Pseudocandona agostinhoi, Higuti & Martens, 2014

Higuti, Janet & Martens, Koen, 2014, Five new species of Candoninae (Crustacea, Ostracoda) from the alluvial valley of the Upper Paraná River (Brazil, South America), European Journal of Taxonomy 106, pp. 1-36 : 8-16

Pseudocandona agostinhoi sp. nov.

urn:lsid:zoobank.org:act:479455A1-91AD-4866-AADB-B8D6EB3892B1

Figs 2–5

“ Candona ” sp. 4 nov. sp. Higuti et al., 2007: 1935.

“ Candona ” sp. 2 n. sp. Higuti et al., 2009c: 664.

“ Candona ” sp. 2 n. sp. Higuti et al., 2010: 267.

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 ).

Allotype

♀, dissected and stored like the holotype ( MZUSP 32654 ).

Paratypes

8 ♂♂ dissected and stored like the holotype ( MZUSP 32655, MZUSP 32656, MZUSP 32657, MZUSP 32658, MZUSP 32659, OC.3302, OC.3306, OC.3307); three ♂ carapaces stored dry in micropalaeontological slides ( MZUSP 32660, MZUSP 32661, OC.3304); eight ♀♀ dissected and stored like the holotype ( MZUSP 32662, MZUSP 32663, MZUSP 32664, MZUSP 32665, MZUSP 32666, OC.3303, OC.3308, OC.3309); three ♀ carapaces stored dry in micropalaeontological slides ( MZUSP 32667, MZUSP 32668, OC.3305).

Other material investigated

A ♂ ( MZUSP 32669) and a ♀ ( MZUSP 32670) carapace stored dry in micropalaeontological slides from Ventura Lake ( PAR 1) and Pintado Lake ( PAR 213), respectively, are also deposited in the Museu de Zoologia da Universidade de São Paulo, São Paulo.

Type locality

BRAZIL: Peroba Lake in Upper Paraná River floodplain in roots of the floating plant species Eichhornia crassipes . Coordinates: 22º54’39.4” S, 53º38’34.5” W.

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 and P. 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 .

Description of male

Carapace in right lateral view ( Fig. 2C ) rather elongated, showing LV overlapping RV on all sides, with larger overlap at both anterior and posterior extremities, external surface of valves smooth. Cp in dorsal and ventral views ( Fig. 2D–E ) lancet-shaped, sharply pointed anteriorly, more broadly so posteriorly, greatest width situated slightly behind the middle.

Valves ( Fig. 2A–B ) with greatest height situated behind the middle (and with a blunt angle there), posteriorly rather broadly rounded, anteriorly less so. RV and LV of similar shape; anterior calcified inner lamella more broadly rounded than posterior calcified inner lamella. LV with anterior and posterior inner lists, situated closely to valve margin, yet clearly separated from it.

A1 ( Fig. 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.

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.

T3 (cleaning limb, 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).

Caudal ramus (= furca, Fig. 4F ) with stout ramus and two stout apical claws. Long proximal setae, distal seta a small spine. Attachhment to caudal ramus ( Fig. 4G ) long and stout, distally bifurcated and with additional lateral branch at ca. mid-length. Length ratio ramus / largest claw = 1.92.

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.

Zenker organ ( Fig. 4C ) short and broad, with at least 5 spinous whorls.

Description of female

Valves ( Fig. 2F–G ) similar to those in the male; Cp ( Fig. 2H ) in lateral view with bigger overlap at the anterior extremity; Cp in D and V views ( Figs 2I–J ) equally narrow and lancet-shaped, in V view highlighting the overlap.

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.

Caudal ramus ( Fig. 5B ) with stout ramus and two stout apical claws. Long proximal setae, distal seta a small spine. Length ratio ramus / largest claw = 1.79.

Measurements

See Table 3 .

Figures

Fig. 2. Valves of Pseudocandona agostinhoi sp. nov. A–E ♂ and F–J ♀. A, F. LV, internal view (A = MZUSP 32655, F = OC. 3303). B, G. RV, internal view (B = MZUSP 32655, G = OC. 3303). C, H. Cp, right lateral view (C = MZUSP 32660, H = MZUSP 32667). D, I. Cp, dorsal view (D =MZUSP 32661, I = MZUSP 32668). E, J. Cp, ventral view (E = OC. 3304, J = OC. 3305). Scale bars: A–J = 500 µm.

Fig. 3. Limbs of Pseudocandona agostinhoi sp. nov. (♂). A. A2 (MZUSP 32656). B. A2, detail of the last segment (MZUSP 32656). C. A1 (OC. 3302). D. Mx1, respiratory plate (OC. 3302). E. T3 (MZUSP 32655). F. Md, coxal plate (MZUSP 32653). G. T2 (MZUSP 32653). H. T1 (MZUSP 32653). Scale bars: A–H = 50 µm

Fig. 4. Limbs of Pseudocandona agostinhoi sp. nov. (♂). A. Mx1 (MZUSP 32653). B. Md palp (MZUSP 32655). C. Zenker organ (MZUSP 32653). D. Right prehensile palp (MZUSP 32653). E. Left prehensile palp (MZUSP 32653). F. Caudal ramus (MZUSP 32653). G. Attachment of the caudal ramus (MZUSP 32653). H. Hemipenis (MZUSP 32653). Scale bars: A–H = 50 µm.

Fig. 5. Limbs of Pseudocandona agostinhoi sp. nov. (♀). A. A2, detail of the last segments (MZUSP 32654). B. Caudal ramus (MZUSP 32654). C. T1 (MZUSP 32654). Scale bars: A–C = 50 µm.