Pseudobironium convexum, Lobl & Liang Tang, 2013

Löbl, Ivan & Tang, Liang, 2013, A review of the genus Pseudobironium Pic (Coleoptera: Staphylinidae: Scaphidiinae), Revue suisse de Zoologie 120 (4), pp. 665-734 : 722-725

Pseudobironium convexum sp. nov. Figs 87-89

HOLOTYPE: Ƌ, INDONESIA, Sumatra Aceh, Mt. Leuser N. P., Ketambe 800m, 28.XI.1989, leg. I. Löbl, D. Agosti, D. Burckhardt ( MHNG).

PARATYPES: INDONESIA, with the same data as the holotype, 1 Ƌ, 2 ♀ ( MHNG) . – Mentawei, Sipora, Sereinu V-VI.1894, 2 Ƌ leg. E. Modigliani ( NMPC) . – MALAYSIA, East Malaysia , Sabah, labelled "Sandakan Borneo Baker", 2 Ƌ ( NMPC) . – West Malaysia, Lankawi, Kampung Buku , 60m, 26.XI.2001, under bark on fungi, 1 Ƌ, leg. I. Löbl ( MHNG) . – Cameron Highlands , km 29 "Power station", 21.IV.1990, 1 Ƌ leg. A. Riedel ( SMNS) . – Telantan Terenngganu Sekayu , 28.II.1997, 2 Ƌ, 3 ♀ leg. I. Jeniš ( NHMW, MHNG) . – VIETNAM, S. Vietnam , 14 km SW Bao Loc 16-29.V.1994, 6 Ƌ, 9 ♀ leg. P. Pacholátko & L. Dembický ( NHMW, MHNG) .

ADDITIONAL MATERIAL: CHINA, Hainan, Ledong County, Jianfengling 1000m, 17-24.V.2011, 1 Ƌ leg. Weng-Xuan Bi ( SNUC) .

DESCRIPTION: Length 2.90-3.60 mm, width 2.10-2.65 mm. Head and body dark brown to black, abdomen, eventually also venter of body somewhat lighter than dorsal side of body. Femora and tibiae somewhat lighter than dorsal side of body, maxillary palpi, antennae and tarsi light reddish-brown to yellowish. Maxillary palpi with palpomere IV tapering posterior mid-length, almost 3 times as long as wide. Length ratio of antennomeres as II 13: III 10: IV 20: V 20: VI 17: VII 20: VIII 19: IX 20: X 18: XI 21; antennomere XI about 2.5 times as long as wide. Head with fine and dense punctation. Pronotal punctation distinctly coarser than that on head, dense, with punctures not well delimited, puncture intervals usually about as to three times as large as puncture diameters. Elytra lacking subapical hump and lateral impression. Elytral punctation near base about as fine pronotal punctation, on most surfaces distinctly coarser, punctures fairly well delimited, puncture intervals mostly about twice to three times as large as puncture diameters. Prohypomera very finely punctate, appearing smooth. Mesoventrite without median ridge, extremely finely punctate, very finely striate near margin. Metaventrite in middle almost flat, coarsely punctate except on narrow smooth mesal area, without microsculpture. Lateral parts of metaventrite very finely punctate. Submesocoxal area about as long as third of shortest interval to metacoxa. Metacoxal process impunctate, with punctulate microsculpture and distinct median tubercle, margin truncate or slightly concave. Mesotibiae and metatibiae strongly curved, mesotibial ventral spur straight. Abdominal sternite 1 very finely punctate, with large lateral impressions, strigulate microsculpture evanescent basolaterally and often appearing punctulate apicolaterally. Following sternites very finely punctate, with strigulate microsculpture, basal wrinkles present or obsolete.

Male. Protibia longer than protarsus. Protarsus not particularly elongate, tarsomeres 1 to 3 strongly widened, narrower than apex of protibia, bearing long tenent setae. Aedeagus (Figs 87-89) 1.02-1.36 mm long, strongly sclerotized. Median lobe with basal bulb large, longer than apical process, latter narrowed apically, inflexed, with ventral side convex in basal half, oblique in apical half, tip hardly bent and stout in lateral view. Apical process with lateral tubercles. Parameres wide, narrowed toward mid-length, in apical half evenly curved and wide, with upper margin almost evenly arcuate in lateral view. Internal sac with short mesal guide-sclerites, pair of conical lateral sclerites and two small invaginated rods. Membranes of internal sac with strigulate structures overlapped by scale-like structures.

