Sarscypridopsis harundineti, Szwarc & Martens & Namiotko, 2021

Szwarc, Agata, Martens, Koen & Namiotko, Tadeusz, 2021, Two new Cypridopsinae Kaufmann, 1900 (Crustacea, Ostracoda) from southern Africa, ZooKeys 1076, pp. 83-107 : 83

Sarscypridopsis harundineti sp. nov.

Figures 5 , 6 , 7

Material examined.

Type locality: Botswana, North-West District, floodplains south of Okavango Delta (SA-103); grassy shore of seasonal pond near the city of Maun (Fig. 1 , Suppl. material 1: Fig. 1B ), 19°52'12"S, 23°20'23"E, elevation ca. 940 m a.s.l.; 15 Sept. 2012; T. Namiotko leg.

Holotype: • 1 ♀ (adult); dissected female stored on a permanent microscopic slide and valves stored dry on a micropalaeontological slide (RBINS INV.159064). Paratypes: BOTSWANA • 27 ♀♀ (adults); same data as for holotype ; 2 ♀♀ stored as the holotype (OC-UG 120915-3A2L, 120915-3A3L); 22 ♀♀ preserved in 96% ethanol (120915-30); 3 ♀♀ stored on micropalaeontological slides (RBINS INV.159065-INV.159067); repositories: RBINS and OC-UG. Accompanying ostracod fauna: Heterocypris oblonga (Sars, 1924); Limnocythere cf. stationis ; Plesiocypridopsis newtoni ( Brady and Robertson 1870).

Additional material.

Botswana - North-West District: • SA-96 (Fig. 1 , Suppl. material 1: Fig. 1C ): 1 juv.; endorheic Lake Ngami; 20°28'57"S, 22°42'08"E; elevation ca. 930 m a.s.l.; 12 Sept. 2012; accompanying ostracod fauna: Hemicypris inversa ; Heterocypris giesbrechti (G.W. Müller, 1898) • SA-97 (Fig. 1 , Suppl. material 1: Fig. 1D ): 11 ♀♀ and 1 juv.; Thamalakane river near the city of Maun; 19°55'52"S, 23°30'38"E; elevation ca. 940 m a.s.l.; 13 Sept. 2012; accompanying ostracod fauna: Candonopsis navicula Daday, 1910; Chrissia perarmata (Brady, 1904); Heterocypris oblonga ; Isocypris cf. priomena G.W. Müller, 1908; Limnocythere cf. stationis ; Physocypria cf. capensis (Sars, 1895); Potamocypris mastigophora (Methuen, 1910); Sarscypridopsis cf. elizabethae (Sars, 1924); Sclerocypris sp., Stenocypris malayica Victor & Fernando, 1981; Strandesia cf. prava Klie, 1935 • SA-98 (Fig. 1 , Suppl. material 1: Fig. 1E ): 6 ♀♀; floodplains south of Okavango Delta , temporary channel near the city of Maun; 19°52'15"S, 23°21'06"E; elevation ca. 940 m a.s.l.; 14 Sept. 2012; accompanying ostracod fauna: Heterocypris giesbrechti • SA-99 (Fig. 1 , Suppl. material 1: Fig. 1F ): 16 ♀♀ and 1 juv.; floodplains south of Okavango Delta , temporary channel near the city of Maun; 19°52'15"S, 23°20'45"E; elevation ca. 940 m a.s.l.; 14 Sept. 2012; accompanying ostracod fauna: Heterocypris oblonga ; Potamocypris deflexa (Sars, 1924); Potamocypris mastigophora ; Zonocypris costata ( Vávra, 1897) • SA-100 (Fig. 1 , Suppl. material 1: Fig. 1G ): 11 ♀♀; floodplains south of Okavango Delta , flooded swamp and grassland near the city of Maun; 19°52'04"S, 23°20'38"E; elevation ca. 940 m a.s.l.; 14 Sept. 2012; accompanying ostracod fauna: Heterocypris oblonga ; Stenocypris malayica ; Zonocypris tuberosa G.W. Müller, 1908 • SA-101 (Fig. 1 , Suppl. material 1: Fig. 1H ): 6 ♀♀; floodplains south of Okavango Delta , isolated pool in flooded grassland near the city of Maun; 19°51'39"S, 23°19'41"E; elevation ca. 940 m a.s.l.; 15 Sept. 2012; accompanying ostracod fauna: Heterocypris oblonga • SA-102 (Fig. 1 , Suppl. material 1: Fig. 1I ): 1 ♀; floodplains south of Okavango Delta , floodplain channel near the city of Maun; 19°52'06"S, 23°20'41"E; elevation ca. 940 m a.s.l.; 15 Sept. 2012; accompanying ostracod fauna: Heterocypris oblonga .

