Thaumastaneis nigricans, Dellapé, Pablo Matías & Melo, María Cecilia, 2007

Dellapé, Pablo Matías & Melo, María Cecilia, 2007, Thaumastaneis nigricans, a new species of a remarkable ant-mimetic Larginae (Hemiptera: Largidae) and the discovery of an ant-mimetic complex, Zootaxa 1475, pp. 21-26 : 22-24

Thaumastaneis nigricans n. sp.

( Figs 1–6)

Material examined. Holotype: male, BOLIVIA: Trinidad, X-1917, 50276, Thaumastaneis montandoni Kirkaldy & Edwards , det. N. Kormilev ( MACN).

Paratype: female, BOLIVIA: Santiago, Chiquitos, Santa Cruz, 8/ 13-II-1958, Monrós col., Thaumastaneis sp. det. M. V. Ahmat 1982 ( IML).

Diagnosis. General color black except tibiae and tarsi slightly paler, and antennae reddish brown. Hemelytra with apex rounded. Parameres with an oblique ridge near apex well developed forming an acute tubercle.

Description. Male ( Fig. 1): General color black. Total length 10.26. Head strongly globose with black and white long erect setae, adpressed silver setae and a triangular patch of black semidecumbent setae between eyes. Head length 2.43 [in lateral view, a tangential line to inferior margin of eye from vertex to apex of tylus], postocular length 1.70, width 2.30, width before eyes 1.70, interocular space 1.54. Antennae reddish brown, distiflagellomere paler; scapus with erect setae, rest of antennae with very short semidecumbent setae. Antennal length: scapus 2.02, pedicellus 0.90, basiflagellomere 0.51, distiflagellomere 2.21. Eyes small, protruberant. Rostrum shorter than head including neck; with erect setae ventrally. Rostrum length: article I 0.54, II 0.61, III 0.70, IV 0.42. Neck long; dorsal surface with minute pitted texture.

Thorax: Pronotal collar with adpressed silver setae; anterior lobe globose, shiny, with long erect setae; posterior lobe short, with long erect setae and adpressed silver setae, pruinose medially, humeral angles with a long stout spine slightly curved at apex and with a few long erect setae. Pronotal length 1.66, width 1.28. Scutellum with large conical tubercle at base, with sparse long erect setae and adpressed silver setae. Scutellar length 1.02, width 0.48. Hemelytra with adpressed silver setae, apex rounded slightly surpassing abdominal segment II. Hemelytral length 1.86. Pleura and sterna shiny, with adpressed setae and sparse long erect setae. Metepimeron swollen. Legs: Coxae with adpressed silver setae, procoxae with a tubercle. Femora with long erect setae; profemur with two subapical spines, apicalmost smaller; metafemur longer, with long plectrum over basal half. Tibiae slightly paler with long erect setae and spiniform setae apically. Tarsi slightly paler with semidecumbent setae and spiniform setae on tarsomere I. First tarsomere two times longer than II + III, tarsomere II shortest.

Abdomen constricted at base and swollen at middle. Laterotergites with adpressed silver setae, tergites shiny with sparse long erect setae, sternites shiny with long erect setae and patches of adpressed short silver setae. Margins of segments II to IV finely rugose. Three abdominal scent gland openings on segments III/IV, IV/V and V/VI. Male genitalia ( Figs. 2–6 ): Pygophore, dorsal aperture as fig. 2. Paramere ( Figs. 3–4 ) with oblique ridge near apex well developed forming an acute tubercle ( Fig. 4 ). Spur perpendicular to shaft. Aedeagus ( Figs. 5–6 ) with ejaculatory reservoir rounded, wings curved backward and conjunctiva with subquadrangular sclerotized posterior lobe.

Female. Similar to male in all respects except with less globose anterior pronotal lobe, less developed and less curved humeral spines, less prominent scutellar tubercle, less punctate hemelytra and posterior pronotal lobe, and with adpressed setae on abdominal tergites.

Measurements: Total length 12.66. Head length 3.04, postocular length 1.98, width 2.78, width before eyes 2.18, interocular space 1.79. Antennal length: scapus 2.69, pedicellus 1.28, basiflagellomere 0.74, distiflagellomere 2.27. Rostrum length: article I 0.86, II 0.77, III 0.80, IV 0.54. Pronotal length 1.63, width 1.66. Scutellar length 0.99, width 0.61. Hemelytral length 1.89.

Etymology. The name refers to the blackish coloration of this new species.

Discussion. In addition to the characters mentioned in the diagnosis, T. nigricans can be distinguished from T. montandoni by its more elongate head, males with humeral spines more elongate and with fewer setae, posterior pronotal lobe without punctures or these less conspicuous than in T. montandoni , absence of adpressed setae on anterior pronotal lobe, and setae on legs of equal length. The male genitalia of the species ( Figs. 2–11 ) have more differences. The parameres of T. montandoni ( Figs. 8–9 ) have a less developed tubercle and the spur is shorter and more curved than in T. nigricans . The aedeagi are quite similar, but in T. montandoni the sclerotized posterior lobe of the conjunctiva is more rounded ( Figs. 10–11 ).

Figures

FIGURES 2 – 11. Thaumastaneis sp., male genitalia. (2 – 6) Thaumastaneis montandoni Kirkaldy & Edwards. (2) pygophore, dorsal view; (3) right paramere, outer view; (4) right paramere, inner view; (5) aedeagus, anterior view; (6) aedeagus, lateral view; (7 – 11) Thaumastaneis nigricans n. sp. (7) pygophore, dorsal view; (8) right paramere, outer view; (9) right paramere, inner view; (10) aedeagus, anterior view; (11) aedeagus, lateral view.