Philodina nitida nitida Milne, 1916

Song, Min Ok & Lee, Chang-Ho, 2023, Four bdelloid rotifers new to Korea, Journal of Species Research 12 (2), pp. 115-121 : 119-120

4. Philodina nitida nitida Milne, 1916 ḒNjṵṞệ (ṳḑ)

Philodina nitida Milne, 1916, pp. 67 - 68 , pl. 5, figs. 9 - 9a.

Material examined. Three specimens from mosses at

Banjeong, Daegwallyeong, Hoenggye-ri, Daegwalnyeongmyeon, Pyeongchang-gun, Gangwon-do, 37°41′44.7″N, 128°45′49.6″E, on 4 Oct. 2021.

Diagnosis. Rostrum much narrower than head in creeping. Upper lip arched, bilobed medially, and lower than trochal discs. Corona much wider than cingulum. Sulcus as wide as pedicel width. Cingulum pad slightly expanded anterolaterally. Two small eye spots. Pharyngeal tube slightly shorter than trophi length. Teeth 3 + 1/1 + 3. Last trunk pseudosegment round squarish posteriorly. Anal pseudosegment much narrower than a half of the greatest trunk width in creeping. Foot with four pseudosegments. Spurs long, thin and divergent; interspace slightly wider than spur base width.

Measurements. Total length in creeping 202 μm. Total length in feeding 167 μm. Greatest trunk width in creeping 52 μm. Corona width 43 - 44 μm. Cingulum width 35 μm. Cingulum pad width 36 - 38 μm. Spur length 8 μm.

Remarks. Milne described this subspecies-level taxon, Philodina nitida nitida , with a variety, P. n. var. decens ( Milne, 1916) . The major difference between P. n. nitida and P. n. decens is in the morphology of feeding head. The ratio of corona width to cingulum width is 1.25: 1 in P. n. nitida , while it is 1.5: 1 in P. n. decens. In addition, the median notch on upper lip is narrow in P. n. nitida , while it is wide in P. n. decens. Haigh (1965) reported P. nitida from New Zealand. In the illustration of the feeding head, the median notch was very wide, which implied that the New Zealand specimens were P. n. decens. Therefore, the present study rediscovered P. n. nitida 105 years after the original description from South Africa.

Partial mtCOX1 was amplified using DNA extracted from one specimen of P. nitida nitida . One sequence (672 bp in length) was obtained and submitted to GenBank un- der accession number OP644282.

World distribution. South Africa, Korea.

Deposition. Deposited in the collection of the National Institute of Biological Resources, Incheon, Korea ( DSEVIV 0000003943 ) .