Hesperia pruinosa Plötz, 1882

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 : 83-84

Hesperia pruinosa Plötz, 1882 is a junior objective synonym of Dion uza ( Hewitson, 1877)

The original description of Hesperia pruinosa Plötz, 1882 (type locality South America) states that its ventral hindwing is dusted with violet-gray for more than 1/2 towards the anal angle, lists the forewing length at 20 mm, and gives the illustration number 293 ( Plötz 1882a). While this illustration (likely lost) was not included in the Godman’s copy of Plötz drawings now in the Natural History Museum, London, UK (inspected by N.V.G.), Godman (1907: 138) noted the two specimens in the Godman and Salvin collection from [ Brazil, Mato Grosso] Chapada belong to this species. Inspection of these two specimens in Natural History Museum, London, UK, also mentioned by Evans (1955) revealed that instead of ventral hindwing being “über 1/2 gegen den Hinterwinkel veilgrau bestäubt” per Plötz description, it has a discal band of pale-blue spots encircled with brown. Moreover, these specimens are smaller than the H. pruinosa type (s): forewing length under 18 mm instead of 20 mm, so they are not a perfect match to the description of H. pruinosa .

However, the Draudt illustration of H. pruinosa ventral aspect on plate 189 row e image 5 agrees with the original description better that the Chapada specimens ( Draudt 1923b). Due to general resemblance between Draudt illustrations and Plötz illustrations copied by Godman’s decision, it is likely that a number of Draudt illustrations were either drawn from Plötz’s original illustrations or specimens used by Plötz. Therefore, the Draudt H. pruinosa illustration is a likely representation of the type specimen. Out of specimens we examined, this illustration comes closest to the lectotype of Hesperia uza Hewitson, 1877 (type locality not stated). In particular, both the specimen and illustration have a broad lavender area on ventral hindwing covering cells M 1 -M 2 and M 2 -M 3 and partly discal cell, discal blue spots are poorly defined (widened, merged with the background, noticeable upon more careful inspection as areas of blue/greener shiny scales), “replaced” by a row of brown spots, not as distinct on the specimen as on the illustration.

As far as we can tell, the name H. uza was not mentioned by either Plötz or Draudt, but its original description is nearly the same as H. pruinosa ’s: “the outer margin of the anterior wing and more than the outer half of the posterior wing are lilac-white” ( Hewitson 1877). It is likely that Plötz was not aware of H. uza . Because Plötz worked with many specimens from the Staudinger collection, now in the ZMHB, that contains many of his type specimens, he may have used this particular specimen to describe H. pruinosa . Therefore, it is possible that the H. uza lectotype is also a syntype of H. pruinosa . However, it seems to be nearly impossible to demonstrate it convincingly.

We conducted a careful search for H. pruinosa syntypes in all (more than 250) Hesperiidae drawers in the ZMHB, all Hesperiidae boxes in ZSMC and the Hesperiidae collection in EMAU (collections known to hold Plötz type material) and did not find any specimens that agree with the original description of H. pruinosa . Therefore, its types are either lost or unrecognizable, and we proceed with a neotype designation. There is an exceptional need to designate the neotype because this name has been arbitrarily assigned, causing inconsistency and thus confusion ( Evans 1955; Mielke and Casagrande 2002), and the lack of the name-bearing type of H. pruinosa prevents definitive taxonomic studies of this group, stimulated by genomic sequencing that revealed the presence of two species. It is essential to define the name objectively and in a manner that is consistent with the intent of the original author, if it does not undermine stability of nomenclature.

The specimen, previously designed as the lectotype of Hesperia uza Hewitson, 1877 by Mielke and Casagrande (2002), who gave label data for it, is hereby designated by N.V.G. as the neotype of Hesperia pruinosa Plötz, 1882 , making the two names objective synonyms. This specimen, pictured on the Butterflies of America website ( Warren et al. 2016), bears two additional labels added since, both white, printed: || [barcode image] http://coll.mfn-berlin.de/u/ | 44a0ce|| and || DNA sample ID: | NVG-18052D10 | c/o Nick V. Grishin ||, and can be recognized by a unique wing tear from the outer margin along 1A+2A vein on the right hindwing. The neotype is in the Museum für Naturkunde, Berlin, Germany (ZMHB). The neotype is designated to clarify the taxonomic status of H. pruinosa , which is differentiated from other taxa by the characters stated in the original description ( Plötz 1882a), and in Draudt (1923b), as discussed above. This neotype agrees with what is known about H. pruinosa . The collecting locality of the neotype is currently unknown and will be determined by genomic comparison with specimens from known localities. However, its phenotype is consistent with the neotype being from South America (the type locality of H. pruinosa ), for example, from Colombia. Colombian specimens of this species in the BMNH collection are particularly large and are characterized by broadly-lavender ventral hindwings without a discal band of brown-framed blue spots.

In this work, we placed taxa discussed in this section in Dion Godman, 1901 (type species Carystus gemmatus Butler, 1872 ). And as a result of our studies, the taxon Evans (1955) called Enosis pruinosa pruinosa became Dion uza , and Enosis pruinosa agassus became Dion agassus .