Strandesia velhoi Higuti & Martens, 2013

Ferreira, Vitor Góis, Higuti, Janet & Martens, Koen, 2020, Taxonomic revision of Strandesia s. s. (Crustacea, Ostracoda) from four Brazilian floodplains, with the description of three new species, Zootaxa 4760 (1), pp. 1-74 : 34-38

6. Strandesia velhoi Higuti & Martens, 2013

( Figs. 18–20 )

2007 Bradleystrandesia sp. 3—Higuti et al.: 1934, Table 2.

2009 Bradleystrandesia sp. 3—Higuti et al.: 664, Table 1.

2009 Bradleystrandesia gr. obtusata sp. 3—Higuti et al.: 664, Table 1.

2010 Bradleystrandesia sp. 3—Higuti et al.: 267, Table 2.

2010 Bradleystrandesia gr. obtusata sp. 3—Higuti et al.: 267, Table 2.

2013 Strandesia velhoi n. sp. —Higuti et al.: 201, Figs. 7 , 9A .

Type locality and material

Manezinho backwater, an open lake in the Paraná River system, in washed roots of Eichhornia crassipes , collected on 12.01.2011 by JH & KM. Approximate coordinates: 22°46’55”S, 53°20’59”W.

Type material (Holotype) is stored in the Museum of Zoology of the University of São Paulo (MZUSP), no MZUSP 27452. The paratype is stored in the MZUSP, no MZUSP 27457 ( Higuti et al. 2013).

Material examined

One female (MZUSP 40429) was used for soft part illustrations from Manezinho Backwater (22°46’44.9”S, 53°20’56.3”W). Three females (OC.3285, MZUSP 27453, MZUSP 27454) were used for SEM from Aurélio Lake (22°41’36.5”S, 53°13’52”W). All illustrated specimens are from Paraná River floodplain.

Measurements of illustrated specimens (in mm)

L (n=3): 1.167 –1.204, H (n=1): 0.706, W (n=2): 0.648 –0.670.

Diagnosis (after Higuti et al. 2013)

CpLl high and short. CpD with a clear anterior rostrum and a bluntly rounded posterior margin. RV with anterior selvage clearly inwardly displaced. LV with internal groove along ventral margin, with pegs. A2 with natatory setae reaching 3/4 of length of apical claws. CR with ventral margin weakly serrated, its attachment with an oval Triebel’s loop in the main branch.

Abbreviated redescription of female (after Higuti et al. 2013)

LVi ( Fig. 18A ) without inner list on anterior calcified inner lamella; inner lamella wider anteriorly than posteriorly; internal groove long ventral and posterior margin, with pegs distributed along ventral and posterior margins; greatest height situated in front of the middle.

RVi ( Fig.18B ) with anterior selvage clearly inwardly displaced; anterior calcified inner lamella wider than posterior one; greatest height situated in front of the middle.

CpLl ( Fig 18C ) high and short; greatest height situated in front of the middle; both anterior and posterior margins bluntly rounded. CpD ( Fig. 18D ) with greatest width slightly in front of the middle; with anterior rostrum. CpV ( Fig. 18E ) with ventral valve margin of LV very weakly sinuous in the middle; with anterior rostrum. CpFr ( Fig. 18F ) view weakly oblique, with LV being the lower valve.

A1 (not illustrated) with seven segments. First segment with one short subapical seta and two long apical setae; WO not seen. Second segment wider than long, with one short dorsal seta; RO small. Third segment with two setae (the smaller with the length of the fourth segment). Fourth segment with two short and two long setae. Fifth segment with three long and one short setae. Sixth segment with four long setae. Seventh segment with one short and two long setae, and one aesthetasc ya slightly longer than the short seta.

A2 ( Figs. 19 A–B) with protopodite, exopodite and three-segmented endopodite. Protopodite with two ventral setae; and one long ventro-distal seta. Exopodite reduced to a small plate, with one long and two unequal short setae. First endopodal segment with one ventral aesthetasc Y, one long apical seta (reaching the tip of the second endopodal segment) one group of five long and one short swimming setae (the five long setae reaching 3/4 of the length of apical claws; the short one almost reaching the middle of third segment). Second endopodal segment undivided, with two unequal but long dorsal setae and a group of four long ventral t setae; apically with three claws (G1 and G3 equally long, G2 slightly shorter), three setae (z1 long, z2 and z3 short, with ca. 1/2 the length of z1) and a short aesthetasc y2 ( Fig. 19B ). Terminal segment ( Fig. 19B ) with two claws (one long GM; one short, Gm), an aesthetasc y3 with an accompanying seta (seta longer than aesthetasc), fused over a short distance only, and a fine g-seta, the latter shorter than accompanying seta and aesthetasc y3.

