Genomic and morphological assessment of the status of Kuenzler's hedgehog cactus (Echinocereus fendleri var. kuenzleri)
Beck, J.B., Fehlberg, K.M. & Fehlberg, S.D. Genomic and morphological assessment of the status of Kuenzler's hedgehog cactus (Echinocereus fendleri var. kuenzleri). Conserv Genet (2023). https://doi.org/10.1007/s10592-023-01527-0
Fendler's hedgehog cactus (Echinocereus fendleri) is a morphologically variable species distributed across four U.S. states (AZ, CO, NM, TX) and the Mexican states of Sonora and Chihuahua. Some authors recognize a single, variable species, while others recognize up to four intraspecific taxa. This uncertainty carries conservation implications for E. fendleri var. kuenzleri (Kuenzler's hedgehog cactus), which is listed as Federally threatened. The goal of the study was to examine genomic and morphological variation in Echinocereus fendleri to determine relationships among the three varieties primarily distributed in the United States, specifically focusing on the status of Kuenzler's hedgehog cactus. Analyses of a double-digest restriction site-associated DNA sequence (ddRADseq) dataset indicated a well-supported E. fendleri clade. Within this clade, populations of E. fendleri var. rectispinus form a paraphyletic grade, with some sister to a well-supported clade containing all E. fendleri var. fendleri and E. fendleri var. kuenzleri. Three subclades are apparent within the E. fendleri var. fendleri/kuenzleri clade- a northern clade comprising E. fendleri var. fendleri, a central clade comprising E. fendleri var. fendleri and E. fendleri var. kuenzleri from Lincoln Co., NM, and a southeastern clade comprising two populations of E. fendleri var. kuenzleri. Trivariate analyses of morphological data establish three relatively distinct clusters of populations that correspond to the three focal varieties. These results establish that although each E. fendleri variety is morphologically distinct, none of them correspond to a single evolutionary lineage. The approach to conservation of E. fendleri var. kuenzleri should be re-evaluated, and three alternatives are discussed.