Five new species of Candoninae (Crustacea, Ostracoda) from the alluvial valley of the Upper Paraná River (Brazil, South America)

The present paper describes five new species of candonid ostracods in two genera: Pseudocandona agostinhoi sp. nov., P. cillisi sp. nov., P. claudinae sp. nov., Candobrasilopsis elongata sp. nov. and C. acutis sp. nov. The three species of Pseudocandona belong to the caribbeana-group in this genus. With the two new species of Candobrasilopsis, this genus now comprises four species. Candobrasilopsis elongata sp. nov. is the most common of the five new species described here, while C. acutis sp. nov. and P. claudinae sp. nov. are known from one locality only, which is furthermore the same for both species: a small streamlet entering the Paraná River. With the description of the present five species, the number of species known from the Paraná River alluvial valley, including the Taquaruçu lakes, now amounts to 49.


Introduction
There are about 2000 Recent non-marine ostracod species in the world (Martens et al. 2008). Close to 300 of these species have been described and reported from South America and more than 100 species are now known from Brazil (Martens & Behen 1994;Higuti et al. 2009aHiguti et al. , 2013Higuti & Martens 2012a, 2012b. Recent work on the alluvial valley of the Upper Paraná River (Higuti et al. 2007(Higuti et al. , 2009b(Higuti et al. , 2009cMormul et al. 2010) has contributed significantly to the general knowledge of ecology and biogeography of Brazilian freshwater ostracods, especially those occurring in the pleuston of floating plants. Floating plants such as species in the genera Eichhornia, Pistia and Salvinia are typical of South American (floodplain) lakes, and pleuston, the animal communities living in the root systems of such plants, are thus typical of such lakes.

R e s e a r c h a r t i c l e
urn:lsid:zoobank.org:pub:3C2078C7-B4B0-4976-8CED-CD2AA97E9E8F The ecological realm of pleuston, next to the plankton and benthos (see Por 1995), is especially important in floodplain lakes. Sediments in floodplain lakes have low oxygen levels most of the time and sudden water level rise can render sediments anoxic virtually overnight. Thus, floating plants become important substrates for colonization by ostracods, since these macrophytes will simply follow rising water levels and local variables such as oxygen will change minimally on the root systems of the floating vegetation.
Many otherwise benthic organisms can thus be found in the pleuston in South American floodplain lakes.
The collections made to study the ecology of the ostracods in the pleuston in the alluvial valley of the Upper Paraná River (Higuti et al. 2007(Higuti et al. , 2009b(Higuti et al. , 2009cMormul et al. 2010) also served for taxonomic revisions and several new species and genera of ostracods have meanwhile been described from lakes, river beds and channels of this floodplain (Higuti et al. 2009a(Higuti et al. , 2013Higuti & Martens 2012a, 2012b. Most of these new taxa belong to the family Cyprididae; only one paper thus far treated two species of Candonidae from this floodplain in detail (Higuti & Martens 2012b), describing a new genus and species, Candobrasilopsis rochai Higuti & Martens, 2012, and redescribing and generically transferring another species, Candobrasilopsis brasiliensis (Sars, 1901).  Table 1. Localities (and some of their characteristics) from which the five new species of candonids were collected. Locality names of 1 to 9 are from the Ivinhema River System, 10 to 18 from the Baía River System, 19 to 22 from the Paraná River System and locality 23 is from the Taquaruçu System. Bold = type localities of the new species. WT = water temperature ( o C), EC = electrical conductivity (µS cm -1 ), DO = dissolved oxygen (mg L -1 ), Pa = Pseudocandona agostinhoi sp. nov., Pc = P. cillisi sp. nov., Pcl = P. claudinae sp. nov., Ce = Candobrasilopsis elongata sp. nov., Ca = C. acutis sp. nov.  The nomenclature of the limb chaetotaxy mostly follows Broodbakker & Danielopol (1982), for the second antenna we follow the revised model proposed by Martens (1987), while for the second and third thoracopods, Meisch's nomenclature (2000) is followed. Higher taxonomy of the Ostracoda follows the synopsis by Horne et al. (2002).  Kaufmann, 1900 Genus Pseudocandona Kaufmann, 1900

