Research Article |
Corresponding author: Agata Szwarc ( agata.szwarc@ug.edu.pl ) Academic editor: Ivana Karanovic
© 2021 Agata Szwarc, Koen Martens, Tadeusz Namiotko.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Szwarc A, Martens K, Namiotko T (2021) Two new Cypridopsinae Kaufmann, 1900 (Crustacea, Ostracoda) from southern Africa. ZooKeys 1076: 83-107. https://doi.org/10.3897/zookeys.1076.76123
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Two new Cypridopsinae ostracods, Potamocypris meissneri sp. nov. and Sarscypridopsis harundineti sp. nov. are described. Both were found only as asexual (all-female) populations in temporary waters of southern Africa. Potamocypris meissneri was collected from a small pan in the North-West Province of South Africa. It is approximately 0.5 mm long and belongs to the species group with long swimming setae on the second antennae. However, the species has a somewhat isolated position in the genus owing to the conspicuously reticulated carapace, which is furthermore densely covered by prominent conuli with normal pores carrying long sensilla, as well as to the wide anterior and posterior flanges on the left valve. To allow identification of the new species in relation to its closest congeners, a key to the species of the genus Potamocypris Brady, 1870 from southern Africa is provided. The genus Sarscypridopsis McKenzie, 1977 mostly has an Afrotropical distribution with only few species occurring in other regions. Sarscypridopsis harundineti was collected from floodplains of the outskirts of the Okavango Delta in Botswana. It is approximately 0.4 mm long and can be distinguished from congeners mainly by the smaller and more oval-shaped valves. We conclude that southern African Cypridopsinae urgently need integrated taxonomic revision, by means of both morphological characters and DNA-sequence data.
Afrotropical, Cyprididae, microcrustaceans, morphology, taxonomy, temporary waters
Ostracods, small bivalved crustaceans, have an impressive taxonomic diversity and functional specialisation of their appendages, which are used for locomotion, feeding, and reproduction (
Ostracoda are the extant arthropod group with the most abundant fossil record. Although much less diversified than marine lineages, freshwater ecosystems are home to ~ 2300 Recent (living) species and 270 genera (
Potamocypris Brady, 1870, is after Cypridopsis Brady, 1867, the second most abundant genus within the subfamily (
Sarscypridopsis McKenzie, 1977 is mostly distributed in South Africa, with 13 out of the 17 known species described from this country (
Here, we describe one species each belonging to Potamocypris and to Sarscypridopsis. The present paper also constitutes a contribution to the knowledge of the poorly known freshwater ostracod fauna of southern Africa and presents the first comprehensive description of a species of the genus Sarscypridopsis with full illustration of valves and appendages.
Samples were collected from temporary waters in South Africa and Botswana (Fig.
Localities of Potamocypris meissneri sp. nov. (purple star SA-9) in the North-West Province of South Africa and Sarscypridopsis harundineti sp. nov. (red dots SA-96 to SA-103) in the outskirts south of the Okavango Delta in Botswana. The type locality of Sarscypridopsis harundineti sp. nov. (SA-103) is marked with a dark red dot.
The type specimens are deposited in the Collection of the Royal Belgian Institute of Natural Sciences, Brussels (
Chaetotaxy of the limbs follows the model proposed by
Limbs:
A anterior
a, a’ two setae on Pr of T1
A1 first antenna (antennule)
A2 second antenna
alfa (α) special seta on the 1st podomere of Md palp
beta (β) special seta on the 2nd podomere of Md palp
CR caudal ramus
D distal
d1, d2, dp setae on Pr of T2 or T3
E endopod
e setae on EI of T2 and T3
EI-EIV 1st to 4th podomeres of E
Ex exterior
Exo exopod
f setae on EII of T2 and T3
g setae on EIII of T2 and T3
gamma (γ) special seta on 3rd podomere of Md palp
GM (Gm) major (minor) claw on EIV of A2
G1–3 anterior and internal claws (or setae) on EIII of A2
h1–3 setae (or claws) on EIV of T2 and T3
In interior
l large (relative length of setae or claws)
m medium (relative length of setae or claws)
Mastic masticatory process on Pr of T1
Md mandibula
Mx1 maxillula
P posterior
pl plumed
Pr protopod
s small (relative length of setae or claws)
S1–2 plumed setae on 1st podomere of Md palp
ser serrated
T1 first thoracopod (maxilliped)
T2 second thoracopod (walking leg)
T3 third thoracopod (cleaning leg)
t1–4 internal setae on EII of A2
Y aesthetasc on EI of A2
y1–3 aesthetascs on EII, EIII and EIV of A2 respectively
ya aesthetasc on the terminal podomere of A1
z1–3 external setae (or claws) on EIII of A2
Valves and carapace:
Cp carapace
H valve height
L valve length
LV left valve
RV right valve
Subclass Podocopa Sars, 1866
Order Podocopida Sars, 1866
Suborder Cypidocopina Baird, 1845
Superfamily Cypridoidea Baird, 1845
Family Cyprididae Baird, 1845
Subfamily Cypridopsinae Kaufmann, 1900
Type locality: South Africa, North-West Province, small temporary open pan (SA-9) near the village of Ganalaagte (Fig.
