PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON 118(4):706±730. 2005. nilotica (P. Roux, 1833) (Crustacea: : : ) from East , with descriptions of four new species

Jasmine Richard and Paul F. Clark (JR) formerly Department of Zoology, Bharathi Women's College, Chennai 600 108, India, email: [email protected] (PFC) Department of Zoology, The Natural History Museum, Cromwell Road, London SW7 5DB, England, email: [email protected]

Abstract.ÐCaridina nilotica (P. Roux, 1833) is redescribed and its distri- bution restricted to the River catchment area, although con®rmation is required of the presence of this species from the Blue Nile. Material identi®ed as C. nilotica from outside this African area requires clari®cation and probably belongs to other species of Caridina. Two independent collections of atyids from , , which is not part of the Nile catchment, were re-examined and found to comprise four new Caridina species. These are de- scribed and illustrated, and a key is provided distinguishing the new species from C. nilotica.

Hussein and Obuid-Allah (1992a: 122) of the rostrum and the ®rst thoracic leg. As appeared to synonymize Caridina longiros- a result, he concluded that C. nilotica was tris H. Milne Edwards, 1837, C. grandiros- an extremely heterogeneous complex of tris Stimpson, 1861, C. leucosticta Stimp- forms extending from Central Africa to the son, 1861, C. wyckii (S. I. Hickson, 1888) West Paci®c and that its morphology was and C. nilotica typica De Man, 1908 with so variable that it was unde®nable. Later, C. nilotica (P. Roux, 1833). They (Hussein Johnson (1963) argued that some tentative and Obuid-Allah 1992a) referred to their attempts should be made to separate the nil- material (collected from Asyut, Egypt) as otica complex into species and suggested C. nilotica nilotica but they failed to clarify that typical was essential- the status of the synonymized taxa±were ly African. The present study is more rad- these synonymies subspeci®c (i.e., C. nilo- ical with regard to the distribution of Car- tica leucosticta), or speci®c (i.e., C. niloti- idina nilotica, restricting it to the River Nile ca)? This nomenclatorial confusion raised watershed. old problems relating to the distribution and The Nile ¯ows south to north over 35 of C. nilotica. In effect, Hussein degrees of latitude and is the longest river and Obuid-Allah (1992a) had resurrected in the world, with a length of over 6800 the ''nilotica complex'' with a suggested km. Its catchment is vast, with an estimated distribution from East Africa to the West area of 3.3 million km2, including ca. Paci®c. 81,500 km2 of lakes and ca. 70,000 km2 of Johnson (1960) stated that Caridina had swamps. There are ten riparian countries long been a dif®cult to study. He along the Nile±Burundi, Democratic Re- considered that this was due in part to the public of Congo, Egypt, Eritrea, Ethiopia, small morphological differences that sepa- Kenya, , Sudan, Tanzania and rated closely related Caridina species and Uganda. For the present study, Caridina in part to the variability that many species nilotica material was examined from Lake showed in characters such as the armature Tanganyika northward to Lakes Victoria VOLUME 118, NUMBER 4 707 and Albert, the , and Nile. Gor- Measurements.