Skelley, Skelley, 2009

Skelley, Paul E., 2009, Pleasing fungus beetles of the West Indies (Coleoptera: Erotylidae: Erotylinae), Insecta Mundi 2009 (82), pp. 1-94 : 12-13

Subgenus AMERIDACNE Skelley , new subgenus

Type species: Dacne brodzinskyi Skelley 1997a , here designated.

Diagnosis. The primary differences that distinguish Ameridacne from other Dacnini are the shortened meso-metasternal suture and its Neotropical distribution.

Description. Length 1.8-2.2 mm; width 0.8-1.0 mm. Body elongate, subcylindrical. Head with eyes prominent; ocular striae long and distinct, attaining anterior edge of epistome; terminal maxillary and labial palpomeres acuminate; mentum broad, width = 2.0-2.5 x length, triangular. Antenna with large 3- segmented club, antennomeres IX-XI transverse.

Pronotal punctures uniform in size, evenly distributed; lateral margin thin along entire length; pronotum tumid, swollen anteriorly, projecting forward medially beyond anterior pronotal angles, anterior margin distinctly concave laterally for reception of eyes. Elytra with basal marginal bead.

Prosternum coarsely punctate, puncture size = 0.75-1.00 x ocular facet diameter. Meso-metasternal suture short, anteriorly arched ( Fig. 26-27 ); mesocoxae separated by less than their diameter. Metasternum lacking coxal lines. Abdomen with distinct coxal lines. Tarsi distinctly pentamerous.

Distribution. This subgenus is only known from the Neotropics.

Etymology. As a uniquely American group within Dacne , it is appropriate to call the subgenus “American Dacne ”, and to abbreviate and combine the roots into a single word. The gender is masculine.

Remarks. Dacne previously had three subgenera: the nominal Dacne (Holarctic distribution), Xenodacne Boyle (western US and Japan), and Afrodacne Delkeskamp (Africa) . All of these subgenera of Dacne (indeed all other Erotylinae ) possess a broad meso-metasternal suture ( Fig. 28 ) that has an internal dicondylic connection ( Leschen 2003). A shortened meso-metasternal suture with a monocondylic condition is found in other (putatively more primitive) subfamilies of Erotylidae . The scant or fossilized materials prohibit total disarticulation to determine if Ameridacne possesses the monocondylic condition. If monocondylic, then placement of Ameridacne within Erotylinae is questionable. For now, this taxon is kept within Dacnini , as a subgenus of Dacne , until further material and analyses are available.

Two species of Dacne (Dacne) are transferred to the new subgenus Ameridacne , representing new subgeneric combinations: the amber fossil D. (Ameridacne) brodzinskyi from the Dominican Republic, and the extant D. (Ameridacne) ducke from Brazil.

Figures

Figure 26-28. Dacne spp., ventral view. 26) D. brodzinskyi, amber fossil. 27) D. ducke. 28) Dacne quadripunctatus (Say).