Cabelodopsis hispida ( Sars, 1901 ) Sars, 1901

Higuti, Janet & Martens, Koen, 2012, On a new cypridopsine genus (Crustacea, Ostracoda, Cyprididae) from the Upper Paraná River Floodplain (Brazil), Zootaxa 3391, pp. 23-38 : 30-34

Cabelodopsis hispida ( Sars, 1901) n. comb.

( Figures 2 –5)

Synonymies

1901 Cypridopsella hispida n. sp. — Sars, pp 42-43, Pl VIII, figs 15, 16. 1940 Zonocypris hispida ( Sars, 1901) — Klie, pp 60-61, figs 1, 2. 2007 Bradleystrandesia hispida ( Sars, 1901) — Higuti et al.: 1932. 2009c “ Cypridopsis ” n. gen. 2 hispida — Higuti et al.: 64. 2010 “ Cypridopsis ” n. gen. 2 hispida — Higuti et al.: 267. 2010 “ Cypridopsis ” n. gen. 2 hispida — Mormul et al.: 189.

Type locality and type material. Sars (1901) had only a few female specimens, which he raised from dried mud, collected near Itatiba (São Paulo State). These specimens are still in the collections of the Natural History Museum of Oslo (1– 2 specimens in EtOH in a large jar nr 53.3 and slide 11535 in folder 496; P. DeDeckker, pers. comm.).

Diagnosis: It is at present difficult to distinguish between generic and specific characters, because only one species is thus far known in this genus and because males are unknown. Male copulatory appendages and prehensile palps generally offer the best features to distinguish between species. At this stage, we consider the elongated shape of the carapace, with greatest height situated in front of the middle, and the hirsute aspect of it to be specific characters.

‘Zonocypris’ inornata Klie, 1936 from Cameroon is quite similar in appearance (subtriangular valves, hirsute, no additional valve ornamentation), but whereas in Cabelodopsis hispida n. gen. the LV overlaps the RV anteriorly, this is the inverse in ‘Z.’ inornata.

Remarks: Sars (1901) described this species, in an incomplete way, in the genus Cypridopsella Kaufmann, 1900 . Klie (1940) transferred it to Zonocypris , to which indeed it bears some resemblance. However, detailed analysis of the anatomy of this species shows that it belongs to a lineage related to, yet different from, Zonocypris . It is here lodged in a new genus.

Additional description of female. Cp hirsute, entirely covered with strong setae, but valves smooth. Cp in lateral view ( Figure 2 G) oval triangular in form, greatest H somewhat exceeding half the L, and situated slightly in front of the middle, dorsal margin sloping towards the front, rather straight towards the posterior side, ventral margin straight to slightly convex, both extremities rounded, the anterior one somewhat more broadly than the posterior one.

Cp in dorsal ( Figure 2 I) and ventral view ( Figure 2 J) oblong ovate in form; greatest width (about half of the length) situated in the middle; LV overlapping RV in both extremities and along the ventral margin. Both valves with a strong ventral outer list.

Both valves in internal view with relatively wide anterior and narrow posterior calcified inner lamella. Muscle scars with the typical cypridopsine pattern.

LV in interior view with antero-ventral remnants of an inner list ( Figure 2 A, B), this list continuing along the ventral side and posteriorly developing in a widely inwardly displaced and double inner list; postero-dorsally without hinge-like structures ( Figure 2 A, C).

RV in internal view with antero-ventral remnants of an inner list ( Figure 2 D, E), this list continuing along the ventral side and posteriorly developing in a strong and double, but submarginal inner list, postero-ventrally with a wide flange, caused by a strong selvage ( Figure 2 F, H), the latter carrying 4–5 small tubercles, the latter only visible with scanning electron microscopy (SEM) and with the valve tilted ( Figure 2 H).

A1 ( Figure 3 E) with 7 segments. First segment with 2 long ventral setae, and one dorsal seta. Second segment with one short dorsal seta. Third segment ca. 1.5 times as long as wide, with one shorter ventral and one longer dorsal seta. Fourth segment almost as long as wide, with 1 short ventral setae and 2 long dorsal natatory setae. Fifth segment slightly longer than wide, with 1 medium ventral seta and 3 long dorsal natatory setae. Sixth segment slightly longer than wide, with 4 long natatory setae. Terminal (seventh) segment about 1.5 times as long as wide, with 1 shorter seta, 1 aesthetasc ya about 1/5 longer than the shorter seta and 2 long natatory setae.

A2 ( Figure 3 B) with exopodite reduced to a small plate, bearing 2 short and one long setae. Endopodite 3-segmented. First endopodal segment long and stout, aesthetasc Y short (about 1/5 of length of segment). Five natatory setae with long setules reaching the tips of the end claws, accompanying (6th) seta reaching almost half of the length of second segment. Second endopodal segment with 2 dorso-lateral and 4 ventro-lateral setae; distal chaetotaxy with three z-setae, z1 different to the others, with strong claw-like appearance, and 3 relatively long G-claws, claws G1 and G2 thick, G1 smooth and G2 with teeth, claw G3 slender. Terminal (third) endopodal segment with long claw GM, shorter claw Gm with teeth, short aesthetasc y3 fused with a seta, the latter longer than the aesthetasc and a short seta g.

Md (Figures 5B, 4C) with coxa elongated, distally set with rows of teeth and small setae, and a seta on outer edge, near the articulation with the palp. Palp with alpha-seta rather long, slender and smooth, beta-seta short, stout and hirsute, gamma-seta long, slender and smooth. First segment with two long barbed setae s1 and s2, one long smooth seta and the alpha seta. Second segment dorsally with 3 smooth setae, 2 of which longer than the other one, ventrally with 3 long and 1 shorter smooth setae as well as the beta seta. Third segment dorsally with 4 subapical setae, 2 of which longer than the other 2 setae by 1/3 of their length, ventrally with 1 long subapical seta and a short seta, medially with 4 setae (3 plus gamma-seta). Terminal segment with 3 long slender claws and 4 shorter setae.

