Testudinella

Wei, Nan, De, Willem H. & Xu, Runlin, 2011, Two new brackish-water species of Testudinella (Rotifera: Testudinellidae) from Qi’ao Island in the Pearl River estuary, China, with a key to marine and brackish-water Testudinella, Zootaxa 3051, pp. 41-56 : 53-54

Key to marine and brackish-water species of Testudinella

1 Foot opening circular or semi-circular.................................................................... 2

- Foot opening a more or less wide, inverted U-shaped slit..................................................... 3

2(1) Foot opening circular, situated near centre or slightly posterior to centre of lorica; lorica almost circular; antero-ventral margin with median sinus; antero-dorsal margin almost straight to weakly convex, or three more or less pronounced shallow lobes.................................................................................. T. patina (Hermann, 1783)

- Foot opening semi-lunar, almost terminally; lorica elliptical; antero-dorsal margin convex, antero-ventral margin with broad Vshaped sinus.................................................................. T. elliptica (Ehrenberg, 1834)

3(1) Antero-ventral margin with median sinus bordered by two more or less acute projections........................... 4

- Antero-ventral margin almost straight or with median sinus not bordered by acute projections........................ 5

4(3) Antero-dorsal margin convex without median sinus; lorica in cross-section asymmetrical dorsally and ventrally, with arched dorsal margin and smaller ventral margin delimited by rounded lateral margins, not particularly compressed....................................................................................... T. crassa (Levander, 1894) sp. inq.

- Antero-dorsal margin with median sinus; lorica in cross section symmetrical both dorsally and ventrally, with rounded lateral margins, distinctly compressed dorso-ventrally............................................ T. dentata Myers, 1934

5(3) Lorica strongly elongate, ratio length/width> 2.2; antero-ventral margin almost straight, antero-dorsal margin tripartite, with median part and two lateral parts.................................................... T. elongata De Smet, 2009

- Lorica not strongly elongate, ratio length/width <1.8; antero-ventral margin with distinct median sinus, antero-dorsal margin convex, or with median sinus, or tripartite................................................................. 6

6(5) Both antero-dorsal and antero-ventral margin with median sinus or indentation..................................... 7

- Only antero-ventral margin with median sinus or indentation................................................... 8

7(6) Antero-dorsal and antero-ventral margin with broad median sinus; two acute antero-lateral projections............................................................................................... T. bicorniculata De Smet, 2009

- Antero-ventral margin with broad median sinus, antero-dorsal margin with small median indentation; antero-lateral projections absent............................................................................. T. quadrilobata sp. nov.

8(6) Antero-dorsal margin convex........................................................ T. clypeata (Müller, 1786)

- Antero-dorsal margin tripartite, with median flat or slightly convex part and two lateral parts, whether or not connected by shallow folds......................................................................................... 9

9(8) Lorica more or less elliptical, weakly truncate anteriorly; in cross-section lateral edges converging to a sharp angle; major unci teeth with more or less strongly club-shaped head; minor unci teeth parallel, rake-like............ T. obscura Althaus, 1957

- Lorica vase-shaped, distinctly truncate anteriorly; in cross section lateral edges broadly rounded; major unci teeth lanceolate; minor teeth not parallel, not rake-like..................................................................... 10

10(9) Lorica in cross-section almost symmetrical both dorsally and ventrally, more or less cruciform with broadly rounded lateral edges and rounded dorsal and ventral median part; rami with stout, quadratic alulae.................................................................................................... T. zhujiangensis Wei, De Smet & Xu, 2010

- Lorica in cross-section asymmetrical dorsally and ventrally, not cruciform, with arched dorsal margin, lateral edges broadly rounded delimiting a smaller, weakly convex median part ventrally; rami with weakly developed, more or less spiniform alulae................................................................................. T. pseudobscura sp. nov.