All individuals collected by T. Namiotko; 51 ♀♀ and 3 juv. are stored in 96% ethanol and 3 ♀♀ are stored as holotype. Repositories: RBINS and OC-UG.

Etymology.

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".

Diagnosis.

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.

Description.

Female. Cp in left lateral view (Fig. 5A ) 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 and posteriorly. LV slightly overlapping RV dorsally, RV overlapping LV ventrally (Fig. 5E-H ). External surface smooth with fine reticulation in the central area; with rare, thickly rimmed pores with extending sensilla situated mostly in the anterior and postero-dorsal parts (Fig. 5B ). Cp in dorsal (Fig. 5D ) and ventral views (Fig. 5C ) sub-elliptical, lateral margins unevenly rounded, widening posteriorly; posterior edge broadly rounded, anterior one more pointed. Greatest width situated behind mid-length. LV in internal view (Fig. 5I ) ovoid, with greatest height situated at mid-length. Anterior and posterior margins almost equally rounded, ventral margin slightly sinuous at mid-length. Anterior and posterior calcified inner lamella narrow with marginal selvage. RV in internal view (Fig. 5J ) with posterior margin broadly rounded, anterior margin more pointed and with ventral margin almost straight. Anterior and posterior calcified inner lamella wider than on LV; no selvage or inner list.

A1 (Fig. 6B ) 7-segmented. First segment with one short subapical dorsal seta (reaching beyond tip of segment) and two long ventro-apical setae. Second segment with one short dorso-apical seta (reaching 1/3 of length of next segment) and a large ventral Rome organ. Third segment ~ 0.5 × as long as wide, with two apical setae, one short dorsal seta (reaching beyond tip of next segment) and one short ventral seta (not reaching tip of next segment). Fourth segment with two long dorso-apical setae and one short ventro-apical seta (reaching 1/3 of penultimate segment). Fifth segment bearing two long ventro-apical setae and two dorso-apical setae, one long and one short (the latter nearly reaching tip of terminal segment). Penultimate segment with four long apical setae. Terminal segment with three (two long and one medium) setae and one aesthetasc ya, the latter slightly longer than the seta of medium length.

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. 6A ) with protopodite, exopodite and 3-segmented endopodite. Basal segment of protopodite with two short ventro-apical setae. Second segment of protopodite with one long ventro-apical seta. Exopodite reduced to a small plate with three setae, two short and one long. Endopodite 3-segmented. First endopodal segment with long ventro-apical seta, extending beyond tip of terminal segment; a large aesthetasc Y with a distinct distal bulbous sensory part; dorso-apically with five long natatory setae (reaching far beyond tips of terminal claws) and one shorter (6th) seta reaching 1/3 of length of next segment. Second endopodal segment undivided, medio-dorsally with two subequally long setae and medio-ventrally with four unequal setae (t1-t4), one long and three short; distally with three long z-setae (z1, z2, z3) and three long serrated G-claws: G2 thick and apically strongly serrated, G1 and G3 more slender. Terminal (third) endopodal segment subquadrate with a long serrated claw GM, a shorter (~ 1/2 length of GM) smooth claw Gm and an aesthetasc y3 fused with slightly longer accompanying seta. Aesthetascs y1, y2 and seta g not seen, the latter almost certainly absent as typical of the subfamily.

