This still unnamed new species (Fig. 4A) of the Ranatra gracilis Dallas, 1850 group (see Dallas 1850, Lansbury 1972) will be described and discussed further in an upcoming paper by Tran and Zettel (in prep.).

Figure 4.  

Habitus illustrations of Nepomorpha of Mindoro A. Ranatra sp. (R. gracilis group); B. Ochterus polhemusi; C. Asthenocoris luzonensis paradisianus; D. Aphelocheirus (s.str) freitagi; E. Anisops kuroiwae; F. Anisops rhomboides; G. Enithares martini mindoroensis; H. Hydrotrephes stereoides mindoroensis. Scale bars A 10 mm B–H 1 mm. A & C © NHMW Hemiptera Image Collection / photo: H. Bruckner, printed with permission.

Specimens were found in both flowing and calm littoral sections of shallow streams, such as in Fig. 1B. See Fig. 5 for current records.

Figure 5.  

Distribution of the collecting sites of Nepomorpha material treated in this study.

Figure 6.  

Selected habitus illustrations of Gerromorpha of Mindoro A. Hebrus sp.; B. Mesovelia vittigera; C. Hydrometra mindoroensis; D. Microvelia douglasi; E. Pseudovelia cf. curvata; F. Strongylovelia mindoroensis; G. Rhagovelia mindoroensis; H. Rhagovelia raddai. Scale bars 1 mm.

This is the first record of O. magnus Gapud & San Valentin, 1977 (see Gapud and San Valentin 1977) from Mindoro (Fig. 5). The species is Philippine-endemic, previously only known from Luzon – Mt. Makiling, Laguna; Humayao Creek, Cavite; Quezon; and in La Union (Gapud 2002).

Refer to Gapud (1986) for identification.

The specimens were found on wet rocks.

This species (Fig. 4B) is widely distributed in the Philippines. See Fig. 5 for our additional records.

Refer to Gapud (1981) for identification. In Mindoro, three species of Ochterus Latreille, 1807 are recorded so far, O. marginatus (Latreille, 1804) ssp. insularis Rieger, 1977, O. polhemusi Gapud, 1981 and O. philippinensis Kormilev, 1971 (Kormilev 1971, Gapud 1995, Gapud 2002).

We collected specimens in emergence traps spanned over littoral portions of small streams, on hygropetric rocks and along small rivulets. The species is generally found in banks of streams, ponds, lakes, freshwater marshlands and in association with waterfalls. It is also found in substrates that are muddy or sandy.

The species cannot be identified yet because the examination of comparative type material is needed, which is currently inaccessible. Nieser and Chen (2003) described four species from the Philippines but the Mindoro specimens differ from those.

All specimens were collected using a light trap, so their habitat cannot be accurately described. However, species of Micronecta Kirkaldy, 1897 are usually found in stagnant or shallow, slowly flowing waters (Nieser 1999). See Fig. 5 for current records, amongst them is site HR2 (Fig. 2B).

This subspecies is endemic to Mindoro (Zettel et al. 1999). See Fig. 5 for new records.

For identification, refer to the key by Zettel et al. (1999), a habitus illustration is provided in Fig. 4C. The genus Asthenocoris is endemic to the Philippines (Zettel et al. 1999). All material treated in here is brachypterous.

Asthenocoris luzonensis paradisianus Zetttel & Nieser, 2009 Fig. 4C is found in middle-sized streams running through secondary rainforest (Fig. 2B), as well as large, fast flowing streams, partly in secondary vegetation (Fig. 1C), but then only downstream of forested areas (Zettel et al. 1999). The specimens were retrieved in more or less fast flowing water from several substrates, foremost gravel, but also wood, leaf litter and root packs (Fig. 3G).

Aphelocheirus freitagi Zettel and Pangantihon, 2010 (see Zettel and Pangantihon 2010) (Fig. 4D) is endemic to Mindoro and was previously only known from its type locality, Malayas River in Victoria, Oriental Mindoro (Zettel and Pangantihon 2010). Here we present the first records from Baco and Roxas (Fig. 5).

For identification, refer to Zettel and Pangantihon (2010).

Aphelocheirus species Westwood, 1883 thrives in rather large, fast flowing rivers (Fig. 1D; Fig. 2A and B) with substrates consisting of a mixture of gravel and sand. The species is a typical benthic bottom dweller.

The species (Fig. 4E) is known from Luzon, Catanduanes, Leyte, Mindoro (with an additional record, see Fig. 5), Negros, Palawan, Burias, Bohol, Panay, Samar, Siargao and Mindanao (Zettel et al. 2012). It is also a widespread species in the Oriental realm with records from India, southern China, Iriomote (off Japan), Melaka, and Batu Berendam, Malaysia (Nieser 2004).

