Aleochara (Aleochara) yaeyamensis Yamamoto & Maruyama, 2016, n. sp.

Aleochara (Aleochara) yaeyamensis n. sp.

(Figs 7, 16, 25, 34, 42, 86–92, 120, 126)

Type material. Holotype: male, Kanpireno-taki Fall, Taketomi-chô (Iriomote-jima Is.), Okinawa-ken, JAPAN, 28.iii.2014, S. Yamamoto leg., from chicken carrion trap in evergreen broad-leaved forests (Fig. 120) (KUM).

Paratypes. JAPAN: Okinawa-ken: 7 unsexed, Yonebaru, Ishigaki-shi (Ishigaki-jima Is.), 24.iii–1.iv.2007, T. Watanabe leg. (cTW); 2 unsexed, Mt. Omoto-dake, Ishigaki-shi (Ishigaki-jima Is.), 17.iv.1963, H. Nomura leg. (cYH); 2 unsexed, Mt. Omoto-dake, Ishigaki-shi (Ishigaki-jima Is.), 23.iii.1975, H. Ôishi leg. (KUM); 1 female, Mt. Omoto-dake, Ishigaki-shi (Ishigaki-jima Is.), 9.vi.1977, K. Kawada leg. (KUM); 1 unsexed, Mt. Omoto-dake, Ishigaki-shi (Ishigaki-jima Is.), 6.iv.1998, T. Ueo leg. (KUM); 1 male, Mt. Omoto-dake (trailhead), Ishigaki-shi (Ishigaki-jima Is.), 30.iv.2007, K. Haga leg., from human feces (KUM); 2 females, 5 unsexed, Mt. Omoto-dake, Ishigaki-shi (Ishigaki-jima Is.), 2–5.ii.2009, H. Ono leg., from baited trap (KUM); 1 unsexed, Mt. Omoto-dake, Ishigaki-shi (Ishigaki-jima Is.), 14.iv.2014, S. Yamamoto leg. (KUM); 1 unsexed, Mt. Omoto-dake, Ishigaki-shi (Ishigaki-jima Is.), 15.iv.2014, S. Yamamoto leg. (KUM); 4 males, 33 unsexed, Mt. Omoto-dake, Ishigaki-shi (Ishigaki-jima Is.), 17.iv.2014, S. Yamamoto leg., from chicken carrion baited trap (KUM); 10 unsexed, Takedarindô forestry road, Ishigaki-shi (Ishigaki-jima Is.), 24.iii–1.iv.2007, T. Watanabe leg. (cTW); 1 female, Shiramizu, Ishigaki-shi (Ishigaki-jima Is.), 12.ix.1993, M. Ôhara leg. (KUM); 1 female, Mt. Banna-dake, Ishigaki-shi (Ishigaki-jima Is.), 23.iii.2003, M. Hanatsuka leg. (KUM); 1 female, Mt. Banna-dake, Ishigaki-shi (Ishigaki-jima Is.), 23.iv.2003, M. Hanatsuka leg. (KUM); 2 males, 2 females, 6 unsexed, Mt. Yarabu-dake, Ishigaki-shi (Ishigakijima Is.), 11.iv.2009, S. Yamamoto leg. (KUM); 2 unsexed, Mt. Yarabu-dake, Ishigaki-shi (Ishigaki-jima Is.), 14.iv.2014, S. Yamamoto leg., from chicken carrion baited trap (KUM); 1 unsexed, Mt. Yarabu-dake, Ishigaki-shi (Ishigaki-jima Is.), 16.iv.2014, S. Yamamoto leg. (KUM); 3 males, 2 females, 20 unsexed, Mt. Yarabu-dake, Ishigaki-shi (Ishigaki-jima Is.), 16.iv.2014, S. Yamamoto leg., from chicken carrion baited trap (KUM); 3 males, 2 females, 22 unsexed (2 specimens preserved in 99.5% EtOH for DNA sequencing), Mt. Yarabu-dake, Ishigaki-shi (Ishigaki-jima Is.), 17.iv.2014, S. Yamamoto leg., from chicken carrion baited trap (KUM); 1 unsexed, Nebaruutaki, near Yoshiwara, Ishigaki-shi (Ishigaki-jima Is.), 4.v.1998, K. Toyoda leg., from human feces (KUM); 1 unsexed, Ishigaki-jima Is., Ishigaki-shi, 2.viii.1962, Y. Hama leg. (cYH); 1 unsexed, Ishigaki-jima Is., Ishigaki-shi, 19.viii.1997, K. Takahashi leg. (KUM); 2 unsexed, Ishigaki-jima Is., Ishigaki-shi, xi.1998 – xii.1999, K. Takahashi leg. (KUM); 1 male, 2 females, 6 unsexed (2 specimens preserved in 99.5% EtOH for DNA sequencing), Kanpireno-taki Fall, Taketomi-chô (Iriomote-jima Is.), 28.iii.2014, S. Yamamoto leg., from chicken carrion trap (same data as holotype) (KUM); 2 males, 1 female, 25 unsexed, Kanpireno-taki Fall, Taketomi-chô (Iriomote-jima Is.), 29.iii.2014, S. Yamamoto leg., from chicken carrion trap (completely same place as holotype) (KUM); 2 unsexed, Komi, Taketomi-chô (Iriomote-jima Is.), 13.ii.1998, M. Kimura leg. (KUM); 1 male, 1 female, 4 unsexed, Komi (Aira-gawa River), Taketomi-chô (Iriomote-jima Is.), 28.iv–5.v.1999, S. Hori leg., from flight interception trap (KUM); 3 males, 1 female, 10 unsexed, Komi, Taketomi-chô (Iriomote-jima Is.), 3–5.iv.2009, S. Yamamoto leg., from flight interception trap (KUM); 3 unsexed, Komi, Taketomi-chô (Iriomote-jima Is.), 20–22.iv.2014, S. Yamamoto leg., from flight interception trap (KUM); 1 male, 1 female, Komi, Taketomi-chô (Iriomote-jima Is.), 22.iv.2014, S. Yamamoto leg., from chicken carrion trap (KUM); 1 unsexed, Aira-gawa River, Taketomi-chô (Iriomote-jima Is.), 27–31.iii.2007, T. Watanabe leg. (cTW); 2 unsexed, Aira-gawa River, Taketomi-chô (Iriomotejima Is.), 27–31.iii.2007, T. Watanabe leg., from flight interception trap (cTW); 1 unsexed, Ôtomi, Taketomi-chô (Iriomote-jima Is.), 31.iii.2007, T. Watanabe leg. (cTW).

