Phanaeus (Notiophanaeus) pyrois Bates, 1887

Solís, Ángel & Kohlmann, Bert, 2023, New synonyms and records of Costa Rican and Panamanian dung beetles (Coleoptera: Scarabaeidae: Scarabaeinae), Insecta Mundi 2023 (972), pp. 1-21 : 4-6

Phanaeus (Notiophanaeus) pyrois Bates, 1887

Phanaeus pyrois Bates 1887: 58 .

Moctezuma and Halffter (2021: 42) stated that the elytral striae of P. pyrois are not strongly impressed basally and according to their key’s couplet 10 (2021: 54), the “elytral interstriae are distinctly flattened”. We do not agree with this statement; the elytral striae are indeed strongly impressed basally and the interstriae are convex ( Fig. 2 ), and these characters easily separate this species from P. olsoufieffi ( Fig. 1 ).

Phanaeus pyrois is the most color variable taxon of the endymion species group ( Moctezuma and Halffter 2021). However, no detailed analysis of the different color morphs has heretofore been undertaken. We present a study of several color morphs in Costa Rica ( Figs. 6–10 ) and their relative frequencies ( Fig. 11 ). Our analysis of 665 P. pyrois specimens shows metallic red ( Fig. 6 ) to be the most common color morph, followed by a dark blue ( Fig. 7 ), a dark green ( Fig. 8 ), a red with green reflections ( Fig. 9 ), and finally a dark red ( Fig. 10 ). As can be seen from figures 12 and 13, these frequencies vary geographically. There is a greater percentage of red, red with green reflections, and dark red morphs in the northern part of its range, whereas there is a greater percentage of dark blue and dark green morphs in the southern portion.

Cupello et al. (2022) have undertaken an exquisitely detailed color analysis of Bolbites onitoides Harold, 1868 another Phanaeini , on the question of whether its two-color variants (blue and red) represent distinct subspecies. They concluded that B. onitoides should be treated as a single monotypic species for the following reasons:

• Two color intermediates were found living among the main color variants (red and blue);

• the distribution of the variants overlaps;

• no other characters paralleled color variation;

• the overall geographical pattern (blue western-half and a red eastern-half) can be explained by phenomena other than (incipient) speciation, such as phenotypic plasticity and distinct selective regimes; and

• color has been extensively shown not to be a reliable indicator of speciation processes among dung beetles,

especially among the Phanaeini ( Edmonds, 1994, 2000; Edmonds and Zídek, 2004, 2010, 2012; Solís and

Kohlmann 2012; Cupello and Vaz-de-Mello 2013, 2014, 2016; Cupello et al. 2022).

The same reasoning can be applied to P. pyrois , although the number of color variants and intermediaries is greater. Notably, P. pyrois represents the northernmost distribution of a taxon of this species group having a red color. The southernmost species with red color is P. funereus in Ecuador and is repeated in Colombia and Panama by P. olsoufieffi . Interestingly, to the north of P. pyrois populations in Costa Rica, only black, blue, and green species are present. Our taxonomic conclusion is that P. pyrois is a single, monotypic, polychromatic species.

Figures

Figures 1–5. Phanaeus spp. 1) Elytra of P. olsoufieffi. 2) Elytra of Phanaeus pyrois. 3) Lamella copulatrix of P. olsoufieffi from Valle de Antón, Panama. 4) Lamella copulatrix of P. olsoufieffi from Barro Colorado Island, Panama. 5) Known distribution of Phanaeus malyi, P. pyrois, and P. olsoufieffi in lower Central America. Right arrow, Barro Colorado Island; left arrow, Valle de Antón.

Figures 6–11. 6) Red morph of P. pyrois.7). Dark blue morph of P. pyrois. 8). Dark green morph of P. pyrois. 9). Red with green reflections morph of P. pyrois. 10). Dark red morph of P. pyrois. 11). Color pie-chart of the Costa Rican P. pyrois populations, n = 665.