Brasilodopsis amazonica, Almeida & Higuti & Ferreira & Martens, 2021

Almeida, Nadiny Martins de, Higuti, Janet, Ferreira, Vitor Góis & Martens, Koen, 2021, A new tribe, two new genera and three new species of Cypridopsinae (Crustacea, Ostracoda, Cyprididae) from Brazil, European Journal of Taxonomy 762, pp. 1-48 : 24-35

Brasilodopsis amazonica gen. et sp. nov.

urn:lsid:zoobank.org:act:52B493C0-AC19-49EB-95BD-77E4805A9957

Figs 13–17

“ Cypridopsis ” n. gen. 1 n. sp. – Higuti & Martens 2016: appendix 1.

Diagnosis

LV and RV with well-developed anterior calcified inner lamella, with greatest height in both valves situated in the middle of the smoothly curved dorsal margin. A2 with the natatory setae reaching beyond the tip of the end claws and seta g absent. Valve surface densely set with rimmed pores in shallow pits. T1 with seta d present in female, absent in male. CR present in female only. Male prehensile palps asymmetrical; Rpp with first segment rather stout and second segment with triangular lobe; Lpp with first segment elongated and second segment sickle shaped. Hemipenis with ventral lobe of ms rounded and ventral lobe of ls bird head-shaped; with two loops in post-labyrinthal spermiduct.

Etymology

The species is named after the area from which it is here described, namely Amazonia, Brazil.

Material examined

Holotype BRAZIL • ♂; Amazon River floodplain, Castanho Lake; 3°24′4.6″ S, 60°13′26.9″ W; 17 May 2012; J. Higuti leg.; with soft parts dissected in glycerine in a sealed slide, valves stored dry in a micropalaeontological slide; sample AMA 79; MZUSP 41852 .

Allotype BRAZIL • ♀; Amazon River floodplain, Castanho Lake; 3°24′4.6″ S, 60°13′26.9″ W; 17 May 2012; J. Higuti leg.; with soft parts dissected in glycerine in a sealed slide, valves stored dry in a micropalaeontological slide; sample AMA 79; MZUSP 41853 .

Paratypes BRAZIL • 2 ♂♂; Amazon River floodplain , Castanho Lake ; 3°24′4.6″ S, 60°13′26.9″ W; 17 May 2012; J. Higuti leg.; with soft parts dissected in glycerine in sealed slides, LV and RV lost; sample AMA 79; MZUSP 41854 , MZUSP 41855 • 1 ♂; Amazon River floodplain , Castanho Lake; 3°24′4.6″ S, 60°13′26.9″ W; 17 May 2012; J. Higuti leg.; with soft parts dissected in glycerine in a sealed slide, LV stored dry in a micropalaeontological slide after use for SEM; sample AMA 79; MZUSP 41856 • 3 ♂♂; Amazon River floodplain , Castanho Lake; 3°24′4.6″ S, 60°13′26.9″ W; 17 May 2012; J. Higuti leg.; carapaces stored dry in micropalaeontological slides after use for SEM; sample AMA 79; MZUSP 41857 to MZUSP 41859 • 1 ♀; Amazon River floodplain , Castanho Lake; 3°24′4.6″ S, 60°13′26.9″ W; 17 May 2012; J. Higuti leg.; with soft parts dissected in glycerine in a sealed slide, both LV and RV lost; sample AMA 79; MZUSP 41861 • 1 ♀; Amazon River floodplain , Castanho Lake; 3°24′4.6″ S, 60°13′26.9″ W; 17 May 2012; J. Higuti leg.; with soft parts dissected in glycerine in sealed slides, valves stored dry in micropalaeontological slides; sample AMA 79; MZUSP 41860 • 1 ♀; Amazon River floodplain , Castanho Lake; 3°24′4.6″ S, 60°13′26.9″ W; 17 May 2012; J. Higuti leg.; with soft parts dissected in glycerine in sealed slides, valves stored dry in micropalaeontological slides after use for SEM; sample AMA 79; MZUSP 41862 • 3 ♀♀; Amazon River floodplain , Castanho Lake; 3°24′4.6″ S, 60°13′26.9″ W; 17 May 2012; J. Higuti leg.; carapaces stored dry in micropalaeontological slides after use for SEM; sample AMA 79; MZUSP 41863 to MZUSP 41865 .

