Eucyclops

Suárez-Morales, E., 2004, A new species of Eucyclops Claus (Copepoda: Cyclopoida) from Southeast Mexico with a key for the identification of the species recorded in Mexico, Zootaxa 617, pp. 1-18 : 15-16

Key for the identification of the species of Eucyclops recorded in Mexico

(see also Reid, 1985 for additional characters)

1A. Caudal rami clearly elongate, between 5–8 times longer than wide .................... 2

1B. Caudal rami 5 times or usually less than 5 times longer than wide....................... 3

2A. Caudal rami more than 6 times longer than wide. Antennular membrane not coarsely serrated E. solitarius (= E. cf. solitarius in Grimaldo­Ortega et al. 1998).

2B. Caudal rami between 5 and 6 times longer than wide. Antennular membrane coarsely serrate ....................................................................................... E. festivus

3A. Caudal rami around 5 (usually 4.5) times longer than wide, third exopodal segment of fourth leg 3 times or more longer than it is wide ........................... E. agilis

3B. Caudal rami less than 5 times (normally 3–4) longer than wide, third exopodal segment of fourth leg less than 3 times longer than it is wide ............................... 4

4A. Distal segment of exopod of third leg with normal setae, anal somite not particularly short, more than 0.5 times the length of caudal ramus .................................. 5

4B. Distal segment of exopod of third leg with sclerotized, blunt subdistal setae, anal somite relatively short, 0.35 times the length of caudal ramus ........... E. conrowae

5A. Fifth leg with outer seta shorter than inner spiniform seta (except Mexican specimens of E. pseudoensifer ) ( Grimaldo­Ortega et al. 1998, fig. 32) ....................... 6

5B. Fifth leg with outer seta as long as or clearly longer (more than 1.4 times) than inner spiniform seta .............................................................................................. 7

6A. Fifth leg with ratio of length of inner spine/outer seta= 1.5, caudal rami 4 times longer than wide, 85 % of spinule coverage on outer margin of caudal rami (92% in Mexican specimens of E. cf. prionophorus, Grimaldo­Ortega et al. 1998 ) ........ ...................................................................................................... E. prionophorus

6B. Fifth leg with ratio of length of inner spine/outer seta= 0.6, caudal rami less than 4 times longer than wide, 78 % of spinule coverage on outer margin of caudal rami (58 % in Mexican specimens, Grimaldo­Ortega et al. 1998, fig. 33). The Mexican specimens could represent an undescribed taxon ........................ E. pseudoensifer

7A. Caudal rami with spinules covering more than 70% of the outer margin; dorsal seta between 0.6 and 0.7 times as long as caudal rami. Inner/outer spines of

endopodal segment 3 of fourth legs between 1.6–2.0. Fifth leg inner spiniform seta not particularly slender ......................................................................... E. bondi from the Yucatan Peninsula ( Suárez­Morales et al. 1996) and Florida ( Reid 1992), and E. cf. bondi from Costa Rica ( Collado et al. 1984). In the specimens from central Mexico ( Grimaldo­Ortega et al. 1998), the caudal rami is as in other forms of E. bondi , but its dorsal seta is very short (0.45–0.5 times as long as caudal rami); the outer seta of the fifth leg is shorter than in other forms of E. bondi . The material from central Mexico could represent an undescribed taxon. 7B. Caudal rami with other characters, a variable coverage of spinules, fifth leg with slender inner spiniform seta ................................................................................... 8

8A. Inner spiniform seta of fifth legs about half the length of outer seta, caudal rami 3.2–3.6 times longer than wide; ratio of inner/outer terminal spines of third endopod of fourth leg=1.6 (in Reid 1985), 1.7 (in Collado et al. 1984). E. leptacanthus

8B. Inner spiniform seta of fifth legs about as long as outer seta, caudal rami around 4 (3.8–4.1) times longer than wide; ratio of inner/outer terminal spines of third endopod of fourth leg between 1.1–1.5 ................................................................. 9

9A. Fifth leg inner spiniform seta and outer seta inserted at same level of segment. Dorsal seta/ caudal ramus length ratio= 0.85, inner spiniform seta/outer seta of the fifth legs=0.8.................................................................................... E. torresphilipi

9B. Fifth leg inner spiniform seta and outer seta inserted at different level of the segment. Dorsal seta/ caudal ramus length ratio= 0.6, inner spiniform seta/outer seta of the fifth legs=1.1............................................................................ E. delachauxi