The anatomy of the adult uropodid Fuscouropoda agitans (Arachnida; Acari), with comparative observations on other Acari

Abstract

A thin, compressible, lateral suture and ventral plate overlap permit limited movement of the thick and rigid dorsal and ventral plates of Fuscouropoda agitans. Seven pairs of large dermal glands debouch onto the surface. Trochanteral rotation permits defensive leg adpresion and an insectan type of ambulation. The complex hypopharynx-pedipalpal-coxae has a buccal and cheliceral cavity separated by an atriculated epipharynx. The pharynx is Y-shaped in cross section. Extensive paired salivary glands lie above the very long and dexterous 3-segmented chelicerae, and a large pair of coxal glands debouch on coxae 1. From four blunt-ended tracheae, bundles of unbranching tracheoles extend in specific tracts to all organs. The ventriculus is small with three pairs of large caeca; a tightly packed single layer of digestive cells individually enlarged to absorb-phagocytize and digest the food. A typical mesostigmatid excretory tube is present. A typical acarine synganglion is present; mixed nerves have a basal swelling. A postulated neurosecretory organ arises from the pedipalpal nerve. The oocytes enlarge within funicular stalks from the walls of the small median ovary. A large spermatophore is stored in the seminal vesicle; fertilization occurs during oviposition. A tension hinge partially opens both male and female genital plates; closure effected by muscles acting on very long genital plate apodemes. Within sequentially produced spermatogonial cysts of the testes, meiosis is completely synchronous. A large, multilobed male accessory gland produces a large volume of seminal fluid; a mixture of at least four secretions. The origins and insertions of the body wall, genital organ, digestive tract, mouthpart and leg muscles are listed and illustrated. A comparison of anactinotrichid and actinotrichid mites indicates fundamental and consistent morphological differences in aspects of the cuticle, leg articulations, digestive system, excretory system, reproductive system and coxal glands.Based on external morphology it has been suggested that the Order Acari, the mites and ticks, constitute a diphyletic grouping of Actinotrichida a n d Anactinotrichida (Zachvatkin, '52; Hammen, '72). The Suborders Prostigmata, Acaridida, and Oribatida belong to the Actinotrichida; and the Mesostigmata and METHODS AND MATERIALSA viable culture of Fuscouropoda agitans (Banks, '08) permitted selection of specimens by age or sex and the observation of internal and external parts in mounted, living specimens. Culture tubes made of snap-cap vials with an internal base of plaster-of-Paris: charcoal were kept in desiccators at 95% relative humidity. A small square of 200 mesh, stainless steel screen welded over a circular hole in the cap provided aeration without loss of specimens (Rockett and Woodring, '72). Though related uropodids are probably at least in part predaceous on other mites (Radinovsky, '65; Rohde, ' 591, F. agitans was maintained solely on ground grain and the fungus that grew thereon. Entire specimens and dissected parts we...

Identification of glandular and poroidal idionotal systems inMacrocheles perglaber F. & P. (Acari: Macrochelidae)

“…secretory structures in M. perglaber suggests that it may have potential for use in comparative studies of gland systems of the Gamasida as a whole. It has been illustrated by Athias-Henriot (1969a, b, 1971, 1975a, and further demonstrated by Woodring and Galbraith (1976), that there is considerable variation in the cuticular organotaxy of gamasids. While the dorsal adenotaxy of adult M. perglaber may be characteristic of adults of the genus Macrocheles or of a wider range of genera in the family Macrochelidae, it is likely that an expansion of this study to include adult and immature stases of a variety of neo-and orthotactic (sensu Athias-Henriot, 1971) gamasid taxa would reveal significant differences in dorsal gland number and location, and would provide useful data for an elaboration of systematic relationships between and among these groups.…”

“…In another paper, Athias-Henriot (t975b) associated the dorsal pore and gland systems of amblyseiine Phytoseiidae with muscle attachment fields and setal insertions, delineating a number of"organogerous areas". Woodring and Galbraith (1976) identified six or seven pairs of dorsomarginal dermal glands in the uropodid mite UroobovelIa agitans (Banks) which were thought to secrete what appeared to be an oil. A series of dorsal pore fields, each consisting of a cuticular opening and its most closely associated seta, were illustrated by Evans and Till (1979) in their description of a generalized gamasid mite, Each opening was identified by a signature consisting of the prefix ,p", followed by the setal designation derived from the system of Lindquist and Evans (1965).…”

Types of haemocytes in saprophagous soil mites (Acari: Oribatida, Acaridida), and the correlation between their presence and certain processes within mites

“…For arachnids, including mites and ticks, several types of free cells have been reported in the body cavity (Opilionida: Romer & Gnatzy, 1981;Ixodida: Brinton & Burgdorfer, 1971;Balashov, 1979;Gamasida: Jakeman, 1961;Woodring & Galbraith, 1976;Acaridida: Kanungo, 1969;Woodring & Carter, 1974). The function of these free cells in Opilionida was discussed by Romer & Gnatzy (1981).…”

Fine structure and functional morphology of the mouthparts of a maleVeigaia sp. (Gamasida: Veigaiidae) with remarks on the spermatodactyl and related sensory structures

“…2a,6j,8a,d,9) are known in other predatory gamasids (Gorirossi, 1955a-c;Gorirossi-Bourdeau, 1956;Young, 1968a;Woodring and Galbraith, 1976;Nuzzaci et al, 1996). It is likely that they connect to salivary glands involved in partial digestion of the prey, even though the styli were not traced down to their proximal origins in our study.…”