Anomalohalacarus biformis Abé, 1996

Shin, Jong Hak, Chang, Cheon Young & lee, Jimin, 2024, Two psammobiont species of Anomalohalacarus (Acari, Halacaridae) from South Korea, Biodiversity Data Journal 12, pp. e 135719-e 135719 : e135719-

Anomalohalacarus biformis Abé, 1996

Anomalohalacarus biformis Abé 1996 a: 8 , figs. 1–4.

Materials

Type status: Other material. Occurrence: individualCount: 1; sex: female; lifeStage: adult; preparations: mounted in glycerine on H-S slide; occurrenceID: 11FB49B6-4A93-5B4A-AC25-CBF05899B385; Taxon: scientificName: Anomalohalacarus biformis ; kingdom: Animalia; phylum: Arthropoda; class: Arachnida; order: Trombidiformes ; family: Halacaridae ; genus: Anomalohalacarus ; specificEpithet: biformis ; scientificNameAuthorship: Abé, 1996; Location: higherGeography: Northwest Pacific Ocean; continent: East Asia; country: Korea (the Republic of); countryCode: KR; stateProvince: Jeju-do; municipality: Seogwipo-city; locality: Jungmun-saekdal Beach, Saekdal-dong ; verbatimDepth: 0.5–1 m; verbatimCoordinates: 33 ° 14 ' 42 " N 126 ° 24 ' 39 " E; Identification: identifiedBy: Shin, Chang & Lee; dateIdentified: 2024; Event: samplingProtocol: suction; eventDate: 22 / 06 / 2022; Record Level: institutionID: MABIK CR 00257798; institutionCode: Marine Biodiversity Institute of Korea; basisOfRecord: PreservedSpecimen

Type status: Other material. Occurrence: individualCount: 1; sex: female; lifeStage: adult; preparations: mounted in glycerine on H-S slide; occurrenceID: AF088E60-3754-5280-B937-8D2A8154A5FA; Taxon: scientificName: Anomalohalacarus biformis ; kingdom: Animalia; phylum: Arthropoda; class: Arachnida; order: Trombidiformes ; family: Halacaridae ; genus: Anomalohalacarus ; specificEpithet: biformis ; scientificNameAuthorship: Abé, 1996; Location: higherGeography: Northwest Pacific Ocean; continent: East Asia; country: Korea (the Republic of); countryCode: KR; stateProvince: Jeju-do; municipality: Seogwipo-city; locality: Jungmun-saekdal Beach, Saekdal-dong ; verbatimDepth: 0.5–1 m; verbatimCoordinates: 33 ° 14 ' 42 " N 126 ° 24 ' 39 " E; Identification: identifiedBy: Shin, Chang & Lee; dateIdentified: 2024; Event: samplingProtocol: suction; eventDate: 22 / 06 / 2022; Record Level: institutionID: MABIK CR 00257799; institutionCode: Marine Biodiversity Institute of Korea; basisOfRecord: PreservedSpecimen

Type status: Other material. Occurrence: individualCount: 1; sex: male; lifeStage: adult; preparations: mounted in glycerine on H-S slide; occurrenceID: 0D79C7CD-B876-5B77-A698-15C33C0F830C; Taxon: scientificName: Anomalohalacarus biformis ; kingdom: Animalia; phylum: Arthropoda; class: Arachnida; order: Trombidiformes ; family: Halacaridae ; genus: Anomalohalacarus ; specificEpithet: biformis ; scientificNameAuthorship: Abé, 1996; Location: higherGeography: Northwest Pacific Ocean; continent: East Asia; country: Korea (the Republic of); countryCode: KR; stateProvince: Jeju-do; municipality: Seogwipo-city; locality: Jungmun-saekdal Beach, Saekdal-dong ; verbatimDepth: 0.5–1 m; verbatimCoordinates: 33 ° 14 ' 42 " N 126 ° 24 ' 39 " E; Identification: identifiedBy: Shin, Chang & Lee; dateIdentified: 2024; Event: samplingProtocol: suction; eventDate: 22 / 06 / 2022; Record Level: institutionID: MABIK CR 00257800; institutionCode: Marine Biodiversity Institute of Korea; basisOfRecord: PreservedSpecimen

Type status: Other material. Occurrence: individualCount: 1; sex: male; lifeStage: adult; preparations: mounted in glycerine on H-S slide; occurrenceID: 2693CF12-5FB3-52F1-8AF8-582B7C2FCAAE; Taxon: scientificName: Anomalohalacarus biformis ; kingdom: Animalia; phylum: Arthropoda; class: Arachnida; order: Trombidiformes ; family: Halacaridae ; genus: Anomalohalacarus ; specificEpithet: biformis ; scientificNameAuthorship: Abé, 1996; Location: higherGeography: Northwest Pacific Ocean; continent: East Asia; country: Korea (the Republic of); countryCode: KR; stateProvince: Jeju-do; municipality: Seogwipo-city; locality: Jungmun-saekdal Beach, Saekdal-dong ; verbatimDepth: 0.5–1 m; verbatimCoordinates: 33 ° 14 ' 42 " N 126 ° 24 ' 39 " E; Identification: identifiedBy: Shin, Chang & Lee; dateIdentified: 2024; Event: samplingProtocol: suction; eventDate: 22 / 06 / 2022; Record Level: institutionID: MABIK CR 00257801; institutionCode: Marine Biodiversity Institute of Korea; basisOfRecord: PreservedSpecimen

