Agauopsis bisetosa, ShinK & LeeK & ChangK, 2024

ShinK, Jong Hak, LeeK, Jimin & ChangK, Cheon Young, 2024, A new species of Agauopsis (Acari, Halacaridae) from South Korea belonging to A. brevipalpus group, Acarologia 64 (1), pp. 244-255 : 245-251

publication ID	https://doi.org/ 10.24349/kvkq-s29q
publication LSID	lsid:zoobank.org:pub:81D43216-92C9-46BB-A72D-62922135F518
persistent identifier	https://treatment.plazi.org/id/03F48785-FF98-FFE0-FE32-F9D0E9FFF8D5
treatment provided by	Felipe
scientific name	Agauopsis bisetosa
status	sp. nov.

Treatment

Agauopsis bisetosa n. sp.

Zoobank: 9E2A5B99-D7E7-4AF0-8D93-B5FB2E1ADA42

( Figures 1 View Figure 1 –4)

Type locality — Korea: Jeollanam-do, Yeosu-si, Sindeok-dong, Sindeok beach (34°49′05ʺN, 127°46′01ʺE), mussels ( Mytilus sp. ) attached to rocks, 0−0.5 m depth, 19 Aug. 2018, Shin J.H.

Type material — Holotype: ♀ (HNIBRIV11667), mounted in glycerin on H-S slide, from the type locality. Paratypes: ♂ (allotype, HNIBRIV11668) and 5♀♀, 4♂♂ (HNIBRIV11669– 11677) mounted in glycerin on H-S slide from the type locality.

Additional material examined — 5♀♀, 5♂♂ on a stub for SEM, same data as for holotype.

Etymology — The specific name, bisetosa , refers to ‘two’ ventral ‘setae’ on the posterior epimeral plate, the unique feature of the new species.

Description of female (holotype) — Idiosoma ( Figures 1A View Figure 1 and 3A) 453 µm long (449–521 µm, mean = 471 µm, n = 6), 320 µm wide (317–401 µm, mean = 346 µm, n = 6), length to

width ratio about 1.42; with a small frontal process; all dorsal plates well-developed, separated from each other by membranous cuticle, and covered with small pores (canaliculi) on surfaces excluding areolae and costae.

AD ( Figure 1A View Figure 1 ) 149 µm long (144–164 µm, mean = 155 µm, n = 6), about 0.33 times as

long as idiosoma, 160 µm wide (152–175 µm, mean = 165 µm, n = 6), length to width ratio 0.93; triangular-shaped, rounded posterolaterally, and concave medially at posterior margin; ‘H’-shaped areola protuberant (Figure 3C), decorated with 2−3 polygonal porose panels wide; each porose panels with 6−12 canaliculi (Figure 3D); anterior part of transverse ridge of ‘H’-shaped areola much shorter than rear part; pair of glp-1 located at anteromedial end of anterior arms of ‘H’-shaped areola.

OC ( Figure 1A View Figure 1 ) 61 µm long (59–68 µm, mean = 64 µm, n = 6), about 0.13 times as long

as idiosoma, 116 µm wide (112–125 µm, mean = 120 µm, n = 6), length to width ratio 0.53; narrowing posteriorly and pointed distally; posterior end extending near insertion of leg III; each with 2 corneae on raised transverse areola laterally; areola covered with 9−11 polygonal porose panels; glp-2 and pore canaliculi located at posterolateral to posterior cornea.

PD ( Figures 1A View Figure 1 and 3E) 238 µm long (236–257 µm, mean = 247 µm, n = 6), about 0.53

times as long as idiosoma, 218 µm wide (211–227 µm, mean = 221 µm, n = 6), length to width

ratio 1.09; anterior margin almost truncate; narrowest at anterior 18% of PD, approximately

0.52 times as wide as PD ; with 2 pairs of longitudinal costae, medial costae more distinct than lateral ones; medial costae gradually close to each other towards posterior margin, and each costa with 2−3 polygonal porose panels wide; each lateral costa narrow, with 1−2 polygonal porose panels wide; porose panels on costae consisting of 7−14 canaliculi; remaining area of

PD covered with canaliculi (Figure 3F).