ÐAdults were measured don (1930, 1933) had previously examined from the anterior tip of the rostrum to the most of this material. Unfortunately, the posterior margin of the telson. Carapace presence of C. nilotica from the Blue Nile length was measured from the postorbital could not be con®rmed, as Caridina mate- margin to the posterior margin of the car- rial from this river was not available. apace. Of particular interest was the material Description.ÐAppendages without dis- studied by Gordon (1933) from Lake Bun- tinguishing characters are ®gured but not yonyi (Bunyoni), Kabale District, in the described; these include maxillule, maxilla, southwestern region of Uganda. Lake Bun- ®rst maxilliped, second maxilliped, third yonyi has an area of approximately 6100 maxilliped, fourth pereopod, and second hectares, is about 25 km long and 7 km male pleopod. wide, is about 1950 m above sea level, has 29 islands, and is the second deepest lake Taxonomy in Africa (900 m). Lake Bunyonyi is not part of the Nile catchment; it is isolated. Caridina nilotica (P. Roux, 1833) There were two separate collections from Figs. 1±4 the lake in the Natural History Museum, Pelias niloticus P. Roux, 1833: 73, pl. 7, London. The ®rst comprises three jars reg- ®g. 1. istered under the numbers 1934.2.8.8±37, Caridina nilotica, De Man, 1908: 255, pl. 38±87, 88±90, from the Cambridge Expe- 20, ®gs. 1 & 2; Calman, 1928: 738; Gor- dition to the East African Lakes, 1930±31, don, 1930: 33, ®g. 13b, c; 1933: 351 collected by E. B. Worthington during Au- (part); Woltereck, 1942: 279, ®gs. 12 & gust 1931, reported on by Gordon (1933) 13 (part). and identi®ed by her as Caridina nilotica. Caridina nilotica gracilipes, Calman, 1906: The second collection was unregistered un- 189±191 (part). til the present study and was labelled Car- Caridina nilotica typica, Bouvier, 1925: idina sp., Lake Bunyuni, coll. J. Ford, and 146 (part). is assumed to be collected some time after Caridina nilotica nilotica, Hussein & Ob- the Cambridge Expedition as Gordon uid-Allah, 1992a: 121, ®gs 1±7 (part); (1933) did not report on this material. The 1992b: 203, ®gs 1±4. Caridina material contained within these four jars could be divided into four groups Material examined.ÐEgypt: Port Said, that were morphologically distinct from the pres. R. Gurney, NHM 1921.4.27.38±42, 5 Nile catchment species, C. nilotica. males, 3 females, 1 juv.; NHM 2004.1557± The purpose of this study is to redescribe 59, 1 female ovig., 1 female; Nile near Cai- Caridina nilotica, describe four new Cari- ro, coll. & pres. Capt. S.S. Flower, NHM dina species from Lake Bunyonyi, Uganda, 1906.6.1.5±9, 1 male, 6 females ovig., 1 fe- and present a key separating these ®ve spe- male; NHM 2004.2560±62, 1 female ovig., cies. 1 female; near Cairo, Egypt, NHM Abbreviation used.ÐNHM ϭ Natural 2004.2541±50, 6 males, 1 female ovig.; History Museum, London; MNHN ϭ Mu- NHM 1950.1.2.145±146, 2 females ovig.; seÂum national d'Histoire naturelle, Paris; Nile near Al Qanatir Al Khayriah (Qanatir RMNH ϭ Nationaal Naturhistorisch Mu- Muhammad Ali), MNHN D39199, 4 males, seum (ex Rijksmuseum van Natuurlijke 2 females ovig., 2 females; Giza, pres. Capt. Historie, Leiden); E.A.F.R.O. ϭ East Afri- S.S. Flower, NHM 1908.4.11.1±5, 10 can Fisheries Research Organisation; stn ϭ males, 1 female ovig.; Haremilik Canal, station; ovig. ϭ ovigerous; juv. ϭ juveniles; Zoological Survey of Egypt, NHM coll. ϭ collected; pres. ϭ presented. 1922.11.22.36±55, 20 males, 60 females 708 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON

