Prolixus Beard, Fan & Walter, 2005

Beard, Jennifer J. & Seeman, Owen D., 2025, A new flat mite genus and five new species (Tetranychoidea: Tenuipalpidae) from native Australian sedges (Cyperaceae), Zootaxa 5637 (1), pp. 1-56 : 21-22

Prolixus Beard, Fan & Walter, 2005

Type species: Prolixus forsteri Beard, Fan & Walter, 2005: 170 .

Diagnosis (modified from Beard et al. 2005 and Xu & Zhang 2014).

Adult female. Body highly elongate, at least four times longer than wide; prodorsal and opisthonotal shields absent or poorly defined. Palps 3-segmented; palp tarsus with 2 terminal phaneres (both moderately short or both long). Anterior margin of prodorsum smooth, or with small median projection; dorsal opisthosoma with 7, 8 or 9 pairs of setae (c3, d1, d3, e3, f3, h1, h2 present; c1, c2, d2, e2 absent; e1, f2 present or absent). Dorsal setae variable; sc1, sc 2 elongate and usually highly pilose; posterior lateral opisthosomal setae usually elongate and highly pilose; opisthosomal setae d1, d3, e1 usually much shorter; seta h2 flagellate. Ventral and genital shields not developed, both regions membranous and merged together; ventral setae 1c, 2b, 2c, 3b, 4b, ag present or absent; two pairs of ps setae, anal valves membranous, setae ps3 inserted far anterior to ps2; ventral setae g1 inserted well anterior to g2; 4a1–2 usually present, elongate, fine (absent in P. setifolius Xu, Huang & Zhang ); lacking supernumerary coxal setae 3a2. Trochanters variable, 0-0-0-0, 0-0-1-0 (tr III lʹ added in protonymph) or 1-1-0-0 (tr I–II vʹ added in adult stage); femora 4-4-2-2, 4-3-2-2, 3-3-1-1 or 1-1-0-0, femur I–II with d inserted dorsally; genua variable, 2-2-0-0 (d absent), 2-1-0-0, or 1-1-0-0 (d absent, lʹʹ absent on ge II or ge I–II); tibiae 5-5-3-3; tarsi usually 8(1)-8(1)-4-4 or 8(1)- 8(1)-5-5, rarely 7(1)-7(1)-3-3. Tarsi I–II with setae ftʹʹ absent; setae ftʹ finely elongate. Tarsi III–IV with tc′ absent, and tc″ present or absent. Tarsal claws and empodia pad-like. Adult male. As in female, in addition to: lacking solenidion on tarsi III–IV; femora 4-4-2-2 or 2-2-1-1; genua 2-2-0-0 or 1-1-0-0; tarsi 9(2)-9(2)-4-4, 8(2)-8(2)-4-4 or 8(2)-8(2)-3-3.

Remarks. The setation on coxae I–IV is variable in this genus, from the full standard 2-2-1- 1 in P. forsteri to the greatly reduced 1-0-0-0 in P. setifolia . On coxa II, seta 2c is added in the protonymph, prior to seta 2b being added in the deutonymph. When there is only one seta present on coxa II, its name will depend on the stage in which it is added during ontogeny. Likewise with the setae added to trochanters I–IV. When there is just one seta present on trochanter III, its name will depend on the stage in which it was added, with l′ being added in the protonymph and v′ added in the deutonymph or adult. For example, P. meyerae has 0-0-1-0 on trochanters, with the seta being added to trochanter III in the protonymph making it l′; while P. nicholasi has 1-1-1-0 on the trochanters, where l′ is added to trochanter III in the protonymph and v′ is added to trochanters I–II in the deutonymph. Males of P. insignis sp. nov. also have 1-1-1-0 present on the trochanters, however, these are all added in the deutonymph and are considered to be v′.

As in several other tenuipalpid genera (e.g. Raoiella ( Beard et al. 2018) , Obuloidini ( Beard et al. 2022), Prolixus exhibits sexual dimorphism during ontogeny (in addition to the standard additional solenidion on the tarsi of males), as discussed further by Xu et al. (2017). Here, P. insignis sp. nov. males and females of all stages can be separated by dorsal opisthosomal seta f2 being present on the males and absent on the females. Additional sexual dimorphic character states appear in the deutonymph stage with the male having both 2b and 2c present on coxa II and v′ on trochanters I–III, while the female has only 2c present on coxa II, and the trochanters are nude. See also Remarks for P. insignis sp. nov.