Brachionus cf. caudatus var. indica Novotná-Dvořáková, 1963

Wei, Nan, Jersabek, Christian D. & Yang, Yufeng, 2019, Rotifers from China (Western Guangdong Province), with description of Lecane zhanjiangensis sp. nov. (Rotifera: Monogononta: Lecanidae), Zootaxa 4603 (1), pp. 66-80 : 66-80

Brachionus cf. caudatus var. indica Novotná-Dvořáková, 1963

( Fig. 4 )

The specimens found in the littoral zone of Moyangjiang River ( Fig. 4A ; Tab. 1 ), and in another three localities in Changde City, Hunan Province, on 16 September 2017 ( Fig. 4 B–4E), largely conform to the description of Brachionus caudatus var. indica Novotná-Dvořáková, 1963 , and only differ in minor aspects. The antero-lateral dorsal spines are almost as long as the median spines in specimens from Moyangjiang River and Changde, while they are longer than the median ones in B. caudatus var. indica . Moreover, the ventral median sulcus of the anterior aperture is much deeper in specimens from Moyangjiang River ( Fig. 4A ) if compared to B. caudatus var. indica and specimens from Changde City ( Fig. 4B ). Our specimens also show a high similarity with Brachionus caudatus f. majusculus Ahlstrom, 1940 from Florida, from which they differ by ventrally directed posterior spines ( Fig. 4E ). These are inserted in the same plane as the body axis in B. caudatus f. majusculus. Another similar infraspecific taxon that has been described within the caudatus -complex and that requires attention here is Brachionus caudatus f. apsteini Fadeev, 1925. As in var. indica , posterior spines arise at an angle ventrally in f. apsteini, but are relatively shorter. Previous records of a variant of B. caudatus , sub B. caudatus f. apsteini Fadeev, 1925, as a common taxon in the Southwestern Islands of Japan, show a striking resemblance to our B. cf. caudatus var. indica , and most likely concern the same taxon ( Sudzuki, 1992: Plate XII: Figs 2–7 ). Further specimen material needs to be examined by also including molecular methods to determine the taxonomic status of these supposedly infraspecific taxa within the highly variable morphospecies B. caudatus Barrois & Daday, 1894 .

Figures

FIGURE 2. Lecane zhanjiangensis sp. nov. A. Habitus, dorsal view. B. Habitus, ventral view. C. Not well-contracted head with spines, dorsal view. D. Light microscope photograph of Holotype, ventral view. E. Habitus, dorsal view, U.S. specimen modified from Turner (1996). Arrows indicate the spines on the outside of head. Scale bars: A–E: 50 µm.

FIGURE 3. Lecane zhanjiangensis sp. nov., scanning electron microscope photographs of trophi. A. Complete set, ventral view. B. Complete set, dorsal view. C. Unci and rami, ventral view. D. Unci and rami, dorsal view. Scale bar: 5 µm.

FIGURE 4. Light microscope photograph of Brachionus cf. caudatus var. indica. A, C. Habitus, dorsal view. B. Anterior lorica aperture, ventral view. D. Foot opening, ventral view. E. Habitus, lateral view. Scale bar: 50 µm. Specimen in Fig. 4A from Moyangjiang River, Yangjiang, Guangdong Province and specimens in Fig. 4A–4E from Changde, Hunan Province.

FIGURE 5. Light microscope photograph of Ptygura libera. A. Habitus, dorsal view. B. Habitus, lateral view. C–E. Anterior part of body, lateral view. F. Peduncle (attachment stalk) and gelatinous tube. Arrows show the excreting anus. Scale bar: A–F: 50 µm.

FIGURE 6. Ptygura libera, scanning electron microscope photographs of trophi. A. Complete set, frontal view. B. Complete set, caudal view. C. Unci and rami, frontal view. D. Unci and rami, caudal view. Scale bar: A–D: 2 µm.

FIGURE 7. Light microscope photograph of Ptygura thalenoiensis. A. Habitus, lateral view. B. Peduncle and gelatinous tube, lateral view. C. Corona, lateral view. D, F. Dorsal hooks and cylindrical projection, lateral view. E. Dorsal hooks and cylindrical projection, dorsal view. G, H. Corona, frontal view. Arrows show the cylindrical projection with elongate cilia in Fig. 5C and the dorsal hooks and cylindrical projection in Fig. 5D–5F. Scale bar: A–C, E–H: 50 µm; D: 10 µm.