ABSTRACT
The hypogean fauna from El Hierro includes 19 troglobites, many of them belonging to genera also represented in La Palma by vicariant species. The cockroach Loboptera ombriosa is the most widespread troglobite in the island, showing a cline of morphological adaptations from big, red-brown individuals in the north to smaller yellowish ones in the extreme south. Distributional patterns of other species also indicate differences between the El Golfo area at the northwest covered by humid forests, and the rest of the island with pine forest and drier bushland. Three ambimorph ground beetles of the genus Licinopsis are found: L. picescens in caves and MSS of El Golfo, and L. obliterata and the more adapted L. schurmanni in the rest of El Hierro. The most troglomorphic animal on the island is the thread-legged bug Collartida anophthalma, a relict belonging to a genus from Central and Eastern Africa with the only troglobites on the Canary Islands. The aquatic fauna is scarce and limited to brackish interstitial waters, where two amphipod crustaceans have been found: Pseudoniphargus salinus and Ingolfiella canariensis.
