BULLETIN DE L'INSTJTUT ROYAL DES SCiENCES NATURELLES DE BELGIQUE BIOLOGIE, 77: 29-43, 2008 BULLETIN VAN HET KONINKLIJK BELGISCH INSTITUUT VOOR NATUURWETENSCHAPPEN BIOLOGIE, 77: 29-43, 2008 • • Three further new species of the Cyprideis species flock (Crustacea, Ostracoda) from Lake Tanganyika (East Africa) by Karel WOUTERS & Koen MARTENS Abstract found that many amphipods in Lake Baikal comprised such ctyptic species, and they estimated that the real Three further new species, belonging to three genera, amphipod diversity in this ancient lake might be close of ostracods from Lake Tanganyika are described: to 1000 species, three times the mm1ber of species Tanganyikacythere rotunda sp. nov., Cyprideis romei sp. presently described and recognised. nov. and Romecytheridea concurrens sp. nov. The species The second type of cryptic species are those which primarily differ in shape of the valves, stmcture of the hinge appear scattered through molecular phylogenies. These and stmcture of the hemipenis. species, with high morphological similarity, are no sister The Cyprideis species flock of Tanganyika now consists species and their similar morphologies have originated of 23 formally described species (all endemic) in 6 genera through parallel evolution. Such cryptic species have (5 endemic). Again, these discoveries constitute mounting evidence that there might be higher numbers of cryptic been found in the Cytherissa species flock in Lake species in this flock than was previously assumed. The genera Baikal (SCHON & MARTENS, unpubl.). Here, we report Romecytheridea (derived) and Cyprideis (ancestral) are still on three ctyptic species, most likely belonging to type 1 the most speciose. species complexes, in 3 different genera. The Cyprideis species flock is the most intensively Key words: taxonomy, morphology, ancient lakes, speciation, studied ostracod radiation in the ancient Lake Cyprideis, species flock, Ostracoda. Tanganyika (ROME 1962, KISS 1959, WOUTERS 1979, 1988a, b, WOUTERS & MARTENS 1992, 1994, 1999, 2001, 2007, DUCASSE & CARBONEL 1993, 1994). The INTRODUCTION 3 new species described here bring the total number of formally described species to 23 (all endemic) in 6 The concepts of cryptic species and speciation are genera (5 endemic). becoming an important issue in studies on animal and Both past and recent expeditions to Lake Tanganyika plant biodiversity in general, and in aquatic sciences have yielded dozens of thus far unexplored samples, in particular (GOMEZ et a!., 2002, BALIAN et a!., from wide ranges of depth and latitude. It is therefore to 2008). Especially in ancient lakes, traditional Linnean be expected that further new taxa within the Cyprideis species turn out to be in fact species complexes. These species flock will be discovered. species complexes can be either monophyletic or paraphyletic. In the first type, all cryptic species are in fact sister species and their origin lies in mechanisms of diversification through natural or sexual selection TERMINOLOGY AND ABBREVIATIONS or through neutral processes, but all the time keeping morphological stasis. In most cases, sympatric sister The morphology of the copulatoty organ of Cyprideis species will become morphologically very different and related genera is complex and sometimes difficult through processes such as reinforcement and character to interpret with light microscopy. Therefore, some displacement, but in other cases emerging reproductive descriptive terms for parts of the hemipenis anatomy, isolation is not accompanied by obvious morphological important for taxonomic discrimination were ' diversification. VAINOLA & KAMALTYNOV (1999) introduced by WOUTERS & MARTENS (1994, 1999, 30 K. WOUTERS & K. MARTENS '' 2001, 2007). These are again used here. The distal part and dissected limbs preserved in a sealed glycerine of the hemipenis consists of two lobes, a larger one, preparation (O.C. 3031 b). the distal shield (DS) and a smaller one, the distal lobe Allotype: A female with valves stored dry (O.C. 3032a) (DL). The central part of the hemipenis is very complex, and dissected limbs preserved in a sealed glycerine and has, among other structures, a ventrally oriented preparation (O.C. 3032b). lobe, here called the central lobe (CL), which can be Paratypes: six dissected males and fom dissected hook-like, club-like or hammer-like in appearance. The females (O.C. 3033-3042) and one male and one female fourth structure is the actual copulatory process ( cp ). empty carapace (O.C. 3041 and 3044). As maxillule and mandible appear to have no specific features in the present species flock (see descriptions OTHER MATERIAL in WOUTERS & MARTENS, 1994, 1999), they are not described, nor illush·ated for the new species described A male with valves stored dry (O.C. 3045a) and herein. Line drawings of the hinge of the valves, finally, dissected limbs preserved in a sealed glycerine illustrate the negative parts (the sockets) in black, the preparation (O.C. 3045b), from Lake Tanganyika, positive parts (the teeth) in white. Tanzania, Kipili Islands, Mpimbwe Cape, 7° og' 15" The studied material is deposited in the Ostracod S, 30° 30' 34" E, depth 2-3 m, coarse gravel; leg.: K. Collection (O.C.) of the Royal Belgian Institute of MARTENS, 2g September 2007 (station Tang. 07/0g). Natural Sciences, Brussels (Belgium). A male with valves stored dry (O.C. 3046a) and dissected limbs preserved in a sealed glycerine preparation (O.C. 3046b), from Lake Tanganyika, TAXONOMIC DESCRIPTIONS Zambia, Kipembe, go 20' 24" S, 30° 30' 25" E, depth 10 m, sand with shell debris amongst rocks; leg.: K. Subclass Ostracoda LATREILLE, 1g06 MARTENS, 26 September 2006 (Station Tang. 06/19). Order Podocopida G.W. MULLER, 1894 Suborder Podocopina G. W. MOLLER, 1g94 DIAGNOSIS Infraorder Cytherocopina GRONDEL, 1967 Superfamily Cytheroidea BAIRD, 1g50 Large and smooth valves; female left valve with vety Family Cytherideidae SARS, 1925 rmmded appearance; hinge completely negative in the Subfamily Cytherideinae SARS, 1925 left valve and positive in the right one; first right leg in Tribe Cyprideidini KOLLMANN, 1960 the male only weakly developed as a clasping organ; hemipenis with a narrow, curved triangular distal Genus Tanganyikacythere DUCASSE & CARBONEL, shield; long and club-shaped central lobe. 1993 DESCRIPTION Tanganyikacythere rotunda sp. nov. (Pl. 1, Figs 1-11, Pl. 4, Figs 1-11) Large, thick and heavily calcified carapaces; general appearance rounded and slightly elongate; right valves DERIVATION OF NAME lower than left ones, espec1ally in females. Valves smooth. Latin: rotundus, -a, -um = rounded, because of the Female valves (Pl. 1, Fig. 2, Pl. 4, Figs 3-4, 6-7): rounded shape of the valves. dorsal margin weakly convex, especially in the right valve; anterior and posterior margins broadly rounded, TYPE LOCALITY with no marked h·ansition between the dorsal and ventral margins in the left valve; right valve with Lake Tanganyika, Zambia, Toby's Lodge, Isanga Bay, indistinct posterior cardinal angle; venh·al margin go 37' 30" S, 31° 12' 04" E, depth 1.5 m, sand with nearly straight to weakly convex in the right valve; stands of Elodea, leg.: K. MARTENS, 24 September ventral margin convex in the left valve, giving this 2006 (Station Tang. 06111 ). valve a very rounded appearance; dorsal and ventral margins nearly parallel in the right valve; carapace in TYPE MATERIAL dorsal view with indented anterior and broadly rounded posterior extremity; lateral margins nearly parallel in Holotype: A male with valves stored dry (O.C. 3031a) the middle; largest width situated near the middle of the ' New species of the Cyprideis species flock from Lake Tanganyika 31' carapace. lobe (CL) long and club-shaped, attached to the Male valves (Pl. 1, fig. 1, Pl. 4, Figs 1-2, 5) more hemipenis with a broad rounded proximal part. elongate, i.e. less high, than females; dorsal margin Abdominal extremity in the female (Pl. 1, Fig. 10 ) weakly convex, ventral margin straight; margins a wedge-shaped curved process, ventrally set with fine distinctly tapering towards the posterior; carapace in setules; furcae very small. dorsal view spindle-shaped, with blunt anterior and posterior extremities; lateral margins convex; largest MEASUREMENTS width situated near the middle. Inner lamella moderately wide in both sexes, wider Holotype (male) in males than in females; numerous sh·aight, sometimes Left valve: L 0.76 mm, H 0.46 mm bifurcated marginal pore canals (Pl. 1, Figs 1, 2); very Right valve: L 0.75 mm, H 0.42 mm shallow anterior and posterior. vestibula in the female; Allotype (female) no vestibula seen in the males. Left valve: L 0.77 mm, H 0.51 mm Muscle scar pattern consisting of a row of four Right valve: L 0.76 tmn, H 0.47 mm rounded adductor scars, a rounded U -shaped frontal Paratypes, males scar and a small fulcra! point. L 0.71-0.77 tmn, H 0.40-0.46 tm11 Hinge strongly developed (Pl. 1, Figs 1, 2, Pl. 4, Paratypes, females Figs 10, 11 ), tripartite and completely positive in the L 0.76-0.79 tmn, H 0.48-0.53 tmn right valve and negative in the left one; hinge of the right valve consisting of ca 11 anterior elongate and REMARKS obliquely oriented toothlets, a median element with ca 20 small toothlets and a posterior element with 6 large, The present species is a brooder. In four of the dissected obliquely oriented toothlets. The median element is not females the postero-dorsal pouch contained: 6 eggs and dividetl. 