Paraplea melanodera Cook, 2020

Cook, Jerry L., Sites, Robert W. & Vitheepradit, Akekawat, 2020, The Pleidae (Hemiptera, Heteroptera) of Thailand, with the descriptions of two new species and a discussion of species from Southeast Asia, ZooKeys 973, pp. 35-68 : 35

Paraplea melanodera Cook sp. nov. Figures 18 , 19, 20 , 21 , 22-23 , 24D

Description.

All measurements are in millimeters and were taken from 47 adult specimens from Thailand as reported in the distribution portion of this paper. Specimens used for this description are deposited at UMC and SHSU.

Body size. Total length, 1.28-1.66 (average=1.49) (Fig. 18A, B, D ).

Color. Color may vary slightly among individuals (Fig. 18A, D ) but all specimens with a dark brown to black band at back of vertex of head. Base color of body usually light tan to golden-tan with some darker brown markings (Fig. 18A ); although, some specimens have a base color almost white (Fig. 18C, D ). A few specimens with weak banding pattern of hemelytra (Fig. 18A, C ); honeycombing present but often sparse and difficult to see in some specimens.

Head. Head generally light brown, without markings except distinctive dark band posteriorly. Antenna three-segmented. Head width at widest point including eyes 0.62-074 (average 0.68), head width at narrowest point between eyes, 0.29-0.39 (average 0.34), OI 46-52 (average 49).

Pronotum. Base color brown to light tan (Fig. 18C ), usually with lighter colored honeycombing apparent although often not observable throughout; most specimens without dark spots; without distinct humeral or lateral bulges: punctures present, ~ 0.02, spacing between punctures ~ 0.02; if honeycombing present, punctures located between honeycomb bars (Fig. 18C ); pronotum width 0.66-0.90 (average 0.78); pronotum length 0.42-0.57 (average 0.50); PI 56-73 (average 64).

Wings. Hemelytra complete to posterior; punctures evenly dispersed with only small distance between punctures, punctures not in rows, ~ 0.02 diameter, evenly spaced (Fig. 18A, C, D ); underlying honeycomb structure sometimes present; claval suture present (Fig. 18C, D ); scutellum with distinct punctures, usually without darkened center, more widely spaced than other punctures, punctures not in apparent order; scutellum base color more yellow than hemelytra; hemelytra without spots near margin but sometimes with broad vertical bands (Fig. 18A, C ); shape of hemelytra flat dorsally with posterior face at almost 45° angle (Fig. 18A, D ); scutellum often slightly wider than long, sometimes as long as wide (Fig. 18C ), length 0.28-0.39 (average 0.34); scutellum width 0.31-0.48 (average 0.39); SI 103-128 (average 115). Hind wings membranous, fully developed, completely concealed by hemelytra.

Legs. Coxae and trochanters relatively very long compared to most pleid species (Fig. 19 ); hairs numerous on all coxae, relatively long and common on tibiae an tarsi, thickened on prothoracic tibia and tarsus; small spines on prothoracic and mesothoracic femora, small number longer on prothoracic femur; base of prothoracic tibia darker than other parts of leg. Typical leg measurements: prothoracic leg coxa 0.20, trochanter 0.11, femur 0.42, tibia 0.29, first tarsomere 0.03, second tarsomere 0.13, pretarsal claw 0.07; mesothoracic leg coxa 0.25, trochanter 0.08, femur 0.35, tibia 0.29, first tarsomere 0.02, second tarsomere 0.14, pretarsal claw 0.06; metathoracic leg coxa 0.19, trochanter 0.13, femur 0.39, tibia 0.42, first tarsomere 0.03, second tarsomere 0.14, third tarsomere 0.15, pretarsal claw 0.12; several long hairs along ventral side of trochanter, femur, tibia and tarsus, especially along hind tarsus where some hairs reach 0.18.

Median ventral keel. Thoracic portions distinctively shaped but often hidden by enlarged coxa; prosternal keel broadly rounded, with irregular edges; mesosternal keel narrow, distinctive finger-like projection posteriorly; metathoracic keel segment somewhat rounded with prominent cleft towards center, sometimes appearing to almost overlap first abdominal section; abdominal keel I somewhat rectangular, with distinct tooth, abdominal keel II somewhat square, posterior tooth, abdominal keel III and IV shaped like posteriorly projecting teeth, IV longer than III (Fig. 20 ).

