Oncocephala polilloana Uhmann, 1931

Calcetas, Orlando A., Staines, Charles L., Adorada, Jessamyn R., Calilung, Venus J., Caoili, Barbara L. & Jamias, Serlie B., 2021, Review of the Genus Oncocephala Agassiz, 1846 (Coleoptera: Chrysomelidae: Cassidinae: Oncocephalini) in the Philippines, The Coleopterists Bulletin 75 (2), pp. 445-458 : 455

Oncocephala polilloana Uhmann, 1931 ( Figs. 19–22 )

Oncocephala polilloana Uhmann 1931: 224 . Type locality: Philippines, Polillo ; type depository (holotype): MTD.

Redescription (n = 7). Length = 5.0– 5.9 mm (apical margin of head to apex of elytron), width = 2.5–3.0 mm (middle of elytra). Head, pronotum, elytra and legs dark brown with black tinge; antennae dark brown, only the apical antennomere paler ( Fig. 19 ). Head. Compound eyes conical dorsally; cephalic horn pear-shaped to ovoid in dorsal aspect, anterior half almost as wide as posterior half ( Fig. 20 ), boat-shaped in lateral aspect ( Fig. 21 ), each side rounded; with cephalic horn formula 6 (2-2-2). Antenna. More than 2× length of pronotum; lateral margins of antennomere 1 slightly convex; antennomere 2 almost straight; antennomere 3 distinctly longer than 4; antennomeres 3–4 broader apically; antennomeres 5–10 quadrate; antennomere 11 short, conical; antennomere 1 without striation, 2–11 with striation, 2–7 broadly striate, 8–11 finely striate. Antennal length 3.0 mm. Pronotum. Slightly wider than long; anterior margin slightly convex medially; lateral protuberance scalene, moderate, with a broad basal margin; lateral margin slightly broader towards posterior angle; anterior angle wedge-shaped, posterior angle acute; posterior margin concave laterally, convex medially; sides and medial margin broadly carinate; with 2 subapical conical tubercles; medial longitudinal cavity interrupted medially by callosity; pronotal width 1.2 mm; pronotal length 1.2 mm. Scutellar shield. Anterolateral margin wedge-shaped, posterolateral margin straight, truncate apically. Elytron. Humeral margin with 2 distinct tubercles; scutellar tubercle minute, humeral tubercle almost same height as tubercle 1 of costa II; lateral margin distinctly broader apically with pronounced medial sinuation and small, irregularly spaced teeth; exterior apical angle almost 90°, triangular, distinctly broadly elongate laterally; apical margin wedge-shaped, minutely dentate; sutural angle obtuse; with 6 distinct elytral tubercles; costa II with 2 distinct tubercles: T1 small, convex, connected to T2 basally; T2 moderate, convex, continuous longitudinally, ridge-like, with broad basal margin, coalesced, eclipsing or rendering other tubercles indistinct; T1 and T2 margins low or narrowly elevated; costa III with 1 distinct tubercle: T1 small, convex, with broad basal margin, distinctly connected by latitudinal ridge or margin to T2 of costa IV; costa IV with 2 distinct tubercles: T1 and T2 small and conical; costa V without distinct tubercle; elytral tubercle formula 6 (1-2-1-2-0); elytron width 1.3–1.5 mm; elytron length 3.5–4.0 mm. Leg. Femur slightly rugose, not tuberculate ( Figs. 19, 22 ).

Material Examined. Paratype. Philippines: LUZON: Quezon: Pollilo Is., 15-viii-1915, S. Dorlutin (4, SDEI-09779 , 09780 , 09781 , 09782 ) . Other material. Philippines: Pollilo (no other data) (1, MGFT); Pollilo Is., 15-viii-1915, S. Dorlutin (3, SDEI-09783 , 09784 , 09785 ) .

Distribution. Philippines (Luzon, Mindanao).

Host Plants. Unknown.

Remarks. This species can be distinguished from all other species of Oncocephala in this study by the humeral margin having two elytral tubercles while other species have either four or five. The tubercles are low or narrowly elevated, convex, and form a continuous longitudinal ridge which either eclipses the other tubercles, or renders the other tubercles indistinct. The anterior and posterior margins of the cephalic horn are both rounded in lateral aspect, while the anterior margin is wedge-shaped and the posterior margin rounded or boat-shaped in all the other species.

Additionally, tubercle 3 of costa II is absent in O. polilloana while it is large and distinct in all other species. Compared with O. philippinica the elytral tubercles are more pronounced.

All of the examined specimens shared similar characters: elytra with fewer and indistinct tubercles and cephalic horn distinctly ovoid in dorsal aspect.

Figures

Figs. 19–22. Oncocephala polilloana. 19) Habitus, dorsal aspect; 20) Cephalic horn, dorsal aspect; 21) Cephalic horn, lateral aspect; 22) Habitus, lateral aspect (paratype from SDEI, courtesy of K. Nadein).