Eccoptopterus formosanus Lin, Sittichaya & Smith, 2024

Sittichaya, Wisut, Lin, Ching-Shan, Smith, Sarah M., Pornsuriya, Chaninan & Cognato, Anthony I., 2024, Two new species of Eccoptopterus Motschulsky, 1863 ambrosia beetle from Taiwan and Thailand (Coleoptera, Curculionidae, Scolytinae, Xyleborini), ZooKeys 1217, pp. 247-262 : 247-262

Eccoptopterus formosanus Lin, Sittichaya & Smith sp. nov.

Fig. 2

Type material.

Holotype: • female, Taiwan, Nantou county, Ren’ai Township ; 24°0'0.3675"N, 121°0'34.4817"E; 969 m a. s. l.; a diameter 4.5 cm branch of Sapium discolor ( Euphorbiaceae ); 02. iv. 23, (C. S. Lin) ( NMNS) . Paratypes: • male, same as holotype (1, NMNS), female, (3, MSUC), 1 female, 1 male (2 NTU), 1 male, 14 females (15, CSL) • female, Nantou County ( Lugu Township ); 23°45'0.31"N, 120°48'59.99"E; 720 m a. s. l.; a diameter 5.2 cm branch of Elaeocarpus sylvestris ( Elaeocarpaceae ); 022. vi. 23, (C. S. Lin), 1 male, 4 females (5, WSTC), female (1, NMNH), (1, NHMUK) .

Diagnosis.

Female, 2.56-2.64 mm long (mean = 2.61 mm; N = 4), 2.13-2.17 × as long as wide (mean = 2.14 ×; N = 4). Medium body size, declivital armature composed of a pair of major spines on declivital summit and 2–4 minor denticles unevenly spaced on each lateral margin; protibiae slender, broadest at apical 1 / 3, outer margin armed with six or seven moderated socketed denticles; scutellum broadly linguiform; elytra tapering laterally.

Description.

Female (Fig. 2 A – E ). Black brown, procoxae light brown, profemora and mesofemora paler brown, antennae, tibiae dark brown. Head: epistoma entire, transverse, with a row of hair-like setae. Frons below upper margin of eye and above epistoma flat, flattened area broadly rounded, surface subshiny, finely reticulate, sparsely punctate, punctures bearing fine, yellowish-white, hair-like setae. Eye shallowly emarginate just above antennal insertion, upper portion slightly smaller than lower portion. Submentum triangular small, moderately impressed. Antennal scape long, normal thick, slightly longer than club (12: 10). Pedicel as broad as scape, as long as funicle. Funicle 4 - segmented, segment 1 shorter than pedicel. Club obliquely truncate, longer than wide (10: 9), type 1, segment 1 corneous, occupying basal 1 / 4, margin carinate, concave, encircling anterior face, segment 2 and 3 soft, visible on anterior face only. Pronotum: 0.97-1.00 (mean = 0.99, N = 4) × as long as wide, type 1 in dorsal view, lateral sides parallel to anterior middle, broadly rounded anteriorly; anterior margin with 4-6 serrations, median pair prominent; anterior slope strongly asperate, asperities densely spaced, rugose, lower and more transverse toward the summit; disc slightly convex, finely reticulate, dull, sparsely covered with fine punctures bearing fine short hair-like setae. Base with a tuft of short hair-like setae associated with mycangium. In lateral view short and tall, type 3, summit at middle, lateral margins obliquely costate. Elytra: 1.14-1.17 (mean = 1.16, N = 4) × as long as wide, 1.10-1.17 (mean = 1.12, N = 4) × as long as pronotum. Scutellum comparatively moderately sized, narrow, linguiform, subshiny, attached on anterior slope of elytra less visible from above. Base shallowly bisinuate, with oblique edge, humeral angles rounded, lateral side tapering from humeral angle to apex. Disc short, basal area 1 / 4 of disc slightly convex, apical 3 / 4 impressed and connecting to declivital impression; disc punctate, punctures fine confused and setose, striae and interstriae hardly marked due to irregular punctures. Declivity sulcate, with a pair of major (largest) spines on declivital summit and 2–4 much smaller denticles on declivital margin; striae and interstriae punctate, punctures small and shallow, each bearing a short, semi-recumbent seta. Legs: procoxae contiguous; prosternal coxal piece short, conical. Protibiae slender, broadest at middle; posterior face inflated, punctate, densely covered with long hair-like setae; outer margin armed with six or seven moderate socketed denticles. Meso- and metatibiae rounded, flat, mesotibiae armed with seven or eight smaller socketed denticles, metafemora and metatibiae enlarged, metatibiae without spines.

