Shin, Jong Hak ¹ ; Chang, Cheon Young ² and Lee, Jimin ³

¹Division of Biodiversity Inventory, Honam National Institute of Biological Resources, Mokpo 58762, Korea & Department of Biological Science, Daegu University, Gyeongsan 38453, Korea.
²Department of Biological Science, Daegu University, Gyeongsan 38453, Korea.
³✉ Ocean Climate Response · Ecosystem Research Department, Korea Institute of Ocean Science and Technology, Busan 49111, Korea.

2026 - Volume: 66 Issue: 3 pages: 714-736

ZooBank LSID: D7B0BC10-64D9-41AF-B991-D5B4F8E123C7

Original research

Keywords

Abstract

Introduction

The genus Agauopsis Viets, 1927 was established to accommodate A. brevipalpus (Trouessart, 1889) (= Agaue brevipalpus Trouessart, 1889) as the type species by Viets (1927). Within the subfamily Halacarinae Viets, 1927, Agauopsis is the most species-rich genus, consisting of 81 valid species assigned to seven species groups with an additional 11 species whose taxonomic placement remains unresolved (Durucan 2025; Shin et al. 2024; WoRMS 2026). Members of the genus are characterized by a broad and flattened idiosoma, a four-segmented palp, a second palpal segment that is generally longer than the combined length of the third and fourth segments, a pair of palps attached laterally to the base of the gnathosoma, a robust medial seta on the third palpal segment, and a rostrum that tapers distally. In addition, the medial and ventral surfaces from the telofemur to tarsus of the first leg bear distinctive spine or spike-like setae (Lohmann 1901; Newell 1947; Viets 1927).

In the northwestern Pacific, 15 species of Agauopsis belonging to five species groups and one ungrouped species have been recorded as follows (Shin et al. 2024): eight species in the brevipalpus group (A. arborea Bartsch, 2003, A. bisetosa Shin, Lee & Chang, 2024, A. dissimilis Bartsch, 2015, A. ivanomorsellii Chatterjee & Chang, 2007, A. longirostris Bartsch, 2015, A. moorea Bartsch, 1992, A. sordida Bartsch, 1992, and A. youngilensis Chatterjee & Chang, 2007); three species in the microrhyncha group (A. humilis Bartsch, 1992, A. robusta Sokolov, 1952, and A. tetrasetosa Shin & Chang, 2019); one species in the furcata group (A. ammodytes Bartsch, 1992); one species in the okinavensis group (A. okinavensis Bartsch, 1986); one species in the ornata group (A. pseudoornata Bartsch, 1985); and one ungrouped species (A. arenaria Bartsch, 1992).

Since Chatterjee and Chang (2007) first recorded A. ivanomorsellii and A. youngilensis in Korea, subsequent studies have added A. tetrasetosa and A. bisetosa, resulting in a total of four species in the documented Korean Agauopsis fauna (Shin and Chang 2019; Shin et al. 2024): A. tetrasetosa in the microrhyncha group and the rest in the brevipalpus group.

Despite these studies, only four species of Agauopsis have been recorded from Korea, representing only about 4% of the currently recognized valid species of Agauopsis. This limited knowledge suggests that the diversity of Agauopsis in Korean waters remains insufficiently explored, particularly in intertidal sandy habitats influenced by groundwater discharge and macroalgal communities. The present study was undertaken to investigate the diversity of Agauopsis inhabiting these poorly studied habitats using detailed morphological observation, including scanning electron micrographs. In addition, identification keys are provided for each species group. By improving the taxonomic knowledge of Agauopsis in Korean waters, this study contributes to a better understanding of the diversity, distribution, and species-group composition of the genus in the northwestern Pacific.

Materials and methods

Halacarid mites were collected from brown algae (Sargassum) and coralline algae (Corallina sp.) attached to intertidal rocky substrates, as well as from sandy sediments influenced by groundwater discharge, at eight coastal sites in Korea (Table 1 and Figure 1).

Macroalgae were placed in containers of tap water for approximately 1 h to induce osmotic shock, and specimens were separated by rinsing the algae through a nylon sieve (mesh size 64 μm). Sandy sediments were collected with a suction device together with surrounding water, immersed in a 7% magnesium chloride (MgCl₂) solution for about 30 min to anesthetize organisms, and then filtered through a nylon sieve of the same mesh size. The separated material was immediately fixed in either 80% ethanol or 5% formalin. Slide preparation and illustration procedures followed Lee et al. (2023). For SEM observation, specimens were immersed in distilled water for more than 24 h to remove fixative, then dehydrated by sequential transfer through a graded ethanol series (10–100%) at 10% increments for 10 min each. After the final ethanol step, specimens were immersed in hexamethyldisilazane, dried completely in a desiccator, coated with platinum using an ion sputter coater (E-1045, Hitachi, Japan), and examined via SEM (S-4300, Hitachi, Japan) at 10 kV. Scale bars in all figures are expressed in micrometers.

Type and voucher specimens are deposited at the National Marine Biodiversity Institute of Korea (MABIK), Seocheon, Korea, and some specimens are deposited at the Marine Interstitial fauna Resources Bank (MInRB) of the Korea Institute of Ocean Science & Technology (KIOST), Busan, Korea.

Terminology and abbreviations in the text and figure captions follow Bartsch (2006): AD, anterior dorsal plate; AE, anterior epimeral plate (AE I and AE II, area representing first and second anterior epimeral plates); ds, dorsal setae on idiosoma (ds-1 to ds-5, first to fifth dorsal setae on idiosoma); GA, genitoanal plate; glp, gland pore(s), numbered glp-1 to glp-4 from anterior to posterior; GO, genital opening; leg I, first leg (leg I to leg IV, first to fourth legs); OC, ocular plate(s); P, palp (P-1 to P-4, first to fourth palpal segments); pas, parambulacral setae; PD, posterior dorsal plate; PE, posterior epimeral plate (PE I and PE II, area representing first and second posterior epimeral plates); pgs, perigenital setae; sgs, subgenital setae.

Systematics

Subclass Acari Leach, 1817

Order Trombidiformes Reuter, 1909

Suborder Prostigmata Kramer, 1877

Superfamily Halacaroidea Cunliffe, 1954

Family Halacaridae Murray, 1877

Subfamily Halacarinae Viets, 1927

Genus Agauopsis Viets, 1927

Agauopsis oligorosetta n. sp.

