On Paranacypris samambaiensis gen. nov., sp. nov. (Crustacea, Ostracoda), the first South American psychrodromid from the alluvial valley of the Upper Paraná River, Brazil Author Higuti, Janet Author Meisch, Claude Author Martens, Koen text Journal of Natural History 2009 2009-04-30 43 13 - 14 769 783 http://dx.doi.org/10.1080/00222930802702506 journal article 10.1080/00222930802702506 1464-5262 5216121 Paranacypris samambaiensis gen. nov., sp. nov. ( Figures 2–4 ) Type locality Lake Samambaia 2, a closed lake in the Taquaruçu system ( Mato Grosso do Sul State ). Two samples were taken during the sampling campaigns in 2004 (see Table 1 ) . Type material From type locality . Holotype : a dissected female (MZUSP 19289), with soft parts dissected in glycerine in a sealed slide, and valves stored dry in a micropalaeontological slide. Two paratype females, dissected, one (OC.3071) stored as the holotype , the other (MZUSP 19291) only consists of soft parts in a sealed slide, valves are lost. Three paratype females (OC.3072-3074) in toto , only LV and RV (OC.3075), used for scanning electron microscopy and stored dry in micropalaeontological slides. Three in toto paratype females in 70% ethanol (MZUSP 19292). From Lake Figueira (see Table 1 ) . One paratype female dissected and stored as the holotype (MZUSP 19290), but with one valve lost. The material is deposited as follows: all OC-numbers are stored in the Ostracod Collection of the Royal Belgian Institute of Natural Sciences (Brussels), the MZUSP numbers are in the Museu de Zoologia da Universidade de São Paulo , Brazil . See Table 1 for an overview of other localities where this new genus and species was found: Lake Samambaia 1, Lake Walter 1, Walter 2 and Lake Pousada. This material was not used for the present description, these specimens are therefore not paratypes . Derivation of name The specific name refers to the type locality, Lake Samambaia . Diagnosis Valves elongated, laterally flattened, LV anteriorly with incomplete inner list, RV anteriorly with submarginal inner list and pronounced posterior selvage, externally with anterior sulcus. LV widely overlapping RV anteriorly. A1 with medium-sized, one-segmented Rome organ and small Wouters’ organ. A2 with natatory setae reaching well beyond tip of claws. Mx1 with five ‘‘reversed’’ setae on respiratory plate, Zahnborsten on third endite smooth. T1 with e-seta short, stout and hirsute. Caudal ramus and attachment stout and strong. Additional description of female Valves in lateral view ( Figure 2A–C ) elongated, with anterior margin more broadly rounded than the posterior one; greatest height situated almost in the middle; LV largely overlapping RV anteriorly, and to a lesser degree ventrally. RV in internal view with anterior inner list ( Figure 2J ) and posteriorly with a clearly inwardly displaced selvage ( Figure 2K ). LV in interior view with dorsal and ventral remnants of an anterior inner list ( Figure 2H ), posteriorly without special structures ( Figure 2I ). In both valves anterior calcified inner lamella wide, posterior one narrow. RV externally with a sulcus close to the anterior margin. LV with external list running almost parallel to the ventral valve margin. Figure 2. Valves of Paranacypris samambaiensis gen. nov., sp. nov. (A) LV, internal view (OC.3075). (B) RV, internal view (OC.3075). (C) Cp, right lateral view (OC.3073). (D) Cp, dorsal view (OC.3074). (E) Cp, ventral view (OC.3072). (F) Cp, dorsal view (OC.3074), detail of anterior part. (G) Cp, dorsal view (OC.3074), detail of posterior part. (H) LV, internal view (OC.3075), detail of anterior part. (I) LV, internal view (OC.3075), detail of posterior part. (J) RV, internal view (OC.3075), detail of anterior part. (K) RV, internal view (OC.3075), detail of posterior part. Scale bars: A–E, 200 mm; F, G, 50 mm; H–K, 100 mm. Figure 3. Limbs of Paranacypris samambaiensis gen. nov., sp. nov. (A) Md coxal plate (MZUSP 19291). (B) A1 (MZUSP 19289). (C) A2 (MZUSP 19291). (D) attachment of the caudal ramus (MZUSP 19289). (E) Caudal ramus (MZUSP 19289). (F) Md palp (MZUSP 19291). Scale bars: B, 73 mm; D, E, 67 mm; F, 58 mm; and A, C, 30 mm. Figure 4. Limbs of Paranacypris samambaiensis gen. nov., sp. nov. (A) T3 (OC.3071). (B) T3, detail of pincer (OC.3071). (C) T1 (MZUSP 19289). (D) T2 (MZUSP 19289). (E) Mx1, detail of palp (MZUSP 19291). (F) Mx1, detail of third endite (MZUSP 19291). (G) Mx1 (MZUSP 19291). (H) Mx1, respiratory plate (MZUSP 19290). Scale bars: D, 67 mm; A, 58 mm; C, G, 40 mm; F, 13 mm; and B, E, H, 8 mm. Table 1. Localities from which Paranacypris samambaiensis gen. nov., sp. nov. was collected.