DISTRIBUTION: Indonesia: Sumatra, Mentawei, Kalimantan; West Malaysia;

Vietnam; China: Hainan?

ETYMOLOGY: Latin adjective, referring to the shape of the upper margin of the parameres.

COMMENTS: This species is very similar to P. confusum , P. carinense , P. conspectum , P. grossum , and P. vitalisi in its external characters. These species share, in addition to the tuberculate lateral sides of the apical process of median lobe, a large basal bulb of the median lobe. Pseudobironium convexum may be readily distinguished by the shape of the parameres of the aedeagus as seen in lateral view. In addition, it possesses short guide-sclerites and striate membranes of the internal sac. The specimen from Hainan possesses somewhat narrower parameres and longer quidesclerites than those in other examined specimens.

Pseudobironium grossum ( Achard, 1920) Figs 90, 91 Morphoscapha grossum Achard, 1920: 132 .

HOLOTYPE: Ƌ, NMPC, labelled: Laos (Vitalis) [handwritten] / TYPE [red, printed] Morphoscapha grossum ng.nsp J. Achard det. TYPE [handwritten, by Achard, "J.Achard det." printed] / Mus. Nat. Pragae Inv. 18 716 / Pseudobironium grossum (Achard) det. Löbl 1970.

REDESCRIPTION: Length 3.85 mm, width 2.80 mm. Body black, femora, tibiae and apical abdominal segments dark brown, tarsi and antennae light brown. Maxillary palpi with palpomere IV about 4 times as long as wide, tapering. Length ratio of antennomeres as II 15: III 14: IV 26: V 26: VI 19: VII 22: VIII 22 (right antenna broken off after antennomere VII, left antenna broken off after V). Pronotal punctation dense, with punctures not well delimited, puncture intervals usually about twice to four times as large as puncture diameters. Elytra lacking subapical hump and lateral impression. Elytral punctation near base about as fine pronotal punctation, on most surfaces distinctly coarser, with well delimited punctures and puncture intervals mostly twice to four times as large as puncture diameters. Prohypomera impunctate, not microsculptured. Mesoventrite impunctate, lacking median ridge or line, finely striate near margin. Metaventrite not microsculptured, fairly flat in middle. Median part of metaventrite coarsely and densely punctate except on smooth mesal line, punctures sharply delimited, with intervals about as to twice as large as puncture diameters. Lateral parts of metaventrite very finely punctate, appearing impunctate. Submesocoxal area about as fourth of interval to metacoxa. Metacoxal process distinctly microsculptured, with basomedian tubercle, concave margin. Mesotibiae and metatibiae weakly curved, mesotibial ventral spur straight. Abdominal sternite 1 very finely, sparsely punctate, with strigulate microsculpture, smooth basolaterally, and with shallow round impression situated posterior mid-length. Following sternites lacking wrinkles, with distinct microsculpture.

Male: Protarsus shorter than protibia, protarsomeres 1 to 3 strongly widened, about as wide as apex of protibia, with long tenent setae. Aedeagus (Figs 90, 91) 1.64 mm long. Median lobe strongly sclerotized, with basal bulb large, longer than apical process. Apical process with lateral tubercles, inflexed, ventral side oblique to mid-length, rounded in apical half, apex slightly curved, fairly narrow, with blunt tip in lateral view. Parameres with weakly sclerotized inner lobes seen in dorsal or ventral views only. Parameres in lateral view narrowed from basal third toward apical third, in apical third obliqely bent and almost evenly wide. Internal sac with fairly long mesal guide-sclerites, pair of long conical lateral sclerites each with narrow invaginated rods. Membranes of internal sac scale-like, without strigulate structures.

DISTRIBUTION: Laos.

FIGS 88-91

(88-89) Pseudobironium convexum sp. nov., aedeagus (88) and internal sac (89) in dorsal view. (90, 91) Pseudobironium grossum (Achard) , aedeagus in dorsal (90) and lateral views (91), scale bars for aedeagus = 0.2 mm, for internal sac = 0.1 mm.

COMMENTS: The species may be distinguished from other members of the subgroup by the mesally lobed parameres (seen only in dorsal and ventral views), in combination with the narrow apical part of the median lobe, the internal sac lacking vesicles and striate membranose structures and possessing curved guide-sclerites, narrow pair of conical sclerites each bearing a single invaginated rod.