3 nauplii (O.C. 3039), 4 eggs and 3 nauplii (O.C. 3040), Antennule (Pl. 1, Fig. 3) five-segmented; first 10 eggs and 5 nauplii (O.C. 3041), 12 eggs and 2 nauplii segment stout, dorsa-distally set with a row of fine (O.C. 3042). setules; second segment elongate and hirsute, with long ventro-distal seta, reaching beyond t~e terminal OCCURRENCE segment; third and fourth segment short, with three strong claw-like setae and two long curved setae; fourth Tanganyikacythere rotunda sp. nov. is known from segment with very short medial seta; fifth segment long the type locality, namely Toby's Lodge, Isanga Bay and slender with a slender claw, and a short aesthetasc, (Zambia), go 37' 30" S, 31° 12' 04" E, depth 1.5 m, sand fused at its base with a curved seta. with stands of Elodea, but also from two other localities, Antenna (Pl. 1, Fig. 4) four-segmented with two namely the Kipili Islands, Kipembe (Zambia), go 20' segmented exopodite; tenninal segment small with two 24" S, 30° 30' 25" E, depth 10m, sand with shell debris stout claws. amongst rocks and Mpimbwe Cape (Tanzania), 7° og' First leg only slightly dimorphic in the male: left leg 15" S, 30° 30' 34" E, depth 2-3m, coarse gravel. (Pl. 1, Fig. 5) as in the female, with slender segments and stout terminal claw; right leg (Pl. 1, Fig. 6), only DISCUSSION weakly developed as a clasping organ, with wider segments and with longer terminal claw. Three other species of the genus Tanganyikacythere Second leg strongly dimorphic in the male: left leg have thus far been described from Lake Tanganyika: (Pl. 1, Fig. 7) as in the female, elongate and with slender T. burtonensis DUCASSE & CARBONEL, 1993, T. caljoni curved terminal claw; right leg (Pl. 1, Fig. 9) strongly WOUTERS & MARTENS, 1994 and T. .fit/gens WOUTERS reduced and weakly sclerotised. & MARTENS, 2007. The valves ofT. fulgens are larger Third leg (Pl. 1, Fig. g) not dimorphic, long and (L 0.75-0.g1 mm) than those ofT. rotunda sp. nov. (L hirsute; anterior margin of second segment set with 0.71-0.69 mm) and T. burtonensis (L 0.6g-o_go mm). T. numerous setules; terminal segment with slender and caljoni, is the smallest species of the four (L 0.62-0.69 long claw. mm). InT. caljoni the short median element of the hinge Hemipenis (Pl. 1, Fig. 11) with a natTow, curved is divided in an antero-median element and a postero triangular distal shield (DS); distal lobe (DL) narrow median element. The antero-median element consists of and curved; copulatory process ( cp) rounded; central a few tooth lets in the left valve and sockets in the right 32 K. WOUTERS & K. MARTENS I I one. In the three other species the median element is DIAGNOSIS undivided, and the hinge is completely positive in the right valve and negative in the left one. T. burtonensis Medium-sized valves, with six lateral nodes; lateral has much thicker valves, is more spherical in dorsal nodes hardly visible in dorsal view; valve surface with view and has more elongate hinge toothlets. a fine reticulation pattern with rotmded to polygonal The appendages ofT. burtonensis and T. fulgens and meshes; micro-ornamentation consisting of an indistinct T. rotunda sp. nov. show a number of similarities. The network of inter-tangled needle-like stmctures; right first leg is developed as a clasping organ in both hemipenis with bread, flame-shaped · · (rmmded species; the shape of their distal shields is quite similar, triangular) distal shield; central lobe large, consisting of although narrower and less curved in T. rotunda sp. a horizontal curved cmmection to the hemipenis and a nov. The central lobe, however, is markedly different: perpendicularly downward oriented blunt process. very elongate and club-shaped in T. rotunda, hook-like in T. burtonensis and suboval and slightly curved in T. DESCRIPTION fit/gens. The similarities between the three species most likely reflect their close relationship. Medium-sized elongate suboval valves; male valves only little lower than females. Valves in both sexes with six relatively small nodes: a small antero-dorsal Genus Cyprideis JONES, 1857 one and an elongate medio-dorsal one, with a shallow sulcus between the two nodes; third node small, situated Cyprideis romei sp. nov. postero-dorsally, fourth node is the subcentral h1berde, (Pl. 2, Figs 1-11, Pl. 5, Figs 1-11) fifth node elongate, situated media-ventrally and finally a postero-ventral node, being larger and more venh·ally DERIVATION OF NAME situated in females than in males. Valve surface covered with a fine reticulation pattern, consisting