ZOOBANK: F8962EBB-66DE-4177-AB68-269934443C04

(Figures 2–4)

Type locality — Korea: St. 8, Jeju Island, Seogwipo-si, Haye-dong (33°14′06″N, 126°23′10″E), coarse sand in rock crevices of intertidal rocky shore, 0–1 m depth, 10 Dec. 2023, Chang C.Y., Lee J., and Shin J.H.

Type material — Holotype: ♀ (MABIK CR00261543), mounted in glycerin on Higgins-Shirayama slide (H-S slide), from the type locality. Paratypes: ♂ (allotype, MABIK CR00261544) and 4♀♀, 5♂♂ (MABIK CR00261545 and MInRB-Hl28-S001–S008) mounted in glycerin on H-S slide from the type locality.

Additional material examined — Korea: 3♀♀, 3♂♂, from the type locality, on a stub for SEM; 1♀ (MInRB-Hl28-S012), St. 4, Ulsan-si, Dong-gu, Jujeon-dong, intertidal beach around Durumi Rock (35°33′27″N, 129°27′29″E), coarse sand and fine gravel, 0–1 m depth, 27 Dec. 2023, Lee J.

Etymology — The specific epithet 'oligorosetta' is derived from the Greek oligo- (''few'') and the Latin rosetta (''rosette''), and refers to the presence of only a few rosette pores on AD, AE, and PE, and to their absence on the GA.

Description of female (holotype) — Idiosoma (Figures 2A and 4A) 351 µm long (334–358 µm, mean = 348 µm, n = 6), 239 µm wide (227–242 µm, mean = 236 µm, n = 6), length-to-width ratio about 1.47; all dorsal plates distinctly developed, each separated from one another by membranous cuticle; each plate bearing areolae or costae ornamented with rosette pores, each rosette pore composed of 1 ostium and 6–10 canaliculi.

AD (Figures 2A and 4C) 103 µm long (97–105 µm, mean = 102 µm, n = 6), about 0.29 times as long as idiosoma, 106 µm wide (101–106 µm, mean = 104 µm, n = 6), length-to-width ratio 0.97; divided into anterior and posterior regions at insertion of ds-1; anterior region bearing blunt, dome-like projection, surface ornamented with polygonal foveae, foveae along anterior margin bearing 6–9 rosette pores; posterior region more strongly elevated than anterior region, with anterior and posterior margins truncate while lateral margins rounded; 1 pair of areolae present in posterior region, surface between areolae ornamented with reticulation; each areola with two rosette pore areas, anterior and posterior, each composed of 4–7 rosette pores; 1 pair of glp-1 situated on midway of lateral margin of AD, at anterior 47% of AD.

OC (Figure 2A) 86 µm long (79–93 µm, mean = 88 µm, n = 6), about 0.24 times as long as idiosoma, 40 µm wide (40–45 µm, mean = 43 µm, n = 6), length-to-width ratio 2.15; posteriorly narrowing, pointed apically; central region with raised areola bearing 8–11 rosette pores; glp-2 situated posterolateral to areola, at about midlength of OC; pore canaliculi located posterior to glp-2; absent corneae.

PD (Figures 2A and 4D) 203 µm long (193–207 µm, mean = 204 µm, n = 6), about 0.58 times as long as idiosoma, 174 µm wide (167–179 µm, mean = 174 µm, n = 6), length-to-width ratio 1.17; anterior margin nearly truncate; 1 pair of elongate longitudinal medial costae bearing rosette pores arranged in 2–3 rows; lateral margins with 1 pair of short costae extending from anterior 1/4 to 1/2 of PD, each bearing rosette pores arranged in 1–2 rows; medial costae closely approximated anteriorly but not fused, connected to lateral costae in anterior 1/4 of PD; surface excluding costae ornamented with polygonal foveae, more distinct between medial costae; 2 pairs of gland pores present, glp-3 situated on lateral costae, anteriorly (posterolateral to ds-4), glp-4 located near posterior margin of PD.

Five pairs of ds (Figure 2A): ds-1 situated at anterior 34% of AD; ds-2 located at anterior 17% of OC, anterior to areolae of OC; ds-3 to ds-5 positioned at anterior 7%, 24%, and 52% of PD, respectively, of which ds-4 situated on anterior margin of lateral costae. A pair of adanal setae present dorsobasal to anal cone.

All ventral plates (Figures 2B and 4B) well developed and separated by membranous cuticle, as in dorsal plates; decorated with innumerous circular foveae near ventrolateral margins of AE and PE and posteroventral margin of GA.

AE (Figures 2B and 4E) 126 µm long (118–129 µm, mean = 125 µm, n = 6), 209 µm wide (200–210 µm, mean = 207 µm, n = 6), length-to-width ratio 0.60; posterior margin straight or weakly convex; with 3 pairs of ventral setae; 1 pair of epimeral pores located at anterior 0.61 of AE; with 2 pairs of weakly raised costae, anterior pair lateral to first ventral setae bearing 5–7 rosette pores, posterior pair situated between second and third ventral setae bearing 7–11 rosette pores; lateral margin of AE I and dorsolateral margin of AE II bearing 5–8 and 3–6 rosette pores, respectively.

PE (Figure 2A, B) with 1 dorsal and 3 ventral setae and 2 pairs of weakly raised costae; anterior pair situated anterior to first ventral setae bearing 1–4 rosette pores, posterior pair lateral to second and third ventral setae bearing 6–9 rosette pores; dorsolateral margin of PE I, lateral margin of PE II bearing 3–6 and 5–7 rosette pores, respectively.

GA (Figure 2B) 178 µm long (169–180 µm, mean = 177 µm, n = 6), 0.51 times as long as idiosoma, 146 µm wide (140–149 µm, mean = 146 µm, n = 6), length-to-width ratio 1.22; anterior margin almost truncated; with 3 pairs of pgs located at anterior 52%, 74%, and 86% of GA, respectively, foremost seta situated at level of maximum width of GA and not extending beyond insertion of leg IV, second and last setae located around lateral margins of GO; posteroventral margin of GA and area surrounding GO with circular foveae, without rosette pores. GO 45 µm long (42–46 µm, mean = 45 µm, n = 6), about 0.25 times as long as GA, 34 µm wide (32–34 µm, mean = 33 µm, n = 6), length-to-width ratio 1.32; small, positioned posterior to GA; genital sclerites lacking sgs; distance from anterior margin of GO to that of GA 116 µm, about 2.57 times length of GO.

