Rhagovelia sarawakensis, J. Polhemus & D. Polhemus, 1988

Zettel, Herbert, Laciny, Alice & Freitag, Hendrik, 2020, Review of the genus Rhagovelia Mayr, 1865 (Insecta: Heteroptera: Veliidae) in the Palawan biogeographic region, the Philippines, Raffles Bulletin of Zoology 68, pp. 810-837 : 813

Rhagovelia sarawakensis species group

Diagnosis. Body minute, length usually less than 3 mm; most species slender. Body colour mainly black, pronotum with short transverse stripe anteriorly. Antennae and legs black, often bright yellow at base. Metafemur of male moderately enlarged, but with rich dentition. Abdominal sternite 7 without paired tubercles. Paramere of male usually long and slender, and with ventrally curved hook or lobe at apex, but very short and reduced in Philippine taxa ( Fig. 7A–E ). Apterous morph: Pronotum short, length shorter than eye length (e.g., Figs. 1A–D , 2A, B ), in few extra-Philippine species slightly longer. Mesonotum fully or widely exposed. Macropterous morph: Wings uniformly dark. Forewing with 3 or 4 closed cells that distally reach apical half of wing. Wings of common dealate specimens broken off in distal half, distal of cells ( Figs. 2C, D , 3D ). Abdominal carina reaching posterior margin of tergite 3 (rarely onto tergite 2 only).

Distribution. Species of this group are distributed from India to Lombok, Borneo, and the southwestern Philippine Islands. A single record from Sulawesi (Polhemus & Polhemus, 1988) appears doubtful ( Nieser et al., 1997). John T. Polhemus (1990) correctly included the widely distributed Rhagovelia sumatrensis Lundblad, 1933 , in this species group, which covers almost the whole area of the group, except Borneo and the Philippines. Further species—many still undescribed— have restricted distributions on continental Southeast Asia, Sumatra, Borneo, and Greater Palawan.

Notes. The five Philippine species of this group, all restricted to the Palawan Region, seem to form an isolated clade and are well distinguishable from the Bornean species by a strong reduction of the parameres. Three species, Rhagovelia minutissima , R. palawanensis , and R. matillanoi , new species, share two very peculiar characteristics which are unknown from other species of the R. sarawakensis group, i.e., spikelike setae on the abdomen and a brush of long setae in distal half of mesofemora of females. The other two species R. estrella and R. abbreviata , new species, have some other important characters in common, e.g., carinate sternites and paramere shape of the males, although the female of the latter species displays a very peculiar habitus. While the species within each of these two clades show an allopatric distribution in general, two species of the first and the second clade, respectively, were occasionally collected in the same streams, thus demonstrating that even within the same species group there are sympatric, or even syntopic, species.

Figures

Fig. 7. Left parameres of Rhagovelia species, lateral view. A, R. minutissima; B, R. palawanensis; C, R. matillanoi, new species; D, R. estrella; E, R. abbreviata, new species; F, R. lansburyi; G, R. kawakamii hoberlandti; H, R. gapudi, new species.

Fig. 1. Habitus of Rhagovelia species. A, R. minutissima, apterous male; B, R. minutissima, apterous female; C, R. palawanensis, apterous male; D, R. palawanensis, apterous female.

Fig. 2. Habitus ofRhagovelia matillanoi, new species. A, apterous male; B, apterous female; C, macropterous dealate, male; D, macropterous dealate, female.

Fig. 3. Habitus of Rhagovelia species. R. estrella: A, apterous male; B, apterous female. R. abbreviata, new species: C, apterous male; D, macropterous dealate, male; E, apterous female; F, macropterous female.