Subterranean Fishes of the World

6934

2024

Garra longipinnis is a cyprinid freshwater fish endemic to Northern Oman and the UAE. Despite the harsh climatic conditions, this taxon is quite common and inhabits all kinds of water bodies available in this area. The particular interesting thing about this species is that, in addition to the many surface populations, one troglomorphic cave population is known inhabiting the Al Hoota cave in the midst of the Hajar mountains. We investigated the population structure between the cave and nearby surface populations by analyzing variable microsatellite markers. The results clearly show that the cave population is genetically isolated and gene flow can be detected only scarcely and unidirectional from the cave to the surface populations. Besides, phenotypic plasticity (exposure to light) seems to play an important role when it comes to the degree of troglomorphic traits (pigmentation, eye size). To further study the effects of light exposure on the phenotype, we conducted breeding experiments under controlled light regimes. We will employ histological analysis and μCT scans to compare the degree of degeneration between specimens reared under different light regimes from both morphotypes and different developmental stages. Further on, in the course of an extensive phylogeographic framework, we investigated the genetic diversity of Garra specimens from the Northern Oman including samples from 56 sampling sites. We received concordant results from analyzing three mt markers as well as 18 nc microsatellite markers which show five genetically and geographically clearly differentiated groups, which we subsequently address as distinct species from different geographic regions. However, the cave population belongs to the same species as the nearby surface populations, specifically Garra longipinnis. Garra from northern Oman is currently listed as “Least Concern” (IUCN Red List). Hence, the newly discovered Garra species-complex in northern Oman is in urgent need for reevaluation, as desertification, habitat destruction as well as water shortage and potential chemical pollution pose serious threats to organisms occupying extreme habitats. A Species description for the newly discovered taxa was conducted and will provide the basis for a conservation reassessment

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26th International Conference on Subterranean Biology and 6th International Symposium on Anchialine Ecosystems: Cagliari 9-14 Sept 2024