Description of Genus Sphaeroderma

Guide to Palearctic Flea Beetle Genera
(Coleoptera: Chrysomelidae: Alticinae)

Sphaeroderma Stephens

Sphaeroderma testaceum
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Sphaeroderma Stephens, 1831:328 (type species Altica testacea F., 1775, Europe, by subsequent designation of Maulik, 1926). - Westwood, 1840:42. - Heikertinger, 1924a:35. - Heikertinger & Csiki in Junk, 1940:500. - Maulik, 1926:316. - Chen, 1933:225. - Kaszab, 1962:344. - Gressitt & Kimoto, 1963:746, 822. - Kimoto, 1965:402, 441. - Shapiro, 1965:466. - Mohr, 1966:259. - Scherer, 1969:24, 203. - Medvedev, 1992:588. - Konstantinov & Vandenberg, 1996:351.

Argosomus Wollaston, 1867:152 (type species A.epilachnoides Wollaston, 1867, Cape Verde Isl., by present designation). - Scherer, 1961:274 (synonymized).

Distribution: Cosmopolitan genus with the majority of species in the Oriental region.

Statistics: About 14 species in Palearctic, more than 150 species worldwide.

Host Plants: Carduus, Cirsium, Onopordum, Centaurea, Carthamus, Panicum, Smilax, Akebia, Cynara (Gressitt & Kimoto 1963, Medvedev & Roginskaya 1988).

Comments: Westwood (1840) designated Haltica globosa as the type species of Sphaeroderma. This was completely overlooked for the nearly 150 year history of the name. Instead, the later designation of Maulik (1926)) was widely accepted. If we follow Westwood's designation, the following nomenclatoral changes will result: Apteropeda becomes a junior synomym of Sphaeroderma, and is replaced by the latter name; Argosomus becomes available for the former Sphaeroderma species. To avoid these dramatic changes to the nomenclature we are preparing an application to the International Commission on Zoological Nomenclature for preservation of the name Sphaeroderma in its current use.

Diagnosis: Body small to medium sized, broadly oval. Color orange-yellow, reddish brown, brown or black, usually without metallic lustre, with spots or stripes on elytra.
Head hypognathous, broadly oval, flat from lateral view. Frontal ridge comparatively narrow, sometimes flat, forming elevated angular T-shaped ridge with apical margin of head capsule. Antennal calli separated from each other, slightly raised and slightly separated from frontal ridge and laterally, strongly delineated from vertex by deep furrows. Eye small. Interantennal space wider than transverse diameter of antennal socket but narrower than transverse diameter of eye. Clypeus short, labrum usual. Antenna 11-segmented, filiform.
Pronotum wide, narrowly explanate laterally, without any impressions or furrows. Procoxal cavity open behind. Intercoxal prosternal process narrow, narrowly explanate posteriorly. Mesosternum broad and short.
Elytra broad, oval, irregularly punctate, humeral calli usually well developed. Epipleuron subhorizontal, almost reaching elytral apex.
Metafemur typical. All tibiae comparatively short, thickened apically. Metatibia subcylindrical, apical 1/3 flat, with irregular longitudinal ridges and long bristles along dorsolateral margin. Metatarsus inserted apically. First metatarsal segment comparatively short, shorter than following three and not longer than following two segments combined.


Generic Key	Generic Index	Morphology	Host Plants	Overview of Palearctic Fauna	Literature Cited