A fungus weevil, Acanthothorax, at Ikutmaju Sawmill

One adult on the ground, Tanah Merah Mangrove Coast, Merotai Besar, Tawau, 3 May 2007, 13:31

The weevil from above on graph paper: oval mottled tan-and-black body, long banded legs and long dark antennae. — 13:31:19, from above on 2 mm graph paper.

Head and pronotum from above: a broad, flattened rostrum widening to the tip, large black eyes at its base, and the antennae set at its sides. — 13:33:05, head and pronotum, close-up.

Side view: high-domed mottled elytra, broad pronotum, the flat rostrum and long antennae, legs ringed black and cream. — 13:34:21, from the side and front.

Close-up of two hind feet: cream and black rings, a broad dark lobed tarsal segment and strong curved claws. — 13:36:29, hind tarsi and claws.

Close-up of the large, finely faceted black eye at the base of the velvety, tan rostrum. — 13:38:07, eye and rostrum.

The rear of the elytra parted to show the dark, folded hind wings beneath. — 13:39:15, folded hind wings.

Reduced from the photographer's files; nothing else changed. No flash.

The record

Date	Thursday 3 May 2007
Time	13:31–13:39, early afternoon
Place	Grounds of Ikutmaju Sawmill, on the Tanah Merah Mangrove Coast, Kampung Merotai Besar, Tawau, Sabah
Habitat	Sawmill ground beside mangrove forest. The mill ran 24 hours in three shifts, and its brightly lit grounds drew insects from the mangrove at night
Substrate	On the ground; photographed on graph paper with 2 mm squares
Behaviour	Neither crawling nor flying when found; slow and clumsy
Number	One, adult
Size	About 24 mm, front of rostrum to tip of elytra, measured on the first photograph against the 2 mm grid (about 33 pixels to 1 mm); ±1 mm, as the beetle stands above the paper
Camera	Canon PowerShot A430, six frames in eight minutes, no flash
Afterwards	Returned to the grassy bush
Observer	Wong Fook Yee
iNaturalist	observation 407250352

Identification

Order Coleoptera · Superfamily Curculionoidea · Family Anthribidae (fungus weevils) · Subfamily Anthribinae · Genus Acanthothorax.
Species not determined.

Rostrum broad and flattened, widening towards the tip, with a fine line along the middle.
Antennae long, slender and dark, straight (not elbowed), set at the sides of the rostrum.
Eyes large, black, round and finely faceted, at the base of the rostrum.
Pronotum broad, with a fine ridge running across it.
Body clothed in velvety ochre-tan hairs, mottled with irregular black patches.
Legs long, ringed black and cream; a broad, dark, lobed tarsal segment and strong curved claws.
Fully developed hind wings folded under the elytra.

The broad, flat rostrum with straight antennae and the velvety mottled coat separate fungus weevils from true weevils (Curculionidae), whose antennae are elbowed. The genus Acanthothorax was given by identifiers on iNaturalist; the species was not determined.

Remarks

Fungus weevils develop in dead wood and fungus-infested timber, which a sawmill yard has in plenty. Whether this one came from the timber or flew in to the mill's lights from the mangrove was not observed.

Related: Tanah Merah Mangrove Coast: all records · Kampung Merotai Besar · Snout beetles · Beetles · Two pairs of wings
Photographs © Wong Fook Yee. Locality, date, time and behaviour are the photographer's own; genus from iNaturalist. Record page written 10 October 2026.