Bolbochromus (Bolbochromus) luzonensis Li & Krikken

Li, Chun-Lin, Krikken, Jan & Wang, Chuan-Chan, 2019, Review of the genus Bolbochromus (Coleoptera, Scarabaeoidea, Geotrupidae, Bolboceratinae) in the Philippines, ZooKeys 842, pp. 135-152 : 135

Bolbochromus (Bolbochromus) luzonensis Li & Krikken sp. n. Figs 7, 8, 16, 22, 29, 30, 35, 36

Material examined.

Holotype male. The holotype is glued at a card and with the following information on the label: Philippines: Luzon, Cagayan Province, Sta. Praxedes Macatel Falls, 24-26. IV. 2012, FIT, ML Jeng, H Cahilo leg. The holotype is deposited at the National Museum of Natural Science, Taichung, Taiwan (NMNS). Paratypes: 6 males and 3 females: PHILIPPINES: Luzon, Aurora Province, stream SW of Dinadiawan, 16°02'49"N, 120°42'45"E, 180m asl, 25.V.2016, FIT, ML Jeng, TR Chen, H Cahilo (1 female at CCLI); Philippines: Luzon, Cagayan Province, Sta. Praxedes Macatel Falls, 24-26. IV. 2012, FIT, ML Jeng, H Cahilo leg. (1 male at Museum für Naturkunde der Humboldt Universität, Berlin, Germany; 1male at the Natural History Museum, London, UK; 1 male at NMNS); PHILIPPINES: Luzon, Cagayan Prov. Claveria, 3km SW of Claveria, Nr. mountain top, 80m asl, 18-27. V. 2013, 3FITs, M.-L. Jeng. (1 male at CCLI); Philippines: Luzon, Ilocos Norte Province, Adams, 7 km N of Adams, near stream, 240 m asl, 18°31'35"N, 120°54'47"E, 01-03.IV.2017, by FITs, ML Jeng, H Cahilog (1 male at CCLI); ditto, 03-06.IV.2017 (1 female at CCLI); Philippines: Luzon, Ilocos Norte Province, Adams, Sitio Malaggao, near stream, 370-400m asl, 18°27'13"N, 120°55'10"E, 31.III-02.IV.2017, by FITs, ML Jeng, H Cahilog (1 female at Naturhistorisches Museum, Wien, Austria).

Type locality.

Sta. Praxedes Macatel Falls, Cagayan Province, northern Philippines.

Description.

Males (Figs 7, 8, 16). Body length 6.3-7.2 mm; greatest width 3.4-3.9 mm. Form ovate, sides subparallel. Dorsum reddish brown to yellowish brown, shiny, with or without black markings located on head, eye canthus, base of pronotum, outer sides of elytra and scutellum, markings greatly varying in size among individuals. Antennal clubs yellowish brown. Head: Labrum with anterior margin shallowly concave centrally, sides notched, surface coarsely, transversely rugose. Labrum and mandibles visible beyond clypeus when viewed dorsally. Clypeus subtrapezoidal, anterior margin beaded with or without a small convexity at middle, protrusion at basal angle weakly developed, surface coarsely, transversely rugose. Clypeofrontal suture moderately developed. Frons with a small conical convexity at middle of base, tip rounded or weakly bilobed. Eye small, canthus wide, strongly rugose (Fig. 22). Length of antennal clubs shorter than antennal basal segments combined. Thorax: Anterior side of pronotum behind head gradually declivous, midline deeply indented on basal half along with coarse punctures. Surface of pronotum with tiny, secondary punctures sparsely but evenly distributed, large coarse punctures in fossae and both sides of pronotum, sides of basal half of midline and base of pronotum almost impunctate. Fovea vestigial. Scutellum with scattered secondary punctures, slightly longer than wide medially. Elytron: With 7 punctate striae between suture and humeral umbone, punctures coarse, stria 2 interrupted by stria 1 not reaching base, stria 5 terminated in length subequal to stria 2; intervals 1, 3 and 4 more convex and wider than others, interval 2 less convex than others. Legs: Protibia with 9 distinct teeth on outer margin, apical 2 teeth protruding, tip of apical tooth sharp and curved outwardly; metatibia with dorsal apical spur reaching to tip of metatarsomere 2. Male genitalia: Parameres half as long as basal piece, weakly sclerotized, glabrous; surface coarsely punctate (Figs 29, 30). Median lobe trilobite (Figs 35, 36), dorsal sclerite most sclerotized, lip-like in shape and strongly curved downwardly; lateral sclerites short, tightly surrounding dorsal sclerite with apex curved inwardly; supporting sclerites absent. Temones long, elongate with apical part strongly sclerotized and in shape of toothbrush-like. Basal piece with apical portion asymmetrical.

Females.

Similar to males but minor differences with protibia more robust, protibial outer teeth1 and 2 more broadened and first apical outer teeth more curved.

Diagnosis.

Bolbochromus luzonensis sp. n. is similar to B. malayensis Li & Krikken, 2013 by their smaller body size and dorsal surface markings, but it can be distinguished based on the following combination of characters: length of antennal clubs shorter than antennal basal segments combined (antennal clubs equal in length with antennal basal segments in B. malayensis ); dorsum reddish brown to yellowish brown (black in B. malayensis ); surface markings brownish yellow in B. malayensis ); clypeofrontal suture moderately developed (absent in B. malayensis ); metatibia with dorsal apical spur reaching to tip of metatarsomere 2 (reaching to tip of metatarsomere 3 in B. malayensis ).

Distribution.

Luzon main island, northern Philippines (Fig. 39).

Etymology.

The specific name refers to the geographic origin of the type series, namely Luzon island of the Philippines.

Remarks.

The distribution of Bolbochromus luzonensis sp. n. may be restricted in the main island of Luzon where the species is sympatric with Bolbochromus jengi sp. n. and has never been collected from the neighboring islands.