Encentrum uncinatum ( Milne, 1886 )

Song, Min Ok, 2014, Eight new records of monogonont and bdelloid rotifers from Korea, Journal of Species Research 3 (1), pp. 53-62 : 54-55

2. Encentrum uncinatum ( Milne, 1886) ( Fig. 1 D-F)

Diglena uncinata Milne, 1886, p. 141 , pl. 2, figs. 1, 2, 8.

Dicranophorus uncinatus : Donner, 1964, pp. 283-284, figs. 20a-d; Koste, 1978, p. 466, pl. 169, figs. 12a-d, pl. 172, figs. 7a-d.

Encentrum uncinatum : De Smet, 1997, p. 161, figs. 434- 440, pl. 25, figs. 1-4.

Material examined. 8 specimens, a mountain in Gyo-1- dong, Gangneung-si, Gangwon-do (leaf litter, Min Ok Song), 26 Feb, 2013.

Description. Body elongate, half-moon-shaped and flattened laterally. Trunk subcylindrical, rather flat ventrally, convex dorsally, and with laterodorsal longitudinal folds. Transverse folds defining body into head, trunk and foot. Integument thin, smooth and transparent, but body outline rather fairly constant. Head big, about 2/5 of body length except toes. Eye-spots absent. Rostrum large, broad, triangular and decurved. Foot conical and 1/3 of trunk length. Toes sword-shaped, long and about 2-fold of foot length. Retrocerebral sac and duct present. Trophi forcipate type. Rami outline pyriform, each sickle-shaped and terminating into a long, tapering and incurved tooth; a needle-like preuncinal tooth emerging from outer margin and projecting towards axis of trophi at about 1/3 from a tip. Fulcrum short, about 1/3 of ramus length. Unci single-toothed, about 3/5 of manubria length. Intramallei short, with round base and tapering ends. Supramanubria large, thin, rhomboid-ovate and tapering into short needle-like tips distally. Manubria long, about 3-fold of fulcrum length, rod-shaped, curved and knobby distally and proximally.

Body length 250 μm, toe length 70 μm; trophi length 30 μm.

Distribution. Cosmopolitan, but, not recorded from Korea before.

Remarks. De Smet (1997) proposed that the genus Dicranophorus should only include species characterized by: elongate basal and subbasal chambers forming a dense conglomerate; basal chamber opening laterally; subbasal chamber opening ventrally; intramallei absent; unci single-toothed, interlocking with dorsal apical ramus tooth or its cardal apophyse and a cardal apophyse ventrally. Since the trophi parts of Dicranophorus uncinatus have characteristics different from those mentioned above, De Smet (1997) transferred it to genus Encentrum .

Figures

Fig. 1. Encentrum incisum Wulfert, 1936. A. lateral view. B. ventral view. C. trophi, ventral view. Encentrum uncinatum (Milne, 1886). D. ventral view. E. lateral view. F. trophi, ventral view. Cephalodella innesi Myers, 1924. G. ventral view. H. lateral view. I. trophi, ventral view(Scales: A, B, D, E=50μm; C, F=10μm; G-I=20 μm).