Diagnosis
Carapace variously shaped, usually relatively short and stout, rarely elongated or triangular in lateral view. Surface of adults valves smooth or pitted, usually with long, stiff and perpendicularly attached setae. LV overlaps RV. Setal group of the second segment of the mandibular palp with 3 to 5 setae (plus beta-seta). Basal segment of T3 with 3 setae (d1, d2 and dp), medial seta of penultimate segment always missing, terminal segment with one short (h1) and two long setae (h2 and h3). Hemipenis with at least three distal lobes (a, b, h).
Higuti J. & MARtENS K., Five new Candoninae species from Brazil Remarks 1. All three new species described here have a group of 4 ventral setae (+ 1 β-seta) on the second segment of the Md-palp. In addition, claws G1 and GM of the A2 (in females) and claws G2, GM and z1 (in males) are long. The combination of these characters places the three new species in the caribbeana-group of the genus according to the scheme of Namiotko & Danielopol (2004). See the general discussion of the present paper for further discussion on this species group. 2. The genus Pseudocandona is speciose, and most species occur in the Palaearctic and the Nearctic, including a large radiation in the ancient Lake Baikal (Siberia). In the differential diagnoses in the present paper we will only compare our new species to those already described from the Neotropical region, although of course their morphology was also checked against the Holarctic species of which good descriptions and illustrations are available. 3. Pseudocandona agostinhoi sp. nov. is described in full, the descriptions of the other two new species in this genus are abbreviated.

Diagnosis
Carapace rather elongated in lateral view, and with LV overlapping RV on all sides, especially at anterior and posterior extremities. Anterior calcified inner lamella in both valves relatively broad. LV with anterior and posterior inner list, situated well away from the valve margin. Second segment of Md palp ventrally with 4 setae (+ 1 β-seta). Prehensile palps distally hook-like and set with two thin, subapical setae. Penultimate segment of T3 not divided; seta h1 slightly more than half the length of seta h2. Hemipenis with lobe a small and sub-quadrate, with rounded distal margin; lobes b and h largely overlapping, except on ventro-apical side, asymmetrically rounded and pointed towards the ventral side.

Etymology
The new species is named after Prof. Dr Angelo Antonio Agostinho (Nupelia, Universidade Estadual de Maringá, Maringá, Brazil), in recognition of his vast contributions to the knowledge on the biodiversity and the conservation of Brazilian freshwater environments, mainly in ichthyology, and also to acknowledge him for being one of the founders of Nupelia (Research Group in Limnology, Ichthyology and Aquaculture).

Type material
All type material was collected on 16 Jul. 2012 by JH and students, by washing roots of Eichhornia crassipes (PAR 710) in a bucket and by filtering the material in a hand net with mesh size 160 µm. See Table 1 for measurements of water chemistry at time of collecting.
Holotype ♂, with soft parts dissected in glycerine in a sealed slide, and with valves stored dry in a micropalaeontological slide (MZUSP 32653).

Differential diagnosis
Pseudocandona agostinhoi sp. nov. can be distinguished from P. geratsi Broodbakker, 1983 by the shape of the valves (dorsal margin straight and oblique in the middle in P.a., rounded in P.g.), of the hemipenis (lobe a with distal margin rounded in P.a., straight in P.g.) and of the prehensile palps (Rpp evenly rounded in P.a., with blunt angles in P.g.; Lpp more narrow and position of setae more distal in P.a.). Pseudocandona antilliana Broodbakkker, 1983 also has the middle part of the dorsal margin of the valves straight in the female, but running parallel to the ventral margin, not sloping as in P. agostinhoi sp. nov., while also in this species the distal margin of lobe a of the hemipenis is straight (rounded in P. agostinhoi sp. nov.). Pseudocandona caribbeana Broodbakker, 1983 andP. cubensis Broodbakkker, 1983 both have short and high carapaces, with straight dorsal margin parallel to the ventral margin, and with at least P. caribbeana with an anterior rostrum in dorsal view. Both of the latter species are known from females only.
Pseudocandona agostinhoi sp. nov. differs from P. annae (Mehes, 1914) in several aspects of its morphology. The latter species is more elongated with a longer straight section of the dorsal margin. In P. agostinhoi sp. nov., the LV overlaps the RV on all sides, and especially strongly along the anterior and posterior margins, whereas the overlap appears to be minimal according to the drawings by Mehes (1914). The Rpp has a fully rounded dorsal-distal part in P. agostinhoi sp. nov., whereas this has a straight margin in P. annae. Finally, lobes a, b and h of the hemipenis in P. agostinhoi sp. nov. are almost equally long, whereas lobe a is much shorter in P. annae.  3B) with basal segment with 2 relatively short dorsal setae, one at ca. mid-length, the other sub-apical, and two dorsal, sub-apical setae: one long, the other slightly longer than half the length of the first. Second segment with one dorso-apical seta (reaching beyond basis of fourth segment), no ventro-apical seta present. Third segment with one sub-apical dorsal set, reaching beyond basis of fourth segment, no ventral seta present. Fourth and fifth segments with two longer dorso-apical and 1 shorter ventro-apical setae. Sixth and seventh segments most elongate of all; sixth segment with two longer dorso-apical and one shorter ventro-apical setae. Seventh (terminal segment) slightly sinuous, bearing one short and two longer setae and one aesthetasc Ya, the latter shorter than the shorter seta. A2 ( Fig. 3A) with basal segment broad, wide and relatively long, basally with 2 unequal setae, one relatively long, the other ca. half as long as the first; one long ventro-apical seta also present. Remnant of exopod consisting of a short plate, with one long and two unequal shorter setae. Endopod consisting of 4 segments (penultimate segment divided). First endopodal segment long, carrying one long aesthetasc Y at the base of the ventral side, and one long and one short ventro-apical setae. Second endopodal segment shorter and smaller, rectangular with one ventral aesthetasc y1 inserted about mid length, 3 t-setae, with t1 almost same length as t2, t2 and t3 modified into male-bristles; dorso-apically with 1 seta. Third endopodal segment with apical chaetotaxy sexually dimorphic, with z1 and z3 being short setae, z2 being modified into a long claw; G2 a long claw, G1 a long seta and G3 a short seta, aesthetasc y2 short and ventro-apically inserted. Terminal (fourth) segment small (Fig. 3B), distally with claws GM (long) and Gm (short), aesthetasc y3 with its companion seta, fused at the basis and of unequal length, and seta g, longer than y3.

