The trophic role of cave shrimps of the genus Typhlatya seen through stable isotope eyes

With the aim of describing the isotopic niche of the anchialine shrimps of the genus Typhlatya from the Yucatan Peninsula (YP) we analyze a dataset that includes three of the four species present in the region using published and new δ 13 C and δ 15 N values. Typhlatya shrimps are recognized as ecologically important in the anchialine food web due to their ample distribution, relatively high abundance and feeding characteristics. The variation in δ 13 C values shows that Typhlatya shrimps cover almost the complete interval of the whole anchialine community reflecting the different nutrient sources they can feed on; the three species separately have δ 13 C ranges that partially overlap, becoming more negative starting with T. mitchelli , followed by T. dzilamensis and T. pearsei . The δ 13 C ranges for T. mitchelli and T. pearsei from four cenotes did not change between the rainy and dry seasons. By region, the δ 13 C ranges for the whole anchialine community in the Ring of Cenotes are narrower and less negative than those from the Caribbean Cave Area, reflecting the different geomorphology and hydrology of the two regions. The isotopic niches of T. mitchelli and T. pearsei , the two dominant species in the freshwater lens, overlap around 20% leaving an ample margin for coexistence. Typhlatya pearsei has the most negative δ 13 C values which are consistent with feeding on microbial biomass, including methanotrophic bacteria. The isotopic niches of the three Typhlatya species studied although somewhat variable, are well defined and compose a well structured community.