Syncosmetus stheno Lopes-Andrade et Grebennikov

Lopes-Andrade, Cristiano & Grebennikov, Vasily V., 2015, First record and five new species of Xylographellini (Coleoptera: Ciidae) from China, with online DNA barcode library of the family, Zootaxa 4006 (3), pp. 463-480 : 473-474

Syncosmetus stheno Lopes-Andrade et Grebennikov , sp. nov.

Figs. 25–34 , 35 , 37

Diagnosis. Prothorax with sides explanate but usually narrow, visible for most of their lengths from above; edge of lateral carina coarsely crenulated. Pronotum with longitudinal midline in low relief, forming a narrow sulcus; surface between punctures in high relief, forming lines that somewhat bifurcate and coalesce around each puncture; border along the posterior edge with surface similar to that on disc. Tegmen with apex not spoon-like shaped; anterior half membranous, with a sclerotized longitudinal stripe.

Description, holotype male ( Figs. 25–27 ). GenBank accession: KC 130816 . Fully pigmented adult. Measurements in mm: TL 1.85, PL 0.73, PW 0.88, EL 1.10, EW 1.13, GD 0.90. Ratios: PL/PW 0.83, EL/EW 0.98, EL/PL 1.52, GD/EW 0.80, TL/EW 1.64. Body rounded, extremely convex, mostly dark brown; antennae, palpi and legs yellowish brown; dorsal vestiture of minute setae with a length of a puncture-width or less; ventral vestiture of decumbent slender setae, as long as or longer than a puncture-width. Head with coarse shallow punctures, with surface between them microreticulate; vertex with a short median, barely discernible knob. Antennae bearing ten antennomeres with the following lengths (in mm, left antenna measured): 0.09, 0.04, 0.04, 0.03, 0.02, 0.02, 0.02, 0.04, 0.05, 0.08 (FL 0.13 mm, CL 0.17 mm, CL/FL 1.31). Eyes coarsely facetted, bearing about 30 ommatidia; GW 0.12 mm. Pronotum with coarse punctures separated by one to two puncture-widths, the surface between them microreticulate and in high relief forming longitudinal lines that bifurcate and coalesce around each puncture; longitudinal midline in low relief, unpunctate and glabrous, forming a narrow sulcus; anterior edge broadly rounded; anterior angles slightly produced forward; sides explanate, coarsely crenulate, narrow, visible for most of their lengths from above; posterior edge broadly rounded, the border along it with surface similar to that on disc. Scutellum very small, almost indiscernible, confused with the beginning of the median elytral keel; BW 0.02 mm. Elytra tightly locked but not fused, with coarse deep punctures, separated from each other by two puncture-widths or more, the surface between them smooth; pseudoepipleura unpunctate, glabrous, microstriated; each elytron with first longitudinal keel extending to about the middle of elytral edge; first two keels diverging close to elytral base; second and third keels not united at their apices. Prosternum in front of coxae biconcave, extremely tumid at middle and bearing a longitudinal carina at midline; punctation coarse, irregular, with surface between punctures somewhat rugose to microexcavated. Hypomera with very shallow, barely discernible punctures, and microreticulate surface. Protibia not expanded, three times as long as broad; inner facet with a conspicuous tuft of long bristles at the apical half; apical angle broadly rounded, its edge bearing a row of spines; outer edge apparently devoid of spines (a few visible at high magnifications). Meso- and metatibia not expanded, five times as long as broad; outer edge apparently devoid of spines; outer apical angle rounded, not produced; apical edge with a row of spines. Metaventrite without discrimen; punctures very coarse and separated from each other by a puncture-width or less; surface in between punctures microreticulate. Abdominal ventrites with coarse punctures, concentrated at the anterior portion of each ventrite and separated by a puncture-width or more, the surface between them microreticulate; length of the ventrites (in mm, from base to apex at the longitudinal midline) as follows: 0.26, 0.06, 0.06, 0.06, 0.15; first ventrite bearing a circular, margined setose sex patch at its center, with a transverse diameter of 0.05 mm. Male abdominal terminalia in paratypes ( Figs. 28–30, 32–34 ) with sternite VIII (Figs. 28,32) with posterior edge broad, but shorter than anterior edge, slightly curved inward; posterior angles bearing a few long setae; lateral edges slightly divergent and curved outward. Tegmen (Fig. 29,33) with anterior half mostly membranous and bearing a longitudinal median sclerotized stripe; lateral margins curved inward at basal half, then converging to a narrow apex that bears a small emargination at middle. Basal piece ( Fig. 33 ) subpentagonal. Penis (Figs. 30,34) very elongate; lateral struts linked at base and visible only at basal one-fourths; lateral edges subparallel; apex membranous.

Females. Similar to males, but devoid of abdominal sex patch. Female abdominal terminalia with conspicuous gonostyli; gonocoxites transversely divided into two parts; paraprocts shorter than gonocoxites together; opening of proctiger close to basal gonocoxites.

