Tur uniscutatus (Turk) 1946 (Acarina:Laelaptidae) from Neotropical Rodents

Abstract

The new genus and species Protonyssus uniscutatus was described by Turk (1946) from a single female specimen taken from the skin of a rodent, Proechimys calidius calidius Thos. captured in Northern Ecuador. Since Protonyssus Turk is a homonym of Protonyssus Trouessart, 1915, Baker and Wharton (1952) replaced it with the name Tur. Recently the authors received collections of parasitic mites through the courtesy of Mr. Eustorgio Mendez and Captain Robert M. Altman. Among them were many mites from Panamanian Proechimys which bore a close resemblance to the description and figure given by Turk for Tur uniscutatus. Since Turk's description was based on a single specimen, mounted in balsam, it seemed possible that the differences noted from our specimens might be more apparent than real. With the cooperation of Dr. Turk the type of Protonyssus uniscutatus was located at the Hope Department of Entomology, University Museum, Oxford, and made available for study through the kindness of M. W. R. de V. Graham. It was found to be identical with the Panamanian material, but due to its dorsal orientation and the type of mounting medium used, certain critical misinterpretations of structure were incorporated in the original description and figure by Turk (1946) causing him to place the genus in the family Macronyssidae. The description states that the digits of the chelicerae are devoid of all traces of teeth, whereas actually the fixed digit has a definite, although small, subterminal tooth. The presternal area of the sternal shield does not actually overlap the sternal plate as originally described, although superficially of that appearance in the type. The very strong, slightly incurved line delimiting the genital shield from the ventral one described by Turk is actually an internal sclerotization; the genital portion of the shield is not demarcated from the ventral portion. The anterior extremity of the genital area is slightly flared and fan-shaped, but is distinctly separated from the metasternal platelets. The genus Tur is considered here as a typical member of the family Laelaptidae with close relationship to the genus Laelaps.