A NEW SPECIES OF CHIGGER MITE AND THE RECORD OF A GASTROINTESTINAL NEMATODE IN SCELOPORUS CAUTUS (SQUAMATA: PHRYNOSOMATIDAE) FROM THE CHIHUAHUAN DESERT PROVINCE IN COAHUILA, MEXICO.

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 (σ1-2) 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.

A New Species of Morelacarus (Acariformes: Prostigmata: Leeuwenhoekiidae) Associated With Sceloporus grammicus (Squamata: Phrynosomatidae) From the Mexican Plateau, Zacatecas, Mexico.

A new species of chigger mites, Morelacarus uazi n. sp., parasitizing lizards of the species Sceloporus grammicus from Mazapil, Zacatecas, Mexico, is described and illustrated. This new taxon differs from other species of the genus by having a palpal claw with 4 subequal paired prongs, and it can be further distinguished by the combination of the following characters: presence of onychotriches and mastitarsala III, absence of mastitibiala III, subterminala I, and parasubterminala I, and the palpal setal formula B/B/BBb. Additionally, an identification key for the species of the genus Morelacarus is presented. The new species represents the seventh species assigned to the genus and the first species described from a Mexican lizard.