Eirinicaris antonioi gen. et.

Corgosinho, Paulo H. C., Schizas, Nikolaos V., Previattelli, Daniel, Rocha, Carlos E. Falavigna da & Santos-Silva, Edinaldo Nelson dos, 2017, A new genus of Parastenocarididae (Copepoda, Harpacticoida) from the Tocantins River basin (Goias, Brazil), and a phylogenetic analysis of the Parastenocaridinae, Zoosystematics and Evolution 93 (1), pp. 167-187 : 169-174

Eirinicaris antonioi gen. et. sp. n. Figs 2, 3, 4, 5, 6, 7, 8

Type material.

Male dissected holotype mounted onto three slides (sample VEA17/B/R/ROF/musgo; 20 Jan 2012; MZUSP 35273). One dissected female paratype mounted onto one slide (sample VEA17/B/R/ROF/musgo; 20 Jan 2012; MZUSP 35274), one undissected female paratype (sample VEA15/C/CP/50; 20 Dec 2012; MZUSP 35274), and two undissected male paratypes mounted onto a single slide (sample VEA17/B/R/ROF/musgo; 20 January 2012; MZUSP 35274).

Type locality.

National Park of the Chapada dos Veadeiros (North of Goiás, Brazil); Água Fria River; 1230 m MSL; speed of water current from low to medium; temperature 20 ± 5°C; pH 5 ± 1. Coordinates: 14°5 ’30.89” S, 47°29 ’34.47” W.

Etymology.

The generic name is in honour of the first author’s wife, Eirini Grapsa, combining her first name with the ancient Greek substantive for shrimp, καρίς (caris). The specific epithet " antonioi " is posthumous homage to Antonio Alves Corgosinho Filho, father of the first author.

Description of male.

Length 320μm (variability of the type series 314-328μm), measured from rostrum to end of telson excluding furca. Rostrum not fused to cephalothorax, with wide base and two sensilla on tip (Fig. 2A). Cephalothorax and Urs-2-5 with dorsal integumental window (Fig. 2A). Patterns of sensilla as depicted. Telson with transverse row of small spinules dorsally, anterior to sensilla, and with rows of spinules covering most of preopercular lateral margin (Figs 2A, B, C), without ornamentation ventrally (Fig. 2D), posteriorly clefted, conferring a bilobate shape posteriorly (Fig. 6D), with a pore on the ventro-lateral margin. Furca irregular, with inner and outer bulges proximally (Figs 2 B–D and 6 D–F) with distal outer pore (Fig. 6F, arrowed), about three times as long as width, inner and dorsal margins convex, outer and ventral margins concave; with dorsal, inner and outer spinules; with seven setae as follows: setae I, II and III and dorsal seta VII not aligned, separated by wide gap; setae I, II and III displaced anteroventrally; seta I modified into short spine, with broad base and acuminate tip; seta II with broad base, a long peduncle and one distal aesthetasc-like structure, twice as long as seta III, the latter 1/3 as long as furca, with a long peduncle and one distal aesthetasc-like structure; setae IV to VII smooth; seta IV inserted subdistally on outer margin, about as long as telson excluding the furca; seta V inserted distally, twice as long as seta IV; seta VI inserted distally next to seta V, shorter than seta IV; dorsal seta VII inserted in a depression located in the middle of the furca.

A1 (Figs 3A, B; 6A, B) eight-segmented, haplocer, with small process in segment seven (arrowed on Figs 3A, B; 6B); segments 5, 6, and 7 forming a functional unit for clasping the female, in grasping position, segment 7 bent inwards against segment 6, segment 8 points in opposite direction (Fig. 6B); segments armature as follows: 1 (0)/2(5)/3(4)/4(1)/5(3+ (1+ae))/6(0)/7(0)/8(7+ modified seta + (2+ ae)); segment 8 with seven slender setae, two seta fused basally to aesthetasc, and one modified seta, the latter as in Fig. 6C.

A2 (Fig. 2e1) allobasis without abexopodal armature, with small outer spinule proximally; one-segmented exp with one bipinnate seta; free endopodal segment bearing seven setae/spines, outermost strongly developed.

Labrum (not shown) triangular in lateral view.

Md as in Fig. 2e2. Coxal gnathobasis with distal teeth and one seta; palp one-segmented, with two distal setae.

Mx1 as in Fig. 2e3. Praecoxal arthrite with five elements (one surface seta, three claw-like pinnate spines, and one slender seta); coxal endite with one, basis with three setae.

Mx as in Fig. 2e4. Allobasis with two endites; proximal endite with one, distal endite with two elements, one of them transformed into serrated spine; proximal endopodal segment drawn out into claw, distal endopodal segment with two setae.

Mxp (Fig. 2e5) subchelate; syncoxa about 1/3 the length of basis; enp drawn into spinulose claw.

P1 (Figs 3B, 7A). Unarmed coxa ornamented with posterior row of spinules; inner seta of basis reaching tip of enp-1, with small row of spinules near insertion of enp, with comparatively smaller outer seta, with pore and row of spinules beneath outer seta; enp two-segmented, enp-1 nearly as long as exp-1 and exp-2 combined, with inner row of spinules (Fig. 7A), and two outer rows of spinules; enp-2 with one outer spine and one long geniculate seta, with posterior hyaline frill; exp three-segmented, exp-1 with outer spine, proximal and distal rows of spinules on outer margin, proximal and distal to outer spine, exp-2 unarmed, with row of inner spinules close to distal corner, exp-3 with outer row of spinules proximally, with two outer spines and two geniculate apical setae.

