Brasilodopsis baiabonita gen. et sp. nov.

urn:lsid:zoobank.org:act: A3DE9437-5A51-4DA5-A186-470C197A8050

Figs 2–12

“ Cypridopsis ” n.gen. 1 n. sp. – Higuti et al. 2009: 664, table 1; 2010: 267, table 2; 2017b: 7, table 2. —

Matsuda et al. 2015a: 326, table 1. — Pereira et al. 2017: 327, 329, table 2, fig. 5. — Conceição et al. 2018: 184, table 3.

“ Cypridopsis ” n. gen. n.sp. 2 – Campos et al. 2017: 38, table 2.

“ Cypridopsis ” n. gen. 2 n. sp. – Higuti et al. 2017a: 5, appendix 1.

“ Cypridopsis ” sp. 1 n. gen. n.sp. – Campos et al. 2018: 6, table 2; 2019: 375, table 1.

“ Cypridopsis ” n. gen. 1 n. sp. 1 – Higuti et al. 2020: 2, table S1.

Diagnosis

Cp in dorsal view with LV overlapping RV at anterior and posterior sides. LV and RV with welldeveloped anterior calcified inner lamella, with the greatest height in both valves situated in the middle of the dorsal margin. A2 with the natatory setae reaching beyond the tip of the end claws; seta g absent. T1 with seta d absent in males, present in females. CR present only in female. Male prehensile palps asymmetrical. Rpp with first segment elongated 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 and with two loops in the post-labyrinthal spermiduct.

Etymology

The species is named after its type locality, Baia Bonita River in the State of Mato Grosso do Sul (Brazil).

Type material examined

Holotype BRAZIL • ♂; Bonito, State of Mato Grosso do Sul, Baia Bonita River; 21°9′57.4″ S, 56°26′26″ W; 10 Jun. 2003; J. Higuti and K. Martens leg.; with soft parts dissected in glycerine in a sealed slide, valves stored dry in a micropalaeontological slide; sample PAN 36; MZUSP 41825.

Allotype BRAZIL • ♀; Bonito, State of Mato Grosso do Sul, Baia Bonita River; 21°9′57.4″ S, 56°26′26″ W; 10 Jun. 2003; J. Higuti and K. Martens leg.; with soft parts dissected in glycerine in a sealed slide, valves stored dry in a micropalaeontological slide; sample PAN 36; MZUSP 41826.

Paratypes BRAZIL • 2 ♂♂; Bonito, State of Mato Grosso do Sul, Baia Bonita River; 21°9′57.4″ S, 56°26′26″ W; 10 Jun. 2003; J. Higuti and K. Martens leg.; with soft parts dissected in glycerine in sealed slides, valves stored dry in micropalaeontological slides; sample PAN 36; MZUSP 41827, MZUSP 41828 • 1 ♂; Bonito, State of Mato Grosso do Sul, Baia Bonita River; 21°9′57.4″ S, 56°26′26″ W; 10 Jun. 2003; J. Higuti and K. Martens leg.; with soft parts dissected in glycerine in a sealed slide, LV stored dry in a micropalaeontological slide (RV lost); sample PAN 36; MZUSP 41829 • 2 ♂♂; Bonito, State of Mato Grosso do Sul, Baia Bonita River; 21°9′57.4″ S, 56°26′26″ W; 10 Jun. 2003; J. Higuti and K. Martens leg.; with soft parts dissected in glycerine in sealed slides, valves stored dry in micropalaeontological slides (both LV lost); sample PAN 36; MZUSP 41830, MZUSP 41831 • 3 ♀♀; Bonito, State of Mato Grosso do Sul, Baia Bonita River; 21°9′57.4″ S, 56°26′26″ W; 10 Jun. 2003; J. Higuti and K. Martens leg.; with soft parts dissected in glycerine in sealed slides, valves stored dry in micropalaeontological slides; sample PAN 36; MZUSP 41832 to MZUSP 41834 • 1 ♀; Bonito, State of Mato Grosso do Sul, Baia Bonita River; 21°9′57.4″ S, 56°26′26″ W; 10 Jun. 2003; J. Higuti and K. Martens leg.; with soft parts dissected in glycerine in a sealed slide, RV stored dry in a micropalaeontological slide (LV lost); sample PAN 36; MZUSP 41835 .

