Fedrizziidae Trägårdh 1937, Tragardh, 1937

Seeman, Owen D., 2007, Revision of the Fedrizziidae (Acari: Mesostigmata: Fedrizzioidea), Zootaxa 1480, pp. 1-55: 5-8

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http://doi.org/ 10.5281/zenodo.176844

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Fedrizziidae Trägårdh 1937


Fedrizziidae Trägårdh 1937  

Type genus. Fedrizzia Canestrini  

Diagnosis. Sternogynial shield enlarged, the only genital shield visible externally ( Figs 2 View FIGURE 2 b, 3). Latigynial shields internal and strap-like, closely approximating the ventral shield, the lateral sides of the genital opening, and posteriorly connected to a tiny, internal mesogynial shield. Mesogynial shield associated with an internal porose plate. Ventrianal shield present, partially or wholly separate from ‘ventral’ shields (fused exopodal, marginal, metapodal and ventral shield). Seta h 3 of male 5–10 long, positioned closer to midline of gnathosoma   than h 2 ( Fig. 4 View FIGURE 4 ). Corniculi large, broad, semi-membranous flaps that approximate the internal malae ( Figs 1 View FIGURE 1 , 4 View FIGURE 4 ). Marginal dorsal setae small, <15 long, excepting the anterior pair of dorsal setae. Dorsal shield with an anterior hyaline process, sometimes extending posterior of coxa II. Associated with the Passalidae   ; other host records accidental. Known distribution: Australia, Indonesia, Malaysia, Thailand, Papua New Guinea, and Philippines.

Remarks. The Fedrizziidae   and Klinckowstroemiidae   have extremely similar morphologies and host associations, and differ only in the formation of the female genital shields ( Fig. 2 View FIGURE 2 ) and their biogeographical distribution. Here, I have retained the interpretation of the marginal, internal genital elements in Fedrizziidae   representing highly reduced latigynial and mesogynial shields. The latigynial shields are strap-like and lay beneath the edge the sternogynial shield, and meet posteriorly at a small, ovular mesogynial shield. The junction of these shields is associated with an internal porose plate, especially obvious in Neofedrizzia   , and also present in the Klinckowstroemiidae   . However, unlike the Klinckowstroemiidae   , the Fedrizziidae   have up to three processes that lie mostly behind the sternogynial shield, extending up to 100 µm posteriorly. I regard these processes as the modified apodemes and condyles of the genital shields of Klinckowstroemiidae   , especially the sternogynial apodeme ( Rosario & Hunter 1987).

Kethley (1977) defined the Klinckowstroemiidae   + Fedrizziidae   by five setal absences: al 1 and pl 1 on genu I, av 1 and pl 1 on genu II and pl 1 on tibia IV. However, my analysis of leg setation shows these setae are present in Klinckowstroemiidae   and Fedrizziidae   ( Figs 5–8 View FIGURES 5 – 8 ). Kethley (1977) did not have immature life stages for these families, so his absences may represent different interpretations of leg chaetotaxy.

The number of setae on each leg segment is uniform across the family: Cx I –IV 2 - 2 - 2 - 1; Tr I –IV 6 - 5 - 5 - 5; Fe I –IV 12 - 10 - 7-8; Ge I –IV 11 - 11 - 9 - 9; Ti I –IV 13 - 10 - 9 - 9; Ta I –IV 33 (approx.)- 19 - 19-22. Kethley (1977) implied that the chaetotaxy of fedrizziid and klinckowstroemiid mites is identical, but in comparison to Rosario and Hunter (1987) there are several differences: the trochanters are 6 - 4 - 4 - 4, i.e., one less seta on Tr II –IV; the femora are 10 - 9 - 7-8, i.e., two less setae on femur I and one less seta on femur II; and the tibiae are 11 - 10 - 9 - 9, i.e., two less setae on tibia I. Furthermore, Rosario and Hunter (1987) report 17 setae on tarsi II –III (lacking the small terminal setae ad 1 and pd 1) and 18 setae on tarsus IV (lacking ad 1 and pd 1, but also av 4 and pv 4 on the intercalary sclerite). I have examined specimens of Klinckowstroemiella   from Ecuador and Klinckowstroemia   from Mexico and found all of these differences to be incorrect: leg chaetotaxy of Klinckowstroemiidae   is the same as the Fedrizziidae   .

The modified legs of adult fedrizziid mites make the assignment of leg setae difficult, but the legs of immature life stages are unspecialised and leg chaetotaxy of the deutonymph is considerably simpler ( Figs 9– 12 View FIGURES 9 – 12 ). I have applied the deutonymphal setal names for N. camini   to that of the adult ( Figs 5–8 View FIGURES 5 – 8 ), thus making the assumption that the chaetotaxy of N. camini   deutonymphs is applicable to all fedrizziid and klinckowstroemiid mites. I believe this is a reasonable assumption because of the uniformity of leg chaetotaxy across the Fedrizziidae   and Klinckowstroemiidae   . The chaetotaxy of the Fedrizzioidea is also comparable to that of M. vazquezus   : fedrizzioids have two additional setae on femur I, pl 2 and av 3; seta al 3 instead of al 2 (this represents a different interpretation of which al seta is on the basifemur) on femur II; lack seta al 2 on genu II; lack seta pv 1 on genu III; and lack setae pv 1 and pl 1, but has seta pd 3 on genu IV.

Within the Fedrizziidae   , the form of leg setae is moderately useful in Fedrizzia   and less so (but still worthwhile) in Neofedrizzia   . However, I have generally avoided using these characters in diagnoses because setae intermediate between slender and spine-like are difficult to interpret.