Strandesia variegata ( Sars, 1901 ) G.W. Müller 1912

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 : 53-57

publication ID	https://doi.org/ 10.11646/zootaxa.4760.1.1
publication LSID	lsid:zoobank.org:pub:ECFD8B11-C217-4456-A6E0-7255F6E1515F
DOI	https://doi.org/10.5281/zenodo.3809776
persistent identifier	https://treatment.plazi.org/id/03980314-C251-0D21-FF61-FCDD08F564AF
treatment provided by	Plazi
scientific name	Strandesia variegata ( Sars, 1901 ) G.W. Müller 1912
status

Treatment

10. Strandesia variegata ( Sars, 1901) G.W. Müller 1912 View in CoL

( Figs. 30–32 View FIGURE 30 View FIGURE 31 View FIGURE 32 )

1901 Neocypris variegata n. sp. — Sars: 33, Plate VII, Figs. 14–16 View FIGURE 14 View FIGURE 15 View FIGURE 16 .

1912 Strandesia variegata ( Sars, 1901) View in CoL —G.W. Müller, 1912: 189.

Type locality and material

São Paulo, São Paulo State, Brazil. This species was described based on specimens hatched from mud by Sars (1901). Type material: lectotype nr F19405a1/ 2 in the Natural History Museum , Oslo, Norway .

Material examined

One female ( MZUSP 40439), used for soft part illustrations, and two females ( MZUSP 40440, MZUSP 40441), used for SEM, were from Maria Luiza Lake (22°40’29.4”S, 53°13’5.8”W). Two females ( MZUSP 40442, MZUSP 40443) from Aurélio Lake (22º41’37.7’’S, 53º13’54.3’’W) were used for SEM. All illustrated specimens are from the Paraná River floodplain.

Measurements of illustrated specimens (in mm)

L (n=2): 1.329 –1.372, H (n=1): 0.670, W (n=1): 0.677.

Diagnosis

Cp subovate, with posterior margin more broadly rounded than anterior margin; RV without anterior selvage and postero-dorsal flange. LV with inner groove along ventral margin. A2 with natatory setae reaching beyond the tips of the apical claws. CR with ventral margin serrated, its attachment with a narrow oval-triangular Triebel’s loop, situated in the main branch.

Abbreviated redescription of female

LVi ( Fig. 30A View FIGURE 30 ) subovate and with broadly rounded margins; with inner groove along ventral margin; with greatest height situated behind the middle, making the posterior section broader than the anterior part; with calcified inner lamella wide along anterior margin, narrow along ventral and posterior margins.

RVi ( Fig. 30B View FIGURE 30 ) subovate; with greatest height behind the middle, with calcified inner lamella as in the LV; without anterior selvage and postero-dorsal flange.

CpRl ( Fig. 30C View FIGURE 30 ) subovate; with greatest height situated behind the middle; posterior region broader than anterior. CpD ( Fig. 30D View FIGURE 30 ) subovate; both extremities broadly rounded. CpV ( Fig. 30E View FIGURE 30 ) subovate; with both extremities broadly rounded, no flaplike overlap of LV by RV.

A1 (not illustrated) with seven segments. First segment with one short subapical and two long apical setae; WO not seen. Second segment wider than long, with one short dorsal seta and a small ventral RO. Third segment with two setae (the smaller one 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 short aesthetasc ya, the latter slightly longer than the short seta.

A2 ( Fig. 31A, B View FIGURE 31 ) with protopodite, exopodite and three-segmented endopodite. Protopodite with two ventral setae; and one long distal seta, the latter passing the middle of the second endopodal segment. 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 beyond the tip of the last endopodal segment), one group of five long and one short swimming setae (the five long setae reaching beyond tips of apical claws; the short one almost reaching 1/4 the length of second endopodal segment). Second endopodal segment undivided, with two unequal dorsal setae and a group of four long ventral t setae; apically with three claws (G1 longest, G2 slightly shorter than G1 and G3; G3 slightly shorter than G1), three setae (z1 and z3 equally long and z2 slightly shorter than both) and a short apical aesthetasc y2 ( Fig. 31B View FIGURE 31 ). Terminal segment ( Fig. 31B View FIGURE 31 ) 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 of aesthetasc y3, but slightly longer than the aesthetasc y3 itself.

First segment of Md palp ( Fig. 31 View FIGURE 31 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. 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. 31 View FIGURE 31 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 elongated, ca. 1.5x as long as basal width, slightly curved and tapering, apically with three claws and three setae. Third endite with two large, serrated bristles; lateral seta on third endite, reaching beyond the end of the endite. First endite with one sideways-directed bristle only, and two equally long basal setae.

T 1 protopodite ( Fig. 31E View FIGURE 31 ) with two short, unequal a-setae, b-seta slightly shorter than d-seta, both hirsute. Apically with 10 hirsute setae, subapically with a group of four such setae. Endopodite with three unequal long hirsute apical setae (not illustrated).

T 2 ( Fig. 31F View FIGURE 31 ) protopodite with seta d1 relatively long and seta d2 shorter, ca. 3/4 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 last segment. Third endopodal segment with one apical claw (h2) and two setae (one ventro-apical (h1) with 1/6 the length of h2 and one dorso-apical (h3) slightly shorter than h1).

T 3 ( Fig. 32 View FIGURE 32 A—chaetotaxy not completely shown) with three segments. First segment with three long setae (d1, d2, dp). Second segment, longer than wide, with three subapical seta (e). Third segment, also longer than wide, with three lateral, hirsute seta (f); distal part of the third segment fused with fourth segment into a modified pincer, with apical comb-like seta (h2), small recurved setae, 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 32A View FIGURE 32 ).

CR ( Fig. 32B View FIGURE 32 ) slender and curved, with ventral margin serrated. Proximal claw 2/3 of the length of distal claw. Proximal seta smooth, ca. 1/5 of length of distal seta.

CR attachment ( Fig. 32C View FIGURE 32 ) stout, with Triebel’s loop oval-triangular, situated in the main branch; vb long and straight; db short and curved.

Male unknown

Differential diagnosis

Strandesia variegata is similar to Strandesia mutica , but it has a broader posterior region in lateral and dorsal view.

Ecology and distribution

Strandesia variegata was recorded from lentic and lotic environments, associated with a variety of macrophytes, with different life forms, in the Pantanal and Paraná floodplains. This species occurred in acidic to neutral environments, with pH range of 4.2–7.4. Electrical conductivity and dissolved oxygen ranges were 11–84.8 µS. cm-1 and 0.2–8.3 mg. L-1, respectively (see Table 1). Distribution: Brazil, Paraguay and West Indies.