Microdeutopus, A. Costa, 1853

Myers, Alan, Plaiti, Wanda & Rousou, Maria, 2018, A new species of Microdeutopus, M. periergos sp. nov. (Crustacea, Amphipoda, Senticaudata, Aoridae) from Cyprus (East Mediterranean Sea), Zootaxa 4378 (1), pp. 144-150 : 149-150

Key to World species of Microdeutopus (males only)

1. Gnathopod 1 carpus with posterodistal margin produced into 2 or more spines..................................... 2

- Gnathopod 1 carpus with posterodistal margin produced into a single spine........................................ 8

2. Gnathopod 1 carpus with outer of two spines the longer....................................................... 3

- Gnathopod 1 carpus not as above......................................................................... 5

3. Gnathopod 1 carpus with very long setae on the distal margin.............................. M. sporadhi Myers, 1969b

- Gnathopod 1 carpus lacking very long setae on the distal margin................................................ 4

4. Gnathopod 1 carpus with primary spine slender, secondary spine not arising from margin of primary spine........................................................................................... M. chelifer ( Spence Bate, 1862)

- Gnathopod 1 carpus with primary spine broad based, secondary spine arising from anterior margin of primary spine............................................................................................... M. similis Myers

5. Gnathopod 1 carpus with central of three spines the longest............................. M. stationis Della Valle, 1893

- Gnathopod 1 carpus with inner of two or more spines the longest................................................ 6

6. Gnathopod 2 basis with anterior margin strongly convex and crenulate...................... M. gryllotalpa Costa, 1853

- Gnathopod 2 basis not as above.......................................................................... 7

7. Gnathopod 1 carpus with outer of two spines arising from posterior margin...................... M. bifidus Myers, 1977

- Gnathopod 1 carpus with outer of two spines arising lateral to the posterior margin............ M. anomalus ( Rathke, 1843)

8. Gnathopod 2 propodus with spine at posterior distal corner..................................................... 9

- Gnathopod 2 propodus without spine at posterior distal corner................................................. 10

9. Gnathopod 2 carpus and propodus subequal in length and breadth......................... M. armatus Chevreux, 1887

- Gnathopod 2 carpus longer and more slender than propodus........................... M. chelifer ( Spence Bate, 1862)

10. Gnathopod 2 very elongate and slender with long pectinate setae on anterior margin of carpus and propodus...................................................................................... M. versiculatus ( Spence Bate, 1856)

- Gnathopod 2 not as above.............................................................................. 11

11. Gnathopod 1 coxa irregularly rounded, not produced anteriorly............................. M. obtusatus Myers, 1973

- Gnathopod 1 coxa strongly produced anteriorly, acute or subacute.............................................. 12

12. Gnathopod 1 carpus with posterodistal margin produced into a slender spine, dactylus slender... M. anomalus ( Rathke, 1843)

- Gnathopod 1 carpus with posterodistal margin produced into a stout triangular spine, dactylus stout................... 13

13. Gnathopod 1 coxa anteriorly produced into a slender spine. Gnathopod 2 basis weakly expanded, carpus and propodus short and stout..................................................................... M. algicola Della Valle, 1893

- Gnathopod 1 coxa only moderately produced anteriorly, subacute. Gnathopod 1 basis strongly expanded, carpus and propodus slender, elongate...................................................................... M. periergos sp. nov.