COI-based species delimitation reveals the taxonomic status of two recently described Latrodectus species from Colombia (Araneae: Theridiidae)

The comb-footed spider genus Latrodectus Walckenaer, 1805 comprises some of the most medically important spider species due to the potent neurotoxic action of their venom. Despite this relevance, few studies have examined the distribution and presence of Latrodectus in Colombia. Recently, two new species were described from this country based on COI molecular data: Latrodectus hurtadoi Rueda & Realpe, 2021 and Latrodectus garbae Rueda & Realpe, 2021.

However, these species lack consistent diagnostic morphological characters and exhibit genetic divergences of ~2%, a level commonly surpassed by intraspecific variation reported in other araneomorph spiders, raising doubts about their taxonomic validity. To assess their status, we reconstructed the phylogeny of Latrodectus using 329 COI sequences representing multiple species obtained from GenBank, including those used in the original descriptions.

We applied tree-based (PTP and mPTP) and genetic-distance-based (ASAP) species delimitation methods. Our analyses suggest that L. hurtadoi is likely a valid species within the broader L. hesperus Chamberlin & Ivie, 1935 lineage, a widespread North American taxon that may itself represent a species complex. In contrast, L. garbae is genetically indistinguishable from the Argentine species L. corallinus Abalos, 1980.

Therefore, we consider Latrodectus garbae a junior synonym of L. corallinus. These findings highlight the need for integrative taxonomic approaches to Colombian Latrodectus species, which will ultimately improve species identification and the clinical management of envenomation cases.