Rhagovelia matillanoi, Zettel & Laciny & Freitag, 2020

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 : 816-820

Rhagovelia matillanoi , new species

( Figs. 2A–D , 7C , 8A , 9A, B , 10A–C , 11B , 14A–C )

Rhagovelia cf. palawanensis – Freitag & Zettel, 2013: 65–66.

Etymology. The species is named for Joie Matillano, formerly faculty member and collaboration partner of the senior authors, in recognition of his outstanding contributions to the survey and protection of the Palawan fauna. We particularly appreciate his dedicated encouragement of students in fieldwork and biodiversity studies, such as in our joint workshop “Freshwater Invertebrates: their Taxonomy, Diversity and Ecology” in 2007, which also yielded additional data and material for this paper.

Type material. Holotype (apterous male; NMNH) labelled “PHIL: Palawan, Roxas, Bagong Bayan, creek downstream of Ilian Falls , 10°25′40″N 119°33′25″E, ca. 50 m a.s.l., 17.XI.1995, leg. J. Mendoza (# 129)” . Paratypes ( ADMU, NHMW, NMNH, UPLB, PCSD): 56 apterous males, 6 macropterous males, 76 apterous females, 11 macropterous females collected from the same locality (partly labelled “ Bagong Bayan Falls ”); 1 apterous male, 5 macropterous males from northern Palawan, El Nido, Barutuan, road km 291.5, small lowland river below irrigation dam, ca. 11°18′N, 119°27′E ; 1 apterous male from northern Palawan, El Nido, Pasadeña, Nagkalit-Kalit Falls , ca. 11°15′N, 119°26′E ; 24 apterous males, 3 macropterous males, 42 apterous females, 2 macropterous females from northern Palawan, 20 km N Taytay, Pularaquin, Canequi Falls , 10°56′59″N, 119°28′09″E, 25 m a.s.l. ; 15 apterous males, 1 macropterous male, 28 apterous females from central Palawan, Puerto Princesa, Marofinas, Panaguman River , 10°15′09″N, 118°58′03″E ; 1 macropterous female from central Palawan, Puerto Princesa, Cabayugan, Cabayugan River S of Martarpi, 10°09′47″N, 118°50′37″E, 37 m a.s.l. ; 14 apterous males, 14 apterous females from central Palawan, Puerto Princesa, Cabayugan, SSW Martarpi, Cabayugan River , 10°09′46″N, 118°49′29″E ; 1 macropterous (delate) from central Palawan, Puerto Princesa, Concepcion, Tarabanan River , ca. 6 km upstream Highway, 10°03′47″N, 119°00′53″E, 200 m a.s.l.

Type locality. Northern Palawan, Roxas municipality, barangay Bagong Bayan, Ilian Falls , 10°25′40″N, 119°33′25″E, 40 m a.s.l.

Diagnosis. Very small, body length of male 1.97–2.11 mm (apterous), 2.13–2.28 mm (macropterous), female 2.27–2.38 mm (apterous), 2.27–2.47 mm (macropterous). Mesocoxa (usually), mesotrochanter, metatrochanter, and base of metafemur yellow; mesotrochanter apically with black ring. Short, stout, spike-like setae numerous on connexiva in apterous morph, also on mesonotum and tergites (in male until tergite 7, in female until tergite 4; with transverse row on tergite 1). Male: Sternites without median carina. Sternites 6 and 7 with distinct paired impressions, so that the medial zone appears elevated. Segment 8 ventrally flat. Paramere: Fig. 7C . Apterous and macropterous females: Mesofemur with brush of long setae in distal half. Apterous female: Abdomen ( Fig. 10A, B ) not shortened, with strong constriction at base of sternite 7. Posterior edge of laterotergite 5 with few medioposteriorly directed setae. Connexival corner (segment 7) with distinct tuft of black setae. Tergites 7 and 8 with long pilosity. Gonocoxa with few setae at dorsal edge.

Description of apterous male. Measurements of holotype: Body length 2.06; maximum body width (at metapleura) 0.84. Head length 0.28, width 0.61; minimum eye distance 0.15. Pronotum length 0.19, width 0.66. Lengths of antennomeres: I 0.53, II 0.24, III 0.36, IV 0.35. Lengths of leg segments: profemur 0.63, protibia 0.66, protarsus 0.02 + 0.02 + 0.16, mesofemur 1.03, mesotibia 0.80, mesotarsus 0.05 + 0.31 + 0.50, metafemur 0.78, metatibia 0.73, metatarsus 0.04 + 0.05 + 0.19.