Sample	Data	Locality name	S °	S9	S0	W °	W9	W0	System	Substrate	WT ( ° C) EC (mS cm21)		pH	DO (mg l21)
PAR 39	15.03.04	Lake Figueira	22	45	31.0	53	15	36.0	PAR	Littoral	29.7	123.8	6.1	4.3
PAR 102	04.07.04	Lake Samambaia 1	22	36	16.0	53	22	33.0	TAQ	Floating	25.4	29.2	6.5	8.3
PAR 103	04.07.04	Lake Samambaia 1	22	36	16.0	53	22	33.0	TAQ	Littoral	25.4	29.2	6.5	8.3
PAR 105	04.07.04	Lake Samambaia 2	22	35	48.0	53	22	18.0	TAQ	Littoral	26.7	48.3	7.6	10.4
PAR 107	05.07.04	Lake Walter 1	22	34	59.0	53	21	52.0	TAQ	Littoral	23.5	49.6	5.7	12.0
PAR 173	08.11.04	Lake Pousada	22	44	43.5	53	14	7.3	PAR	Littoral	26.2	71.1	5.6	3.5
PAR 239	12.11.04	Lake Samambaia 1	22	36	15.3	53	22	32.9	TAQ	Salvinia spp.	24.2	30.9	6.3	8.5
PAR 241	12.11.04	Lake Samambaia 1	22	36	15.3	53	22	32.9	TAQ	Littoral	25.8	31.8	5.9	8.5
PAR 244	12.11.04	Lake Samambaia 2	22	35	39.3	53	22	28.3	TAQ	littoral	25.1	47.5	7.1	9.5
PAR 248	12.11.04	Lake Walter 2	22	34	53.3	53	21	51.9	TAQ	floating	29.1	16.9	5.5	8.6
PAR 249	12.11.04	Lake Walter 2	22	34	53.3	53	21	51.9	TAQ	Pistia	29.1	16.9	5.5	8.6
stratiotes
PAR 250	12.11.04	Lake Walter 1	22	34	58.3	53	21	50.9	TAQ	Littoral	28.6	40.9	6.0	8.4

Samples in bold are from the type locality. TAQ, Taquaruçu; PAR, Paraná; floating, mixed floating plants; WT, water temperature; EC, electrical conductivity are from closed lakes. Cp in dorsal view ( Figure 2D ) with greatest width (about one-third of the length) situated in the middle; anterior overlap LV/RV pronounced ( Figure 2F ); posteriorly with both valves almost equal ( Figure 2G ). Cp in ventral view ( Figure 2E ) with LV overlapping RV along the entire length. External valve surface set with large pores ( Figure 2F,G ). A1 ( Figure 3B ) with seven segments. First segment with two ventral setae and one dorsal seta; Wouters’ organ small. Second segment with one mediodorsal seta; Rome organ of medium size, about half the height of the segment. Third segment more than twice as long as wide, with one shorter ventral and one longer dorsal seta. Fourth segment almost as long as wide, with two long ventral setae and two even longer dorsal natatory setae. Fifth segment slightly longer than wide, also with two long ventral and two longer dorsal natatory setae. Sixth segment about 1.5 times as long as wide, with four long and one short natatory setae. Terminal (seventh) segment about 1.5 times as long as wide, with one shorter seta, one even shorter aesthetasc Ya and two long natatory setae. A2 ( Figure 3C ) with exopodite reduced to a small plate, bearing one long and two short setae. Endopodite three-segmented. First segment elongated and stout, aesthetasc Y long and slender (about one-third of length of segment). Five natatory setae reaching well beyond the tips of the end claws; accompanying (sixth) seta just reaching beyond the tip of the second segment. Second segment with two dorsolateral and four ventrolateral setae (t1–4) plus aesthetasc y1; distal chaetotaxy typical of female Cyprididae , with three z-setae and three G-claws, claws G1 and G3 relatively long and slender, claw G2 about half the length of the other two claws, one apical aesthetasc y2. Terminal (third) segment with large claw GM, shorter claw Gm, seta g and short aesthetasc (y3) fused with a seta, the latter longer than the aesthetasc. Md ( Figure 3A,F ) with coxal plate distally set with rows of spines and small setae. Palp with a- seta rather long, slender and smooth, b- seta short, stout and hirsute, c- seta large, broad and hirsute in distal two-thirds of its length. First segment with two long barbed setae, one long smooth seta and the alpha seta. Second segment dorsally with a group of three smooth setae, ventrally with three long and smooth and one shorter and hirsute setae as well as the b- seta. Third segment dorsally with four subapical and subequal setae, ventrally with one subapical seta and a short aesthetasc, medially with four setae (three plus c- seta). Terminal segment with three slender claws and three long setae. Mx1 ( Figure 4E–G ) with second palp-segment distinctly spatulate, Zahnborsten on third endite smooth. Sideways directed bristles short and smooth. Respiratory plate large and elongate, distally with a row of ca. 18 ‘‘normal’’ rays and five ‘‘reversed’’ rays. T1 ( Figure 4C ) with two a- setae, one b- seta and one d- setae, all of normal shape. One e-seta short, stout and hirsute. Distal chaetotaxy of coxal plate consisting of 16 setae of sometimes very different shape and length. T2 ( Figure 4D ) with elongated segments and relatively long setae and end claw. First segment with seta d1 long, reaching beyond second segment, this (knee-) segment with seta d2 missing. Third segment with one long ventroapical seta, reaching almost to segment 5. Fourth segment divided into two elongated subsegments: 4a with a ventroapical seta, not reaching tip of segment 4b, this segment with 