Memphis arginussa (Geyer, 1832)

Dias, Fernando M. S., Riley, Thomas J., Casagrande, Mirna M. & Mielke, Olaf H. H., 2021, An overview of “ arginussa ” species group of Memphis Hübner, [1819], with the description of a new species from Panama (Lepidoptera: Nymphalidae: Charaxinae), Zootaxa 5061 (2), pp. 249-270 : 251-252

The “ arginussa ” species group

Based on the results of the distance analyses, and phylogenetic analyses by Toussaint et al. (2019), species formerly included by Comstock’s (1961) in VIA (“ verticordia ”) and VIB (“ arginussa ”) species groups are herein included in the monophyletic “ verticordia ” species group, including M. verticordia and M. artacaena , and “ arginussa ” species group, including M. arginussa , M. eubaena stat. rest., M. onophis stat. rest., M. lemnos , M. neidhoeferi , M. perenna , M. lankesteri stat. rest., M. pithyusa ,, and M. smalli sp. nov. ( Figs 1–4 ) and M. herbacea (Figs 5–8); M. paulus is tentatively included in this group based on morphology. The relationship between species of the “ arginussa ” species group ( Fig. 9 ) is similar to the phylogeny presented by Toussaint et al. (2019), except for while here M. neidhoeferi is recovered as sister to a branch including M. arginussa , M. onophis stat. rest. and M. eubaena stat. rest., in Toussaint et al. (2019) M. lemnos is sister to M. arginussa . Although bootstrap values strongly support species branches, with values ranging from 96 to 99, values supporting the relationship between species are lower ( Fig. 9 ).

Distance analyses reveal that within species AED ( Table 1 ) are low in species of the “ arginussa ” species group, always below 1% and ranging from <0.001 to 0.007. The AED within specimens of M. pithyusa , the species with the largest range among species of the “ arginussa ” species group, calculated from 85 specimens from Mexico (Campeche, Oaxaca, Quintana Roo, Veracruz, and Yucatan states), Costa Rica (Alajuela, Heredia, Gunanacaste provinces), Peru (Loreto province), Brazil (Pará state), is 0.007 (standard error: 0.002). The name Anaea pithyusa morena Hall, 1935 , hitherto recognized as a valid subspecies of M. pithyusa , is represented in the analysis by a single specimen from Pará, Brazil, with a light brown phenotype similar to the type specimen from French Guiana. This specimen is recovered nested among specimens from Mexico, Central and South America, and thus the name is recognized as a synonym of Nymphalis pithyusa Felder, 1869 (syn. nov.). The light brown phenotype occurs in some, but not all, specimens of M. pithyusa from central and eastern Amazon, and it is usually sympatric with the typical greenish phenotype. The AED within specimens of M. perenna , calculated from three specimens from Mexico (Guerrero state) and El Salvador (Santa Ana and Ahuachapán departments), in the distribution of the nominal subspecies, is 0.007 (standard error: 0.002). Further analysis with the addition of specimens of the remaining subspecies of M. perenna , the trans-Andean South American M. perenna austrina ( Comstock, 1961) , and the closely related Venezuelan endemic M. paulus , should clarify the taxonomic status of those names, as Memphis lankesteri stat. rest., hitherto recognized as a subspecies of M. perenna , is here recognized as a separate species (see below). The AED within specimens of M. eubaena stat. rest., calculated from 14 specimens from Costa Rica (Alajuela, Guanacaste, Petén and Puntarenas provinces) and Ecuador (Carchi, Loja and Guayas provinces), is 0.004 (standard error: 0.002), and the AED within specimens of M. onophis stat. rest., calculated from 4 specimens from Peru (Cuzco and Junin deparments), Bolivia (La Paz department) and Ecuador (Morona-Santiago province), is 0.003 (standard error: 0.002). Both M. eubaena stat. rest. and M. onophis stat. rest. were previously recognized as subspecies of M. arginussa by Lamas (2004). The AED within M. arginussa, sensu Lamas (2004) (as a single species with three subspecies), is quite high, about 2% ( Fig. 9 ), thus supporting the recognition of three species instead of one. Memphis lemnos and M. neidhoeferi are recovered as quite cohesive species: the AED within specimens of M. lemnos , calculated from three specimens covering most of its distribution in Ecuador (Pastaza province), Peru (Huánuco department) and Brazil (Acre state) is 0.001 (standard error: 0.001), and the AED within specimens of M. neidhoeferi , calculated from 27 specimens from Mexico (Oaxaca and Veracruz states) and Costa Rica (Alajuela, Cartago, Guanacaste, and Putarenas provinces) is 0.002 (standard error: 0.001). There is no divergence between the two Panamanian specimens of M. smalli sp. nov. included in the analysis. AED within species could not be calculated for M. arginussa , M. herbacea and M. lankesteri stat. rest., because those species were represented on the analysis by single specimens; they are, however, quite distinct (at least by morphology) and rather localized species.

