Critically Endangered
Unio tumidiformis
Unio tumidiformis
Unio tumidiformis is a bivalve in the family Unionidae (order Unionida), recorded as Critically Endangered.
Appearance
Unio tumidiformis grows to a shell length of 57 mm (2.2 in) and wet weight of 16 g (0.56 oz).
Range and habitat
Unio tumidiformis occurs in temporary Mediterranean-type streams, surviving the dry season in pools that do not dry up. It is endemic to the southwestern Iberian Peninsula. Existing populations are known from the Guadiana, Mira, and Sado Rivers in Portugal and Spain.
Pins are Wikidata “endemic to” fields. Orange dots, when present, are GBIF occurrence tiles — survey bias included.
Breeding
Freshwater mussels bury in the bed and live for decades if the river still runs and the host fish still spawn.
In crisis
Populations from the Guadiana and Guadalquivir River basins have already been extirpated. This species is threatened by changes of hydrologic regime of the streams, natural droughts, gravel and water extraction, dams, and impoundments. Also the loss of suitable host fish and pollution are threats.
Unio tumidiformis is Critically Endangered on this catalog because that is the IUCN category stored on Wikidata. Confirm the official criteria and any later count on iucnredlist.org.
Sources
Written for this catalog from the English Wikipedia article on Unio tumidiformis, Wikidata item Q14753696. Family and order context is original field-guide writing about the group, not a copied assessment of this one species. Wikipedia text is CC BY-SA. Not an IUCN assessment. Counts, when quoted, can change — confirm them on the recovery programme and on iucnredlist.org.