2 ventroapical setae, one about twice as long as the other. Fifth segment with one subapical seta and one apical seta and one long, thin apical claw. T3 ( Figure 4A,B ) a cleaning limb. First segment with three setae. Second segment with one long apical seta. Third segment with one short lateral seta. Distal part of third segment and fourth segment fused to a pincer-shaped organ, bearing one long seta, one seta of medium length, two rows of setulae and one comb-like seta. Caudal ramus ( Figure 3E ) distally with two claws, one claw-like posterior seta and one apical seta. Attachment ( Figure 3D ) with simple distal bifurcation and triangular structure at basis (typical of Herpetocypridinae ). Males unknown. Measurements OC.3075: LV: length 5825 mm , height 5364 mm ; RV: length 5788 mm , height 5354 mm ; OC.3073: length 5806 mm , height 5354 mm . Remarks It is at present difficult to distinguish between generic and specific characters because only one species is known in this genus and because males are unknown. Male copulatory appendages and prehensile palps generally offer the best features to distinguish between species. Ecology The species has been found in 12 of more than 132 samples in 48 localities; four of these samples were pleuston, eight were fully benthic. All localities were in closed lakes (i.e. not connected to the main channels of the Paraná floodplain), none in open lakes or in channels. The pH ranged between 5.5 and 7.6, electrical conductivity between 16.9 and 123.8 mS cm 21 and dissolved oxygen between 3.5 and 12 mg l 21 . The species was found all year around ( Table 1 ). Key to the genera of the Herpetocypridinae The present key builds on characters identified in the generic diagnoses by Martens (2001) , but because of the increased evidence for mosaic evolution (see below), the tribes introduced by Martens (2001) are not used to key out genera. 1 (8) Maxillular (Mx1) palp: terminal segment spatulate. Caudal rami symmetrically built, posterior seta always present, sometimes claw-like....... 2 2 (3) Cleaning leg (3rd thoracopod): penultimate segment at around mid-length with 2 (long) setae (NB: the terminal segment is tiny, barely visible in all Cyprididae ).................................. Candonocypris 3 (2) Cleaning leg: penultimate segment at around mid-length with one (long) seta................................................. 4 4 (5) Caudal ramus: posterior seta untransformed (a true seta). Length51.5– 2.5 mm ..................................... Herpetocypris 5 (4) Caudal ramus: posterior seta transformed, claw-like. Length50.7– 1.5 mm .................................................... 6 6 (7) Walking leg (2nd thoracopod): setae d1 and d2 subequal in length. Length>1.0 mm................................. Ilyodromus 7 (6) Walking leg: d1 long, d2 absent. Length, 1 mm ................................ Paranacypris gen. nov. (here described, one species) 8 (1) Mx1 palp: terminal segment rectangular, not spatulate. Caudal rami symmetrical or asymmetrical; posterior seta present or absent, when present, claw-like or not................................... 9 9 (12) Caudal rami conspicuously asymmetrical..................... 10 10 (11) Marginal valve zones with conspicuous septa........... Stenocypris 11 (10) These septa always missing............................................... Chrissia 5 Gesa Hartmann 5 Parastenocypris Hartmann 12 (9) Caudal rami symmetrical or slightly asymmetrical............... 13 13 (14) Left valve with a conspicuous posteroventral spine......... Acocypris 14 (13) Left valve without that spine.............................. 15 15 (18) Caudal ramus: posterior seta long.......................... 16 16 (17) Posterior inner valve margin conspicuously curved........ Stenocypria 17 (16) Posterior inner valve margin regularly rounded.................................................... Ampullacypris (one species) 18 (15) Caudal ramus: posterior seta short and claw-like or absent......... 19 19 (20) Caudal ramus: posterior seta a conspicuous claw or claw-like seta. Walking leg: setae d1 and d2 subequal in length.............. Psychrodromus 20 (19) Caudal ramus: posterior seta either an inconspicuous spinule or absent. Walking leg: d1 two to four times longer than d2............... 21 21 (22) Caudal ramus: posterior seta an inconspicuous spinule or absent. Carapace 1.0–2.0 mm long. Males present or missing. Hemipenis with conspicuous, sclerotized hook-like apical structure on medial shield; post-labyrinthal spermiduct with two to four additional circular whorls... Humphcypris 22 (21) Caudal ramus: posterior seta absent. Carapace ca. 1.0 mm long. Males always present. Hemipenis without hook-like apical structure on medial shield; post-labyrinthal spermiduct with up to six additional circular whorls.................................. Somalicypris (one species)