Metapocyrtus (Trachycyrtus) siargaonon Bollino & Cabras, 2023

Cabras, Analyn A., Buenavente, Perry Archival C., Medina, Milton Norman & Bollino, Maurizio, 2023, Two new species of the genus Metapocyrtus Heller 1912 subgenus Trachycyrtus Heller, 1912 (Coleoptera, Curculionidae, Entiminae, Pachyrhynchini) from the Philippines, Zootaxa 5383 (3), pp. 383-390 : 386-389

Metapocyrtus (Trachycyrtus) siargaonon Bollino & Cabras sp. nov.

( Figures 2 , 3 F–I )

Holotype ( Fig 2 ), male: Philippines-Mindanao / Brg. Cancohoy ( Del Carmen ) / (Siargao I. — Surigao del Norte) / 23–26.V.2019 / Lg. D. Mohagan —coll. Bollino // HOLOTYPE male / Metapocyrtus (Trachycyrtus) siargaonon / BOLLINO & CABRAS, 2023 (typed on red card), will be deposited in SMTD .

Paratypes (42♂♂, 25♀♀): 8♂♂ 3♀♀: Philippines-Mindanao / Brg. Tuboran ( Del Carmen ) / (Siargao I. — Surigao del Norte) / 27–28.V.2019 / Lg. D. Mohagan —coll. Bollino, all in MBLI ; 14♂♂ 6♀♀: Philippines-Mindanao / Brg. Cancohoy ( Del Carmen ) / (Siargao I. — Surigao del Norte) / 23–26.V.2019 / Lg. D. Mohagan — coll. Bollino, all in MBLI ; 4 ♂♂ 4♀♀: Philippines-Mindanao / Brg. Consuelo ( Dapa — Siargao I.) / (Surigao del Norte) / 22–24.V.2019 / Lg. D. Mohagan —coll. Bollino, all in MBLI ; 8♂♂ 10♀♀: Philippines-Mindanao / Brg. Osmeña ( Dapa — Siargao I.) / (Surigao del Norte) / 29–31.V.2019 / Lg. D. Mohagan —coll. Bollino, all in MBLI ; 1 ♂: Philippines-Mindanao / Pamosaingan—Bucas Grande Is. / (Surigao del Norte) / 6–9.VI.2019 / Lg. D. Mohagan —coll. Bollino ; 4♂♂: Philippines-Mindanao / Libjo Municipality / (Dinagat Is. Province ) / 13.V.2019 / Lg. D. Mohagan —coll. Bollino, all in MBLI ; 1♂ 1♀: Philippines-Mindanao / Brg. Tuboran ( Del Carmen ) / (Siargao I. — Surigao del Norte) / 27–28.V.2019 / Lg. D. Mohagan —coll. Bollino, will be deposited in SMTD ; 2♂♂ 1♀: Philippines-Mindanao / Brg. Cancohoy ( Del Carmen ) / (Siargao I. — Surigao del Norte) / 23–26.V.2019 / Lg. D. Mohagan —coll. Bollino, will be deposited in CMNC . All paratypes with additional red label : PARATYPE / Metapocyrtus (Trachycyrtus) siargaonon / BOLLINO & CABRAS, 2023.

Diagnosis. The only species of the subgenus Trachycyrtus present in the Great Mindanao PAIC (Pleistocene Aggregate Island Complex, including the current islands of Bohol, Samar, Leyte, Mindanao, and other nearby smaller islands) that is similar to Metapocyrtus (Trachycyrtus) siargaonon is M. (T.) microspinosus Schultze, 1925 (Type locality: Bucas Grande, Socorro). Metapocyrtus (T.) siargaonon can be distinguished from M. (T.) microspinosus by the pronotum (barrel-shaped in siargaonon , subglobular in microspinosus) and the apex of the female elytra (with a small rounded projection in siargaonon , with a short and broad but acutely pointed spine at the apex of both elytra in microspinosus).

Description. Male.

Dimensions: LB: 6.2–7.4 (HT: 6.2 mm; â: 6.7). LR: 1.0–1.4 (1.2 mm; â: 1.2). WR: 1.0–1.2 (1.0 mm; â: 1.1). LP: 1.9–2.6 (1.9 mm; â: 2.2). WP: 2.3–3.0 (2.3 mm; â: 2.6). LE: 3.9–4.9 (3.9 mm; â: 4.4). WE: 3.1–4.0 (3.1 mm; â: 3.6). N=10

Body integument black. Body surface, rostrum, head, and underside matte.

