Paraplea, Esaki & Chna, 1928

Cook, Jerry L., 2021, Review of the Paraplea Esaki & China (Hemiptera: Heteroptera: Nepomorpha Pleidae) of Australia, with description of a new species, Zootaxa 4985 (1), pp. 81-90 : 87-90

Synopsis of Paraplea of Australia

Knowledge of the distribution of Australian Pleidae is almost certainly incomplete but what we know allows for some conclusions about these species. Paraplea brunni is known from all Australian states and territories except Victoria and the Australian Capital Territory. However, there is no reason to expect that P. brunni would be absent from these areas. Paraplea brunni has also been reported from New Guinea but is otherwise known from no other regions. Paraplea liturata does not appear to be a common species in Australia but this widespread species has been found in northern regions of Australia, in the Northern Territory and Western Australia. Paraplea brunni is also found in some of the same regions where P. liturata occurs in Australia. Paraplea halei appears to be restricted to southeastern Australia. It has been collected in Victoria, Tasmania, southern New South Wales and the southeast region of South Australia. These same areas also coincide with a portion of the distribution of P. brunni . Paraplea bifurcata n. sp. is documented here from the type locality in Northern Australia but this is most likely the specimens designated as Paraplea sp. nov. ANIC 1 by Weir (2017), which would give it a wider distribution within the Northern Territory. This region is also closely associated with the known distribution of P. brunni .

The four species of Pleidae that occur in Australia are all in the genus Paraplea , but their distributions and morphology are clearly different. Two species, P. brunni and P. liturata , are widely distributed species, while P. halei and P. bifurcata n. sp. appear to have somewhat more restricted distributions. However, P. bifurcata probably has a much wider distribution that also includes Western Australia and Queensland (Tom Weir communication). Morphologically, P. liturata , is distinctly different from all other Australian species, being smaller and more globular in body shape. Paraplea bifurcata n. sp. and P. brunni share a similar body shape, which is more elongated and tapered posteriorly in dorsal view. Paraplea halei also has an elongated body shape, although not as tapered posteriorly ( Fig. 10 ).

Published descriptions of the species of Pleidae occurring in Australia provide sufficient information for comparisons of these species. Lundblad (1933) provided a re-description of P. brunni and a description of P. halei that allow for the diagnosis of these species. Lansbury & Lake (2002) also provided characters to separate P. halei and P. brunni . Paraplea liturata was poorly described by Fieber (1844) but subsequent treatments of this species by Lundblad (1933), Andersen & Weir (2004) and Cook et al. (2020) provide sufficient diagnostic characters to define this species. The description above of P. bifurcata completes the information needed to separate the Australian species.

The dorsal aspect of the four species known to occur in Australia allows for easy identification of these species ( Fig. 10 ). Paraplea liturata is the only species with dark maculations on the pronotum, however Cook et al. (2020) found that about nine percent of specimens from Thailand did not have the full complement of five spots and less than one percent had no spots. Still, having any dark maculations of the pronotum would suggest it is not one of the other three species. Paraplea brunni and P. halei are the only Australian species without punctures in the center of the pronotum. However, P. brunni has hemelytral punctures that are clearly marked by dark maculations. Similar dark punctures of the hemelytra also occur in P. bifurcata n. sp., but the scutellum is much different between these species. Paraplea bifurcata n. sp. has a rough textured scutellum where punctures are not visible, while the scutellum of P. brunni is relatively smooth, which only a few large easily seen punctures. Paraplea halei is easily separated from all other Australian species by its lack of a claval suture. The most recognizable distinguishing character of P. bifurcata n. sp. in dorsal view is the above-mentioned pronotal morphology with many small, densely packed punctures and a scutellum that is somewhat rugose and lacks distinct punctures.

While color characteristics are not sufficient to separate all species of Paraplea , the Australian species can often quickly be identified by consistent color differences ( Fig. 11 ). Two species, P. brunni and P. bifurcata n. sp., have punctures on the hemelytra surrounded by dark maculations that are never found on P. halei or P. liturata . Paraplea bifurcata n. sp. has a body that is not shiny and is a uniform light tan color, except for the maculation associated with hemelytral punctures. Paraplea brunni has a shiny body with areas of light and dark, and distinct honeycomb patterns. Paraplea halei has a consistent brown base color with tan honeycombing throughout much of the lateral and dorsal aspects. Besides the pronotal maculations discussed above, P. liturata usually has light and dark bands on the lateral portion of the hemelytra.

All of the Australian Paraplea have relative modern descriptions that will allow for their identification, although there are important taxonomic characters that are still missing from some of these descriptions. The most important of these has been our lack of knowledge of the ovipositor in P. brunni and P. halei . Lundblad (1933) included the first description of the ovipositor of P. liturata based on specimens from Java. Lundblad’s figure of the ovipositor is nearly identical to the ovipositor from Thailand shown by Cook et al. (2020). The ovipositor in P. liturata is distinctive in having four long ventral hairs as well as a uniform series of apical, primary, and secondary teeth of the gonapophysis of the ovipositor. The ovipositor of P. brunni was not included in the description by Lundblad (1933) but is now shown in Figure 12 , drawn from specimens examined during the present study. This ovipositor is similar to that of P. bifurcata n. sp. but is both larger and has fewer teeth. The ovipositor of P. halei remains unknown. Its characters were not in included in the original description by Lundblad (1933) and the ovipositor was not visible in the two specimens available for the present study.

Key to the species Paraplea of Australia

This key can be used to identify both male and female specimens of Paraplea from Australia. Additional characters from descriptions by Lundblad (1933), Lansbury & Lake (2002), Anderson & Weir (2004), Cook et al. 2020, and the present paper can be used to confirm identifications.

1. Abdominal keel bifurcated ( Fig. 5 ) (Northern Territory)......................................... P. bifurcata n. sp.

- Abdominal keel ending in a blunt point................................................................... 2

2. Without claval suture (southeastern Australia)......................................................... P. halei

- With claval suture.................................................................................... 3

3. Pronotum with punctures throughout, usually with five dark spots on pronotum, hemelytra usually with banding but without dark punctures (Northern Territory and Western Australia as well as widespread in regions outside Australia)..... P. liturata

- Pronotum without punctures medially, without dark spots on pronotum but pronotum may be dark with light honeycombing, hemelytra without banding but with dark spots at the center of each puncture (widespread within Australia only)... P. brunni

Figures

FIGURE 10. Dorsal view of species of Paraplea known from Australia (image of P. liturata in this plate is from a specimen from Thailand).

FIGURE 11. Lateral view of species of Paraplea known from Australia (image of P. liturata in this plate is from a specimen from Thailand).

FIGURE 12. First gonapophysis of the ovipositor of Paraplea brunni. Teeth with numbers (1–6) are apical teeth; ventral teeth are designated with a V and their positional number; those with P, S, and T represent primary, secondary and tertiary teeth respectively. Scale bar = 0.1.

FIGURES 5 & 6. Paraplea bifurcata n. sp. (5) ventral view of abdomen with bifurcated keel on first four abdominal segments, (6) profile of keel with prothoracic segment at top and fourth abdominal segment at bottom.