Macroplea huaxiensis Lou & Liang

Lou, Qiaozhe, Yu, Peiyu & Liang, Hongbin, 2011, Two new species of Macroplea Samouelle (Coleoptera: Chrysomelidae: Donaciinae) from China, with a key to all known species, Zootaxa 3003, pp. 1-21 : 3-7

Macroplea huaxiensis Lou & Liang , sp. nov.

( Figs 1–23 , 86 , 87 )

Type locality. Huaxi District, Guizhou Province, China, 26.43578°N, 106.65092°E, 1100 m.

Types. Holotype: male, “ CHINA, Guizhou Provin., Guiyang City, Huaxi Distr. Huaxi river. 26.43578°N, 106.65092°E ”/ “ 1100 m, 2009. X.16 D. Ye Liu & Hongliang Shi coll. Institute of Zoology, Chinese Acad. Sci.”/ “ Macroplea huaxiensis NEW SPECIES, HOLOTYPE, designated by Lou and Liang, 2011” [red label]. Paratypes (total 18 specimens): 11 males and 3 females, one pair deposited in the Osaka Museum of Natural History, “ CHINA, Guizhou Provin., Guiyang City, Huaxi Distr., Huaxi river. 26.43578°N, 106.65092°E ”/ “ 1100 m, 2009. X.16 D. Larval host plants: Vallisneria natans and Ottelia acuminata . Ye Liu & Hongliang Shi coll. Institute of Zoology, Chinese Acad. Sci.”/ “ Macroplea huaxiensis NEW SPECIES, PARATYPE, designated by Lou and Liang, 2011” [yellow label]; 2 males and 2 females, “ CHINA, Guizhou Provin., Guiyang City, Huaxi Distr., Huaxi river. 26.43578°N, 106.65092°E ”/ “ 1100 m, 2008. I.06 D. Larval host plants: Vallisneria natans and Ottelia acuminata . Ye Liu coll. Institute of Zoology, Chinese Acad. Sci.”/ “ Macroplea huaxiensis NEW SPECIES, PARATYPE, designated by Lou and Liang, 2011” [yellow label].

Diagnosis. Pronotum and elytra glabrous ( Figs 5, 8 ); ventral surface covered with dense flat pubescence, mixed with sparse long individually distinguishable setae ( Figs 14, 16, 17, 19 ); antenna long, extending beyond middle of elytron ( Figs 1–4 ); fourth antennomere about 1.4 times as long as third ( Fig. 13 ); mentum with dense pubescence ( Fig. 11 ); pronotum wrinkled, with three longitudinal black stripes on disc, coarsely punctate near apical and basal margins ( Figs 5, 14 ); hypomeron with a small triangular supracoxal pubescent patch ( Fig. 14 ); elytral apex truncate, with triangular spine at outer apical angle, sutural apex angulated ( Fig. 12 ); punctures along striae arranged in paired rows ( Figs 1, 3 , 8 ); first metatarsomere longer than second ( Fig. 10 ).

Description.

Size. Male: BL = 5.1–5.4 mm, BW = 1.9–2.1 mm; female: BL = 5.4–6.4 mm, BW = 1.9–2.8 mm.

Color. Head and antenna black ( Figs 1–4 ); mouth parts brown to dark brown; pronotum yellow with three black stripes and black punctures ( Fig. 5 ); scutellum black; elytra yellow with punctures along striae black and elytral suture brown ( Figs 1, 3 ); underside black ( Figs 2, 4 ); legs yellow, apices of femora, tibiae and tarsomeres black ( Figs 1–4 ).

Head. Eyes prominent, supraocular furrow distinct ( Fig. 6 ); vertex with distinct tubercles along medial groove, with dense, flat, individually indistinguishable pubescence extending over tubercles ( Figs 6, 7 ); transverse carina behind antennal base as high as vertex, covered with long yellow setae ( Fig. 6 ); frontoclypeus with long yellowish setae ( Figs 6, 7 ); anteclypeus exposed or enclosed; labrum broad, apical margin slightly protruding, with a row of punctures at base and a few punctures at lateral sides; mentum with dense long setae, apex emarginated ( Fig. 11 ); apical labial palpomere flattened, short, broad; labial and maxillary palpi with setae restricted to mesal surface; antenna long, extending beyond middle of elytron ( Figs 1–4 ); scape (antennomere 1) with mesal surface flat, smooth, glabrous, rest of scape and antennomeres 2–11 with dense, flat pubescence, most setae individually indistinguishable ( Figs 6, 13 ); length ratio of scape and antennomeres 2–4 equals 31:16:19:26.