Head dorsal surface with few metallic light brown round scales interspersed with few sub-adpressed bristles; lateroventral side below the eye with metallic cerulean piliform scales; forehead between eyes weakly bulging with distinct midline groove; eyes medium-sized, feebly convex.

Rostrum smooth, glossy, with scattered dimples, slightly longer than wide (LR/WR:1.2), dorsum with few metallic light brown or green round scales, and reclined short light bristles; lateral surface with longer adpressed light bristles; transverse basal groove deep; distinct U-shaped longitudinal groove along midline reaching middle; lateral sides moderately broadened apicad. Dorsal profile convex, more pronounced in the apical third. Antennal scape shorter than funicle, reaching the hind margin of eye, sparsely covered with adpressed whitish setae, and funicle with suberect dark setae. Funicular segment I slightly shorter than II, segments III–VI as long as wide, segment VI slightly longer than III–VI; club sub-ellipsoidal.

Prothorax barrel-shaped, widest just anterior to midpoint, narrower at anterior edge than at the posterior edge, with round, opaque light hazel scales interspersed with shiny black semispherical granules, round scales slightly denser in lateral portion, while shiny granules are confined to the central part of the dorso-lateral area. Dorsal profile slightly and evenly convex.

Elytra ovate (LE/WE: 1.25), nearly as wide as and longer than prothorax (WE/WP: 1.14; LE/LP: 1.56), weakly granulate, with short sparse reclined bristles; dorsum strongly convex, dorsal contour highest roughly at middle, lateral contour evenly arcuate, apically to the middle, apex rounded, and strong apical declivity. Elytra with round, matte light brown scales interspersed with semispherical glossy black granules, similar to the pronotum.

Legs with clavate femora, covered with reclining very pale sky-blue bristles; tibiae wrinkled and covered with very pale sky-blue bristles, outer edge of mid and hind tibiae with sky-blue small round scales; inner edge weakly serrate with few protruding teeth. Fore and mid tibiae with mucro at apex. Tarsomeres pubescent. Coxae with adpressed light bristles.

Abdomen with ventrites with sparse adpressed minute light bristles.

Male genitalia as shown in Fig. 3 F–G .

Female. Dimensions: LB: 7.1–9.0 (â: 7.7). LR: 1.1–1.4 (â: 1.2). WR: 1.1–1.5 (â: 1.25). LP: 2.0–2.4 (â: 2.1). WP: 2.0–2.9 (â: 2.6). LE: 5.1–6.5 (â: 5.5). WE: 3.8–4.6 (â: 4.1). N=10.

Females, in addition to the usual secondary sexual characteristics such as shorter hind femora and convex first ventrites, differ from males in their larger average dimensions (â LB ♂ / â LB ♀: 0.87), much wider elytra compared to the pronotum (â WP/ â WE: 0.38), and the elytral apex with a small and smooth protrusion.

Etymology. The term “Siargaonon” (inhabitant of Siargao in Filipino) refers to the population of the new species found on the island of Siargao, where it appears to be more abundant and widespread than on nearby islands.

Notes on distribution. Metapocyrtus (Trachycyrtus) siargaonon is known so far from the Islands of Siargao, Bucas Grande and Dinagat, where it can be locally common.

Note on taxonomy. We tentatively place this species in the subgenus Trachycyrtus , however, the species shares characteristics with both Trachycyrtus and Sclerocyrtus . As the genus Metapocyrtus badly needs revision with many ill-defined subgenera, the subgeneric placement of this species will be re-evaluated with the upcoming revision of the genus.

Figures

FIGURE 2. Metapocyrtus (Trachycyrtus) siargaonon, holotype, male: dorsal view (A), idem, lateral view (B); female: dorsal view (C), idem, lateral view (D).

FIGURE 3. Male genitalia: Metapocyrtus (Trachycyrtus) baltazarae, (A–E), Metapocyrtus (Trachycyrtus) siargaonon, (F–I). Aedeagus, dorsal view (A, F), idem, lateral view (B, G), sternite IX, dorsal view (C, H), endophallus in lateral view (F, G, I). In Fig. 3E the profile of the left basal diverticulum has been highlighted to allow a correct view of its morphology.