Here you will find general terminology relevant to all mesostigmatid mites as well as family specific terms.
For more broad terminology refer to Dr. Dave Walter’s Glossary of Acarine Terms
Full citations for references can be found in “References“.
General Terminology
anal shield: shield that surrounds the anus. The anal shield will have at least three setae on it (circumanal seta), and may also contain additional ventral setae.
cf. : Latin for confer or compare. Used in naming when there are similarities between species but there is uncertainty as to whether the focal individual is identical to the described species. Ex. Zercon cf. columbianus – Berlese, 1910.
circumanal setae: setae near the anal opening, includes two paranal and one postanal seta.
chelicera: three-segmented pincer-like mouthpart.
dorsal shield: shield that covers all or part of the dorsum of the idiosoma. Mesostigmata can have one shield that covers the entire dorsum (holodorsal shield) two (podonotal and opisthonotal) or three (podonotal, mesonotal and pygidial) shields.
gnathosoma: the “head” of all mites, includes chelicerae and palps.
genital shield: shield that covers the female genital opening, mainly in the cohort Gamasina; can also be called epigynal shield.
idiosoma: everything that is posterior to the gnathosoma, comprises the entire dorsum and leg segments.
lower dorsal shield: shield that covers the posterior portion of the dorsum, also called the opisthonotal shield. The lower dorsal shield can be split into two shields, mesonotal and pygidial shield.
macroseta: a seta that is enlarged relative to the normal state in Mesostimgata, both in length and width.
metapodal shields: a pair of shields (sometimes fused) located above the anal/ventrianal shield near leg IV.
metasternal shields: small shields, located below the sternal shield, that support sternal setae st4 in some taxa. For some families, these shields are absent or fused with the sternal shield.
metasternal-endopodal shield: the fusion of metasternal and endopodal plates. At times, sternal setae st4 will be located on them.
metapodal line: a ridge present in some Uropodina that runs postero-laterally from leg IV.
nodus: small, sclerotized sphere-shaped structure, located in the chelicera of some Uropodina.
nr. : used to name a species when one believes its morphology is similar to another described species, but the focal individual clearly represents a distinctly different species. Ex. Iphidozercon nr. altaicus – Gwiazdowicz and Marchenko, 2012
peritreme: a groove that extends from the stigma along the lateral portion of the mite. Peritremes start ventrally, but can extend to the dorsum of the idiosoma. Peritreme length varies; some extend to setae j1, others are short and do not extend beyond the posterior margin of coxa IV
paranal setae: pair of setae that are located laterally near the anal opening.
perigenital ring: a structure that surrounds the genital shield in females of some Uropodina.
postanal seta: a single seta that is located posterior to the anal opening.
seta (pl. setae): a hair-like sensory structure. Unless otherwise stated, setal notation follows Lindquist & Evans (1965).
seta (barbed): a seta with multiple bristles that come off the main process on both sides of the seta. Barbed setae appear similar to plumose setae but differ in that the individual bristles are difficult to distinguish.
seta (plumose): a seta with multiple filaments projecting off both sides of the main process, giving a feather-like appearance. These filaments vary in length, but are always perpendicular to the main process. Plumose setae can look similar to barbed setae; however, plumose setae have longer projections and individual projections are distinguishable.
seta (serrated): a seta with one side appearing jagged, while the other side appears smooth.
seta (simple): a seta that is smooth on both sides, tapering to a single point.
seta (stout): a seta that is extremely short and fat, almost claw-like in shape. This seta is typically associated with Pachylaelapidae.
seta (spatulate): a seta that is narrow at the base, but more broad at its apex. The shape is similar to that of a common wooden spoon.
spermatheca: a structure in female mites that receives the sperm and sometimes the entire spermatophore. In most Mesostigmata consists of the calyx, atrium and the major duct.
sternal shield: located in the intercoxal area (between the coxa) supporting one to four pairs of seta (st1-4), depending on the genus and family.
sternogenital shield: a shield present in male Mesostigmata. Resides in the intercoxal region (area between the legs, ventrally) and contains the genital opening.
spermatodactyl: structure on the chelicera of male dermanyssine mites (subcohort Dermanyssiae); aids in sperm transfer to the female.
spermatotreme: a slit like structure present on the chelicerae of male Parasitidae; it aids in sperm transfer to females.
stigma: the opening of the respiratory system (tracheal system). The location of the stigma is a defining feature for the orders within Parasitiformes.
tectum: a shelf or ridge that extends anteriorly from the gnathosoma. Appearance varies among genera and families. Other terms include gnathotectum or epistome.
upper dorsal: shield that covers the anterior portion of the idiosoma, also called the podonotal shield.
ventrianal shield: shield that comprises the fused ventral and anal shields. The ventrianal shield contains additional seta beyond the three circumanal setae.
ventral shield: shield (or, more broadly, area) between the genital and anal shields. Ventral shields are common in female Mesostigmata, a good example is in the genus Veigaia.
Terminology Specific to the Zerconidae
Zerconidae
Note: citations are provided for morphology, if terminology of a structure is credited to an author(s).
inner dilation: a small, circular projection out of the peritreme, near the stigma.
posterodorsal cavities:well-developed scars that can be sclerotized, located posteriorly on the opisthonotal shield. Examples can be seen in Zercon.
tectum (Zercon-type): a single, slender anteromedial process, which is divided into two to four tines (Ujvári 2011).
tectum (Parazercon-type): four anterior processes (with the two center processes being the longest) that taper apically (Ujvári 2011).
tectum (Prozercon-type): a single, apically tapering anteromedially process (Ujvári 2011).
peritremal setae: setae located on peritremal shield. Numbers vary from one to three (r1, r2, and r3). Only one genus has a single seta on its shield (r3 seta, Monozercon – Blaszak, 1984), and others have two or three. Typically, the r1 seta is extremely hard to see as it is under leg 1. Due to the location, we were unable to include photos of this seta in the gallery of images on this website.
Mesostigmatid Soil Mites of Alberta 