Philodina verrucosa, 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 : 261-263

Philodina verrucosa new species

Figures 3 and 4

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Holotype and paratypes. On permanent slides, deposited in the collection of the National Institute of Biological Resources, Incheon, Korea (holotype: FKRUIV0000005591; two paratypes: FKRUIV0000005592, and FK- RUIV0000005593 ) .

Type locality. Jangyeol-ri , Bukpyeong-myeon , Jeongseon-gun, Gangwon-do, Korea. GPS coordinates based on WGS84 datum 37°27'16.8"N 128°40'55.4"E .

Material. Eight specimens sorted out from mosses around a mountain in Jangyeol-ri, collected by Min Ok Song and Chang-Ho Lee on 30 June, 2018.

Differential diagnosis. This new species is similar to Philodina rugosa coriacea Bryce in the morphology of granulated trunk and spurs; however, this new species differ 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 upper lip is broadly triangular and with rounded median lobe in this new species, while that is bilobed and with wide median depression between lobes in P. rugosa coriacea , (3) the trochal discs of new species look rather round in dorsal view since they are slightly inclined dorsally, while those of P. rugosa coriacea are not inclined dorsally, (4) this new species has coarsely granulated hemispherical processes on the trunk when feeding, while P. rugosa coriacea doesn’t have hemispherical processes on its trunk when feeding, (5) the first foot pseudosegment of P. rugosa coriacea has a transverse ridge with wavy margin dorsomedially, while that of the new species doesn’t have any protuberance dorsally, and (6) the spurs are twice as long as spur base width in the new species, while they are much longer than double of spur base width in P. rugosa coriacea .

Philodina verrucosa n. sp. is easily distinguished from its congeners by the coarsely granulated hemispherical processes on the trunk when feeding. There are several Philodina species with highly granulated trunk such as P. corrugata Song & Lee , P. rugosa rugosa Bryce and its two subspecies-level taxa, coriacea and callosa, and P. scabra Milne ; however, none of them has the wart-shaped granulated protuberances on trunk dorsally and laterally when feeding.

Description. No eye spots. Head and neck smooth. Rostral lamella bilobed and each lobe round; short and much narrower than width of anterior end of rostrum. Rostrum as long as it is wide. Corona as wide as or slightly wider than cingulum. Trochal discs slightly inclined dorsally and rather round in dorsal/ventral view. Sulcus much narrower than pedicel width. Pedicels short. Upper lip broadly triangular and with rounded median lobe; higher than sulcus base; much lower than trochal discs; as high as disc retractor. Disc retractor convex. Cingulum as wide as cingulum pad; with slight expansion laterally. Cingulum pad with a bump laterally. Pharyngeal tube shorter than trophi length. Dental formula 2/2. Trunk highly granulated and spindle-shaped in creeping; granulated hemispherical processes on the second, third and fourth trunk pseudosegments dorsally and laterally in feeding; these wartshaped processes become lobulated longitudinal ridges and some flat dome-shaped protuberances on trunk when stretched or creeping; first trunk pseudosegment cylindrical and as wide as the greatest neck width in creeping; anal pseudosegment smooth and tapering to foot. Foot short, smooth, and with four pseudosegments; about 1/8–1/7 of total body length in creeping. Spurs conical and narrow; twice as long as its width; spur length about a half of spur pseudosegment width; interspace slightly wider than spur base width.

Measurements. Total length in creeping 177–247 μm. Total length in feeding 143–152 μm. Rostrum width 16–17 μm. Corona width 35–41 μm. Cingulum width 34–40 μm. Cingulum pad width 35–40 μm. Antenna length 16–18 μm. Greatest neck width in creeping 39–41 μm. Greatest trunk width in feeding 51–70 μm. Greatest trunk width in creeping 49–56 μm. Trophi length 13–14 μm. Spur length 5.3–7.6 μm.

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

Etymology. The specific name verrucosa is an adjective, referring to the wart-shaped hemispherical processes on the trunk pseudosegments dorsally and laterally in feeding.

Barcode. GenBank accession number MN746287

Figures

FIGURE 3. Philodina verrucosa n. sp. (a) creeping, dorsal view; (b) feeding, dorsal view; (c) foot, spurs and toes, ventral view (scale bars: a = 50 μm; b = 25 μm; c = 10 μm).

FIGURE 4. Light microscopy photographs of Philodina verrucosa n. sp. (a) feeding, dorsal view; (b) creeping, dorsolateral view; (c) trunk, dorsal view; (d–e) foot, spurs and toes, ventral view (scale bars: a–c = 50 μm; d–e = 10 μm).