Malacoscylus humilis var. fulvescens Gahan 1892: 271; Aurivillius 1923: 586 (cat.); Blackwelder 1946: 623 (checklist); Gilmour 1965: 633 (cat.).
Gahan (1892) described this species as a variety of Malacoscylus humilis based on three specimens from two places in Guerrero (Mexico). We know he had a male and a female because the original description provided a drawing of a female, and we have a photograph of a male (Fig. 5). Thus, the syntypes are not three females as reported by Monné (2020) and Tavakilian and Chevillotte (2020). Apparently, the male and female are not of the same species. The male antennomere III agrees better with that of Lamacoscylus humilis, while that of the female agrees very well with that of the species of Schmidarius. The general shape of the elytra does not agree well with that of L. humilis (proportionally narrower and longer, with posterior quarter not widened, and not distinctly rounded toward outer angle). Unfortunately, the photograph at our disposal does not allow further considerations. We propose a new rank and transfer this species to Schmidarius based on the drawing in the original description. For the moment, we prefer not to designate a lectotype for this species, as it would be necessary to examine all specimens identified as Malacoscylus humilis by Gahan (including the varieties) to know the sex and the true identity of each specimen, which at the moment is not feasible. In the case of lectotype designation, the specimen chosen should be a specimen with the antennomere III tumid, because Gahan (1892) figured this sex. As in several other cases, varieties have been considered as synonyms of the typical form or have been listed under the original species (e.g. Aurivillius 1923). Currently, according to ICZN (1999), the varieties need to be considered subspecies.