Variation. Males, measurements in mm (n = 4, including the holotype): TL 1.68–1.85 (1.78 ± 0.08), PL 0.58– 0.73 (0.66 ± 0.07), PW 0.83–0.88 (0.85 ± 0.02), EL 1.00–1.10 (1.05 ± 0.05), EW 1.05–1.13 (1.09 ± 0.03), GD 0.88–0.90 (0.89 ± 0.01). Ratios: PL/PW 0.68–0.83 (0.78 ± 0.07), EL/EW 0.93–1.02 (0.97 ± 0.04), EL/PL 1.46– 1.87 (1.60 ± 0.18), GD/EW 0.80–0.83 (0.82 ± 0.01), TL/EW 1.56–1.74 (1.64 ± 0.08). Females, measurements in mm (n = 7): TL 1.58–1.90 (1.70 ± 0.13), PL 0.60–0.75 (0.66 ± 0.06), PW 0.75–0.88 (0.81 ± 0.05), EL 0.95–1.15 (1.01 ± 0.07), EW 1.00–1.20 (1.08 ± 0.08), GD 0.78–0.95 (0.85 ± 0.07). Ratios: PL/PW 0.77–0.86 (0.82 ± 0.04), EL/EW 0.88–1.00 (0.94 ± 0.04), EL/PL 1.39–1.70 (1.53 ± 0.12), GD/EW 0.76–0.83 (0.79 ± 0.02), TL/EW 1.50– 1.67 (1.57 ± 0.05).

Type series. Holotype: male ( IZCAS) “P.R. CHINA, Yunnan, Jizu Shan, N25º59’02” E100º20’20”, 29.vi.2011, 2689m, sift, V. Grebennikov \ CNCCOLVG00002780 \ Syncosmetus stheno Lopes-Andrade & Grebennikov HOLOTYPUS [handwritten, red paper]”. Paratypes: 1 male (dissected, LAPC) and 4 females (2 CNCI, 1 LAPC, 1 IZCAS) “P.R. CHINA, Yunnan, Jizu Shan, N25º59’02” E100º20’20”, 29.vi.2011, 2689m, sift, V. Grebennikov”, 3 of the females additionally labelled “CNCCOLVG00002781”, “CNCCOLVG00002782” and “CNCCOLVG00002783”; 1 female ( IZCAS) “P.R. CHINA, Yunnan, Jizu Shan, N25º58.367’ E100º 21.708’ 06.vi.2008 855m, sifting, V. Grebennikov”; 2 females (1 LAPC, 1 IZCAS) “P.R. CHINA, Yunnan, Jizu Shan, N25º58’12” E100º24’50”, 30.vi.2011, 2840m, sift31, V. Grebennikov”, additionally labelled “CNCCOLVG00002778” and “CNCCOLVG00002779”; 1 male (dissected, LAPC) “P.R. CHINA, Yunnan, E slope N Gaoligongshan, N27º47’22.1” E098º32’17.7”, 24.v.2010, 3027m, sifting20, V. Grebennikov \ CNCCOLVG00000912”; 1 male ( CNCI) “P.R. CHINA, Yunnan, E slope N Gaoligongshan, N27º45’27.1” E098º35’34.5”, 02.vi.2010, 2600m, sifting26, V. Grebennikov \ CNCCOLVG00000913”. All paratypes additionally labelled \ Syncosmetus stheno Lopes-Andrade & Grebennikov PARATYPUS [yellow paper]\.

Etymology. The species epithet is a Latinized Greek mythical name of the eldest of the three Gorgon sisters; noun in apposition.

Comments. The greater part of collected specimens is from Jizu Shan, which is also the type locality. Two individuals from Gaoligong Shan with explanate sides of prothorax are larger ( Fig. 31 ). One male from each locality was dissected and considered as conspecific, although aedeagus and sternite VIII of the dissected male from Gaoligong Shan are slightly smaller ( Figs. 32–34 ). In Gaoligong Shan this species is sympatric with markedly dissimilar Sync. euryale sp. nov.. Unfortunately, there is no molecular data on Sync. stheno from Gaoligong Shan.

Figures

FIGURE 35. Known distribution of Xylographellini beetles in the Palaearctic Region outside of Japan.

FIGURE 37. Lower part of the Maximum Likelihood inference phylogram, upper part of which is depicted on Fig. 36. HT: holotype.

FIGURES 25 – 34. Syncosmetus stheno sp. nov., male holotype from Jizu Shan (Figs. 25 – 27): (25) dorsal view; (26) lateral view; (27) ventral view. Pregenital segment and aedeagus of a paratype from Jizu Shan (Figs. 28 – 30): (28) sternite VIII; (29) tegmen; (30) penis. Male paratype from Gaoligong Shan (Figs. 31 – 34): (31) dorsal view; (32) sternite VIII; (33) tegmen (left) still joined with basal piece (= phallobase; right) through membranes; (34) penis. The apices of sclerites of male abdominal terminalia are oriented to the left. Scale bars: 0.5 mm (Figs. 25 – 27, 31); 0.1 mm (Figs. 28 – 30, 32 – 34).