of polygonal Named after DOM Remade Joseph ROME (1893-1974), to rounded meshes; muri set with very fine micro who published an important monograph on Tanganyikan ornamentation, consisting of an indistinct network of ostracods (1962), and who was mentor of one of us inter-tangled needle-like stmctures. (KW) from 1966 to 1970. After so many years, KW Female valves (Pl. 2, Fig. 2, Pl. 5, Figs 3, 4): dorsal still remembers this fine and emdite gentleman with margin nearly straight, but with postero-dorsal brood gratitude and pride. pouch slightly protmding over the (straight) hinge line; anterior margin broadly rounded; posterior margin TYPE LOCALITY tmncate; ventral margin nearly straight; maximum height in the posterior tenth of the valves; carapace Lake Tanganyika, Zambia, Chimba, W. of Sumbu, (Pl. 5, Fig. 8) in dorsal view wedge-shaped, with blunt 8° 25' 29" S, 30° 27' 27" E, depth 9 m, coarse sand, anterior and narrowly rounded posterior extremity; collected by SCUBA with handnet, leg.: K. MARTENS, 25 lateral margins somewhat irregular; lateral nodes hardly September 2006 (Station Tang.06114). visible in dorsal view. Male valves (Pl. 2, Fig. 1, Pl. 5, Figs 1, 2) more TYPE MATERIAL elongate, i.e. less high than females; dorsal margin nearly straight; ventral margin weakly convex; anterior Holotype: a male with valves stored d1y (O.C. 3047a) margin broadly rounded; posterior margin evenly and dissected limbs preserved in a sealed glycerine rounded; dorsal and ventral margins tapering towards preparation (O.C. 3047b). the posterior. Carapace (Pl. 5, Fig. 9) nanow, with Allotype: a female with valves stored d1y (O.C. nearly parallel margins; lateral margins somewhat 3048a) and dissected limbs preserved in a sealed inegular mainly caused by the protmding medio-dorsal glycerine preparation (O.C. 3048b). node; anterior extremity pointed, posterior extremity Paratypes: six dissected males and five dissected triangular. females (O.C. 3049-3059) and one female and one male Anterior itmer lamella rather narrow, posterior one empty carapace (O.C. 3060 and 3061). narrow; numerous straight, rarely bifurcated marginal pore canals (Pl. 2, Figs 1-2); vety shallow anterior vestibula; no posterior vestibula; muscle scar pattern consisting of a row of four oval adductor scars, a I I New species of the Cyprideis species flock from Lake Tanganyika 33 rounded U-shaped frontal scar and a small fulcra! MEASUREMENTS point. Hinge (Pl. 2, Figs 1-2, Pl. 5, Figs 5, 6, 7, 10) Holotype (male) consisting of three elements: anterior element, median Left valve: L 0.68 mm, H 0.36 mm element (divided in antero-median and postero-median Right valve: L 0.66 mm, H 0.34 nun element) and posterior element; right valve hinge: Allotype (female) anterior element positive, consisting of 10 small Left valve: L 0.73 nu11, H 0,40 nun toothlets; antero-median element negative, a crenulated Right valve: L 0.71 nm1, II 0,38 mm groove; postero-median element, a crenulated bar, Paratypes, males with indistinct toothlets; posterior element positive, L 0.65-0.71 nm1, H 0.34-0.40 mm consisting of ca 6 toothlets. Hinge of the left valve Paratypes, females complementary with a comparable number of teeth, L 0.70-0.74 mm, H 0.38-0.41 mm toothlets and sockets. Antennule (Pl. 2, Fig. 3) five-segmented; first REMARKS segment stout; second segment elongate, with long ventro-distal seta, reaching to the tip of the terminal The present species is a brooder. In three of the aethetasc; third and fourth segments short, with three dissected females the postero-dorsal pouch contained: relatively short and stout claws and two curved setae; 11 eggs and 5 nauplii (O.C. 3055), 8 eggs and 7 nauplii fourth segment with short medial seta; fifth segment (O.C. 3056), 2 eggs (O.C. 3057). long and narrow, with long and slender curved seta, and a long aesthetasc, fused at its base with a long and OCCURRENCE slender, nearly straight seta of the same length. Antenna (Pl. 2, Fig. 4) four-segmented with two Cyprideis romei sp. nov. is only known from the type segmented exopodite; third segment with one long and locality, namely Chimba, W. ofSumbu (Zambia), 8° 25' one short antero-median seta, and two short claw-like 29" S, 30° 27' 27" E, depth 9 m, coarse sand. setae and a long and slender curved seta; distal claw stout; terminal segment very small with two large DISCUSSION claws. First leg dimorphic in the male: left leg (Pl. 2, Fig. Six other species of the genus Cyprideis have thus 6) as in the female, with slender segments; right leg (Pl. far been described from Lake Tanganyika, namely 2, Fig. 5) developed as a clasping organ, with a wide C. loricata WOUTERS & MARTENS, 