First report of Chorioptes texanus (Acari: Psoroptidae) in Argentina.

In Argentina it has historically been assumed that Chorioptes bovis is the only species involved in clinical cases of bovine chorioptic mange. The aim of this communication is to present the first formal report based on morphometric studies of C. texanus in Argentina. Mange mites were collected through skin scrapings of areas with superficial dermatitis on adult dairy cows from three dairy farms located in Santa Fe, Entre Ríos and Córdoba provinces (Argentina). Clinical lesions were characterized by dermatitis located at the base of the tail and ischiorectal fossa, pruritus with hyperkeratosis and crust formation. The taxonomic determination was based on morphological characters. For species-level identification, adult male specimens were isolated from each sample and measurements were taken by using an image analysis software. Based on characteristics such as body length (243-275 μm), the bases of opisthosomal setae h2 and h3 positioned close to each other, and seta ps2 (65-73 μm) being longer than ps1 (28-30 μm). On tarsus III, the fIII seta was bifurcate. Body length was 1.4 times longer than setae cp. A total of 34 male specimens were identified, all corresponding to C. texanus. The morphometric results of the present study closely align with those documents in the literature and constitute the first diagnoses of C. texanus parasitizing cattle in Argentina.