Holotype
: • 1 ♀ (adult); dissected female stored on a permanent microscopic slide and valves stored dry on a micropalaeontological slide (
This species is named after Dr Włodzimierz Meissner, Professor of ornithology at the University of Gdansk, Poland, a long-standing friend of TN who provided unrelenting support in the collection of ostracods from all over the world and who has encouraged and helped TN to join various scientific expeditions for collecting ostracods.
Carapace in lateral view somewhat ovoid, broadly rounded dorsally, with both extremities more or less equally rounded, ventral margin weakly concave, and maximum height situated at mid-length. Valves distinctly asymmetrical, with LV overlapping RV anteriorly and posteriorly, RV overlapping LV dorsally and ventrally. Anterior and posterior margins on LV with marginal flange, anterior one larger than posterior one. Carapace external surface hirsute, strongly ornamented with ridges, set with thickly rimmed pores with long sensilla. Antenna with long swimming setae. Terminal segment of maxillula palp spatulate with five claws. T1 with two hirsute branchial rays. CR of whip-like shape with elongated base, fused with distal long flagellum-like seta and set with additional short subapical seta.
Female. Cp in lateral view (Fig.
Carapace and valves of Potamocypris meissneri sp. nov. ♀ A
A1 (Fig.
Chaetotaxic formula: I: A-1s, P-2l / II: A-1s / III: A-1s, P-1s / IV: A-2l, P-1s / V: A-2l, P-1l-1m / VI: A-4l / VII: D: 2l-1m-ya.
A2 (Fig.
Chaetotaxic formula: Pr: 1l / Exo: 1l-2s / EI: A-5l-1m, P: Y-1l / EII+III: A-2m, P-1m(t1)-2l(t2,3)-1s(t4), D-2l(z1,z3)-1m(z2)-3l(G1,2,3: ser) / EIV: 1l(GM: ser)-1m(Gm)-y3–1m
Md with sclerotised coxa (Fig.
Chaetotaxic formula: Palp: I: In-1s(alfa)-1l-2l(S1,S2: pl) / II: In-1s(beta: pl)-1l(pl)-2m-1l, Ex:1l(pl)-2l / III: In-1l(pl)-1s, D-3m-1m(gamma), Ex-4m / IV: 2m-1l-1l(ser)
Mx1 (Fig.
Chaetotaxic formula: Palp: I: Ex-3s-1l, In-1m / II: D-5s
T1 (Fig.
Chaetotaxic formula: Pr: A-2s(a and a’) / Mastic: D-? / Exo: 2m(pl) / E: D-3l
T2 (Fig.
Chaetotaxic formula: Pr: A-1s(d2) / EI: A-1m / EII: A-1m / EIII: A-1m / EIV: P-1s(h3), D-1m(h1)-1l(h2 G:ser)
T3 (Fig.
Chaetotaxic formula: Pr: A-1l(d2)-1m(d1), P-1l(dp) / EI: A-1m(e) / EII + III: A-1s(f) / EIV: 1s(h2: ser)-1m(h3)
CR (Fig.
It should be noted that juveniles of this species do not have tubercles on the valves (see discussion).
Measurements (in μm). Cp (n = 4): L = 512–526, H = 305–306; LV (n = 11): L = 510–530, H = 278–298; RV (n = 11): L = 498–517, H = 301–319.
Male unknown.
Potamocypis meissneri was collected only from the type locality in the North-West Province of South Africa. This is an open temporary pan with the following physical and chemical water properties: pH = 7.0, electrical conductivity = 36 µS/cm and water temperature 25.8°C.
1 | Natatory setae of A2 short (not reaching tips of terminal claws | P. paludum Gauthier, 1939 |
– | Natatory setae of A2 long | 2 |
2 | Cp elongated (L ≥ 2× H), crescent-shaped | P. mastigophora (Methuen, 1910) |
– | Cp compressed (L < 2× H) , differently shaped, not crescent-shaped | 3 |
3 | Cp subtriangular, dorsally arched with blunt angle | P. gibbula (Sars, 1924) |
– | Cp with dorsal margin broadly rounded or straight on a long distance and sloping down to the posterior | 4 |
4 | Cp with posterior margin rounded; maximum height at mid-length | P. meissneri sp. nov. |
– | Cp with posterior margin straight; maximum height in front of mid-length | 5 |
5 | RV with wide dorsal overlap of LV | P. deflexa (Sars, 1924) |
– | Dorsal overlap of RV minute or lacking | P. humilis (Sars, 1924) |
Type locality: Botswana, North-West District, floodplains south of Okavango Delta (SA-103); grassy shore of seasonal pond near the city of Maun (Fig.
