A Phylogenetic Analysis of Ilyocryptus Sars, 1862 (Cladocera: Ilyocryptidae) (original) (raw)

2009, International Review of Hydrobiology

revised the taxonomy of the genus Ilyocryptus SARS, 1862 (Branchiopoda: Anomopoda: Ilyocryptidae) and concluded that 28 species can be recognized as valid for the world fauna. In order to test phylogenetic relationships between the species and to contribute to a better understanding of the genus, a cladistic (using branch-and-bound search) analysis was conducted for 25 Ilyocryptus species (two of them with two subspecies). In total, 32 morphological characters were used. An evolutionary-morphological interpretation of the results was also made. Phylogenetic analysis revealed that Ilyocryptus elegans is an earlier derived member of the genus, while other species are separated into two main branches: agilis-and sordidus-lines (without reference to type of moulting). Species with incomplete moulting and species with complete moulting do not form separate clusters, suggesting an independent origin of incomplete moulting within different species groups. 1. Size: very small, maximum length less than 0.6 mm [a = 0; p = 1]. 2. Type of moulting: incomplete [a = 0; p = 1]. 3. Body shape [relatively low, ovoid-elongated = 0; high, triangular-ovoid = 1]. 4. Body remarkably compressed laterally [a = 0; p = 1]. 5. Head shield: a lateral projection near mandibular articulation [a = 0; p = 1]. 6. Mandibular articulation wide, massive [a = 0; p = 1]. 7. Lateral horn on valve [a = 0; p = 1]. 8. Marginal setae in anterior bunch very long [a = 0; p = 1]. 9. Setae at postero-ventral region of valve especially long [a = 0, p = 1]. 10. Setules on setae of posterior valve margin [not modified = 0; with numerous spine-like setules = 1; with only a single spine-like setule on slightly expanded base of seta = 2; a single, robust spine-like setule on markedly expanded base of seta = 3]. 11. Postabdomen: anus distal [a = 0, p = 1]. 12. Preanal teeth appearance [exclusively single = 0; partly doubled = 1; clustered and greatly reduced in size = 2]. 13. Shape of preanal teeth [straight, non-modified = 0; small, uniform, regularly curved = 1; greatly increasing in size in basal direction = 2; markedly reduced in size = 3]. 14. Number of preanal teeth [medium, 7-10 = 0; larger, more than 12 = 1; smaller, not more than 6 = 2]. 15. Additional setules or denticles near preanal teeth [p = 0; a = 1]. 16. Position of basalmost lateral seta [on postanal margin = 0; on anal or preanal margin = 1]. 17. Large gap between basalmost seta and anus [a = 0; p = 1]. 18. Length of lateral setae on postabdomen [markedly longer than paired spines = 0; subequal in size with the spines = 1; markedly shorter than the spines = 2]. 19. Setules on ventral surface of claw base: long [a = 0, p = 1]. 20. Spines on claw base: basalmost markedly shorter and thinner than distalmost [a = 0; p = 1]. 21. Antenna I [long = 0; shortened, without ridges = 1; shortened with denticles and ridges = 2]. 22. Finger-like projection on proximal segment of antenna I: markedly or completely reduced [a = 0, p = 1]. 23. Rows of denticles on distal segment of antenna I [p = 0; a = 1]. 24. Apical swimming setae of antenna II: shortened, less than 0.5 body length [a = 0; p = 1]. 25. Proximal segments of lateral swimming setae with long and rare setules [a = 0; p = 1]. 26. Second seta on outer distal lobe of limb I [p = 0; a = 1]. 27. Limb I: gnathobase [p = 0; a = 1]. 28. A large, bisegmented seta near ejector hooks of limb I [p = 0; a = 1]. 29. Single ejector hook on limb I [a = 0; p = 1]. 30. Limb VI with six bunches of 2-4 robust setules [a = 0, p = 1]. 31. Male body more compressed than female body [a = 0, p = 1]. 32. Aesthetascs on male antenna I with three long and seven short aesthetascs [a = 0, p = 1]. A. A. KOTOV and M. ELÍAS-GUTIÉRREZ