Sternaspis Otto, 1821

Salazar-Vallejo, Sergio I., 2017, Cymonomus curvirostris Sakai 1965, Zoological Studies (Zool. Stud.) 56 (32), pp. 16-16 : 13-15

Key to species of Sternaspis Otto, 1821

(modif. after Salazar-Vallejo 2014b)

1. Shield fan with a distinct median notch ....................... 2

- Shield fan continuous, without distinct median notch ..... ................................................................................... 16

2(1). Shield with radial ribs and concentric lines distinct ..... 3

- Shield with radial ribs distinct, concentric lines barely visible ........................................................................ 13

3(2). Fan with median notch shallow ................................... 4

- Fan with median notch deep; shields usually with concentric bands ......................................................... 7

4(3). Shield with distinct pigmented concentric bands ......... 5

- Shield without pigmented concentric bands ................ 6

5(4). Fan with posterior margin straight, smooth, barely crenulated ....................................................................... ............... S. affinis Stimpson, 1864 (NE Pacific Ocean).

- Fan with posterior margin curved, slightly projected posteriorly, crenulated to dentate ............... S. chinensis Wu, Salazar-Vallejo & Xu, 2015 (Bohai, Yellow and East China seas)

6(4). Main rib barely projected, lateroposterior depressions shallow ............................................................................ S. scutata ( Ranzani, 1817) (Mediterranean Sea and NE Atlantic Ocean)

- Main rib markedly projected, lateroposterior depressions deep ............................................................................... S. liui Wu, Salazar-Vallejo & Xu, 2015 (Yellow Sea)

7(3). Shield with posterior corners distinct in frontal view .... 8

- Shield with posterior corners poorly defined in frontal view ............................................................................. 9

8(7). Radial ribs and concentric lines distinct, well defined; body whitish to grayish .... ............................................... S. costata von Marenzeller, 1879 (NW Pacific Ocean)

- Radial ribs and concentric lines barely defined; body brownish ......................................................................... .... S. sendalli Salazar-Vallejo, 2014b (Antarctic Ocean)

9(7). Anterior keels usually exposed .................................. 10

- Anterior keels rarely exposed; fan barely projecting posteriorly beyond posterolateral corners ................. 11