Other material illustrated

BRAZIL • 4 ♂♂; Bonito, State of Mato Grosso do Sul, Formoso River; 21°10′26.5″ S, 56°26′56″ W; 10 Jun. 2003; J. Higuti and K. Martens leg.; with valves and carapaces stored dry in micropalaeontological slides after use for SEM; sample PAN 33; MZUSP 41836 to MZUSP 41839 • 4 ♀♀; Bonito, State of Mato Grosso do Sul, Formoso River; 21°10′26.5″ S, 56°26′56″ W; 10 Jun. 2003; J. Higuti and K. Martens leg.; valves and carapaces stored dry in micropalaeontological slides after use for SEM; sample PAN 33; MZUSP 41840 to MZUSP 41843 • 1 ♀; Araguaia River floodplain, Crixas IV Lake; 13°20′37.5″ S, 50°36′40″ W; 2 Nov. 2011; J. Higuti leg.; with soft parts dissected in glycerine in a sealed slide, valves stored dry in a micropalaeontological slide after use for SEM; sample ARA 05; MZUSP 41844 • 3 ♀♀; Araguaia River floodplain, Crixas IV Lake; 13°20′37.5″ S, 50°36′40″ W; 2 Nov. 2011; J. Higuti leg.; carapaces stored dry in micropalaeontological slides after use for SEM; sample ARA 05; MZUSP 41845 to MZUSP 41847 • 1 ♀; Upper Paraná River floodplain, Pombas Lake; 22°47′56.8″ S, 53°21′36.6″ W; 22 Mar. 2018; J. Higuti, K. Martens and students leg.; with soft parts dissected in glycerine in a sealed slide, valves stored dry in a micropalaeontological slide after use for SEM; sample PAR 1520; MZUSP 41848 • 3 ♀♀; Upper Paraná River floodplain, Pombas Lake; 22°47′56.8″ S, 53°21′36.6″ W; 22 Mar. 2018; J. Higuti, K. Martens and students leg.; carapaces stored dry in micropalaeontological slides after use for SEM; sample PAR 1520; MZUSP 41849 to MZUSP 41851 .

Other material examined

BRAZIL • 4 ♀♀; South Matogrossense Pantanal, Corumba Road, pool 2; 19°35′38″ S, 57°8′3″ W; 4 Jun. 2003; J. Higuti, K. Martens and K.F. Roche leg.; UEM-PAN 14; JH326 to JH329 • 3 ♀♀; South Matogrossense Pantanal, BEP wetland 1; 19°34′38″ S, 57°1′11″ W; 7 Jun. 2003; J. Higuti, K. Martens and K.F. Roche leg.; UEM-PAN 26; JH540, JH541, NA028 • 1 ♀, male specimen subsequently lost; South Matogrossense Pantanal, Miranda I River; 19°25′38.2″ S, 57°18′58.4″ W; 23 Aug. 2011; L.F.M. Velho and L.C. Rodrigues leg.; UEM-PAN 63; NA030 • 6 ♀♀; South Matogrossense Pantanal, Miranda III River; 19°26′23.1″ S, 57°18′21.4″ W; 23 Aug. 2011; L.F.M. Velho and L.C. Rodrigues leg.; UEM- PAN 69; JH1060 to JH1065 • 1 ♀; South Matogrossense Pantanal, Corumba Road, lake 1; 19°35′33″ S, 57°8′19″ W; 4 Jun. 2003; J. Higuti, K. Martens and K.F. Roche leg.; UEM-PAN 12; JH338 • 3 ♀♀; Araguaia River floodplain, Comprido II Lake; 12°51′8.8″ S, 50°34′4.8″ W; 12 Mar. 2012; J. Higuti and K. Martens leg.; UEM-ARA 99; JH1479 to JH1481 • 4 ♀♀; Upper Paraná River floodplain, Caracu Stream; 22°46′6″ S, 53°15′28″ W; 17 Mar. 2004; J. Higuti and K. Martens leg.; UEM-PAR 100; JH701, KM3453 to KM3455 .

Measurements of illustrated specimens

See Table 2.

Description

Male

LVi (Figs 2A, C–D, 3A, C–D) with well-developed anterior calcified inner lamella, posterior calcified inner lamella narrow; a well-developed inner list running along and parallel to anterior, ventral and posterior valve margin, largely inwardly displaced anteriorly and posteriorly; anterior inner list running almost to the dorsal margin, posterior inner list elevated and running to the dorsal margin. Anteriorly with a submarginal selvage.