Description of male
Md with coxa ( Fig. 3F) relatively slender, distally set with a series of strong teeth.
Md-palp (Fig. 4B) consisting of 4 segments. Basal segment dorsally carrying the respiratory plate (not fully shown), ventro-apically with 2 long setae, 1 hirsute s1 seta, the other seta smooth, the minute alpha seta, and seta s2 short, stout and hirsute. Second segment dorso-apically with 2 setae of unequal length, ventro-apically with a group of 5 setae: 3 long, one shorter, and the short beta-seta. Third segment with a group of 3 smooth dorso-subapical setae (2 long and one shorter), a central group of two setae, the ventral-most one being the gamma seta, and ventro-apically with 2 smooth setae. Terminal segment sub-quadrate, apically set with two large claw-like setae, one distally hirsute and three shorter setae of unequal length. Mx1 (Fig. 4A) with a basal (basipodite) part carrying a large respiratory plate (exopodite), 3 endites and a two-segmented palp (endopodite). Respiratory plate elongated, carrying more than 10 long respiratory rays (Fig. 3D). Palp with first segment carrying 3+1 apical setae; terminal segment short and broad, carrying 2 longer claws and 4 short setae (one shorter than the other). Chaetotaxy of three endites impossible to determine. Sideways directed bristles near first endite stout, one long and another short. T1 (Fig. 3H) consisting of basal part (basipodite), carrying respiratory plate (not shown), a palp (endopodite, modified to prehensile palp in males) and an endite distally set with ca. 10 setae of different morphology and length. Basal plate set with one long and stout 'b'-seta, a long and more slender 'd'-seta and one 'a'-seta. Prehensile palps (Figs 4D-E) distally hook-like and set with two, thin sub-apical setae; palps slightly asymmetrical, left prehensile palp (Fig. 4E) margin tightly rounded.
T2 (walking limb, Fig. 3G) with 4-segmented endopodite (penultimate segment divided) and elongated. First segment with short seta d1. Knee-segment devoid of seta d2. First segment of endopod elongated, with short ventro-apical seta. Second segment also with one short ventro-apical seta. Third segment with two ventro-apical setae, one short, one slightly longer. Terminal segment with one short apical and one short sub-apical seta and a long apical claw.   Fig. 3E) as typical of the family. First segment with three setae, one short medial (d1), one short subapical (d2) and one long apical (dp). Second segment without seta. Penultimate segment with one long subapical seta (g). Terminal segment carrying three setae: 2 long, one of which hirsute (h2 and h3), and one short and hirsute (h1).
Hemipenis (Fig. 4H) relatively small, with lobe a short, and with distal margin rounded, lobes b and h largely overlapping, reaching about as far as lobe a, but asymmetrially pointing towards the ventral side.
Labyrinth with first (ascending) branch long, thin and slender; post-labyrinthal spermiduct S-shaped and simple.

Description of female
Valves ( Soft parts (Fig. 5) largely as in the male, but with sexually dimorphic A2 and T1. A2 ( Fig. 5A) with setae t1-4 setae like, not transformed; z1and z3 short and slender setae, z2 longer and slender. Claws G1, G3 and GM all reaching to about the same point and claw G2 short. T1 ( Fig. 5C) with basal part as in the male and an endite distally set with ca. 13 setae of different morphology and length. Endopod a broad palp, with three unequal setae.

Measurements
See Table 3.

Etymology
The new species is named in honour of Julien Cillis (RBINS), in recognition of his continuous technical assistance with the scanning electron microscopy (SEM) images of ostracod valves at RBINS for more than 2 decades.

Type material
All type material was collected on 7 Nov. 2004 by the authors, by washing roots of floating plants (PAR 150) in a bucket and the material was filtered in a hand net with mesh size 160 µm. See Table 1 for measurements of water chemistry at time of collecting.
Allotype ♀, with soft parts dissected in glycerine in a sealed slide, and with valves stored dry in a micropalaeontological slide (MZUSP 32672).

