Gahniacarus gersonus, Beard, Jennifer J. & Ochoa, Ronald, 2011

Beard, Jennifer J. & Ochoa, Ronald, 2011, New flat mite genera (Acari: Trombidiformes: Tenuipalpidae) associated with Australian sedges (Cyperaceae), Zootaxa 2941, pp. 1-37: 14-15

publication ID

http://doi.org/ 10.5281/zenodo.204686

DOI

http://doi.org/10.5281/zenodo.5612526

persistent identifier

http://treatment.plazi.org/id/0A68182D-FF8E-F869-FF39-FC05EC9CF868

treatment provided by

Plazi

scientific name

Gahniacarus gersonus
status

sp. nov.

Gahniacarus gersonus   sp. nov. Beard & Ochoa

( Figs 1 View FIGURE 1 b, 9–11)

Types. Holotype. Ƥ. Australia, New South Wales, Mt Alexander Reserve, Mittagong, 34 ° 27 ’ 26 ”S, 150 ° 27 ’00”E, 24.iv. 2005, ex. red-fruited saw sedge Gahnia sieberiana Kunth.   ( Cyperaceae   ) ( BRI voucher # PIF 30818 View Materials ), J.J. Beard (QM). Paratypes. Same data as holotype: 4 Ƥ (separate slides), 6 Ƥ (same slide), 2 Ƥ (same slide), 1 deutonymph, 1 protonymph (QM); 3 Ƥ, on separate slides ( USNM).

Diagnosis. Adult female ( Figs 1 View FIGURE 1 b, 9). As per genus, in addition to: setae sc 1 inserted on weakly developed tubercles, elongate; setal pair c 1 -c 1 inserted on tubercle; f 2 and f 3 tubercles separated; large tubercles (not bearing setae) present between sc 1 -c 1, posterad c 1. Dorsal opisthosomal setae e 3, f 2, f 3 present.

Immatures ( Figs 10–11 View FIGURE 10 View FIGURE 11 ). Larva not known. Protonymph with posterior opisthosomal setae e 3, f 3, h 1 minute and setae f 2 similar to other dorsal setae. Deutonymph with posterior opisthosomal setae f 3, h 1 minute and setae d 1, e 3, f 2 similar to other dorsal setae.

Remarks. Setae f 2 and f 3 are inserted on well separated tubercles in G. gersonus   , whereas setae f 2 and f 3 are inserted on contiguous tubercles in Gahniacarus tuberculatus   ; prodorsal setae sc 1 are elongate and tapered in G. gersonus   , whereas setae sc 1 are similar in size to other dorsal setae in G. tuberculatus   .

Adult female. (15 measured).

Dorsum. ( Figs 1 View FIGURE 1 b, 9) Body measurements: v 2 –h 1 287 – 315, sc 2 –sc 2 75 – 86, c 3 –c 3 81 – 92, f 3 –f 3 37 – 42. Dorsal cuticle variable, with some indication of a prodorsal shield: oblique plicae mesad setae sc 2 and eyes; transverse plicae posterad prodorsal shield to level of c 3; cuticle between c 1 –e 2 mostly smooth with some oblique grooves and plicae associated with tubercles; longitudinal plicae present between f 3 –f 3. Setae c 1 inserted together on large single central tubercle; setae sc 1, c 3, d 3, e 3, f 2 on large tubercles; single smooth tubercle present posterad c 1. Setae sc 1 obviously elongate, strongly barbed; h 1 minute, barbed; h 2 elongate, smooth with minute distal club; all other dorsal setae thick with dorsal surface strongly barbed, almost pubescent (especially basally) and ventral surface smooth: v 2 37 – 43, sc 1 171 – 215, sc 2 32 – 38, c 1 43 – 58, c 3 31 – 35, d 1 45 – 53, d 3 35 – 41, e 3 33 – 40, f 2 48 – 55, f 3 28 – 38, h 1 3, h 2 150 – 166.

