Encentrum incisum Wulfert, 1936

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

1. Encentrum incisum Wulfert, 1936 ( Fig. 1 A-C)

Encentrum incisum Wulfert, 1936, pp. 423-425 , figs. 16, 16 a-c (cited from De Smet, 1997); Donner, 1970, p. 226, figs. 13e-f; Koste, 1978, p. 495, pl. 176, figs. 1 a-e; De Smet, 1997, pp. 182-184, figs. 503-507, pl. 31, figs. 1-5; Jersabek, 1998, pp. 67-69, figs. 21-24.

Material examined. 2 specimens, a mountain in Gyo-1- dong, Gangneung-si, Gangwon-do (leaf litter, Min Ok Song), 26 Feb, 2013.

Description. Body spindle-shaped. Head about 1/2 of trunk length. Integument thin, smooth, transparent and with transverse folds defining head, trunk and foot. Rostrum short, V-shaped ventrally and decurved. Foot conical, short and about 1/6 of trunk length. Toes short, slen- der, about same length as foot, parallel-sided until half of length and tapering to pointed tips.

Trophi forcipate type. Rami outline round pyriform, each getting broader until 1/3 from base, abruptly tapering into slender and incurved single tooth after preuncinal tooth; preuncinal tooth long, narrow and sharp, emerging from outer margin of ramus ventrally and projecting towards axis of trophi; another preuncinal tooth present between apical tooth and ventral preuncinal tooth. Fulcrum short, about 2/5 of manubria length. Intramallei short, with round base and tapering ends. Unci stout, single-toothed, about 3/5 of manubria length. Manubria rod-shaped, long, longer than 2-fold of fulcrum length, incurved, knobby distally and expanded proximally.

Body length 202 μm. Toe length 19 μm.

Distribution. Austria, Germany, Russia and Korea.

Remarks. E. incisum has been reported only from Austria, Germany and Russia before the present study ( De Smet, 1997). It is similar to E. martoides Fott, 1960 except the following differences: (1) Foot of E. incisum has a single pseudosegment, while that of E. martoides has two pseudosegments, (2) Inner margin of rami is outcurved near posterior 1/ 3 in E. incisum , while it is otherwise in E. martoides , and (3) Gastric glands of E. incisum are not fused nor connected with brain, while they are fused dorsally and connected with brain in E. martoides ( De Smet, 1997) .

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).