Between species AED ( Table 2) are high between species of the “ arginussa ” species group, ranging from 0.028 to 0.11, with the notable exception of the low AED between M. smalli sp. nov. and M. herbacea . The AED between M. perenna and M. lankesteri stat. rest., is 0.058 (standard error: 0.013), almost 6%, well above the threshold of 2% suggested as an appropriate threshold for species delimitation in Lepidoptera ( Hebert et al. 2003b) . Similar to M. herbacea and M. smalli sp. nov., M. perenna and M. lankesteri stat. rest. are another example where the southern Central American sibling species is very different in wing patterns from its northern sibling species (see Fig. 9 and Comstock (1961) plates). When wing patterns and distribution are considered, M. perenna and M. lankesteri stat. rest. are the reverse of the traits observed in M. herbacea and M. smalli sp. nov.: the Costa Rican M. lankesteri stat. rest., in the population nearest to the Panamanian M. smalli sp. nov., are lacking any sign of marginal spots and bands and occurs above 1000m ( DeVries 1987), while M. perenna is more widely distributed throughout Mexico and Central America, where it displays marginal light blue spots and bands on the upper side of both wings (see figures in Warren et al. 2016). The AED between pairs M. arginussa and M. onophis stat. rest. (0.05, standard error: 0.010), M. arginussa and M. eubaena stat. rest. (0.046, standard error: 0.009) and M. eubaena stat. rest. and M. onophis stat. rest. (0.028, standard error: 0.007) are well above the threshold of 2% suggested as an appropriate threshold for species delimitation in Lepidoptera ( Hebert et al. 2003b) , and each species form cohesive groups with low (<0.005) within species AED (see above). These species are somewhat distinct, but superficially similar in wing patterns as previously noted by Comstock (1961) and Pyrcz & Neild (1996). Nevertheless, the disjunct distribution of these species, M. eubaena stat. rest., occurring in Central America and trans-Andean South America, M. onophis stat. rest., occurring in western Amazon pre-Andean forests of South America, and M. arginussa , restricted to Atlantic forests of southeastern Brazil, combined with the AED between species pairs, supports the recognition of three separate species instead of three subspecies of a same species ( Braby et al. 2012). Lastly, the AED between two Panamanian specimens of M. smalli sp.nov. and the single Guatemalan specimen of M. herbacea is low: 0.005 (standard error: 0.003). This fact ensures that the systematic position of M. smalli sp.nov. can be firmly established within the “ arginussa ” species group, due to the close relationship with its sister species, M. herbacea . In fact, the barcodes of M. smalli sp.nov. and M. herbacea differ in only two base pairs. Nevertheless, the specific status of M. smalli sp. nov. is supported by morphology and distribution, as noted below.

Figures

FIGURE 9. Distance analysis inferred using Neighbor-Joining of specimens of the “arginussa” species group. Bootstrap values and branch lengths are shown above and below branches, respectively. Images: upper sides and undersides of Memphis smalli Riley & Dias sp. nov., M. herbacea (Butler & Druce, 1872), M. pithyusa (Felder, 1869), M. perenna (Godman & Salvin, [1884]), M. lankesteri (Hall, 1935), M. lemnos (Druce, 1877), M. eubaena (Boisduval, 1870), M. onophis (Felder & Felder, 1861), M. arginussa (Geyer, 1832), and M. neidhoeferi (Rotger, Escalante & Coronado, 1965), from top to bottom, not to scale. Photo credits: the authors, except M.eubaena and M. neidhoeferi, by K. Davis, M. Strangeland & A. Warren, and M. arginussa, by Senkenberg Museum für Tiekunde.

FIGURES 1–4. Memphis smalli Riley & Dias sp. nov. 1–2. Male holotype (USNM 283), dorsal and ventral, 3–4, Female allotype (USNM 274), dorsal and ventral. Scale bar = 1cm.