Habrotrocha changhoi, Song & Lee, 2024

Song, Min Ok & Lee, Chang-Ho, 2024, Descriptions of three new species of Philodinida (Rotifera, Bdelloidea) from Korea, Zootaxa 5493 (1), pp. 36-54 : 39-41

Habrotrocha changhoi n. sp.

Figures 1 and 2

urn:lsid:zoobank.org:act:15FDB251-BFC1-4A05-B3FF-4CD2B6F95EA4

Holotype and paratypes. On permanent slides, deposited in the collection of the National Institute of Biological Resources, Incheon, Korea (holotype: NIBRIV0000879459; two paratypes: NIBRIV0000879460 and NIBRIV0000879461) .

Type locality. Galcheon-ri , Seo-myeon , Yangyang-gun, Gangwon-do, Korea. GPS coordinates based on WGS84 datum 37°54'3.0"N / 128°30'6.4"E .

Material. Five specimens sorted out from mosses on rocks, collected by Min Ok Song and Chang-Ho Lee on 20 June, 2020.

Differential diagnosis. This new species is very close to Habrotrocha constricta (Dujardin, 1841) in the general morphology. However, this new species can be distinguished from H. constricta by the following characteristics: (1) this new species has five small humps on preanal pseudosegment dorsally, while H. constricta doesn’t have any projections on the dorsal part of preanal pseudosegment, (2) this new species has a thick and plump rim on the anal pseudosegment posterodorsally, which is absent in H. constricta , (3) the cingulum pad of this new species has a small projection on each lateral margin anteriorly, while that of H. constricta doesn’t have any projection on it, (4) the median lobe of the upper lip of this new species is rounded triangular or rounded pentagon-shaped because of the slight constriction at the base, while that of H. constricta is simply arched, narrow bell-shaped, or rarely bilobed, and (5) the egg of this new species is without humps, while that of H. constricta has 2–3 humps or is covered with many humps ( Donner 1965).

Description. Body brownish and finely granulated. Rostrum slightly longer than its width. Rostral lamella bilobed and very short; slightly narrower than rostrum width. Corona slightly narrower than cingulum; the ratio of corona width to cingulum width about 0.97: 1. Each end of cingulum slightly convex. Cingulum pad slightly wider than cingulum; the ratio of cingulum pad width to cingulum width about 1.07: 1; with a small projection on each lateral margin anteriorly; projection looking round or rather pointed depending on the position as well as the degree of contraction and relaxation of the feeding head ( Figs. 1b , 2a, 2f ); lateral margins concave in the middle and somewhat expanded posteriorly. Pedicel short; tufts of cilia on the outer lateral margins of pedicel proximally. Sulcus much narrower than pedicel width. Upper lip arched, rimmed and with narrow median lobe; median lobe rounded triangular or rounded pentagon-shaped depending on the position of the feeding head; slightly lower than trochal discs. Trochal discs slightly inclined inwardly.Antenna short; slightly shorter than 1/3 of height of antenna pseudosegment in feeding ( Fig. 2e ); lateral margins of pseudosegment bearing antenna round. Pharyngeal tube shorter than trophi length. Teeth 8/8. Trunk plump medially in feeding and cylindrical in creeping; abruptly narrowed to rump; lateral margins squarish posteriorly in creeping. Rump much narrower than trunk in feeding; gradually tapering to foot. Preanal pseudosegment with a hump anterodorsally and five small hemispherical processes posterodorsally ( Figs. 1a–c , 2a–c ); five processes arranged in semicircle. Anal pseudosegment with thick and plump rim posteriorly. Foot narrower than rump and tapering gradually to pseudosegment bearing toes; with four pseudosegments; foot very short and about 1/14–1/11 of total body length in creeping. Three toes short and small. Spurs conical and without interspace; lateral margins of spurs tapering to dull and knobbed ends; outer margins straight and each internal margins with a swelling proximally. Egg oval and without humps.

Measurements. Total length in creeping 235–263 μm. Total length in feeding 155–163 μm. Corona width 28–29 μm. Cingulum width 29–30 μm. Cingulum pad width 31–32 μm. Trophi length 16 μm. Antenna length 9–12 μm. Greatest trunk width in creeping 37–41 μm. Greatest trunk width in feeding 63–65 μm. Foot length in creeping 19–22 μm. Spur length 6–7 μm.

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

Etymology. The new species is named after Dr. Chang-Ho Lee, Professor of the Department of Biology of Gangneung-Wonju National University, in recognition of his continuous contribution to bdelloid taxonomy projects, especially in CO1 gene sequencing and sampling.

Figures

FIGURE 1. Habrotrocha changhoi n. sp. (a) creeping, dorsal view; (b) feeding, dorsal view; (c) rump, foot, spurs and toes, ventrolateral view; (d) foot and spurs, dorsal view (scale bars: a–b = 50 μm; c = 20 μm; d = 10 μm).

FIGURE 2. Light microscopy photographs of Habrotrocha changhoi n. sp. (a) feeding, dorsal view (arrows pointing at a small projection on each anterolateral margin of cingulum pad); (b) rump, foot and spurs, lateral view; (c) rump, foot and spurs, ventrolateral view; (d) foot and spurs, dorsal view; (e) feeding head and neck, lateral view; (f) feeding head and neck, dorsal view (arrows pointing at a small projection on each anterolateral margin of cingulum pad) (scale bars: a = 50 μm; b–c = 20 μm; d = 10 μm; e–f = 20 μm).