Nerthra occidua Todd, 1959

Nieser, Nico, Chen, Ping-ping & Caspers, Max, 2024, Taxonomic notes on toad bug genus Nerthra (Hemiptera: Heteroptera: Gelastocoridae) with description of a new species from Bonaire and Curaçao, Acta Entomologica Musei Nationalis Pragae 64 (1), pp. 33-46 : 42

Nerthra occidua Todd, 1959

( Figs 17 , 31–37 , 39 )

Nerthra occidua Todd, 1959: 71 (original description).

Nerthra lurida Todd, 1959: 72 (original description), syn. nov.

Type material examined. Nerthra lurida : HOLOTYPE: ♀, INDONESIA: SULAWESI SELATAN ( Fig. 39 ): Rantepao, Nanggala , 900 m, vii.1937, leg. Drescher ( RMNH).

Additional material examined. INDONESIA: SULAWESI TENGAH: Lore Lindu NP, Sopu River Pools, 930 m a.s.l., 6.xii.1985, leg. J. Krikken & J. van Tol, 1 ♀, det. P. Lindskog (identified by comparing with type) ( RMNH); Lore Lindu NP, Sopu River Pools, 930 m a.s.l., 6.xii.1985, leg. J. Krikken & J. van Tol, 2 ♀♀ ( RMNH); Lore Lidu N.P., Dongi Dongi shelter, 940 m a.s.l., 4.‒8.xii.1985, multistratified evergreen forest, 2 fish traps, leg. J. Krikken, 3 ♀♀ ( NCTN); same, garage, 950 m a.s.l., 4.‒9. xii.1985, multistratified evergreen forest, 4 dung traps, leg. J. Krikken, 4 33 7 ♀♀, 1 L (instar 5) (2 33 2 ♀♀ NCTN, 2 33 5 ♀♀ RMNH); Lore Lindu NP Dongi Dongi shelter, 940 m a.s.l., 4.‒8.xii.1985, multistratified evergreen forest, 2 human excr[ement] traps, leg. J. Krikken, 1 3 1 ♀, 3 L (instar 4) ( RMNH); Lore Lindu NP, Danau Tambing forest, 1600 m a.s.l., 5.‒09.xii.1985, multistratified evergreen forest, 4 human excr[ement] traps, leg. J. Krikken, 1 ♀ ( RMNH).

Discussion ( Fig. 39 ). TODD (1959) described two species in the same paper, namely N. occidua (holotype male, deposited in Museum für Naturkunde, Berlin) and N. lurida (holotype female, deposited in RMNH), and mentioned a number of small differences between them. Both the species were collected from Sulawesi but each of them was based on an unique specimen of different sex, therefore comparison of male genitalia was not possible. Nerthra occidua was distinguished from N. lurida by a wider head (equal to combined length of pronotum and scutellum), the front of the head rounded, scutellum moderate with median and basal portions depressed, and the pronotum and abdomen wider. According to the drawing given by TODD (1959: 63, figs 14–15), little difference can be seen except that N. lurida is very slightly broader.

After the work of Todd, additional gelastocorids were collected in Sulawesi by Dr. J. Krikken and other colleagues of RMNH during the Project Wallace in 1985. It is interesting to note that the specimens were collected in pitfalls baited with excrement or rotting fish as collateral catch of research on dung beetles. There are other records of species of Nerthra found in cow dung: the Neotropical N. manni Todd, 1955 ( LAUCK & WHEATCROFT 1958) and N. raptoria , specimens in RMNH (see above). This does not necessarily imply that these species eat dung, but more likely the bugs are able to find prey near this kind of smell. We have compared the later samples with the holotype of N. lurida . Running the key of TODD (1959: 62), the males of this series from Sulawesi ( Figs 30–32 ) can be identified as N. occidua by the shape of paramere ( TODD 1959: 69, Fig. 45). However, the front of the head ( Figs 31–34 ) is flat and its width is less than the combined length of the pronotum and the scutellum (4.5 / 5.0), which would agree with N. lurida according to TODD (1959). In some females, the front of the head is slightly convex ( Figs 31–34 ), but in most, as in N. occidua , the width of head is less than the length of the pronotum and the scutellum combined (4.7 / 5.1) as in N. lurida . The scutellum itself is not elevated but all three tumescences are strongly elevated in both males and females. Therefore, we conclude that N. occidua and N. lurida refer to the same species. We choose N. occidua as the valid name because it was described on a male, and N. lurida becomes its junior subjective synonym.

Figures

Figs 15–18. Nerthra spp., apex of paramere, ventral view: 15 – N. americana (Montandon, 1905); 16 – N. buenoi Todd, 1955; 17 – N. occidua Todd, 1959; 18 – N. raptoria (Fabricius, 1803).

Figs 31–34. Nerthra occidua Todd, 1959. 31–33 – male, habitus (31 – dorsal view, cleaned; 32 – ventral view, cleaned; 33 – dorsal view, before cleaning). 34 – female, habitus (ventral view, cleaned).

Figs 35–37. Nerthra occidua Todd, 1959. 35–36 – female, habitus dorsal view (35 – before cleaning, 36 – cleaned). 37 – apex of paramere (ventral view).

Figs 38–39. Distribution of treated Nerthra species: 38 – N. americana (Montandon, 1905), N. buenoi Todd, 1955 and N. papaceki sp. nov.; 39 – N. occidua Todd, 1959.

Fig. 30. Nerthra papaceki sp. nov., paramere and pygophore (a – ventral view, b – dorsal view).