Belostoma nieseri Ribeiro & Ferrari, 2023

Ribeiro, Jose R. I. & Ferrari, Augusto, 2023, Phylogenetic analysis of the Belostoma plebejum group sensu Nieser (Insecta, Hemiptera, Belostomatidae): the effect of adding continuous characters on its accuracy, Arthropod Systematics & amp; Phylogeny 81, pp. 1-34 : 1

Belostoma nieseri Ribeiro & Ferrari sp. nov.

Fig. 4F-J

Type locality.

Sinop Municipality, Mato Grosso State, Brazil.

Diagnosis.

Knobshaped ‘druckknopf’ on mesepimeron piriform, longer than wide. Arms of phallotheca divergent apically and broader, in dorsal view, covering entirely the sides of diverticulum; lateral margin of diverticulum of phallossoma weakly curved mesally, in dorsal view; diverticulum of phallosoma narrower than long, with its width less than one time its median length, in ventral view.

Description.

Male. Body length: 13.5 mm; greatest width of body: 6.2 mm. Female. Body length: 13.5 mm; greatest width of body: 6.4 mm. Body whitish brown. - Head. Anterior frontogenal suture shorter than posterior frontogenal suture; anteoculus slightly shorter than interoculus (from 0.93 to 0.96 times); length of visible segment I of rostrum from 0.80 to 0.84 times the length of visible segment II. - Thorax. Sclerite 1 of distal median plate moderately narrow, becoming somewhat broader medially, narrower than long; notch or indentation not developed along its basilateral margin, which is straight (Fig. 4F ); apical portion with distinct lobed process, broadly rounded; posterior portion articulated with veins 1A and 2A bearing a process directed posteriorly as long as half of longitudinal length of sclerite 1; process not indented apically and approximately straight; knobshaped ‘druckknopf’ on mesepimeron piriform, longer than wide (Fig. 2B ); prosternal carina somewhat elevated, not rectangular, pointed anteriorly, with its anterior margin smoothly curved, not projected anterad in lateral view (Fig. 4G ); apex without tubercles. - Abdomen. Pilosity covering about one third of connexivum, poorly developed on penultimate visible segment. - Male genitalia (Fig. 4H-J ). Arms of phallotheca diverging apically, shorter than its anterior region, covering sides of ventral diverticulum in dorsal view. Ventral diverticulum curved, becoming gradually narrowly rounded apically in lateral view; apical margin approximately straight, with small prominence in dorsal view; lateral margins slender, not thickened, curved at mid-length, slightly directly laterally in dorsal and ventral views. Width of diverticulum about 0.70 times its median length in ventral view. Ventroapical protuberance distinctly produced in lateral view, swollen, and approximately quadrangular in ventral view.

Remarks.

Belostoma nieseri sp. nov. may be mistakenly keyed to B. plebejum when using Nieser and Melo’s (1997: 60) key to Belostoma species because both species can measure between 13.5 and 15.0 mm. In fact, the body dimensions of members of B. nieseri sp. nov. resembles that of B. plebejum , but the former possesses a slightly narrower shape. Belostoma nieseri sp. nov. also shares with B. plebejum a ventral diverticulum with an apical margin that is approximately straight, with prominence in dorsal view, the ventroapical protuberance approximately quadrangular, somewhat swollen (especially in B. plebejum ), and the presence of mesal sulcus on ventral diverticulum in dorsal aspect. However, the arms of the phallotheca in B. plebejum are obviously parallel and slender, whereas they diverge apically and are broader in B. nieseri sp. nov.

Etymology.

The specific epithet is dedicated in honour of Dr Nico Nieser (the Netherlands) for his contributions to the study of giant water bug taxonomy.

Material examined.

Holotype. BRAZIL • 1 ♂; Mato Grosso State, Sinop Municipality ; 11°51.4859'S, 55°30.3359'W; Oct. 1974; M. Alvarenga leg.; J.R.I. Ribeiro det.; AMNH .- Paratype. BRAZIL • 1 ♀; Pará State, Jacareacanga Municipality ; 7°42'S, 57°36'W; Dec. 1968; M. Alvarenga leg.; J.R.I. Ribeiro det.; AMNH .

Figures

Figure 2. Mesepimeron and part of wing-to-body coupling mechanism. Part of the ' Druckknopf ' system component, located in the thorax. The system allows for the complete coupling of hemelytra to the dorsum. Character 27 was proposed by studying only the complementary structure of the apparatus, located in mesepimeron, not that on the wing apparatus. A Knobshaped ' Druckknopf ' system rounded, as long as wide B knobshaped ' Druckknopf ' system piriform, longer than wide.

Figure 4. Belostoma lanemeloi Ribeiro & Ferrari, sp. nov. and B. nieseri Ribeiro & Ferrari, sp. nov. A - E Male holotype of B. lanemeloi sp. nov. from Minas Gerais State, Brazil; F - J Male holotype of B. nieseri sp. nov. from Mato Grosso State. A Sclerite 1 of distal median plate of hindwing; B prosternal carina (lateral view); C - E male genitalia: phallosoma (phallotheca, dorsal arms, and diverticulum); C dorsal view; D ventral view; E lateral view; F sclerite 1 of the distal median plate of the hind wing; G prosternal carina (lateral view); H - J male genitalia: phallosoma (phallotheca, dorsal arms, and diverticulum); H dorsal view; I ventral view; J lateral view.