Other material investigated
A ♂ dissected, with soft parts lost and with valves stored dry in a micropalaeontological slide (MZUSP 32681) from Baía River (PAR 195) is also deposited in the Museu de Zoologia da Universidade de São Paulo, São Paulo.

Differential diagnosis
Pseudocandona cillisi sp. nov. has valves which are much shorter and higher than those of P. geratsi and P. antilliana, while the (straight) dorsal margin is much more sloping than in P. caribbeana and P. cubensis. The new species also differs from P. annae Mehes, 1914 in the shape of the valves, which are more elongated in the latter species.

Description of male
Valves (Fig. 6A-B) small, high and short in lateral view, with greatest height situated behind the middle (and bluntly pointed there), anteriorly and posteriorly rather broadly rounded, RV and LV of highly similar shape; anterior calcified inner lamella broadly rounded, posterior calcified inner lamella narrow and narrower towards the dorsal side.
Carapace in right lateral view (Fig. 6C) showing LV overlapping RV slightly on all sides; anteriorly and posteriorly widely beyond the RV, external surface of valves smooth.
In dorsal view (Fig. 6D), carapace lancet-shaped, sharply pointed in the anteriorly, more broadly so posteriorly, greatest width situated well behind the middle.

Higuti J. & MARtENS K., Five new Candoninae species from Brazil
Carapace also in ventral view (Fig. 6E) lancet-shaped, with anterior side more acutely pointed than posterior side, in V view with slight rostrum.
Md-palp (Fig. 7C) consisting of 4 segments. Basal segment dorsally carrying the respiratory plate (not shown), ventro-apically with 2 long setae (only one hirsute = s1), the alpha seta and a short , stout and hirsute seta s2. Second segment dorso-apically with 2 setae of unequal length, ventro-basally with a short, stout and hirsute seta and ventro-apically with a group of 5 setae: 2 long setae, 2 shorter (one hirsute), and the short beta-seta. Third segment with a group of 3 smooth dorso-subapical setae of unequal length, a central group of two setae, one of which being the gamma seta, and a ventro-apical group of 2 smooth setae. Terminal segment subquadrate, chaetotaxy as in P. agostinhoi sp. nov. T1: Prehensile palps (Fig. 7F, H) distally hook-like and set with two unequal sub-apical setae; palps slightly asymmetrical, robust left prehensile palp (Fig. 7F) margin tightly rounded.
T2 (walking limb - Fig. 7B) with 4-segmented endopodite (penultimate segment divided) and elongated. First segment with short seta d1. Knee-segment devoid of seta d2. First segment of endopod elongated, with short ventro-apical seta. Second segment also with one short ventro-apical seta. Third segment with two ventro-apical setae, one short, one slightly longer. Terminal segment with one short apical and one short sub-apical seta and a long apical claw.
Caudal ramus (furca, Fig. 7D) with stout ramus and two stout apical claws. Long proximal setae, distal seta a small spine. Attachment to caudal ramus (Fig. 7E) long and stout, distally bifurcated and with 2 additional lateral branches. Length ratio ramus / largest claw = 2.0. Hemipenis (Fig. 7G) relatively small, with lobe a short and broad, distal margin only slightly rounded, lobes b and h almost completely overlapping, asymmetrically rounded and pointed towards the ventral side. Labyrinth with first (ascending) branch long, thin and slender; post-labyrinthal spermiduct S-shaped and simple.

Measurements
See Table 3. Seta h1 less than half the length (ca. 1/3) of seta h2. Caudal ramus with distal seta clearly developed, not spine-like.

Etymology
The new species is named in honour of Claudine Behen (RBINS), in recognition of her continued technical assistance with the line drawings of ostracod limbs over many years at RBINS.

Type material
All type material was collected on 4 Oct. 2012 by the authors and students, by hand net with mesh size 160 µm. See Table 1 for measurements of water chemistry at time of collecting.
Holotype ♀, with soft parts dissected in glycerine in a sealed slide, and with valves stored dry in a micropalaeontological slide (MZUSP 32682).

Type locality
BRAZIL: Matagal Stream in Upper Paraná River floodplain in sediment amongst grasses and other terrestrial vegetation in very shallow water (named littoral in Table 1). Coordinates: 22º54'26.4" S, 53º32'27.7" W.

Differential diagnosis
Pseudocandona claudinae sp. nov. can be distinguished from P. antilliana, P. caribbeana and P. cubensis by the elongated shape of the valves and the rounded dorsal margin. Pseudocandona claudinae sp. nov. appears to be closely related to P. geratsi, but the female valves of P. claudinae sp. nov. resemble those of the males in P. geratsi, while the female valves in this latter species are shorter and higher than those of the male. As no males of P. claudinae sp. nov. are known, the copulatory appendages cannot be  (2014) compared. In addition, the attachment of the caudal ramus in P. geratsi has two lateral branches, whereas there is only one in P. claudinae sp. nov.
Pseudocandona claudinae sp. nov. differs from P. annae by the more elongated valves, with a dorsal margin which is fully rounded (with a straight part in P. annae).