Male. (Fig. 2 F – I ). 2.18-2.30 mm (mean = 2.24 mm; N = 4) long, 1.81-2.04 (mean 1.95; N = 4) × as long as wide. Head reddish-brown, coxae light brown, femora paler brown, antennae, tibiae, pronotum and elytra dark brown in mature specimens, excepting impressed portion of pronotum is reddish-brown. Head: somewhat margined laterally and concealed under the projection of pronotum. Epistoma entire, transverse, with a row of hair-like setae. Frons below upper margin of eye and above epistoma flat, the flattened area quadrate, surface subshiny, finely reticulate, sparsely shallow punctured, each bearing a short or long hair-like seta. Eye reduced, shallowly emarginate just above antennal insertion, upper portion slightly smaller than lower portion. Submentum triangular, small, slightly impressed. Antennal scape long, normal thick, slightly longer than club. Pedicel as broad as scape, as long as funicle. Funicle 4 - segmented, segment 1 shorter than pedicel. Club obliquely truncate, longer than wide (7.5: 5.5), type 1, segment 1 corneous, occupying basal 1 / 4, margin carinate, concave, encircling anterior face, segments 2 and 3 soft, visible on anterior face only. Pronotum: 0.89-1.11 (mean = 0.99; N = 4) × as long as wide, type 1 in dorsal view, lateral sides subparallel to anterior middle, broadly rounded anteriorly; anterior margin unarmed; widely impressed on anterior slope, then gradually narrowing and slightly impressed toward disc, weakly asperate, asperities sparsely spaced, sub-rugose, becoming lower and more transverse toward the summit; slightly longitudinally impressed in middle of disc, finely reticulate, dull, sparsely covered with fine punctures bearing fine short hair-like setae. In lateral view long and tall, type 9, summit at apical 2 / 3, lateral margins obliquely costate. Elytra: 1.00-1.05 (mean = 1.04; N = 4) × as long as wide, 0.80-1.00 (mean = 0.88; N = 4) × as long as pronotum. Scutellum small, linguiform, subshiny, attachment on anterior slope of elytra less visible from above. Base procurved, with oblique edge, humeral angles rounded, subparallel-sided in basal 1 / 2, then gradually incurved to broadly rounded apex. Disc short, punctate, punctures fine confused and setose, strial setae uniseriate with long, erect hair-like setae; interstrial setae uni- or biseriate with semi-recumbent hair-like setae; basal area 1 / 4 of disc slightly convex. Declivity somewhat steeply sloping, face weakly bisulcate, declivital face much lower than declivital margin, with a pair of major spines on declivital summit and 0–2 much smaller minor tubercles on declivital margin; striae and interstriae punctate, punctures small and shallow, each bearing a short, semi-recumbent setae. Legs: procoxae narrowly separated; prosternal coxal piece short, conical. Protibiae slender, broadest at the middle; posterior face inflated, punctate, densely covered with long hair-like setae; outer margin armed with five or six moderate socketed denticles. Meso- and metatibiae rounded, flat, mesotibiae armed with six or seven smaller socketed denticles, metafemura and metatibiae enlarged, metatibiae without apical spine.

Etymology.

Formosa, the former name of Taiwan island, in reference to the collection locality of types. An adjective.

Distribution.

Taiwan (Nantou County).

Biology.

Bred from Elaeocarpus sylvestris (Lour.) Poir. ( Elaeocarpaceae ), Lithocarpus hancei (Benth.) Rehder , Quercus glauca Thunb. ex Murray ( Fagaceae ), Sapium discolor Muell. - Arg. ( Euphorbiaceae ), Trema orientale (L.) Blume ( Cannabaceae ) with a diameter of about 4.8–6.2 cm in Taiwan. The radial entrance gallery leads to several branches in various planes without enlarged brood chambers (C. S. Lin pers. obs.).

Figures

Figure 2. Eccoptopterus formosanus sp. nov. A – E holotype female A dorsal view B lateral view C frons D posterolateral view of abdomen E declivital face; F – I paratype male F dorsal view G lateral view H frons I posterolateral view of abdomen.