Gerosis cnidus (Plötz, 1884)

Zhang, Jing, Cong, Qian, Shen, Jinhui, Song, Leina & Grishin, Nick V., 2024, Taxonomic advances driven by the genomic analysis of butterflies, The Taxonomic Report of the International Lepidoptera Survey 11 (7), pp. 1-43 : 32-33

Gerosis cnidus (Plötz, 1884) is a species distinct from Gerosis phisara (Moore, 1884) , with revised synonymy

Inspecting Hesperiidae holdings in MFNB, we found a syntype of Achlyodes cnidus Plötz, 1884 (type locality not specified), currently regarded as a junior subjective synonym of Gerosis phisara (Moore, 1884) (type locality in India: Assam, Khasi Hills). According to its labels ( Fig. 26b), this specimen shown in Fig. 26a was identified as cnidus by Plötz (“best[immt]. v[on]. Plötz”). This identification label was added to the specimen before the publication because it cited an unpublished name (“i[n]. l[itteris]”). The specimen is from the Weymer collection that contains primary types of many of Plötz’s names. The specimen agrees with the original description and Godman’s copy of the unpublished illustration by Plötz ( Fig. 26c). Because this is a rarely encountered phenotype of Gerosis , it is possible that it was the only specimen known to Plötz, and the specimen illustrated. Godman’s copies appear rather sketchy and not particularly detailed (it remains unclear whether the originals were more detailed), and the agreement between the illustration ( Fig. 26c) and the specimen ( Fig. 26a) is reasonable.

To stabilize nomenclature, N.V.G. hereby designates the specimen in MFNB shown in Fig. 26a, a male, bearing the following five rectangular white labels, 3 rd and 5 th printed, others handwritten: [cnidus NVG-21115E07 | c/o Nick V. Grishin ] as the lectotype of Achlyodes cnidus Plötz, 1884 . The lectotype has a fingerprint mark at the left forewing apex and is missing a part of the right hindwing fringe towards the tornus. The number 161 likely refers to the Weymer collection, and we were not able to associate it with any published information. The label 75:5 gives a genus number (75 - Gindanes ) and a species number (5 - cnidus ) in the Mabille catalog ( Mabille 1903) that was used as a guide to arranging the Hesperiidae collection in Berlin. The type locality that was not specified in the original description and not given on the lectotype labels remains unknown and will eventually be deduced by genomic sequencing and comparison with G. cnidus specimens from known localities.

Genomic sequencing of the A. cnidus lectotype does not place it close to G. phisara but instead revealed that it is distant from other Gerosis Mabille, 1903 (type species Coladenia hamiltoni Nicéville, 1889 , currently treated as a junior subjective synonym of Satarupa phisara (Moore, 1884) ( Fig. 27). Therefore, we propose that Gerosis cnidus (Plötz, 1884) , stat. rest. is a valid species distinct from Gerosis phisara (Moore, 1884) in particular, and from other Gerosis in general. Because we sequenced only one specimen of Gerosis cnidus , it remains unclear whether its unique for Gerosis wing pattern is an aberration as suggested by Evans (1949) or a color morph (in which case the typical striped and spotted form has not been found yet), or represents the typical (and the only?) wing pattern form of this species.

Although we have not sequenced type specimens of Coladenia hamiltoni Nicéville, 1889 (type locality in Bangladesh: Sylhet) and Caprona? kuki Tytler, 1915 (type locality in India: Lushai Hills), due to their wing pattern similarity with G. cnidus , we propose to treat them as its junior subjective synonyms instead of keeping them as synonyms of Gerosis phisara , pending further research. As a result of this analysis, the valid name for the type species of Gerosis becomes Gerosis cnidus (Plötz, 1884) , stat. rest., and we hypothesize that its type locality is in eastern India or Bangladesh. If the wing pattern of G. cnidus represents an unusual color morph, this morph may be present in other species of Gerosis , in which case C. hamiltoni and/or C. kuki might be some species other than G. cnidus .