Synapsis puluongensis, Bui & Bonkowski, 2018

Bui, Van Bac & Bonkowski, Michael, 2018, Synapsis puluongensis sp. nov. and redescription of S. horaki (Coleoptera: Scarabaeidae), with a key to Vietnamese species, Acta Entomologica Musei Nationalis Pragae (Acta. Ent. Mus. Natl. Pragae) 58 (2), pp. 407-418 : 408-413

Synapsis puluongensis sp. nov.

( Figs 1 A–F, 2A,C,E)

Type locality. Vietnam, Thanh Hoa Province, Puluong Nature Reserve, 20º28′54″N 105º14′31″E, 950 m a.s.l.

Type material. HOLOTYPE: ♁ ‘ VIETNAM | THANH HOA Prov. | Pu Luong Nat. Reserve, near Ban Ba vill. | 20º28’54’’N 105º14’31’’E, 950 m | primary forest | 10.–25.iv.2016 | Van Bac Bui leg.’ ( VNUF) . PARATYPES (five specimens): ♁, ‘ VIETNAM | THANH HOA Prov. | Pu Luong Nat. Reserve, near Ban Ba vill. | 20º28’55’’N 105º14’29’’E, 958 m | primary forest | 10.–25.iv. 2016 | Van Bac Bui leg.’ ( VNUF); ♀, ‘VIETNNAM | THANH HOA Prov. | Pu Luong Nat. Reserve, near Ban Ba vill. | 20º28’54’’N 105º14’29’’E, 954 m | primary forest | 10.–25.iv.2016 | Van Bien Nguyen leg.’ ( VNUF); 3♀♀, ‘ VIETNAM | THANH HOA Prov. | Pu Luong Nat.Reserve, near Ban Ba vill. | 20º28’56’’N 105º14’28’’E, 956 m | primary forest | 10.–25.iv.2016 | Van Bac Bui leg.’ (2 PLNR, 1 NMPC).

Diagnosis. Body length 17.2–18.5 mm, body width 10.4– 11.5 mm; hypomeral cavities not covered by macrosetae; mesepisternal cavities absent; genae unexpanded; frons unarmed; anterolateral angles of pronotum not protruding; elytral striae strongly punctate; elytral intervals impunctate, convex and glossy, interval 2 near base not swollen; ventral sides of metafemora densely punctate.

Description of holotype (male). Body length 18.38 mm, body width 11.32 mm. Whole surface black, very shiny and glabrous. Margins of legs and pronotum with reddish- brown macrosetae.

Head broad (HeadL 3.67 mm, HeadW 7.44 mm), extremely rugose anteriorly; posterior part sparsely punctate; fine punctures surrounding eyes. Anterior margin of clypeus bidentate, V-shaped, flexed upwards, with few reddish setae. Distance between apices of clypeal denticles (DDC) 1.43 mm. Genae rectangular, quite distinctly separated from clypeus and frons by well-defined suture with sculptural punctures. Genae closely and evenly punctate, with scanty reddish macrosetae. Frons glabrous and very unevenly punctate. Area surrounding eyes bearing more closely spaced and coarser punctures than base. Frons unarmed, only slightly swollen. Antennae composed of 9 antennomeres. Antennomere I 1.34 mm in length, longer than antennomeres II–IV combined (1.25 mm in length). Antennomeres I and II darker, bearing more yellow macrosetae than remaining antennomeres.

Prothorax. Pronotum transverse (PronL 4.9 mm, PronW 10.08 mm), widest at anterior quarter, with two distinct lateral carinae at each side. Area between carinae black, matte, glabrous and not punctate. Outer margin of outer carina with dense reddish-brown macrosetae. Anterolateral angles short and not protruding. Punctures not evenly distributed, denser at sides. Only small area at anterior edge of pronotal collar microrugose. Hypomeral cavities present but shallow, sparsely punctate and not covered with macrosetae. Meso-metaventrum quite smooth, with a few scattered fine punctures at its anterior end, bearing posterior median groove and deep excavation near metacoxae.

Pterothorax. Elytra (ElyL 11.4 mm, MWoI123: 2.51 mm) convex, very shiny, deeply striate; elytral striae strongly, densely punctate (DP10, 15: 1.03 mm); intervals smooth and impunctate. Interval 2 near base not swollen. Mesepimeron and metepisternum flat, granulose and without macrosetae.

Legs. Protibia (ProTiL 3.30 mm, ProTiW 2.35 mm, ProTiSL 1.21 mm) tridentate, terminal tooth as long as protibial spur and nearly as long as protibial tarsus. Mesotibia (MesoTiL 3.34 mm, MesoTiW 1.33 mm, 1 stMesoTiSL 2.09 mm, 2 ndMesoTiSL 0.9 mm) and metatibia (MetaTiL 4.95 mm, MetaTiW 1.27 mm, MetaTiSL 1.55 mm) with red scanty macrosetae and slender spurs. Metatarsomeres nearly similar in size (MetaTaL 3.72 mm, MetaTa1L 1.08 mm, MetaTa1W 0.68 mm, MetaTa5W 0.32 mm).