Diagnosis. This new species resembles A. parens including male and female genitalia, but can be discriminated from it as following characters: head with punctation rather dense, deep, and prominent; median lobe of male aedeagus with apical lobe moderately hook-like shaped in lateral view, apical lobe abruptly much thinner, forming sharply pointed apex in parameral view; head of female spermatheca rather truncate at apex, with a long chitinized portion of spermathecal stem, almost 1.5 times as long as spermathecal head and neck combined; endemic to the Yaeyama-shotô Islands (the Ryûkyûs, southwestern Japan) where no specimen of A. parens was found. This species can be discriminated from the sympatric species, A. postica, by densely and evenly punctured head and by male and female genital organs.

Description. Measurements (in mm, n = 20): BL = 5.52 (3.08–6.96); HL = 0.82 (0.60–0.93); HW = 0.92 (0.73–1.03); PL = 1.06 (0.79–1.30); PW = 1.46 (1.11–1.81); EL = 0.82 (0.65–1.02); EW = 1.70 (1.13–2.11).

Body (Figs 7, 16): fusiform, robust, medium to relatively large in size; dorsal surface weakly glossy and pubescent, without any types of micro-reticulation, moderately punctured. Color (Figs 7, 16): usually uniformly brownish brown to blackish brown, but elytra variable in color pattern, generally pale brown to dark brown uniformly (sometimes infuscate laterally and basally to form somewhat indistinct darken maculations); antennae with antennomeres I–III yellowish brown to dark reddish brown, antennomere IV much darker, antennomeres V– XI slightly darker than those of I–III but covered with minute whitish setae densely; mouth parts and legs yellowish brown to brownish brown; pubescence yellowish brown.

Head (Fig. 25): semicircular, as long as width (HW/HL = 1.12, n = 20), widest at posterior part of eyes; setae on vertex rather dense but inconspicuous, directed anteriomedially; punctation medium in size unevenly scattered densely, vertex with lack of punctation at middle but small to very small in size, surrounded by dense punctation. Eyes: medium in length, occupying approximately half length of head, slightly protruding laterally.