Other material examined

BRAZIL • 2 ♀♀; Amazon River floodplain , Fuxico Lake; 3°25′21.5″ S, 60°29′13″ W; 16 May 2012; J. Higuti leg.; UEM-AMA 69; JH729 , JH730 • 3 ♀♀; Amazon River floodplain , Jamauacá Lake; 3°22′33.1″ S, 60°17′55.1″ W; 17 May 2012; J. Higuti leg.; UEM-AMA 73; JH731 to JH733 .

Measurements of illustrated specimens

See Table 2 .

Description

Remark: most of the material was slightly to considerably decalcified, so that dissections and SEM illustrations were difficult. The holotype male has two intact valves, but these were not used for SEM, because of the risk of damaging them. Other specimens were used for illustration, but no intact RV was available.

Male

LVi ( Fig. 13A–C – slightly distorted owing to decalcification) with well-developed anterior calcified inner lamella, posterior calcified inner lamella narrow; an inner list running along and parallel to anterior,

ventral and posterior valve margin, inwardly displaced anteriorly and posteriorly; anterior inner list running almost to the dorsal margin, posterior inner list running to the dorsal margin.

RVi (not illustrated) with well-developed anterior calcified inner lamella, posterior calcified inner lamella narrow; short anteroventral trace of an inner list and posteroventrally with an elevated inwardly displaced inner list and a submarginal selvage, both running parallel to the valve margin.

Greatest height in both valves situated in the middle of the smoothly curved dorsal margin. CpRl ( Fig. 13E ) elongated; dorsal margin smoothly arched; with the greatest height in the middle; external valve surface densely set with rimmed pores in shallow pits ( Fig. 13D ). CpD ( Fig. 13F, H ) and CpV ( Fig. 13G ) sub-ovate; with greatest width situated behind the middle; anterior margin pointed, posterior margin rounded; LV overlapping RV along the anterior, ventral and posterior margins, with a broad flap in the middle.

A1 (not illustrated) with seven segments. First segment large, ventrally with two long apical hirsute setae; dorsally with one short subapical hirsute seta, and with small Wouter’s organ. Second segment subquadrate, with one short dorsal seta and a small ventral Rome organ. Third segment with two apical setae (the shorter ventral seta almost reaching the tip of the fourth segment; the longer dorsal seta reaching the edge of the fifth segment). Fourth segment with three apical setae, two long dorsal ones, and one ventral seta, the latter slightly shorter than the length of the fifth segment. Fifth segment with three apical setae, two long dorsal setae and one short ventral seta, the latter reaching half the length of the sixth segment. Sixth segment with four long apical setae. Terminal segment with two long setae, one shorter, but still elongated, aesthetasc Ya and one shorter seta, the latter almost the same length of the aesthetasc Ya.

A2 ( Fig. 14A–B ) with protopodite, exopodite and three-segmented endopodite. Protopodite ventrally with three setae: two unequal but short setae, one long apical seta reaching beyond the tip of the terminal segment. Exopodite reduced to a small plate with one long seta (reaching beyond the tip of the terminal segment) and two sub-equal short setae. First endopodal segment ventrally with aestethasc Y (more than ⅓ of the length of this segment), one long hirsute ventral seta (reaching beyond the tip of the terminal segment), and five hirsute natatory setae, reaching beyond the tip of the end claws, and one short accompanying seta, about ½ of the length of the second endopodal segment. Second endopodal segment with two unequal but long dorsal setae, one short hirsute ventral seta t; apically with three claws (G1, G2, z1) and three setae (G3, z2, z3). Terminal segment ( Fig. 14B ) with two claws, one long (GM) and one short (Gm) and one aesthetasc y3 with accompanying seta (slightly longer than the aesthetasc y3). Seta g absent.

Rake-like organ (not illustrated) stout, solid, T-shaped, with seven apical teeth.

Md-palp (not illustrated) with four segments. First segment with two long plumose setae (S 1 and S 2), one long smooth seta and one short smooth seta α. Second segment with three dorsal setae (two long and one shorter, ca ⅔ the length of the two longer ones); ventrally with one hirsute seta β and four long setae (three equally long, and one slightly shorter). Third segment with three groups of setae; dorsally one group of three unequal but long setae; laterally with one hirsute and stout apical seta γ and three smooth setae; ventrally with three unequal shorter setae. Terminal segment with three claws and three setae.