Fig. 1. Caridina nilotica. Female from NHM 1928.8.28.12. a. lateral view; b. antennular peduncle; c. an- tennal scale; d. mandibles; e. maxillule; f. maxilla; g. ®rst maxilliped; h. second maxilliped; i. third maxilliped. Scale bars: a ϭ 1 mm; b±i ϭ 0.5 mm. VOLUME 118, NUMBER 4 709 ovig., 5 females; NHM 2004.1551±56, 1 Murchinson Falls, coll. E.B. Worthington male, 2 females ovig.; Cambridge Expedi- and Michael Graham, NHM 1929.10.23.3± tion to Suez Canal 1924, Timsha Lagoon, 42, 2 females ovig., 3 females; Lake Kwan- NHM 1927.11.2.53±72, 25 males, 8 fe- ia local lacustrine modi®cations, NHM males ovig., 36 females, 58 juv.; Lake Is- 1929.10.23.3±42, 9 males, 1 female; Cam- mailia, NHM 1927.11.2.73±77, 11 males, 5 bridge expedition to East African Lakes females ovig., 24 females; Lake Nasser, 1930±1931, stn 617, , coll. P.C. Raheja, Development Centre, 1934.2.8.3±7, 3 males, 2 females ovig., 2 NHM 1969.976, 5 males, 5 females ovig., females; Entebbe, (Victoria 5 females; NHM 1950.1.2.140±144, Ka- Nyanza), purchased E. Degan, NHM bret, fresh water canal, 4 females; Egypt, 1906.4.11.10±19, 1 male, 1 female ovig. 2 NHM 1950.1.2.145±146, 2 females; Suez, females; Entebbe 3700Ј, Capt. C.R.S. Pit- NHM 1913.10.30. 19±20, 1 female; NHM man, NHM 1935.6.26.1±2, 1 male, 1 fe- 1913.10.30. 21±25, 1 male, 3 females ovig., male ovig., 1 female; 17 miles from En- 1 female, 3 juv. tebbe, pres. by Corbat, E.A.F.R.O., NHM Sudan: White Nile, coll. L. Loat, NHM 1958.1.20, 2 females ovig.; Lake Victoria, 1906.6.1, 2 females ovig.; Nil Blanc, envi- Karunga, pres. Acting Commissioner, East rons de Kosti (White Nile surroundings of African Protectorate, NHM 1906.1.6.1±10, Kosti), 01.29, MNHN Na 992, 4 females 20 females ovig.; (Victoria Nyanza) coll. ovig., 1 female; Lac No, con¯uent Nil W.A. Cunnington, NHM 1906.2.12.11±20, Blanc-Bhar el Charal (the con¯uent White 5 males, 18 females ovig., 15 females; NileÐBhar el Charal), 01.29, MNHN Na NHM 1906.2.12.21±25, 1 female ovig., 5 993, 4 females ovig., 1 female; Nil Blanc, females, 6 juv.; West shore, pres. Wood- mare de Malakal, (White Nile, pond of Ma- house Esq., NHM 1911.12.21, 1 female; lakal), coll. Brumpt, 01.29, MNHN Na 994, Jinja sailing club, coll. E.B. Worthington 6 males, 5 females, 11 juv. and Michael Graham, NHM 1929.10.23.1± Uganda: , Butiaba, coll. Ch. 2, 2 females; NHM 1929. 10.23.43±57, Alluaud, 1909, MNHN Na 796, 1 female sample 1, 1 male, 1 female; sample 2, 1 ovig.; North end, coll. R.J. Leiper, NHM female ovig., 1 female; sample 3, 2 males, 1907. 12.18.1±5, 3 males, 1 female ovig.; 4 females, 3 juv.; sample 4, 2 males; sample stn 146, Lacustrine modi®cation Butiaba, 5, 1 male, 2 females; sample 6, 1 male; coll. E.B. Worthington and Michael Gra- sample 7, 1 male; NHM 1929.10.23.58±64, ham, NHM 1929.10.23.3±42, 1 male, 2 fe- 1 male, 1 female ovig., 1 female, 1 juv.; males; Shore, Buhuka, 1 male, 1 female coll. I. Gordon, NHM 1926.VII. 10.113± ovig., 1 juv.; Swamp among Pistia, Tvtora 115, 2 males; Off Jinja, 20 m, NHM camp, Lake Albert, pres. by Corbat, 1964.VII.10.81±82, 2 males, 1 female; Off E.A.F.R.O., NHM 1958.1.20, 18.06.52, 1 Jinja, NHM 1964.VII.10.83±112, 5 males, male, 1 female ovig., 3 females; stn 4, 4 m, 5 females, 5 juv.; Shore, Jinja, NHM on hard bottoms, 1 male, 2 females ovig., 1964.VII.10.113±115, 1 male, 2 females 5 females; Ntoroko camp, Swamp amongst ovig., 3 females. Pistia, 3 males, 10 females ovig., 20 fe- Democratic Republic of Congo: Kain- males; Nolaiga Bay, Lake Albert, 23.03.54, ada, stn 567, near , Cambridge 1 male, 2 females ovig., 2 females; Bukuba, Expedition to the East African Lakes 1930± 50Ј off shore, Lake Albert, 22.03.54, 2 fe- 31, NHM 1934.2.8.1±2, 1 female ovig. males, 3 juv.; Buhuka, 23.03.54, 1 male, 1 Kenya: coll. & pres. Dr. J.O. Young, female ovig., 1 female, 4 juv.; Butiaba Is- NHM 1974.65, 1 female ovig; NHM land, 18.03.54, 1 female; Crocodile Island 1974.66, 6 females ovig., 5 females, 4 juv.; (Central Island), Lake Rudolf, 27.04.56, 1 coll. Alluaud et Jeannnel, 1911, stn 23, Ki- female ovig.; stn 195, Victoria Nile above sumuau (Kisumu) fond de la baie de Kavi- 710 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON

Fig. 2. Caridina nilotica. Female from NHM 1928.8.28.12. a. ®rst pereopod; b. second pereopod; c. third pereopod; d. fourth pereopod; e. ®fth pereopod; f. dactylus of ®fth pereopod; g. ®rst male pleopod; h. endopod of ®rst male pleopod; i. ®rst female pleopod; j. second male pleopod; female k. telson; l. terminal spines of telson; m. uropod; n. uropod diaeresis spinules; o. preanal carina; p. eggs. Scale bars: a±e, g, i, k, m, p ϭ 1 mm; f, h, l, n ϭ 0.2 mm; j ϭ 0.2 mm; o ϭ 0.25 mm. VOLUME 118, NUMBER 4 711 rando, dans une mare, Lake Victoria, times length of basal segment. Anterolateral MNHN Na 780, 1 female ovig. teeth of basal segment 0.1±0.2 times basal Tanzania: Tanganyika, Kirando, Up- segment. 9±12 segments bear aesthetascs. pipe camp, coll. S.R.B. Pask, NHM Antennal scale (Fig. 1c) 3.8±4.0 times as 1928.8.28.12, 3 males, 6 females ovig., 14 long as broad. Mandibles (Fig. 1d) asym- females; Malagarasi, Iragala, pres. by Cor- metrical. Maxillule (Fig. 1e). Maxilla (Fig. bat, E.A.F.R.O, NHM 1958.1.20, coll. R.H. 1f). First maxilliped (Fig. 1g). Second max- Lowe, 2 males, 15 females; Uvinza, near illiped (Fig. 1h). Third maxilliped (Fig. 1i). swamp at the edge of the rapids, 17.09.52, First pereopod (Fig. 2a) ®nger 1.2±1.9 1 male, 3 females ovig., 4 females; Mala- times the palm. Chela 2±3 times as long as garasi swamp pool, 17.09.52, 1 male, 2 fe- broad. Carpus 2±2.6 times as long as broad, males; Iragala, Derris pool, 09.09.52, 3 fe- anteriorly excavated. Second pereopod males; Opuya, coll. R.H. Lowe, 3 males, 9 (Fig. 2b) long and slender, ®nger 1±2 times females ovig., 6 females; Bugomga drain- as long as palm. Chela 2.5±3.0 times as age ditch, coll. P.H. Greenwood, 1 female long as broad. Slender carpus, 4.3±5.6 ovig., 1 female; Lake Rukuwa, lake mar- times as long as broad. Third pereopod gins at the out span of the hotel and swamps (Fig. 2c) dactylus 3.2±4.5 times as long as in the delta of Luika River, NHM broad. Spines on dactylus 7±11 (including 1964.VII.10.116±124, sample 1, 1 male, 5 terminal spines), mostly 9 or 10. Propodus females ovig.; sample 2, grassy margins of 3.5±4.2 times as long as dactylus and 11 or the lake 3 females ovig., 2 females; sample 12 times as long as broad with 13±19 spines 3, below falls, 6 males, 15 females; coll. arranged along inner margin. Carpus 0.5± Mann, NHM 1964.VII.10.132±146, 2 fe- 0.6 times as long as propodus, with small males. spines on inner margin. Merus with 2 large Description.ÐMale and female from spines on posterior margin, 1.7±2 times car- NHM 1928.8.28.12; size of adults ranged pus length. Fourth pereopod (Fig. 2d). Fifth from 18±32 mm. pereopod (Fig. 2e, f): dactylus 4±4.8 times Rostrum (Figs. 1a, 3a±i) usually long, as long as broad with 40±60 spines ar- reaching beyond antennal scale (rarely as ranged in comb-like fashion on inner mar- long as antennal scale). Length of rostrum gin. Propodus 12.0±14.5 times as long as 3.5±6.5 mm, 1±1.3 times as long as cara- broad and 3.5±4.5 times as long as dactylus pace. Dorsal teeth 10±28 arranged proxi- with 11±13 spines arranged along inner mally leaving distinct distal gap, which may margin. Carpus 0.45±0.6 times propodus be smooth or interrupted by one or two length and with small spines along inner teeth (Fig. 3a, d, f). 1±3 apical teeth may margin. Merus 1.4±1.8 times carpus length, be present (Fig. 3d, f, g, h). Post-orbital with 2 large spines and small spines on in- teeth always present, 1±3. Unarmed part of ner margin. Epipods present on ®rst four rostrum 0.4±0.8 times that of armed part. pereopods, two setobranchs on all pereo- Tip of rostrum usually bi®d (Fig. 3a, e, i) pods. but may end acutely (Fig. 3b). Ventral teeth First pleopod of male (Fig. 2g, h), en- 10±28, uniformly arranged from proximal dopod 0.2±0.3 times exopod length. Appen- end up to tip. Rostral formula (1±3) 10±28/ dix interna absent in all specimens exam- 10±28 mostly (1±2) 14±24/13±19. Cara- ined from Port Said, Egypt; Nile near Ma- pace with distinct antennal spine placed at lakal, Sudan; Lakes George, Albert, Kwan- orbital angle. Pterygostomian angle round- ia, Victoria (all Uganda), Tanganyika, and ed. Carapace 3.5±5.5 mm long. Abdominal Rukwa area (Tanzania), (Fig. 4e, m, p±s), somite 6 is 0.5±0.7 times as long as cara- but present in material examined from pace. Antennular peduncle (Fig. 1b) 0.8± Suez, Egypt (Fig. 4j) and Lake Aswan, 0.9 times the carapace. Stylocerite 0.75±0.8 Egypt. However, in samples near Cairo, 712 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON

Fig. 3. Caridina nilotica. Rostral variation. a. Near Cairo, Egypt, NHM 2004.2541±50; b. Giza, Egypt, NHM 1908.4.11.1±5; c. Haremilik Canal, Egypt, NHM 1922.11.22.36±55; d. Malakal, Sudan, MNHN Na 994; e. above Murchinson Falls, Victoria Nile, Uganda, NHM 1929.10.23.3±42; f. stn 146, Butiaba, Lake Albert, Ugan- da, NHM 1929.10.23.3±42; g. , Uganda, NHM 1929.10.23.3±42; h. Ntoroko camp, Lake Albert, Uganda, NHM 1958.1.20; i. Jingia, Lake Victoria, Uganda, NHM 1929.10.23.1±2; variation of telson; j. near Cairo, Egypt, NHM 2004.2541±50; k. Giza, Egypt, NHM 1908.4.11.1±5; l. Haremilik Canal, Egypt, NHM 1922.11.22.36±55; m. Malakal, Sudan, MNHN Na 994; n. above Murchinson Falls, Victoria Nile, Uganda, NHM VOLUME 118, NUMBER 4 713

Giza, Haremilik Canal, Timsha Lagoon, could not be con®rmed. There is no Egyp- and Lake Ismalia (all Egypt) (Fig. 4a±d, f± tian material collected by Roux in Leiden. l) the population is mixed; in some speci- Although the ®gure of Pelias niloticus by mens the interna is absent and in others pre- Roux (1833, ®g. 1) is excellent, it does not sent. First pleopod of female (Fig. 2i), en- give an indication of the variability of char- dopod 0.6±0.7 times as long as exopod. acters within this species. DeMan (1908), Second pleopod of male (Fig. 2j). Gordon (1930, 1933) and Hussein and Ob- Telson (Figs. 2k, 3j±m) tapering distally uid-Allah (1992a, b) have all contributed to 1.1±1.3 times as long as 6th abdominal so- current knowledge with regard to intraspe- mite. Dorsal spines 3±6 pairs (including sub ci®c variation of this Nile species. The ros- terminal spine). 1±3 pairs of short terminal trum ®gured by Roux is longer than the an- spines (mostly 1 pair) with or without me- tennal scale with a dental formula of (2) 13/ dian spine, arranged on posterior margin. 14 and is without subapical teeth. The ob- When more than 1 pair are present, middle servations by De Man (1908) suggested a pairs are shorter than outer spines. Terminal rostrum with a dental formula ranging from spines mostly short and stout. According to (0±3) 18ϩ1±23ϩ1/11±20 with the rostral Gordon (1930), adult specimens from Lake descriptions by Gordon (1930) from the Victoria and Lake Kwania were slender and Nile basin within the range scored by De had a slender telson with slightly longer Man (1908). Figures 1a, 3a±i, represent the slender spines with or without sparse setae rostrum for material examined in the pre- on inner side of the lateral spines and on sent study. The rostrum is usually longer both the margins of the middle spines. than the antennal scale (rarely as long as Uropod (Fig. 2m, n), number of diaeresis the scale) with a proximal arrangement of spinules 7±12 (mostly 11 or 12). Preanal 10±28 teeth (mostly14±24) leaving an api- carina (Fig. 2o) sharp without spines. Num- cal gap which is interrupted by one or two ber of eggs varies from 85 to 140; diameter teeth, and provided with or without 1±3 api- (Fig. 2p) 0.5±0.85 ϫ 0.35±0.55. cal teeth. One to three post-orbital teeth are Remarks.ÐRoux (1833) described Cari- always present. The unarmed part of the dina nilotica (as Pelias niloticus) from the dorsal margin of the rostrum is 0.4±0.8 River Nile in Egypt, but gave no indication times that of the armed part. Between 10 of the precise locality. Additional ®eld data and 28 (typically 13±19) teeth were uni- are not available because the whereabouts formly arranged on the ventral margin, of his type material are unknown. Accord- while the tip of the rostrum was mostly bi- ing to Holthuis (pers. comm.) it is likely ®d (Figs. 1a, 3a, e, i) or ended acutely (Fig. lost. Apparently Roux collected the type 3b). The dental formula (rostrum) of C. nil- material during his expedition with K.A.A. otica including its variations as presented in von HuÈgel, a German nobleman, to Egypt the description of the present study is con- and India, 1831±1833, and the Egyptian sidered to be diagnostic. material was later sold to dealers. There The morphometric measurements of the were indications that Temminck, the direc- body somites and the proportions of the pe- tor of the Leiden Museum in 1836, pur- reopod segments were considered typical chased Indian material collected by Roux for the species. The spines on the dactylus from the dealer Dupont in Paris, but this of the third and ®fth pereopod were consid-