Rake like organ ( Figure 3 A) with 8 teeth.

Mx1 ( Figure 4 A) with second palp-segment longer than broad, teeth bristles of third endite serrated. Respiratory plate (not drawn) large and elongate, distally with a row of ca. 18 or 19 ‘normal’ rays and 5 ‘reversed’ rays.

T1 (Figures 5A, 3G) with 2 a-seta, 1 d-seta and b-seta absent. Distal chaetotaxy of coxal plate (endite) (Figure 5A) consisting of 14 setae of varying shapes and lengths. Respiratory plate with 5+1 hirsute rays. Endopod ( Figure 3 G) apically with 2 long setae and 1 short seta.

T2 ( Figure 4 B): seta d1 absent, the knee segment with seta d2 of medium length. Second segment of endopodite with 1 long ventro-apical seta, reaching beyond segment 3a. Third segment divided into two sub-segments: 3a with a ventro-apical seta, reaching beyond tip of segment 3b, this segment with 1 subapical seta. Fourth, terminal, segment with 1 short subapical seta and 1 apical seta and 1 long and thick apical claw.

T3 ( Figure 3 C, F) a cleaning limb. First segment with 3 setae. Second segment with 1 apical seta. Third segment with 1 short lateral seta. Distal part of 3rd segment and 4th segment fused to a pincer shaped organ, bearing 1 long seta, 1 seta of medium length, two rows of setulae and 1 comb-like seta.

Caudal ramus (Figure 5C) with elongated, triangular base, a short subapical and a long flagellar apical seta.

Males. unknown.

Material used for the present redescription and illustrations. All material of this species used in the present paper originated from the Manezinho Backwater (coordinates: 22° 46’ 55”S, 53° 20’ 59”W), a lentic water body, created by the recently abandoned channels formed by lateral bars, located at Mutum Island, and connected to the Paraná River by a narrow and short channel ( Figure 1 , Table 1).

Seven dissected females ( MZUSP 24654; OC.3273; MZUSP 24655; MZUSP 24656, OC.3274; MZUSP 24657 and MZUSP 24658), with soft parts dissected in glycerine in a sealed slide, and five dissected females (OC.3275; OC.3276; OC.3277; OC.3274 and one specimen lost) with valves stored dry in a micropalaeontological slide.

All OC numbers are stored in the Ostracod Collection of the Royal Belgian Institute of Natural Sciences, Brussels. The MZUSP numbers are stored in the Museu de Zoologia da Universidade de São Paulo, Brazil.

See Table 1 and Figure 1 for an overview of other localities where this species was found in the upper Paraná floodplain: Lakes: Ventura, Patos, Jacaré, Pombas, Pintado, Peroba, Boca do Ipoitã, Gavião, Maria Luiza, Porcos, Guaraná, Carioca, Garças, Rivers: Ivinheima, Paraná, Baía, Backwater: Leopoldo and Channel: Cortado.

Measurements of some specimens of Cabelodopsis hispida n. gen. used for illustration (all in µm). (KM.3418 - specimen lost): LVi: L= 928, H=534; RVi: L= 922, H=524. OC.3275: CpD: L=912, W=521. OC.3276: CpLl: L=891, H=518. OC.3277: CpV: L= 927, W=539.

Scale bars: A–G, 50 Μm.

Scale bars: A–C, 50 Μm.

5. Limbs of Cabelodopsis hispida n. gen., all female. A. T, chaetotaxy of palp see Fig. 3 G (OC.3274). B. Md (OC.3273). C. Caudal Ramus.

Scale bars: A–C, 50 Μm.

Ecology and distribution. The species has been found in 19 localities out of 48 sampled in the alluvial valley of the upper Paraná River, including lakes, backwaters, rivers and channels; it is thus quite common there. It occurred mostly in the pleuston, especially in the root systems of Eichhornia crassipes . pH ranged between 4.7 and 8.2, electrical conductivity between 28.1 and 96.6 µS cm -1 and dissolved oxygen between 2.3 and 7.2 mg L -1. The species was found all year around.

Figures

FIGURE 1. Map of the area, indicating localities from where Cabelodopsis hispida n. gen. was collected.

FIGURE 2. Va l ves of Cabelodopsis hispida n. gen., all female (specimen of illustrations A – F (KM. 3418 = lost). A. LV, internal view. B. LV, internal view, detail of anterior part. C. LV, internal view, detail of posterior part. D. RV, internal view. E. RV, internal view, detail of anterior part. F. RV, internal view, detail of posterior part. G. Cp, left lateral view (OC. 3276). H. RV, detail of postero-ventral part, tilted (OC. 3274). I. Cp, dorsal view (OC. 3275). J. Cp, ventral view (OC. 3277).

FIGURE 3. Limbs of Cabelodopsis hispida n. gen., all female. A. Rake like organ (MZUSP 24657). B. A 2, for chaetotaxy of terminal segment see Fig. 3 D (OC. 3274). C. T 3, detail of pincer (MZUSP 24655). D. A 2, detail of the last segment (OC. 3274). E. A 1 (MZUSP 24658). F. T 3 (MZUSP 24655). G. T 1, palp (OC. 3274).

FIGURE 4. Limbs of Cabelodopsis hispida n. gen., all female. A. Mx 1 (MZUSP 24654). B. T 2 (OC. 3273). C. Md palp (MZUSP 24656).