2001, C. mastai terminal segment and a strong claw. WOUTERS & MARTENS, 1994, C. profimda WOUTERS Second leg strongly dimorphic in the male: left leg & MARTENS, 1999, C. rumongensis WOUTERS & (Pl. 2, Fig. 8) as in the female, with slender and curved MARTENS, 1994, C. spatula WOUTERS & MARTENS, terminal claw; right leg (Pl. 2, Fig. 9) strongly reduced, 1999 and C. aciculata WOUTERS & MARTENS, 2007. indistinctly segmented and weakly sclerotised. Only two of these six species, C. loricata and C. Third leg (Pl. 2, Fig. 7) not dimorphic, long and aciculata have strongly ornamented valves, the others very hirsute; anterior margin of second segment set have smooth or more or less pitted valves. C. loricata with bundles of setules; terminal segment with long and is a larger species (L 0.93-1.01 mm), with heavily narrow claw. calcified valves. C. aciculata (L. 0.70-0.80 mm) and C. Hemipenis (Pl. 2, Fig. 11) with broad, flame-shaped romei sp. nov. (L 0.65-0.74 nun) are much smaller and (rounded triangular) distal shield (DS); distal lobe less calcified. C. aciculata and C. romei resemble each (DL) narrow and weakly curved; copulatory process other closely. C. aciculata, however, has less elongated ( cp) rounded; central lobe (CL) large, consisting valves (C. aciculata: height/length LV male holotype: of horizontal curved connection to hemipenis and 0.58; LV female allotype: 0.59 versus C. romei: perpendicularly downward oriented blunt process. height/length LV male holotype: 0.53; LV female Abdominal extremity in the female (Pl. 2, Fig. 10 ) a allotype: 0.55). The hinge of C. aciculata is much slightly curved narrow wedge-shaped pointed process; sh·onger developed, with larger teeth and toothlets. In furcae small. C. romei the lateral nodes are hardly visible in dorsal view, whereas in C. aciculata they are very prominent. Furthermore, the micro-ornamentation in C. aciculata consists of very fine needle-like spines, whereas in C. I I 34 K. WOUTERS & K. MARTENS romei the micro-ornamentation is an indistinct network of hemipenis (DS) wide, with convex posterior margin of inter-tangled needle-like structures. The most and anterior margin with convexity in the middle and striking difference between C. aciculata and C. romei sharp indentation distally; central lobe consisting of a sp. nov. is in the morphology of the hemipenis. In C. horizontal straight connection to the hemipenis, and a romei the dorsal shield is broad, flame-shaped (rounded downward oriented long and pointed hook-like process triangular), versus narrow and apically truncate in C. and an upward oriented semicircular widening. aciculata. The central lobe in C. romei consists of a horizontal curved connection to the hemipenis and DESCRIPTION a perpendicularly downward oriented blunt process, whereas in C. aciculata the central lobe consists of Small, elongate valves with tapering dorsal and ventral a horizontal straight connection to the hemipenis, a margins; strong anterior marginal rim; valve surface perpendicularly downwaI rd oriented hook-like process reticulated; zone behind anterior tim smooth; valves and a short and blunt upward oriented process. without nodes or ridges; surface reticulated; reticulation absent in a wide zone behind the anterior marginal rim; muri set with delicate micro-omamentation (Pl. Genus Romecytheridea WOUTERS, 1988 6, Fig. 1) consisting of minute pustules. Inner lamella in both sexes wide, with numerous mostly branched Romecytheridea concurrens sp. nov. marginal pore canals (Pl. 3, Figs 1-2); anterior (Plate 3, Figs 1-11, Plate 6, Figs 1-11) vestibulum shallow, posterior vestibulum sr;t.all and very shallow; sh·ongly developed selvage in both sexes. DERIVATION OF NAME Hinge tripartite and consisting of anterior, median and posterior elements; median element bipartite. Hinge of _.Latin: present participle of concurrere = to taper; right valve (Pl. 3, Fig. 1): anterior element with 10-11 because of the tapering dorsal and ventral margins, small toothlets; antero-median element with numerous especially in the male valves. (ca 10) vety small sockets; postero-median element a bar-like crenulated structure with a large number of TYPE LOCALITY small toothlets; posterior element consisting of about six small toothlets. Left valve hinge complementaty Lake Tanganyika, Zambia, Kipembe, 8° 20' 24" S, 30° (Pl. 3, Fig. 2) 30' 25" E, depth 10m, sand with shell debris amongst Male valves (Pl. 3, Fig. 1, Pl. 6, Fig. 1-2) with rocks, collected by SCUBA with hand net, leg.: K. nearly straight dorsal margin; anterior broadly rounded; MARTENS, 26 September 2006 (Station Tang. 06119·). posterior margin narrowly rounded, with a blunt triangular appearance; ventral margin straight, with TYPE MATERIAL antero-ventral concavity; dorsal and ventral margins distinctly tapering; male carapace (Pl. 6, fig. 9) in dorsal Holotype: a male with valves stored dry (O.C. 3062a) view very narrow, with nearly parallel lateral margins, and dissected limbs preserved in a sealed glycerine with truncate anterior extremity, marked by the presence preparation (O.C. 3062b). of a marginal rim; pvsierior extremity tnmcate; lateral Allotype: a female with valves stored dry (O.C. margins convex in the middle. 