Santaremicaris santaremensis

Santaremicaris santaremensis

( Noodt, 1963) comb. nov.

Figs. 2−8 View Figure 2 View Figure 3 View Figure 5 View Figure 6 View Figure 7 View Figure 8

Type material. M5-6.Slide containing two dissected males and some females.

Other examined material. M2-6; M2-8; M5-5 and undissected male and female picked from an unsorted sample collected by Noodt, at the same type location of S. santaremensis comb.nov. and stored at the DZMB. See material and methods for explanation of the codes .

Type locality. Hyporheic zone of the Amazonas River at Santarém ( Pará , Brazil) ( Noodt, 1963) ( Fig. 1 View Figure 1 ). Approximate coordinates: 02°25’S 54°42’W. Other occurrences. Upper reaches of Negro River , lower reaches of the Tapajós and Tocantins Rivers GoogleMaps .

Description of male ( Figs. 2 View Figure 2 −4). Total length 285 µm (much shorter than measures given by Noodt, 1963, p. 144: 370−380µm), measured from rostrum to end of furca. Rostrum not fused to cephalothorax, with wide base and two sensilla on tip ( Fig. 2A, B View Figure 2 ). Cephalothorax and Urs 3−5 with dorsal integumental window ( Fig. 2A, B View Figure 2 ), absent on Ur2. Pattern of sensilla as depicted( Fig.2A, B View Figure 2 );last Ur with distal frill undulate and thicker than those of previous Urs ( Figs. 2A, B View Figure 2 , 3C View Figure 3 ). Telson smooth ( Fig. 3C View Figure 3 ), with proximal pore on lateral margins, with pair of sensilla adjacent to anal operculum, and without additional ornamentation; Aop slightly concave medially ( Fig. 2A View Figure 2 ); Fu ( Figs. 2A, B View Figure 2 , 3C View Figure 3 ) cylindrical, approximately 2.5 times as long as wide, slightly enlarged distally in lateral view, slightly irregular on outer margin and convex on inner margin in dorsal view; presence of distal outer pore, and two lateral setae on proximal third; seta I longer than seta III, almost as long as setae VI and VII ( Fig. 3C View Figure 3 ); seta II absent; seta IV distally inserted on outer margin, longer than setae I, III, VI and VII; seta V the longest, about four times longer than Fu; dorsal seta (VII) at distal third; all setae smooth except for unipinnate seta IV.

A1 ( Fig. 3A View Figure 3 ): eight-segmented; of the coiled type with segments V to VIII forming functional unit for clasping female; armature as follows: I(0)/ II(6)/ III (4)/ IV (1+1Ms)/ V (4+(1+Ae))/ VI (2+Ms)/ VII (1+Ms)/VIII(7+ acrothec of 2+Ae) .

A2 ( Fig. 3B View Figure 3 ): allobasis without abexopodal armature, with small outer spinule proximally; one-segmented exp with long unipinnate seta; free endopodal segment with two proximal rows of spinules on inner margin, and transverse row of spinules subterminally; presence of two inner marginal spines and five terminal setae/spines, two of them geniculated.

Labrum triangular in lateral view.

Md: Coxal gnathobasis with distal row of teeth and seta; palp one-segmented, with two distal setae.

Mx1: Praecoxal arthrite with five elements (surface seta thick and blunt, three claw-like pinnate spines, and slender seta); coxal endite with one seta; basis with three setae.

Mx: Allobasis with two endites; proximal endite with one seta; distal endite with two smooth setae and serrate spine; proximal endopodal segment drawn out into claw; distal endopodal segment with two setae.

Mxp: subchelate; syncoxa about 1/3 length of basis; enp drawn into spinulose claw.

P1 (Fig. 4A): coxa smooth. Anterior surface of basis with row of spinules on inner margin, distalmost enlarged; rows of spinules near insertion of enp and exp on anterior surface; and outer seta, outer pore and two outer spinules.Enp two-segmented:enp1 nearly as long as exp1 and exp2 combined, with two inner rows, two outer rows and one distal row of spinules (Fig.4A); enp2 with outer spine and long geniculate seta, with posterior hyaline frill. Exp three-segmented: exp1 with outer spine, rows of spinules on outer margin, proximal and distal to outer spine; exp2 unarmed, with row of outer spinules along outer margin; exp3 with outer row of spinules proximally, two outer spines and two geniculate apical setae.

P2 (Fig. 4B): intercoxal sclerite a small unornamented trapezoidal plate, shorter than coxa, concave proximally and distally; with proximal lateral projections. Coxa with anterior row of spinules. Basis without outer seta, with row of spinules on outer margin and outer pore on anterior surface. Enp one-segmented, 0.4 times as long as exp1, with distal seta as long as exp1, the insertion area of it covering almost the whole width of the segment; with strong spinules on outer margin, not reaching the distal 1/3, distal margin unornamented. Exp three-segmented: exp1 with outer row of spinules, hyaline frill distally on inner corner, and outer spine reaching beyond distal edge of exp2; exp2 with distal row of strong spinules only; exp3 with outer distal row of spinules, hyaline frill at inner distal corner, unipinnate distal outer spine, unipinnate distal medial seta and distal inner seta (distal inner seta distally broken).

P3 (Fig. 4C): intercoxal sclerite a small unornamented trapezoidal plate as long as coxa, straight proximally, concave distally, with proximal lateral projections. Coxa rectangular, with diagonal row of spinules on anterior face. Basis long, trapezoidal, bearing long outer seta and outer pore, hook-like spinule on proximal inner corner and row of spinules. Enp lacking. Exp one-segmented, rectangular, long, slightly curved inwards, smooth on outer margin, with long and spatuliform apophysis; thumb longer than apophysis, with medial hump and ending in long tip.

