Polyura bicolor ( Turlin & Sato, 1995 ) Toussaint & Moriniere & Lam & Turlin & Balke, 2016

Toussaint, Emmanuel F. A., Moriniere, Jerôme, Lam, Athena, Turlin, Bernard & Balke, Michael, 2016, Bayesian Poisson tree processes and multispecies coalescent models shed new light on the diversification of Nawab butterflies in the Solomon Islands (Nymphalidae, Charaxinae, Polyura), Zoological Journal of the Linnean Society 178 (2), pp. 241-256 : 247-248

Polyura bicolor ( Turlin & Sato, 1995) stat. nov.

Polyura epigenes bicolor Turlin & Sato, 1995: 10 .

Polyura thayn (M uller € & Tennent, 1998: 591); Turlin, 2001: 245 (synonymy).

The male holotype (‘ Malaita Islands , Solomons archipelago, VIII-1990 ’) of this species is housed in the Museum of Nature and Human Activities ( MNHA), Hyogo, Japan. Twenty-three paratypes were designated (one with the label ‘ Allotype’), and are located in the MNHA, as well as in the collections of Bernard Turlin and Hidetsugu Sato, the original authors of this species ( Turlin & Sato, 1995) .

Diagnosis

Polyura bicolor males are more brownish than the darker P. epigenes ( Fig. 6 ). The apex of the forewing is more pointed in P. bicolor and the outer margin is more deeply concave than in P. epigenes . The five discal spots and the eight submarginal dots of the upperside of the forewing are larger and white in P. bicolor compared with P. epigenes , where they are smaller and ochreous in ssp. epigenes and obsolete or even absent in ssp. monochroma . The hindwing submarginal spots are blue in P. epigenes but are light violet in P. bicolor . Male genitalia differ by the sociuncus deeply indented ventrally in P. epigenes (almost not in P. bicolor ), and by the sharp projections of the valva directed anteriorly in P. epigenes (ventrally in P. bicolor ). Females of the common form of P. bicolor and of P. epigenes are pretty similar. The wide median bar is cream in P. epigenes but is white in the common form of P. bicolor . The orange form cinereus is very distinct ( Fig. 5 ), with all light areas ochreous, and the external suffusion to the median bar of the hindwing is golden brown.

With the limited taxon sampling of P. epigenes epigenes , we choose not to synonymize P. epigenes monochroma with P. epigenes epigenes . Based on the bathymetry of the archipelago, it is likely that these two populations are not genetically distinct and do constitute a unique lineage. Additional taxon sampling will be needed to assess the potential genetic differentiation of these two populations.

Figures

Figure 5. Divergence time estimates derived from the *BEAST analysis. Chronogram derived from the posterior trees of dating analysis conducted in BEAST. The 95% credibility intervals are shown at each node of the phylogeny. A map of the Solomon Islands with bathymetry is shown at the top of the figure. The island of Malaita is highlighted in violet. A picture of a female Polyura epigenes bicolor f. cinereus (orange morph) is presented. Picture taken by Bernard Turlin. T in time bar stands for Tarantian.

Figure 6. Habitus of Polyura bicolor and Polyura epigenes across the Solomon Islands. Pictures of the upperside (left half) and underside (right half) of the two sexes. All pictures taken by Bernard Turlin.