Description of female
Valves (Fig 8A-B) small and short, with greatest height situated behind the middle. Anteriorly and posteriorly rather broadly rounded, RV and LV of highly similar shape; anterior calcified inner lamella broadly rounded, posterior calcified inner lamella very narrow and almost disappearing towards the dorsal side.
Carapace in right lateral view (Fig. 8C) showing LV overlapping RV slightly on all sides; external surface of valves smooth. In lateral view dorsally more rounded.
Carapace in ventral view (Fig. 8E) lancet-shaped, with anterior side more acutely pointed than posterior side.
Md-palp (Fig. 9A) consisting of 4 segments. Basal segment dorsally carrying the respiratory plate (not shown), ventro-apically with 2 long setae (only one hirsute (= s1), the thin and smooth alpha seta and a short and stout hirsute seta (= s2). Second segment dorso-apically with 2 setae of unequal length, ventrobasally with a short, stout and hirsute seta and ventro-apically with a group of 5 setae: 2 long setae, 2 shorter, and the short and beta-seta. Third segment with a group of 3 dorso-subapical setae of unequal length, all smooth, a central group of two setae, one of which being the gamma seta, and a ventro-apical group of 2 setae, one long and one short, both smooth. Terminal segment subquadrate, chaetotaxy as in P. agostinhoi sp. nov. T2 (walking limb, Fig. 9C) with 4-segmented endopodite (penultimate segment divided) and elongated. First segment with short seta d1. Knee-segment devoid of seta d2. First segment of endopod elongated, with short ventro-apical seta. Second segment also with one short ventro-apical seta. Third segment with two ventro-apical setae, one short, one very long. Terminal segment with one short apical and one short sub-apical seta and a long apical claw. T3 (cleaning limb, Fig. 9E) as typical of the family. First segment with three setae, one short medial (d1), one short subapical (d2) and one long apical (dp). Second segment without seta. Penultimate segment with one long subapical seta (g). Terminal segment carrying three setae: 2 long (h2 and h3) and one very short (h1).
Caudal ramus (furca, Fig. 9D) with stout ramus and two stout apical claws. Long proximal setae, distal seta a small spine. Attachment to caudal ramus (Fig. 9B) long and stout, distally bifurcated and with additional lateral branch at ca. mid-length.

Measurements
See Table 3.

Diagnosis
Anterior calcified inner lamella broad, anterior inner margin sinuous, posterior calcified inner lamella narrow, posterior inner margin running parallel to valve margin. Terminal Md-palp segment short (L ≤ 1.5 x basal width). Prehensile palps one-segmented, base inflated, distal finger long, hook-like. Hemipenis of triangular type, without protruding lobes a and b. Caudal ramus without proximal seta, distal seta reduced to a small spine.

Remarks
As the genus was characterised by a full description of its type species, C. rochai, by Higuti & Martens (2012b), the descriptions of the following two new species are shortened.  Higuti et al., 2010: 267.

Diagnosis
A species with very elongated valves, greatest height well behind the middle; in lateral view with dorsal margin straight for more than half the total length. Anterior calcified inner lamella in both valves broad, almost ¼ of total length and with inner margin sinuous, not parallel to valve margin. Both valves externally set with elongated micro-ridges.
Prehensile palps one-segmented. Right prehensile palp set with two subequal and robust lateral setae. Left prehensile palp larger and more elongated, with hook-like distal part, distal tip slightly swollen. Hemipenis atypical of the genus, with leaf-like lobe ls, distally rounded and proximally narrowing, lobe ms broad, distally with almost straight margin, ventro-distally bluntly pointed.

Etymology
The present species is named after the very elongated carapace.

Type material
All type material was collected on 2 Feb. 2011 by JH and students, by washing roots of Eichhornia crassipes (PAR 461) in a bucket and by filtering the material in a hand net with mesh size 160 µm. See Table 1 for measurements of water chemistry at time of collecting.

Differential diagnosis
Candobrasilopsis elongata sp. nov. differs from C. rochai and C. brasiliensis by the more elongated shape of the valves, and from C. acutis sp. nov., which also has elongated valves, by the presence of external micro-ridges on the valves. Candobrasilopsis elongata sp. nov. can be distinguished from its three congeners by the atypical hemipenis, which has a lobe ls with rounded (not pointed) distal margin, and a lobe ml with almost straight distal margin (not rounded).