←

1929.10.23.3±42; o. stn 146, Butiaba, Lake Albert, Uganda, NHM 1929.10.23.3±42; p. Lake Kwania, Uganda, NHM NHM 1929.10.23.3±42; q. Ntoroko camp, Lake Albert, Uganda, NHM 1958.1.20; r. Jinja, Lake Victoria, Uganda, NHM 1929.10.23.1±2. Scale bars: a±i ϭ 1 mm; j±r ϭ 0.5 mm. 714 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON

Fig. 4. Caridina nilotica. Examples of variation in the endopod of ®rst male pleopod. a, b. near Cairo, Egypt, NHM 2004.2541±50; c, d. near Giza, Egypt, NHM 1908.4.11.1±5; e. Port Said, Egypt, NHM 1921.4.27.37±42; f, g. Haremilik Canal, Egypt, NHM 1922.11.22.36±55; h, i. Timsha lagoon, Egypt, NHM 1927.11.2.53.72; j. Suez, Egypt, NHM 1913.10.30.21±25; k, l. Lake Ismailia, Egypt, NHM 1927.11.2.73±77; m. Malakal, Sudan, MNHN Na 994; n. above Murchinson Falls, Victoria Nile, Uganda, NHM 1929.10.23.3±42; o. Lake Albert, Uganda, NHM 1907.18.1±5; p. Lake George, Uganda, NHM 1934.28.3±7; q. Lake Kwania, Uganda, NHM VOLUME 118, NUMBER 4 715 ered to be a useful taxonomic character. The pendix interna were recorded. It may be telson was longer than the 6th abdominal so- noted that fresh collections of large samples mite and tapered, with 3±6 pairs of dorsal from local populations in several areas at spines. Asymmetry of the dorsal spines on different times of the year may provide the left and right sides of the telson was not more information concerning this character. pronounced in the present investigation as However, identifying yet another species it was recorded by Hussein & Obuid-Allah based on the presence or absence of appen- (1992a, b), although occasionally one or dix interna seemed unwarranted since the two spines differed on either side. Abnor- other characters fell within the variation ex- mal specimens with regenerating telsons pected for C. nilotica. The number of uro- were not considered. Short, stout, terminal pod diaeresis spinules varied between 7 and spines ranging from 1±3 pairs (typically 1 12 (mostly 10 or 11), and was regarded as pair), with or without a median spine, were another distinguishing character. arranged at the broad tip. When more than 1pair of spines were present, the lateral Caridina bunyonyiensis, new species ones were slightly longer than the inner Figs. 5, 6 ones. The terminal spines were usually Caridina nilotica, Gordon, 1933: 354±357 short and stout. However, in the specimens (part), ®g. 1c. from Lakes Victoria and Kwania, the spines were slender and slightly elongated with the Material examined.ÐUganda: Lake inner margin of the lateral spines and both Bunyonyi, coll. & pres. J. Ford, holotype, the margins of the other spines sparsely plu- NHM 2004.2657, 1 male; paratypes, NHM mose. The different types of telson were 2004.2617±2627, 8 males, 2 females. ®gured (see Fig. 3j±r). A telson with an api- Bufundi, Lake Bunyonyi, coll. E.B. Wor- cal protrusion plus an arrangement of 3 or thington, August 1931, pres. Cambridge more pairs of plumose spines of almost Expedition to the East African Lakes 1930± equal length ®gured by earlier studies (Gor- 31, stn 705, paratypes, NHM 1934.2.8.10, don 1930, Hussein, & Obuid-Allah 1992a) 8 males, 5 females ovig., 12 females; NHM was not considered typical of C. nilotica. 