Thorax. Pronotum ( Figs 5, 14 ) quadrate, PL/PW = 0.99 (0.92–1.03); pronotal angles projecting, each bearing a seta (two or three setae at a single angle in a few specimens); apex slightly wider than base; apical margin convex; basal margin flat; anterolateral tubercles protruded distinctly; lateral margin gradually narrowing backwards from anterolateral tubercle; lateral margin narrowed in middle; no ridge or carina anterior to basal angle; disc slightly shiny, glabrous, with fine transverse wrinkles and fine punctures outside median groove, with scattered coarse punctures near apical and basal margins; median groove deep, wide, with fine transverse wrinkles and fine punctures at bottom; longitudinal black stripes long, exceeding anterior and posterior transverse grooves. Hypomeron ( Fig. 14 ) with wrinkles and a small triangular supracoxal pubescent patch. Prosternum ( Fig. 14 ) covered with dense flat pubescence, mixed with sparse long individually distinguishable setae, prosternum slightly convex in central area before procoxae. Scutellum ( Fig. 5 ) triangular, with sharp apex.

Elytra. EL/EW = 1.85 (1.64–1.94), widest near middle, narrowed backwards; apex truncate with triangular spine at outer angle ( Figs 1, 3 , 12 ); spine slightly longer than its width at base; punctures along striae relatively fine, arranged in paired rows; surface of intervals shiny, alternating intervals 2, 4, 6, 8 wider and convex ( Figs 1, 3 , 8 ), elytral suture convex with shallow transverse wrinkles; sutural apex with obtuse angulation ( Fig. 12 ); epipleuron as wide as outermost interval, convex, extending over spine at outer angle ( Fig. 4 ); groove at shoulder shallow, basal depression shallow, medial depression inconspicuous ( Figs 1, 3 ).

Abdomen. Sterna with dense, flat pubescence, mixed with sparse long individually distinguishable setae ( Figs 17, 19 ).

Legs. Profemur with a short linearly arranged brush of setae basally on posterior surface ( Fig. 16 ); pro- and meso-tibial spurs short, inconspicuous, metatibia slightly curved in both sex ( Figs 9, 15 ); metatarsus ( Fig. 10 ) with markedly reduced pubescence, fifth tarsomere elongate, 1.2–1.4 times as long as basal three combined, first tarsomere longer than second, second longer than third, third tarsomere cylindrical, slightly bilobed in dorsal view; tarsal claw simple, elongate, with a small tooth at base.

Male genitalia. Median lobe of aedeagus stout, slightly truncate at apex in dorsal view ( Fig. 21 ); cap of tegmen slender, more sclerotized at apical half, with several long setae at apex ( Fig. 23 ); endophallus with apex of MEG turned dorsal, two ELDs fused, enclosing MEG, PDS paired, with apex broadly expanded in dorsal view, without pELD ( Figs 21, 22 ).

Sexual dimorphism. Male generally smaller than female ( Figs 1–4 ); apical abdominal sternum with a medial depression of variable depth in male ( Fig. 17 ), such a depression is absent in female ( Fig. 19 ); hind margin of pygidium slightly rounded in male ( Fig. 18 ), truncate in female ( Fig. 20 ).

Distribution. China (Guizhou) ( Fig. 85 ).

Host plants. Vallisneria natans (Lour.) Hara and Ottelia acuminata (Gagnep.) Dandy (both Hydrocharitaceae ) are recorded as larval host plants, with the former being the major host.

Biology. The type locality of this new species is a clean river running at a moderate speed while harbouring a variety of aquatic vegetation ( Fig. 87 ). We observed larvae and cocoons (with larvae, pupae or adults inside) adhering to the roots of host plant ( Fig. 86 ). In the laboratory, adults were never observed flying, although they can walk slowly out of water for a long time (more than two hours).

Etymology. The species name huaxiensis refers to the type locality, Huaxi river.