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. 6E ) and 4-segmented palp (Fig. 6C ). Md-coxa elongated, distally with rows of teeth and small setae, and with one short, smooth seta situated near the palp. First palp-segment ventro-apically with two long plumed setae (S1 and S2), one long, slender seta and a short smooth α-seta, situated in between the two S-setae. Second segment dorso-apically with three unequally long slender setae; ventrally with three long, smooth setae, one medium hirsute seta and hirsute, cone-shaped β-seta. Third segment ventro-apically with one long and one short seta; medio-apically with three setae, all reaching tip of terminal segment and a hirsute and long γ-seta; dorso-apically with four setae, all extending far beyond tips of terminal segment. Terminal segment bearing four claws, three ~ 4 × as long as terminal segment and one shorter.

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. 7A ) T-shaped, each with nine apical teeth.

Mx1with three endites and 2-segmented palp (Fig. 6D ) and a large respiratory plate (Fig. 6F ). First endite with two short setae near its base. Third endite with two smooth teeth bristles. First palp-segment with four unequal dorso-apical setae, one long, one medium and two short; medio-apically with one seta (reaching 1/2 length of terminal segment). Second segment elongated (~ 2 × as long as wide), apically with four unequal but long claws (~ 2 × as long as terminal segment). Respiratory plate large and elongate, distally with a row of more than eleven smooth rays and three long plumose rays.

Chaetotaxic formula: Palp: I: Ex-2s-1m-1l, In-1s / II: D-4m

T1 (Fig. 7B ). Protopodite with two short unequal a-setae; b-, c- and d-setae absent, endite distally with a dozen apical setae (exact number not determined). Endopod elongated, apically with one long seta (h2) and two shorter setae (h1 and h3). Respiratory plate with four long rays with swollen bases.

Chaetotaxic formula: Pr: A-2s(a and a’) / Mastic: D-? / Exo: 4l / E: D-3l

T2 (Fig. 7C, D ) a walking limb. Protopodite with seta d2 of medium length, seta d1 absent. First two endopodal segments with one long antero-apical seta each. Seta e reaching half of the penultimate segment and seta f reaching tip of terminal segment. Third endopodal segment with two antero-apical setae, one medium length g-seta and one very short seta. Fourth segment with one very short seta (h3), one short seta (h1) and long, strongly curved and serrated claw (h2); distal claw ~ 3 × as long as the second endopodal segment.

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. 7E ) a cleaning limb. Protopodite with two long setae (dp and d2) and one shorter seta (d1). First endopodal segment with short subapical e-seta. Second and third endopodal segments fused, with short f-seta not reaching tip of segment. Terminal part (fusion between distal part of third and fourth segment) a pincer organ, bearing a medium length seta (h3), a short serrated seta (h2), and a very short seta (h1), length of seta h3 ~ 2/3 that of fused segment, seta h2 ~ 1/2 length of seta h3.

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. 7F ). Reduced, with elongated, triangular base; distally with long flagellum-like seta and subapically with a short seta.

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.

Ecology.

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.

Figures

Figure 1. 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.

Figure 5. Carapace and valves of Sarscypridopsis harundineti sp. nov. ♀ A, B RBINS INV. 159066 C RBINS INV. 159067 D, E, F RBINS INV. 159065 G, H RBINS INV. 159067 A carapace left view B detail of external surface of A C carapace ventral view D carapace dorsal view E carapace posterior part, detail of D F carapace anterior part, detail of D G carapace anterior part, detail of C H carapace posterior part, detail of C I left valve external view J right valve external view Scale bars: 400 μm (A, C, D); 50 μm (B); 200 μm (E-H); 100 μm (I, J); arrows indicate anterior end.

Figure 6. Limbs of Sarscypridopsis harundineti sp. nov. ♀. A, B, E, F holotype (OC-UG 120915 - 3 A 1 L) C, D paratype (OC-UG 120915 - 3 A 3 L) 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.

Figure 7. Limbs of Sarscypridopsis harundineti sp. nov. ♀ A, B, C, F paratype (OC-UG 120915 - 3 A 3 L) D paratype (OC-UG 120915 - 3 A 2 L) E holotype (OC-UG 120915 - 3 A 1 L) 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.