Measurements of paratypes (n = 10): Body length 1.97–2.11; maximum body width (at metapleura) 0.80–0.88. Head width 0.56–0.61. Pronotum length 0.16–0.19, width 0.63–0.69.

Colour: Black. Pronotum with transverse orange mark in centre, laterally reaching level of medial eye margin. Basal third to half of antennomere 1, distal corner of proepisternum, all coxae (mesocoxa in some specimens infuscated) and trochanters (mesotrochanter with distal black ring), basal half of profemur, and basal quarter to third of metafemur yellow. Rostrum yellowish to dark brown. Juga brown to blackish.

Pilosity: Sides of pronotum, propleuron, and mesopleuron with long black setae. Thorax dorsally with short greyish pilosity. Abdominal tergites in addition to short appressed pilosity with slightly longer, subdecumbent, black setae. Short spike-like setae numerous on connexival margins and all tergites, scattered and individually varying in their presence on lateral parts of sternites 3–7, on hind margins of thoracic nota (laterally) and on thoracic pleura (dorsally), in most specimens rather numerous on metapleuron.

Structures: Head slightly broader than anterior margin of pronotum. Juga flat, inclined, and relatively broad, without spinulae. Pronotum very short, along midline about 0.7 times as long as head. Mesonotum along midline about 3.0 times as long as pronotum. Proepisterna bearing numerous small black spinulae, in some specimens lacking in posterolateral corner.

Profemur on extensor side with very shallow concavity. Metacoxa and metatrochanter with few small black spinulae. Hindleg ( Fig. 9A ) rather uniform; femora moderately thickened, longest spine near mid-length; basal row consisting of ca. 8–13 small spinules (in some specimens the distal spinule slightly longer than others); posterodistal row consisting of long first tooth followed by 5–8 teeth of strongly decreasing length; anterodistal row often inconspicuous, consisting of ca. 1–6 short teeth or spinules. Metatibia stout, straight or weakly curved, with strong dentition at flexor side.

Laterotergites almost horizontal. Tergite 7 about 2.0 times as long as tergite 6, and 1.0 times as long as broad. Abdominal venter without median carina. Sternites 6 and 7 with shallow, but distinct paired impressions, medial zone between them appearing elevated. Proctiger slender, lateral wings weakly developed ( Fig. 8A ). Paramere short, U-shaped, apex hardly protruded ( Fig. 7C ).

Description of apterous female. Measurements of paratypes (n = 10): Body length 2.27–2.38; maximum body width (at metapleura) 0.97–1.05. Head width 0.61–0.66. Pronotum length 0.17–0.19, width 0.69–0.73.

Colour: as in male. Description of macropterous female. Measurements of paratypes (n = 10): Body length 2.27–2.47; maximum body

Pilosity: Sides of pronotum, propleuron, and mesopleuron width (at pronotum) 1.03–1.08. Head width 0.61–0.64. with long black setae. Pro- and mesonotum with dense fine Pronotum length 0.97–1.06. appressed pilosity. Mesofemur with strongly developed brush of long setae ventrally over distal half. Metanotum and Colour: As in macropterous male. tergite 1 only with few appressed hairs. Tergites 2–6 bare; tergites 7–8 with dense, posteriorly directed pilosity, that on Pilosity: Setae on pronotum and forewings as in macropterous tergite 8 longer. Laterotergites with fine pilosity laterally, on male. Pilosity on tergite 7 absent, on tergite 8 reduced. segment 4 longer and denser; posterior corner of segment 5 Sternites 5–7 at connexival margins with long, posteriorly with a few posteromedially directed setae; posterior corner directed setae, most prominently developed on sternite 7 (Fig. of segment 7 with distinct tuft of posterodorsally directed 10C); tuft at connexival corner developed, but weaker than in black setae ( Fig. 10B ). Gonocoxa with numerous long setae apterous morph. Pilosity of gonocoxa as in apterous morph. ventrally, but at most with few setae at dorsal edge. Short and stout, spike-like setae numerous on connexiva until Structures: Strongly deviating from apterous female as the segment 5, scattered between pronotum and tergite 4, on abdomen is not constricted posteriorly. Pronotum large, with thoracic pleura, and lateral parts of sternites 2–5. protruding humeri. Forewing as in male. Hindleg slightly slenderer than in apterous female. Abdomen with slightly