Gnathosoma (Figure 2A, B) 101 µm long (98–102 µm, mean = 100 µm, n = 6), about 0.29 times as long as idiosoma, 53 µm wide (51–53 µm, mean = 52 µm, n = 6), length-to-width ratio 1.91; lateral and ventral surfaces covered with circular foveae; one ventral side bearing 5–7 rosette pores; rostrum 50 µm long, 0.49 times as long as gnathosoma, anterior end reaching to half of level of P-4; bearing 4 pairs of rostral setae, protorostral and deutorostral pairs of setae situated at tip of rostrum, tritorostral pair at anterior 20% of rostrum ventrally, and last pair (basirostral setae) at posterior 97% of rostrum. Palp (Figure 2A–C) consisting of 4 segments, 8, 34, 6, and 13 µm long, respectively; P-1 without setae; P-2 longest, bearing 1 dorsodistal seta; P-3 bearing 1 dorsomedial spine, 6 µm long, with dentate distal tip; P-4 bearing 3 proximal setae and 3 distal spinules on tip. Tectum (Figure 2A) with anterior margin weakly convex. Chelicera (Figure 2A) nearly as long as gnathosoma; anterior tip reaching anterior margin of rostrum; movable digit terminally bearing 10–12 fine denticles along dorsal margin.

All legs (Figure 3A–D) shorter than idiosoma, leg I largest; legs I–IV 210, 160, 162, and 163 µm long, respectively. Chaetotaxy of legs I–II–III–IV as follows: trochanters 1–1–1–1; basifemora 2–2–2–2; telofemora 5–5–3–3; genua 5–5–3–3; tibiae 8–5–5–5; tarsi (excluding solenidion) 10–6–5–5. Basifemora I–IV bearing 1 filiform ventral seta, dorsal seta filiform on basifemora I and II but bifurcated on basifemora III and IV. All telofemora covered with circular or polygonal foveae on dorsal and lateral surfaces, with weakly developed lamellae ventrolaterally. Telofemur I (Figure 3A, E) with 1 large centroventral and 1 small basiventral bumpy lamella; bearing 3 bifurcated dorsal setae, 1 filiform dorsolateral seta, 1 ventral dentate spine, and 4 smooth spiniform cuticular processes, 2 ventromedial and 2 ventral; proximal ventral process located on anterior margin of centroventral lamella (indicated by arrowheads). Telofemur II (Figure 3B, F) with 1 ventral lamella and 1 small basiventral lamella, ventral lamella extending distally; bearing 3 bifurcated dorsal setae, 1 filiform lateral seta, and 1 filiform ventral seta. Telofemora III and IV (Figure 3C, D) with 1 ventral lamella, 1 bifurcated dorsal seta, 1 filiform lateral seta, and 1 filiform ventral seta. Genu I (Figure 3A, E) with 1 short medial spine bearing denticles at distal tip and 1 short, pointed, naked ventral spine. Tibia I (Figure 3A, E) bearing 4 dorsal setae, 1 ventral seta, 1 long ventral spine, and 2 short medial spines; ventrolateral surface ornamented with polygonal patterns formed by tiny, rounded protrusions. Tibia II (Figure 3B, F) bearing 5 filiform setae; ventrolateral surface weakly ornamented with polygonal patterns, without tiny protrusions. Tibiae III and IV with 5 filiform setae and smooth surfaces, respectively. Tarsus I (Figure 3A, G) bearing 3 dorsal, 2 ventral setae, 1 dentate ventromedial spine, 1 solenidion, and 1 pair of eupathid doublet pas; with 1 pair of smooth lateral claws and 1 bidentate median claw. Tarsus II (Figure 3B, H) bearing 3 dorsal, 1 ventral seta, 1 solenidion, and 1 pair of eupathid singlet pas; tarsi III and IV (Figures 3C, D, I and 4F) similar, bearing 3 dorsal setae, 1 medial eupathid singlet, and 1 lateral spinelet pas, respectively. Tarsi II–IV with 1 pair of lateral claws bearing 11–13 teeth on medial surface of lateral claws; median claw absent on tarsi II–IV.

Male (allotype) — Idiosoma (Figures 2D and 4G) 337 µm long (335–352 µm, mean = 341 µm, n = 6), 220 µm wide (218–232 µm, mean = 223 µm, n = 6). Similar to female, except for genital region. GA (Figures 2E, F and 4H) 174 µm long (171–183 µm, mean = 176 µm, n = 6), 0.51 times as long as idiosoma, 148 µm wide (146–152 µm, mean = 149 µm, n = 6), length-to-width ratio 1.18; anterior margin almost truncated; with 47 (44–49) filiform pgs, additional 1 pair of filiform outlying pgs situated at level of maximum width of GA and anterior 51% of GA. GO 33 µm long (32–34 µm, mean = 33 µm, n = 6), about 0.19 times as long as GA, 23 µm wide (22–24 µm, mean = 23 µm, n = 6), length-to-width ratio 1.43; very small, located posterior of GA; with 3 pairs of sgs situated at anterior 13%, 52%, and 59% of genital sclerites, respectively; distance from anterior margin of GO to that of GA 109 µm, about 3.30 times length of GO.

Remarks — Both the present new species and the subsequently described species, A. polyrosetta n. sp., belong to the pugio group. Comparative morphological differences between the two Korean species and related members of the group are discussed in the ′Remarks' section of the latter species.

Agauopsis oligorosetta n. sp. was collected from a rather unusual habitat. The type locality is located on the southern coast of Jeju Island (Haye-dong), where specimens were obtained from coarse-grained sandy sediments that had accumulated between rocky crevices. This sampling site is largely sheltered from wave action and influenced by groundwater discharge into the coastal zone, resulting in aquatic conditions with very low salinity. Additional material was collected from Jujeon-dong, Ulsan, another locality characterized by a hyporheic zone formed by groundwater inflow into the sea. The freshwater-associated halacarid mite Lobohalacarus weberi (Romijn & Viets, 1924) has previously been reported from this area (Shin et al. 2021). At the type locality of A. oligorosetta n. sp., L. weberi and Soldanellonyx monardi Walter, 1919 (both freshwater-associated halacarid mites previously recorded from Korea) were also observed.

Among the seven valid species currently assigned to the pugio group, A. chelipes Bartsch, 1972 and A. papillata Bartsch, 1972 have been collected from groundwater-related habitats (Bartsch 1972). The two new species described in the present study were also collected from groundwater-influenced sandy substrates.

Agauopsis polyrosetta n. sp.

