Philodina clypeata, Song & Lee, 2020

Song, Min Ok & Lee, Chang-Ho, 2020, Descriptions of two new species of Philodina (Rotifera, Bdelloidea), with notes on seven rare bdelloids from Korea, Zootaxa 4772 (2), pp. 253-276 : 258-260

Philodina clypeata new species

Figures 1 and 2

urn:lsid:zoobank.org:act:68C564BF-EB53-4D84-A0CF-934C89F45773

Holotype and paratypes. On permanent slides, deposited in the collection of the National Institute of Biological Resources, Incheon, Korea (holotype: FKRUIV0000000917; two paratypes: FKRUIV0000000918, and FK- RUIV0000000919 ) .

Type locality. Moss valley area in Mugeon-ri , Dogye-eup , Samcheok-si, Gangwon-do, Korea. GPS coordinates based on WGS84 datum 37°16'17.9"N / 129°04'25.0"E .

Material. Five specimens sorted out from leaf litter and mosses around Moss valley, collected by Min Ok Song and Chang-Ho Lee on 28 April, 2018.

Differential diagnosis. Philodina clypeata n. sp. is most similar to Philodina rugosa coriacea Bryce in the

morphologies of feeding head, granulated trunk and spurs; however, this new species can be distinguished from P. rugosa coriacea by the following characteristics: (1) this new species does not have eye spots, while P. rugosa coriacea has two cerebral eye spots, (2) the trunk of this new species is granulated and sculptured with polygonal patterns dorsally, while that of P. rugosa coriacea is granulated and with wavy longitudinal ridges, (3) the first trunk pseudosegment of the new species has a shield-shaped sculptured area dorsally, which is absent in P. rugosa coriacea , (4) the first foot pseudosegment of P. rugosa coriacea has a transverse ridge with wavy margin dorsally, while that of the new species doesn’t have it, (5) the interspace between spurs is three times as wide as spur base width in this new species, while it is slightly wider than spur base width in P. rugosa coriacea , and (6) the posterior part of the spur pseudosegment is expanded in the new species, while it is otherwise in P. rugosa coriacea .

The most prominent characteristics of this new species are the absence of eye spots, the granulated trunk with dorsal polygonal patterns, and a shield-shaped sculptured area on the dorsal part of first trunk pseudosegment. P. rugosa rugosa Bryce and its two subspecies-level taxa, coriacea and callosa, are the only Philodina species with highly granulated trunk similar to that of this new species; however, all of them have two cerebral eye spots, and none of them has sculptured trunk with polygonal patterns dorsally.

Description. No eye spots. Head and neck with smooth integument, while trunk with granulated integument. Rostral lamella with two lobes and each lobe round; interspace between lobes narrower than 1/3 of each lobe width. Rostrum as long as it is wide; the ratio of rostrum width to smallest neck width about 1: 1.9. Corona wider than cingulum; the ratio of corona width to cingulum width about 1.16: 1–1.17: 1. Sulcus slightly narrower than pedicel width. Pedicels short. Upper lip arched, with two median lobes and with wide depression between two lobes; much lower than trochal discs and higher than sulcus base; interspace between lobes concave and about 3/5 of sulcus width. Cingulum pad slightly wider than cingulum. Pharyngeal tube much shorter than trophi length. Dental formula 3/3. Trunk highly granulated, sculptured, and covered with detritus; granules rather big and dense; diameter of granules about 1.3–2.7 μm; the first trunk pseudosegment with a shield-shaped sculptured area dorsally; granules fused and formed half round and rough strips of various lengths on longitudinal ridges of trunk; the second, third and fourth trunk pseudosegments with polygonal patterns dorsally; fourth pseudosegment expanded and abruptly narrowed to rump; preanal pseudosegment much narrower than fourth pseudosegment and with rather squarish posterolateral margins; anal pseudosegment much narrower than preanal pseudosegment. Foot with smooth integument; with four pseudosegments; posterior part of spur pseudosegment expanded. Spurs thin, short finger-shaped and with wide interspace; middle part of spurs rather plump and abruptly tapering to knobby and blunt tips; interspace width about three times as wide as spur base width.

Measurements. Total length in creeping 260–316 μm. Total length in feeding 193–253 μm. Rostrum width 20–24 μm. Corona width 51–63 μm. Cingulum width 44–54 μm. Cingulum pad width 46–59 μm. Greatest neck width in feeding 45–57 μm. Greatest neck width in creeping 51–56 μm. Greatest trunk width in feeding 97–117 μm. Greatest trunk width in creeping 56–84 μm. Trophi length 15–19 μm. Spur length 8–10 μm.

Distribution. The new species is known only from its type locality.

Etymology. The specific name clypeata is an adjective, referring to the shield-shaped sculptured area which is on the first trunk pseudosegment dorsally.

Figures

FIGURE 1. Philodina clypeata n. sp. (a) creeping, dorsal view; (b) feeding head and neck, dorsal view; (c) foot, spurs and toes, dorsal view; (d) spurs and toes, ventral view (scale bars: a = 50 μm; b = 25 μm; c–d = 10 μm).

FIGURE 2. Light microscopy photographs of Philodina clypeata n. sp. (a) feeding head, neck and trunk, dorsal view; (b) feeding, dorsal view; (c) spurs and toes, ventrolateral view; (d) foot, spurs and toes, ventral view (scale bars: a = 25 μm; b = 50 μm; c–d = 10 μm).