Data from: The fossil record and phylogeny of the auklets (Pan-Alcidae, Aethiini)

The auklets Aethia and Ptychoramphus comprise the smallest known Alcidae (Aves, Charadriiformes) and have a fossil record that extends into the Miocene. The evolution of auklets is poorly understood because systematic hypotheses of relationships among extant auklets are largely incongruent, the morphology of auklet fossils has not been evaluated in detail, and extinct species of auklets have not been previously included in a phylogenetic analysis. Previously described auklet fossil remains are reviewed and two new species of auklet, Aethia barnesi and Aethia storeri, are described from the Miocene and Pliocene of southern California, USA. Previously described auklet fossil remains, the two newly described extinct species of auklet, and extant species of auklets and other alcids are included in combined phylogenetic analyses of morphological and molecular sequence data. Based on the results of the phylogenetic analyses, the taxonomy of fossils referred to Aethiini is revised and the evolution of the clade is evaluated in a phylogenetic context. The osteological morphology of extinct auklets appears to be little-changed from their extant relatives, suggesting that the ecological attributes of these small wing-propelled divers may also be relatively unchanged since the Miocene.凤头海雀属（Aethia）与扁嘴海雀属（Ptychoramphus）类群隶属于已知体型最小的海雀科（Alcidae，鸟纲Aves，鸻形目Charadriiformes），其化石记录可追溯至中新世时期。目前学界对海雀类的演化认知仍较为匮乏，原因在于：现生海雀类之间的系统发育关系假说存在大量不一致之处，海雀化石的形态学特征尚未得到细致评估，且此前的系统发育分析均未纳入已灭绝的海雀物种。本文对此前已发表的海雀化石遗存进行了系统梳理，并基于美国加利福尼亚州南部的中新世与上新世地层，记述了两个海雀新种：巴恩斯凤头海雀（Aethia barnesi）与斯托勒凤头海雀（Aethia storeri）。研究将此前发表的海雀化石遗存、本次新记述的两种已灭绝海雀，以及现生海雀类与其他海雀科物种一同纳入形态学与分子序列数据的联合系统发育分析。基于系统发育分析结果，本文对归入海雀族（Aethiini）的化石类群的分类学进行了修订，并在系统发育框架下对该演化支（clade）的演化历程开展了探讨。已灭绝海雀的骨骼形态与现生近缘类群几乎无显著差异，这表明这类依靠翅膀推进的小型潜水海鸟的生态特征自中新世以来也相对保守。