Calvariomorphus malayanus, Ruta & Yoshitomi, 2022

Ruta, Rafał & Yoshitomi, Hiroyuki, 2022, Calvariomorphus-a new genus of marsh beetles (Coleoptera: Scirtidae) with remarkable elytral excitators, Zootaxa 5120 (1), pp. 65-82 : 73

Calvariomorphus malayanus sp. nov.

( Figs 1A–B , 2C–E , 3 , 4 A–B , 5A–B, E , 7A , 8 , 9 )

Type material. Holotype, male ( ZMUC): “ SINGAPORE: \ Ubin Island \ 1°24’N 103°58’E \ 3-5.xi.1991. O. Martin leg. \ Zoologisk Museum, København” . Paratypes, 2 males, 1 female ( ZMUC): same data as holotype . Paratype, male ( MNHN): “COLL. Comtesse de BÉARN \ CROISIÈRE DU “NIRVANA” \ SINGAPORE \ E. CORDIER 7.IV.1908 ”; “MUSEUM PARIS \ Comtesse de BÉARN 1909”; “Dascillide”; “? Cyphon \ sp” [handwritten by Pic] . Paratype, male ( BPBM): “MALAYA: Kuala \ Lumpur, 19km S of \ Subang, 23.XII.58”; “ T. C. Maa \ Collection \ BISHOP” . Paratype, 5 males ( ZMHB): “Hist.-Coll. ( Coleoptera ) \ Nr. 49600 \ Cyphon spec. \ Bintang, Roettger \ Zool. Mus. Berlin” . Paratype, male ( MHNG): “BORNEO—Sabah \ Sepilok \ IV-V.82, M. Horak ” .

Diagnosis. Small species (TL ~ 1.6–1.9 mm), body widest in the middle of elytra, trigonium of penis slightly longer than parameroids, females with two excitators shaped as subtle depressions in apical region of each elytron.

Description. Body very small, TL 1.60–1.87 (1.73, n = 4) mm, TL/EW ~ 1.5–1.6 (1.5), oval, brown, legs and antennae paler, yellowish, covered with yellowish semierect setae. Head strongly transverse, punctation sparse, punctures separated by ca. 2 diameters. Pronotum transverse, anterolateral and posterolateral angles right angled, lateral carinae almost straight, punctation sparse, similar to that on head. Angle between pronotum and elytra not marked in dorsal view. Scutellar shield subtriangular, impunctate. Elytra elongate, punctation stronger than on pronotum, punctures separated by ca. 1.5 diameter.

Penis (L 0.35 mm, W 0.10 mm) elongate, symmetrical, pala as long as parameroids, parameroids narrowly triangular, trigonium slightly longer than parameroids, narrow; tegmen (L 0.23 mm, W 0.15 mm) u-shaped, apices of parameres pointed; sternite IX (L 0.20 mm, W 0.12 mm) u-shaped, with subtrapezoidal basal portion; tergite VIII (L 0.29 mm, W 0.25 mm) with parameres as long as apical portion, apical portion covered with microtrichia, apical margin with short setae; tergite IX (L 0.23 mm, W 0.21 mm) with lightly sclerotized, membranous apical portion, apical margin covered with indistinct setae.

Female. Size similar to that in males, TL 1.73–1.83 (1.78, n = 2) mm, TL/EW ~ 1.5. Each elytron with two subtle excitators shaped as depressions in apical portion, each depression with micropores ( Fig. 4A, B ). Ovipositor long (L 1.37 mm), bursal sclerite elongate (L 0.17 mm).

Distribution. A widely distributed species, known from the Malayan Peninsula, Singapore, Riau Archipelago and Borneo.

Etymology. After Malayan Peninsula, the area where the species occurs.

Remarks. Bintang is sometimes called Bintam or Bintan; the area in the Riau Archipelago, close to Singapore ( Kuijten 1992).

Figures

FIGURE 1. Calvariomorphus gen. nov., dorsal view (with the exception of H). A) C. malayanus sp. nov., male, B) same, fe- male, C) C. palauensis sp. nov., male, D) same, female, E) C. sakaii sp. nov., male, F) same, female, G) C. sp. (Nicobar Islands), H) same, semilateral view. Scale bars = 0.5 mm.

FIGURE 2. Calvariomorphus gen. nov., morphology of head. A) C. palauensis sp. nov., head, ventral view, B), same, close-up of mouthparts, C) C. malayanus sp. nov., mandible, D) same, maxilla, E) same, labrum.

FIGURE 3. Calvariomorphus malayanus sp. nov., hind wing.Abbreviations:AA—anterior anal vein, AP—posterior anal vein, CuA—anterior cubital vein, CuA+AA1+2—fusion of anterior cubital and anterior anal veins, MP—posterior medial vein, r3— third radial cross-vein, RA—anterior radial vein, rp-mp2—second radio-medial cross-vein, ScP—posterior subcostal vein.

FIGURE 4. Calvariomorphus gen. nov., excitators. A) C. malayanus sp. nov., apex of elytron, areas with micropores marked with arrows, B) same, close-up, C) C. palauensis sp. nov., apices of elytra, caudal view, D) same, close-up, E) C. sp. (Nicobar Islands), apices of elytra, semilateral view, F) same, caudal view, G) same, close-up.

FIGURE 5. Calvariomorphus gen. nov., dorsal (A) and ventral (B–G) view. A) C. malayanus sp. nov., dorsal view, B) same, ventral view, C) C. sakaii sp. nov., D) same, close-up of head and mesoventrite, E) C. malayanus sp. nov., close-up of mesoven- trite, F) C. palauensis sp. nov., meso- and metaventrite, G) C. sakaii sp. nov., meso- and metaventrite.

FIGURE 7. Calvariomorphus gen. nov., abdomen. A) C. malayanus sp. nov., male, B) C. sakaii sp. nov., female, C) same, close-up of ventrite 4.

FIGURE 8. Calvariomorphus malayanus sp. nov., male genitalia, specimen from Kuala Lumpur (A–D) and Singapore (E). A) penis, B) tegmen, C) tergite VIII, D) tergite IX and sternite IX, E) terminal sclerites and aedeagus. Scale bars = 0.25 mm.

FIGURE 9. Calvariomorphus malayanus sp. nov., female genitalia. A) genital tract, B) coxites, C) bursal sclerite. Scale bar (A) = 0.5 mm.