Adelphocorisella Miyamoto & Yasunaga, 1993

Yasunaga, Tomohide, Shishido, Takayuki & Yamada, Kazutaka, 2016, Two new species of the mirine plant bug genus Adelphocorisella (Insecta: Heteroptera: Miridae: Mirinae: Mirini) from central Thailand, Raffles Bulletin of Zoology 64, pp. 250-256 : 250-254

Genus Adelphocorisella Miyamoto & Yasunaga

Adelphocorisella Miyamoto & Yasunaga, 1993: 47 (n. gen.), type species by original designation: A. lespedezae Miyamoto & Yasunaga, 1993: 48 ; Schuh, 1995: 695 (cat.); Kerzhner & Josifov, 1999: 59 (cat.); Yasunaga et al., 2001: 211 (diag.).

Diagnosis. Distinguished from other mirine genera, in particular Adelphocoris Reuter , Creontiades Distant , Orientomiris Yasunaga , and Phytocoris Fallén , by following combination of characters: Moderate size (4−6 mm in total length); mostly brown-mottled color pattern ( Fig. 2 ); elongate body shape ( Fig. 1 ); slightly to moderately oblique head; two types of vestiture (simple brown semierect setae and reclining silvery setae) usually present on dorsum; antennal segment I shorter than width of head across eyes; antennal segments II−IV uniformly yellowish, linear with almost equal diameter; rostrum long, usually exceeding apex of metacoxa; male pygophore lacking paired, conical processes near paramere insertions; wide membranous endosoma always with a distinct spiculum as well as a set of gonoporal sclerites ( Figs. 3 & 4 , sclerite ‘a’) and secondarily extending sclerite ‘b’, and with a more or less (usually basally) sclerotized lateral lobe.

Distribution. Australia (Queensland), Japan (Honshu, Kyushu, Ryukyu Islands), Korea, Thailand; several unidentified species currently represented only by adult females are known in Indonesia and the Philippines.

Biology. Two Japanese species, A. lespedezae Miyamoto & Yasunaga and A. insulana Miyamoto & Yasunaga , are known to inhabit on Lespedeza spp. and/or Pueraria spp. ( Fabaceae ), on which the immature forms were found ( Yasunaga et al., 2001). No biological information is available for tropical species.

Discussion. Adelphocorisella can be distinguished from other related genera by the above characters. As mentioned by Yasunaga & Schwartz (2015), the present genus, and Adelphocoris Reuter , Creontiades Distant and Phytocoris Fallén are likely to have derived from the same lineage, based on the similar body shape and the assumed homology of the endosomal sclerites. The endosoma (almost wholly membranous and lacking any noticeable sclerites) in Creontiades seems to represent the most primitive character status within these genera ( Yasunaga, 1997). In Adelphocorisella , a spiculum and sclerite ‘b’ [= ‘sclerite B’ sensu Malipatil & Chérot (2002)] are hypothesized to replace the comb-shaped sclerite in Adelphocoris and Phytocoris ( Yasunaga, 1990; Yasunaga & Schwartz, 2015), and the hook-shaped sclerite in Adelphocoris ( Yasunaga, 1990) respectively. The gonoporal sclerite [ Fig. 3 & 4 , sclerite ‘a’ = ‘sclerite A’ sensu Malipatil & Chérot (2002)] is situated on the secondary gonopore between two major membranous lobes and shared by all of these genera and many other mirines. To demonstrate more reliable phylogenetic relationships between such related genera, the acquisition of DNA sequence data would be necessary.

The present discovery of the two new species from Indochina expands the known distribution of Adelphocorisella , now ranging from the eastern Palearctic and Oriental to Australian regions across Wallacea. However, quite a few species previously described under Adelphocoris or Phytocoris from the Oriental tropics (cf., Poppius, 1915) most likely belong to Adelphocorisella ( Malipatil & Chérot, 2002, Yasunaga & Schwartz, 2015), because most members of the two former genera are considered to be temperate zone inhabitants.

Of the two new species described below, Adelphocorisella sarika ( Fig. 1A, B ) exhibits a typical facies of the genus and is unequivocally related to A. insulana and A. lespedezae ( Fig. 1C ). On the other hand, we at first thought our new taxon, A. adelphocoroides , was a member of Adelphocoris , because of greater similarity in external appearance ( Fig. 1 D−F vs. G & H for Adelphocoris triannulatus ). But our investigation of the male genitalia doubtlessly suggest that this new species belongs to Adelphocorisella ( Fig. 3 ). In Adelphocoris , the endosoma is cubically and broadly sclerotized and, without exception, bears comb- and hook-shaped spiculi; externally ( Fig. 1G & H ), the body is larger and lacks mottled color pattern, the head is vertical, and the labium does not exceed much beyond the metacoxa ( Yasunaga, 1990).

Figures

Fig 4. Male genitalia of Adelphocorisella sarika, holotype.

Fig. 2. Habitus images of dried specimens of Adelphocorisella spp. A, A. adelphocoroides, holotype male; B, A. sarika; C, dittos, lateral view.

Fig. 1. Habitus images of live individuals. A, Adelphocorisella sarika, male from Nakhon Nayok; B, ditto, from Nakhon Ratchasima; C, A. lespedezae, male from Nagasaki, Japan; D−F, A. adelphocoroides, holotype male; G, Adelphocoris triannulatus (Stål), male from Nagasaki; H, ditto, female from Nagasaki.

Fig. 3. Male genitalia of Adelphocorisella adelphocoroides, holotype.