Neonyssus triangulus n. sp., Nasal Mite (Acarina: Mesostigmata) from the White-Winged Dove (Aves: Columbiformes) and Key to the Species of the Genus Neonyssus

Abstract

A medium-large mite, with long, flexible setae on legs and on ventral opisthosoma; dorsal posterior plate acutely triangular; anal plate narrowly ovate with the paired anal setae slightly anterior to a line drawn through middle of anal pore; coxae II, III, and IV each with a low, semicircular protuberance on the posterior ventral face. Female (figs. 1 to 6). All measurements are given in microns. Length, excluding gnathosoma, 620; varying from 570 to 660; width, 420. Dorsal side (fig. 6). About two-thirds of the dorsum is covered by two large plates. The podosomal plate is broader than long, with the anterior margin rounded, the posterior margin straight. It measures 210 microns long by 300 wide. The hysterosomal plate is triangular; the anterior margin is straight or slightly biconcave, the sides straight or very slightly sinuate, the posterior tip truncate, rounded, or obtusely pointed. Both plates are lightly reticulated; on the posterior plate the reticulations form fairly large, rather regular polygons, on the anterior plate they form narrow, transverse spaces. Both plates devoid of setae, but the anterior plate has 6 to 7 pairs of small, circular pores (or perhaps they are setal bases) and the posterior plate has three pairs such pores. One pair of short setae is between the two plates, two pairs of setae flank the posterior plate and two more pairs are near the posterior margin of the body. One pair of tiny setae is near the antero-lateral margin of the podosomal plate. There are also 4 to 7 pairs of small pores in the vicinity of the stigma. The stigma and short peritrem'e are dorso-lateral, between legs III and IV. Dorsal body striation are weak. Ventral side (fig. 1). The three sternal setae are very small, only the third pair is clearly discernible. No sternal plate. Epigynial plate longitudinally striated and fairly short and narrow, with the posterior margin rounded, truncate, or bluntly pointed. Genital setae short and weak and each flanked by a small pore; in none of the forty specimens before me, are the genital setae on the plate. Anal plate elongate-oval, thickened laterally, with a well-developed cribrum; the three setae slender and equal, about twice as long as diameter of anal pore. There are two pairs of setae between genital