3063a) and dissected limbs preserved in a sealed Female valves (Pl. 3, Fig. 2, Pl. 6, Figs 3-4) large and glycerine preparation (O.C. 3063b). higher than males; dorsal and ventral margins tapering, Paratypes: one dissected male and two dissected but less so than in males; anterior margin long and broadly females (O.C. 3064-3066). rounded, posterior margin truncate; micro-omamentation as in males; female carapace (Pl. 6, Fig. 8) with anterior DIAGNOSIS exh·emity truncate by the presence of a marginal rim; posterior extremity truncate; lateral margins nearly Valves medium-sized, regularly reticulated; dorsal straight with a convexity in the middle; maximum height and ventral margins tapering, especially in the males; posteriorly situated at 4/5 of the length. anterior margin vety broadly rounded; nodes absent; Antennule (Pl. 3, Fig. 3) five-segmented; first eye tubercle weakly developed; strongly developed segment short and broad; second segment about twice as selvage; third and fourth segments of male right first long as wide; third segment vety short, fourth segment leg fused, with vague remnants of a suture; distal shield slightly more elongated; fifth segment twice as long as I I New species of the Cyprideis species flock from Lake Tanganyika 35 wide; antero-distal seta of second segment reaching REMARKS beyond the tip of the fifth segment; third segment with a distal claw, and fourth segment with one stout and The present species is a brooder. In the three dissected one long and slender curved seta; medial seta of fourth females the postero-dorsal pouch contained: 14 nauplii segment moderately long; fifth segment slender with a (O.C. 3063), 9 eggs and 3 nauplii (O.C. 3065), 6 eggs rather thin claw-like seta, and a long aesthetasc, fused at and 6 nauplii (O.C. 3066). the base with a curved long seta. Antenna (Pl. 3, Fig. 4) four-segmented, with OCCURRENCE three-segmented exopodite; third segment with three medially inse1ted relatively short posterior setae; Romecytheridea concurrens sp. nov. is only known nanow distal posterior claw-like seta and one long from the type locality namely Kipembe (Zambia), 8° and one short curved anterior seta; claws of terminal 20' 24" S, 30° 30' 25" E, depth 10m, sand with shell segment moderately long. debris amongst rocks. First leg only slightly dimorphic in the male: left leg (Pl. 3, Fig. 6) slender, as in the female; right leg (Pl. 3, DISCUSSION Fig. 5), developed as a clasping apparatus, with broad third and fourth segments; third and fourth segments Six other species of the genus Romecytheridea have fused, with an incomplete and indistinct suture in the thus far been described from Lake Tanganyika, namely middle; distal claw not centrally, but ventrally inserted. R. amp/a WOUTERS, 1988, R. bacata WOUTE~~ & Second leg dimorphic in the male; right leg (Pl. 3, MARTENS, 2007, R. be/one, WOUTERS & MARTENS, Fig. 9) strongly reduced and weakly sclerotised; left 2001, R. !ongior WOUTERS & MARTENS, 1999, leg (Pl. 3, Fig. 8) as in the female, slender, with short R. p!egma WOUTERS & MARTENS, 2001 and R. terminal claw. tenuisculpta (ROME, 1962). R. longior lacks the anterior Third leg (Pl. 3, Fig. 7) not dimorphic, but long and marginal rim, present in R. concurrens, and in the other slender, hairy, with bundles of setulae, and with long known Romecytheridea-species. R. be lone differs by its and slender weakly curved terminal claw. strongly branched anterior marginal pore canals, and Hemipenis (Pl. 3, Fig. 11): distal shield (DS) broad, by the very different morphology of the hemipenis, slightly curved and overall triangular in shape, with with a distally pointed triangular distal shield and a convex posterior margin and anterior margin with large club-shaped central lobe. R. concurrens sp. nov. convexity in the middle and sharp indentation distally; is characterised by the fusion of the third and fomth distal lobe (DL) shorter than distal shield, slightly segments of the male right first leg. This feature is curved, with parallel margins; copulatory process ( cp) only seen in two other Romecytheridea species, namely large and