Description

Female

Idiosoma (Fig. 5 A) elongate, 298 µm long (284–298 µm, mean = 291 µm, n = 2), 103 µm wide (98–103 µm, mean = 101 µm, n = 2), length-to-width ratio about 2.89 (2.89–2.90, mean = 2.90, n = 2). AD and PD clearly separated by membranous cuticle with transversely parallel wavy striae. OC absent. Membranous cuticle between AD and PD occupying 59 % of idiosoma; decorated with three pairs of ds (ds- 2 to ds- 4) and 1 pair of glp- 2 situated at anterior 42 % of idiosoma dorsolaterally.

AD (Fig. 5 A and C) 67 µm long (58–67 µm, mean = 63 µm, n = 2), about 0.22 times as long as idiosoma, 36 µm wide (32–36 µm, mean = 40 µm, n = 2), length-to-width ratio 1.86; rectangular in shape with truncated anterior margin and slightly convex posterior margin; ornamented with a longitudinally weakly split areolation in the middle to posterior third of AD, 1 pair of glp- 1 at anterior 21 % of AD laterally, followed by 1 pair of ds- 1.

PD (Fig. 5 A, D) undivided, 43 µm long (39–43 µm, mean = 41 µm, n = 2), about 0.14 times as long as idiosoma, 23 µm wide (21–23 µm, mean = 22 µm, n = 2), length-to-width ratio 1.87; smaller than AD, 0.64 times as long as AD, 0.64 times as wide as AD; convex anterior and lateral margins, and slightly blunt posterior margin; with 2 pairs of glp (glp- 3 and glp- 4) placed at anterior 12 % and 87 % of PD, respectively and 1 pair of ds- 6 at posterior glp- 4.

Five pairs of dorsal setae (Fig. 5 A): ds- 1 positioned at anterior 40 % of AD laterally; 3 pairs of ds (ds- 2 to ds- 4) more and less evenly spaced on membranous cuticle at 20 %, 38 %, and 63 % of idiosoma, respectively; ds- 3 shorter than ds- 2 and ds- 4; ds- 5 absent; ds- 6 shortest, situated at posterior edge of PD.

All ventral plates (Fig. 5 B) small and separated by membranous cuticle with striae, excluding between left and right plates of AE. AE (Fig. 5 B) 69 µm long (58–69 µm, mean = 64 µm, n = 2), about 0.23 times as long as idiosoma, 32 µm wide (26–32 µm, mean = 29 µm, n = 2), length-to-width ratio 2.16; divided into left and right plates by smooth membranous cuticle (Fig. 5 E), of which membranous cuticle with striae extending posterior ventral setae about 1 / 6 posterior part; distance between plates widest, 24 μm near insertion of leg I and narrowing gradually towards posterior part; each plate bearing 2 ventral, 1 lateral setae, and 1 epimeral pore; posterior ventral seta (41 µm long) shorter than others; epimeral pore inserted at border of epimera I and II, about anterior 66 % of AE.

PE (Fig. 5 B) 48 µm long (45–48 µm, mean = 47 µm, n = 2), about 0.16 times as long as idiosoma, 21 µm wide (20–21 µm, mean = 21 µm, n = 2), length-to-width ratio 2.29; situated at anterior 63–81 % of idiosoma; each plate bearing 1 dorsolateral, 2 ventral setae and 1 vestigial scar of seta; ventral setae located at anterolateral corner and at half of PE, respectively.

GP (Fig. 6 A) divided into 3 plates, consisting of 1 pair of anterior and 1 posterior genital plates; anterior genital plates sub-rectangular-shaped, located on either side of genital foramen, 18 µm long (12–18 µm, mean = 15 µm, n = 2), 11 µm wide (8–11 µm, mean = 10 µm, n = 2), length-to-width ratio of 1.64; posterior genital plate inverted triangular posterior to genital foramen, 7 µm long (n = 2), 22 µm wide (20–22 µm, mean = 21 µm, n = 2), length-to-width ratio of 0.32; 3 pairs of pgs, consisting of foremost one located on membranous cuticle anterior to genital foramen and the other 2 pairs on anterior genital plates. Genital foramen (Fig. 6 A) 17 µm long (15–17 µm, mean = 16 µm, n = 2), 3 µm wide (n = 2); slender, pointed at both anterior and posterior tips, widest at anterior 15 % of genital foramen; sgs absent; genital groove placed between posterior genital plate and anal foramen. Ovipositor (Fig. 5 B) tube-shaped, anterior end not reaching anterior edge of PE.

