Diplosmittia trifida, Shimabukuro & Lamas & Pinho, 2020

Shimabukuro, Erika Mayumi, Lamas, Carlos José Einicker & Pinho, Luiz Carlos, 2020, Brazilian Diplosmittia Saether: D. trifida sp. n. and new records of D. plaumanni Pinho, Mendes & Andersen, 2009 (Diptera: Chironomidae), Zootaxa 4885 (1), pp. 139-142 : 139-141

Diplosmittia trifida sp. n.

Zoobank: 7DB33016-19D6-41F1-8912-74CB2F45ED43

Type material. Holotype male, BRAZIL, Amazonas State , PARNA Pico da Neblina, Laje Stream, #17_M1600, 00°46’03”N 66°00’25”W, 1609 m a.s.l., 18.vii.2019, Malaise trap, EM Shimabukuro ( MZUSP).

Diagnosis. Diplosmittia trifida sp. n. is the only species in the genus with gonostylus split into three branches.

Etymology. The specific epithet is a Latin adjective ( trifida meaning divided into three or consisting of three parts), referring to the gonostylus being split into three parts.

Description. Male (n = 1). Total length 1.50 mm. Wing length 0.86 mm. Total length/wing length 1.74. Coloration brownish; thorax with scutum, postnotum, median anepisternum, and preepisternum dark brown; tarsi light brown. Microtrichia arranged in patches in some areas on the head, thorax and abdomen (as in tergite IX, Fig. 1B ).

Head. Antennae lost. Postorbitals 2, outer verticals 4, without inner verticals. Clypeus with 4 setae. Tentorium 77 μm long, 10 μm wide; stipes 72 μm long. Palp lost.

Thorax. Antepronotum with 1 seta. Dorsocentrals 5, acrostichals 2 in median field, prealars 2. Scutellum with 4 setae.

Wing ( Figure 1A ). VR 1.53. R 2+3 ending closer to R 4+5 than to R 1. Costal extension 108 μm long, weak false vein reaching tip of wing. Brachiolum with 1 seta.

Legs. Anterior and mid legs lost. Hind femur 309 μm long; hind tibia 358 μm long; tarsomere lengths (in μm): 152, 88, 88, 29, 34. Spurs of hind tibia 27 and 12 μm long. Width at apex of hind tibia 10 μm.

Hypopygium ( Figure 1 B–E). Anal point not crested ( Figure 1B ), 10 μm long, 25 μm wide at base, 7 μm wide at apex, with 6 strong setae. Laterosternite IX with 3 setae. Phallapodeme 80 μm long. Transverse sternapodeme 40 μm long. Virga 62 μm long ( Figure 1C ). Gonocoxite 75 μm long, without volsellae ( Figure 1 B–C). Gonostylus with three lobes ( Figure 2 D–E); main lobe 39 μm long, ventromedially projecting lobe 57 μm long, dorsocaudally projecting lobe 30 μm long; megaseta 12 μm long. HR 1.92; HV 3.84.

Female and immatures. Unknown.

Distribution ( Figure 1 ). Diplosmittia trifida sp. n. is only known from the type locality, Neblina Peak, Northwestern Brazil, where it was collected in a Malaise trap placed close to a low order stream at 1600 m a.s.l. Only a single male was collected despite intensive sampling effort during the expedition with successive sampling with light traps, emergence traps and Malaise traps from 100 m up to 2800 m a.s.l.

Remarks. The new species belongs to Diplosmittia due to the combination of the following diagnostic characters established by Pinho et al. (2009): two short acrostichals in midscutum, absence of volsellae, and presence of a deeply divided gonostylus. Also, the strongly sinuous Cu 1 of D. trifida sp. n. is present in most Diplosmittia species. The third lobe of the gonostylus, i.e., the dorsocaudally directed lobe seems to be derived from the base of the dorsal surface of the main lobe of gonostylus. The new species shares some similarities with D. plaumanni , such as the well-developed costal extension, patches of microtrichia in some parts of body, an anal point without crest, projected beyond the posterior margin of tergite IX and the presence of a long virga with bulbous base.

Figures

FIGURE 1. A–E. Diplosmittia trifida sp. n., male adult. A, wing. B, anal point and tergite IX and dorsal aspect of left gonocoxite and gonostylus. C, hypopygium with anal point and tergite IX removed, left dorsal aspect, right ventral aspect. D, gonostylus, dorsal aspect. E. gonostylus, ventral aspect.

FIGURE 2. Distribution map of D. plaumanni Pinho, Mendes & Andersen and D. trifida sp. n.