Holotype
: • 1 ♀ (adult); dissected female stored on a permanent microscopic slide and valves stored dry on a micropalaeontological slide (
Botswana – North-West District: • SA-96 (Fig.
All individuals collected by T. Namiotko; 51 ♀♀ and 3 juv. are stored in 96% ethanol and 3 ♀♀ are stored as holotype. Repositories:
This species is named after the term “reed-bed” (Latin: harundinetum), the original meaning of the name of the town Maun in Botswana close to the sites from where Sarscypridopsis harundineti was collected. The name Maun is derived from the language of Bantu-speaking people and translates as “the place of river reeds”.
Carapace in lateral view with anterior and posterior margins nearly symmetrically rounded, dorsal margin almost evenly rounded with greatest height situated just behind mid-length, ventral margin almost straight. RV overlapping LV anteriorly, posteriorly and ventrally, LV slightly overlapping RV dorsally. Carapace surface smooth (with fine reticulation in the central area), with rare thickly rimmed normal pores with short sensilla, situated mostly in the posterior and postero-dorsal parts. Antenna with long swimming setae, and supporting aesthetasc Y with distinctive distal bulbous sensory part. Terminal segment of maxillular palp elongated, ~ 2× as long as wide, bearing four long claws. T1 with four branchial rays. CR reduced, with elongated, triangular base.
Female. Cp in left lateral view (Fig.
Carapace and valves of Sarscypridopsis harundineti sp. nov. ♀ A, B
A1 (Fig.
Limbs of Sarscypridopsis harundineti sp. nov. ♀. A, B, E, F holotype (OC-UG 120915-3A1L) C, D paratype (OC-UG 120915-3A3L) A Second antenna B First antenna C Mandibular palp D Maxillula E Mandibular coxa F Maxillular respiratory plate. Scale bars: 100 μm. Abbreviation: ns = natatory setae.
Chaetotaxic formula: I: A-1s, P-2l / II: A-1s, P-r / III: A-1s, P-1s / IV: A-2l, P-1s / V: A-2l, P-1l-1s / VI: A-4l / VII: D: 2l-1m-ya.
A2 (Fig.
Chaetotaxic formula: Pr: 1l / Exo: 1l-2s / EI: A-5l-1s, P-Y-1l / EII+III: A-2l, P-1s(t1)-1l(t2)-2s(t3,4), D-3l(z1,z2,z3)-3l(G1,2,3: ser) / EIV: 1l(GM: ser)-1m(Gm)-y3–1s
Md with sclerotised coxa (Fig.
Chaetotaxic formula: Palp: I: In-1s(alfa)-1l-2l(S1,S2: pl) / II: In-1s(beta: pl)-1m(pl)-3l, Ex-3l / III: In-1l-1s, D-3l-1l(gamma: pl), Ex-4l / IV: 3l-1m
Rake-like organs (food-rakes) (Fig.
Mx1with three endites and 2-segmented palp (Fig.
Chaetotaxic formula: Palp: I: Ex-2s-1m-1l, In-1s / II: D-4m
T1 (Fig.
Limbs of Sarscypridopsis harundineti sp. nov. ♀ A, B, C, F paratype (OC-UG 120915-3A3L) D paratype (OC-UG 120915-3A2L) E holotype (OC-UG 120915-3A1L) A Food-rake B First thoracopod (maxilliped) C Second thoracopod (walking leg) D Second thoracopod distal end E Third thoracopod (cleaning leg) F Caudal ramus. Scale bars: 100 μm.
Chaetotaxic formula: Pr: A-2s(a and a’) / Mastic: D-? / Exo: 4l / E: D-3l
T2 (Fig.
Chaetotaxic formula: Pr: A-1m(d2) / EI: A-1l / EII: A-1l / EIII: A-1m-1s / EIV: P-1s(h3), D-1s(h1)-1l(h2 G:ser)
T3 (Fig.
Chaetotaxic formula: Pr: A-1l(d2)-1m(d1), P-1l(dp) / EI: A-1s(e) / EII + III: A-1s(f) / EIV: 1s(h2: ser)-1m(h3)
CR (Fig.
Measurements (in μm). Cp (n = 3): L = 433–464, H = 259–282; LV (n = 6): L = 430–461, H = 250–272; RV (n = 6): L = 444–473, H = 261–275.
Male unknown.