ZOOBANK: 03776601-9230-4FAB-B890-69965B9284D1

(Figures 5–7)

Type locality — Korea: St. 8, Jeju Island, Seogwipo-si, Haye-dong, rocky shore (33°14′06″N, 126°23′10″E), coarse sand in rock crevices of intertidal zone, 0–1 m depth, 26 May. 2024, Cho K. and Shin J.H.

Type material — Holotype: ♀ (MABIK CR00261546), mounted in glycerin on H-S slide, from the type locality. Paratypes: ♂ (allotype, MABIK CR00261547) mounted in glycerin on H-S slide from the type locality.

Additional material examined — Korea: 1♂ (MABIK CR00261548), same the type locality, 15 Jun. 2023, Jung T.W. and Kim J.G.; 1♂ (MInRB-Hl29-S001), St. 3, Gyeongju-si, Jeonchon Solbat Beach (35°47′22″N, 129°29′36″E), coarse sand and fine gravel, 0–1 m depth, 28 Dec. 2023, Chang C.Y. and Lee J.; 1♀ (MInRB-Hl29-S002), St. 1, Samcheok-si, Gopo Beach (37°08′49″N, 129°21′48″E), coarse sand, 0–1 m depth, 22 Jul. 2024, Lee J., Cho K., and Shin J.H.; 1♂ (MInRB-Hl29-S003), St. 2, Uljin-gun, Osan Beach (36°54′30″N, 129°24′56″E), coarse sand, 0–1 m depth, 24 Jul. 2024, Lee J., Cho K., and Shin J.H.; 1♂ (MInRB-Hl29-S004), St. 6, Jindo-gun, near Gahak pier (34°25′48″N, 126°05′58″E), coarse sand and fine gravel, 0–1 m depth, 20 May. 2025, Cho K., Seo J., and Shin J.H.; 2♂♂, St. 5, Jindo-gun, Sosamdo Islet (34°23′47″N, 126°19′38″E), coarse sand, 0–1 m depth, 20 May. 2025, Cho K., Seo J., and Shin J.H., on a stub for SEM. All additional materials, except those prepared for SEM observation, were mounted in glycerin on H-S slides.

Etymology — The specific epithet'polyrosetta' refers to the abundant rosette pores on the dorsal and ventral plates of idiosoma.

Description of female (holotype) — Idiosoma (Figures 5A and 7A) 360 µm long (354–360 µm, mean = 357 µm, n = 2), 240 µm wide (237–240 µm, mean = 239 µm, n = 2), length-to-width ratio about 1.50; dorsal plates well developed and separated to each other by membranous cuticle; each plate bearing areolae or costae ornamented with rosette pores, each rosette pore composed of 1 ostium and 6–10 canaliculi.

AD (Figures 5A and 7B) 115 µm long (112–115 µm, mean = 114 µm, n = 2), about 0.32 times as long as idiosoma, 117 µm wide (115–117 µm, mean = 116 µm, n = 2), length-to-width ratio 0.98; with rounded protrusion anteriorly, ornamented with polygonal foveae; foveae of anterior margin bearing 6–8 rosette pores; posterior region of AD more strongly elevated than anterior region; anterior and posterior margins nearly straight; a ring-shaped areola, surface with circular foveae; anterior and posterior ridges weakly raised with 1–2 rows of rosette pores; lateral ridges thick, strongly raised with 2–3 rows of rosette pores; remaining surface outside areolae ornamented with reticulation, with scattered canaliculi; 1 pair of glp-1 situated on anterolateral margin of posterior region of AD, at anterior 37% of AD.

OC (Figure 5A) 96 µm long (92–96 µm, mean = 94 µm, n = 2), about 0.26 times as long as idiosoma, 54 µm wide (52–54 µm, mean = 33 µm, n = 2), length-to-width ratio 1.78; lacking corneae; narrowing posteriorly; central region with raised areolae bearing 14–18 rosette pores; glp-2 situated posterolateral to areola, at anterior 52% of OC; pore canaliculi situated posterior to areolae.

PD (Figures 5A and 7C) 196 µm long (193–196 µm, mean = 195 µm, n = 2), about 0.54 times as long as idiosoma, 181 µm wide (177–181 µm, mean = 179 µm, n = 2), length-to-width ratio 1.08; anterior margin straight or weakly concave; 1 pair of robust longitudinal median costae present, costae connected anteriorly, with transverse branches arising from lateral margins of costae at anterior 2/5 of PD and extending to lateral margins of PD; anterior 20% of costae, as well as transverse branches of costae, bearing 1–2 rosette pores, whereas posterior 80% of costae ornamented with 3–5 rows (columns) of rosette pores; 2 pairs of gland pores present, glp-3 situated posterolateral to ds-4, glp-4 at posterolateral edge of costae.

Five pairs of ds (Figure 5A): ds-1 located at anterior 27% of AD; ds-2 at anterior 17% of OC, on anterior edge of areolae in OC; ds-3 to ds-5 situated at anterior 2%, 24%, and 60% of PD, respectively. Anal cone bearing 1 pair of adanal setae dorsally.

Ventral plates (Figure 5B) distinctly separated by membranous cuticle, as in dorsal plates; lateral margins covered with concave areas, with raised areas ornamented with rosette pores.

AE (Figures 5A, B and 7D) 129 µm long (125–129 µm, mean = 127 µm, n = 2), 216 µm wide (211–216 µm, mean = 214 µm, n = 2), length-to-width ratio 0.60; posterior margin slightly concave; with 3 pairs of ventral setae; 1 pair of epimeral pores situated at anterior 0.56 of AE; 2 pairs of raised costae present, anterior costa extending transversely from lateral side of first ventral seta to lateral margin of AE I, posterior costa situated between second and third ventral setae; each costa bearing 1–3 rows of rosette pores; dorsolateral surface of AE II also bearing 5–8 of rosette pores.

PE (Figure 5A, B) with 1 dorsal and 3 ventral setae; 2 pairs of raised costae present; anterior pair circular, each bearing more than 20 rosette pores ventromedially, positioned anterior to first ventral seta; posterior pair situated lateral to second and third ventral setae, rod-shaped, bearing 2–3 rows of rosette pores; additional rosette pores present on dorsolateral surface of PE I (7–10 pores) and on lateral surface of PE II (10–14 pores).

