Crossdania, 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 : 309-310

Genus Crossdania gen. nov.

Zoobank: BC02375D-4CFF-4338-8DE7-12E55D2D3203

Type species: Crossdania tubulosa sp. nov.

Diagnosis — Female. Body oval. Gnathosomal capsule slightly elongate, its length

slightly longer than width, dorsally with two pairs of cheliceral setae cha (, chb); postpalpal

setae not evident; palps prominent, with two pairs of dorsolateral setae dFe (, dGe), tiny distal

seta-like structure and distinct tibial claw distally. Subcapitulum with one pair of setae m;

palps ventrally with accessory setigenous structure (ass) and small solenidion sol (). Pharyngeal

pumps tripartite, connected to each other. 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 small, round

stigmata located just anteriorly to setae v 2. Dorsal hysterosomal setae not modified, except

wide and flat v 2. Tergite C with two pairs of setae c (1, c 2); tergite D with one pair of setae d ()

and pair of round cupules ia; tergite EF with two pairs of setae e (, f); tergite H with two pairs

of setae (h 1, h 2) and pair of round cupules ih. A pair of tube-like sclerotized structures located

under tergite H ( Fig. 5C ). Coxal fields I with two pairs of setae a (, 1 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). Apodemes

1 (ap1) and apodemes 2 (ap2) well developed and joined with prosternal apodeme (appr),

sejugal apodeme (apsej) well developed and joined with appr; apodemes 3 (ap3) weak, diffuse,

apodemes 4 (ap4) long, reaching beyond bases of setae b. 3 Apodemes 5 (ap5) short, located

near the bases of trochanters IV. Secondary transverse apodeme absent. Coxal fields I separated

from coxal fields II by slightly curved and almost connected medially lines. Posterior margin

of posterior sternal plate entire, slightly convex in middle part. Anterior genital sclerite (ags)

small, cup-shaped, posterior genital sclerite (pgs) small, triangular. Median genital sclerite

absent. Ventral idiosomal setae not modified. Legs I slightly shorter than legs II. Tibiotarsus I

cylindrical, with slightly thickened claw situated on short pretarsus; seta d of femur I hook-like,

seta k short, blunt-ended, eupathidium-like. Claws on tarsi II and III thickened basally (padded).

Claws on pretarsus IV absent. Femora III–IV divided into basi- and telofemur. Setae l” of

genu, d of tibia, pl”, tc’, and (pv) of tarsus of leg II, pl”, (pv) of tarsus III and u’ of tarsus IV

modified, thickened and usually with “crown” of hooked barbs ( Fig. 5F ). Empodia on tarsi II

and III distinctly elongate; empodium on tarsus IV very long and narrow. An unpaired slightly

thickened seta-like structure (modified unguinal 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(4) (d, l’, l”, v’, v”, k,

tc’, tc”, p”, ft’, ft”, pv’, pv”, pl’, pl”, s, u, ω 1, ω 2, 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 Protobakerdania Khaustov

and Minor, 2018 by the absence of a median genital sclerite, hook-like setae d of femur I,

the same leg setation, and entire posterior margin of the posterior sternal plate. The new

genus differs from Protobakerdania by the long and narrow empodia on tarsi II and III and

very long empodium on tarsus IV (vs not elongate, flipper-like in Protobakerdania ), by the characteristically modified setae l” of genu, d of tibia, pl”, tc”, and (pv) of tarsus of leg II

(vs. not modified in Protobakerdania ). From all known genera of Neopygmephoridae the new genus differs by the presence of sclerotized tube-like structures under tergite H (vs absent in all other genera) and by the absence of claws on tarsus IV (vs present in all other genera).

Species included — The genus Crossdania includes only one species, Crossdania tubulosa

sp. nov.

Distribution and habitats — Crossdania tubulosa sp. nov. was collected on the Northern grasshopper mouse, Onychomys leucogaster ( Rodentia : Cricetidae ) and Great Basin pocket mouse, Perognathus parvus ( Rodentia : Heteromyidae ) in USA.

Etymology — The generic name is a combination of two words: Cross, the family

name of late American acarologist Earl Cross, and dania, the common ending of many Neopygmephorid genera. The new genus is named after Earl Cross for his contributions in the study of heterostigmatic mites.

Figures

Figure 5 DIC micrographs (AxioCam 506 color) ofCrossdania tubulosasp. nov., female: A – prodorsum, B – tergites D and EF, C – tube-like structures (arrowed) under tergite H, D – prosoma in ventral view, E – posterior sternal plate, F – leg II in dorsal view.