Cissidium Motschulsky 1855
Creators: name: Darby, Michael
Publisher: name: Zenodo
Year: 2019
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Ptiliidae
Cissidium

description: Genus Cissidium Motschulsky, 1855
Genus of worldwide distribution particularly in the tropical regions with numerous species, many awaiting description. (Ongoing research by the author proposes to designate several subgenera.) The new species described below share the following features: body convex, pubescent, head finely margined at sides, eyes of male larger and more prominent than those of the female, antennae long, antennomere XI constricted medially producing a ‘dumbell’ or ‘hour–glass’ like figure easily mistaken for two separate antennomeres. Pronota broader than long, sides curved sometimes angulate with clearly marked raised margins, posterior margin with insinuation opposite scutellum. Elytra entire, longer than broad, generally leaving ¾ abdominal sclerites exposed. Prosternum very short anterior to procoxae which are contiguous. Mesosternum with a distinctive central keel reaching between the mesocoxae as a sharp point or wider, hind/side margin crenulate usually in posterior half, without clearly visible perforations [not withstanding that the tribe was erected to contain species with mesoventral perforations]. Metaventrum slightly longer than the mesoventrum, metacoxae separated by ± ¼ the width of the sclerite. Pygidium without teeth at apex. Dissections of the genitalia have not been attempted in some cases because external features are sufficient to determine the species and the risk of destruction to the specimens.
Key to the Sarawak species of Cissidium
1. Thorax without either foveae or distinct foveolae, mentum triangular (Figs 6F, 7B) ........................ ......................................................................................................................... C. triangulum sp. nov.
– Thorax with either foveae or distinct foveolae, mentum broadly rectangular .................................. 2
2. Thorax with a series of foveae along the posterior margin the four central ones merging to form two larger ones (Fig. 7E) ................................................................................. C. subfoveolatum sp. nov.
– Thorax foveolate but without foveae forming large depressions ..................................................... 3
3. Elytra without foveolae, larger more rounded species (Fig. 6C) ....................... C. globulum sp. nov.
– Elytra and pronotum foveolate ......................................................................................................... 4
4. More rounded species, elytral foveolation less clearly marked than pronotum ................................. ......................................................................................................................... C. marshallae sp. nov.
– Smaller, more parallel sided species ................................................................................................. 5
5. Lateral margins of mesoventrum straight forming a distinct angle with the posterior margin, mesoventral keel narrow, ± parallel sided (Fig. 8D) ............................................. C. longum sp. nov.
– Lateral margins of mesoventrum rounded, thorax densely foveolate (Fig. 8B) ................................. ........................................................................................................................... C. pauxillum sp. nov.
description: Published as part of Darby, Michael, 2019, New Ptiliidae (Coleoptera) from Sarawak in the spirit collection of the Natural History Museum, London, pp. 1-50 in European Journal of Taxonomy 512 on pages 12-13, DOI: 10.5852/ejt.2019.512, http://zenodo.org/record/2628794