ABSTRACT

The Miocene fossil fish †Pentaceros sakhaliniсus Gretchina, 1975, (Perciformes, Pentacerotidae) is redescribed based on the holotype and numerous additional materials collected on Sakhalin Island (western Pacific, Russian Far East) at the end of the 20th century. The general appearance and body proportions, as well as the presence of multiple (more than three) anal-fin spines, make the Miocene taxon similar to members of the family Pentacerotidae, whereas generalized morphological characters such as the presence of three supraneurals and the absence of rugosity of the superficial head bones differentiate this species greatly from any known pentacerotid genus. Thus, the new genus †Portentosoceros is erected for this fish, which was considered the only known fossil member of the family. Due to the fact that this fish lacks the main synapomorphic characters of the Pentacerotidae, †Portentosoceros gen. nov. is left incertae sedis within the Percoidei, though probably related to Recent armorheads. The observed variability in the number of anal-fin spines (from four to six) in †Portentosoceros sakhalinicus is extremely unusual.

摘要

中新世化石鱼 † Pentaceros sakhaliniсus Gretchina，1975，（Perciformes，Pentacerotidae）根据 20 世纪末在库页岛（西太平洋、俄罗斯远东）收集的正模标本和大量其他材料重新描述。总体外观和身体比例，以及多个（超过三个）臀鳍棘刺的存在，使中新世分类群类似于五角鱼科的成员，而广义的形态特征，例如存在三个神经上突和不存在浅表头骨的粗糙程度使该物种与任何已知的五角节动物属有很大区别。因此，新属 † Portentosoceros是为这条鱼竖立的，它被认为是该家族唯一已知的化石成员。由于这种鱼缺乏 Pentacerotidae 的主要突触特征，† Portentosoceros gen。十一月 在 Percoidei 中留下了 incertae sedis，尽管可能与最近的盔甲有关。在 † Portentosoceros sakhalinicus 中观察到的臀鳍棘数量（从 4 到 6 个）的变异性非常不寻常。