Dorsal setae ( Figure 1A View Figure 1 ): ds-1 situated at anterior 38% of AD; ds-2 on membranous cuticle anterior to OC; ds-3 on membranous cuticle among AD, OC, and PD ; 3 pairs of dorsal setae (ds-4, ds-5, and ds-6) at anterior 22%, 55%, and 100% of PD, respectively, of which anterior two (ds-4 and ds-5) situated at lateral edge of raised medial costae, ds-6 at posterior margin of PD.

All ventral plates ( Figures 1B View Figure 1 and 3B) well-developed and separated by membranous cuticle, and just as dorsal plates covered with small pores.

AE ( Figure 1B View Figure 1 ) 191 µm long (188–216 µm, mean = 204 µm, n = 6), 298 µm wide (291–341

µm, mean = 322 µm, n = 6), length to width ratio 0.64; posterior margin straight or weakly convex; with 3 pairs of ventral setae; a pair of epimeral pores present near trochanter II; 2 pairs

of lyrifissures (= pore canaliculi) located consecutively posterior to epimeral pores.

PE ( Figure 1A, B View Figure 1 ) with 3 pairs of setae, consisting of 1 dorsal and 2 ventral setae; both ventral setae located at the level of insertion of leg III, each ventrolaterally and ventromedially (the latter indicated by an arrowhead); ventral seta lacking in coxal field at the level of insertion of leg IV.

GA ( Figure 1B View Figure 1 ) 171 µm long (164–185 µm, mean = 177 µm, n = 6), 0.86 times as long as

AE, 207 µm wide (201–218 µm, mean = 212 µm, n = 6), length to width ratio 0.83; anterior margin almost straight or slightly convex; distance from anterior margin of GO to that of GA, 40 µm, about 0.45 times length of GO; with 3 pairs of pgs located at anterior 23%, 53% and

67% of GA, respectively, foremost seta at the level similar to anterior end of GO, second pgs at the level of half of GO, and last seta at posterolateral margin of GO, both second and last setae close to GO; sgs absent. GO 89 µm long, about 0.52 times as long as GA.

Gnathosoma ( Figure 2A View Figure 2 ) 131 µm long (128–138 µm, mean = 135 µm, n = 6), about

0.29 times as long as idiosoma, 76 µm wide (74–80 µm, mean = 78 µm, n = 6), length to

width ratio 1.72; dorsal and ventral surface covered with punctate pores; with 4 pairs of setae, consisting of 3 pairs of setae on rostrum and 1 pair of setae on gnathosomal base; protorostral and deutorostral setae situated at tip of rostrum, tritorostral setae at anterior 20% of rostrum ventrally, and basirostral setae at anterior 15% of gnathosomal base; gnathosomal base about 2.05 times length of rostrum. Rostrum 43 µm long, 0.33 times as long as gnathosoma, its tip slightly reaching beyond end of P-3. Palp ( Figures 2A, B View Figure 2 and 4C) consisting of 4 segments, their lengths 7, 28, 9, and 9 µm, respectively; P-1 without setae; P-2 longest, with 1 dorsodistal seta; P-3 with 1 dentate spine (9 µm long, equal to length of P-3) medially; P-4 with 1 long dorsal and 1 short ventral setae proximally, and 3 spinelets at its distal end. Tectum truncated

at its anterior margin ( Figure 2B View Figure 2 ). Chelicera ( Figure 2B View Figure 2 ) 56 µm long, 11 µm wide, reaching to anterior margin of rostrum.

All legs ( Figure 2C–F View Figure 2 ) shorter than idiosoma, legs I–IV 367, 307, 340, and 345 µm long, respectively, and basifemora to tarsi I–IV with pores on surfaces. Chaetotaxy of all legs as follows: trochanters 1-1-1-0; basifemora 2-2-2-2; telofemora 7-6-3-3; genua 5-5-3-3; tibiae

9-6-5-5; tarsi (excluding pas and solenidion) 6-3-3-3. Trochanters III and IV about 2.23 times longer than trochanters I and II. Telofemur I armed with 1 ventral and 2 ventromedial bidentate spines. Genu I with 1 ventral and 1 ventromedial bidentate spines. Tibia I with 1 ventral and