Abdomen and pygidium. Abdominal ventrites opaque, sparsely punctate, and narrower at midline. Pygidium (PyL 2.46 mm, PyW 4.5 mm) feebly convex, densely and transversely punctate and scabrous.

Aedeagus ( Figs 1E, F ). Phallobase length 3.57 mm in lateral view, with strong swelling in middle of basal suture. Parameres length 2.19 mm (in lateral view), triangle-shaped. Phallobase and parameres forming angle> 130º.

Sexual dimorphism. Females differ from males in their weaker elytral striae, and meso- and metatrochanters with sparser reddish-brown macrosetae (absent in some specimens). Sexes also differ in the shape and strength of the metafemoral tooth, which is stronger in males. Compound eyes black in females but reddish brown in males.

Morphometrics. See Table 1 .

Differential diagnosis. Synapsis puluongensis sp. nov. belongs to the S. birmanica group, as indicated by a combination of the following characters: hypomeral cavities present, genae unexpanded, frons unarmed, mesepisternal cavities absent, and upper longitudinal carina of male metatibia without brush of rusty setae. Species of the S. birmanica group may be clearly distinguished from those of S. ovalis , S. brahmina and S. tmolus groups by the presence of hypomeral cavities. The S. ritsemae group has expanded genae, in which it differs from the species of the S. birmanica group whose genae are unexpanded.

Synapsis puluongensis sp. nov. can be distinguished from other known species of the group by the following characters: in S. puluongensis the elytral interval 2 is not swollen near the base (swollen in S. yama from northern and central Vietnam and Laos, S. horaki from northern Vietnam, S. dickinsoni from northern Thailand: Phukieo, S. ochii from northern Thailand: Chiang Mai and in S. masumotoi from Taiwan). Characters on the metafemora and elytral striae clearly differentiate S. puluongensis sp. nov. from the other species of the S. birmanica group recorded in Vietnam: both S. puluongensis sp. nov. and S. horaki have densely punctured metafemora on the ventral side, while S. yama has no punctures on the metafemur. In addition, S. puluongensis sp. nov. has coarse and closely spaced punctures on the elytral striae, which are absent or extremely weak in S. horaki ( Figs 2 A–D).

Synapsis puluongensis sp. nov. has hypomeral cavities without macrosetae, which distinguishes it from S. birmanica (hypomeral cavities are covered by a brush of rusty macrosetae). The new species has deep striae, whereas in S. birmanica the striae are feeble ( Figs 2 E–F).

Synapsis puluongensis sp. nov. is morphologically similar to S. naxiorum in its black and shiny dorsal side. However, the new species can be distinguished from S. naxiorum in having more punctures on the ventral side of the metafemora; elytral striae more densely punctate, intervals not punctate, and hypomeral cavities devoid of rusty setae ( Figs 2A,G ).

The entire surface of S. puluongensis sp. nov. is black and shiny, in contrast to the opaque surface of S. punctata from Myanmar and S. roslihashimi from Malaysia. In addition, S. puluongensis sp. nov. has convex intervals, whereas S. roslihashimi and S. punctata have flat or only weakly convex intervals. In S. punctata and S. roslihashimi all margins of intervals are punctate, whereas they are impunctate in the new species. The new species can also be distinguished from S. punctata and S. roslihashimi by the absence of hypomeral rusty macrosetae.

Etymology. The specific epithet puluongensis refers to the name of the type locality, Nature Reserve Puluong, Thanh Hoa Province, central Vietnam; adjective.

Biology. The new species was collected in primary forests on limestone bedrock. The primary forests are characterized by a complex structure with various storeys, comprising an upper storey with emergent trees more than 35 m tall, belonging to Dipterocarpaceae and Combretaceae , a dominant lower storey (various tree species from 15 to 30 m tall), and a brush layer on the forest floor containing various herbs ( Urticaceae , Araceae , Begoniaceae ), lianas and parasitic plants ( Connaraceae , Fabaceae , Orchidaceae , Loranthaceae ).

Figures

Fig. 1. Synapsis puluongensis sp. nov. A–B – male, holotype. C–D – female, paratype. E – aedeagus, lateral view. F – aedeagus, dorsal view.

Fig. 2. Morphological details of Synapsis species.A–B – elytral surface:A – S. puluongensis sp. nov. with elytral striae strongly and densely punctate and interval 2 not swollen; B – S. horaki Zídek & Pokorný, 2010, with elytral striae impunctate and interval 2 swollen. C–D – metafemora: C – S. puluongensis sp. nov.; D – S. yama Gillet, 1911. E–F – setation of hypomeral cavities: E – S. puluongensis sp. nov.; F – S. birmanica Gillet, 1907. G – elytron of S. naxiorum Král & Rejsek, 2000 with weakly and sparsely punctate elytral striae and intervals weakly punctate. H–I – eye coloration in specimens of S. horaki Zídek & Pokorný, 2010: H – female; I – male.