Theriadania, Khaustov & Whitaker, 2019

Khaustov, Alexander A. & Whitaker, John O. Jr., 2019, Two new genera and two new species of the mite family Neopygmephoridae (Acari: Heterostigmata) associated with small mammals from USA, Acarologia 59 (3), pp. 308-322 : 312-316

Genus Theriadania gen. nov

Zoobank: 6D0CFA60-B3B1-42F6-8134-DC013C856FF1

Type species: Theriadania venusta sp. nov.

Diagnosis — Female. Body oval. Gnathosomal capsule distinctly elongate, its length almost two times longer than width, dorsally with one pair of cheliceral setae cha (); setae chb absent, postpalpal setae not evident; palps prominent, with two pairs of setae dFe (, dGe), tiny distal seta-like structure and small tibial claw distally. Subcapitulum with one pair of setae m

and large round alveolar pits n; palps ventrally with accessory setigenous structure (ass), palpal solenidion not evident. Pharyngeal pumps tripartite, pharyngeal pump 1 very small, vestigial separated from pumps 2 and 3. Prodorsum and tergite C separated by soft cuticle. Prodorsum with two pairs of setae (v 2, sc 2), pair of clavate trichobothria sc (1) and elongate 2-chambered stigmata located dorsolaterally and partly covered by lateral projections of prodorsal shield ( Figs 7C , 11A ). Dorsal hysterosomal setae modified, flat, wide and strongly barbed. Tergite C with two pairs of setae (c 1, c 2), setae c 1 located near anterior margin of tergite; tergite D with one pair of setae (d) and pair of elongate, rhombic cupules ia ( Fig. 11B ); tergite EF with two pairs of setae (e, f); tergite H with two pairs of setae h (1, h 2) and pair of inverse drop-shaped cupules ih. Coxal fields I with two pairs of setae (1 a, 1 b); coxal fields II with two pairs of setae (2 a, 2 b); coxal fields III with three pairs of setae (3 a, 3 b, 3 c); coxal fields IV with three pairs of setae (4 a, 4 b, 4 c). Pseudanal segment with three pairs of setae ps (1-3). Ap1 and ap2

well developed and joined with appr, apsej well developed and joined with appr; ap3 weak, diffuse, ap4 long, reaching beyond bases of setae b. 3 Ap5 short, located near the bases of trochanters IV. Secondary transverse apodeme absent. Coxal fields I separated from coxal fields II by u-shaped line. Posterior margin of posterior sternal plate entire, slightly convex in middle part. Anterior genital sclerite (ags) small, bell-shaped, posterior genital sclerite (pgs) small, triangular. Median genital sclerite absent. Ventral idiosomal setae thick and flat. Legs

I distinctly shorter than legs II. Tibiotarsus I cylindrical, with simple hooked claw situated on short pretarsus; seta d of femur I wide and flat, fan-shaped ( Fig. 11C ), seta k short, lanceolate, eupathidium-like. Solenidion ω 2 absent. Claws on tarsi II and III simple, hooked. Claws on pretarsus IV simple, slightly curved. Femora III–IV divided into basi- and telofemur. Setae d

of tibia, pl”, tc’, and (pv) of tarsus of leg II, and pv’ of tarsus III modified, thickened and usually with “crown” of hooked barbs. Empodia on tarsi II and III tongue-shaped; empodium on tarsus IV very long and narrow. An unpaired simple seta u () located near the base of pretarsal claw. Leg setation: leg I; Tr 1 v’ (), Fe 3 (d, l’, v”), Ge 4 (l’, l”, v’, v”), TiTa 17(3) (d, l’, l”, v’, v”, k,

tc’, tc”, p”, ft’, ft”, pv’, pv”, pl’, pl”, s, u, ω 1, φ 1, φ 2); leg II: Tr 1 (v’), fe 3 (d, l’, v”), Ge 3 (l’,

l”, v’), Ti 4(1) (d, l’, v’, v”, φ), Ta 6(1) (tc’, tc”, pl”, pv’, pv”, u’, ω); leg III: Tr 1 (v’), Fe 2 (d,

v’), Ge 2 (l’, v’), Ti 4(1) (d, l’, v’, v”, φ), Ta 6 (tc’, tc”, pl”, pv’, pv”, u’); leg IV: Tr 1 (v’), F 2

(d, v’), Ge 1 (v’), Ti 4(1) (d, l’, v’, v”, φ), Ta 6 (tc’, tc”, pl”, u’, pv’, pv”).

Differential diagnosis — The new genus is most similar to Crossdania gen. nov. by the presence of modified setae on leg II and very long empodium on tarsus IV. The new genus differs from Crossdania gen. nov. by the presence of claws on tarsus IV (vs absent in Crossdania ), by the fan-shaped seta d of femur I (vs. hook-like in Crossdania ), by the absence of solenidion ω 2 (vs. present in Crossdania ), and by unusual elongate 2-chambered stigmata (vs. round, 1-chambered in Crossdania ).

Species included — The genus Theriadania includes only one species Theriadania venusta sp. nov.

Distribution and habitats — Theriadania venusta sp. nov. was collected on Merriam’s

kangaroo rat, Dipodomys merriami ( Rodentia : Heteromyidae ) in USA.

Etymology — The generic name is a combination of two words: Ancient Greek θηρΊΟΝ (theria) meaning, wild beast and dania, the common ending of many Neopygmephorid genera and refers to association of mites with small mammals.

Figures

Figure 7 Theriadania venusta sp. nov., female: A – gnathosoma in dorsal view, B – gnathosoma

Figure 11 DIC micrographs (Hitachi KP-HD20A) ofTheriadania venusta sp. nov., female: A – prodorsum, B – part of tergite D, C – right