A revision of Cissidium Motschulsky (Coleoptera: Ptiliidae) with seventy seven new species Author Darby, Michael text European Journal of Taxonomy 2020 2020-04-02 622 1 188 journal article 22458 10.5852/ejt.2020.622 9cb3ea96-0ee4-40b4-8006-19b5fed80b46 3777282 9CD3B2CD-F072-4994-8CA9-24145D343401 Key to species group 5 1. Pronotal sides rounded....................................................................................................................... 2 – Pronotal sides angulate ...................................................................................................................... 4 2. Pronotum base with a linear row of ten foveae in two pairs of five each, the medial two pairs being larger than the outer three pairs ......................................................................... C. modestum sp. nov. – Foveae along pronotal base of the same size, more randomly arranged ........................................... 3 3. Pronotum base with ± seven foveae ...................................................................... C. upiense sp. nov. – Pronotum base with ± ten foveae.................................................................... C. sakaii Sawada, 2008 4. Head without a linear depression between the eyes .......................................................................... 5 – Head with a linear depression between the eyes ............................................... C. fraternum sp. nov. 5. Sides of mid-keel straight .................................................................... C. kolombangaricum sp. nov. – Sides of mid-keel concave ................................................................................................................ 6 6. Mid-keel short, anterior angles very wide .................................................. C. brachypterum sp. nov. – Mid keel anterior angles narrower..................................................................................................... 7 7. Mid keel shorter and wider .............................................................................. C. waginicum sp. nov. – Mid keel narrower................................................................................................. C. apterum sp. nov . Cissidium apterum sp. nov. urn:lsid:zoobank.org:act: 0CF1B47A-22B0-45A8-AE70-F24D484C01C5 Figs 6J , 107 Etymology Johnson ms name, named after the apterous male. Material examined Holotype SOLOMON ISLANDS • ♂ ; Santa Ysobel, S.E., 1000 Ships Bay , opposite Lilihinia Is.; 20 Sep. 1965 ; forest litter; P.N. Lawrence leg.; BMNH . Paratypes SOLOMON ISLANDS • 1 ♀ ; Santa Ysobel , same collection data as for holotype; BMNH • 2 ♂♂ , 2 ♀♀ ; NE Tatamba, Raja; 30 Sep. 1965 ; forest litter ; P.N. Lawrence leg.; MMUE , BMNH • 1 ♂ ; E Central San Jorge Is. ; 24 Sep. 1965 ; forest litter ; J.P. and P.N. Lawrence leg.; BMNH . Description SIZE. Habitus ( Fig. 101A ), length 0.63 mm . COLOUR. Dark yellow brown, pubescence, legs and antennae dusky yellow. HEAD. Without a clearly marked linear depression behind the eyes, width across eyes 0.22 mm ; antennomeres III–XI length 0.36 mm , III–IX length 0.20 mm , X–XI length 0.16 mm . PRONOTUM. Length 0.18 mm , width 0.32 mm , pubescent, base with a series of four or five foveae on each side, these two series separated by distinct space opposite scutellum and with a few scattered, rather large, somewhat irregular foveolae in basal half; side margins sharply angled, concave before rectangular hind angles, sinuous before obtuse anterior angles, strongly bordered, border effaced laterally on posterior margin ( Fig. 107B ). ELYTRA. Length 0.47 mm , width 0.37 mm , pubescence as pronotum, basal third sparsely covered with large foveolae. MESOVENTRITE. Medial extension of collar short, pointed; anterior margin of mid-keel wider than posterior, corners of posterior margin reaching anterior margins of mesocoxal borders; keel sharply raised anteriorly then almost parallel-sided to termination between mesocoxae; mesoventral lateral margins serrate in posterior half; humeri barely toothed, sloping posteriorly ( Fig. 107C ). METAVENTRITE. Length 0.12 mm , width across spines 0.12 mm , with scattered setae, female disc simple, male disc depressed medially; posterior margins of mesocoxal cavities serrate. WINGS. Male macropterous. Female apterous. GENITALIA. Female spermatheca globular with small accessory knob. Male aedeagus with projecting hooked tip ( Fig. 6J ). Remarks Five of the ten species of Cissidium recorded from the Solomon Islands belong in this group and are difficult to separate on pronotal characters. The genitalia distinguish this species.