2 ventromedial bidentate spines; tibia II with 1 ventral and 1 ventromedial bidentate spines; tibiae III–IV, each with 1 ventromedial bidentate spine. Tarsi I–IV 48, 55, 69, and 71 µm long, respectively; tarsus I ( Figure 2C, G View Figure 2 ) with 3 dorsal, 2 ventral setae, 1 ventromedial bidentate spine, 1 tiny solenidion (indicated by arrowhead in Figure 2G View Figure 2 ), and a pair of doublet eupathid pas; tarsus I with a pair of smooth lateral claws, and bidentate median claw; tarsus II ( Figures 2D, H View Figure 2 and 4D) armed with 3 dorsal setae, 1 tiny solenidion, 1 lateral doublet (consisting of

1 eupathid and 1 short spinelet) and 1 medial spinelet pas; tarsi III–IV ( Figure 2E, F View Figure 2 ) with 3 dorsal setae and 1 lateral spinelet pas, respectively; tarsi II–IV, each with a dorsal accessory process and 6–7 teeth on either side of curved area on lateral claw ( Figures 2H View Figure 2 and 4D), and without median claw.

Male (allotype) — Idiosoma ( Figure 1C View Figure 1 ) 508 µm long (492–521 µm, mean = 508 µm, n =

5), 370 µm wide (362–401 µm, mean = 382 µm, n = 5). Similar to female, except for genital region. GA ( Figures 1D View Figure 1 and 4A, B) 197 µm long (188–206 µm, mean = 198 µm, n = 5), 0.98

times as long as AE, 221 µm wide (217–230 µm, mean = 224 µm, n = 5), length to width ratio

0.89; anterior margin concave; armed with 41 pgs, a pair of outlying pgs located at anterior 17% of GA, and 39 pgs arranged in two rows around GO (with a range of 36–42 pgs); with 5 pairs of sgs on genital sclerite, 2 pairs at anterior part and 3 pairs at posterior part, of which fourth sgs (14 µm long) larger than others (8 µm long) ( Figures 1E View Figure 1 and 4B). GO 84 µm long, about 0.43 times as long as GA; distance from anterior margin of GO to that of GA, 55 µm long, about 0.65 times length of GO. Spermatopositor large, its anterior end reaching to the level of insertion of leg III.

Remarks — Considering the classification by Bartsch (2015a), A. bisetosa n. sp. evidently belongs to the A. brevipalpus group with 25 congeners, and is characterized by the following combination of characters: AD with an ‘H’-shaped areola; PE with two ventral setae; P-4 with two basal setae and three apical spinelets; telofemur I with one ventral and two ventromedial dentate spines; and tibia II with one ventral and one ventromedial dentate spines.

In the brevipalpus group, the number of dentate spines serves as a highly valuable feature for easy identification ( Bartsch 2015a). Notably, eight species including the new species, exhibit three dentate spines on telofemur I: A. newelli Krantz, 1973 and A. filirostris Macquitty,

1983 from U.S.A. ; A. reticulatus Newell, 1984 from Chile ; A. luxtoni Bartsch, 1986 and A. novaezelandiae Bartsch, 1986 from New Zealand ; A. ivanomorsellii from Korea ; and A. glabra Bartsch, 2009 from Australia ( Bartsch 1986b, 2009 ; Chatterjee and Chang 2007 ; Krantz 1973 ; Macquitty 1983 ; Newell 1984). Among them, A. bisetosa n. sp. is closely allied with A. ivanomorsellii and A. luxtoni in sharing a short frontal process, the presence of an ‘H’-shaped areola on the AD, and two pairs of costae on the PD. However, the new species is distinguishable from them by the following characteristics ( Table 1): (1) ds-4 is located on the PD in the new species and A. ivanomorsellii , whereas it is positioned on the membranous cuticle at the front

of the PD in A. luxtoni ; (2) PE has two ventral setae in the new species, while three ventral

setae are present in A. ivanomorsellii and A. luxtoni ; (3) the length ratio of rostrum/gnathosoma

is 33% in the new species, whereas it is 45% and 40% in A. ivanomorsellii and A. luxtoni , respectively; (4) P-4 possesses three apical spinelets in the new species, while two spinelets

the two