For identification, refer to the key by Zettel (2003a) and the original description (Matsumura 1915).

The single specimen was collected using a light trap not allowing for a specific microhabitat association. In general, representatives of this genus are found in isolated side pools (Fig. 3A) of streams and other stagnant water bodies (Zettel 2003a).

Anisops nigrolineatus Lundblad, 1933 (see Lundblad 1933) is widely distributed from India, Myanmar, Thailand, Brunei, Java and up to the Philippines (Zettel et al. 2012), with only a single previous record from Sibuyan Island (Nieser and Chen 1999). This is the first record from Mindoro Island (Fig. 5).

For identification, refer to the key by Zettel (2003a).

The specimen was found in a small side pool near a slow-flowing stream.

The species (Fig. 4F) is recorded from Brunei, Borneo, Sulawesi and the Philippines (Nieser and Chen 1999, Chen et al. 2005). Previous Philippine records refer to Leyte, Mindanao, Palawan and Tawi Tawi (Zettel et al. 2012). This is the first record from Mindoro (Fig. 5).

For identification, refer to the key by Zettel (2003a). Its specific epithet, rhomboides, refers to the lozenge-shaped fossa on the tylus (Nieser and Chen 1999), which is a good character for identification.

Anisops rhomboides Nieser & Chen, 1999 (see Nieser and Chen 1999) is found in a variety of shallow, stagnant freshwater bodies, such as lakes, ponds, carabao puddles, marsh land and moats (Nieser and Chen 1999).

This species (Fig. 4G) is widely distributed in the Philippines, but the subspecies is endemic to Mindoro (Nieser and Zettel 1999). See Fig. 5 for the new records.

For identification, refer to the key by Nieser and Zettel (1999).

Enithares martini mindoroensis Nieser & Zettel, 1999 (see Nieser and Zettel 1999) can be found in calm shores and connected and isolated pools on the banks of streams (Nieser and Zettel 1999, current study).

The subspecies (Fig. 4H) is endemic to Mindoro Island. See Fig. 5 for new records. Other Hydrotrephes steroides Zettel, 2003 (see Zettel 2003b) subspecies occur in north and central Luzon, namely ssp. montanus and ssp. steroides.

For identification, refer to the key by Zettel (2003b).

Hydrotrephes stereoides Zettel, 2003 is mainly associated with lentic sections of running waters, swimming actively at the edges of plant material, rarely benthic in running waters. We found most specimens attached to wood in clean mountain rivers.

The species is widely distributed in the Philippines, except for Palawan. This is the first record of this species in Mindoro (Fig. 7). It was previously recorded from Biliran, Bohol, Camiguin, Catanduanes, Cebu, Leyte, Luzon, Masbate, Mindanao, Negros, Panay, Polillo, Poro, Samar and Siquijor (Zettel 2006).

Figure 7.  

Distribution of the collecting sites of Gerromorpha material (part 1) treated in this study.

For identification, see Zettel (2006). The parameres have long setae both in the lateral and apical portions. Most of the species have straight parameres and only few were directed mesally. In contrast to the Hebrus harrisi complex, this species has a less distinct endocorium with only a small and elongate white spot. All specimens examined were macropterous.

Hebrus philippinus Zettel, 2006 (see Zettel 2006) is quite euryoecious and can also thrive in anthropologically-disturbed habitats. It is commonly found on the banks of running waters and more rarely in nearby stagnant waters. Unlike other Hebrus species, it is often found in sunny and dry areas. We obtained most records from hygropetric microhabitats.

The Hebrus harrisi complex is discussed by Zettel (2004a), Zettel (2006). Due to the lack of specimens for comparison, our material (Fig. 6A) cannot be identified to species level. All specimens examined were macropterous.

The specimens (Fig. 7) were found at the banks of more or less fast flowing sections of rivers of small to medium size.

Mesovelia horvathi (s.l.) Lundblad, 1933 (see Lundblad 1933) was reported from Australia, China, India, Indonesia, Japan, Malaysia, Philippines (see Fig. 7 for new records), Sri Lanka, Singapore, Thailand, and Vietnam (Lundblad 1937, Chandra and Jehamalar 2011, Yang and Murphy 2011, Zettel 2014).

For identification, refer to the key by Yang and Murphy (2011). More recently, Jehamalar et al. (2019) have shown that Mesovelia horvathi consists of a complex of closely-related species. At least two species of this complex occur in the Philippines. Their correct names remain uncertain. As a result, we refrain from concluding that the previous records from other areas in the Philippines and specimens in this study are indeed M. horvathi.