Characters of female. Ovipositor expanded apically (Fig. 21 ); five distinct teeth along posterior border (apical row), two large teeth in ventral half, three smaller teeth in dorsal half; three teeth on ventral margin, decreasing in size basally. Two rows of three teeth each away from apex, three primary and three secondary; most specimens with one tertiary tooth; several hairs along basal region of gonapophysis 1 that can be seen under high magnification. Subgenital plate triangular, slightly wider than long (Fig. 22 ), width ~ 0.42, length ~ 0.37; central anterior area of plate raised above other parts, with v-shaped sub-apical prominence; rugose in basal one third; central region towards apex mildly rugose; two distinct tufts of longer hairs on each side of center near apex; other single hairs present, especially toward apex.

Characters of male: Aedeagus bulbous and somewhat asymmetrical in the typical fashion of family; operculum (subgenital plate), longer than wide (Fig. 23 ); width ~ 0.29, length ~ 0.33, rugulose in basal one third but only lightly rugose anterior to that region; central finger-like projection in center towards apex; central region raised above marginal areas; long hairs clumped near apex, other single hairs throughout.

Distribution.

Paraplea melanodera appears to be a species found only in peninsular Thailand along the west coast (Fig. 24D ). Most of the known specimens are from ponds near the beach, thus it may be an endemic species to this region of Thailand.

Type material examined.

Holotype: female, Thailand: Trang Province, Amphur Sikao, pond at Chao Mai Beach, 7°26.842'N, 99°20.647'E, 3 m, 9 I 2006, Vitheepradit and Prommi, L-907 (UMC). Paratypes (10 total): Thailand: Krabi Province: Amphur Mueang, Khlong Muang Beach, 8°02.979'N, 98°45.540'E, 13 m, 8 I 2006, Vitheepradit and Prommi, L-901 (3 paratypes UMC, 2 paratypes SHSU). Phang Nga Province: Amphur Takua Pa, Nang Tong Beach, pond, 8°38.906'N, 98°14.833'E, 16 m, 4 I 2006, Vitheepradit, Sites and Prommi, L-883 (2 paratypes UMC). Ranong Province: Laem Son National Park, pond in front of officers house, 9°36.118'N, 98°28.074'E, 6 m, 2 VIII 2005, Vitheepradit, Prommi and Simpson, L-838 (1 paratype UMC); Laem Son National Park, pond near headquarters, 9°36.247'N, 98°28.005'E, 6 m, 3 I 2006, Vitheepradit, Sites and Prommi, L-875 (1 paratype UMC); Laem Son National Park, pond near headquarters, 9°36.247'N, 98°28.002'E, 6 m, 7 VI 2006, Vitheepradit, Sites and Prommi, L-922 (1 paratype UMC).

Additional material examined.

Thailand, Krabi Province: Amphur Ko Lanta, Khlong Dao Beach pond, 07°38.662'N, 99°01.395'E, 10 m, 9 VIII 2005, Sites, Vitheepradit, Simpson and Prommi, L-865 (5 specimens UMC); Amphur Mueang, Khlong Muang Beach, 8°02.979'N, 98°45.540'E, 13 m, 8 I 2006, Vitheepradit and Prommi, L-901 (12 specimens UMC, 1 specimen SHSU). Phang Nga Province: Amphur Khura Buri, Aow Kuey Beach, pond, 9°18.005'N, 98°22.798'E, 5 m, 7 VI 2006, Sites, Vitheepradit and Prommi, L-924 (2 specimens UMC); Amphur Takua Pa, Nang Tong Beach pond, 8°38.906'N, 98°14.833'E, 16 m, 4 I 2006, Vitheepradit, Sites and Prommi, L-883 (2 specimens UMC); Amphur Takua Pa, Tumbon Bang Nai Si, Ban Bang Yai, 8°25.950'N, 98°23.192'E, 20 m, 8 VI 2006, Vitheepradit, Sites and Prommi, L-927 (2 specimens UMC); Khao Lampi-Hat Thai Mueang National Park, pond near beach, 8°28.312'N, 98°13.672'E, 1 m, 2 VI 2005, Vitheepradit and Prommi, L-824 (1 specimen UMC). Phuket Province: Amphur Thalang, Jig peat swamp, 8°08.772'N, 98°17.892'E, 23 m, 10 VI 2006, Vitheepradit, Sites and Prommi, L-942 (1 specimen UMC). Ranong Province: Laem Son National Park, pond in front of officers house, 9°36.118'N, 98°28.074'E, 6 m, 7 VI 2006, Vitheepradit, Sites and Prommi, L-923 (1 specimen UMC); Laem Son National Park, pond near headquarters, 9°36.247'N, 98°28.005'E, 6 m, 2 VIII 2005, Vitheepradit, Prommi and Simpson, L-837 (2 specimens UMC); Laem Son National Park, pond near headquarters, 9°36.247'N, 98°28.005'E, 6 m, 7 VI 2006, Vitheepradit, Sites and Prommi, L-922 (5 specimens UMC). Trang Province: Tumbon Mai Fard, Ban Klong Maeng, pond, 7°30.170'N, 99°20.541'E, 6 m, 10 I 2006, Vitheepradit and Prommi, L-908 (4 specimens UMC).