GA (Figure 5B) 192 µm long (188–192 µm, mean = 190 µm, n = 2), about 0.53 times as long as idiosoma, 169 µm wide (166–169 µm, mean = 168 µm, n = 2), length-to-width ratio 1.13; anterior margin slightly convex; 3 pairs of pgs located at anterior 51%, 78%, and 90% of GA, respectively, foremost seta located at level of insertion of leg IV; second and third setae positioned lateral and posterolateral to GO; foveae on lateral surface of GA bearing multiple rosette pores; GO 48 µm long (45–48 µm, mean = 47 µm, n = 2), about 0.25 times as long as GA, 31 µm wide (29–31 µm, mean = 30 µm, n = 2), length-to-width ratio 1.55; sgs absent; distance between anterior margins of GO and GA 129 µm, about 2.69 times GO length.

Gnathosoma (Figure 5A, B) 113 µm long (110–113 µm, mean = 112 µm, n = 2), about 0.31 times as long as idiosoma, 63 µm wide (61–63 µm, mean = 62 µm, n = 2), length-to-width ratio 1.79; dorsal and lateral surfaces ornamented with circular foveae; ventrolateral surfaces bearing 15–18 rosette pores, dorsal plate lacking rosette pores; rostrum 54 µm long, 0.48 times as long as gnathosoma, anterior tip reaching to level of half of P-4; 4 pairs of rostral setae present, protorostral and deutorostral pairs located at distal tip of rostrum, tritorostral pair situated at anterior 18% of rostrum, and basirostral setae positioned at anterior 89% of rostrum. Palp (Figures 5A–C, and 7E) consisting of 4 segments, 9, 38, 6, and 13 µm long, respectively; P-1 lacking setae; P-2 with 1 filiform dorsodistal seta; P-3 bearing 1 small dorsomedial spine, 5 µm long, with dentate distal tip; P-4 with 3 proximal setae and 2 distal spinules on tip. Tectum (Figure 5A) with anterior margin weakly convex medially. Chelicera (Figure 5A) slightly longer than gnathosoma; anterior tip reaching anterior margin of rostrum; movable digit terminally bearing 12–13 fine denticles along dorsal surface.

All legs (Figure 6A–D) shorter than idiosoma, leg I largest; legs I–IV 281, 198, 206, and 206 µm long, respectively. Chaetotaxy of legs I–II–III–IV as follows: trochanters 1–1–1–1; basifemora 2–2–2–2; telofemora 5–6–3–3; genua 5–4–4–4; tibiae 9–6–5–5; tarsi (excluding solenidion) 10–6–5–5. Basifemora I and II each with 1 ventral and 1 dorsal filiform seta; basifemora III and IV bearing 1 filiform ventral and 1 bifurcated dorsal seta, respectively. All telofemora with lamellae extending ventrally from both lateral margins, outer lateral lamellae more strongly developed, surfaces ornamented with polygonal reticulation and numerous small rounded protuberances. Telofemur I (Figure 6A, E) with 3 ventral bumpy lamellae, consisting of 1 spiniform distoventral, 1 large centroventral, and 1 basiventral lamella; centroventral lamella trifurcated; bearing 3 bifurcated dorsal setae, 1 filiform dorsolateral seta, 1 ventral dentate spine, and 2 smooth ventromedial spiniform cuticular processes. Telofemur II (Figure 6B, F) armed with 1 ventral, 1 small basiventral, and 1 ventromedial lamella; ventromedial lamella extending from distal end to proximal one-quarter of telofemur, margin bumpy; bearing 3 bifurcated dorsal setae, 1 filiform lateral seta, and 1 filiform ventral seta. Telofemora III and IV (Figure 6C, D) each with 1 ventral and 1 ventromedial lamella; ventromedial lamella extending from distal end to proximal one-fifth of telofemur; 1 bifurcated dorsal, 1 filiform lateral, and 1 filiform ventral seta. Genu I with 1 medial and 1 small ventral dentate spine. Tibia I (Figure 6A, E) bearing 4 dorsal, 1 lateral, and 1 ventral seta, 1 long ventral spine, and 2 medial spines; tibia II (Figure 6B, F) bearing 5 filiform setae and 1 bifurcated proximal seta; tibiae III and IV (Figure 6C, D) with 5 filiform setae. Tarsus I (Figure 6A, G) with 3 dorsal and 2 ventral setae, 1 dentate ventromedial spine, 1 solenidion, and 1 pair of doublet eupathid pas; tarsus II (Figures 6B, H and 7F) bearing 3 dorsal and 1 ventral seta, 1 solenidion, and 1 pair of singlet eupathid pas; tarsi III and IV (Figure 6C, D, I) each with 3 dorsal setae, 1 medial singlet eupathid pas, and 1 lateral spinelet pas.

Male (allotype) — Idiosoma (Figures 5D and 7G) 373 µm long (352–373 µm, mean = 366 µm, n = 5), 263 µm wide (245–263 µm, mean = 228 µm, n = 5); similar to female, except for genital region. GA (Figures 5E, F and 7H) 200 µm long (192–200 µm, mean = 198 µm, n = 5), 0.53 times as long as idiosoma, 169 µm wide (159–169 µm, mean = 166 µm, n = 5), length-to-width ratio 1.18; anterior margin slightly convex; 53 (50–54) filiform pgs present, 1 additional pair of filiform outlying pgs located at anterior 53% of GA. GO 38 µm long (30–38 µm, mean = 35 µm, n = 5), about 0.19 times as long as GA, 23 µm wide (20–24 µm, mean = 22 µm, n = 5), length-to-width ratio 1.65; 3 pairs of sgs present, situated at anterior 13%, 51%, and 55% of genital sclerites, respectively; distance between anterior margins of GO and GA 125 µm, about 3.29 times GO length.

Remarks — The pugio group includes seven valid species: A. chelipes; A. delicatula Newell, 1971; A. elaborata Bartsch, 1996; A. estuarina Newell, 1984; A. maccaini Newell, 1984; A. papillata; and A. pugio (Trouessart, 1896). The principal diagnostic characters of this species group were treated in detail by Bartsch (1986) under the concept of the ′delicatula group′. Among these characters, the presence of rosette pore areas on both the dorsal and ventral plates, together with a single ventral spine on telofemur I, represents a key combination defining the pugio group (Bartsch 1986).

Agauopsis oligorosetta n. sp. exhibits all diagnostic characters of the pugio group except for one feature. According to Bartsch (1986), members of this group possess spur-like lateral pas together with filiform medial pas on tarsi III and IV, while A. oligorosetta n. sp. bears eupathid pas instead of filiform ones on these tarsi.

