Exopholis philippinica Brenske 1894

Calcetas, Orlando A., Adorada, Jessamyn R. & Navasero, Mario V., 2020, Review of the genus Exopholis Motschulsky, 1859 (Coleoptera: Scarabaeidae Melolonthinae: Leucopholini) in the Philippines, Zootaxa 4859 (4), pp. 527-536 : 529-535

Exopholis philippinica Brenske 1894

( Figs. 4–13 )

Exopholis philippinica Brenske, 1894 , 38: 354-356 (original description, type locality: “ Philippinen ”); Dalla Torre, 1912: 169 (catalog); Schultze, 1916: 178 (catalog).

Lepidiota corpulenta Moser, 1910: 185 (primary description, type locality: “Mindanao, Camp Keithley, P.I.”); Dalla Torre, 1912: 170 (catalog); Schultze, 1916: 178 (catalog); new synonymy

Type material examined. Exopholis philippinica , holotype, female ( SMT): “ Philippinen ”, “ Coll. C. Felsche, Kauf 20, 1918”, “ Exopholis , philippinica, Type, ♀, Brsk ”, “ Typus, philippinica, Brenske ”, “ Unicum!”, “ Philippinen ” ( Figs. 4–6 ). Lepidiota corpulenta , syntype, female ( ZMHB): “ Philippinen, Mindanao”, “Collected by, Mrs M. Clemens ”, “Acc. No. 6883, Lot, Bu. of Sci. , P.I.” ( Figs. 7–9 ). Both specimens were only examined from photos .

Additional material examined. Philippines: LUZON: Nueva, Ecija : 1♀, San Leonardo, iii-1972, A.D. Pawar ( IRRI-AC) ; Camarines Sur: 1♀, Iriga, 02-vii-1973, Oryza sativa L., Upland, A.D. Pawar ( IRRI-AC) ; MIND- ANAO: Misamis Oriental: 6♂♂, Claveria, Kalingagan , 28-vi-1986, A. Barrion ( IRRI-AC) ; Bukidnon: 2♂♂ 1♀, Camp Maramog, 1-v-1950, P. Anonuevo ( NMM) ; 3♂♂ 1♀, Tangcolan, Bukinon, C.F. Baker ( UNSM) ; 1♂, Malay- balay, Casisang, 21-vi-1970, L.C. Raros ( UPMNH) ; 1♂ 3♀♀, 10-v-2012, M. Navasero ( UPMNH) ; Cotabato: 1♀, Banga, 24-1950, Uichanco ( UPMNH) ; Davao Del Norte: 1♂, Malamboon, Malabog, Paquibato, Mt. Makaayat ( NMM) ; Davao Del Sur: 1♂ , Davao City, Tuganay , 04-vii-1957, P.M. Narciso ( UPMNH) .

Redescription. Males: length 19.0–22.0 mm, width 10.0–12.0 mm. Body ovoid, lustrous, monochromatic to bichromatic; dark reddish brown, blackish brown to light orange; head, pronotum and scutellum usually much darker than elytra in bichromatic specimens. Dorsum covered occasionally with minute, lanceolate, yellowish-white scales; except for a row of few large, overlapping, elongate-lanceolate, parallel laterally blunt scales adjacent to fronto-lateral margin apically. Venter same dominant coloration as head and pronotum of dorsum ( Fig. 10 ).

Head. Labrum with subrugose to rugose punctures; posterior half evenly sloping downward towards posterior margin medially; each side of posterior margin with long, thick, stiff, fringed, bristle-like yellowish to orange setae; surface with few, very long yellowish to orange stiff hairs. Clypeus with medial anterior margin nearly straight to weakly convex anteriorly, without medial cleft; with round punctures of variable size near posterior margin anteriorly; longitudinally flattened laterally; margin narrowly, slightly deflexed backward laterally; surface with dense, shallow round to irregular-shaped to rugose punctures dorsally; each puncture with minute, narrow, elongate, yel- lowish white scales; not extending beyond length of puncture. Vertex with moderate to sparsely spaced, minute, round punctures; subrugose; scales distinctly larger on each side adjacent lateral margin and ocular canthus. Mentum sub-anterior margin with wide, triangulate carina; above carina with deep, rugose punctures and groove; below carina smooth, lustrous; without hairs and scales; adjacent posterior margin of mentum with few, short, fine whitish, stiff setae. Terminal maxillary palpomere cylindrical, spindle-shaped; slightly longer in males than females. Lamellae length 1.0– 1.2 mm, slightly longer than female.

