Biologia 65/3: 512—514, 2010 Section Zoology DOI: 10.2478/s11756-010-0048-0

Description of Lecane yatseni sp. n. (Rotifera: : ) from China

Nan Wei & Runlin Xu*

School of Life Science, Sun Yat-sen University, Guangzhou, Guangdong 510275, China; e-mail: xurunlin [email protected]

Abstract: Lecane yatseni sp. n., collected from the littoral of an artificial lake on Qi’ao island of the Pearl River estuary, Guangdong province, south of China, is described and figured. It is closely related to one of the commonest species of the , Lecane luna, resembling Lecane papuana, but distinguished by the presence of inwardly curved aculeated antero- lateral spines and broad-based spine-formed projections close to the middle of the ventral head aperture margin. Key words: Rotifera; Qi’ao island; Lecane yatseni sp. n.

Introduction

The family’s single genus, Lecane Nitzsch, 1827, is one of the most species-rich genera of Rotifera. There are more than 200 species in the genus at present (Segers 2007). They live mainly in benthic periphytic and in- terstitial habitats, and most of them live in freshwater. About 40 of them have been found in saltwaters: 21 eu- ryhaline species, 13 haloxenous species, at least seven strictly haline species have been reported, occurring in inland saline and/or marine habitats (Fontaneto et al. 2008). More than 60 species of the genus were recorded in China up to 1997, and most of the named taxa are widely distributed or cosmopolitan, with only Lecane chinesensis (Zhuge et Koste, 1996) possibly restricted to China (Zhuge et al. 1998). Further studies should be carried out, especially in marine and brackish water. In the present study, a hitherto unknown brackish water species of this genus, Lecane yatseni sp. n., is described on material from Qi’ao island of the Pearl River estuary, China.

Material and methods samples were collected with a 64 µmmeshplankton net, and preserved in 4% formaldehyde. Selection and study of rotifer specimens was done using a stereo-microscope (Shunyu SZ) and a microscope (Nikon E800). Drawings were made using a camera lucida. Fig. 1. The comparison of three species of similar lecanids: A–Lecane yatseni sp. n., ventral view; B – Not well-contracted Lecane yatseni sp. n. (Figs 1A, B) L. yatseni sp. n., ventral view; C – L. luna, ventral view (the same sampling site on Qi’ao island, November 29, 2008); D – L. papuana, ventral view, according to Segers (1995: 77, Fig. 191). Description. Parthenogenetic female: loricate Lecane. Dorsal plate narrower than ventral plate, anteriorly dorsally concave, antero-lateral corners with inwardly narrower a lot. Head aperture margins ventrally and curved aculeated spines and close to the middle of

* Corresponding author

c 2010 Institute of Zoology, Slovak Academy of Sciences Description of Lecane yatseni sp. n. from China 513

Table 1. Measurements on Lecane yatseni sp.n.(inµm; abbreviations see text).

Specimen VL l VL w DL l DL w Toe l PC l LS l

1 104.5 88.0 99.5 85.0 36.5 9.0 6.0 2 104.5 90.2 101.5 86.5 36.2 9.2 5.9 3 108.0 89.5 98.7 85.0 35.5 9.5 5.9 4 107.5 91.2 95.8 89.1 35.2 9.0 6.4 5 106.5 91.4 99.5 87.8 34.5 9.0 6.2 6 109.8 93.1 98.5 92.1 35.6 9.0 6.2 7 110.5 94.0 97.8 92.0 36.5 8.5 6.5 8 111.5 95.2 100.2 92.1 35.5 9.5 5.9 9 111.3 91.5 100.0 88.5 35.2 8.8 6.0 10 112.5 91.5 103.5 88.0 36.2 9.0 5.9

Mean 108.7 91.6 99.5 88.6 35.7 9.1 6.1 s 2.897 2.121 2.081 2.742 0.651 0.299 0.223 CV(%) 2.7 2.3 2.1 3.1 1.8 3.3 3.7

Table 2. The most important difference among Lecane luna, L. yatseni sp. n., L. papuana, L. segersi, L. curvicornis and L. rhenana. Modified from (Segers 1995) and (Sanoamuang 1996).

Morphological L. luna L. yatseni sp. n. L. papuana L. segersi L. curvicornis L. rhenana characteristics

Shape of antero- sharp, broad- sharp, broad- semicircular sharp, broad- sharp, narrow- sharp, narrow- lateral corners based spines based inwardly projections based, inwards- based spines based spines curved spines directed spines Shape of ventral concave promi- concave promi- concave promi- concave promi- variable: broadly straight or head aperture nently, antero- nently with nently, antero- nently, V- or U-shaped, slightly concave margin lateral corners 2 pairs of lateral corners antero-lateral straight or with broad-based projections with semicircu- corners with slightly convex spines lar projections, sharp, inwards- median with a directed spines, sinus median with a sinus Shape of dorsal concave concave straight straight variable: broadly straight or head aperture prominently prominently V- or U- shaped, slightly convex margin straight or slightly convex Lateral margins yes yes yes yes no yes reach or not reach the head aperture

