Philodina haejooni n. sp. Figures 3 and 4 urn:lsid:zoobank.org:act: 52D619D8-E10B-4FA7-9993-08C7B3CD1A5D Holotype and paratypes. On permanent slides, deposited in the collection of the National Institute of Biological Resources, Incheon, Korea (holotype: NIBRIV0000862827; two paratypes: NIBRIV0000862828 and NIBRIV0000862829). Type locality. Hwansangsup gotjawal, Hangyeong-myeon, Jeju-si, Jejuteukbyeoljachi-do, Korea. GPS coordinates based on WGS84 datum 33°19’21.5”N / 126°15’48.0”E. Material. Six specimens sorted out from leaf litter, collected by Min Ok Song and Chang-Ho Lee on 12 August, 2019. Differential diagnosis. This new species is easily distinguished from its congeners by the leaf margin-shaped longitudinal ridges on trunk. The margins of these longitudinal ridges are slightly expanded, lobed, sinuate, and sometimes bluntly pointed. Even though the trunk of Philodina haejooni n. sp. is lightly granulated, the lobed and sinuate parts of the longitudinal ridges are not from the compaction of the granules on trunk, but from the slight expansion of the margins. The genus Philodina has several species/subspecies with highly granulated trunk such as P. corrugata, P. clypeata Song & Lee, 2020, P. rugosa rugosa Bryce, 1903 and its two other subspecies, P. r. coriacea Bryce, 1903 and P. r. callosa Bryce, 1903, P. scabra Milne, 1916, and P. verrucosa Song & Lee, 2020. None of these Philodina species has leaf margin-shaped longitudinal ridges on trunk like those P. haejooni n. sp. has. The other important diagnostic characteristics of this new species include the lateral expansions of cingulum as well as the extended lateral folds on each side of the pseudosegment bearing dorsal antenna in feeding. Description. No eyespots. Body lightly granulated. Rostral lamella bilobed and very short; narrower than rostrum width; with tufts of cilia posterolaterally. Rostrum round and slightly shorter than its width. Corona wider than cingulum; the ratio of corona width to cingulum width about 1.12: 1–1.13: 1. Sulcus as wide as pedicel width. Upper lip arched and bilobed medially; as high as sulcus base; much lower than trochal discs. Cingulum extended laterally; each extension short and round laterally; cingulum slightly wider than cingulum pad; the ratio of cingulum width to cingulum pad width about 1.10: 1–1.11: 1. Antenna short. Two extended lateral folds on either side of pseudosegment bearing antenna in feeding. Teeth 3/3. Pharyngeal tube much shorter than trophi length. Longitudinal ridge on trunk slightly expanded and leaf margin-shaped; margins lobed, sinuate, and sometimes bluntly pointed. Rump gradually tapering to foot; preanal pseudosegment plump posteriorly; anal pseudosegment round medially. Foot very short and with four pseudosegments; the ratio of total body length in creeping to foot length about 8.4: 1. Spurs long, finger-shaped, thin and with wide interspace; slightly plump medially; lateral margins of spurs tapering to dull and knobbed ends; interspace width slightly wider than spur length; the ratio of interspace width to spur length about 1.3: 1. Egg oval and with smooth surface. Measurements. Total length in creeping 180–194 μm. Total length in feeding 130–140 μm. Rostrum length 18 μm. Corona width 40–45 μm. Cingulum width 36–40 μm. Cingulum pad width 32–36 μm. Antenna length 14–18 μm. Greatest neck width in creeping 34–35 μm. Greatest trunk width in creeping 36–44 μm. Greatest trunk width in feeding 45–56 μm. Spur length 6–10 μm. Distribution. This new species is known only from its type locality. Etymology. This new species is named after authors’ son, Hae-Joon Lee.

Published as part of Song, Min Ok & Lee, Chang-Ho, 2022, Descriptions of Philodinavus koreanus n. sp. and two new species of Philodina (Rotifera, Bdelloidea) from Korea, pp. 399-411 in Zootaxa 5129 (3) on pages 404-406, DOI: 10.11646/zootaxa.5129.3.4, http://zenodo.org/record/6501197