Pronotum anterior margin widely concave, not carinate medially; margin slightly to strongly carinate towards anterior angle; anterior angle rectangular, rounded apically; lateral margin convex, narrow carinate; posterior angle obtuse, round apically; apical margin smooth, not carinate, concave, widely rounded medially; each side slightly sloping downward; surface with evenly spaced round to subrugose punctures; scales minute, much larger in clypeus and elytra.

Ventral surface of pronotum. Prosternum with deep mesal groove or depression; densely setose medially, sparsely setose on each side, without scales. Prosternal process triangulate, short, tapering towards anterior margin, with blunt apex, wide basally; convex laterally. Mesoventral process triangulate, rounded apically; rounded laterally; with or without acicular scales apically; surrounded with moderate-sized, stiff, yellowish-white hairs. Metaventral process length 0.7–0.9 mm (n=10), short; thickly carinate medially, narrowing towards basal margin; without hairs and scales medially. Metaventrite sparsely to evenly covered with long stiff, yellowish-white hairs except medially; lustrous medially; with or without few, dense, long lanceolate to acicular whitish to yellowish scales near posterior angle and posterior margin; mesepisternum densely covered with long, lanceolate, tapered apex scales; metepisternum and metepimera densely covered with short to moderate-sized whitish to yellowish white hairs; usually without hairs and scales medially; mesepisternum densely covered with same scales, with numerous long, stiff yellowish white hairs.

Leg. Foretibiae tridentate; apical and medial dents distinctly large; basal dent distinctly small. Longer and shorter metatibial spurs very narrow, tapered apically. Metatibiae with 17–27 spicules posteriorly.

Scutellum posterior margin sub-circular; anterior margin widely, evenly concave, smooth, rounded laterally; lateral margin minutely carinate, not carinate medially; surface with slightly larger scales than clypeus, vertex, pronotum and elytra.

Elytron anterior margin slightly sloping downward towards scutellum, smooth, not carinate; anterior angle obtuse, round apically; lateral margin evenly convex; upper lateral margin narrowly carinate and explanate; lower lateral margin thinly carinate medially, disappearing towards posterior angle; posterior angle widely rounded, smooth, not carinate; apical margin not carinate, smooth; sutural angle slightly obtuse, round apically; sutural margin with distinctly wide costa, lustrous, mostly non-scaled; with four costae; costa 1 distinct, wide, complete; costa 2 narrow, distinct, incomplete towards anterior margin, basally attached to costa 3; costa 3 faint, incomplete towards anterior margin; costa 4 indistinct, faint, incomplete towards anterior margin; apical knob of elytra without patch of scales; surface with subrugose punctures, with same scales as pronotum.

Abdomen. Adjacent to anterior margin of abdominal sternites III–VI with narrow, lustrous, non-scaled area; wider towards medially, narrower towards lateral margin; abdominal sternites with short, ovoid, lanceolate yellowish-white scales, most dense towards lateral margin; mostly with short, elongate, lanceolate scales, sparsely spaced medially.

Pygidium. Anterior margin evenly convex, thinly carinate; lateral margin thickly carinate, narrowing towards apical margin; apical margin rounded, narrowly explanate, not carinate; surface evenly covered with short lanceolate scales, tapered or round apically; with subrugose punctures.