Gnathosoma   . ( Fig. 9 View FIGURE 9 ) Gnathosoma   elongate, as long as leg I. Dorsal cuticle with longitudinal plicae; ventral cuticle finely papillate anterad setae 1 b. Ventral setae m absent. Palps with three segments; 0, 2, 0(2); tibia with two setae (d 13 – 16, v 10 – 13); tarsus with two eupathidia (5 – 6, 7 – 9). Cheliceral stylets 147 – 158.

Venter. Cuticle with fine, mostly transverse, plicae; plicae longitudinal on ventral gnathosoma   to setae 1 a; plicae transverse between 1 a -ag, becoming thicker and more widely spaced laterally between leg II – III (similar to dorsal plicae); plicae on genital flap longitudinal laterally, arching anteriorly around g 1; plicae longitudinal to oblique laterad genito-anal region. Setae g 1 and g 2 on genital flap. All ventral setae fine, smooth. Setal measurements: 1a 63 * – 146, 1 b 64 – 84, 2 b 18 – 30, 2 c 15 – 22, 3 a 20 – 25, 3 b 13 – 21, 4 a 1 49 – 77, 4 a 2 48 – 80, 4 b 10 – 19, ag 18 – 20, g 1 18 – 25, g 2 16 – 24, ps 1 13 – 19, ps 2 10 – 15 (* = broken). Setae 1 a, 1 b, 4 a 1, 4a2 elongate, fine (difficult to consistently determine full length); setae 2 b and 2 c widely separated.

Spermatheca. ( Fig. 9 View FIGURE 9 ) A long narrow tube from the genital opening (anterad seta ps 2) terminates in a small blunt-tipped, narrow, cylindrical vesicle (10 – 11).

Legs. ( Fig. 9 View FIGURE 9 ) Setal formula for legs I – IV: 1 - 1-3 - 0-5 - 7 (1), 2 - 1-3 - 0-5 - 7 (1), 1 - 1-2 - 0-3 - 3, 1 - 1-2 - 0-3 - 3 respectively. Tarsi I and II each with one antiaxial solenidion ω ” (5 – 7, 4 – 5 respectively) and two distal eupathidia p ζ ’- p ζ ” (7 – 8, 6 – 7; 6 – 8, 6 respectively); ta I – IV u’-u” asymmetrically barbed. Femur I with long, barbed dorsal seta (50 – 62). Tenent hairs increasing in length, shortest basally to longest distally.

Colour. This species is lemon green with small black spots internally (presumably food in the gut).

Adult male. Unknown.

Deutonymph. (1 measured).

Dorsum. ( Fig. 10 View FIGURE 10 ) Body measurements: v 2 –h 1 258, sc 2 –sc 2 78, c 3 –c 3 82, f 3 –f 3 43. Cuticle completely plicate, mostly transverse plicae, with some longitudinal plicae on prodorsum between v 2 –sc 1 and posteriorly between setae d 1 –h 1. Setae f 3, h 1 minute; setae h 2 elongate, smooth; all other setae thick, strongly barbed: v 2 23 – 24, sc 1 52, sc 2 27 – 28, c 1 23, c 3 25 – 27, d 1 24, d 3 26 – 29, e 3 20 – 22, f 2 29 – 30, f 3 3, h 1 2, h 2 91.

Gnathosoma   . ( Fig. 10 View FIGURE 10 ) Gnathosoma   elongate, as long as leg I. Ventral setae m absent. Palps with three segments; formula 0, 2, 0(2); tibia with two setae (d 11, v 8); tarsus with two eupathidia (5, 8). Cheliceral stylets 119.