Structures: Body slightly broader than in male; abdomen and evenly convergent connexival margins. Tergites 7 and more elongated. Head distinctly broader than anterior margin 8 of similar size, each slightly shorter than wide. of pronotum. Pronotum very short, along midline about half of head length. Mesonotum along midline about 3.7 Comparative notes. This new species forms a complex times as long as pronotum. Mesonotum bulging, posteriorly with R. minutissima from Busuanga and R. palawanensis declivitous; hind margin slightly concave at middle. from southern and central Palawan. Leg colour is identical to R. minutissima and structural differences are listed in key

Mesofemur moderately flattened in distal half. Metafemur couplet 6. Structurally, R. matillanoi , new species, appears ( Fig. 9B ) slender, without basal and anterodistal rows of more similar to R. palawanensis , and reliable differences teeth; posterodistal row consisting of one long tooth at mid- (besides leg colour) were only detected in apterous females: length of femur followed by 2–5 shorter teeth of decreasing In R. palawanensis , the gonocoxa bears a thick brush of length. Metatibia toothless, straight. setae on its dorsal edge, which is lacking in R. matillanoi , new species. In R. matillanoi , new species, the posterior

In dorsal aspect ( Fig. 10A ) abdomen broad anteriorly and corner of the laterotergite bears a few thin posteromedially strongly narrowed posteriorly, with strong constriction at base directed setae (absent in very few specimens but possibly of segment 7. Connexival margins strongly convergent until broken off), which are absent in R. palawanensis . segment 5, subparallel at segments 6 and 7. Laterotergites 2–4 strongly inclined on segments, 5–7 nearly vertical. Tergites Habitats. This species was found in rather undisturbed, 1 and 4 slightly, transversely elevated, tergites 2 and 3 flat shaded streams running through forests ( Fig. 14A, C ). Along or slightly depressed; tergite 5 trapezoidal, with median the Tarabanan River, and especially the well-studied blunt carina; tergite 6 developed as a narrow stripe; tergite Cabayugan River in the Puerto Princesa Subterranean River 7 about 1.5 times as long as tergite 6 and about 1.5 times National Park, R. matillanoi , new species, was restricted as long as wide; tergite 8 as long as tergite 7 and slightly to the upper, well-shaded river courses (see Freitag, 2004: broader. Connexival corner in lateral view blunt. Gonocoxa sites “CR1”, “CR2”) in forested areas with heterogeneous plate-like. Proctiger small, knob-like. streambed morphology and moderately to fast-flowing water. At site “CR1”, all except one specimen were retrieved by

Description of macropterous male. Measurements of drift nets installed in a fast-flowing creek section. paratypes (n = 8): Body length 2.13–2.28; maximum body width (at pronotum) 0.97–1.05. Head width 0.58–0.63. Distribution. Palawan Island (North) ( Fig. 11B ). Pronotum length 0.97–1.03. Rhagovelia estrella Zettel, 1994

Colour: As in apterous male. Forewings black, without ( Figs. 3A, B , 7D , 11C , 12A , 13A ) pale streak. Rhagovelia estrella Zettel, 1994b: 44–45 ; Chen et al., 2005: 438.

Pilosity: Hind margin of pronotum with some moderately long, posteriorly directed black setae. Basal veins of forewing Material reported by Zettel (1994b). Holotype (apterous with long black pilosity. male, NHMW) and paratypes (46 apterous males, 20 apterous females, 1 macropterous male, NHMW, FMNH, NCTN,

Structures: Pronotum large, with protruding humeri. Forewing BPBM, UPLB) from Palawan, 7 km N Narra, Estrella Falls. with 3 or 4 closed cells, in dealate specimens broken behind level of segment 6. Metafemur slender when compared to Additional material examined ( ADMU, JTPC, NHMW, apterous male. Metatibia straight or weakly curved. In dealate UPLB). 1 apterous male from Palawan, Taritien River at specimens tergite 7 visible and shiny in middle. Trident Mine , 7 km NW of Narra; 1 apterous male from central Palawan, Montible , at Napsan Road km 29, large river, 9°41′25″N, 118°37′26″E, 30 m a.s.l. ; 31 apterous males, 14 apterous females from central Palawan, Napsan, Napsan Road km 43, Salakot Waterfalls , 9°42′10″N, 118°31′17″E, 310 m a.s.l.

