DIPLONYCHINI, Ribeiro & Ohba & Pluot-Sigwalt & Stefanello & Bu & Meyin-A-Ebong & Guilbert, 2018

Ribeiro, José Ricardo I., Ohba, Shin-Ya, Pluot-Sigwalt, Dominique, Stefanello, Fabiano, Bu, Wenjun, Meyin-A-Ebong, Solange E. & Guilbert, Eric, 2018, Phylogenetic analysis and revision of subfamily classification of Belostomatidae genera (Insecta: Heteroptera: Nepomorpha), Zoological Journal of the Linnean Society 182, pp. 319-359 : 333-335

TRIBE DIPLONYCHINI TRIB. NOV.

Type genus: Diplonychus Laporte, 1833

ported tree clades conflicting with all input trees was the response variable and datasets and quality of those data were used as factors, under the null hypothesis that the different dataset and the presence of missing data, with different methods of analysis used to infer phylogeny, did not affect the existence of phylogenetic signal and, in turn, the genus-level relationships in Belostomatidae . A failure to reject H 0 suggests strong congruence among such treatments. Abbreviations: d.f. = degree of freedom; SS = sum of squares; MS = mean of squares

Diagnosis: Diplonychini differs from other belostomatine suprageneric groups by the frons rounded or curved in dorsal view ( Fig. 9D, G, H), as well as the following male genitalia features: (1) the transverse bridge of basal plate of male genitalia clearly jointed and entire ( Fig. 16B); (2) plate of phallotheca as long as ventral diverticulum. Likewise, females of Diplonychini differ from the others by the presence of an ampulla located at the basal part of spermatheca ( Fig. 21A–C).

Distribution: Africa, Australia, East Indies, southern Asia ( Estévez & Ribeiro, 2011).

Description: Measurements. – Total length (from apex of head to apex of abdomen at rest): from 8.2 to 27.7 mm. General coloration. – Almost uniformly brown. External morphology. – Body ovate with wings usually covering abdomen. Frons rounded or curved ( Fig. 9D, G, H); vertex without median longitudinal carina ( Fig. 9D); antennae with segments 2 and 3 not flattened ventrally, with fourth segment similar to or slightly more bulbous than prolongations of segments 2 and 3 ( Fig. 11B); frontogenal suture slightly convergent and opened distally ( Fig. 9D). Pronotum without longitudinal median carina (e.g. Fig. 9D); prosternal keel usually poorly elevated, except for some Appasus species; hemelytra with rounded pruinose area; clamp of clavus with its outer projection overlapping inner part, always far from the margin of hemelytra ( Fig. 14A); its outer carina with three rows of microtrichiae along its external margin, covering small portion in dorsal view ( Fig. 13A, B); tile-like microtrichiae rounded at apex, never toothed along the margin of its apex ( Fig. 12B); foretarsi with two segments, externally usually appearing one-segmented, with segment 1 conspicuous, with two symmetrical grooves; claws vestigial; hind trochanters carinated, with short hairs or bristles along outer margins. Pilosity developed, covering half of connexivum, slightly constricted between spiracles, extending posteriorly along about half of or almost entire genital operculum; pubescence of ventral laterotergites 3 and 4 not attaining entire external margin; air straps lanceolate, with somewhat uniform width along its extension.

Male genitalia: Phallosoma fused to ventral diverticulum; arms of phallosoma well developed, extending nearly to apex of ventral diverticulum, enclosing ventral diverticulum in some Appasus ( Fig. 16E), somewhat laterally directed; orifice strongly developed, dorsally located on apex of phallosoma; ventral diverticulum contiguous, never bilobed, with its apex without ventroapical protuberance, not showing spines or tubercles in ventral view; transverse bridge of basal plate of male genitalia clearly jointed and entire ( Fig. 16B); plate of phallotheca somewhat developed, fused to or close to ventral diverticulum.

Female genitalia: Operculum of females with two tufts of setae on apex; apex of second valvulae with an inconspicuous spine; basal part of spermatheca without distinct apodemes, clearly with the presence of an ampulla; median vagina area below spermatheca without pouch ( Fig. 21A–C).

Taxonomic notes: In general, members of the new tribe Diplonychini share with W. rhomboides the prosternal carina poorly elevated (‘prosternal keel rounded’ according to Estévez & Ribeiro, 2011: 51) (character 27: 0> 1) and with H. pelocoroides the surface of apex of ventral diverticulum (in ventral view) without spines or tubercles (character 89: 0> 1). Our findings support Diplonychini trib. nov. as the sister group of the tribe Belostomatini by the following unambiguous homoplastic synapomorphies: (1) clamp of clavus with its outer projection not flattened, overlapping the inner part (similar to Fig. 14A) (character 31: 2> 3); and (2) outer carina of the clamp with three rows of microtrichiae along its external margin (character 32: 2> 1) ( Fig. 13A, B). The new tribe Diplonychini shares with other members of the subfamily Belostomatinae the foretarsi bearing both claws vestigial (character 44: 0> 3), phallosoma fused with ventral diverticulum (character 71: 0> 1), ventral diverticulum contiguous, never bilobed (character 85: 0> 1) ( Fig. 16E), and apex of second valvulae with a spine and/or protuberance (character 94: 0> 1). All morphological character states cited above are exclusive to this subfamily ( Fig. 6).