Mesovelia horvathi Lundblad, 1933 is common in plains and mountains in stagnant, slow flowing and even in brackish water (Yang and Murphy 2011). We found the species in similar, partly identical habitats like Mesovelia vittigera, but so far, never syntopic with the former species.

The species (Fig. 6B) is widely distributed in the tropics and subtropics of the Old World, including the Philippines (Zettel 2014). See Fig. 7 for additional records.

For identification, refer to the key by Yang and Murphy (2011). All specimens examined were apterous.

Mesovelia species are commonly found amongst marginal vegetation in standing waters of ponds and streams. Mesovelia vittigera Horváth, 1895 (see Horváth 1895) can also be found in brackish-water habitats (Yang and Murphy 2011). We found several specimens on shaded, wet rocks and at the stream littoral with mineral substrates (Fig. 1B).

Hydrometra lineata Eschscholtz, 1822 (see Eschscholtz 1822) is widely distributed in the Philippines (see Fig. 7 for new records), the Oriental Realm, Wallacea and New Guinea (Polhemus and Lansbury 1997, Gapud et al. 2003).

For identification, refer to the key by Gapud et al. (2003). All specimens examined were macropterous.

The species is often found in large stagnant water bodies and rarely seen in running waters; however, all our samples are from stream banks.

Hydrometra mindoroensis Polhemus, 1976 (in Polhemus and Reisen 1976) (Fig. 6C) is a widespread species in the Philippines and neighbouring areas (Borneo, Sulawesi, New Guinea) (Polhemus and Lansbury 1997, Gapud et al. 2003).

For identification, refer to the key by Gapud et al. (2003).

This species can be found in both stagnant waters and edges of streams and rivers (Gapud et al. 2003). We found the species in shaded hygropetric sites and at stream banks with mineral and organic substrates (Fig. 1B).

This species (Fig. 6D), which was originally described from Japan (Scott 1874), is widely distributed in the Oriental, Australian and Melanesian Regions reaching eastwards to the remote islands of the West Pacific Region (Andersen and Weir 2003). See Fig. 7 for the additional records.

See Andersen et al. (2002) for identification. The species is rarely collected in the Island.

The species was found on stream banks, specifically in side pools (Fig. 3B), such as at site BR3 (Fig. 2A).

The typical form is only known from the Mountain Province in northern Luzon (Hecher 2006). See Fig. 7 for the collecting sites of the slightly varying Mindoro material.

The specimens (Fig. 6E) closely resemble those of Pseudovelia curvata Hecher, 2006 following the key in Hecher (2006), displaying the following characters: first metatarsal segment devoid of a tuft of very long setae basally; first and second metatarsal segment with a row of long setae over entire length; and metatarsus about half as long as metatibia. However, the pygophore of males has long, bristle-like setae on its caudo-lateral margin like P. gapudi Hecher, 2006. Given the lack of any records, except for the specimens in hand and the type material from northern Luzon, it must remain unsolved if the material is conspecific or represents a new, but related species. This variation is only recognised in our specimens from Mindoro.

The specimens were found at banks of creeks and rivers, both in calm and flowing sections.

Strongylovelia mindoroensis Lansbury & Zettel, 1997 (see Lansbury and Zettel 1997) (Fig. 6F) is endemic to Mindoro and only known from the type locality in Puerto Galera (Lansbury and Zettel 1997) and our records from Baco and Roxas (Fig. 7).

For identification, refer to the key by Zettel (2003c).

The species was found in slow flowing water and a residual pool with floating plants.

Rhagovelia mindoroensis (Fig. 6G) is an endemic species in Mindoro (Zettel 1994). See Fig. 8 for our additional records.

Figure 8.  

Distribution of the collecting sites of Gerromorpha material (part 2) treated in this study.

For identification, see Zettel (1994).

Rhagovelia mindoroensis Zettel, 1994 (see Zettel 1994) is usually found in secondary forests and in anthropogenic terrains close to the coast. They particularly inhabit still waters sections of streams (Zettel 1994). We also found it in small side pools of medium-sized rivers and creeks. The collection at site TDR4 (Fig. 2C) at 700 m altitude is surprising.

Rhagovelia raddai Zettel, 1994 (see Zettel 1994) (Fig. 6H) is endemic to Mindoro (Zettel 1994). See Fig. 8 for additional records.

For identification, see Zettel (1994).

The species is commonly found in moderately fast flowing creeks and lotic sections of the river (Zettel 1994), such as in our study.

Rhagovelia potamophila Zettel, 1996 (see Zettel 1996) is endemic to Mindoro (Freitag and Pangantihon 2010). We present one additional record (Fig. 8).

