Candobrasilopsis acutis, 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 : 28-31

Candobrasilopsis acutis sp. nov.

urn:lsid:zoobank.org:act:2894DAF9-9CF7-4A60-B25F-6ED4BFEF8E09

Figs 12–13

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.

Holotype

♂ carapace stored dry in a micropalaeontological slide ( MZUSP 32700 ).

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.

Internal valve anatomy as in the female (see below).

A1, A2, Mx1, T1-3 as typical of the genus and not illustrated. Md-palp ( Fig. 13F ) consisting of 4 segments, terminal segment short (L ≤ 1.5 x basal width).

Prehensile palps ( Fig. 13A–B ) both segmented, distally hook-like and set with two unequal, sub-apical setae; palps slightly asymmetrical, right prehensile palp ( Fig. 13A ) basally slightly more swollen and with distal hook-like expansion apically swollen.

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.

Carapace in right lateral ( Fig. 12G ), dorsal ( Fig. 12I ) and ventral views ( Fig. 12J ) similar to those in the male.

Soft parts as typical of the genus and, except for sexually dimorphic ones, similar to those of the male.

Measurements

See Table 3 .

Figures

Fig. 12. Valves of Candobrasilopsis acutis sp. nov. C–F ♂ and A–B, G–J ♀. A. LV, internal view. (MZUSP 32701) B. RV, internal view (MZUSP 32701). C, G. Cp, right lateral view (C = MZUSP 32700, G = MZUSP 32706). D, H. Cp, right lateral view, detail (D = MZUSP 32700, H = MZUSP 32706). E, I. Cp, dorsal view (E = MZUSP 32704, I = MZUSP 32707). F, J. Cp, ventral view (F = OC. 3358, J = OC. 3360). Scale bars: A–C, E–G, I–J = 500 µm; D, H = 20 µm.

Fig. 13. Limbs of Candobrasilopsis acutis sp. nov. (♂). A. Right prehensile palp (MZUSP 32703). B. Left prehensile palp (MZUSP 32703). C. Hemipenis (MZUSP 32703). D. Caudal ramus (MZUSP 32703). E. Attachment of the caudal ramus (MZUSP 32703). F. Md palp (MZUSP 32703). Scale bars: A–F = 50 µm.

Fig. 10. Valves of Candobrasilopsis elongata sp. nov. A–F ♂ and G–L ♀. A, G. LV, internal view (A = MZUSP 32687, G = MZUSP 32686). B, H. RV, internal view (B = MZUSP 32687, H = MZUSP 32686). C, I. Cp, right lateral view (C = MZUSP 32690, I = MZUSP 32699). D, J. Cp, right lateral view detail (D = MZUSP 32690, J = MZUSP 32699). E, K. Cp, dorsal view (E = MZUSP 32692, K = MZUSP 32696). F, L. Cp, ventral view (F = MZUSP 32691, L = MZUSP 32697). Scale bars: A–C, E–I, K–L = 500 µm; D, J = 20 µm.