Beardius chapala, Pinho & Mendes & Andersen, 2013

Pinho, Luiz Carlos, Mendes, Humberto Fonseca & Andersen, Trond, 2013, Revision of Beardius Reiss et Sublette, 1985 (Diptera: Chironomidae), with the description of twenty new species, Zootaxa 3742 (1), pp. 1-78 : 28-29

Beardius chapala sp. n.

( Figs 35–36 )

Type material. Holotype male, MEXICO, Jalisco State: Lake Chapala, El Chante , 26.xi.1981, MF1, H.W. Fittkau ( ZSM).

Diagnostic characters. The species belongs in the truncatus group. The male can be separated from all other members of the genus by the combination of the following characters: acrostichals present; median volsella absent; and basal projection of the inferior volsella long, digitiform.

Etymology. The name refers to the type locality, Lake Chapala. The name is to be regarded as a noun in apposition.

Description

Male (n = 1). Total length 2.75 mm.

Coloration. All pale.

Head and wings. Lost.

Thorax. Scutal tubercle absent. Antepronotum without setae. Dorsocentrals 8, acrostichals 4, prealars 2. Scutellum with 6 setae.

Legs. Fore leg, mid and hind tarsi lost. Spur of mid tibia (including comb) 36 µm long, spur of hind tibia (including comb) 40 µm long. Width at apex of mid tibia 48 µm, of hind tibia 52 µm. Lengths and proportions of legs as in Table 6.

Hypopygium ( Figs 35–36 ). Anal point absent. Tergite IX without setae, tergal bands absent. Laterosternite IX with 2 setae. Phallapodeme 75 µm long. Transverse sternapodeme 67 µm long. Gonocoxite 152 µm long. Superior volsella digitiform, 93 µm long, with 7 dorsal, 2 apical, and 1 ventral setae, without microtrichia. Median volsella absent. Inferior volsella slightly clavate, 132 µm long, with 2 apical thin and 4 short, stout, subapical setae; projection arising from base of volsella, digitiform, curved, with narrow base, 91 µm long, densely covered with long microtrichia. Gonostylus not measurable.

Female and immatures. Unknown.

Distribution. The species is collected in the Jalisco State in Mexico.

Figures

FIGURES 35–36. Beardius chapala sp. n., male. 35—tergite IX and dorsal aspect of left gonocoxite and gonostylus; 36— hypopygium with tergite IX removed, left dorsal aspect, right ventral aspect.