The enteric valve as a diagnostic character in Termites: taxonomic identification of species in the province of Chaco, Argentina.

Termites (Blattodea: Termitidae) play a fundamental role in ecosystems through nutrient recycling by decomposing lignocellulosic matter. Despite their ecological importance, identifying certain groups within the family, specifically the subfamily Apicotermitinae, remains a systematic challenge due to external morphological similarities and the frequent absence of the soldier caste. In this context, the enteric valve, a structure located at the transition between the midgut and the proctodeum (P2), constitutes a highly useful diagnostic character. Its high variability in architecture, shape, and internal ornamentation allows for precise discrimination between genera and species. This study employed dissection and mounting techniques for this structure to facilitate species identification within the province of Chaco, Argentina. Using stereoscopic magnifiers, the digestive tract of the specimens was extracted, and transverse cuts were made in the posterior region of the first segment of the proctodeum (P1) and in the anterior region of the third segment (P3). After removing the intestinal contents, a longitudinal cut and an extension of the area were performed. The valves were mounted in glycerin for analysis under optical microscopy, evaluating the diversity of their structures. The results allowed for the rigorous identification of Anoplotermes pacificus, Aparatermes abbreviatus, and Aparatermes cingulatus based on differences in valvular morphology. Our results support the use of the enteric valve (P2) as a high-resolution taxonomic character for Apicotermitinae and highlight the importance of implementing precise dissection techniques to document the biodiversity of Termitidae, providing valuable data for the systematics of these insects in Neotropical ecosystems.