Rediscovery of synanthropic silverfish Ctenolepisma calvum (Ritter, 1910) (Insecta: Zygentoma: Lepismatidae: Ctenolepismatinae) from Kerala, India and assignation of European C. calvum to a new species

Ctenolepisma calvum (Ritter, 1910) (Zygentoma: Lepismatidae: Ctenolepismatinae) was first described with two pairs of styli by Ritter on the basis of specimens from Sri Lanka found in houses. Recent records of synanthropic populations of Ctenolepisma Escherich, 1905 with similar habitus were attributed to this species and redescribed as bearing only one pair of styli, interpreting Ritter’s reference to the number of styli as erroneous. However, a species of silverfish from Kerala, India, has been found that matches Ritter’s description of C. calvum in terms of morphological characters and is genetically different from the lineages of European Ctenolepisma previously attributed to C. calvum. Thus, the specimens from Europe studied by Molero-Baltanás et al. (2024a) as C. calvum are assigned to a new species, C. phantasma Molero-Baltanás, Raphel, Mitchell & Jose, n. sp. Ctenolepisma calvum is the tenth species in the genus Ctenolepisma reported from India. A detailed morphological redescription of this species is presented in this paper, together with its differences from C. phantasma Molero-Baltanás, Raphel, Mitchell & Jose, n. sp. recorded in Europe and Japan, and molecular sequences of the authentic C. calvum.