Agauopsis oligorosetta n. sp. shows a quite distinguishable character of four smooth, spiniform cuticular processes on telofemur I. Among the seven allied species in the group, A. delicatula, A. estuarina, A. maccaini, and A. papillata have less than four; the remaining three species possess relatively broad costae bearing four rows of rosette pores on the PD, whereas the costae of A. oligorosetta n. sp. are much narrower and bear only one to two rows of rosette pores. In addition, the pores are very sparsely scattered over elevated areas of plates other than the PD in A. oligorosetta n. sp.

Agauopsis oligorosetta n. sp. and A. polyrosetta n. sp. from Korea appear to be closely related to the Australian A. elaborata within the pugio group based on the presence of bifurcated setae on the femora. All three species share a single dorsal bifurcated seta on basifemora III–IV; however, the Korean species differ in having 3–3–1–1 dorsal bifurcated setae on telofemora I–IV, whereas A. elaborata bears such setae only on telofemora I–II (Bartsch 1996). In addition, A. delicatula, described from the Southern Ocean, is the only other species in which some dorsal setae are modified into a bifid form. In the original description, several dorsal setae on telofemora I–IV were noted as bifid, although their exact number was not specified (Newell 1971).

Agauopsis polyrosetta n. sp. most closely resembles A. oligorosetta n. sp. in sharing a similar body size, general morphology of all idiosomal plates and gnathosoma, and the general pattern of leg chaetotaxy. Both new species also bear a pair of eupathid pas on tarsus II, and a medial eupathid and lateral spur-like (spinelet) pas on tarsi III–IV. However, the two species are clearly distinguished by a combination of characters. In A. polyrosetta n. sp., telofemur I has two smooth, ventromedial, spiniform cuticular processes and lacks smooth ventral processes, whereas A. oligorosetta n. sp. has two smooth ventromedial and two smooth, ventral, spiniform cuticular processes on telofemur I. The porose areola of the PD exhibits five rows of rosette pores, compared to two to three rows in A. oligorosetta n. sp. In addition, rosette-pore fields are present in the lateral region of the GA in A. polyrosetta n. sp. but absent in A. oligorosetta n. sp. Finally, genu I bears a dentate spine on both the medial and ventral surfaces in A. polyrosetta n. sp., whereas A. oligorosetta n. sp. has one dentate medial spine and one acute ventral spine.

Key to the species of the Agauopsis pugio group, including two new species from Korea

1. AD with a pointed frontal process
...... 2

—AD with a dome-like protruding structure
...... 3

2. OC with single cornea; telofemur I with one spiniform process on ventral surface
...... A. chelipes

— OC without corneae; telofemur I without spiniform processes
...... A. delicatula

3. Telofemur I with one or two spiniform processes on medial surface
...... 4

— Telofemur I without spiniform lamellae
...... 7

4. Telofemur I with two spiniform processes on ventromedial surface and three bifurcated setae on dorsal surface
...... 5

— Telofemur I with one spiniform process on ventromedial surface and three filiform setae on dorsal surface
...... A. pugio

5. Glp-3 located centrally between ds-3 and ds-4; lateral claws of tarsi II to IV with comb-teeth, but without accessory processes
...... 6

— Glp-3 located slightly posterior to ds-4; lateral claws of tarsi II to IV with comb-teeth and an accessory process
...... A. elaborata

6. Costae of PD each with rosette pores arranged one to three rows wide; GA without rosette pores
...... A. oligorosetta n. sp.

— Costae of PD each with rosette pores arranged three to five rows wide; GA with rosette pores
...... A. polyrosetta n. sp.

7. PD with a pair of costae; P-4 with two basal setae
...... 8

— PD with two pairs of costae; P-4 with three basal setae
...... A. papillata

8. Costae of PD each with rosette pores arranged three to five rows wide; glp-3 located at anterior to ds-4
...... A. estuarina

— Costae of PD each with rosette pores arranged one to three rows wide; glp-3 located at same level as ds-4
...... A. mccaini

Agauopsis robustospina n. sp.

ZOOBANK: 2E460B61-44DD-458F-924D-336646E4E316

(Figures 8–9)

Type locality — Korea: St. 7, Jeju Island, Jeju-si, Gujwa-eup, Pyeongdae-ri, Sehwa breakwater (33°31′47″N, 126°51′16″E), brown and coralline algae on the rock of intertidal zone, 0–1 m depth, 23 Apr. 2006, Chang C.Y. and Lee J.

Type material — Holotype: ♀ (MABIK CR00261549), mounted in glycerin on H-S slide, from the type locality. Paratypes: ♂ (allotype, MABIK CR00261550) and 2♀♀, 1♂ (MABIK CR00261551 and MInRB-Hl30-S001, S002) mounted in glycerin on H-S slide from the type locality.

Etymology — This species epithet ′robustospina′, derived from the Latin robustus (''robust″) and spina (''spine″), refers to the strongly developed, thick and elongate frontal spine on the anterior margin of the idiosoma.

Description of female (holotype) — Idiosoma (Figure 8A) 356 µm long (340–362 µm, mean = 353 µm, n = 3), 246 µm wide (236–248 µm, mean = 243 µm, n = 3), length-to-width ratio about 1.45; all dorsal plated well-developed, separated from each other by membranous cuticle; with 1 long and strong frontal process covered with small papillae.

AD (Figure 8A) 146 µm long (137–148 µm, mean = 144 µm, n = 3), about 0.41 times as long as idiosoma, 125 µm wide (118–126 µm, mean = 123 µm, n = 3), length-to-width ratio about 1.17; frontal process 30 µm long, approximately 0.21 times of AD; polygonal, shallow foveae posterior to frontal process, each fovea ornamented with about 15 canaliculi; 1 pair of irregular costae in medial region extending posteriorly, each costa decorated with 1–2 rows of pores; surface between costae covered with canaliculi; posterior margin convex.

OC (Figure 8A) 92 µm long (87–93 µm, mean = 90 µm, n = 3), about 0.25 times as long as idiosoma, 71 µm wide (69–72 µm, mean = 71 µm, n = 3), length-to-width ratio about 1.29; rhomboid, lateral margin rounded; with an anterolateral protrusion bearing 2 corneae; glp of OC located posterolateral to posterior cornea; surface excluding protrusion covered with small papillae.

PD (Figure 8A) 184 µm long (172–185 µm, mean = 180 µm, n = 3), about 0.50 times as long as idiosoma, 148 µm wide (144–156 µm, mean = 149 µm, n = 3), length-to-width ratio about 1.24; large and rhomboid; anterior margin slightly rounded anteriorly; with 1 pair of longitudinal costae, each bearing a single row of pores, narrowing posteriorly and adjacent; surface between costae covered with canaliculi; 1 pair of glp located at anterior 77% of PD.

