In the absence of any prior comprehensive analysis, I evaluate divergence along the biotope axis in the habitat stage of the evolutionary radiation of Antarctic cryonotothenioids. I utilize the available percentage buoyancy (% B ) measurements as habitat proxies for recognition of the pelagic, semipelagic, demersal, and benthic biotopes that include, respectively, 5%, 10%, 73%, and 12% of the 59 species and 1749 specimens in the study. The majority of species retain the ancestral demersal biotope of Eleginops maclovinus , and this probably enhances ecological plasticity. Divergence into the pelagic biotope is the most distinctive organismal feature of the radiation and, although only 5% of species are pelagic, this biotope is not depauperate in global comparisons. Pelagic or potentially pelagic species are Dissostichus mawsoni , D. eleginoides , Pleuragramma antarctica , Aethotaxis mitopteryx , and Gvozdarus svetovidovi . Small ontogenetic changes in % B with growth are typical; however, this is extensive in D. mawsoni , a species with the potential to transition through benthic to pelagic biotopes over ontogeny. Occupation of the pelagic biotope by large D. mawsoni may be impermanent as it is lipid-dependent, a contingency reliant on the availability of P. antarctica as prey. In unusual conditions, the specialized sacs of P. antarctica can also yield their lipid for metabolism with possible loss of buoyancy. Pelagic species are inordinately important in the food web. In the southwestern Ross Sea a guild of large mammalian and avian predators, which includes D. mawsoni , is reliant on lipid-rich, energy-dense cryonotothenioid prey. This includes asymmetrical intraguild predation on D. mawsoni , with P. antarctica as a basal resource for the guild.

中文翻译：

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基于浮力的南极冰冻鱼进化辐射的生物群落轴

在没有任何事先综合分析的情况下，我评估了南极低温植物进化辐射栖息地阶段沿生物群落轴的分歧。我利用可用的百分比浮力 (% B ) 测量值作为栖息地代理识别远洋、半远洋、底层和底栖生物群落，分别包括 59 种和 1749 种的 5%、10%、73% 和 12%研究中的标本。大多数物种保留了 Eleginops maclovinus 的祖先底层生物群落，这可能增强了生态可塑性。进入远洋生物群落是辐射最独特的生物特征，虽然只有 5% 的物种是远洋生物，但在全球比较中，这种生物群落并没有枯竭。远洋或潜在的远洋物种是 Dissostichus mawsoni , D. eleginoides , Pleuragramma antarctica、Aethtaxis mitopteryx 和 Gvozdarus svetovidovi。% B 随生长而发生的小的个体发育变化是典型的；然而，这在 D. mawsoni 中很广泛，这种物种有可能通过个体发育从底栖生物群落过渡到远洋生物群落。大型 D. mawsoni 占据远洋生物群落可能是无常的，因为它是脂质依赖性的，这是依赖于 P. antarctica 作为猎物的偶然性。在不寻常的条件下，P. antarctica 的特化囊也可以产生用于代谢的脂质，但可能会失去浮力。远洋物种在食物网中极其重要。在罗斯海西南部，包括 D. mawsoni 在内的大型哺乳动物和鸟类捕食者行会依赖于富含脂质、能量密集的冷冻类动物猎物。这包括对 D 的不对称公会内捕食。