Description of male
Carapace in right lateral view (Fig. 10C) showing LV overlapping RV slightly on all sides. Carapace, in dorsal (Fig. 10E) and ventral views (Fig. 10F), narrow and lancet-shaped, with anterior and posterior side pointed, greatest width situated well behind the middle.
Both valves (Fig. 10A-B) very elongated, with greatest height situated behind the middle (and bluntly pointed there), anteriorly rather broadly and posteriorly rather narrowly rounded, RV and LV of highly similar shape; anterior calcified inner lamella broadly rounded, posterior calcified inner lamella very narrow and almost disappearing towards the dorsal side; inner margin of anterior calcified inner lamella slightly sinuous in both valves. External surface of both valves striated (Fig. 10D). A1, A2, Mx1, T1-3 as typical of the genus and not illustrated.
Caudal ramus (Fig. 11E) with stout ramus and two stout apical claws. Proximal setae missing, distal seta a small spine. Attachment to caudal ramus (Fig. 11D) long and stout, distally bifurcated and with additional lateral branch at ca. mid-length. Length ratio ramus / largest claw = 1.85. Hemipenis (Fig. 11F) atypical of the genus, with lobe ls leaf-like, distally rounded and proximally narrowing, lobe ms broad, distally with almost straight margin, ventro-distally bluntly pointed; an additional small ventral lobe present proximal of lobe ms. Internal labyrinth short and stout, postlabyrinthal spermiduct narrow and straight; internal copulatory process stout, beak-like and sharply pointed.

Description of female
Valves (Fig. 10G-H) and Cp (Fig. 10I-J) in lateral view similar to those in the male. Cp in D and V views (Fig. 10K-L) equally narrow and lancet-shaped, with anterior and posterior side pointed.
Soft parts as typical of the genus and, except for sexually dimorphic ones, similar to those of the male.

Measurements
See Table 3.

Diagnosis
A species with very elongated valves, greatest height well behind the middle; carapace in lateral view with weakly rounded dorsal margin, nearly straight. Anterior calcified inner lamella in both valves broad, almost 1/ 5 of total length and with inner margin sinuous, not parallel to valve margin. External valve surface smooth, devoid of ridges.
Both prehensile palps one-segmented. Right prehensile palp with distal part curved, distal tip slightly expanded, set with two subequal lateral setae. Left prehensile palp narrower and more elongated, with hook-like distal part, distal tip slightly swollen. Hemipenis with triangular and sharply pointed lobe ls.

Etymology
Named after "pointed" (Latin = acutis). The shape of lobe ls of the hemipenis is triangular and distally very pointed.

Type material
All type material was collected on 4 Oct. 2012 by the authors and students, by hand net with mesh size 160 µm. See Table 1 for measurements of water chemistry at time of collecting.
Allotype ♀, with soft parts dissected in glycerine in a sealed slide, and with valves stored dry in a micropalaeontological slide (MZUSP 32701).

Paratypes
A ♂ with soft parts dissected in glycerine in a sealed slide and with LV stored dry in a micropalaeontological slide (OC. 3359); two ♂♂ dissected and with the valves lost (MZUSP 32702, MZUSP 32703); two ♂ carapaces stored dry in micropalaeontological slides (MZUSP 32704, OC. 3358); a ♀ with soft parts dissected in glycerine in a sealed slide and with LV stored dry in a micropalaeontological slide (MZUSP 32705); a ♀ with soft parts dissected in glycerine in a sealed slide and with the valves lost (OC. 3361); three ♀ carapaces stored dry in micropalaeontological slides (MZUSP 32706, MZUSP 32707, OC. 3360).

Type locality
BRAZIL: Matagal Stream in Upper Paraná River floodplain in sediment amongst grasses and other terrestrial vegetation in very shallow water (named littoral in Table 1). Coordinates: 22º54'26.4" S, 53º32'27.7" W.

Differential diagnosis
Candobrasilopsis acutis sp. nov. is characterized by the shape of both prehensile palps and especially by the very pointed lateral shield of the hemipenis, by which it can easily be distinguished from the other three species in the genus. The shape of the valves of C. acutis sp. nov. is quite similar to those of C. elongata sp. nov., but C. acutis sp. nov. lacks the clear external striation of the latter species (compare Figs 10D, J with 12D, H).

Description of male
Carapace very elongated in right lateral view (Fig. 12C), with greatest height situated behind the middle, anteriorly and posteriorly broadly rounded; LV overlapping RV slightly on all sides; external surface of valves smooth (Fig. 12D). In dorsal view (Fig. 12E) and ventral view (Fig. 12F) carapace lancet-shaped, sharply pointed anteriorly, more broadly so posteriorly.
Caudal ramus (furca, Fig. 13D) with stout ramus and two stout apical claws. Proximal setae missing, distal seta a small (hirsute) spine. Attachment to caudal ramus (Fig. 13E) long and stout, distally bifurcated and with additional lateral branch at ca. mid-length. Length ratio ramus / largest claw = 1.84. Hemipenis (Fig. 13C) typical of the genus, with small and rounded ms and very pointed, triangular ls.