Aedeagus. Paramere and phallobase combined length 7.4–7.7 mm. Phallobase dorsal anterior margin slightly convex mesally ( Fig. 11 ). Paramere dorsal posterior margin triangulate; with inverted lanceolate-shaped depression laterally. Apical process short, triangulate laterally; apex round; pointed at 45 ° angle; base of apical process narrow, elongate, neck-like ( Fig. 12 ).

Female. Length 19.8–26.5 mm, width 10–11 mm. Antennal club length 1–1.1 mm, slightly shorter than male. Terminal maxillary palpomere cylindrical, spindle-shaped; slightly shorter in male. Foretibiae broad. Longer and shorter metatibial spurs little wider, slightly broad or rounded apically. Metatibiae with 23–30 spicules posteriorly (n=20).

Distribution. Philippines (Luzon, Visayas, Mindanao).

Host plants. Unknown.

Remarks. The species can be distinguished from other species of Exopholis by the following combination of characters. Elytra with four distinct costae, sutural costa distinctly wide while the rest are narrow and less distinct. The pygidium has the apical margin rounded. The clypeus is distinctly upturned laterally. The apical margin of the paramere of the male genitalia is triangulate and widely rounded apically while the basal paramere is inverted, lanceolate-shaped and with a lateral depression. Exopholis philippinica can be differentiated from other species with four costae, E. hypoleuca with variable number of costae, E. borneensis with four, which are different from each other, E. lacordairei with five and E. pinguis with seven.

Sexual dimorphism is not strongly developed, the antennal club is slightly longer in males than in females. The terminal maxillary palpomere is slightly longer in males than in females. The longer and shorter metatibial spur has a tapered apex in males while it has a slightly broader apex in females. The number of posterior metatibial spicules is overlapping in range in both sexes. The species also exhibits polyphenic trait with the occurrence of variable body coloration; some specimens are reddish brown while others are blackish brown. Brenske (1894) also observed this color variability in the populations of E. hypoleuca from Borneo, Sumatra, Nias, and Ambon he found the elytra light brown to dark chestnut-brown while some individuals from Sumatra were entirely black and with brown pygidium.

Moser (1910) described L. corpulenta from three female specimens collected on Mindanao and Cebu. He described L. corpulenta using the following distinguishing characters that fit very well with the description of E. philippinica . The antennae with nine antennomeres, chestnut body color, sides of clypeus rounded, the anterior angle of the pronotum at right angle, the posterior angle of the pronotum obtuse, the scales minute and not densely punctured, the scutellum semicircular, the sides of the abdomen densely scaled and tridentate anterior tibiae.

The authors had the possibility to study only a digital photo of the syntype of L. corpulenta deposited in ZMHB ( Figs. 7–9 ). Exopholis philippinica was described according to female holotype ( Brenske, 1896). Also for this species, we studied its digital photo only ( Figs. 4–6 ). Comparison of photos of types of both species enabled us to propose following new synonymy. Examination of 23 non-type specimens of E. philippinica deposited in various Philippine institutional collections (see material examined) made us possible to clarify geographic distribution of the species in the Philippines. As well as it is known, E. philippinica is endemic to the Philippine islands ( Fig. 13 ).

Figures

FIGURE 13. Distribution of examined specimens of Exopholis philippinica Brenske, 1894 in the Philippines.

FIGURES 4–6. Exopholis philippinica Brenske, 1894, female, holotype from SMT. 4, habitus, dorsal aspect; 5, habitus, ventral aspect; 6, habitus, lateral aspect (photograph of the female type specimen from SMT, courtesy of Dr. Olaf Jaeger).

FIGURES 7–9. Lepidiota corpulenta Moser, 1910, female, syntype from ZMHB. 7, habitus, dorsal aspect; 8, habitus, ventral aspect; 9, habitus, lateral aspect (photograph of the female from ZMHB, courtesy of Dr. Johannes Frisch and Dr. Joachim Willers).

FIGURES 10–12. Exopholis philippinica Brenske, 1894, male from IRRI. 10, habitus, dorsal aspect; 11, male genitalia, dorsal aspect; 12, male genitalia, lateral aspect.