Megagraphydrus puzhelongi, Jia, Fenglong, 2010

Jia, Fenglong, 2010, Megagraphydrus puzhelongi, sp. n., a new water scavenger beetle from China (Coleoptera: Hydrophilidae: Hydrophilinae), Zootaxa 2498, pp. 65-68 : 65-67

Megagraphydrus puzhelongi sp. n.

( Figs. 1–7 )

Type material. Holotype: 3, CHINA: Jiangxi Province, Shangrao, Sanqingshan mount, Upper Xinjiang river, 15.xiii.2006, leg. Fenglong Jia. Paratypes (19): 4 exs., same data as holotype; 15 exs., same data as holotype but 15– 20.iv.2007. All type specimens are deposited in the collection of the Institute of Entomology, Sun Yat-sen University, Guangzhou, China.

Diagnosis. This species is easily distinguished from other members of the genus by the following combination of characters: coloration dark brown or blackish brown with elytra a little darker; preocular spots absent; maxillary palpi with apical palpomere slightly longer than penultimate one; antennae with 9 antennomeres; elytra with six irregular series of coarse punctures, inner-most series developed only, basally ground punctation extremely fine; meso- and metafemora pubescent in about basal 3/5; aedeagus with median lobe truncate apically and bilobed ventrally; parameres truncate apically ( Fig. 7 ).

Description. Form and Color. Body oblong oval, length 2.6–3.0 mm, width 1.4–1.6 mm, moderately convex in lateral view. Head dark brown, without preocular spots. Pronotum dark brown, with vaguely defined, slightly paler margins. Elytra slightly darker than pronotum, almost black, with slightly paler lateral margins. Ventral side black. Labial palpi yellow with ultimate palpomere darkened apically. Maxillary palpi and antennae reddish brown; maxillary palpomeres with dark apices, antennal club dark. Legs reddish brown, tarsi yellowish brown.

Head. Labrum with a transverse series of large punctures and fine microsculpture, lacking superficial punctation, anterior margin somewhat emarginate. Clypeus broadly emarginate anteriorly, with fine ground punctation and distinct systematic punctures, anterior and lateral marginal portions with clear microsculpture. Frontoclypeal suture distinct.

Eyes slightly protruding, not emarginate anteriorly. Frons with same ground punctation as on clypeus, systematic punctures present, clearly visible. Ultimate labial palpomere asymmetrical with straight inner face and bent outer face. Penultimate labial palpomere longer than ultimate one and slightly swollen. Maxillary palpi a little longer than width of head, with ultimate palpomere almost symmetrical, relative length of three terminal palpomeres: 2: 1.7: 2 ( Fig. 3 ). Antennae with 9 antennomeres, scape ca. as long as antennomeres 2–6 combined, antennal club compact, about as long as scape. Mentum 1.3 x as wide as long, strongly emarginate anteriorly, with strong punctures and wrinkles on lateral portion.

Thorax. Pronotum ca. 2.5 x as wide as long, rather strongly narrowed anteriorly, posterior corners broadly round ( Fig. 5 ); anterior margin smooth, with a very fine transverse groove anterolaterally, posterior margin bisinuate, without such groove; size of ground punctuation similar to that on head but sparser, lateral punctures a little finer than those on disc; surface between punctures smooth, without microsculpture; systematic punctures present and distinct. Scutellum with similar punctation as on pronotum. Elytra with ground punctation as on pronotum; bearing six series of coarse punctures (including marginal series), inner-most stria consisting of 4–8 punctures, series 3 and 5 slightly striate ( Fig. 6 ); intervals without irregular coarse punctures except occasional few punctures posteriorly near series 3 and 5. Lateral elytral margin with 1–2 minute spines at shoulders (seen from ventral side). Prosternum weakly convex, not carinate medially, with a transverse groove; anterior margin arched. Mesoventrite moderately elevate, with strongly defined median longitudinal ridge situated behind transverse ridge ( Fig. 2 ). Metaventrite with somewhat raised and convex middle portion, not projecting anteriorly between mesocoxae; whole metaventrite except for a posteromedian glabrous area on raised middle portion bearing hydrofuge pubescence. Meso- and metafemora with basal pubescence slightly extending over half the length of femora along anterior margin and three fifths along the posterior margin ( Fig. 2 ). Tibiae slender, posterior tibiae slightly longer than femora ( Fig. 4 ). Metatarsi with 5 tarsomeres, tarsomere 1 very short, tarsomere 2 as long as tarsomeres 3 and 4 combined, tarsomere 5 as long as tarsomere 2.

Abdomen. Abdomen with five exposed ventrites covered with dense uniform pubescence; first abdominal ventrite without median carina, fifth ventrite clearly emarginate apically.

Aedeagus. Aedeagus short, parameres almost as long as tegmen, with median lobe truncate and bilobed ventrally; paramere broad, excised subapically and truncate apically manubrium thin and long ( Fig. 7 ).

Etymology. Named in honor of Pu Zhelong, the founder of Hydrophilidae studies in China.

Habitat. Apparently aquatic. The type specimens were collected at the sandy edge of a large running river.

Distribution. Known only from the type locality.

Remarks. The new species has all the diagnostic features of Megagraphydrus given above. However, it is the unique among the Megagraphydrus with basal short inner-most stria on elytra, parameres widened and truncate apically, median lobe distinctly bilobed apically, and tegmen with thin and long manubrium. Such characters of the aedeagus are also shared with some species of Agraphydrus . It shows Megagryphydrus as a sister genus of Agraphydrus ( Hebauer, 2000) .

Based on elytra and aedeagus, the new species can be very easily distinguished from other known species of the genus. Among known species, this species maybe related to M. anhuianus Hebauer , another species occurring in southeastern and southern China. The furthermore characteristics can be useful to differ from the latter, e.g. by the head without preocular spots, the pronotum not widely yellowish laterally, the labrum and the anterior and lateral margins of the clypeus bearing clear microsculpture.

Besides the species described by Hansen (1999) and Hebauer (2000), this is the third species of Megagraphydrus known from Mainland China.

Figures

FIGURES 1 – 7. Megagraphydrus puzhelongi sp. n. 1) dorsal habitus; 2) ventral habitus; 3) right maxillary palpus; 4) hind leg; 5) pronotum; 6) elytra; 7) aedeagus.