Diagnosis. Small, body length of male 2.28–2.47 mm (apterous), 2.50 mm (macropterous), female 2.53–2.75 mm (apterous). Mesocoxa, (base of) mesotrochanter, and base of metafemur yellow. Body without spike-like setae. Male: Sternites 2–7 with sharp median carinae. Sternite 7 with large paired impressions accentuating median carina. Segment 8 ventrally convex. Paramere: Fig. 7D . Apterous and macropterous females: Mesofemur without brush of long setae in distal half. Apterous female: Abdomen not shortened, without distinct constriction at base of sternite 7. Connexival corner (segment 7) without distinct hair tuft.

Descriptive notes. Measurements: Apterous males (n = 10): Body length 2.28–2.47; maximum body width (at metapleura) 0.91–0.97. Head width 0.66–0.72. Pronotum length 0.19–0.22, width 0.72–0.78.

Apterous females (n = 10): Body length 2.53–2.75; maximum body width (at metapleura) 1.03–1.11. Head width 0.69–0.75. Pronotum length 0.19–0.22, width 0.73–0.81.

Macropterous male (n = 1): Body length 2.50; maximum body width (at pronotum) 1.06. Head width 0.67. Pronotum length 1.06.

Morphological and comparative notes. Only a single macropterous individual is currently known ( Zettel, 1994b). The carinate sternites of the males suggest a close relationship of R. estrella and R. abbreviata , new species, but the females of these two species are strongly different. For differentiation, see the characters listed in the key.

Habitats. The habitat requirements appear to be similar to that of R. palawanensis , as the two species partly occurred in the same collecting sites, including moderately fast-flowing, large unshaded streams ( Fig. 12A ) as well as their smaller, more torrential tributaries ( Fig. 13A ). When occurring together, R. estrella was less abundant than its congener. No records on the particular microhabitats are available.

Distribution. Palawan Island (Central) ( Fig. 11C ).

Figures

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

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. 8. Proctiger of Rhagovelia species, dorsal view pilosity omitted. A, R. matillanoi, new species; B, R. abbreviata, new species; C, R. lansburyi; D, R. kawakamii hoberlandti; E, R. gapudi, new species.

Fig. 9. Hindlegs of Rhagovelia species, showing characteristic armatures pilosity omitted. A, R. matillanoi, new species, apterous male; B, R. matillanoi, new species, apterous female; C, R. abbreviata, new species, apterous male; D, R. abbreviata, new species, macropterous male; E, R. abbreviata, new species, apterous female; F, G, R. gapudi, new species, apterous males, two morphs; H, R. gapudi, new species, apterous female.

Fig. 10. Abdominal terminalia of females of Rhagovelia species, pilosity partly omitted. A–C, R. matillanoi, new species, arrow in A pointing to characteristic setae; D–F, R. abbreviata, new species; G–I, R. gapudi, new species, arrows in H, I pointing to concave ventral outline of gonocoxa. A, D, G, apterous specimen, dorsal aspect; B, E, H, apterous specimen, lateral aspect; C, F, I, macropterous specimen in 48 dealate, lateral aspect.

Fig. 11. Area and distribution maps of Rhagovelia species. A, overview of the Palawan Region with major islands and towns, insert showing the location of the area within the Philippines as well as the northern part of Borneo belonging to Malaysia; B, allopatric distribution of the species of the R. sarawakensis group related with R. minutissima; C, allopatric distribution of the species of the R. sarawakensis group related with R. estrella; D, distribution of R. lansburyi; E, distribution of R. kawakamii hoberlandti; F, distribution of R. gapudi, new species.

Fig. 14. Habitats. A, the stream below the Ilian Falls northeast of Roxas, running through a forested watershed area, is the type locality of R. matillanoi, new species, and R. abbreviata, new species; R. kawakamii hoberlandti was also found in quiet bays. B, C, the same three species were collected in the stream below the Canequi Falls at Pularaquin, about 20 km north of Taytay.

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.

Fig. 12. Habitats. A, a larger river at Napsan Road, kilometre 29, with high water level after heavy rain; R. palawanensis and R. estrella were recorded in quieter rock pools and between flooded vegetation. B, a small streamlet at Calatoboc Bridge over Northern National Highway was inhabited by R. kawakamii hoberlandti and R. gapudi, new species. Whereas the first species is euryoecious, R. gapudi, new species, prefers such small running waters.

Fig. 13. The Salakot Waterfalls and the stream below at Napsan Road, kilometre 43. In the various habitats, R. estrella, R. kawakamii hoberlandti, and R. lansburyi were recorded. Deep rock pools as shown in B are characteristic habitats for R. lansburyi.