Etymology.

The specific epithet combines two Greek roots, melano - meaning black and - dero meaning the neck. Thus, the name refers the distinct dark line at the back of the head, which is distinctive of this species and a character not found in other members of the genus.

Discussion.

The distinctive character of P. melanodera sp. nov. is the dark band at the posterior margin of the head. This character is seen in all specimens of this species and is not observed in any other species of Paraplea . Paraplea melanodera sp. nov. also has a raised central portion of the subgenital plate in both sexes and is most pronounced in the mele. Other species of Paraplea in Southeast Asia do not have this character state. The coxae of P. melanodera sp. nov. are quite long. Paraplea lateromaculata sp. nov. also has long coxae, but are comparably shorter than those of P. melanodera sp. nov. Spines on the metathoracic femur are not common in Paraplea but are present in both P. melanodera sp. nov. and P. liturata . Paraplea melanodera also has spines on the prothoracic femur, including a couple that are longer than the others. Characters of the ventral keel, ovipositor, and subgenital plates also have distinct differences compared to other species of Paraplea .

In a study to determine the recovery of the lentic insect community following the Indian Ocean tsunami of 2004, Sites & Vitheepradit (2010) sampled ponds along the Thai coastline at four time intervals, including beginning five months after the tsunami, which marked the end of the dry season. Paraplea melanodera sp. nov. was collected in 11 of the 12 ponds inundated by the tsunami, including during the first sampling period, and in only two of the ten un-inundated reference ponds. The mean conductivity of all inundated ponds over all dates from which P. melanodera sp. nov. was collected was 1,714 μS, including one at 13,040 μS. Conductivity of the reference ponds further inland was <100 μS and Indian Ocean seawater was over 41,000 μS. Thus, the waterbodies in which P. melanodera sp. nov. occurred had distinctly elevated levels of salinity. It is likely that P. melanodera sp. nov. also occurs further north and south along the coastlines to Burma and Malaysia.

Distribution of Paraplea in mainland Southeast Asia.

Paraplea frontalis is one of the most widespread species of the genus and is prominent in Southeast Asia and beyond. In addition to the records reported here, P. frontalis has also been reported in other studies. Nieser (2004) stated that he had seen specimens of P. frontalis from Thailand, but these remain unpublished. The first published record of P. frontalis in Thailand did not appear until 2006 when it was reported from material collected in 1999 in Sakon Nakhon Province ( Chen et al. 2006), which do not include those eluded to by Nieser (2004) (Nico Nieser pers. comm.). Lundblad (1933) described P. quinquemaculata (now a synonym of P. frontalis ) from specimens from northern Sumatra. This region is directly west of mainland Malaysia and is considered maritime Southeast Asia, although with the short geographic distance across the Andaman Sea, it is not unexpected that these regions share species. Lundblad (1933) also reported two specimens of P. frontalis from Lake Toba, northern Sumatra and from East Java. Both of these specimens are in maritime Southeast Asia. Fernando (1961) collected P. frontalis (reported as P. quinquemaculata ) at lights from Tanjong Karang, Selangor (Malaysia), which is close to the location of the Chapman specimens reported here. Fernando and Cheng (1974) mentioned that P. frontalis (reported as P. quinquemaculata ) was collected once from a pond in Singapore but also stated that this species had never been collected in Malaya (Malaysia) even though Fernando (1961) had previously reported it from this region. Nieser and Chen (1999) reported on numerous collections of P. frontalis from Sulawesi and Sumatra (Indonesia). Esaki (1940) reported four specimens of P. frontalis from Chusan, which is an island off the southeastern coast of China. This region is not considered part of the political designation of Southeast Asia but is geographically close and this record would not be unusual with a mainland Southeast Asia species distribution. Esaki (1940) also stated that P. frontalis is widely distributed in India, Indochina, China, Java, Sumatra, Nicobar Islands and Formosa. However, no specimen data or source of that information was provided, nor did he mention any other Pleidae from this region. Esaki’s distribution could include data from several species, or it might include undocumented distribution records for P. frontalis . Distant (1910) used specimens from Calcutta and Madhupur, India to describe Plea pelopea , which is now a synonym of P. frontalis . Hafiz and Pradhan (1947) also reported P. frontalis from the nearby locality of Patnagarh, India and further north at Gait Sarovar, Bolangir, India. These areas of India share many species with a mainland Southeast Asia distribution; thus, these records might not be considered unusual. Benzie (1989) found P. frontalis from waterholes in Yala National Park in southeastern Sri Lanka.