Description of female
Valves (Fig. 12A-B) very elongated, with greatest height situated behind the middle, anteriorly and posteriorly broadly rounded; RV and LV of highly similar shape; anterior calcified inner lamella broadly rounded, posterior calcified inner lamella very narrow and almost disappearing towards the dorsal side; inner margin of anterior calcified inner lamella slightly sinuous in both valves. Soft parts as typical of the genus and, except for sexually dimorphic ones, similar to those of the male.

Measurements
See Table 3.

Taxonomy of Pseudocandona and Typhlocypris
Vejdovsky (1882) erected Typhlocypris as a subgenus of Cypris to accommodate the distinct species Cypris eremita Vejdovsky, 1880, while Kaufmann (1900 established the genus Pseudocandona for the species Candona pubescens Koch, 1837. For historical reasons, the species Cypris eremita was transferred to Pseudocandona and Typhlocypris became an unused senior synonym (Danielopol 1978;Meisch 2000). Karanovic (2005) synonymised the whole of Pseudocandona with the older taxon Typhlocypris, simply because the older name has priority over the more recent name following the ICZN. Whereas this was technically correct, the name Pseudocandona was so well-used at that stage that this move was not in the interest of nomenclatorial stability. For some time, this created an uneasy and confusing situation. Meisch (2000) foreshadowed a solution, by suggesting that the eremita-group of Pseudocandona has a clearly distinct morphology, sufficient to consider it a genus separate from Pseudocandona. Namiotko et al. (2014) meanwhile have indeed reinstated Typhlocypris as a separate genus for the eremita-lineage, while Danielopol et al. (2012) have created the genus Marmocandona for the zschokkeispecies group in Pseudocandona. We follow this position and maintain all other species groups for the time being within Pseudocandona, although, as foreshadowed by Danielopol (1978), at least the Pseudocandona species of the Siberian Lake Baikal will eventually have to be transferred to a new genus.
For a full discussion on the taxonomic and nomenclatorial history of Typhlocypris and Pseudocandona, see Namiotko et al. (2014).

Higuti J. & MARtENS K., Five new Candoninae species from Brazil
Taxonomic position of Candona annae Mehes, 1914Broodbakker (1983 described four species in the genus Pseudocandona from the West Indies and also transferred the Columbian species Candona annae Mehes, 1914 to this genus, albeit implicitly. Mehes (1914, fig. 10d) had indeed illustrated four long setae (small beta setae not drawn) on the second segment of the Md-palp, which falls within the diagnosis of this genus. Furtos (1936) provided excellent illustrations of a single male specimen from Florida that she referred to this species, but which had a fairly different lobe "a" on the hemipenis and with the second segment of the Rpp being almost evenly rounded. Furtos (1935) described P. annae var septentrionalis from Massachusetts, mainly differing from the Florida specimen by the presence of a distal seta on the caudal ramus and the absence of a fused zone in the valves. Valve shape, and shape of hemipenis and of the prehensile palps are similar in both forms described by Furtos.
According to Broodbakker (1983), the specimen reported by Furtos (1936) from Florida was in fact not P. annae, but a different species, possibly closely related to either his P. geratisi, or more likely P. antilliana. Later on in the same paper, he wrote that the Florida male of Furtos (1936) could very well belong to P. antilliana. Broodbakker further mentioned that also P. elliptica (Furtos, 1933) from Ohio is closely related to P. antilliana. Broodbakker did not comment on the position of P. annae septentrionalis (Furtos, 1935). Karanovic (2006) transferred P. annae to the re-instated genus Typhlocypris Vejdovsky, 1882. Karanovic (2005 explicitly transferred P. geratsi Broodbakker (1983) to Typhlocypris, while Karanovic & Datry (2009) also moved P. caribbeana Broodbakker, 1983 to Typhlocypris, but did not mention the position of the other Pseudocandona species described by Broodbakker (1983) in their list of South and Central American candonids. As outlined above, Typhlocypris now only comprises the old 'P. eremita' group, so none of the South and Central American species belong to this genus. Karanovic (2006) provided a redescription of P. a. septentrionalis, based on one of the original dissections of a male by Furtos, and synonymised it with P. annae s.s. At the same time, Karanovic (loc.cit.) also sank P. antilliana Broodbakker, 1983 into the synonymy of P. annae. Strangely enough, the caudal ramus, originally illustrated by Furtos (1935) with a clear distal seta, one of the major characters of this form, lacks this seta in the illustration by Karanovic (2006).
Finally, Karanovic (2005) illustrated P. cf. geratsi (in Typhlocypris, sic) from interstitial waters near Perth, Western Australia, but also illustrated some aspects of the morphology of the holotype of P. geratsi Broodbakker, 1983, including a hemipenis in erection, not illustrated by Broodbakker (loc.cit.). Such a wide distribution for a candonid species would be highly unusual, though of course not impossible.
In conclusion, we here maintain P. annae and P. antillana as separate species, with the male from Florida most likely belonging to the latter species. The positions of P. annae septentrionalis (Furtos, 1935) and of the Australian species P. cf. geratsi remain uncertain.

