Xenodacne Boyle, 1956

Skelley, Paul E., 2023, Subgenera of Dacne Latreille, 1797 (Erotylidae: Erotylinae: Dacnini) given full generic rank, Insecta Mundi 2023 (971), pp. 1-9 : 6-7

Xenodacne Boyle, 1956 , full generic status

Figures 3, 5 , 10–11

Dacne (Xenodacne) Boyle 1956: 84 . Type: Dacne picea LeConte 1875: 170 , by original designation.

Diagnosis. Some characters that help diagnose Ameridacne include: Antennal club strongly capitate to subcircular, antennomeres symmetrical. *Pronotal anterior margin straight to concave medially (not swollen covering base of head; Fig. 3 , 10–11 ). Pronotal punctures evenly distributed ( Fig. 3 ). Proventrite with lines generally short, central plate not prominent. *Lateral pronotal marginal bead thickened anteriorly ( Fig. 5 , 10–11 ). Mesocoxae broadly separated, meso-metaventrite juncture straight. Female genitalia with gonostyli absent, gonocoxite sclerotized and chisel-like. Female genitalia with segment 9 bearing rows of teeth-like lamellae.

Included species. Eight species:

Xenodacne cyclochilus ( Boyle, 1954)

Xenodacne hujiayaoi (Dai and Zhao, 2013)

Xenodacne maculata ( Chûjô, 1940)

Xenodacne picea ( LeConte, 1875)

Xenodacne pubescens ( Boyle, 1956)

Xenodacne tangliangi (Dai and Zhao, 2013)

Xenodacne zonaria zonaria ( Lewis, 1887)

Xenodacne zonaria taiwana ( Chûjô, 1976)

Distribution. Eastern Asia and western North America.

Remarks. Additional comparative diagnostics and images of Oriental species are presented in Dai and Zhao (2013a). In many ways, Xenodacne is more similar to true Dacne than other genera. The most notable differences are those stated by Boyle (1956): pronotal anterior margin not swollen and hood-like; pronotal lateral margin swollen anteriorly; and elytral punctation confused, not in distinct rows. These features could group Xenodacne with other taxa like some member of Thallis (sensu lato). Raising Xenodacne to generic level, makes Dacne more homogeneous and more clearly defined.

Figures

Figures 1–7. Pronota and antennae of Afrodacne, Dacne and Xenodacne. 1) Pronotum of Afrodacne aequinoctialis, dorsal view, basal width = 1.75 mm. 2) Pronotum of Dacne quadrimaculata, dorsal view, basal width = 1.42 mm. 3) Pronotum of Xenodacne pubescens, dorsal view, basal width = 1.06 mm. 4) Pronotum of Dacne quadrimaculata, left lateral view, margin length = 0.70 mm. 5) Pronotum of Xenodacne pubescens, left lateral view, margin length = 0.51 mm. 6) Antenna of Dacne quadrimaculata, antennomere X width = 0.24 mm. 7) Antenna of Dacne picta, antennomere X width = 0.30 mm. (Reproduced from Skelley 1997).

Figures 8–12. Dacne and Xenodacne spp. 8–11) Dorsal pronotum. 8) Dacne quadrimaculata. 9) Dacne californica. 10) Xenodacne picea. 11) Xenodacne pubescens. 12) Female genitalia Dacne quadrimaculata. (Reproduced from Boyle 1956).