Four pairs of ds (Figure 8A): ds-1 located at anterior 41% of AD, 34 µm long; ds-2 on membranous cuticle anterior to OC, as long as ds-1; ds-3 absent; ds-4 situated at anterior 29% of PD and anterolateral to costae, 25 µm long; ds-5 located at anterior 61% of PD and lateral to costae, shortest, 10 µm long. A pair of adanal setae positioned on anal cone near posterior margin of PD, similar in length to ds-4.

All ventral plates (Figure 8B) separated by membranous cuticle, as in dorsal plates; surfaces covered with canaliculi.

AE (Figure 8B) 113 µm long (106–118 µm, mean = 112 µm, n = 3), about 0.32 times as long as idiosoma, 229 µm wide (218–233 µm, mean = 226 µm, n = 3), length-to-width ratio about 0.49; posterior margin weakly convex forward; with 3 pairs of ventral setae; ornamented with pair of garland-shaped areolae composed of polygonal panels; additional polygonal-panel areolae present on between legs I and II of lateral margin, and between 3rd ventral setae; each polygonal panel bearing 7–14 canaliculi.

PE (Figure 8A, B) 135 µm long (126–137 µm, mean = 133 µm, n = 3), about 0.37 times as long as idiosoma; with 1 dorsal and 3 ventral setae; between insertions of legs III and IV decorated with polygonal-panel areolae on ventral surface.

GA (Figure 8B) 158 µm long (150–161 µm, mean = 156 µm, n = 3), about 0.44 times as long as idiosoma, 104 µm wide (99–107 µm, mean = 103 µm, n = 3), length-to-width ratio about 1.52; shield-shaped, anterior margin almost straight or slightly concave medially; ornamented with polygonal-panel areolae from anterolateral margin to anterolateral side of GO; with 3 pairs of pgs located at anterior 36%, 56%, and 73% of GA, respectively; foremost pgs at level of anterior edge of GO, second seta positioned on lateral side of GO, and last pgs situated near posterolateral side of GO. GO (Figure 8B) 69 µm long (65–70 µm, mean = 68 µm, n = 3), about 0.44 times as long as GA; 42 µm wide (40–42 µm, mean = 41 µm, n = 3), length-to-width ratio about 1.64; genital sclerites without sgs. Distance from anterior margin of GO to that of GA 60 µm, about 0.87 times length of GO.

Gnathosoma (Figure 8A, B) 88 µm long (87–91 µm, mean = 89 µm, n = 3), about 0.24 times as long as idiosoma, 50 µm wide (49–51 µm, mean = 50 µm, n = 3), length-to-width ratio 1.76; dorsal and ventral surface covered with punctate pores, except central of ventral surface; rostrum 43 µm long, 0.49 times as long as gnathosoma; with 4 pairs of setae, protorostral setae located at tip of rostrum ventrally, deutorostral setae situated at anterior 12% of rostrum dorsolaterally, tritorostral seta at anterior 26% of rostrum ventrally, basirostral seta at anterior 11% of gnathosomal base; gnathosomal base about 1.04 times as long as rostrum. Palp (Figure 8A–C) consisting of 4 segments, 5, 25, 5, and 11 µm long, respectively; P-1 without setae; P-2 longest, with 1 dorsodistal seta; P-3 with 1 smooth dorsomedial spine (8 µm long); P-4 with 1 long dorsal seta, 1 short ventral seta, and 3 distal spinules; distal tip of palp reaching to anterior end of rostrum or weakly shorter.

Leg I (Figure 9A) 300 µm long, stout, largest of all legs; legs II–IV (Figure 9B–D) 254, 263, and 276 µm long, respectively. Chaetotaxy of legs I–II–III–IV as follows: trochanters 1–1–1–0; basifemora 2–2–2–2; telofemora 8–6–3–4; genua 5–5–3–3; tibiae 8–5–5–5; tarsi (excluding solenidion) 10–5–4–4. Trochanters I and II each with 1 ventromedial seta, 21 and 18 µm long, slightly shorter than inserted segments; trochanter III with 1 ventrolateral seta, 49 µm long, about 1.5 times trochanter III. Telofemur I (Figure 9A, E) with 2 ventral and 1 medial dentate spiniform setae, posterior ventral spiniform seta shorter than anterior one. Genu I with 1 small ventral and 1 medial dentate spiniform setae. Tibia I with 1 ventral and 2 medial dentate spiniform setae; tibia II bearing 1 ventral dentate spine; tibiae III–IV, each with 2 smooth ventral setae. Tarsi I–IV (Figure 9A–D) 45, 51, 51, and 53 µm long and 0.74, 1.17, 1.14, and 1.18 times longer than attached tibia, respectively; tarsus I (Figure 9A, E) with 3 dorsal, 1 blunted ventral, 1 ventromedial, 1 medial dentate spiniform seta, 1 solenidion, and 1 pair of doublet eupathid pas; tarsus II (Figure 9B, F) with 3 dorsal, 1 ventral seta, 1 solenidion, and 1 pair of singlet eupathid pas; tarsi III and IV (Figure 9C, D) with 3 dorsal setae and 1 ventromedial eupathid pas, respectively. All tarsi bearing 1 pair of lateral claws without accessory processes; those of tarsi I and IV with smooth surface; those of tarsi II and III with 10–12 ventral comb-teeth. Median claw present only on tarsus I, bidentate.

Male (allotype) — Idiosoma (Figure 8D) 331 µm long (331–344 µm, mean = 337 µm, n = 2), 225 µm wide (225–232 µm, mean = 228 µm, n = 2). Similar to female except for genital region. GA (Figure 8E, F) 150 µm long (150–158 µm, mean = 154 µm, n = 2), 0.42 times as long as idiosoma, 104 µm wide (104–109 µm, mean = 107 µm, n = 2), length-to-width ratio 1.44; shield-shaped, anterior margin almost straight; ornamented with polygonal-panel areolae anterolateral margin and around to GO; with 30 pgs, consisting of 23 branched and 7 smooth setae; 1 pair of outlying pgs at level of insertion of leg IV and at anterior 38% of GA. GO (Figure 8E, F) 38 µm long (38–40 µm, mean = 39 µm, n = 2), about 0.25 times as long as GA; 27 µm wide (27–30 µm, mean = 28 µm, n = 2), length-to-width ratio about 1.41; with 5 pairs of sgs on genital sclerite, 2 pairs at anterior region and 3 pairs at central region; distance from anterior margin of GO to that of GA, 73 µm long, about 1.92 times length of GO. Spermatopositor (Figure 8E) anterior end extending beyond outlying pgs.

