A new argasid (Argasidae) tick is herein described based on morphology and molecular data obtained from larvae parasitizing Octodon degus and from ticks collected inside burrows in northern Chile. Unfed laboratory-reared larvae were mounted in slides for morphometrical and morphological analyses. Larvae of Ornithodoros octodontus n. sp. share morphological traits with Ornithodoros quilinensis and Ornithodoros xerophylus, two species associated with rodents in the Argentinean Chaco. However, a longer hypostome with two rows of 21 and 22 denticles each one, and conspicuous leaf-shaped anal plates separate O. octodontus. While nymphal stages of O. octodontus lack cheeks and possess a micromammillated dorsal integument, adults have cheeks and exhibit markedly irregular mammillae along their dorsal surface. Phylogenetic analyses of neotropical Argasidae based on mitochondrial 16S rDNA sequences point that O. octodontus forms a monophyletic group with O. xerophylus and an unidentified Ornithodoros sp. from Bolivia, all of them associated with burrow-dweller rodents. Ornithodoros aragaoi and Ornithodoros davisi, two rare species collected once only in the Peruvian Andean Plateau during 1955 are morphologically closely related with adults and nymphs of O. octodontus. Biological observations of O. octodontus revealed autogenic females. For the moment, subgeneric classification of this new species depends on further biological studies. The fauna of ticks occurring in Chile is now represented by 22 species, 11 belonging to the Argasidae family.

本文基于从寄生八齿八齿鼠的幼虫和从智利北部洞穴内收集的蜱获得的形态和分子数据描述了一种新的蜱虫（Argasidae）蜱。将未喂食的实验室饲养的幼虫安装在载玻片上进行形态测量和形态学分析。 Ornithodoros octodontus n. 的幼虫sp。与Ornithodoros quilinensis和Ornithodoros xerophylus具有相同的形态特征，这两个物种与阿根廷查科的啮齿动物有关。然而， O. octodontus具有较长的下口，两排各有 21 和 22 个小齿，以及明显的叶形肛板。虽然O. octodontus的若虫阶段缺乏脸颊并具有微乳头状的背外皮，但成虫具有脸颊并沿其背表面表现出明显不规则的乳头。基于线粒体 16S rDNA 序列的新热带 Argasidae 系统发育分析表明， O. octodontus与O. xerophylus和一种未鉴定的Ornithodoros sp 形成单系群。来自玻利维亚，所有这些都与穴居啮齿动物有关。 Ornithodoros aragaoi和Ornithodoros davisi是1955年仅在秘鲁安第斯高原采集到的两种稀有物种，在形态上与O. octodontus的成虫和若虫密切相关。 O. octodontus的生物学观察揭示了自生雌性。目前，这个新物种的亚属分类取决于进一步的生物学研究。智利的蜱动物群目前有 22 种，其中 11 种属于蜱科。