For identification, see Zettel (1996), a habitus illustration is provided in Freitag and Pangantihon (2010).

The specimens were found neustic on flowing water near root packs of a small river in a rural area (Fig. 1B).

Rhagadotarsus (Rhagadotarsus) kraepelini Breddin, 1905 (see Breddin 1905) is a widespread species in southern and south-eastern Asia and Micronesia (Polhemus and Karunaratne 1993). In the Philippines, R. kraepelini is distributed throughout the country, but the limits of its distribution in the Philippines are still unclear (Zettel 2014). See Fig. 8 for the additional record.

For identification, refer to the key by Polhemus and Karunaratne (1993).

The specimens were found amongst floating water plants in a residual pool of a dried-up lowland creek in a rural area.

The species (Fig. 9A) is widespread in the Philippines, Maldives, India, Sri Lanka, southern China and Indonesia (Damgaard et al. 2014), with the first records from Cambodia recently documented by Zettel et al. (2017). See Fig. 8 for our additional records.

Figure 9.  

Selected habitus illustrations of Gerromorpha of Mindoro A. Limnogonus nitidus; B. Limnometra nigripennis nigripennis; C. Tenagogonus sp. (mutilated specimen); D. Rheumatogonus luzonicus; E. Metrocoris tenuicornis. Scale bars 10 mm.

Refer to Cheng et al. (2001) for the identification.

In the Oriental realm, most species of Limnogonus Stål, 1868 prefer sheltered places in standing waters, which makes them somewhat gregarious. Limnogonus nitidus (Mayr, 1865) (see Mayr 1865) and L. fossarum (Fabricius, 1775) (see Fabricius 1775) are probably the only Oriental species of the genus that successfully colonise intermittent habitats.

Limnometra nigripennis nigripennis Mayr, 1865 (see Mayr 1865) (Fig. 9B) is endemic and widespread in the Philippines. Records are available from Biliran, Bohol, Camiguin, Guimaras, Leyte, Luzon, Mindanao, Mindoro (see Fig. 8 for our additional records), Negros, Panay, Polillo, Sibuyan, Tablas, Ticao, as well as unpublished records from Masbate (Zettel 2014 and references therein).

For identification, refer to Zettel (2004b).

Limnometra nigripennis Mayr 1865 is amongst the most widespread and abundant Gerromorpha of Philippine running waters (Zettel 2004b, Zettel 2014). It exhibits higher tolerance to environmental disturbances in streams than other species. However, we recorded it predominantely from clean streams (Fig. 2C, D). Lentic sections of very small to medium-sized streams and pools associated with running water are its typical habitats (Zettel 2014).

This genus is in need of revision (Zettel 2014). The specimens (Fig. 9C) probably belong to a new species related to Tenagogonus bergrothi Hungerford & Matsuda, 1958 (see Hungerford and Matsuda 1958), from Luzon. The genus is widespread throughout the Afrotropical, Oriental and Australian Regions, extending eastwards up to Fiji (Damgaard et al. 2014). Fifteen species are known in the Malesian Region, including the Philippines (Chen et al. 2005).

The collected specimens were found in small forest streams, a common habitat of representatives of the genus.

Rheumatogonus luzonicus (Kirkaldy, 1909) (see Kirkaldy 1909) (Fig. 9D) is endemic to the Philippines and has been recorded from Luzon, Mindanao, Mindoro (Freitag and Pangantihon 2010, see Fig. 8 for additional records), Negros and Panay (Chen and Nieser 2002). Some unpublished records from Catanduanes, Marinduque, Sibuyan, Ticao, Cebu, Samar, Leyte, Mindanao, Siquijor and Poro have also been recognised belonging to this species (Zettel 2014).

For identification, refer to Chen and Nieser (2002).

The specimens were collected from the surface and littoral of calm and moderately fast flowing creeks and medium-sized rivers (Fig. 1A, B). In general, Rheumatogonus Kirkaldy, 1909 species inhabit mountain streams, creeks and waterfalls in the Oriental Region, specifically the shaded, steady slow-lotic sections of such watercourses (Chen et al. 2005).

Metrocoris tenuicornis Esaki, 1926 (see Esaki 1926) (Fig. 9E) is a widspread species in western India, southern China, mainland southeast Asia, Sumatra, Java and Borneo, but only known so far from Mindoro and Greater Palawan, in the Philippines (Chen and Nieser 1993, Freitag and Zettel 2012).

For identification, refer to Chen and Nieser (1993).

Quiet bays of smoothly-flowing streams and the edge of large rocks in the middle of streams are the preferred habitats of Metrocoris Mayr, 1865 species (Chen and Nieser 1993), such as the records presented here (Fig. 8).