Gnathosoma (Fig. 5 A and B) 118 µm long (114–118 µm, mean = 116 µm, n = 2), about 0.36 times as long as idiosoma, 31 µm wide (29–31 µm, mean = 30 µm, n = 2), length-to-width ratio of 3.81; without ornamentation on surface. Rostrum (Fig. 5 B) 59 µm long, slightly longer than gnathosomal base, its anterior tip not extending beyond distal end of P- 2; 4 pairs of rostral setae, composing of 2 pairs of short proto- and deutorostral setae situated on distal end of rostrum and 2 pairs of long trito- and basirostral setae at anterior 29 % and 59 % of rostrum ventrally, respectively. Palp (Fig. 5 F) 4 - segmented, 11, 58, 9, and 15 µm long, respectively; P- 1 without setae and spines; P- 2 longest, with 1 short proximal and 1 plumose distal setae, dorsally; P- 3 shortest, with 1 dorsomedial spine; P- 4 conical, its terminal end bifurcated, with 3 proximal and 1 tiny distal setae. Chelicera (Fig. 5 A and G) 119 µm long, consisting of basal and movable distal segments; basal segment 107 µm long, with wide proximal part and slender distal part (38 %); movable segment 20 µm long, with about 25 fine denticles dorsally. Tectum (Fig. 5 A) tiny, weakly convex at middle of anterior edge.

All legs (Fig. 6 B – E) slender, leg I longest, 257 µm long, and legs II – IV 174 µm, 175 µm, and 186 µm long (0.67, 0.68, and 0.72 times as long as leg I), respectively. Chaetotaxy for legs I – IV as in Anomalohalacarus angustus sp. nov., except for tibiae 10-6 - 5 - 6 (5); arrangement of legs I – IV similar to the new species. All legs with a pair of lateral claws bearing 1 accessory process dorsally and with single median claw; lateral claws of tarsus I shortest.

Male

Idiosoma (Fig. 5 H), 294 µm long (294–311 µm, mean = 303 µm, n = 2), 102 µm wide (102–110 µm, mean = 106 µm, n = 2), length-to-width ratio about 2.83–2.88; almost similar to female, except for length ratio of AD / PD and genital region. AD (Fig. 5 H and I) 62 µm long (62–76 µm, mean = 69 µm, n = 2), about 0.21 times as long as idiosoma, 35 µm wide (35–42 µm, mean = 39 µm, n = 2), length-to-width ratio 1.77. PD (Fig. 5 H and J) 52 µm long (52–63 µm, mean = 58 µm, n = 2), about 0.18 times as long as idiosoma, 26 µm wide (26–32 µm, mean = 29 µm, n = 2), length-to-width ratio 2.00; undivided, rectangular with truncated anterior and posterior margins; smaller than AD, 0.84 times as long as AD and 0.74 times as wide as AD.

GA (Fig. 6 H) 50 µm long (50–57 µm, mean = 54 µm, n = 2), about 0.17 times as long as idiosoma, 38 µm wide (38–43 µm, mean = 41 µm, n = 2), length-to-width ratio 1.32; elliptical, with a depressed posterior region behind GO and gradually tapering towards posterior ends at both sides; with 7 pairs of filiform pgs, foremost pgs at level of anterior sgs. GO (Fig. 6 H) 20 µm long, (20–26 µm, mean = 23 µm, n = 2), about 0.40 times as long as GA, 12 µm wide (12–17 µm, mean = 15 µm, n = 2); with 2 pairs of sgs, each situated at anterior 26 % and 58 % of genital sclerites, respectively. Spermatocyte (Fig. 6 H) extending beyond anterior end of PE.

Distribution

Japan ( Abé 1996 a), Korea (this study).

Co-occurrence

Anomalohalacarus biformis occurred at a beach on the southern coast of Jeju Island, South Korea. Specimens were obtained by filtering sand with medium-sized grains, along with Actacarus pacificus , Acarochelopodia sp. , Acaromantis sp. , Copidognathus sp. , Maracarus sp., Rhombognathus sp. , Simognathus sp. , and Scaptognathus sp. In addition to halacarids, harpacticoid copepods, nematodes, polychaetes, and ostracods were also present in the sand sediments.

Figures

Figure 5. Anomalohalcarus biformis Abé, 1996. A – G, Female (MABIK CR 00257798). A Idiosoma, dorsal; B Idiosoma, ventral; C AD, dorsal; D PD, dorsal; E AE, ventral; F Palp, lateral; G Tip of chelicerae, lateral. H – J, Male (MABIK CR 00257800). H Idiosoma, dorsal; I AD, dorsal; J PD, dorsal.

Figure 6. Anomalohalcarus biformis Abé, 1996. A – G, Female (MABIK CR 00257798). A GP, ventral; B – E Legs I – IV, ventromedial; F Tip of tarsus I, lateral; G Tip of tarsus II, lateral. H Male (MABIK CR 00257800), left of PE, GP and spermatocyte.