Crenitis (Crenitis) aduncata, Jia, Fenglong, Tang, Yudan & Minoshima, Yûsuke N., 2016

Jia, Fenglong, Tang, Yudan & Minoshima, Yûsuke N., 2016, Description of three new species of Crenitis Bedel from China, with additional faunistic records for the genus (Coleoptera: Hydrophilidae: Chaetarthriinae), Zootaxa 4208 (6), pp. 561-576 : 562-563

Crenitis (Crenitis) aduncata sp. nov.

( Figs. 1–9 , 50 , 56–59 , 73 )

Type material: Holotype: CHINA: Yunnan: male ( SYSU) , CHINA: Yunnan Prov., Baoshan City / Baihualing Jiujiezi / 25°18′N 98°47′E 2016m / 19.iv.2015, Renchao Lin & / Yudan Tang leg. [transcribed from Chinese] . Paratypes (10 specs., SUSU, KMNH, NMPC): CHINA: Yunnan: 4 specs., same data as holotype ; 6 specs., Yunnan Prov., Baoshan / City, Baihualing / 25°10′N 98°16′E 1516m / 18.iv.2015, Renchao Lin & / Yudan Tang leg. [transcribed from Chinese].

Diagnosis. Body obovate. Head and pronotum without impression and microsculpture ( Figs. 4, 5 ). Anterior margin of labrum bearing a transverse row of setae. Pronotal punctures uneven, denser laterally than mesally. Ground punctures on elytra rather fine; ten rows of large punctures present on posterior half of elytra ( Fig. 1 ). Mesoventrite flat. Meso- and metafemora pubescent on basal four-fifths ( Figs. 2, 8, 9 ). Parameres with lateral incisions subbasally and subapically, strongly widening in midlength, with distinct hook-like lateral projection at apex. Apex of median lobe situated ca. apical ninth of paramere in length ( Fig. 50 ).

This species is very similar to C. lianggeqiui and C. obovata . Ground punctures on elytra of C. aduncata are generally finer than in C. lianggeqiui (those of C. obovata are almost the same as C. aduncata ); reliable identification requires a careful examination of the male genitalia, this species can be distinguished from these species by the distinct hook-like apical projection of the paramere ( Fig. 50 ).

Description. Length 3.6–4.0 mm, width 2.3–2.4 mm. Body obovate, attenuating posteriorly, convex ( Fig. 1 ). Color. Dorsal surface black to dark reddish brown, pronotum somewhat reddish brown, lateral margins of pronotum yellowish brown ( Figs. 1, 5 ). Maxillary and labial palps and antennae uniformly yellowish brown with infuscate antennal club. Ventral surface dark reddish brown or black, legs usually yellowish brown ( Fig. 2 ).

Head. Labrum densely punctate, with broadly emarginate anterior margin; anterior margin of labrum bearing a row of setae densely distributed ( Fig. 56 ). Clypeus truncate anteriorly, with dense punctures ( Fig. 4 ) coarser than those on labrum. Frontoclypeal suture indistinct. Punctures slightly denser on frons than on clypeus. Eyes slightly protruding. Mentum ( Fig. 56 ) transverse, ca. 2 × as wide as long, with fine punctures, shagreened, without impression; anterior margin of mentum as wide as posterior margin, truncate ( Figs. 7 , 56 ). Labial palpomere 3 asymmetrical, as long as palpomere 2. Maxillary palpomere 4 asymmetrical, ca. 2 × as long as palpomere 3 ( Figs. 7 , 58 ). Antenna with nine antennomeres, club almost as long as antennomeres 2 to 6 combined. Gula narrow, subparallel ( Fig. 7 ), gular suture slightly curved medially.

Thorax. Pronotum evenly convex, without impressions and systematic punctures; ground punctures on pronotum sparser than those on frons medially, denser and coarser laterally than mesally; intervals smooth, microsculpture absent. Lateral and anterior margins of pronotum weakly beaded ( Fig. 6 ), anterior margin clearly bisinuate, posterior margin weakly bisinuate, lateral margin evenly curved. Elytra attenuating posteriorly, systematic punctures absent. Ground punctures on elytra rather fine; ten rows of large serial punctures present on posterior half ( Fig. 1 ), lateral three rows strongly impressed, lateral two rows reaching anterior quarter ( Fig. 3 ). Sutural stria almost reaching anterior quarter, deeply impressed ( Fig. 1 ). Prosternum flat ( Figs. 2, 7 ), anterior margin broadly protruding. Mesoventrite flat ( Figs. 2, 9 ). Metaventrite covered with pubescence, bulging medially, with a small glabrous area ( Figs. 9 , 57 ). Meso- and metafemoral pubescence on basal four-fifths ( Figs. 2, 8, 9 , 59 ).

Abdomen. Abdominal ventrites densely pubescent ( Figs. 2, 8 ). First ventrite not carinate; apical margin of fifth ventrite rounded ( Fig. 8 ). Aedeagus ( Fig. 50 ). Later margins of parameres with incision subbasally, then strongly inflated apical to incision; apex with distinct hook-like tooth laterally. Median lobe strongly narrowed apically; apex of median lobe situated in ca. apical ninth of parameres. Manubrium long, apex rounded. Etymology. The species name derived from Latin “aduncatus”, hook-like, referring to the shape of the parameres.

Biology. Aquatic. Collected in a small pond with abundant leaf litter ( Fig. 73 ). Distribution. China (Yunnan).

Figures

FIGURES 1 – 9. Crenitis aduncata sp. nov. 1 – 3: Habitus (1: dorsal view, 2: ventral view, 3: lateral view); 4: head, dorsal view; 5: pronotum, dorsal view; 6: pronotum, lateral view; 7: head and prosternum, ventral view; 8: abdomen, ventral view; 9: meso- and metaventrite, ventral view.

FIGURES 50 – 55. Aedeagi, dorsal view. 50: Crenitis aduncata sp. nov.; 51: C. lianggeqiui sp. nov.; 52: Crenitis sp.; 53 – 54: C. convexa Ji et Komarek (53: from Chongqing, 54: from Ningxia); 55: C. apicalis (Reitter).

FIGURES 56 – 62. SEM photographs. 56 – 59: Crenitis aduncata sp. nov., ventral view (56: labrum and mentum, 57: metaventrite, 58: maxillary palpus, 59: metafemur); 60 – 62. C. lianggeqiui sp. nov., ventral view (60: metafemur, 61: mentum, 62: antenna and maxillary palpus).

FIGURES 73 – 74. Habitat. 73: Crenitis aduncata sp. nov. (Baihualing Mount., Yunnan); 74: C. lianggeqiui sp. nov. (Ailaoshan Mount., Yunnan).