Stenolemus alikakay Rédei & Tsai, 2010

Ishikawa, Tadashi & Naka, Takeru, 2016, The assassin bug genera Nagustoides and Stenolemus (Hemiptera: Heteroptera: Reduviidae) newly recorded from Japan, Zootaxa 4161 (4), pp. 593-600 : 598-599

Stenolemus alikakay Rédei & Tsai, 2010

( Figs. 17–30 )

Stenolemus alikakay Rédei & Tsai, 2010: 28 (new species) Among the Oriental species of the genus Stenolemus , this thread-legged assassin bug is recognized by the following combination of character states: posterior lobe of head with a pair of wide, blunt tubercles dorsally ( Figs. 21, 25 ); pronotum not darkened on basal part ( Fig. 20 ); petiole of pronotum relatively short, approximately twice as long as its width at middle in dorsal view ( Figs. 17–18 , 20–21 ); posterior pronotal lobe with a single carina along meson and a pair of conical projections on disc ( Figs. 20–21 ); profemur with four brown annulations ( Fig. 22 ); middle and hind legs lacking pigmented tufts of setae ( Figs. 23–24 ); mesofemur with three brown annulations ( Fig. 23 ); metafemur with four brown annulations ( Fig. 24 ); and a peculiar color pattern of the forewings ( Fig. 19 ). Body length (from apex of head to apex of abdomen) 8.8–11.6 mm. A detailed description of this species was provided by Rédei & Tsai (2010).

Specimens examined (n=2). JAPAN: the Ryukyu Islands—Ôhama, Ishigaki-jima Is.: 1 ♀ ( Figs. 17–19 , 22–24 ), 4.ix.2012, T. Higa ; 1 ♀ ( Figs. 20–21, 25–27 ), 18.vi.2013, T. Naka.

Distribution. Japan (the Ryukyu Islands: Ishigaki-jima Is.); Taiwan.

Remarks. Among the reduviids of Japan, Stenolemus alikakay is at first sight similar in general habitus, especially in its hairy body and appendages, to the thread-legged assassin bug Myiophanes tipulina Reuter, 1881 . However, S. alikakay can be easily distinguished from M. tipulina by its much smaller body size (approximately 10 mm vs. 16 mm), the presence of the petiole in the pronotum ( Figs. 17–18 , 20–21 ) (vs. absence), and forewings with discal and basal cells ( Fig. 19 ) (vs. discal cell only).

Rédei & Tsai (2010) observed a living S. alikakay on a spider web (spiders missing) built on a tree trunk, walking very slowly and imitating a piece of debris or dried leaf swinging lightly in the breeze. Each of the two Japanese specimens examined here was found on the mossy and lichened trunk of a large tree, Castanopsis sieboldii (Makino) Hatus (Fagaceae) , in a well-preserved forest on Ishigaki-jima Island ( Figs. 27–30 ). When found, they were slowly swaying back and forth on the trunks while maintaining their position.

Figures

FIGURES 17 – 19. Stenolemus alikakay from Japan, female, dorsal (17) and lateral (18) views, and left forewing (19). Scale bars: 3 mm for Figs. 17 – 18, 1 mm for Fig. 19.

FIGURES 20 – 26. Stenolemus alikakay from Japan. 20 – 21, Head and pronotum, dorsal (20) and lateral (21) views; 22 – 24, femora of fore (22), middle (23), and hind (24) legs; 25, head, lateral view; 26, protarsus. Scale bars: 1 mm for Figs. 20 – 25, 0. 5 mm for Fig. 26.

FIGURES 27 – 30. Stenolemus alikakay from Japan and its habitat. 27, A living individual; 28, mossy and lichened trunk of Castanopsis sieboldii on which the individual of S. alikakay was found; 29 – 30, habitat of S. alikakay on Ishigaki-jima Island.