The king‐of‐the‐salmon, Trachipterus altivelis (Lampriformes), has an unusual set of oral jaws which allow it the ability to protrude the entire upper jaw, containing the premaxilla and the maxilla bones, to extreme distances. Here, we provide a short description of the cranial anatomy and mechanism of jaw protrusion in T. altivelis using hand‐drawn illustrations (by KF), supplemented by CT‐scans. We then place the protrusion abilities of T. altivelis into context by comparing anatomical jaw protrusion with protrusion from other members of the Lampriformes, other unrelated species with highly protrusile jaws, and unrelated species with more stereotypical amounts of jaw protrusion. Through these comparisons we demonstrate that T. altivelis is indeed, capable of some of the most extreme premaxillary protrusion as of yet discovered, even when taking into account the extreme morphological modifications that facilitate said protrusion. That is to say, T. altivelis can protrude the premaxilla farther than one would predict from the length of the ascending process alone.

中文翻译：

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鲑鱼 Trachipterus altivelis 的上颌前突极度突出

鲑鱼之王 Trachipterus altivelis (Lampriformes) 有一组不同寻常的口腔颌骨，这使它能够将整个上颌（包括前上颌骨和上颌骨）突出到极远的距离。在这里，我们使用手绘插图（由 KF 提供）简要描述了 T. altivelis 颌骨前突的颅骨解剖结构和机制，并辅以 CT 扫描。然后，我们通过比较解剖颌骨前突与 Lampriformes 其他成员的前突、具有高度前突下颌的其他无关物种以及具有更多刻板突出量的无关物种，将 T. altivelis 的前突能力置于上下文中。通过这些比较，我们证明 T. altivelis 确实能够进行一些迄今为止发现的最极端的前上颌前突，即使考虑到促进所述突出的极端形态变化。也就是说，T. altivelis 可以比仅根据上升过程的长度预测的更远地突出前上颌骨。