Santaremicaris amazonensis, Santos-Silva, 2021

Santaremicaris amazonensis View in CoL sp. nov.

ZooBank: urn:lsid:zoobank.org:act:976B796E-DE41-494F-BC5D-21BCD727878B Figs. 9 View Figure 9 , 10

Type material. Only one intact male and one dissected male of S. amazonensis sp. nov. present in the slide M2-6 are designated as the syntypes. The dissected male of S. santaremensis comb. nov., the intact and the dissected female of S. santaremensis comb. nov., and the juvenile mounted in the same slide are not part of the type series.

Other examined material. Undissected male picked from an unsorted sample collected by Noodt, at the same type location of P. 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) ( Fig. 1 View Figure 1 ). Approximate coordinates: 02°25’S 54°42’W GoogleMaps .

Etymology. The specific name refers to the

Amazonian biome in which the new species was found.

Description of male ( Figs. 9 View Figure 9 , 10). Length 351µm, measured from rostrum to end of furca. Rostrum not fused to cephalothorax, with wide base and two sensilla on tip ( Fig. 9A, B View Figure 9 ). Cephalothorax and Urs3−5 with dorsal integumental window ( Fig. 9A, B View Figure 9 ), last Ur with undulate distal frill. Patterns of sensilla as depicted ( Fig. 9A, B View Figure 9 ). Telson with pair of sensilla adjacent to anal operculum, without additional ornamentation and with proximal lateral pore. Fu cylindrical ( Fig. 9 View Figure 9 A−C), about 2.5 times as long as wide, slightly enlarged distally in lateral view, slightly irregular on outer margin and slightly convex on inner margin in dorsal view, with distal outer pore, and two lateral setae in proximal third. Armature of Fu as follows ( Fig. 9 View Figure 9 A−C): seta I shorter than seta III, seta II absent, seta III shorter than seta IV; seta IV inserted distally on outer margin, almost as long as seta VII, dorsal seta VII inserted at distal third, longer than seta VI; seta V the longest, more than 3 times longer than furca; all setae smooth.

A1 and A2 as in S. santaremensis comb. nov.

Labrum triangular in lateral view. Md, Mx1, Mx2 and Mxp as described for S. santaremensis comb. nov.

P1 (Fig. 10A): intercoxal sclerite a small unornamented trapezoidal plate, shorter than coxa, straight proximally, concave distally, with proximal lateral projection. Coxa smooth. Basis with row of strong spinules on inner margin, row of minute spinules near insertion of enp and distal to outer seta. Enp two-segmented: enp1 longer than exp1 and exp2 combined, with one inner row, two outer rows and one terminal row of spinules; enp2 with outer spine, long geniculate seta, and posterior hyaline frill. Exp three-segmented: exp1 bearing outer spine, proximal and distal rows of spinules on outer margin; exp2 unarmed, with row of outer spinules; exp3 with outer row of spinules proximally, two outer spines and two geniculate apical setae.

P2 (Fig. 10B): as in S. santaremensis comb. nov., except for presence of spinules on anterior surface of basis, near enp insertion, and stronger spinules on outer margin of enp.

P3 (Fig.10C): Coxa quadratic. Basis rectangular, with long outer seta, outer pore, and V-shaped row of spinules on inner margin. Enp lacking. Exp unisegmented, irregular in shape, long, slightly curved inwards, with cuticular humps on medial and proximal inner margin, inner tube pore near articulation with basis, and with two proximal outer spinules; apophysis long, sigmoid, narrowing in long tip with distal hyaline cushion; thumb shorter than apophysis, with long tip and hyaline inner margin.

P4 (Fig. 10D): similar to S. santaremensis comb. nov., except for presence of row of spinules on outer margin of enp; stronger proximal row of spinules on exp1 inner margin, and weaker distal row of spinules on exp1 inner margin.

P5 (Fig.10E): intercoxal sclerite a large trapezoidal plate reaching the proximal 1/3 of the limb, with distomedial linguiform cuticular process. P5 consisting of well-developed triangular plate reaching middle of subsequent Ur; with irregular outer margin, slightly bulging proximally; inner margin almost straight, with row of small spinules; distal portion ending in strong and thin spiniform process; armature consisting of very long outer basal seta and two additional setae inserted on distalmost hump. P6 represented by unarmed cuticular flap.

Figure 10. Santaremicaris amazonensis sp. nov., male. P1 (A), P2 (B), P3 (C), P4 (D), and P5 (E).