Venom is a metabolically expensive secretion used sparingly in a variety of ecological contexts, most notably predation and defence. Accordingly, few animals employ their toxins from a distance, and venom-squirting behaviour is only known from select taxa. In scorpions, species belonging to two genera are known to spray venom when threatened, and previous work in Parabuthus transvaalicus shows that venom delivery depends on perceived levels of threat. Here, I describe Tityus (Tityus) achilles sp. nov., a new species of buthid scorpion from Cundinamarca, Colombia. Remarkably, this species is capable of venom spraying, a first for both the genus and the South American continent. Using frame-by-frame video analysis and ballistic equations, I show that T. (Tityus) achilles sp. nov. employs not one, but two types of airborne defences with dramatic differences in reach and venom expenditure. Further, the new species uses an unusually large reserve of prevenom-like secretion for spraying, as opposed to the costly venom used by other spraying scorpions. In light of these key specializations, I propose that toxungen spraying convergently evolved in response to different selection pressures, laying the groundwork for future investigation.

中文翻译：

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南美洲第一只喷洒毒毒蝎子的毒液输送生物力学


毒液是一种代谢昂贵的分泌物，在各种生态环境中很少使用，最明显的是捕食和防御。因此，很少有动物从远处使用它们的毒素，毒液喷出行为只能从选定的分类群中得知。在蝎子中，已知属于两个属的物种在受到威胁时会喷洒毒液，之前在 Parabuthus transvaalicus 中的研究表明，毒液的传递取决于感知到的威胁水平。在这里，我描述了 Tityus （Tityus） achilles sp. nov.，一种来自哥伦比亚 Cundinamarca 的 buthid 蝎子新物种。值得注意的是，该物种能够喷洒毒液，这在该属和南美洲大陆都是第一次。使用逐帧视频分析和弹道方程，我表明 T. （Tityus） achilles sp. nov.使用不是一种，而是两种类型的空中防御，在射程和毒液消耗方面存在巨大差异。此外，新物种使用异常大的类似前蛇血清的分泌物储备进行喷洒，而其他喷洒蝎子使用的昂贵毒液则如此。鉴于这些关键专业，我提出 toxungen 喷洒是响应不同的选择压力而趋同进化的，为未来的研究奠定了基础。