Md-coxa (not illustrated) elongated, dorsally with a short seta, and with strong and apical teeth, interspaced with some setae.

Mx1 (not illustrated) consisting of three masticatory lobes (endites), a two-segmented palp and a large branchial plate (not illustrated). Branchial plate elongated, with ca 16 respiratory rays, some quite short, others longer. First segment of palp with five setae (apically with four unequal but long setae and one short subapical seta, about ¼ of the longest one). Terminal segment of palp ca twice as long as basal width, apically with two claw-like setae and two setae. Third endite apically with two serrated claws and several setae. First endite at its base with two unequal setae and apically with ca five unequal, sideways directed bristles.

T1 protopodite ( Fig. 15A–C ) apically with a group of eight hirsute setae, and two short setae a inserted in the middle, seta d absent. Endopodites ( Fig. 15B–C ) asymmetrical prehensile palps: Rpp ( Fig. 15B ) with first segment rather stout, with two small subapical spines, second segment with triangular lobe, with uneven dorsal and slightly curved distal margin. Lpp ( Fig. 15C ) with first segment elongated, with two sub-apical spines, second segment sickle-shaped, with swollen basis and blunt distal part.

T2 (not illustrated) with protopodite, a ‘knee’-segment and four endopodite segments. Protopodal segment without seta d1. ‘Knee’-segment with one short subapical seta d2. First endopodal segment with one apical hirsute seta e, reaching the middle of the second endopodal segment. Second endopodal segment with one apical hirsute seta f, reaching beyond the tip of the fifth segment. Third endopodal segment with one subapical hirsute seta g, approximately half of the length of the seta f. Terminal segment with one apical serrated claw h2, one short hirsute subapical seta h1 and a very short seta h3.

T3 ( Fig. 14C ) with three segments. First segment with two unequal long setae d2 and dp and one shorter seta d1. Second segment with one subapical seta e, reaching beyond the middle of the third segment. Third segment medially with one seta f, about ½ the length of the third segment. Distal part of third segment with a pincer structure, one small spine-like structure (h1), one long subapical seta h3, about 1.5× the length of the broad seta h2, the latter set with spine-like setulae.

Zenker’s organ ( Fig. 15D ) about 4 times as long as wide, with approximately 10 series of sw.

Hemipenis ( Fig. 15E–M ) with ventral lobe of ms rounded, ventral lobe of ls bird head-shaped with bluntly pointed distal beak. Post-labyrinthal spermiduct with two loops: one large, one much smaller ( Fig. 15E ).

Remark: the outline of the hemipenis can show some variability within one specimen and between specimens. Therefore, the hemipenis outlines of four males have been illustrated in Fig. 15F–M .

Female

Remark: also here, some specimens were decalcified and this caused some distortion of the single valves in the SEM illustrations.

LVi ( Fig. 16A, C–D ), RVi ( Fig. 16B, E–F ), CpRl ( Fig. 16G ), CpD ( Fig. 16H ) and CpV ( Fig. 16I ) as in the male.

A1, Rake-like organ, Md-coxa, Mx1 and T2 (not illustrated) as in the male.

A2 ( Fig. 17A–B ) with protodopodite, exopodite and three-segmented endopodite. Protopodite ventrally with three setae: two unequal but short setae, one long apical seta reaching beyond the tip of the terminal segment. Exopodite reduced to a small plate with one long seta (reaching beyond the tip of the terminal segment) and two sub-equal short setae. First endopodal segment ventrally with aestethasc Y (ca ¼ of the length of this segment), one long hirsute ventral seta (reaching beyond the tip of the terminal segment), and five hirsute natatory setae, reaching beyond the tip of the end claws, and one short accompanying seta, about ½ of the length of the second endopodal segment. Second endopodal segment with two unequal, but long dorsal setae, four ventral setae t (two unequal but long, one ca e half of the length of the longest setae, and one short, approximately ¼ of longest setae); apically with three claws (G1, G2, G3) and three setae (z1, z2, z3). Terminal segment ( Fig. 17B ) with two claws, one long (GM) one short (Gm) and one aesthetasc y3 with accompanying seta, slightly longer than y3. Seta g absent.

