Eucyclops festivus Lindberg 1955
Creators: name: Mercado-Salas, Nancy F.
name: Suárez-Morales, Eduardo
name: Silva-Briano, Marcelo
Publisher: name: Zenodo
Year: 2015
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Hexanauplia
Cyclopoida
Cyclopidae
Eucyclops
Eucyclops festivus

description: Eucyclops festivus Lindberg, 1955
(Figures 14 – 21)
Description
Female. Habitus as in Figure 16A. Average body length excluding caudal setae = 866 µm. Body surface (including caudal rami) ornamented with small pits. Prosome representing 59% of total body length. Prosomal fringes serrate dorsally. Urosomal fringes strongly serrate. Genital double somite symmetrical (Figure 16B), representing 10.8% of total body length; proximal third of genital double somite slightly expanded laterally. Seminal receptacle with rounded lateral arms on posterior margin, typical of the serrulatus -complex. Length/width of caudal rami = 4.6; inner margin of caudal ramus smooth; outer margin with strong spinules covering 61% with respect to the total length of ramus. Dorsal seta (VII) 0.5 times as long as caudal ramus and 0.6 times as long as outermost caudal seta (III). Ratio of innermost caudal seta (VI)/outermost caudal seta (III) = 1.0. Lateral caudal seta (II) inserted at 74% of caudal ramus.
Antennule (Figures 14B, 16E–F, 17A). Tip reaching second pediger, antennules ornamented with pits. Armature per segment as follows: 1(8s), 2(4s), 3(2s), 4(6s), 5(4s), 6(1s+1sp), 7(2s), 8(3s), 9(2s+1ae), 10(2s), 11(3s), 12(7s+1ae). Transverse rows of spinules on first segment not observed. Spine on sixth segment reaching midlength of seventh antennular segment.
Antenna (Figures 14C–D, 17B–D). Coxa (unarmed), basis (2s+Exp), plus threesegmented Enp (1s, 9s, 7s, respectively). Basis with rows of spinules on frontal surface:
N1(V), N2(3), N3(5), N4(5), N5(8), N6(10), N15(4), N17 (12), N18(3) and on caudal surface: N7(4), N8(5), N9 + 10(8), N11(4), N12(6), N13(5), N14(8), N16(5), N22(10). Caudal surface of first Enp with B2 (5).
Leg 1 (Figures 15A–B, 17F). Frontal surface of intercoxal sclerite with row I armed with hair-like elements arranged in semicircular pattern, caudal surface with rows I and II bearing minute spinules. Inner coxal seta biserially setulated, caudal coxal surface with spinule formula = A-B-C. Inner basal seta (basipodal spine) reaching middle margin of
Enp3, 0.8 times as long as Enp. Length/width ratio Enp3 = 1.4, apical spine of Enp3 being 1.2 times as long as Enp3.
Leg 2 (Figures 15C–D, 18A–B). Frontal surface of intercoxal sclerite with row I bearing hair-like elements arranged in a circular pattern; caudal surface with row I discontinuous, bearing 7 – 9 small spinules on each side, row II continuous with 24 – 30 small spinules. Distal margin of intercoxal sclerite with two rounded, chitinised projections. Inner coxal seta biserially setulated, caudal coxal surface with spinule formula A-B-C-D.
Length/width ratio of Enp3 = 2, apical spine of Enp3 1.2 times as long as Enp3. No modified setae present.
Leg 3 (Figures 15E–F, 18C–D). Frontal surface of intercoxal sclerite armed with group of long hairs on each side; caudal surface with row I bearing long hairs and with a small gap in the middle, row II continuous bearing 30 – 32 small spinules and row III continuous bearing 32 – 37 spinules. Distal margin with two rounded, chitinised projections. Coxa with strong, biserially setulated inner coxal seta, basally with long hairs and distally with
strong spinules along both margins. Caudal coxal surface with spinule formula = A-B-C. Length/width ratio of Enp3 = 1.9, apical spine of Enp3 as long as segment (Enp3). No modified setae present.
Leg 4 (Figures 15G–H, 18F, 19A). Distal margin of intercoxal sclerite with two low, rounded, chitinised projections. Frontal surface of sclerite with row I bearing long slender spinules arranged in a semicircular pattern on both sides of surface. Caudal surface of intercoxal sclerite with row I with seven strong spinules on each side and with a small gap in the middle margin; row II continuous, with strong spinules, outer margins bearing more spinules than medial margin; and row III divided into three sections, two on outer margins with strong and long spinules and medial margin with 3 – 4 long spinules. Frontal surface of coxa with row of small spinules at insertion of Bsp. Inner coxal spine with heterogeneous ornamentation; inner margin with long hairs on proximal section and strong spinules distally; outer edge with one distal spinule and proximal hair-like elements, gap in the middle margin. Length/width ratio Enp3 = 2.5, length ratio inner spine of Enp3/length Enp3 = 1.2; length ratio outer spine of Enp3/ length Enp3 = 0.9; proportion inner/outer spines Enp3 = 1.3. Lateral seta of Enp3 inserted at 68% of segment. No modified setae in Enp and Exp.
Leg 5 (Figure 19B). Free segment subrectangular, 2.1 times longer than wide, bearing one strong inner spine and two setae; medial seta 1.8 times longer than outer seta and 1.6 times longer than inner spine. Inner spine twice longer than segment.
Remarks. As mentioned by Gutiérrez-Aguirre et al. (2013), E. festivus has been recorded in north and central Mexico and recently also from a pond in the state of Chiapas in southeast Mexico. This species appears to be related to E. estherae sp. nov. and E. wixarica sp. nov., both described herein. Differences among these species are presented in the remarks sections of E. wixarica sp. nov. and E. estherae sp. nov.
description: Published as part of Mercado-Salas, Nancy F., Suárez-Morales, Eduardo & Silva-Briano, Marcelo, 2015, Taxonomic revision of the Mexican Eucyclops (Copepoda: Cyclopoida) with comments on the biogeography of the genus, pp. 25-147 in Journal of Natural History 50 on pages 50-59, DOI: 10.1080/00222933.2015.1061715, http://zenodo.org/record/3983088