Metiscus atheas Godman, 1900

Zhang, Jing, Cong, Qian, Shen, Jinhui & Grishin, Nick V., 2022, Taxonomic changes suggested by the genomic analysis of Hesperiidae (Lepidoptera), Insecta Mundi 2022 (921), pp. 1-135 : 76-78

Metiscus atheas Godman, 1900 is a valid species

Currently considered a junior subjective synonym of Hesperia achelous Plötz, 1882 (type locality Panama: Chiriqui), Metiscus atheas Godman, 1900 (type locality Mexico: Tabasco, Guatemala: Coban, Costa Rica : Caché, Panama: Chiriqui, Brazil: Amazonas, Trinidad) does not conform to what is known about H. achelous . Metiscus atheas is characterized by dark-brown typically unspotted wings and a diagnostic shape of stigma, which is bipartite and rather broad—compare to Lychnuchus (Enosis) immaculata (Hewitson, 1868) —as illustrated in the original description ( Godman and Salvin 1900b).

We reviewed information available about H. achelous . No type specimens of H. achelous are known to exist, and the original description given in a form of identification key is too brief to confidently identify this species ( Plötz 1882a): “forewing darker in the middle area below” is the only species-specific information provided, in addition to forewing length of 16 mm and the drawing number 260. These unpublished Plötz drawings, now presumed lost, were inspected by Godman (1907) who organized copying those he could not readily match to species known to him. The drawings 258–265 relevent to this discussion were not among the compilation of these copies now in the library of the Natural History Museum, London (inspected by N.V.G), and Godman (1907: 137) noted that Hesperia paria Plötz, 1882 (type locality Panama: Chiriqui, Plötz drawing 259), currently in Eutychide Godman, 1900 , was synonymous with H. achelous .

While it may seem odd that the two taxa placed next to each other (drawing numbers 259: H. paria and 260: H. achelous ) by Plötz, and thus directly compared with each other, are synonymous, it is not without a precedent. For instance, Hesperia perloides Plötz, 1882 (type locality Brazil, drawing number 282) and Hesperia perla Plötz, 1882 (type locality Brazil: Rio de Janeiro, drawing number 283) are currently treated as synonyms ( Mielke 2005).

The names H. achelous and H. paria were proposed in the same work issued on the same date ( Plötz 1882a), and the precedence between the two names was determined by the “First Reviser” (ICZN Code Art. 24.2). By placing the name Eutychide achelous in the right column without comments, and Hesperia paria in the left column, Godman (1907: 137) seemingly gave priority to the name H. achelous over H. paria . This is because in all instances where the name given in the left column has priority, Godman’s text in the right column explicitly stated that priority ( Godman 1907). If this priority designation is questioned, Draudt (1923b) also used E. achelous as a valid name and listed “= paria ” as its synonym, probably following Godman. Therefore, if considered synonymous, H. paria would be a junior subjective synonym of H. achelous .

Furthermore, Godman (1907: 137) commented that the specimen illustrated by Plötz in the drawing number 259 as H. paria was “from La Guayra, not Chiriqui ” as stated in the original description ( Plötz 1882a). A number of possibilities arise here, one being that a mistake was made in listing the locality of H. paria as “ Chiriqui ” in the Plötz description. In agreement with that, Draudt (1923b) listed both Panama and Venezuela as the localities for his entry “ E. achelous Plötz (= paria Plötz )”.

In addition to the analysis of Plötz drawing, the identity of H. achelous was based on the specimens identified as such from the Staudinger collection ( Godman and Salvin 1900a), now in the ZMHB. Type specimens for a large number of Plötz names are in the Staudinger collection and it is possible that these H. achelous specimens were the Plötz types, although not labeled as such. Inspecting these specimens, Godman concluded that H. achelous is the species known today as Eutychide paria following Evans (1955). In the ZMHB Hesperiidae drawer 183, there was a male specimen (July 2012, inspected and photographed by N.V.G.) that would be identified as Evans’ H. paria with a green label “achelous / Plötz” above it.

Evans (1955) disagreed with the application of H. achelous for H. paria by Staudinger ( Godman and Salvin 1900a), Godman (1907), and Draudt (1923b). Evans used Eutychide paria as the name for this species and synonymized M. atheas under his Enosis achelous . The reasons behind this disagreement and placement of M. atheas in synonymy with H. achelous were not given ( Evans, 1955: 216), remain unsubstantiated, and are unclear to us. Based on the analysis presented above, we do not follow Evans, remove Metiscus atheas Godman, 1900 from synonymy, and consider it to be a valid species, which is the type species of Metiscus Godman, 1900 by monotypy. To promote the stability of nomenclature and to narrow down the type locality currently spanning both Americas, N.V. G. hereby designates the male specimen in the collection of the Natural History Museum, London, UK whose genitalia and wing venation were illustrated in the Godman and Salvin book (1900b), as the lectotype of Metiscus atheas Godman, 1900 . The lectotype is from Mexico: Tabasco, Teapa, collected by H. H. Smith. Its left wings are cleared from scales to reveal venation and stigma, and genitalia are prepared on a mini-slide pinned together with its labels. According to Selander and Vaurie (1962), the type locality Teapa is 48 km south of Villahermosa (very near the border with Chiapas), approximate GPS coordinates 17.55, −92.95.

The identities of H. achelous and H. paria remain to be determined after a more careful search for its possible type specimens we have initiated in several collections is conducted. There are three issues with finalizing the application of the names H paria and H. achelous . First, the forewing length of H. achelous given by Plötz (1882a) in the original description is 16 mm (vs. 18 mm for H paria ), which is smaller than typical for the species Evans (1955) called H. paria (20 mm) and Godman called H. achelous . Second, our argumentation presented above is based on three publications ( Godman and Salvin 1900a; Godman 1907; Draudt 1923b) that may not be fully independent and could largely stem from the specimens that Staudinger identified as H. achelous . The argument breaks down if Staudinger misidentified these specimens and other sources simply followed this misidentification, and Plötz’s drawings 259 and 260 were not detailed enough or misleading to offer clues about the true identity of these species as interpreted by Godman. Third, the La Guaira specimens from the collection in Greifswald, given as Plötz’s place of residence in the original publication ( Plötz 1882a) should be investigated to address the discrepancy between the locality of H. paria on the drawing (La Guaira) ( Godman 1907: 137) and in the description (Chiriqui). The collection of Ernst Moritz Arndt Universität in Greifswald, Germany has been reported to contain a number of Plötz’s type specimens from La Guaira, some of which have been designated as lectotypes ( Mielke and Casagrande 2002).

Presently, in the interest of nomenclature stability we treat Hesperia achelous as a nomen dubium, because current evidence points to synonymy between H. achelous and H. paria , which results in H. achelous being a valid name, instead of H. paria . Implied usage of H. achelous for the species currently known as E. paria may need revision after the identity of H. achelous is determined, a change that better be avoided. Therefore, we leave the application of the name E. paria as currently used, following Evans (1955).