Suctobelbella (Flagrosuctobelba) subiasi Bayartogtokh & Bae, 2024, sp. nov.

Suctobelbella (Flagrosuctobelba) subiasi sp. nov. (Figures 1, 2) Diagnosis. Body length 155–176 μm, width of notogaster 94–109 μm. Rostrum narrowly rounded centrally, with two large teeth laterally. Tectopedial field short, but rather wide, irregular oval; median prodorsal tubercle subtriangular. Lamellar and interlamellar setae medium long, thin, smooth. Bothridial setae long, nearly setiform, slightly expanded medially, and pectinated in distal half. Interbothridial tubercle large, subtriangular; postbothridial tubercle rounded. Humeral tubercles relatively small, rounded, medial tubercle larger than lateral tubercle. Notogastral setae setiform, smooth, subequal in length. Apodemes apo.2 and apo.sj strongly developed, without medial cavity; epimeral and anogenital setae medium long, subequal in length, all thin, smooth. Measurements. Body length 155–176 μm, width of notogaster 94–109 μm, length of notogaster 101–113 μm. Integument. Body colour yellowish brown, body surface nearly smooth, anterior part of prodorsum and interbothridial region with few tubercles. Lateral side of prodorsum partially covered by granular cerotegument. Prodorsum (Figs 1A, C, 2A, C). Rostrum rounded centrally, with two large teeth laterally. Tectopedial field (tf) short, but rather wide, irregular oval; median prodorsal tubercle (mt) subtriangular, without posterior projection. Rostral seta (ro) geniculate, ciliate unilaterally in medial part. Lamellar (le) and interlamellar (in) setae medium long, thin, smooth; exobothridial seta not evident. Bothridial seta (bs) long, flagellate, nearly setiform, slightly expanded medially, and pectinated in distal half. Interbothridial tubercle (ibt) large, subtriangular; postbothridial tubercle (pbt) small, rounded. Notogaster (Figs 1A, 2A, C). Almost round, slightly longer than wide, anterior margin straight. Humeral tubercles relatively small, round in shape, medial tubercle (mt) slightly larger than lateral tubercle (lt), opposite to postbothridial and interbothridial tubercles, respectively. Lenticulus (len) semicircular, with poorly developed anterior border. Notogastral setae setiform, smooth, subequal in length; seta la inserted at same level or slightly posterior to lm. Lyrifissure im and opisthonotal gland opening (gla) clearly developed, other lyrifissures not evident. Gnathosoma (Figs 1B, 2B). Subcapitulum, palp and chelicera typical for family (e.g., see Woas 1986; Ermilov & Hugo-Coetzee 2017); subcapitulum longer than wide; subcapitular setae a and m subequal in size; seta h represented by its alveolus. Epimeral region (Figs 1B, 2B). Apodemes apo.2 and apo.sj strongly developed, without medial cavity; posterior margin apo.4 with series of small tubercles. With typical epimeral setal formula 3-1-3-3; epimeral setae medium long, subequal in length, all setiform, smooth. Discidium rounded distally. Anogenital region (Figs 1B, 2B). Six pairs of genital, one pair of aggenital, two pairs of anal and three pairs of adanal setae thin, smooth; genital setae g 2 – g 4 and g 6 slightly shorter than other anogenital setae. Seta ad 1 inserted lateral to anal aperture. Distance ad 3 – ad 3 much shorter than ag–ag. Adanal lyrifissure (iad) located laterally, adjacent and parallel to anal aperture. Legs. Leg setation typical for family (e.g., see Woas 1986; Ermilov & Hugo-Coetzee 2017). Tarsi with smooth claw. Formula of leg setation: I (1-5-2-4-20), II (1-5-2-4-13), III (2-3-1-3-13), IV (1-2-2-3-10); formula of solenidia: I (1-2-2), II (1-1-2), III (1-1-0], IV (0–1–0]. Material examined. Holotype (female) and seven paratypes (four females and three males): Gotjawal Park, Seoguipo-shi, Jeju-do, Korea, soil under broad-leaved trees, 25 July 2023, Coll. Y.S. Bae. Distribution and habitat ecology. Currently, this species is known only from the type locality, Gotjawal, which is a volcanic forest formed on round, lumpy basalt, which makes its appearance wildly different from inland forests. The forest was created when trees, grasses, and flowers settled on land formed by hardening lava that erupted from a parasitic cone. The roots of tall trees are clearly exposed above ground due to lack of topsoil. Etymology. This species is named in memory of our esteemed colleague and friend, late Dr. Luis S. Subías, in recognition of his considerable contribution to the systematics of oribatid mites. Remarks. Among the known species of Suctobelbella (Flagrosuctobelba), the following species, S. (F.) arcuata Hammer, 1977, S. (F.) baloghi (Forsslund, 1958), S. (F.) chabarica Rjabinin, 1975, S. (F.) elegantula (Hammer, 1958), and S. (F.) lata Chinone, 2003 resemble the new species in general appearance (see Forsslund 1958; Hammer 1958, 1977; Ryabinin 1975; Chinone 2003). The first species mentioned above, S. (F.) arcuata, which is known from South Asia (Pakistan) differs from the new species in the presence of five pairs of genital setae (vs. six pairs in new species); conspicuously barbed notogastral setae (vs. smooth in new species); nearly smooth or finely barbed bothridial seta (vs. pectinated in new species); relatively narrow and distally pointed humeral tubercles (vs. rounded in new species); and much larger body size (210 vs. 155–176 μm). The Holarctic species, S. (F.) baloghi studied by Forsslund (1958), Moritz (1971), Mahunka and Mahunka-Papp (2001), and Weigmann (2006) can be distinguished from the present new species in the structure of rostrum, which has 4-6 teeth (vs. with only two teeth in new species); different location of notogastral seta la (la inserted at level anterior to lm vs. la inserted at same level or slightly posterior to lm); and distinctly larger body size (175–200 vs. 155–176 μm). The East Asian species, S. (F.) chabarica studied by Ryabinin (1975), Bayartogtokh and Bae (2024) is distinguishable from the present new species in the rhomboid or subquadrangular interbothridial tubercle (vs. subtriangular in new species); distally pointed postbothridial tubercle (vs. distally rounded in new species); different location of notogastral seta la (la inserted at level anterior to lm vs. la inserted at same level or slightly posterior to lm); and much larger body size (185–206 vs. 155–176 μm). The semicosmopolitan species, S. (F.) elegantula studied by Hammer (1958), Aoki (1961), and Chinone (2003) is different from the new species in having rhomboid or subquadrangular interbothridial tubercle (vs. subtriangular in new species); densely granulated anterior part of prodorsum (vs. smooth in new species); much shorter notogastral setae (vs. medium long in new species); and distinctly larger body size (176–247 vs. 155–176 μm). Another East Asian species, S. (F.) lata studied by Chinone (2003) and Bayartogtokh and Bae (2022) differs from S. (F.) subiasi sp. nov. in the presence of large medial cavity in the epimeral region (vs. absent in new species); relatively short, but thick notogastral setae (vs. relatively long, thin in new species); and far larger body size (192– 208 vs. 155–176 μm).