Genus Rhabdoblattella Anisyutkin, 2000

Type species: Rhabdoblattella cambodiensis Anisyutkin, 2000. By original designation.

Diagnosis. The genus Rhabdoblattella is characterized by a unique complex of features: sexual dimorphism poorly marked; tegmina and wings completely developed or slightly abbreviated (as in R. alexeevi sp.nov. — Fig. 4A); hind metatarsus longer than other segments combined, with the small apical euplantula along its lower margin, all segments of metatarsus with 2 more or less equal rows of spines along its lower margin; all euplantulae without spinules, partly bordered with rows of spines; claws symmetrical and very weakly serrated (visible at a large magnification); hypandrium asymmetrical, its caudal margin rounded and projected caudally, with a distinct median tooth directed upward (Figs. 5 F, G, 6H, I, m.t.); right phallomere of the male genitalia with the caudal part of sclerite R1T (Figs. 5 H, I, 6J, 11K, c.p.R1T) being separated from the cranial part R1T (Figs. 5 H, I, 6J, 11K, cr.p.R1T), R3 triactinal with more or less developed branches (Figs. 5 I, 6J, 11K), R2 fused with R5, R5 wide, platelike (Figs. 5 H, 6J, 11K).

Notes. In our opinion, the presence of a median tooth on the caudal margin of hypandrium and the structure of right phallomere described above can be considered the autapomorhies of the genus Rhabdoblattella. Other aforementioned characters that were listed in the original description (Anisyutkin 2000) are most likely to be plesiomorphic ones, as compared with other genera of the Epilamprinae.

A somewhat similar structure of the right phallomere can be observed in representatives of the genus Africalolampra Roth, 1995. The structure of the male genitalia in the type species, A. ehrmanni Roth, 1995, was briefly described by Roth (1995). Yet, the right phallomeres of A. erubescens (Gerstaecker, 1883) and A. punctipennis (Saussure, 1895) are generally similar to those of Rhabdoblattella species (compare Figs. 5 H, I, 6J and 11K and Figs. 8, 9, 29 30 in Anisyutkin 2016).

It is possible that the plate-like sclerite of the right phallomere of A. erubescens and A. punctipennis (see Figs. 8, 9, 29 30, pl.s. in Anisyutkin 2016) is homologous to the caudal part of sclerite R1T described in the present paper.

The genus Rhabdoblattella originally included five species from Cambodia (the type species), Vietnam, Thailand and Burma (Anisyutkin 2000): R. cambodiensis Anisyutkin, 2000, R. vietnamensis Anisyutkin, 2000, R. delicata Anisyutkin, 2000, R. annandalei (Shelford, 1909) and, probably, R. kabakovi (Bey-Bienko, 1969). Later, Rhabdoblatta annamensis (Hanitsch, 1927) was transferred to the genus Rhabdoblattella by Anisyutkin (2009). The male of R. kabakovi still remains unknown, so the generic assignment of this species is doubtful.

The representatives of Rhabdoblattella from South India and Sri Lanka described below (R. alexeevi sp.nov. and R. euptera sp.nov.) differ from the previously known SE Asian species by the presence of the well developed glands on the abdominal tergites (Figs. 5 C, 6C, D). Additionally, R. alexeevi sp.nov. differs from all other congeners in having the slightly abbreviated tegmina and wings (Fig. 4A), whereas R. euptera sp.nov. can readily be distinguished from other congeners by the absence of the apical part of sclerite L2D (Fig. 6 K, L). It should be noted that the abdominal tergal glands of R. alexeevi sp.nov. and R. euptera sp.nov. are located on different segments (compare Figs. 5 C and 6C, D), which makes their homologation controversial.

The abdominal tergal glands in males play an important role in the sexual behavior of cockroaches (Bell et al. 2007, Roth 1969, Roth & Willis 1954). Consequently, the presence of these structures could indicate significant behavioural differences between new species (R. alexeevi sp.nov. and R. euptera sp.nov.) and their congeners. On the other hand, the functionally similar tergal glands in Orthoptera can vary within the same genus (for instance, in Landrevinae—see Gorochov 2016). The shortening of tegmina and wings in R. alexeevi sp.nov. obviously demonstrates a significant shift in its lifestyle as well. Unfortunately, at the present time it is impossible to comment on a functional significance of the apical part of sclerite L2D, which is absent from R. euptera sp.nov.

Taking into consideration that the available material is scanty and both species seem to differ morphologically from each other, it is better to postpone a formal description of a new genus/subgenus for R. alexeevi sp.nov. and R. euptera sp.nov.