Strigoderma villosella ( Blanchard, 1851 )

Madrigal, Kevin, Zaragoza-Caballero, Santiago & Ramírez-Ponce, Andrés, 2023, Comparative morphology of the genera with perpendicular parameres in Anomalini (Coleoptera, Scarabaeidae, Rutelinae) allows revalidation of the endemic Mexican genus Lamoana Casey, 1915 stat. rev., European Journal of Taxonomy 910, pp. 175-199 : 176-177

Taxonomic history of Strigoderma villosella ( Blanchard, 1851)

Historical taxonomic records are fundamental and pivotal tools to any taxonomic work, as they form a link between past ideas and modern changes ( Gravina et al. 2020). For that reason, it is important to take a brief look at the historic background of S. villosella so we can understand its present condition and justify our decisions.

Blanchard (1851) originally described S. villosella in the genus Phyllopertha . The information given by this author is somewhat simple and lacks certain important information such as the precise type locality and male genitalia. Bates (1888) made the first change to the genus Anomala , arguing that the legs were more robust than those of other species of Phyllopertha . In that study, Bates also described Strigoderma presidii but saw that its mesepimera did not rise near the elytral humeri, so he proposed that it might belong to Anomala . Nonfried (1893) made the revision of the genera Epectinaspis and Strigoderma , and described S. hirsuta . Casey (1915) established Lamoana , a monospecific genus created for A. villosella . Casey’s observations were quite complete, considering the standards of that time, but he did not make a morphological comparison of the male genitalia. It must be said that the specimens that Casey evaluated came from a different locality than those that Bates and Blanchard studied, so it is uncertain whether they belonged to the same species or not. Ohaus (1918) synonymized S. hirsuta with A. villosella and retained it in Anomala . This nomenclatural change was made without considering all the morphological criteria that Casey established for this taxon three years earlier. We must say that there is no explanation why Ohaus ignored Casey’s decision.

In 1944, Blackwelder published a checklist of beetles of Mexico, Central America, South America, and the West Indies. In this study, he retained the synonymy between A. villosella – S. hirsuta and recognized Lamoana as a subgenus. Almost 50 years later, Bader (1992) redescribed S. presidii and made several notes about its position. He remarked on the similarity of A. villosella with S. teapensis Bates, 1888 and S. presidii in both general habitus and the shape of the male genitalia and noted that the latter presented an intermediate morphological condition between Strigoderma and Anomala , arguing that it must be placed in a new genus or be changed to Anomala . Ramírez-Ponce & Morón (2009) made a phylogenetic study to evaluate the relationships between the genera of Anomalini . They concluded that the principal difficulty in delimiting genera with precision within the tribe was that some of genera had been established on questionable criteria. They revalidated Pachystethus ; demonstrated the paraphyly of Callistethus ; validated the synonymy between Anomalacra Casey, 1915 and Paranomala ; revalidated Paranomala , and thus A. villosella was transferred to Paranomala . Some years later, Ramírez-Ponce (2012), studied the supraspecific systematics of Paranomala , and found that P. villosella was near to the Strigoderma-Epectinaspis clade, so he decided to place it in Strigoderma . Notwithstanding his decision, he remarked on the similarity in terms of male genitalia to some species of Epectinaspis and Balanogonia , just as Paucar-Cabrera had in 2003.

In recent studies, the internal and external morphology have been carefully compared among the genera of Anomalini , which has allowed us to recognize patterns of variation and homologies at different levels, thus proposing taxonomic arrangements within the tribe, finding that the parameres in a perpendicular position with respect to the tectum presented in Strigoderma villosella , is shared with the genera Balanogonia , Callirhinus , Dilophochila , Moroniella and Mazahuapertha ( Morón & Ramírez-Ponce 2012; Ramírez-Ponce 2012, 2015). An overall comparative study of male genitalia within these genera has led us to recognize clear differences in Strigoderma villosella thus reinforcing the evidence for revalidating the genus Lamoana .