The chigger species Acomatacarus coahuilensis n. sp. (Acariformes: Trombidiformes: Leeuwenhoekiidae) inhabiting the neck scales of the wary spiny lizard Sceloporus cautus Smith, 1938 (Squamata: Iguania: Phrynosomatidae), from Chihuahuan Desert Province, Coahuila, Mexico, is described herein. The new mite species is assigned to the genus AcomatacarusEwing, 1942, based on a palptarsus with 6 branched setae plus the tarsala (ω). This new species can be separated from the other species in this genus mainly based on the combination of the following characters: presence of mastisetae (MTa) on tarsus III and tibiala (φ) on tibia III, subterminala (ζ₁), parasubterminala (z), and pretarsala (ζ₂) on tarsus I, 2 genualae (σ_1-2) on genu I, onychotriches and claw-like empodium of legs I–III, and absence of mastisetae on tibia III. In addition to the new species, the gastrointestinal nematode Skrjabinoptera phrynosoma (Ortlepp, 1922) Schulz, 1927 (Physalopteridae), was also found, which represents a new host record in the wary spiny lizard. This study reports the third species of the genus Acomatacarus recorded from Mexico and the first record of chigger mites and helminth parasites associated with Sc. cautus.

恙螨种Acomatacarus coahuilensis n. sp。本文描述了栖息于墨西哥科阿韦拉州奇瓦瓦沙漠省的警惕的多刺蜥蜴 Sceloporus cautus Smith, 1938（鳞目：鬣蜥：蜥蜴科）颈鳞上的（螨形目：Trombidiformes：Leeuwenhoekiidae）。1942 年，新的螨种被归入Acomatacarus Ewing属，其基础是具有 6 个分枝刚毛的触须加上跗节 (ω)。这个新种可以与该属的其他种区分开来，主要基于以下特征的组合：跗骨 III 上存在乳腺 (MTa) 和胫骨 III 上存在胫骨 (φ)、subterminala (z 1 ₎、parasubterminala (z ) 和跗骨 I 上有前跗骨 (ζ ₂ )，膝 I 上有 2 个膝部 (σ _1-2 )，腿 I-III 上有甲毛和爪状前足，胫骨 III 上没有乳突。除了新物种外，还发现了胃肠道线虫Skrjabinoptera phrynosoma (Ortlepp, 1922) Schulz, 1927 (Physalopteridae)，它代表了警惕的刺蜥蜴的新宿主记录。这项研究报告了墨西哥记录的第三种Acomatacarus物种，以及与 Sc 相关的恙螨和蠕虫寄生虫的第一个记录。尾根。