Remarks. This new species was wrongly identified as M. japana by Zhang et al. (2010). It resembles M. japana in many characters (see the key), among which three black stripes on pronotal disc ( Figs 5 , 56 ) and a triangular supracoxal pubescent patch on hypomeron ( Figs 14 , 54 ) are shared only by these two species in Macroplea . However, M. huaxiensis can be easily separated from M. japana by the characters listed in the key. Other characters useful in separating these two species are the following: mentum is densely pubescent in M. huaxiensis ( Fig. 11 ), while the same is sparsely pubescent in M. japana ; ventral surface is mixed with sparse long individually distinguishable setae in the former ( Figs 14, 16, 17, 19 ), while such setae are absent in M. japana ; prosternum in middle part before procoxae is slightly convex in M. huaxiensis ( Fig. 14 ), however the same is distinctly convex in M. japana ( Fig. 54 ); elytral apex is truncate in M. huaxiensis ( Fig. 12 ), and the same is emarginate in M. japana ( Fig. 64 ); base of metatarsal claw with a small tooth in M. huaxiensis ( Fig. 10 ), but such a tooth is absent in M. japana ( Fig. 68 ); tip of median lobe of aedeagus is slightly truncate in M. huaxiensis ( Fig. 21 ), while the same is more acute in M. japana ( Fig. 73 ); endophallus with ELD robust and apex of PDS broadly expanded in dorsal view in the former ( Fig. 21 ), however the same are much more slender in M. japana ( Fig. 75 ).

The densely pubescent mentum ( Fig. 11 ) in M. huaxiensis is unique as the same is glabrous or sparsely pubescent in all other members of the genus. Densely pubescent mentum is a feature of Neohaemonia species distributed in the new world ( Askevold, 1988: 403).

Figures

FIGURE 85. Geographical distribution of Macroplea spp. in China.

FIGURE 86. Various stages of Macroplea huaxiensis sp. nov.

FIGURES 1 – 4. Macroplea huaxiensis sp. nov. 1. Holotype, male, dorsal view; 2. Paratype, male, ventral view; 3. Paratype, female, dorsal view; 4. Paratype, female, ventral view. Scale line = 5.0 mm.

FIGURES 5 – 20. Macroplea huaxiensis sp. nov. 5 – 13, 17, 18. Male; 14 – 16, 19, 20. Female. 5. Pronotum, dorsal view; 6. Head, dorsal view; 7. Head, lateral view; 8. Left elytron, middle part; 9. Right metatibia, lateral view; 10. Right metatarsus, lateral view; 11. Mouth parts, ventral view; 12. Apex of left elytron; 13. Antenna; 14. Pronotum, left lateral view; 15. Right metatibia, lateral view; 16. Left profemur, ventral view; 17, 19. Apical abdominal sternum; 18, 20. Pygidium. Scale lines: a = 0.5 mm. (Figs 5 – 10, 12, 14 – 20); b = 1.0 mm. (Fig. 13); c = 0.5 mm. (Fig. 11).

FIGURES 21 – 23. Macroplea huaxiensis sp. nov. Paratype. 21 – 22. Medial lobe with endophallus in it (21. Dorsal view, 22. Lateral view); 23. Tegmen, dorsal view. Scale line = 0.5 mm.

FIGURES 87 – 90. Habitat of Macroplea spp. 87. M. huaxiensis sp. nov. (Huaxi River); 88, 89. M. ranina sp. nov. (a pond at Keji Prairie). 90. M. appendiculata (upper stream of Ertix River).

FIGURES 54 – 59. Head, prothorax and pronotum of Macroplea spp. 54 – 56. M. japana from Jiangsu; 57. M. pubipennis from Ningxia; 58. M. appendiculata from Xinjiang; 59. M. mutica from Tianjin; 54. Head and prothorax, lateral view; 55. Vertex, dorsal view; 56 – 59. Pronotum, dorsal view. Scale lines = 0.5 mm.

FIGURES 60 – 67. Elytron of Macroplea spp. 60, 64. M. japana from Jiangsu; 61, 65. M. pubipennis from Ningxia; 62, 66. M. appendiculata from Xinjiang; 63, 67. M. mutica from Tianjin. 60 – 63. Left elytron, middle part; 64, 66, 67. Apex of left elytron; 65. Apexes of both elytra. Scale lines = 0.2 mm.

FIGURES 68 – 71. Tarsus of Macroplea spp. 68. M. japana from Jiangsu; 69. M. pubipennis from Ningxia; 70. M. appendiculata from Xinjiang; 71. M. mutica from Tianjin. 68, 70, 71. Right metatarsus; 69. Left protarsus. Scale lines = 0.5 mm

FIGURES 72 – 75. Macroplea japana from Jiangsu. 72. Tegmen, dorsal view of cap; 73, 74. Median lobe with endophallus in it (73. Dorsal view; 74. Lateral view); 75. Endophallus in median lobe, dorsal view. Scale line = 0.5 mm.