Ancylomenes, Okuno & Bruce, 2010

Okuno, J. & Bruce, A. J., 2010, Designation of Ancylomenes gen. nov., for the ‘ Periclimenes aesopius species group’ (Crustacea: Decapoda: Palaemonidae), with the description of a new species and a checklist of congeneric species *, Zootaxa 2372 (1), pp. 85-105 : 87-88

Key to the species of Ancylomenes gen. nov.

1. Dactyli of ambulatory pereiopods simple..................................................................................................................... 2

– Dactyli of ambulatory pereiopods biunguiculate.......................................................................................................... 3

2. Second pereiopods similar in form ............................................................................ A. tosaensis (Kubo) comb. nov.

– Second pereiopods unequal and dissimilar, major pereiopod with dactylus dorsally with lateral flange ...................... ..................................................................................................................................... A. lucasi (Chace) comb. nov.

3. Carapace with 2-3 postorbital teeth (third abdominal tergum with elevated posterior median carina) ......................... ..................................................................................................................................... A. aesopius (Bate) comb. nov.

– Carapace with 0-1 postorbital teeth .............................................................................................................................. 4

4. Carpus of second pereiopod distinctly longer than chela (carapace without epigastric spine; third abdominal tergum with posterior median carina) .......................................................... A. longicarpus (Bruce & Svoboda) comb. nov.

– Carpus of second pereiopod shorter than chela ............................................................................................................ 5

5. Distolateral margin of proximal segment of antennular peduncle pointed, triangular ................................................. 6

– Distolateral margin of proximal segment of antennular peduncle rounded.................................................................. 7

6. Dactylus of major second pereiopod slender, gradually tapering distally… A. pedersoni (Chace) comb. nov.

– Dactylus of major second pereiopod depressed, dorsally flattened ............................................................................... .......................................................................................... A. anthophilus (Holthuis & Eibl-Eibesfeldt) comb. nov.

7. Ophthalmic somite with interocular process obsolete .................................................................................................. 8

– Ophthalmic somite with interocular process developed ............................................................................................. 11

8. Rostrum armed dorsally with 10–13 teeth.................................................................................................................... 9

– Rostrum armed dorsally with 7–9 teeth...................................................................................................................... 10

9. Dactylus of third pereiopod 7.5 or more times as long as basal width; rostrum armed ventrally with 1 or 2 teeth ....... ............................................................................................................................... A. adularans (Bruce) comb. nov.

– Dactylus of third pereiopod about 5.5 times as long as basal width; rostrum armed ventrally with 3–5 teeth .............. ..................................................................................................................................... A. aqabai (Bruce) comb. nov.

10. Third abdominal tergum posterodorsally subcarinate; scaphocerite narrow, 2.7–3.3 times as long as width................ ........................................................................................................................................... A. luteomaculatus sp. nov.

– Third abdominal tergum posterodorsally not markedly carinate; scaphocerite broad, 1.9–2.4 times as long as width. ............................................................................................................................... A. magnificus (Bruce) comb. nov.

11. Propodi of ambulatory pereiopods with single ventral spine posterior to distoventral spine..................................... 12

– Propodi of ambulatory pereiopods with two or more ventral spines posterior to distoventral spine ......................... 13

12. Second pereiopods overreaching tip of scaphocerite by distal part of meri, cutting borders of fingers with 6–8 acute, recurved teeth............................................................................................................. A. venustus (Bruce) comb. nov.

– Second pereiopods overreaching tip of scaphocerite by proximal part of palm, cutting borders of fingers with 2–4 acute, recurved teeth ................................................................................................ A. sarasvati (Okuno) comb. nov.

13. Rostrum straight, upwardly directed..................................................................... A. tenuirostris (Bruce) comb. nov.

– Rostrum horizontal, usually arched ........................................................................................................................... 14

14. Dactylus of second pereiopod armed proximally with a single tooth; closed fingers of second pereiopod with marginal proximal concavity........................................................................................... A. holthuisi (Bruce) comb. nov.

– Dactylus of second pereiopod armed with 2 or more recurved teeth ......................................................................... 15

15. Fingers of second pereiopod armed with 4 large acute teeth................................. A. grandidens (Bruce) comb. nov.

– Fingers of second pereiopod armed with small recurved teeth .................................................................................. 16

16. Carpus of second pereiopod shorter than palm; third abdominal tergum posterodorsally subcarinate .......................... .......................................................................................................... A. kobayashii (Okuno & Nomura) comb. nov.

– Carpus of second pereiopod as long as, or longer than palm; third abdominal tergum posterodorsally not markedly carinate........................................................................................................................................................................ 17

17. Second pereiopod with carpus distinctly longer than palm; dactyli of ambulatory pereiopods with ungues only slightly longer than accessory teeth ....................................................................... A. speciosus (Okuno) comb. nov.

– Second pereiopod with carpus shorter or not markedly longer than palm; dactyli of ambulatory pereiopods with ungues markedly longer than accessory teeth.......................................................... A. amirantei (Bruce) comb. nov.