rounded lobe; central lobe (CL) somewhat S R. plegma and R. tenuisculpta. The valves of both shaped, consisting of a horizontal straight connection species show an overall similarity with R. concurrens. to the hemipenis, and a downward oriented long and The latter differs, however, by the strongly tapering pointed hook-like process and an upward oriented dorsal and ventral margins, especially in the males. semicircular widening. Furthennore, the central lobe of the hemipenis of R. Female abdominal extremity (Pl. 3, Fig. 10) a plegma is spoon-shaped: From all Romecytheridea long and nanow, curved process with inegular lateral species, R. concurrens sp. nov. is most closely related margins; genital lobe with rounded anterior and to R. tenuisculpta. Both species have large valves, triangular posterior margin (as in other Romecytheridea with a strongly developed selvage. The valves of R. species); furcae small. tenuisculpta have nearly parallel dorsal and ventral margins, a stronger developed eye tubercle, and a MEASUREMENTS medium-sized postero-ventral node. The central lobe of R. tenuisculpta is very long, narrow, and distally Holotype (male): sh·ongly curved and needle-like (based on ROME, 1962, Left valve: L 0.60 mm, H 0.31 mm and on specimens in the collections of the RBINS, O.C. Right valve: L 0.59 mm H 0.29 mm 3067-3070). In R. concurrens this lobe consists of a Allotype (female): horizontal straight connection to the hemipenis, and a Left valve: L 0.70 m111, H 0,22 mm downward oriented long and pointed hook-like process Right valve: L 0.68 m111 H 0.34 mm and an upward oriented semicircular widening. Paratypes: L 0.59-0.68 mm , H 0.28-0.36 mm 36 K. WOUTERS & K. MARTENS II Table 1. List of the ach1ally known species of the The c1yptic species from the same genus seem to differ Cyprideis species flock of Lake Tanganyika (in mainly in the shape and stmchrre of the male copulatory alphabetical order). appendages. Other, but less pronounced, differences are in the shape and number of segments of sex-specific limbs (first right limbs in males, developed into clasping Genus Archeocyprideis DUCASSE & CARBONEL, 1994 organs), the shape of the valves and the development of 1. A. tubercu!ata DUCASSE & CARBONEL, 1994 the hinge. The first two sets of characters, h~mipenes and first Genus Cyprideis JONES, 1857 limbs, are all used by males to stimulate··females into 2. C. aciculata WOUTERS & MARTENS, 2007 accepting them as mates for reproduction (DANIELOPOL 3. C. loricata WOUTERS & MARTENS, 2001 et a!, 1990). The relative morphological stasis in other 4. C. mastai WOUTERS & MARTENS, 1994 morphological modules of these species complexes 5. C. profunda WOUTERS & MARTENS, 1999 seems to indicate that especially sexual, and not nahlral, 6. C. romei sp. nov. (this paper) selection has been the driving force in this c1yptic 7. C. rumongensis WOUTERS & MARTENS, 1994 speciation. 8. C. spatula WOUTERS & MARTENS, 1999 At present, the Tanganyikan Cyprideis species flock comprises 23 species in 6 genera (see Tablel) Genus Kavalacythereis WOUTERS, 1979 9. K. braconensis WOUTERS, 1979 ACKNOWLEDGEMENTS Genus Mesocyprideis WOUTERS & MARTENS, 1992 10. M irsacae (Kiss, 1959) The present new species were described on mate1ial 11. M nitida WOUTERS & MARTENS, 2001 collected during the first and second Tanganyika 12. M pita WOUTERS & MARTENS, 1999 expedition of the ESF Eurocore project MOLARCH (Molecular archives of climatic history: exploring Genus Romecytheridea WOUTERS, 1988 patterns of genomic differentiation in endemic species 13. R. amp/a WOUTERS, 1988 radiations of ancient lakes- coordinator E. VERHEYE N). 14. R. bacata WOUTERS & MARTENS, 2007 KM acknowledges the help of the entire expedition 15. R. belone WOUTERS & MARn;NS, 2001 team, 16. R. concurrens sp. nov. (this paper) 17. R. !ongior WOUTERS & MARTENS, 1999 18. R. p/egma WOUTERS & MARTENS, 2001 REFERENCES 19. R. tenuisculpta (ROME, 1962) BALIAN, E., SEGERS, H., LEVEQUE, C. & MARTENS, K., 2008. Genus Tanganyikacythere DUCASSE & CARBONEL, 1993 The freshwater animal diversity assessment: an overview of 20. T burtonensis DUCASSE & CARBONEL, 1993 the results. In: BALIAN, E. et al. (eds.): Freshwater animal 21. T caljoni WOUTERS & MARTENS, 1994 diversity assessment. Hydrobiologia, 595: 627-637. 22. T fit!g ens WOUTERS & MARTENS, 2007 DANIELOPOL, D.L., MARTENS, K. & CASALE, L.M., 1990. 