Remarks — Agauopsis robustospina n. sp. is assigned to the ornata group based on the presence of garland-like areolae composed of polygonal panels on the AE (Bartsch 1986, 1999, 2007; Chatterjee et al. 2009). This group currently consists of 13 species, including A. robustospina n. sp. The new species is clearly distinguished from other members of this group by the following diagnostic characters: (1) the frontal process is long and robust, occupying approximately 21% of the length of the AD; (2) the rostrum is shorter than the gnathosomal base; (3) telofemur I bears three spiniform setae; (4) telofemora II and IV has six and four setae, respectively; (5) tibia II bears a single spiniform seta; and (6) tibiae III and IV each have two smooth ventral setae.

Within this species group, A. robustospina n. sp. shows close morphological affinities with four species in sharing a single dentate spiniform seta on tibia II: A. pseudoornata from Mactan Island, the Philippines (Bartsch 1985), A. calidictyota Bartsch, 2007 from Nine Mile Beach, Australia (Bartsch 2007), A. zanzibari Chatterjee, Pešić, Chan & De Troch, 2009 from Zanzibar, Tanzania (Chatterjee et al. 2009), and A. chatterjeei Durucan, 2025 from Bilem Beach, Antalya, Türkiye (Durucan 2025). However, A. calidictyota and A. chatterjeei are distinguished by the anterior tip of the palp extending beyond the distal end of the rostrum and by the presence of two dentate ventral setae on tibiae III and IV, whereas in the other species, including A. robustospina n. sp., the anterior tip of the palp does not extend beyond the distal end of the rostrum, and tibiae III and IV bear two smooth ventral setae. Agauopsis zanzibari is characterized by the presence of an accessory process on the lateral claws of tarsi II–IV and by comb-teeth on the ventral surface of the lateral claws of tarsus IV; however, A. pseudoornata and A. robustospina n. sp. lack the accessory processes on all lateral claws and do not possess comb-teeth on the lateral claws of tarsus IV. Agauopsis robustospina n. sp. is most similar to A. pseudoornata but they are clearly distinguished. In the new species, the pgs surrounding the GO in males consist of both branched and smooth setae (versus exclusively of branched setae in A. pseudoornata); all telofemora lack lamellae (versus well developed in A. pseudoornata); and telofemora II and IV bear six and four setae, respectively (versus five and three setae, respectively, in A. pseudoornata).

The specific name refers to the distinctly elongated frontal process of A. robustospina n. sp., which is the longest among members of the ornata group. The frontal spine is triangular in shape and reaches approximately 21% of the length of the AD. Although detailed descriptions of the frontal process are lacking for most species in this group, comparative evaluation was possible based on the original descriptions and illustrations. In A. inflata Newell, 1984, the only species with a reported frontal process length, it reaches about 18% of the AD length and terminates in a blunt, rounded tip (Newell 1984), distinguishing it from the new species. Furthermore, in A. nonornata Bartsch, 1999, A. ornata (Lohmann, 1893), and A. ornatella Bartsch, 1996, the frontal process is rounded and bears a small, pointed tip medially on the anterior margin (Bartsch 1996, 1999), a condition that clearly differs from the elongated, triangular frontal process of the new species. Agauopsis decorata Otto, 1999 possesses a well-developed, triangular frontal process similar in shape to that of the new species; however, it reaches only about 15% of the AD length (Otto 1999, Figure 6A). In the remaining six species, the frontal process is short and does not exceed 15% of the AD length.

Key to the species of the Agauopsis ornata group, including a new species from Korea

1. Telofemur I with three spines
...... 2

— Telofemur I with four spines
...... A. bacescui

2. Rostrum shorter than gnathosomal base; genu I with one medial and one ventral spine
...... 3

— Rostrum longer than gnathosomal base; genu I with one medial spine and one ventral filiform seta
...... A. inflata

3. Tibia II with one ventral spine
...... 4

— Tibia II with one ventral and one medial spine
...... 8

4. Tibiae III and IV each with two stout and dentate setae, ventrally
...... 5

— Tibiae III and IV each with two slender and smooth setae, ventrally
...... 6

5. Posterior end of OC extends nearly to insertion of leg III; tibia I with three setae
...... A. calidictyota

— Posterior end of OC extends to level midway between insertions of legs III and IV; tibia I with four setae
...... A. chatterjeei

6. Lateral claws of tarsus IV with smooth surface
...... 7

— Lateral claws of tarsus IV each with an accessory process and several comb-teeth
...... A. zanzibari

7. Telofemora II and IV with five and three setae
...... A. pseudoornata

— Telofemora II and IV with six and four setae
...... A. robustospina n. sp.

8. All telofemora with lamellae; lateral claws of tarsi II−IV each with an accessory process
...... 9

— All telofemora without lamellae; lateral claws of tarsi II−IV without accessory processes
...... A. bermudensis

9. Anterior region of AD (between frontal process and ds-1) with a pair of short ridges
...... 10

— Anterior region of AD with a single porose cluster
...... 11

10. P-2 with a cover of fine filaments; P-3 with a denticulate spine
...... A. fenneri

— P-2 without filaments; P-3 with a denticulate spine
...... A. ornatella

11. Tibiae III and IV with two slender and smooth ventral spines, respectively
...... 12

— Tibiae III and IV with two pectinate ventral spines
...... A. nonornata

12. Tip of palp extends to level of distal end of rostrum
...... A. decorata

— Tip of palp extends beyond distal end of rostrum
...... A. ornata

Conflict of interest

No potential conflict of interest relevant to this article was reported.

Acknowledgements

This work was supported by the management of Marine and Fishery Bio-resources Center (2026) funded by the National Marine Biodiversity Institute of Korea (MABIK) and by the research program of the Korea Institute of Ocean Science & Technology (Contract No. PEA0402).

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21. WRMS Editorial Board. 2026. World Register of Marine Species: Agauopsis Viets, 1927 [Internet]. [21 Dece 2004]. Belgium: VLIZ (Flanders Marine Institute) [28 Febr 2026]. Available from: https://www.marinespecies.org/aphia.php?p=taxdetails&id=114768

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