T1 ( Fig. 17C ) protopodite with a group of eight hirsute setae; two short seta a, one long seta d. Endopodite consisting of three long plumose setae.

T3 ( Fig. 17D ) with three segments. First segment with two unequal long setae d2 and dp and one shorter seta d1. Second segment with one subapical seta e, almost smaller than the half of the third segment. Third segment medially with one seta f, about ⅓ the length of the third segment. Distal part of third segment with a pincer structure, one small spine-like structure h1, one long subapical seta h3, slightly longer than the broad seta h2, the latter set with spine-like setulae.

CR ( Fig. 17E ) with elongated base (2–3 times as long as wide), one subapical short seta and one long apical seta (ca 3–5 times the length of the base).

Differential diagnosis

Cp sub-ovate, slightly more elongated and with smoothly curved dorsal margin (with blunt dorsal corner in Brasilodopsis baiabonita gen. et sp. nov.). Posterior inner list in LV more slender than in B. baiabonita gen. et sp. nov. (see Table 3 ). External valve surface densely set with rimmed pores in shallow pits (smooth, with sparse setae and pores in B. baiabonita gen. et sp. nov.). Hemipenis outline similar in both species, but distal segments of prehensile palps with subtle differences.

Ecology and distribution

Brasilodopsis amazonica gen. et sp. nov. was recorded only from the Amazon River floodplain, in association with several aquatic macrophytes. The range of the water temperature was between 31.5 and 32.9°C. The pH range remained slightly acid (6.4 and 6.7 – hence possibly the decalcified valves). The ranges of electrical conductivity and dissolved oxygen were from 41.5 to 67.1 µS. cm-1, and from 0.4 to 3 mg.L- 1, respectively (see Table 4 ).

Figures

Fig. 13. Brasilodopsis amazonica gen. et sp. nov. from Amazon River floodplain, ♂. A. LVi (MZUSP 41856). B. LVi, detail of anterior part (MZUSP 41856). C. LVi, detail of posterior part (MZUSP 41856). D. CpRl, detail of Cp surface (MZUSP 41857). E. CpRl (MZUSP 41857). F. CpD (MZUSP 41858). G. CpV (MZUSP 41859). H. CpD, detail of Cp surface (MZUSP 41858). Scale bars: A, E–G = 300 µm; B–D, H = 100 µm.

Fig. 14. Brasilodopsis amazonica gen. et sp. nov. from Amazon River floodplain, ♂. A. A2, without the terminal segment (MZUSP 41854). B. A2, terminal segment (MZUSP 41854). C. T3 (MZUSP 41854). Abbreviations: see text and Material and methods. Scale bars: 50 µm.

Fig. 15. Brasilodopsis amazonica gen. et sp. nov. from Amazon River floodplain, ♂. A. T1 (MZUSP 41852). B. Rpp (MZUSP 41852). C. Lpp (MZUSP 41852). D. Zenker’s organ (MZUSP 41852).E–G. Hemipenis (MZUSP 41852).H–I. Hemipenis (MZUSP 41856).J–K. Hemipenis (MZUSP 41854). L–M. Hemipenis (MZUSP 41855). Abbreviations: see text and Material and methods. Scale bars: 50 µm.

Fig. 16. Brasilodopsis amazonica gen. et sp. nov. from Amazon River floodplain, ♀. A. LVi (MZUSP 41862). B. RVi (MZUSP 41862). C. LVi, detail of posterior part (MZUSP 41862). D. LVi, detail of anterior part (MZUSP 41862). E. RVi, detail of anterior part (MZUSP 41862). F. RVi, detail of posterior part (MZUSP 41862). G. CpRl (MZUSP 41863). H. CpD (MZUSP 41864). I. CpV (MZUSP 41865). Scale bars: A–B, G–I = 300 µm; C–F = 100 µm.

Fig. 17. Brasilodopsis amazonica gen. et sp. nov. Amazon River floodplain, ♀. A. A2, without the terminal segment (MZUSP 41853). B. A2, terminal segment (MZUSP 41853). C. T1 (MZUSP 41861). D. T3 (MZUSP 41862). E. CR (MZUSP 41861). Abbreviations: see text and Material and methods. Scale bars: 50 µm.