Discoxenus kohkongensis, Kanao, Taisuke & Maruyama, Munetoshi, 2015

Kanao, Taisuke & Maruyama, Munetoshi, 2015, Eight new species, a new record, and redescription of the genus Discoxenus Wasmann, 1904: The first record of termitophilous rove beetles in Cambodia (Coleoptera: Staphylinidae: Aleocharinae), Zootaxa 4044 (2), pp. 201-223 : 211-213

Discoxenus kohkongensis n. sp.

( Figs. 7, 8 , 73–88 , 165 )

Type materials. Holotype: ♂, Koh Kong, Cambodia, 7 XII 2012, Kanao T. leg. (Colony no. KT428).

Paratypes: 2♂♂, 25♀♀, same data as holotype (1♂, completely dissected, 1♀, head and abdominal segments VIII–X dissected off).

Diagnosis. This species is distinguished from other Discoxenus species by a combination of the following four character states: macrochaetotaxy of tergites III–VIII (6, 6, 6, 6, 6, 6), sternites III–VII with macrosetae only at each posterior margin, paramere with paramerite narrow (approximately 3 times as wide as condylite) ( Fig. 87 ), and spermatheca with short basal part (approximately 1.5 times longer than apical part) ( Fig. 88 ). This species is most similar to D. minutus , but is distinguishable from it by a male aedeagal median lobe with apically and moderately pointed distal crest ( Fig. 86 ).

Description. Head ( Fig. 73 ) more than 1.3 times wider than long, with anterior margin of clypeus rounded. Antenna ( Figs. 7, 8 , 74 ) with segment I longer than other segments; segment II as long as segment IV, with 3 macrosetae; segment III trapezoidal, shorter than other segments; segment IV transverse; segment V wider than other segments; segments VI–XI successively narrowed distally; segments VI–VIII wider than long; segment IX subquadrate; segment X longer than wide; segment XI approximately 2.2 times longer than wide, narrowed apically. Labrum ( Fig. 75 , left side) with anterior margin concave; median projection of apodeme broadly rounded; 4 lateral setae present in ventral view ( Fig. 75 , right side). Mandibles ( Figs. 76, 77 ) with 2 scrobal setae, covered with approximately 30 pores. Left mandible ( Fig. 76 ) with adoral margin bisinuate. Right mandible ( Fig. 77 ) with a distinct tooth. Maxillary palpal segment III approximately 2 times longer than wide. Mentum ( Fig. 78 ) short, approximately 3.2 times wider than long, covered with around 20 pores. Labium with prementum covered with 6– 7 pores.

Pronotum ( Fig. 79 ) sparsely covered with approximately 46 macrosetae, few minute setae present around anterior margin. Elytron ( Fig. 80 ) transverse, sparsely covered with pores, several setae present at anterolateral outer corner, 12 macrosetae present on disc. Metaventrite approximately 1.5 times as long as mesoventrite.

Tergites III–IV ( Fig. 7 ) covered with few setae laterally. Tergites V–VIII with posterior half covered with several setae. Tergite VIII ( Fig. 81 ) with posterior margin pointed, 3 pairs of macrosetae present at posterior margin, 2 pairs of macrosetae present around middle. Macrochaetotaxy of abdominal tergites III–VIII = 6, 6, 6, 6, 6, 6. Sternite III ( Fig. 8 ) sparsely covered with setae. Sternites IV–VIII with a row of yellow setae at middle. Sternites III–VII with 6–10 macrosetae at posterior margin.

Male. Sternite VIII ( Fig. 82 ) with posterior half covered with few setae, 2 pairs of macrosetae present at posterior margin and middle. Median lobe of aedeagus narrowed toward apical lobe in ventral view ( Fig. 85 ); basal capsule slightly concave at middle, with distal crest moderately pointed apically in lateral view ( Fig. 86 ); apical lobe less than half as wide as basal capsule in lateral view ( Fig. 86 ). Paramere ( Fig. 87 ) with paramerite narrow, approximately 3 times as wide as condylite; velar sac sclerite with 4–5 setae; apical lobe with 2 minute setae at apex.

Female. Sternite VIII ( Fig. 83 ) with 2 pairs of macrosetae at posterior margin and middle. Spermatheca ( Fig. 88 ) with basal part approximately 1.5 times longer than apical part.

Measurement. Body length = average 1.40 mm (1.38–1.50 mm, N = 10), pronotal length = average 0.47 mm (0.41–0.51 mm, N = 10), pronotal width = average 0.70 mm (0.67–0.73 mm, N = 10), elytral length = average 0.32 mm (0.28–0.36 mm, N = 10), elytral width = average 0.36 mm (0.33–0.41 mm, N = 10).

Etymology. The specific Lathinized epithet is derived from its type locality of Koh Kong Province.

Host species. Hypotermes makhamensis Ahmad, 1965 .

Figures

FIGURES 5 – 12. Habitus. 5 – 6. Discoxenus phourini n. sp.: 5. Dorsal view, 6. Ventral view. 7 – 8. D. kohkongensis n. sp.: 7. Dorsal view, 8. Ventral view. 9 – 10. D. hirsutus n. sp.: 9. Dorsal view, 10. Ventral view. 11 – 12. D. minutus n. sp.: 11. Dorsal view, 12. Ventral view.

FIGURES 73 – 88. Discoxenus kohkongensis n. sp.: 73. Head, 74. Antenna, 75. Labrum (left side = dorsal view, right side = ventral view), 76. Mandible, left, 77. Mandible, right, 78. Mentum, 79. Pronotum, 80. Elytron, right, 81. Tergite VIII, 82. Sternite VIII, male, 83. Sternite VIII, female. 84, Tergites IX and X. 85, Median lobe of aedeagus, ventral view, 86. Median lobe of aedeagus, lateral view, 87. Paramere. 88. Spermatheca.

FIGURES 165 – 166. Habitus. 165. Discoxenus kohkongensis n. sp., 166. D. lucidus n. sp.