Chevalia

Souza-Filho, Jesser F., Souza, Ana Maria T. & Valério-Berardo, Maria Teresa, 2010, Six new species of the genus Chevalia Walker, 1904 (Amphipoda, Corophiidea, Chevaliidae) from Brazilian waters, with a key to world species of the genus, Zootaxa 2713, pp. 25-51 : 50

Key to world species of Chevalia

1. Pereopod 7 with basis rectangular .............................................................................................................................. 2

- Pereopod 7 with basis ovate........................................................................................................................................ 8

2. Gnathopod 2 palm transverse ...................................................................................................................................... 3

- Gnathopod 2 palm oblique............................................................................................................................................ 7

3. Basis of pereopod 7 distally expanded, with a protuberant posteroventral corner ....................................................... 4

- Basis of pereopod 7 not distally expanded, without a protuberant posteroventral corner ........................................... 6

4. Mandible palp more than 3 X length of body of mandible, article 2 longer than article 3; dactylus of gnathopod 2 more than half length of propodus and with inner proximal hump ............................................................................. 5

- Mandible palp less than 3 X length of body of mandible, article 2 and 3 subequal in length; dactylus of gnathopod 2 less than half length of propodus and without inner proximal hump ........................................... C. tenuis Myers, 2009

5. Palm of gnathopod 2 defined by acute projection and weakly sinuose; basis of pereopod 7 about 3.3 X longer than wide ........................................................................................................................................ C. mexicana Pearse, 1913

- Palm of gastropod 2 defined by square dentate projection and with a large crenulate “U”–excavation near hinge of dactylus; basis of pereopod 7 about 2 X longer than wide ............................................................... C. caetes sp. nov.

6. Accessory flagellum 2–articulate; coxa 1 with anteroventral angle not produced forward; gnathopod 2 with carpus about one half of propodus length ............................................................................................ C. pacifica Myers, 1995

- Accessory flagellum 3–articulate; coxa 1 with anteroventral angle produced forward; gnathopod 2 with carpus as long as propodus length ................................................................................................................ C. thomasi sp. nov.

7. Anteroventral corner of coxa 1 attenuate and sharp; basis of pereopod 7 with a projection on posteroventral corner. ................................................................................................................................. C. aviculae complex Walker, 1904

- Anteroventral corner of coxa 1 blunt; basis of pereopod 7 without a projection on posteroventral corner .................. ............................................................................................................................................ C. inaequalis ( Stout, 1913)

8. Posterodorsal margins of pereon and pleon with a line of +10 long simple setae in adults, in subadults about 6 long simple setae ........................................................................................................................................ C. setosa sp. nov.

- Posterodorsal margins of pereon 6 and/or 7 and pleon 1–3 with a pair of long simple setae, in subadults about 6 long simple setae.................................................................................................................................................................. 9

9. Mandible palp elongate, more than 3 X length of body of mandible ........................................ C. marajoara sp. nov.

- Mandible palp short, 2X length of body of mandible ............................................................................................... 10

10. Carpus of pereopods 5–7 with 4 submarginal robust setae on anterodistal corner; uropods 1–2 with long setae on the dorsal margin of peduncles; epimera 1–3 without notch on posteroventral corner ........ C. hirsuta Lazo-Wasem, 1999

- arpus of pereopods 5–7 with 2 submarginal robust setae on anterodistal corner; uropods 1–2 without setae on the dorsal margin of the peduncles; epimera 1–3 with a notch on posteroventral corner ............................................... 11

11. Gnathopod 2 coxal gill short, 1/2 length of basis; pereopod 3 of female oostegite absent or very short; telson with distal margin bearing a middle process...................................................................................................................... 12

- Gnathopod 2 coxal gill about 1/2 of basis; female oostegite of pereopod 3 at least one half the length of the basis; telson with distal margin convex and lacking middle process ............................................................ C. convexa sp. nov.

12. Female oostegite of pereopod 3 very reduced; uropod 1 inner ramus with 9 serrate spines, extending on almost half length of medial margin; male gnathopod 2 palm defined by acute projection and dactylus the same length of palm ....................................................................................................................................................... C. anomala sp. nov.

- Female oostegite of pereopod 3 absent; uropod 1 inner ramus with 14 serrate spines, extending on almost 2/3 length of medial margin; male gnathopod 2 palm defined by rounded projection and dactylus shorter than palm ................. ......................................................................................................................... C. carpenteri Barnard & Thomas, 1987