Antennae (Fig. 42): short, moderately shorter than head and pronotum combined; thick, setose, with antennomere IV clearly transverse, antennomeres V to X strongly transverse in approximately same width each (very slightly but widest at antennomere VI); antennomere XI symmetrical, obtusely rounded at apex; approximate relative length of antennomeres from base to apex: 21 (including base): 8: 9: 4.5: 5: 5: 5: 5: 5: 6: 15.

Pronotum (Fig. 7): transversely oval (PW/PL = 1.38, n = 20), strongly narrowing anterad, moderately longer than sutural length of elytra, widest basad, basal margin weakly rounded; pubescence dense, directed laterally and posterolaterally; punctation small and shallow but covered with densely and uniformly.

Mesoventrite (Fig. 34): inter coxal process rather narrowly elongate, with rounded apex, completely reaching to inter coxal process of metaventrite.

Elytra (Fig. 7): together, transverse (EW/EL = 2.07, n = 20), rather small, slightly smaller than pronotum, widest at middle; fine pubescence scattered densely, diverging posteriorly in each elytron; dorsal surface rough and impressed finely and shallowly; posterolateral corners of each elytron not sinuate.

Legs (Fig. 7): simple, short, moderately slender; fore and midtibia, densely covered with undeveloped spines, respectively.

Abdomen (Fig. 7): first three visible tergites deeply impressed transversely at base; dorsal and ventral surface moderately covered with long thin setae.

Male: tergite VIII (Fig. 86): posterior margin smooth, not serrate at all, weakly but clearly emarginate broadly and medially; dorsal surface covered with setae rather densely, with approximately 10 macrosetae. Sternite VIII (Fig. 88): posterior margin broadly rounded, with a row of minute sensory setae sparsely (see Yamamoto & Maruyama, 2012: 10), and with a complex-cluster of very minute setae just behind the row of minute setae; ventral surface covered with setae densely, with approximately 13 macrosetae. Median lobe of aedeagus (Figs 90–91): [lateral view (Fig. 90)]: robust, gradually narrowing apically; apical lobe sharply pointed, moderately hook-shaped at apex; [parameral view (Fig. 91)]: bulbous, with basal part widely rounded; apical lobe abruptly narrowing strongly near apex, with narrowly and sharply pointed apex; a series of complex sclerites, not reaching to basal 1/3 of median lobe.

Female: tergite VIII (Fig. 87): posterior margin as in male; dorsal surface covered with setae densely, with approximately 11 macrosetae. Sternite VIII (Fig. 89): posterior margin very weakly rounded broadly or almost truncate; ventral surface covered with setae densely, with approximately 13 macrosetae; no complex-cluster of minute setae situated near posterior margin. Spermatheca (Fig. 92): C-shaped; apical invagination of spermatheca deep and conical in shape; spermathecal head and neck forming elliptical shape together, but with truncate apex; attachment of spermathecal duct relatively conspicuous; basal part of spermathecal stem bent weakly at middle, as long as or slightly longer than spermathecal head and neck combined; chitinized portion of spermathecal stem long, almost 1.5 times as long as spermathecal head and neck combined; each part of spermatheca uniformly and weakly sclerotized; inner wall of spermathecal head and neck rather densely striate, that of basal part not reticulate at all.

Distribution. Japan (Ishigaki-jima Is., Iriomote-jima Is.: Yaeyama Islands, the Ryûkyûs).

Etymology. Named after the type locality, Yaeyama Islands.

Bionomics. SY collected A. yaeyamensis n. sp. from chicken-baited carrion traps set in evergreen broadleaved forests on subtropical Ishigaki Island and adjacent Iriomote Island, Yaeyama Islands, the Ryûkyûs. The habitat of the holotype is shown here (Fig. 120). The detailed lifestyle is still unknown at present, although the population increases from mid-spring to early summer (March to May).

Host records. No host record is available.

Comments. This new species is seemingly endemic to Ishigaki Island and Iriomote Island (Fig. 126: arrow). Aleochara yaeyamensis n. sp. is abundant in forest environments on both islands, despite the limited species distribution. Further faunistic surveys of adjacent islands are needed to confirm its distribution range.