First segment of Md palp ( Fig. 19 C—chaetotaxy not completely shown) with short (not reaching beyond tip of ss-seta) and smooth α-seta. Second segment ventrally with long (longer than α-seta), stout and hirsute ss-seta. Penul- timate segment laterally with cone-shaped, distally hirsute γ-seta. Terminal segment ca. 1.5x as long as basal width, slightly tapering. Md coxa (not illustrated) as typical of the family, elongated with an apical row of strong teeth of variable size, interspaced with some small setae.

Mx1 ( Fig. 19 D—chaetotaxy not completely shown) with three masticatory lobes, a two-segmented palp and a large respiratory plate (the latter not illustrated). Basal segment of palp with six long apical setae, and one short subapical seta. Terminal palp segment ca. 2x as long as basal width, slightly curved and tapering, apically with three claws and three setae. Third endite with two large, distally serrated bristles. Lateral seta on third endite reaching the end of the endite. First endite with one sideways-directed bristle.

T1 protopodite ( Fig. 19E ) with two short a-setae; b-seta longer than d-seta. Apically with 10 hirsute setae, subapically with a group of four setae. Endopodite with three unequal long hirsute apical setae (not illustrated).

T2 ( Fig. 19F ) protopodite with with seta d1 relatively long and seta d2 shorter, ca. half of the length of d1. First endopodal segment with one subapical hirsute seta (e). Second endopodal segment medially divided into a- and bsegments; segment “a” with one long apical hirsute seta (f); segment “b” with one shorter seta (g) reaching beyond tip of terminal segment. Third endopodal segment with one apical claw (h2) and two setae (one ventro-apical (h1) with 1/5 the length of h2 and one dorso-apical (h3) slightly longer than h1).

T3 ( Fig. 20 A—chaetotaxy not completely shown) with three segments. First segment with three long setae (d1, d2, dp). Second segment, longer than wide, with one subapical seta (e). Third segment, also longer than wide, with one lateral, hirsute seta (f); distal part of the third segment fused with fourth segment into a modified pincer, with one apical comb-like seta (h2), one small recurved seta, with 1/5 of the length of the comb-like seta, and one longer and distally hirsute seta (h3). Small tooth-like structures present at the base of the comb-like seta (arrowed in Figure 20A ).

CR ( Fig. 20B ) stout and straight, with ventral margin weakly serrated. Proximal claw 2/3 of the length of distal claw. Proximal seta hirsute, ca. 1/3 of length of distal seta.

CR attachment ( Fig. 20C ) stout, with oval-triangular Triebel’s loop in the main branch; vb long and straight; db short and curved.

Male unknown

Differential diagnosis (after Higuti et al. 2013)

This species can be distinguished from the others in this lineage by the large size and the high and short shape of the valves, the presence of the large anterior selvage of the RV and the anterior rostrum, as well as by the absence of a posterior flange on the RV.

Ecology and distribution

Strandesia velhoi was recorded from lentic environments, associated with a variety of macrophytes with different life forms, in Amazon, Araguaia, Pantanal and Paraná floodplains. This species occurred in acidic to basic environments, with pH range of 4.2–9.5. Electrical conductivity and dissolved oxygen ranges were 11–222.5 µS. cm-1 and 0.4–11.8 mg. L-1, respectively (see Table 1). Distribution: Brazil.

Figures

FIGURE 7 Strandesia thomazi nov. sp. A, T2 (MZUSP 40403); B, T3 pincer (MZUSP 40403); C, CR (MZUSP 40403); D, CR attachment (MZUSP 40403). Scale bars, 50 μm.

FIGURE 9 Strandesia galeati nov. sp. A, A1 (MZUSP 40411); B, A2 except last segment (MZUSP 40412); C, A2 last segment (MZUSP 40412); D, Md palp showing α, ss, γ setae (MZUSP 40411); E, Mx1 (MZUSP 40412); F, T1 (MZUSP 40412). Scale bars, 50 μm.

FIGURE 18 Carapace and valves of Strandesia velhoi. A, LVi (OC.3285); B, RVi (OC.3285); C, CpLl (MZUSP 27453); D, CpD (MZUSP 27454); E, CpV (MZUSP 27455); F, CpFr (MZUSP 27454). Scale bars, 200 μm. Reproduced from Higuti et al. (2013) with permission from Brill.

FIGURE 19 Strandesia velhoi. A, A2 except last segment (MZUSP 40429); B, A2 last segment (MZUSP 40429); C, Md palp showing α, ss, γ setae (MZUSP 40429); D, Mx1 (MZUSP 40429); E, T1 (MZUSP 40429); F, T2 (MZUSP 40429). Scale bars, 50 μm.

FIGURE 20 Strandesia velhoi. A, T3 pincer (MZUSP 40429); B, CR (MZUSP 40429); C, CR attachment (MZUSP 40429). Scale bars, 50 μm.