-parameral complex tapering to cap-like process and the lateral margins of posteroventral process sinuate, its posteromedial portion notched. Female adult: not distinguishable from those of A. oedemerarum .

Description: Male adult: Descriptive measurements in Table 1. Head: Ommatidia without interfacet pubescence ( Fig. 1 D). Antenna light brown; with plume well developed; with 13 flagellomeres, proportions as shown in Fig. 1 B; flagellomeres separate; flagellomere 13 with apical projection not constricted basally. Maxillary palpus light brown ( Fig. 1 B); third segment moderately long, with well-developed pit located at midlength; segments 4, 5 separate. Thorax ( Fig. 1 A) dark brown; scutum with setae arising directly from surface; paratergite with 1 seta. Anepisternum well developed, sharply bilobed posteriorly. Wing ( Fig. 1 E) without pattern of pigmented membrane, with macrotrichia at the apex of r3 and m1. Halter: white. Legs: Light brown; empodia present. Abdomen ( Fig. 1 A): medium brown. Genitalia ( Fig. 1 C): Of moderate size, segment 9 about equal in width to segment 8, tergite 9 short, not extending to apex of gonocoxite; posterior margin rounded. Sternite 9 with posterior margin concave, with scattered setae. Gonocoxite without medial lobe. Gonostylus tapering from base, gently curved, apex pointed. Aedeagal-parameral complex broad; posterodorsal projection tapering to cap-like process; lateral margins of posteroventral process sinuate, posteromedial portion notched; gonocoxite length/ width 2.00–2.14. Cercus short, lobe-like, ventral to tergite 9.

A. (M.) chilensis A. (M.) ladislavi MALE FEMALE FEMALE n=5 n=11 n=2

Wing length (mm) 1.42–1.72 1.60–2.04 1.1

Costal ratio 0.63–0.65 0.71–0.75 0.70–0.71 Head width/mouthpart length 1.9–2.2 1.50–2.0 1.0–1.1 Antennal ratio 1.02–1.10 1.81–2.27 1.96–2.06 Tarsal ratio 2.46–2.72 2.35–2.69 2.20–2.45 Palpal ratio 3.11–3.50 2.75–3.08 4.76–4.89 Flagellomeres 9/10 0.61–0.69 - -

Gonocoxite length/width 2.00–2.14 - -

Length of spermatheca (μm) - 86.47–115.9 68.40–86.72 Female adult: As for male, with following differences. Descriptive measurements in Table 1. Head: Antenna medium brown, with 13 flagellomeres, flagellomeres 1–8 moniliform, proportions as shown in Fig. 2 E. Mandible well developed, with 26–33 small, fine teeth ( Fig. 2 D). Laciniae with pale indistinct teeth, elongate spicules. Palpus ( Fig. 2 B) moderately elongate, pit at midlength. Thorax: scutum brown, with faint, narrow, pale lateral stripes from pale humeral areas, scutellum pale brown ( Fig. 2 A). Wing ( Fig. 2 F) without pattern of pigmented membrane, with macrotrichia on entire membrane, not below basal radial cell, macrotrichia very abundant in r3 and m1, 30– 35 in m2, 10– 15 in cua1, and 22–35 in anal cell. Abdomen ( Fig. 2 C): light brown. Genitalia: Two equal ovoid spermathaecae, each with moderately elongated neck.

Distribution and bionomics: Atrichopogon chilensis inhabits Nothofagus forests within the Valdivian forests of Chile and Argentina. The dominant species in these forests are N. dombeyi (“coihue”), N. pumilio (“lenga”) and N. antarctica (“ñire”), from sea level to an elevation of 791 m. Most specimens were collected in the Valdivian rain forests, a very humid environment with an annual rainfall of 2000 to 4000 mm, which possesses a very rich biota.

Taxonomic discussion and notes on types: On the basis of the variability of characters used by Ingram & Macfie (1931) to distinguish the Patagonian species A. assimilis , A. chilensis and A. obnubilus, Spinelli & Wirth (1992) proposed that A. assimilis and A. chilensis be considered as junior synonyms of A. obnubilus . A recent reexamination of the slide-mounted types of A. assimilis , A. chilensis and A. obnubilus revealed that A. chilensis , a species only represented by female specimens in the type-series, has pale humeral areas (scutum uniformly dark brown in the male holotype and female paratype of A. obnubilus ) and possesses 29 macrotrichia in the anal cell and 15 in cua1 (2 and 3, respectively, in the female paratype of A. obnubilus ). Moreover, the collections by J.A. Downes in the 1980s in Chile and the specimens recently obtained in Argentina, provided specimens that perfectly match with the female paratype of A. chilensis that was collected and associated with males showing differences when compared to the male holotype of A. obnubilus . The male wing of A. obnubilus is lacking macrotrichia, and its male genitalia are easily distinguished from those of A. chilensis by the rounded posteroventral margin of the aedeagal-parameral complex.

The genitalia of the male holotype of A. assimilis are not in position to be examined, and it is almost impossible to observe the features of the aedeagal-parameral complex. Because of this, and the fact that the extragenital characters are very similar to those of A. obnubilus , the species must remain under synonymy. The male of A. oedemerarum shares with A. chilensis the presence of macrotrichia in r3 and m1, but differs in the triangular posterodorsal projection of the aedeagal-parameral complex (tapering to cap-like process in A. chilensis ).

Specimens examined: Argentina, Bariloche, 1.xii.1926, F. & M. Edwards (female holotype, BMNH); Parque Nacional Nahuel Huapi, Puerto Blest, Estación Biológica, 41º01’34.4”S 71º48’55.7”W, 791 m, 13/ 16.xii.2006, A. Garré – F. Montes de Oca, 2 females, 1 male, light trap; Parque Nacional Nahuel Huapi, Mallín La Cortadera, 41º05’13”S 71º48’26”W, 769 m, 8.i/ 3.ii.2007, A. Garré – F. Montes de Oca, 1 female, Malaise trap; Parque Nacional Nahuel Huapi, La Cantera, 41º21’16”S 71º42’27.3”W, 764 m, 11/ 30.xii.2006, A. Garré – F. Montes de Oca, 3 males, Malaise trap; same data except 15.i/ 7.ii.2007, 1 female (MLP).

Chile, Cautín Prov., Lago Conguillio, 6. xii. 1984, J. A. Downes, 1 female (1661/8/3), 7.xii. 1984, J. A. Downes, 1 female (1662/1/5), 16.xii. 1984, J. A. Downes, 1 female (1670/3/8), 22.xii.1984, J. A. Downes, 2 females (1677/1/4, 1677/1/8), 1 male (1677/1/6), 1.i. 1985, J. A. Downes, 1 female (1688/1/2), 12.–14.i. 1985, J. A. Downes, 1 female (1696/5/23), (CNCI).

Figures

FIGURE 1. Male of Atrichopogon (Meloehelea) chilensis Ingram & Macfie. A—thorax (lateral view), B-head (dorsal view), C—hypopygium (ventral view), D—compound eye (dorsal view), E—wing

FIGURE 2. Female of Atrichopogon (Meloehelea) chilensis Ingram & Macfie. A—thorax (lateral view), B—head (dorsal view), C—terminal abdominal segments and spermathecae (ventral view), D—mouthparts (dorsal view), E—antenna, F—wing