P2 (Figs 3C, 7 A–B) coxa ornamented with posterior spinules; basis without outer seta, with row of spinules on outer margin and one outer pore; enp one-segmented, reaching middle of exp-1, armed with one distal seta, ornamented with one distal and two outer spinules; exp three-segmented, exp-1 with long outer spine, ornamented with medial row of outer spinules, with one long spinule and smaller spinule close to outer spine (Figs 3C, 7B), with hyaline inner frill; exp-2 unarmed, with distal row of spinules; exp-3 with one outer unipinnate spine, one distal unipinnate spine twice as long as outer element, and one bipinnate apical seta nearly twice as long as previous element, additionally with longitudinal row of spinules on distal third, proximal to outer spine and inner hyaline frill.

P3 as in Figs 3D, d1, d2 and 7B-C. Coxa quadratic, with posterior row of spinules; basis short, quadratic, with outer pore, with row of strong spinules close to exp; enp modified as claviform aesthetasc-like seta (Figs 3D, 7 B–C); exp unisegmented, rectangular, about four times as long as wide, inner margin irregular, with one medial inner hump, outer margin straight, with unevenly distributed spinules, distal margin flat, inner apophysis shorter than exp, blade-shaped, without distal spine or seta, completely fused to exp, thumb slightly longer than apophysis, blade-shape, with broad base, curved inwards proximally.

P 4 as in Figs 3E, 7B. Coxa with posterior row of spinules; basis with outer pore, outer seta, and row of outer spinules close to exp; enp cylindrical, with accuminate tip, approximately half the length of exp-1, with three distal spinules and one medial outer spinule; exp 3-segmented, exp-1 with long outer spine, ornamented with row of spinules proximally and subdistally, with comparatively smaller distal spinules, and inner hyaline frill; exp-2 un armed, with distal row of spinules (a long one on outer edge; arrowed), exp-3 with row of outer spinules subdistally, with one unipinnate outer spine, and one bipinnate distal seta nearly twice as long as outer element.

P5 (Figs 3F, 7 D–E) well developed reaching slightly beyond middle of second urosomite; simple triangular plate with outer pore, distal inner margin a long and pointed, outwardly curved, spinous process with distal pore (arrowed on Figs 3F and 7D), without inner ornamentation; armature consisting of very long outer basal seta and two shorter elements, of which proximal one shortest.

P6 (Fig. 7E), large tetra-lobbed fused plate covering genital area.

Description of female.

Length 310μm (variability of the type series 310-326μm), measured from tip of rostrum to end of telson, excluding furca. Sexual dimorphism ex pressed in A1, P1, P3, P4, genital-double somite, number of integumental windows, telson and furca. Cephalothorax and Urs-2-4 with dorsal integumental windows; window on Urs-4 extending into ventral area (Figs 5B, 8A-B). Telson smooth, and small ventral tube pore near insertion of furca (Fig. 8A, arrowed); anal operculum smooth and convex (Figs 4H, 8B). Furca (Figs 4H-I, 5B, 8A-B) rectangular, with distal ventral pore (Fig. 8A, arrowed), three times as long as wide, smooth, slightly tapering distally, with seven smooth setae as follows: setae I, II and III, and dorsal seta VII inserted medially, aligned, the former three setae more or less opposite to the latter; lateral setae reduced to one small (seta I) and two tiny setae (seta II and III); with two uncinate processes anterior to insertion of dorsal seta (Fig. 4H, arrowed), setae IV, V and VI inserted distally, length and ornamentation of setae IV, V, VI, and VII as in male.

A 1 seven-segmented (Figs 4A, 5B); armature as follows: 1(0)/2(4)/3(4)/4(2+ (1+ae))/5(1)/6(1)/7(7+ (2+ae)).

P1 (Fig. 4B) as in male, with comparatively shorter inner basal seta.

P2 enp (Fig. 4C), slightly dimorphic in ornamentation, with three outer and 2 distal spinules; exp three-segmented, exp-1 without long outer spinule close to the insertion of the outer spine.

P3 as in Figs 4D, 7F. Coxa with posterior row of spinules; basis with outer pore and row of spinules close to outer seta, the latter long; exp two-segmented, exp-1 with proximal row of spinules, outer spine, row of spinules around outer spine, and inner hyaline frill; exp-2 with subdistal row of outer spinules, with inner hyaline frill, outer unipinnate spine and distal bipinnate element; enp one-segmented, spiniform, with one outer spinule as shown, ⅔ the length of exp-1.

P4 (Figs 4E, 7F) coxa and basis as in male; exp-1and 3 as in male, enp-2 without long spinule on outer edge; enp (Fig. 4E) spiniform, about as long as exp-1, distally bipinnate.

P5 (Figs 4F, 5B, 7F) well developed, a simple triangular plate; distal margin a long and pointed, outwardly curved, spinous process with distal pore (Fig. 7F, arrowed), without inner ornamentation, reaching beyond genital field; armature as in male.

P6 (Figs 4G, 7F) represented by naked opercular plate much broader than height covering genital opening.