Decadiomus Chapin, 1933

Vandenberg, Natalia J. & Hanson, Paul E., 2019, Overview of the lady beetle tribe Diomini (Coleoptera: Coccinellidae) and description of a new phytophagous, silk-spinning genus from Costa Rica that induces food bodies on leaves of Piper (Pi, Zootaxa 4554 (1), pp. 255-285: 263-264

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Decadiomus Chapin, 1933


Decadiomus Chapin, 1933 

Decadiomus Chapin 1933:96  . Type species: Diomus bahamicus Casey, 1899  , by original designation.

Diagnosis. In the New World fauna, Decadiomus  species can be distinguished from most previously known Diomini  by the combination of: antenna composed of 10 antennomeres, prosternum shaped like a short stemmed Y, short anterior to coxal cavities (about ½ diameter of cavity), intercoxal process with carinae extending to anterior margin or nearly so.

Decadiomus  differs from the new genus described in the present paper (which also has only 10 antennomeres) by having free living, predatory larvae, and also by characteristics of the male genitalia: penis with apical flagellum ( Fig. 7View FIGURES 3–12), and outer arm of capsule truncated or strongly reduced and not enclosing the ejaculatory duct prior to its entry into the main penis tube ( Figs. 11–12View FIGURES 3–12).

Genital characteristics of Decadiomus  males and females are included in the generic key, below, and also discussed by Gordon (1976) (as Diomus, floridanus  group and bigemmeus  group), and by Segarra-Carmona and Otero (2014). These characteristics may serve to differentiate Decadiomus  species from the occasional occurrence of Diomini  with 10 antennomeres from areas outside of the New World (e.g. in some individuals of Diomus flavolaterus (Lea)  from Australia).

Remarks. The following species previously classified in Diomus are hereby transferred and represent new combinations within Decadiomus  : D. balteatus (LeConte, 1878)  , D. floridanus (Mulsant, 1850)  , D. amabilis (LeConte, 1852)  , D. liebecki (Horn, 1895)  , D. myrmidon (Mulsant, 1850)  , D. humilis ( Gordon, 1976)  , D. pseudotaedatus ( Gordon, 1976)  , D. taedatus (Fall, 1901)  , D. bigemmeus (Horn, 1895)  , and D. austrinus ( Gordon, 1976)  . Decadiomus seini Segarra, 2014  is placed as a junior synonym of D. austrinus  based on the original type descriptions and illustrations, and a comparison between specimens from Puerto Rico and the type material of D. austrinus  .












Decadiomus Chapin, 1933

Vandenberg, Natalia J. & Hanson, Paul E. 2019


Chapin, E. A. 1933: 96