Cerapus, Say, 1817

Berents, Penelope B., 2023, New Species of Cerapus from Australian Waters (Amphipoda: Senticaudata: Ischyroceridae), Records of the Australian Museum (Rec. Aust. Mus.) 75 (4), pp. 381-403 : 382

Key to Australian species of Cerapus (male)

1 Recurved spines on telson in 2 rows ......................................................................................... 2 —— Recurved spines on telson in 3 rows .................................................. Cerapus nudus Just, 2009

2 Antenna 2 longer than antenna 1 ............................................................................................... 3 —— Antenna 2 equal to or shorter than antenna 1 ............................................................................ 4

3 Coxa 6 with setal fringe ............................................................ Cerapus moonamoona sp. nov. —— Coxa 6 lacking setal fringe ............................. Cerapus alquirta (Barnard & Drummond, 1981)

4 Pereopods 6–7 dactylus with 2 accessory hooks ....................................................................... 5 —— Pereopods 6–7 dactylus with 1 accessory hook ........................................................................ 7

5 Rostrum short ......................................................... Cerapus murrayae Lowry & Berents, 2005 —— Rostrum long ............................................................................................................................. 6

6 Pereopods 3–4 coxa fused to pereonites ................... Cerapus volucola Lowry & Berents, 2005 —— Pereopods 3–4 coxa not fused to pereonites ............. Cerapus bundegi Lowry & Berents, 2005

7 Antenna 1 very long relative to body length (> 0.9 times body length) ............................................................................................ Cerapus brevirostris sp. nov. —— Antenna 1 less than 0.9 times body length ................................................................................ 8

8 Gnathopod 2, carpus palm straight .................................................. Cerapus dildilgang sp. nov. —— Gnathopod 2, carpus palm deeply excavate .............................................................................. 9

9 Pereopod 7 basis with patch of small setae on posterior margin ........... Cerapus lowryi sp. nov. —— Pereopod 7 basis without patch of small setae on posterior margin .................................................................................................. Cerapus chiltoni sp. nov.