Sarscypridopsis harundineti was found in eight temporary waterbodies of the vast floodplains south of the Okavango Delta in northern Botswana. Habitats include both lotic (river side channel, floodplain channel) and lentic waters (flooded swamp, grassland, isolated pool) as well as the endorheic Lake Ngami. The species occurred at the pH range of 6.5–7.7, the electrical conductivity range of 102–464 µS/cm, and the water temperature range of 19.8–33.7 °C.
Potamocypris meissneri differs from other species of the genus by the presence of a conspicuously reticulate carapace, densely covered by prominent conuli carrying rimmed pores with long extending sensilla, and by wide anterior and posterior flanges on the left valve. Out of five southern African Potamocypris species only one, P. paludum Gauthier, 1939 (nom. nov. pro Cyprilla arcuata Sars, 1924 nec Sars, 1903 – fide Gauthier, 1939), has short swimming setae on the second antennae, which clearly distinguishes it from the new species described here. Two further species, P. mastigophora (of which Cyprilla producta Sars, 1924 is a synonym – fide McKenzie, 1971) and P. gibbula have different carapace shapes from P. meissneri: more elongated and crescent-shaped in P. mastigophora, and more subtriangular, and dorsally arched with a blunt angle in P. gibbula. The remaining two species (i.e., P. humilis and P. deflexa) are more similar to Potamocypris meissneri as they also have ornamented carapaces. However, unlike in Potamocypris meissneri, the posterior part of the dorsal margin in the two species is almost straight, sloping down and making a distinct angle with the characteristically truncated and almost straight posterior margin. In addition, none of the presently known species of Potamocypris has this type of pronounced external valve ornamentation. Potamocypris narayanani George & Martens, 2002 carries conspicuous stiff setae and has a pitted valve surface, but lacks the prominent ridges and has a huge dorsal hump on the left valve.
The originally assigned type species, S. gregaria (Sars, 1895), was placed into the synonymy of S. aculeata (Costa, 1847) by
According to
Sarscypridopsis is mostly an Afrotropical genus (
Most of the Sarscypridopsis species are poorly described and only for the following three species the morphology of the soft parts is (partly) known: S. aculeata, S. katesae (Hartmann, 1957) and S. lanzarotensis. In all three of these species, the respiratory plate of T1 carries five rays, while S. harundineti has only four rays, although admittedly this character is often very difficult to observe. Another difference between the new species and S. aculeata and S. lanzarotensis is the presence of two smooth teeth bristles on the third endite of Mx1 in S. harundineti. In the other two species the proximal bristle is serrated as is the neighboring one (
Despite of the lack of comparative characters, Sarscypridopsis harundineti can be easily distinguished from its South African congeners by the unique, more rounded valves shape, and the smaller carapace (L = 0.43–0.47 mm versus 0.54–0.80 mm). The greatest height is situated just behind mid-length in the new species, unlike in S. clavata (Sars, 1924), S. echinata (G.W. Müller, 1908), S. elizabethae, S. hirsuta (Sars, 1924), S. punctata (Sars, 1924), S. reniformis (Sars, 1924) and S. striolata (Sars, 1924) in which the dorsal margin of the carapace is more arched and the greatest height is situated more to the front. Sarscypridopsis ochracea (Sars, 1924), S. pyramidata (Sars, 1924), S. tonsa (Sars, 1924) and S. trigonella (Sars, 1924) have sub-triangular carapaces, while S. glabrata (Sars, 1924) has more elongated one. The carapace size and the shape in the lateral view of Sarscypridopsis harundineti is most similar to S. brevis (Sars, 1924) and S. sarsi (Klie, 1935). The former can be distinguished by a very hirsute external surface of the carapace, while the latter has a distinctly globular carapace in dorsal view (
Taking into account the mentioned gaps in information on taxonomic traits, we conclude that southern African Cypridopsinae, especially representatives of the genus Sarscypridopsis, urgently need integrated taxonomic revision, i.e., by means of both morphological characters (including redescriptions based on both the type and newly collected material) and DNA-sequence data.
This study was partly funded by the University of Gdansk under internal grants no. L-155-4-0089-1 and 531-D090-D818-21 attributed to TN. Julien Cillis (
Pictures of the sites from where new species Potamocypris meissneri sp. nov. and Sarscypridopsis harundineti sp. nov. were collected
Data type: Images
Explanation note: Pictures of the sites from where Potamocypris meissneri sp. nov. and Sarscypridopsis harundineti sp. nov. were collected in the North-West Province of South Africa (A) and in the floodplains south of the Okavango Delta near the town of Maun (except C) in the North-West District of Botswana (B-I), respectively. A SA-9: a small temporary open pan near the village of Ganalaagte B SA-103: grassy shore of a seasonal pond C SA-96: endorheic Lake Ngami D SA-97: Thamalakane river E SA-98: a temporary channel F SA-99: a temporary channel G SA-100: a flooded swamp and grassland H SA-101: an isolated pool in flooded grassland I SA-102: a floodplain channel.