Alycidae, G.Canestrini & Fanzago, 1877

Uusitalo, Matti, Ueckermann, Edward A. & Theron, Pieter D., 2020, A review of the family Alycidae (Acari, Acariformes) from South Africa, Zootaxa 4858 (3), pp. 301-340 : 303

Family Alycidae G. Canestrini & Fanzago, 1877

The most convenient way to recognize members of the endeostigmatic Alycidae is the presence of two pairs of prodorsal sensilla (ve and sci) inserted in separate bothridia (=large pores). The two pairs of sensilla of Proterorhagiidae (two species in North America) are also well seen in separate bothridia, but this family also has unusually enlarged, rhagidiid-like chelicera. In Nanorchestidae , the first pair of sensilla ve is tiny, rarely seen and in intimate contact with the seta sce forming a mutual sensory organ.

One important character is also the presence of solenidia on femora I. No other endeostigmatids (and very few other mites) have that character ( Bolton et al. 2017). Members of Lordalycidae with neotrichous legs have that character but they have the anterior pair of sensilla ve in a communal depression.

Tendency to add setae on the opisthosoma is also quite common in all genera of Alycidae , although holotrichous species exist in all continents, genera and in the following key.

Alycid mites have ornate cuticular patterns, particulary the Bimichaeliinae . In the Bimichaeliinae , the most obvious, or primary pattern, is comprised of many enlarged outgrowths, termed lamellae, in clumps or on ridges, which may be arranged in a reticulate, or rosette pattern. These lamellae are much larger in Bimichaeliinae than the Alycinae . Within this primary pattern, there is a finer pattern of tiny lamellae, granulae or fragmented ridges, termed the secondary pattern. Both forms of patterning are diagnostic within Bimichaeliinae .

The subfamily Bimichaeliinae is recognized by its reticulate/rosetted primary pattern, although this pattern is sometimes not strongly reticulate but clumped ( Figs. 133 A–D). Within this subfamily, the genus Bimichaelia ( Figs. 133E, F ; Uusitalo 2010: figs. 101, 105) has a secondary pattern of granulae, while Laminamichaelia has tiny ridges furnished with tiny lamellae ( Figs. 133 A–D; Uusitalo 2010: figs. 121, 125). The new tribe described herein has another form. In this case, the large lamellae are still on stellate ridges, but also form small clumps within the rosettes; the secondary pattern is weak and formed by fragmented ridges that lack lamellae ( Figs. 92 , 134A, B ).

In contrast, the Alycinae has no distinctive secondary patterning – instead, their cuticle comprises of a striate pattern of ridges furnished with many small lamellae. Thus, the cuticular patterning in Alycinae is not described as having primary or secondary patterns ( Figs. 134 C–F). However, under a scanning electron microscope, fine secondary patterning can be seen ( Uusitalo 2010: figs. 10, 27, 38, 54, 62, 73, 84, 142), but it lacks lamellae and is fragmented.

In the illustrations herein, the ridges of the primary pattern are not often shown, and the secondary pattern is not often illustrated. This is because the ridges and secondary pattern are not easily seen under phase-contrast microscopy. The drawings of this work focus mainly on the specific character states of the South African fauna and the references to the figures of the revision ( Uusitalo 2010, electronic link in References) are made to clarify and define the other clades.

Figures

FIGURE 133. Primary and secondary patterns of cuticle in the tribe Bimichaeliini (Bimichaeliinae). A, B—stellate primary pattern by large lamellae, secondary pattern by small lamellae, setae prominent in Laminamichaelia sp. of arbusculosa-group, C, D—primary pattern by clumps of large lamellae connected by small lamellae, setae prominent in Laminamichaelia sp. of subnuda-group, E, F—primary pattern by roundish cells of large lamellae, secondary pattern by small granulae, setae inconspicuous in Bimichaelia sp. Abbreviations: Ch—chelicera, P—palp, Gen—genitalia, C, D, E, F, H, PS—segments of opisthosoma.

FIGURE 134. Primary pattern of cuticle in the subfamilies Alycinae and Bimichaeliinae.A, B—primary pattern by clumps and rosettes of large lamellae, secondary pattern absent in Proteromichaelia sp. (Bimichaeliinae: Proteromichaeliini), C, D—striate integument with small lamellae in Amphialycus sp., E, F—striate integument with small lamellae in Petralycus sp. (Alycinae: Petralycini).

FIGURES 90−100. Proteromichaelia sila sp. nov. 90—Prodorsum, naso button-like, distance between counterparts of setae vi larger than between sensilla ve, setae in with some additional setae; 91—Dorsal habitus, neotrichy; 92—Dorsal integument; 93—Ventral habitus, 9–10 genital setae per valve, 4–6 anal setae per valve (cf. Fig. 97); 94—Chelicera, ciliated cheliceral seta; 95—Subcapitulum; 96—Palp tarsus; 97—Genital valve of female, 9 genital setae, 2 pairs of eugenital setae; 98—Tarsus I (2B = 2 baculiform solenidia), famulus I (arrow), Tibia I (1B2C = 1 baculiform solenidion and 2 ceratiform solenidia); 99—Tarsus II (2B), Tibia II (1B2C), Genu II (1B2C); 100—2 slightly bent claws and a setulated empodium.