It is uncertain what factors influence the distribution of P. frontalis . The limited number of collections that represent our knowledge of this species suggest that it is most common in mainland Southeast Asia, but its distribution extends to the north into eastern Asia in China and Taiwan, west to India and Sri Lanka, and south to maritime Southeast Asia on islands of Indonesia. This paper represents the only data where an area was more thoroughly collected, although even this effort provides fewer than 500 specimens. When these collections are plotted on a distribution map (Fig. 24A ), there is no perceptible indication of reasons for this distribution. In fact, with more collections, P. frontalis may be found throughout nearly all provinces of Thailand.

Another factor to consider is that what is reported as P. frontalis could be a species complex. This would not pertain to the distribution shown in Fig. 24A but could be a factor in reports in other areas of its distribution. There are noted morphological differences among specimens of P. frontalis from different parts of its range, including size differences, some differences in markings and other minor morphological variation. More study and many more specimens are needed to sort out this situation, probably including modern molecular comparisons of specimens from these various regions. Until this future study, P. frontalis will be considered a variable species with a wide distribution.

Paraplea liturata is widely distributed in Thailand and some predict that it could have the largest distribution of any species in the genus ( Lundblad 1933, Fernando 1961). Its distribution in Thailand (Fig. 24C ) does not appear as extensive of that of P. frontalis but it is a common inhabitant within a wide geographic distribution. Fernando and Cheng (1974) collected P. liturata at several locations in Malaysia and recorded it as being "fairly common" in this region. Nieser and Chen (1999) likewise found it in several locations in Indonesia as well as documenting the species in the Philippines.

Paraplea liturata does not appear to be restricted to any general habitat type or biogeographical region. Chen et al. (2006) stated that it was "common throughout Thailand in vegetation rich stagnant waters." The present study also indicates that the species occurs in ponds and slow-moving streams, both containing aquatic vegetation. Anderson and Weir (2004) reported P. liturata from Western Australia and the Australian Northern Territory, areas biogeographically quite different from Thailand and Malaysia, but did not comment on the specifics of the collection sites.

The distribution of P. lateromaculata sp. nov. (Fig. 24B ) is very similar to that of P. liturata (Fig. 24C ) in Thailand, including collection sites in common between these species. Both of these species were common in the peninsular region of Thailand.

The documented distribution of P. melanodera sp. nov. includes only the central part of peninsular Thailand (Fig. 24D ). Even more restrictive is that it was collected only from small ponds near beaches along the coastline. The apparent halophilic nature of P. melanodera sp. nov. is well-documented because all specimens were collecting during the tsunami study of Sites & Vitheepradit (2010). The other three species of Paraplea also were collected during the study; however, these were mostly from un-inundated reference ponds. More specifically, P. lateromaculata sp. nov. was collected in two reference ponds, including during all four sampling periods. Paraplea liturata was collected in all reference ponds over all sampling periods as well as a single individual from an inundated pond on the first sampling date, which we consider an adventitious occurrence. Paraplea frontalis was collected in two inundated ponds with elevated levels of salinity on the last sampling date, which was 17 months after the tsunami. Because eight and 28 specimens were collected in those two ponds, its occurrence was not adventitious; thus, P. frontalis appears to have a tolerance for salinity, but is not as adept at dispersing as is P. melanodera sp. nov.

Figures

Figure 18. Paraplea melanodera sp. nov. A female in lateral view with typical coloration. B dorsal view of a light colored morph that shows dark banding and typical minimum amount of honeycombing. C frontal view of specimens in B. D female showing a lighter colored lateral view without dark hemelytral bands.

Figure 21. Ovipositor of Paraplea melanodera sp. nov. Scale bar: 0.05 mm.

Figure 24. Distribution records in Thailand of A Paraplea frontalis B P. lateromaculata sp. nov., C P. liturata D P. melanodera sp. nov.

Figure 19, 20. Paraplea melanodera sp. nov. 19 prothoracic leg at the top, mesothoracic leg in the middle and metathoracic leg below. 20 profile of the ventral keel with the anterior end (thoracic) to the top and ventral to the left.

Figures 22, 23. Genital plates of Paraplea melanodera sp. nov.: 22 female, 23 mele. Scale bar: 0.1 mm.