Golubtsov Alexander S, Korostelev Nikolai B, Levin Boris A
Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Moscow, Russia.
Papanin Institute for Biology of Inland Waters, Russian Academy of Sciences, Borok, Russia.
PLoS One. 2021 Jan 20;16(1):e0239639. doi: 10.1371/journal.pone.0239639. eCollection 2021.
The phenomenon of a massive vertebral deformity was recorded in the radiating Labeobarbus assemblage from the middle reaches of the Genale River (south-eastern Ethiopia, East Africa). Within this sympatric assemblage, five trophic morphs-generalized, lipped, piscivorous and two scraping feeders-were reported between 1993 and 2019. In 2009, a new morph with prevalence of ~10% was discovered. The new morph, termed 'short', had an abnormally shortened vertebral column and a significantly deeper body. This type of deformity is common in farmed Atlantic salmon and other artificially reared fish, but is rare in nature. In the Genale Labeobarbus assemblage, the deformity was present exclusively within the generalized and lipped morphs. The short morph had between seven and 36 deformed (compressed and/or fused) vertebrae. Their body depth was positively correlated with number of deformed vertebrae. In another collection in 2019, the short morph was still present at a frequency of 11%. Various environmental and genetic factors could contribute to the development of this deformity in the Genale Labeobarbus, but based on the available data, it is impossible to confidently identify the key factor(s). Whether the result of genetics, the environment, or both, this deep-bodied phenotype is assumed to be an anti-predator adaptation, as there is evidence of its selective advantage in the generalized morph. The Genale monstrosity is the first reported case of a massive deformity of the vertebral column in a natural population of African fishes.
在热那莱河（东非埃塞俄比亚东南部）中游的辐射状唇无须魮种群中记录到了大规模脊椎畸形现象。在这个同域种群中，1993年至2019年间报告了五种营养形态——广食性、有唇、食鱼性以及两种刮食性。2009年，发现了一种新形态，其出现率约为10%。这种新形态被称为“短体”，具有异常缩短的脊柱和明显更深的身体。这种畸形在养殖的大西洋鲑鱼和其他人工养殖的鱼类中很常见，但在自然界中很少见。在热那莱唇无须魮种群中，这种畸形仅出现在广食性和有唇形态中。短体形态有7至36个变形（压缩和/或融合）的椎骨。它们的身体深度与变形椎骨的数量呈正相关。在2019年的另一次采集样本中，短体形态的出现频率仍为11%。各种环境和遗传因素可能导致热那莱唇无须魮出现这种畸形，但根据现有数据，无法确定关键因素。无论这种深体表型是遗传、环境还是两者共同作用的结果，都被认为是一种反捕食者的适应特征，因为有证据表明它在广食性形态中具有选择优势。热那莱畸形是首次报道的非洲鱼类自然种群中大规模脊柱畸形的案例。
