Notionotus attenuatus Jia & Short

Jia, Fenglong & Short, Andrew Edward Z., 2011, Notionotus attenuatus sp. n. from southern China with a key to the Old World species of the genus (Coleoptera: Hydrophilidae), Zootaxa 2830, pp. 55-58 : 55-57

Notionotus attenuatus Jia & Short , sp. n.

( Figs. 1 D, 2)

Type material. Holotype (male): Dadongshan Mount, Nanling Mountain, Guangdong Province, China, 23. vi. 2009. Fenglong Jia leg. [labeled in Chinese] ( SYSU). Paratypes (12): CHINA: Guangdong Province: same data as holotype (11 exs.: SYSU, SEMC); Dadongshan Mount, Lianzhou, 24.ix.2009, Fenglong Jia leg. (1 ex.: SYSU).

Diagnosis. Size 1.5–1.6 mm. Within Old World Notionotus , this species can be distinguished by the combination of 8-segmented antennae, lack of a sutural stria, smaller body size (less than 1.8 mm), the elytra without any pale-colored discal spots and with a darkened pronotal disc ( Fig. 1 D), and the presence of fine but distinguishable subseriate ground punctures on the elytra, and the aedeagus with the parameres narrowed to a very fine point at apex, and the median lobe in which the lateral margins are sinuate, and not parallel sided.

From the two other species known to occur in China, N. attenuatus can easily be separated from N. fenestratus by the very different dorsal coloration of the head, pronotum and elytra (as mentioned above: compare Figs. 1 A and D), the lack of detectable ground punctation, and the parallel-sided median lobe of the aedeagus in N. fenestratus . From N. notaticollis , the new species is distinctly smaller, has finer elytral ground punctation, and gradually narrower tapering parameres.

Description. Color. Head with clypeus yellow to light brown on lateral thirds and with darkened central portion. Frons brown. Maxillary palps uniformly yellow. Pronotum yellow with central quarter to third darkened to brown. Elytra mostly dark brown, with lateral margins paler in color. Head. Clypeus with very fine microsculpture in the form of faint, short transverse lines. Frons with very faint ground punctation. Eyes small, separated by 5.5 × the width of one eye, only very weakly constricted anteriorly. Antennae 8-segmented, including three-segmented pubescent club. Mentum broad, 1.8× as wide as long, almost parallel-sided, anteriorly depressed and bearing strong transverse sculpture, posteriorly smooth and shiny, without microsculpture or punctures. Gula narrowed posteriorly, without pubescence. Thorax.

Pronotum broad, widest at base, without microsculpture, about 2.7 × as wide as long, appearing impunctate at 50× magnification, although some faint punctures may be detected at higher magnification. Prosternum smooth, without median carina but with slight apicomedian angulate extension. Elytra with faint but distinguishable ground punctation which is loosely subseriate. Mesoventrite slightly depressed, with a rather strong triangular process posteromedially. Hind femora sparsely pubescent except at extreme distal apex. Abdomen. Fifth ventrite broadly truncate medially ( Fig. 2 A). Aedeagus ( Fig. 2 B) with basal piece short, slightly less than 1/3 the length of the parameres; parameres with margins nearly straight, tapering to a fine, thin point. Median lobe narrow at base, about as wide as in apical quarter, and bulging in lower third, then gradually forming a bluntly pointed apex; gonopore situated just below the apex of the medium lobe.

Etymology. The species name reflects the general body outline of this species which is slightly tapering posteriad in the posterior half ( attenuatus, Lat. , ‘tapering’).

Biology. Aquatic; the type specimens were collected in a small stream with abundant mud and decaying leaves. The stream was stagnant at the time the specimens were collected.

Distribution. Known only from two localities in Guangdong Province, China.

Figures

FIGURE 1. Habitus photographs of Old World Notionotus spp. A) N. fenestratus (specimen from China; SEMC); B) N. mazzoldii (paratype from Taiwan; SEMC); C) N. siklisi (specimen from Nepal; SEMC); D) N. attenuatus (paratype; SEMC); E) N. notaticollis (paratype from Laos; SEMC). Scale bar = 0.5 mm.

FIGURE 2. Details of N. attenuatus. A) Abdominal ventrites; B) Aedeagus.