the head aperture margins with a pair of broad-based PC l: pseudoclaw length, LS l: lateral spine length. spine-formed projections on ventral plate. Dorsal plate VL l: 104–113(109), VL w: 88–96(92), DL l: 95– smooth or with simple ornamented protuberance, al- 104(100), DL w: 85–93(89), Toe l 34–37(36), PC l: 8– most circular in well-contracted , frequently 10(9), LS l: 5–7(6). with anterior dome. Lateral margins reach head aper- ture. Ventral plate longer than wide, smooth or with Material examined. An artificial lake on Qi’ao island bor- ders on Qi’ao – Dangan of Zhuhai provincial mangrove nat- simple ornamented protuberance. Transverse fold com- ◦ ◦ plete. Lateral margins smooth, strongly curved. Lateral ural reserve (22 26 N, 113 38 E), Guangdong province, China, July 27, 2008. Female holotype (ROT00001) and two sulci deep. Foot plate broad, coxal plates rounded trian- paratypes (ROT00002, ROT00003) deposited in the Biol- gular. Prepedal fold broad, short, distally with rounded ogy Museum of Sun Yat-sen University, Guangdong, China. margin. Foot pseudosegment trapezoidal, not project- Another paratype (ANSP 2073) in the Academy of Natural ing. Toes relatively short, parallel-sided, bearing incom- Sciences of Philadelphia. pletely separated, needle-like pseudoclaws and acces- sory claws. Etymology. The species is named after Sun Yat-sen Male and resting egg unknown. (Sun Zhongshan) who is the founder of the author’s alma mater (Sun Yat-sen University), for his devotion Measurements. All measurements (Table 1) are in to Chinese revolution. µm. Abbreviations are as follows: VL l: ventral lorica length, VL w: ventral lorica width, DL l: dorsal lorica Differential diagnosis. Lecane yatseni sp. n. (Figs length, DL w: dorsal lorica width, Toe l : toe length, 1A, B) is closely related to one of the commonest species 514 N. Wei &R.Xu

Table 3. Metazoan zooplankton recorded from the sampling site on Qi’ao island of the Pearl River estuary, China, during this study. *New record for China.

Rotifera Copepoda

Brachiouus angularis Gosse, 1851 Acartia southwelli Sewelli, 1914 nilsoni Ahlstrom, 1940 Halicyclops sp. M¨uller, 1786 Limnoithona sinensis Burckhardt, 1913 Brachionus rotundiformis Tschugunoff, 1921 Schmackeria forbesi Poppe et Richard, 1890 Colurella colurus Ehrenberg, 1830 Sinocalanus laevidactylus Shen et Tai, 1964 *Colurella sanoamuangae Chittapun, Pholpunthin et Segers, 1999 Cladocera Euchlanis dilatata Ehrenberg, 1832 Alona sp. Hexarthra fennica Levander, 1892 Diaphanosoma sp. Lecane bulla Gosse, 1851 Larvae *Lecane donneri Chengalath et Mulamoottil, 1974 Bivalvia larvae Lecane grandis Murray, 1913 Brachyura larvae Lecane stenroosi Meissner, 1908 Fishes larvae Rotaria sp. Gastropoda larvae Synchaeta sp. Macrura larvae Tripleuchlanis plicata (Levander, 1894) Polychaeta larvae

of the genus, L. luna (M¨uller, 1776) (Fig. 1C), superfi- Acknowledgements cially resembling L. papuana (Murry, 1913) (Fig. 1D). The presence of two pairs of broad-based spines on the The authors wish to thank Dr. H. Segers (Royal Belgian concave ventral head aperture margin characterise the Institute of Natural Sciences, Belgium) for the confirma- species. The first pair of spines in antero-lateral corners tion of the new species, great advice and providing data on Lecanidae. We sincerely thank graduate students Xin is much longer, aculeated and inwardly curved. The sec- Ye and Changfu Wang for their helps with sampling. This ond pair of spines close to the middle of the ventral work was supported by the National Nature Fund of China head aperture margin is less prominent, it can be easily (U0633002). overlooked. It differs from L. luna by the spines on anterior References margin of ventral plate, from L. papuana by the in- wardly curved aculeated antero-lateral spines, and by Fontaneto D., De Smet W.H. & Melone G. 2008. Identification its concave dorsal head aperture margin. key to the genera of marine worldwide. Meiofauna Lecane rhenana (Hauer, 1929) is excluded based on Marina 16: 75–99. the characteristics of Lecane yatseni. sp. n. following Sanoamuang L. 1996. Lecane segersi n. sp. (Rotifera, Lecanidae) from Thailand. Hydrobiologia 339: 23–25. DOI 10.1007/ the classification scheme of Segers (1995). There are BF00008909 also some superficial resemblances with L. curvicornis Segers H. 1995. Rotifera 2. The Lecanidae (Monogononta), pp. 1– (Murray, 1913) and L. segersi (Sanoamuang, 1996), but 226. In: Dumont H.J. (eds), Guides to the Identification of the the species can not be confused. Table 2 show the most Microinvertebrates of the Continental Waters of the World 6, SPB Academic Publishing bv, The Hague, The Netherlands. important difference among Lecane luna, L. yeatseni Segers H. 2007. Annotated checklist of the rotifers (Phylum Ro- sp. n., L. papuana, L. segersi, L. curvicornis and L. tifera), with notes on nomenclature, and distribu- rhenana. tion. Zootaxa 1564: 1–104. Zhuge Y., Huang X. & Koste W. 1998. Rotifera recorded from China, 1893–1997, with remarks on their composition Distribution and ecology. Lecane yatseni sp. n. and distribution. Int. Rev. Hydrobiol. 83: 217–232. DOI might be a rare warm-stenotherm species. So far, it 10.1002/iroh.19980830305 has been found on July 27, 2008 only from the sam- ◦ Received September 9, 2009 ples collected in the lake (temperature 33 C, salin- Accepted December 10, 2010 ity 12‰), which is a distinct brackish water body. However, a closely related species, L. luna, a common species preferring warmer waters, was occurring in the same site later in the year (November 29, 2008; tem- perature 17 ◦C; salinity: 14‰). A list of accompanying metazoan zooplankton fauna is presented in Table 3.