Venter. Cuticle completely plicate; longitudinal plicae on ventral gnathosoma   to setae 1 a, transverse plicae 1 a– g 1; oblique plicae laterad ps 1–2 (anal region); lateral plicae between legs II – III stronger and more widely separated than medial plicae. Setal measurements: 1a 47 * – 92, 1 b 32, 2 b 17 – 18, 2 c 14 – 15, 3 a 16, 3 b 11, 4 a 1 41, 4 b 8, ag 9, g 1 7 – 8, ps 1 6 – 7, ps 2 4 (* = broken). Setae 4 a 2, g 2 absent.

Legs. ( Fig. 10 View FIGURE 10 ) Setal formulae for legs I – IV: 1 - 1-3 - 0-5 - 7 (1), 2 - 1-3 - 0-5 - 7 (1), 1 - 1-2 - 0-3 - 3, 1 - 0-2 - 0-3 - 3 respectively. Tarsis I and II each with one antiaxial solenidion ω ” (4, 3 respectively) and two distal eupathidia p ζ ’-p ζ ” (7, 6; 6, 6 respectively); ta I – IV u’-u” asymmetrically barbed. Femur I with long, barbed dorsal seta (31).

Protonymph. (1 measured).

Dorsum. ( Fig. 11 View FIGURE 11 ) Body measurements: v 2 –h 1 202, sc 2 –sc 2 72, c 3 –c 3 77, f 3 –f 3 31. Cuticle completely plicate, mostly transverse plicae, with some longitudinal plicae on prodorsum between setae v 2 –sc 1 and posteriorly between setae d 1 –h 1. Setae e 3, f 3, h 1 minute; h 2 elongate with minute club; all other setae thick, strongly barbed: v 2 8 – 10, sc 1 29, sc 2 21 – 22, c 1 16, c 3 23 – 24, d 1 12 – 15, d 3 24 – 25, e 3 3 – 5, f 2 18 – 19, f 3 1 – 2, h 1 1 – 2, h 2 74.

Gnathosoma   . ( Fig. 11 View FIGURE 11 ) Gnathosoma   almost as long as leg I. Band of oblique plicae ventro-lateral margins. Ventral setae m absent. Palps with three segments; formula 0, 2, 0(2); tibia with two setae (d 9 – 10, v 7 – 8); tarsus with two eupathidia (5, 7). Cheliceral stylets 93.

Venter. Cuticle completely plicate; plicae longitudinal gnathosoma   to setae 1 a, transverse 1 a–ag, oblique laterad ps 1–2. Setal measurements: 1a 42 – 48, 1 b 36 – 42, 2 c 9, 3a 11, 3 b 5, ag 3, ps 1 3, ps 2 3. Setae 2 b, 4 a 1, 4a2, 4b, g 1, g 2 absent.

Legs. ( Fig. 11 View FIGURE 11 ) Setal formulae for legs I – IV: 1 - 0-3 - 0-5 - 7 (1), 1 - 0-3 - 0-5 - 7 (1), 1 - 0-2 - 0-2 - 3, 0- 0-2 - 0-3 - 3 respectively. Tarsus I and II each with one antiaxial solenidion (3, 2 – 3 respectively) and two distal eupathidia p ζ ’-p ζ ” (5, 5; 5, 4 respectively). Femur I with long, barbed dorsal seta (19).

Larva. Unknown.

Host. Red-fruited saw sedge, Gahnia sieberiana   ( Cyperaceae   ), growing in open eucalypt forest along a watercourse, in clay soil.

Distribution. Mt Alexander Reserve, Mittagong, New South Wales, Australia.

Remarks. Individuals of this species wedge their bodies into the longitudinal grooves on the ventral surface of the leaf blades of the host plant. Once in the grooves, the adult mites extend their elongate anterior (sc 1) and posterior setae (h 2) out over the surface of the leaf blade. Numbers of mites were higher towards the tip of the leaf blades than near the base.

Etymology. This species is named for our colleague and fellow tenuipalpiphile, Uri Gerson.

BRI

Queensland Herbarium

USNM

Smithsonian Institution, National Museum of Natural History