RVi (Figs 2B, E–F, 3B, E–F) 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 dorsal margin, indicated by a blunt corner. CpRl (Fig. 3G) with a triangular shape, with greatest height in the middle. CpD (Fig. 3H) external surface sparsely set with shallow pits and short setae and CpV (Fig. 3I) sub-ovate, with greatest width slightly behind the middle; anterior margin more pointed, posterior margin more rounded; LV overlapping RV along anterior, ventral and posterior margins, with an extended flap in the middle of the ventral side.

A1 (Fig. 4A) 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 (Wo). Second segment subquadrate, with one short dorsal seta and a small ventral Rome organ (R). Third segment with two apical setae (the shorter ventral seta almost reaching the tip of the fourth segment; the longer dorsal seta slightly shorter than the length 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 terminal segment. Sixth segment with four long apical setae. Terminal segment with two unequally long setae, aesthetasc Ya and one shorter seta, the latter almost the same length of the aesthetasc Ya.

A2 (Fig. 4C–D) 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 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. 4D) 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 (Fig. 4B) stout, solid, T-shaped, with seven apical teeth.

Md-palp (Fig. 5B) 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 (Fig. 5A) elongated, dorsally with a short seta, and with strong and apical teeth, interspaced with some setae.

Mx1 (Fig. 5C – chaetotaxy not complete) 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 (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 (Fig. 6A–C) protopodite apically with a group of eight hirsute setae, and two short setae a inserted in the middle, seta d absent. Endopodites (Fig. 6B–C) asymmetrical prehensile palps: Rpp (Fig. 6B) with first segment elongated, with two subapical spines, second segment with triangular lobe, with uneven dorsal and straight distal margin. Lpp (Fig. 6C) with first segment elongated, with two sub-apical spines, second segment sickle-shaped, with swollen basis and bluntly pointed distal part.

T2 (Fig. 6D) 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 tip of the second endopodal segment. Second endopodal segment with one apical hirsute seta f, reaching beyond the tip of the terminal 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. 6E) with three segments. First segment with two unequal long (d2, dp) and one shorter setae d1. Second segment with one subapical seta e, reaching 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 twice of the length of the broad seta h2, the latter set with spine-like setulae.

Zenker’s organ (Fig. 6F) about four times as long as wide, with ca 10 sw.

Hemipenis (Fig. 6G) with distal lobe of ms rounded, distal lobe of ls bird head-shaped, with rounded margins, and a bluntly pointed distal beak.

Female

LVi (Figs 7A, C–D; 8A, C–D), RVi (Figs 7B, E–F; 8B, E–F), CpRl (Fig. 8G), CpD (Fig. 8H) and CpV (Fig. 8I) as in the male.

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

A2 (Fig. 9A–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 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 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. 9B) 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. 9C) Protopodite apically with a group of eight hirsute setae; two short setae a and one long seta d. Endopodite apically with three subequal long and plumose setae.

T2 (Fig. 10A) largely as in the male, 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 tip of the second endopodal segment. Second endopodal segment with one apical hirsute seta f, just reaching the tip of the fifth segment. Third endopodal segment with one subapical hirsute seta g, approximately ⅔ 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 (not visible here).

T3 (Fig. 10B) largely as in the male, with three segments. First segment with two unequal long (d2, dp) and one shorter setae d1. Second segment with one subapical seta e, reaching 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 twice the length of the broad seta h2, the latter set with spine-like setulae.

CR (Fig. 10C) with cylindrical base, one subapical short seta and one long apical seta (ca 3 times the length of the base).

Differential diagnosis

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

Ecology and distribution

Brasilodopsis baiabonita gen. et sp. nov. was recorded from three tropical Brazilian floodplains (Araguaia, Pantanal and Paraná), associated with different species of macrophytes and sediment (mud, sand). The water temperature ranged between 18.5 and 32.6°C. The pH ranged from acid (5) to basic (8.9). The range of electrical conductivity was between 14 and 415 µS. cm-1 and the values of dissolved oxygen varied from 0.1 to 7.8 mg.L- 1 (see Table 4).

Remarks

In order to show that valve and Cp morphologies are similar in all three floodplains, we here also illustrate this in Figs 11 (Araguaia) and 12 (Paraná), albeit for all-female populations only.