Figure 4. Santaremicaris santaremensis comb. nov., male. P1 (A), P2 (B), P3 (C), P4 (D), and P5 (E).

P4 (Fig. 4D): intercoxal sclerite a small unornamented trapezoidal plate, shorter than coxa, straight proximally, concave distally, with proximal lateral projections. Coxa smooth. Basis not ornamented, with outer pore on anterior surface; outer seta long, reaching beyond distal margin of exp1. Enp triangular, with strongly chitinized areas, short, approximately 0.7 times as long as exp1, smooth and acuminate. Exp three-segmented: exp1 with outer row of spinules in proximal third; rows of spinules proximally and distally to outer spine reaching distal edge of exp2; inner margin with row of spinules from median to distal margin replacing hyaline frill, with additional row of spinules in proximal third; exp2 with distal row of strong spinules; exp3 with distal row of spinules on outer margin, inner hyaline frill at distal corner, unipinnate outer spine, and distal unipinnate seta nearly twice as long as outer seta.

P5 (Fig. 4E): intercoxal sclerite a large triangular plate reaching the proximal 1/3 of the limb, with distomedial claviform cuticular process. P5 consisting of well-developed triangular plate reaching middle of subsequent Ur; proximal 1/3 with irregular inner margin and outer hump, medially with concave inner margin and convex outer margin; distally with convex inner margin and concave outer margin; inner margin bearing row of small spinules; distal portion spiniform; armature consisting of very long outer basal seta and 2 additional setae;

P6 represented by unarmed cuticular flap.

Description of female ( Figs. 5−8 View Figure 5 View Figure 6 View Figure 7 View Figure 8 ). Length 351μm (slightly shorter than measurements given by Noodt, 1963, p. 144: 350−380μm), measured from tip of rostrum to end of furca. Sexual dimorphism expressed in A1, P1, P2, P3, P4, P5 and Gds. Cph and Urs2 (Gds), 3, and 4 with dorsal integumental windows. Urs2−4 with undulate distal frill on dorsal view, Ur4 with undulate distal frill on lateral view. Telson as in male, except for the more concave Aop ( Fig. 5A View Figure 5 ). Fu ( Fig. 5 View Figure 5 A−C) cylindrical, approximately 2.5 times longer than wide, slightly enlarged distally in lateral view, convex on inner margin in dorsal view, concave in the outer margin, with distal outer pore, and two lateral setae at end of proximal third. Fu armature as follows: seta I and III subequal, both about twice shorter than setae IV and VII; seta II absent; seta IV almost as long as setae VI and VII, subterminally inserted on outer margin; seta V the longest, 3.4 times longer than Fu; dorsal seta (VII) at distal third; all setae smooth, except for unipinnate setae IV and VII.

A1 seven-segmented ( Fig. 6A, B View Figure 6 ); armature as follows:I(0)/II(4)/III(4)/IV(1+(1+ae))/V(0)/VI(0)/ VII(7+ (2+ae)).

A2 as in male.

Md ( Fig. 6C View Figure 6 ), Mx1 ( Fig. 6D View Figure 6 ), Mx ( Fig. 6E View Figure 6 ), Mxp ( Fig. 6F View Figure 6 ) as described for male.

P1 ( Fig. 7A View Figure 7 ): intercoxal sclerite a small unornamented trapezoidal plate, shorter than coxa, concave proximally and distally. Coxa as in male; basis with row of spinules on inner margin not as developed as in male, without row of spinules near insertion of enp and exp, and with five outer spinules; exp1−3 as in male; enp1 lacking proximal row of spinules on inner margin, enp2 as in male.

P2 ( Fig. 7B View Figure 7 ): intercoxal sclerite a small unornamented trapezoidal plate, shorter than coxa, slightly concave proximally and distally, with proximal lateral projection. Coxa smooth; basis with row of spinules near insertion of enp, outer pore and outer row of spinules; outer margin of exp1−3 as in male; enp thinner than in male, without outer ornamentation along the proximal 2/3, with subdistal spinules, two on inner margin, one on outer margin, with thin and long distal seta, as long as exp1, the insertion area not as wide as in the male.

P3 ( Fig. 7C View Figure 7 ): intercoxal sclerite a small unornamented trapezoidal plate, shorter than coxa, proximally straight and irregular distally. Coxa smooth; basis with outer pore, row of spinules distal to long outer seta, and row of spinules near insertion of enp; exp two-segmented, exp1 enlarged, with strong spinules in proximal third, proximally and distally to outer spine, distal row of strong spinules and row of small spinules on inner margin; exp2 with subdistal row of spinules on outer margin, with inner hyaline frill, outer bipinnate spine and distal unipinnate seta; enp one-segmented, 0.5 times as long as exp1, unarmed, acuminate distally.

P4 ( Fig. 7D View Figure 7 ): intercoxal sclerite a small unornamented trapezoidal plate, shorter than coxa, almost straight proximally, concave distally, with proximal lateral projection. Coxa smooth; basis with row of spinules distally to outer seta,and row of spinules near enp insertion; exp1 without ornamentation on inner margin and with a distal inner hyaline frill, outer margin with row of spinules in proximal third, proximally and distally to outer spine; exp2−3 as in male; P4 enp one-segmented, slightly longer than exp1 and bearing one distal and bipinnate spine fused to segment; with two spinules on inner margin, medial and anterior spinules inserted at base of spine.

P5( Fig.7 View Figure 7 E−8): well developed, a simple trapezoidal plate; distal margin ending on spiniform process, without inner ornamentation, reaching distal margin of the Gds; armature composed of proximal, long and articulated seta, two medial setae, and distal seta. Intercoxal sclerite a small triangular plate.

P6 ( Fig. 8 View Figure 8 ): unarmed concave plate with median hump covering Gf.