23. T rotunda sp. nov. (this paper) Revision of the genus ·Leucocythere KAUFMANN, 1892 (Cmstacea, Ostracoda, Limnocytheridae), with the description of a new species and two new tJibes. Bulletin de l'lnstitut royal des Sciences naturelles de Belgique, Biologie, 59 (1989): 63- GENERAL DISCUSSION 94. The present material was collected in the framework of DUCASSE, 0. & CARBONEL, P., 1993. Tanganyikacythere the ESF Eurocore-project MOLARCH, which searches nov. gen. (Cytherideinae, Osn·acoda) du Lac Tanganyika: for fingerprints of past climatic events (i.e. lake level systematique des valves, d01mees ecologiques. Geobios, 26(4): fluctuations) in extant populations of several model 427-447. groups of ancient lake organisms, including the Cyprideis DUCASSE, 0. & CARBONEL, P., 1994. Cytherideinae (Crustacea, species flock. Both intra- and interspecific molecular Osn·acoda) Recents du Lac Tanganyika. Archeocyprideis phylogenies of the Cyprideis species flock will be built , tuberculata n. gen. n. sp.: Systematique, disn·ibution, ecologie. and these trees will falsify the hypothesis that the present Revue de Micropaleontologie, 37(2): 97-112. cryptic species belong to monophyletic clusters (Type 1). New species of the Cyprideis species flock from Lake Tanganyika 37, GOMEZ, A., SERRA, M., CARVALHO, G.R. & LUNT, D.H., 2002. WOUTERS, K. & MARTENS, K., 1999. Four new species Speciation in ancient cryptic species complexes: evidence from of the Cyprideis species flock (Cmstacea: Ostracoda) of the molecular phylogeny of Brachionus plicatilis (Rotifera). Lake Tanganyika. Bulletin de l'Institut Royal des Sciences Evolution, 56(7): 1431-1444. Naturel!es de Belgique, Biologie, 69: 67-82. Kiss, R. 1959. Quelques ostracodes nouveaux et interessants WOUTERS, K. & MARTENS, K., 2000. On the taxonomic de Ia region de I'extremite nord du lac Tanganyika. Revue de position of the genera Archeocyprideis and Kavalacythereis Zoologie et de Botanique africaines, 59(1/2): 81-105. of the Cyprideis species flock (Cmstacea, Ostracoda) in Lake Tanganyika (East Africa), with the first descliption of the MARTENS, K., 1994. Ostracod speciation in ancient lakes: a appendages. Bulletin de l'Institut Royal des Sciences Nature/les review. In: MARTENS, K., B. GODDEERIS & G. COULTER (eds.), de Belgique, Biologie, 70: 207-216. Speciation in Ancient Lakes. Advances in Limnology, 44: 203- 222. WOUTERS, K. & MARTENS, K., 2001. On the Cyprideis species flock (Cmstacea, Ostracoda) in Lake Tanganyika, with the ROME, D.R. 1962. Ostracodes. Eiploration Hydrobiologique description of four new species. Hydrobiologia, 450: 111-127. duLac Tanganika (1946-1947), Resultats Scientifiques, 3(8): WOUTERS, K. & MARTENS, K., 2007. Three new species of 1-304. the Cyprideis species flock (Crustacea, Ostracoda) of Lake V ATN6LA, R. & KAMAL TYNOV, R. M., 1999. Species diversity Tanganyika (East Africa). Bulletin de I'Jnstitut Royal des and speciation in the endemic amphipods from Lake Baikal: Sciences Naturelles de Belgique, Biologie, 77: 147-160. molecular evidence. Crustaceana, 72: 945-956. WOUTERS, K., 1979. Kavalacythereis braconensis gen. n. Karel WOUTERS sp. n., a remarkable new cytheracean ostracod genus and species from Lake Tanganyika (Zaire). Annates dele Societe Department of Invertebrates zoologique de Belgique, 108(3-4): 179-187. Royal Belgian Institute ofNatmal Sciences Vautierstraat 29 WOUTERS, K., 1988a. On Romecytheridea tenuisculpta B-1 000 Bmssels, Belgiwn (Rome). Stereo-Atlas of Ostracod Shells, 15(2): 97-100. (Karel. [email protected]) WOUTERS, K., 1988b. On Romecytheridea amp/a Wouters sp. nov. Stereo-Atlas of Ostracod Shells, 15(2): I 01-106. Koen MARTENS · WOUTERS, K. & MARTENS, K., 1992. Contribution to the Freshwater Biology knowledge ofTanganyikan cytheraceans, with the description Royal Belgian Institute ofNatmal Sciences of Mesocyprideis nom. nov. (Cmstacea, Ostracoda). Bulletin Vautierstraat 29 de l 'lnstitut Royal des Sciences Naturelles de Belgique, B-1 000 Bmssels, Belgium Biologie, 62: 159-166. ([email protected] e) WOUTERS, K. & MARTENS, K., 1994. Contribution to the knowledge of the Cyprideis species flock (Cmstacea: Ostracoda) of Lake Tanganyika, with the description of three new species. Bulletin de l'Institut Royal des Sciences Naturelles de Belgique, Biologie, 64: 111-128. '' 38 K. WOUTERS & K. MARTENS 10- Plate I. Tanganyikacythere rotunda sp. nov., Lake Tanganyika, Zambia, Toby's Lodge, Isanga Bay. Fig. 1. Right valve, male, holotype, internal view (O.C. 3031). Fig. 2. Left valve, female, allotype, intemal view (O.C. 3032). Fig. 3. Antennule, male, holotype. Fig. 4. Antetma, male, holotype. Fig. 5. Left first leg, male, holotype. Fig. 6. Right first leg, male, holotype. Fig. 7. Left second leg, male, holotype Fig. 8. Third leg, male, holotype. Fig. 9. Second right leg, male, holotype. Fig. 10. Abdominal extremity, female, paratype (O.C. 3042). Fig. 11. Hemipenis, holotype. Scales: Figs 1-2: 200 !l111; Figs 3-11: 50 !ll11.