Calvariomorphus palauensis, 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 : 75-76

Calvariomorphus palauensis sp. nov.

( Figs 1C–D , 2A–B , 4C–D , 10 , 11 )

Type material. Holotype, male ( EUM): “ Palau \ Babeldaob Is. \ 15-18.IX.2002 \ M. Sato leg.” . Paratype, male ( EUM): “ Palau \ Babeldaob Is. \ 14-VII-2002 \ K. Takahashi ” . Paratype, female ( EUM): “ Palau \ Babeldaob Is. \ 25-VIII-2002 \ K. Takahashi ” . Paratype, female ( EUM): “ Palau \ Babeldaob Is. \ 31-VII-2002 \ K. Takahashi ” .

Diagnosis. Small species (TL ~ 1.9–2.2 mm), body widest in the middle of elytra, trigonium of penis distinctly shorter than parameroids, parameroids without denticles on outer margin, females with large oval excitator in apical region of each elytron.

Description. Body small, TL 1.9 mm, TL/EW ~ 1.6, oval, light to dark 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. 1.0 diameter.

Penis (L 0.42 mm, W 0.15 mm) elongate, symmetrical, widest at base, pala longer than parameroids, trigonium with subtriangular apex, distinctly shorter than parameroids, apices of parameroids rounded; tegmen (L 0.31 mm, W 0.20 mm) u-shaped, apices of parameres widened and armed with ca. 10 denticles; sternite IX (L 0.38 mm, W 0.24 mm) consisting of two elongate and relatively wide hemisternites, each rounded at apex, with sharp denticle; tergite VIII (L 0.50 mm, W 0.42 mm) with parameres as long as apical portion, apical margin covered with setae, apical plate with sparse microtrichia situated near apical margin; tergite IX (L 0.45 mm, W 0.52 mm) with short, apical plate, apical margin with wide u-shaped emargination, apodemes long, diverging basally, much longer than apical plate.

Female. Size similar to that in males, TL 1.90–2.20 (2.09, n = 3) mm, TL/EW ~ 1.6–1.8 (1.7). Punctation of elytra stronger, each elytron with oval excitator near apex ( Fig. 4C–D ). Excitators concave, with numerous pores and setae directed to the middle of the structures. Ovipositor long (L 1.6 mm), bursal sclerite (L 0.83 mm) elongate, wider in posterior portion, with well visible ( Fig. 11B ) helicoidal structure, anterior portion narrower, rod-like; bursella oval, with folded structure inside (spermatophore?, Fig. 11B ), accessory gland oval, narrowing posteriorly, narrower portion with circular sclerotizations ( Fig. 11C ).

Distribution. Known from the Babeldaob Is. only.

Etymology. After Republic of Palau, a country where the species was recorded.

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 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 10. Calvariomorphus palauensis sp. nov., male genitalia. A) penis, B) tegmen, C) sternite IX, D) tergite VIII, E) tergite IX. Scale bar = 0.25 mm.

FIGURE 11. Calvariomorphus palauensis sp. nov., female genitalia.A) genital tract, B) bursella and bursal sclerite, C) sclerites of accessory gland. Abbreviations: bscl—bursal sclerite, bsl—bursella, gla—accessory gland. Scale bar = 0.5 mm.