Dactylosternum Wollaston, 1854

Fikáček, Martin & Gimmel, Matthew L., 2017, On the identity of Sternosternus grouvellei Guillebeau, 1894 (Coleoptera: Hydrophilidae, Phalacridae), Zootaxa 4237 (3), pp. 578-582 : 578-579

Dactylosternum Wollaston, 1854

Cercydium Klug, 1833: 160 (partim.).—Nomen nudum.

Trichopoda Brullé, 1835: 294 .—Type species: Trichopoda cassidaeformis Brullé, 1835 (by monotypy). Secondary homonym of Trichopoda Latreille, 1825 ( Diptera : Tachinidae ).

Dactylosternum Wollaston, 1854: 99 .—Type species: Dactylosternum roussetii Wollaston, 1854 (by monotypy).

Sternosternus Guillebeau, 1894 : ccvii. (Syn. nov.)—Type species: Sternosternus grouvellei Guillebeau, 1894 (by monotypy).

Macrocercyon Alluaud, 1899 .—Type species: Trichopoda cassidaeformis Brullé, 1835 (replacement name for Trichopoda Brullé, 1835 ).

Comments on spelling. The genus name is written as “ Stenosternus ” on the labels attached to the type specimen listed below ( Fig. 1F ); this name means “narrow sternum” and corresponds to the characteristics of the genus provided by Guillebeau (1894) in the original description. The spelling “ Sternosternus ” used in the original description is probably a typographic error introduced by the typesetter. However, Sternosternus does not fulfill the requirements of Article 32.5 of the Code ( ICZN 1999), since there is not clear evidence in the original publication or subsequent publication of the author about the intention to name the genus according to its ventral morphology, and hence the name cannot be considered an incorrect original spelling. For that reason, Sternosternus is deemed the correct spelling of the name, according to the original description.

Comments on synonymy. Based on the combination of meso- and metaventrite forming a median sternal keel, mesoventrite fused with mesanepisterna, clypeus not excised anterior of eyes, labrum concealed under clypeus, and epipleuron wide throughout elytral length, Sternosternus belongs to the tribe Coelostomatini of the hydrophilid subfamily Sphaeridiinae . Within the Coelostomatini , Sternosternus corresponds to the genus Dactylosternum by the following characters (following Hansen 1991): antenna with 9 antennomeres, antennal club compact, elytron with 10 longitudinal series of punctures, lateral margin of elytra explanate posteriorly, first abdominal ventrite with median carina. Hence, we consider Sternosternus as a junior subjective synonym of Dactylosternum .

Figures

FIGURE 1. A – F, holotype of Sternosternus grouvellei Guillebeau, 1894 (A, lateral view; B, dorsal view; C, ventral view; D, head in dorsal view; E, abdomen; F, labels). G, male genitalia of a non-type specimen of D. grouvellei from Sumatra: Fort de Kock (coll. IRSNB). Scale bar of 1 mm refers to A – E only.