Taxonomic position of the presently described Pseudocandona species
With the eremita-group now back in Typhlocypris and the zschokkei-group allocated to Marmocandona, Pseudocandona now comprises species from the compressa-, rostrata-, prespica-and the caribbeanagroups (according to Namiotko & Danielopol 2004), together with the Lake Baikal species flock. Namiotko & Danielopol (2004) allocated P. caribbeana and P. cubensis to a separate species group (the caribbeana-group), but P. antilliana and P. geratsi to the rostrata-group within the genus. Nevertheless, both P. geratsi and P. antilliana have 4 ventral setae (plus beta-seta) on the second segment of the Mdpalp, and thus belong with P. caribbeana and P. cubensis to the same species group, which is not the rostrata-group of which the species have 3 setae plus the beta seta there. Namiotko & Danielopol (2004, European Journal of Taxonomy 106: 1-36 (2014 table 2) provided an alternative set of characters to distinguish between the different species groups in Pseudocandona, namely by looking at the length of claws on the A2, relative to the combined lengths of the second and third segments of the endopod. Also here, the new species fall well into the range of the species of the caribbeana-group (including P. geratsi and P. antiliana). For example, the ratio G1 / E2+3 in females is 1.6-1.9 for the caribbeana-group, and 1.68 for P. agostinhoi sp. nov.; the ratio GM / E2+3 in females is 1.3-1.5 for the caribbeana-group and 1.38 for P. agostinhoi sp. nov.
One potential pitfall in interpreting the illustrations of Broodbakker (1983) is the use of different nomenclature for the claws and setae on the A2. Martens (1987) demonstrated that, in the sexual dimorphism in A2-chaetotaxy, form and shape of the claws and setae can change dramatically, but relatively position does not. The work by Broodbakker (1983) predates this finding, and thus setae and claws were named based on appearance, not on relative position. Table 4 corrects this situation and homologizes Broodbakker's nomenclature with the modern one. In doing so, the close relationship between our and Broodbakker's species becomes even more clear.
There are some small differences that need further investigation. For example, the reduced seta s2 on the Md-palp is ca. twice as long in P. antilliana as in P. agostinhoi sp. nov., while the seta z1 in the female is illustrated as a short claw in P. antilliana (Broodbakker 1983, fig. 4D), which would be unusual in females.
In all, however, the three new species here allocated to Pseudocandona appear to belong in one lineage with the four species described by Broodbakker (1983), which, following Namiotko & Danielopol (2004), we here continue to name the caribbeana-group.  Table 4. Re-appraisal of the homology of claws and setae on two species in the P. caribbeana group, based on Broodbakker (1983) and Martens (1987), NA = not applicable.

Higuti J. & MARtENS K., Five new Candoninae species from Brazil
From a zoogeographical point of view, uniting these seven species into one lineage, and maybe including also others like P. annae, seems logical.

Ecology
The five new species of candonids were found in 23 localities in the alluvial valley of the Upper Paraná River. The most common species of the five newly described here is Candobrasilopsis elongata sp. nov., which was recorded from 16 localities; Pseudocandona agostinhoi sp. nov. was found in nine localities, P. cillisi sp. nov. in six, and C. acutis sp. nov. and P. claudinae sp. nov. were only recorded in one, and the same, locality.
The latter two new species were found in sediments (named littoral in Table 1) of the Matagal stream, with pH 6.2, a low value of dissolved oxygen (1.73 mg L -1 ) and a high value of electrical conductivity (179.9 µS cm -1 ). At the time of collecting, the surface water available was less than 1m 2 , and only a few mm of standing water hidden by many grasses could be sampled.
Candobrasilopsis elongata sp. nov., was recorded in localities with pH values ranging between 4.7 and 7.2, electrical conductivity between 25.8 and 49.6 µS cm -1 and dissolved oxygen between 0.14 and 8.3 mg L -1 . The predominant type of substrate in which this species was found was Eichhornia crassipes.
Pseudocandona agostinhoi sp. nov. occurred in both types of substrate, namely littoral and Eichhornia crassipes, with pH values ranging between 5.4 and 6.9, electrical conductivity between 28.1 and 64.1 µS cm -1 and dissolved oxygen between 0.9 and 7.2 mg L -1 . Finally, P. cillisi sp. nov. was found in environments with pH values ranging between 4.9 and 6.1, electrical conductivity between 27.0 and 41.8 µS cm -1 and low values of dissolved oxygen, between 1.0 and 4.5 mg L -1 . Also this species was predominant in Eichhornia crassipes.