Ditylometopa centralensis, Woodley, Norman E., 2009

Woodley, Norman E., 2009, A review of the genus Ditylometopa Kertész (Diptera: Stratiomyidae), Zootaxa 2032, pp. 39-47 : 44-47

Ditylometopa centralensis sp. nov.

( Figs. 2, 4 , 6 , 12–15 )

Diagnosis. Both males and females of this species lack well defined band-like pubescent markings on the fifth tergite as found in D. elegans , but have inconspicuous, more diffuse pubescence on the lateral third of the tergite ( Fig. 6 ). Males of D. centralensis have the eighth antennal flagellomere slightly smaller and more pointed apically than that in D. elegans , and the posterior margin of the hypandrium is slightly bilobed ( Fig. 12 ) rather than evenly rounded as in D. centralensis . Females have the surface of the lower frons above the antennae less tomentose than in D. elegans , with well defined shiny areas; the margins of the lower frons and face have a narrower strip of tomentum than in D. elegans ; and the sutural area between the vertex and postocular orbits is usually not darkened, with a shallower groove just mediad of the suture.

Description. Ditylometopa centralensis is very similar to D. elegans , but differs from it as follows: Male. Head with lower frontal triangle less tomentose, lateral areas somewhat shiny. Antenna with scape and pedicel dark brownish-yellow; eighth flagellomere sharply conical at apex.

Thorax with scutellar spines black, becoming vaguely paler on apical halves. Pale vestiture of scutum slightly more silvery than in D. elegans but with same basic pattern ( Fig. 2 ). Wing slightly more yellowish, with cell r1 (“stigma”) not as strongly contrasting with rest of wing ( Fig. 2 ).

Abdomen with pale vestiture on tergites sparser and more silvery than in D. elegans , not forming as distinct a pattern as in that species; lateral pubescent spots on tergites 3 and 4 narrower; tergite 5 with lateral thirds with more diffuse pale pubescence not forming well demarcated spots ( Fig. 6 ).

Male terminalia with gonocoxites similar to those of D. elegans ( Fig.12 ); posterior margin of hypandrium slightly produced, distinctly bilobed medially; phallic complex ( Figs. 13, 15 ) slightly more robust than in D. elegans , medial lobe very slightly longer than lateral lobes; epandrium ( Fig. 14 ) not as quadrate, more ovoid, posterior margin rounded at lateral corners.

Body length, 6.1 mm.

Female. Head with frons 0.33–0.36 of head width at anterior ocellus; vertex with narrow, shallow depression on each side just mediad of upper corner of eye, this area not darkened. Lower frons with only a small medial tomentose area just above antennae, rest of surface appearing shiny with scattered hairs. Dense tomentum present on lateral margins of lower frons and face but narrower than in D. elegans .

Thorax with scutellar spines slightly shorter than in male, occasionally more yellowish. Pale pilosity of scutum slightly more silvery than that of D. elegans ; notopleural pilosity not coalescing as strongly with anterior portion of sublateral vitta, thus the vitta is more discrete anteriorly ( Fig. 4 ). Halter with knob occasionally darkened near base laterally.

Abdomen essentially as in male, with less strongly demarcated pubescent spots than in D. elegans , especially on tergite 5.

Body length, 5.9–6.9 mm.

Specimens examined. Holotype 3, COSTA RICA: Guanacaste Province, Estación Murciélago, 8 km SW of Cuajiniquil, 100m, L N 320300_347200, 22 July 1993, C. Cano (INBio). The holotype is in excellent condition. Paratypes: 1Ƥ, same data as holotype but 6–23 June 1994, F.A. Quesada (INBio); 1Ƥ, COSTA RICA: Guanacaste Province, Tilarán, Tierras Morenas, 685 m, L N 287800_427600, July 1994, G. Rodríguez (INBio; missing head and right wing); 1Ƥ, COSTA RICA: Puntarenas Province, 3 km SW of Rincon, 10 m, 8°41΄N, 83°29΄W, March–May 1991, P. Hanson, Malaise trap (USNM); 1Ƥ, NICARAGUA: Leon, June 1990, B. Garete (USNM).

Additional material, not paratype: 13, BRAZIL: Santa Catarina, Corupa (Hansa Humboldt), November 1944, A. Maller (AMNH).

Etymology. The species epithet refers to the primary range of this species, Central America.

Remarks. The male examined from Brazil is quite similar to the holotype male from Costa Rica, but differs in some minor respects. The knob of the halter of the Brazilian male is darkened laterally on the basal half (not darkened in the holotype), and all basal tarsomeres are blackish (dark yellowish on mid and hind tarsi in the holotype). In the male genitalia, the lateral lobes of the phallic complex in the Brazilian specimen are very slightly less flared laterally. However, the posterior margin of the hypandrium is slightly bilobed with a medial carina ventrally, just as in the holotype male. Two of the female paratypes from Costa Rica show evidence of darkening on the haltere, but not nearly as boldly as in the Brazilian male. It is possible that the Brazilian specimen represents a third species, but the differences are minor enough that its status cannot be determined with certainty until additional material is available for study.

Figures

FIGURES 1 – 4. Habitus images of Ditylometopa species. 1, D. elegans, male. 2, D. centralensis, male. 3, D. elegans, female. 4, D. centralensis, female.

FIGURES 5 – 7. Morphological details of Ditylometopa species. 5, D. elegans, dorsal view of female abdomen. 6, D. centralensis, dorsal view of female abdomen; note: this image makes the abdominal hairs appear denser than they actually are. 7, D. elegans, posterior view of front femur of male.

FIGURES 12 – 15. Male terminalia of Ditylometopa centralensis. 12, genital capsule, dorsal view. 13, phallic complex, dorsal view. 14, epandrium and post-genital segments, dorsal view. 15, phallic complex, left lateral view.