Cissidium triangulum sp. nov.

urn:lsid:zoobank.org:act: A30AC317-C75D-4534-8360-F895711D5285

Figs 6F, 7F, 8F, 9B

Diagnosis

The triangular shape of the mentum distinguishes this species from all others.

Etymology

Refers to the form of the mentum.

Type material

Holotype MALAYSIA-BORNEO • Sarawak, Mulu; Mar. 1978; N.M. Collins leg.; pitfalls in alluvial forest; BMNH.

Paratypes MALAYSIA-BORNEO • 1 spec.; same data as for holotype but 13 Mar. 1978; BMNH • 1 spec.; Sarawak, 4 th division, Gunung Mulu National Park; May–Aug. 1978; P.M. Hammond and J.E. Marshall leg., BM 1978-49; base comp litter around long house; BMNH .

Description

SIZE. Habitus (Fig. 6F), length 0.79 mm.

COLOUR. Elytra dark brown, pronotum and head yellow brown, antennae, legs, dorsal surface covered with long yellow pubescence.

HEAD. Distance across eyes 0.22 mm; antennomeres III–XI, length 0.31 mm; mentum triangular the anterior margin much longer than the basal, stipes also triangular, broadest at base (Fig. 9B).

PRONOTUM. Length 0.19 mm, width 0.28 mm, shallowly foveolate, sides straight before right angled hind angles, disc without pubescence (Fig. 7F).

ELYTRA. Length 0.41 mm, width 0.34 mm, pubescent, shallowly foveolate, sides evenly rounded, broadest before middle.

VENTRUM. Mesoventrum without pubescence, collar extending onto humeri without a terminal tooth, lateral margins almost straight before turning to meet mesocoxae, keel becoming rugose before narrowing to a point between the mesocoxae (Fig. 8F). Metaventrum with scattered pubescence throughout, posterior margin between metacoxae with two sharp points at corners, metacoxae separated by ¼ width of the sclerite.

Remarks

The form of the mentum and the mesoventral characters suggest that this species belongs either to a subgenus of Cissidium or to a separate genus.