1934.2.8.11, 39 juv.; NHM 1934.2.8.19, 1 However the telson inclusive of the varia- female; stn 707A, paratypes, NHM tions described above is characteristic of the 1934.2.8.40, 9 males, 8 females ovig., 10 Nile species. females, 1 juv.; NHM 1934.2.8.39, 76 juv.; The endopod of ®rst male pleopod pre- ®gured and dissected, NHM 1934.2.8.39± sented some notable variations. The shape 40, 1 male, 1 female; stn 707B, paratypes, of the endopod as well as the presence or NHM 1934.2.8.89, 1 female. absence of appendix interna varied (see Fig. DescriptionÐHolotype, paratype male 4). From the observations of the present and female from NHM 1934.2.8.39±40. study, the absence of the appendix interna Size of adults ranged from 15 to 22 mm. on the endopod seems to be a regular fea- Rostrum (Fig. 5a, b) short, shorter than ture in specimens from the southern regions eye, rarely equal to ®rst segment of anten- of the Nile Basin from Tanganyika north to nular peduncle, but never longer. Length of White Nile at Malakal, Sudan. In the north- rostrum varied from 0.6 to 1 mm, 0.15 to ern basin, specimens with and without ap- 0.23 times as long as carapace. Rostral for-

←

1929.10.23.3±42; r. Lake Victoria, Uganda, NHM 1964.VII.10.81±82; s. Lake Rukwa, Tanzania, NHM 1964.VII.10.116±146; t. grassy lake margins, Lake Rukwa, Tanzania, NHM 1964.VII.10.116±146. Scale bar: 0.2 mm. 716 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON

Fig. 5. Caridina bunyonyiensis. Paratype female from NHM 1934.2.8.39±40. a. lateral view; b. anterior lateral view of carapace; c. antennular peduncle; d. antenna; e. mandibles; f. maxillule; g. maxilla; h. ®rst maxilliped; i. second maxilliped; j. third maxilliped. Scale bars: a ϭ 1 mm; b±j ϭ 0.5 mm. VOLUME 118, NUMBER 4 717 mula always 0/0, occasionally small spine The stout endopod possesses uniform (rarely two) present at tip. Carapace with stalked setae leaving a gap at the inner an- distinct antennal spine at orbital angle. Pter- terior lateral surface. Endopod without ap- ygostomian angle rounded. Carapace 4.0 to pendix interna. First pleopod of female 4.5 mm long. 6th abdominal somite 0.6±0.7 (Fig. 6i), endopod 0.5±0.60 times as long times length of carapace. Antennular pe- as the exopod. Second pleopod of male duncle (Fig. 5c) 0.8±0.9 times carapace (Fig. 6j). length. Stylocerite 0.7±0.8 times length of Telson (Fig. 6k, l): slender and tapering basal segment length. Anterolateral teeth of posteriorly, with 4 or 5 pairs of dorsal basal segment 0.2±0.25 times basal seg- spines (including the subterminal spine). ment. 8 or 9 segments bear aesthetasc. An- Terminal spines are 1±3 pairs with or with- tennal scale (Fig. 5d) 4.0±4.5 times as long out median spine. Telson 1±1.1 times as as broad. Mandibles (Fig. 5e) asymmetrical. long as 6th abdominal somite. Maxillule (Fig. 5f). Maxilla (Fig. 5g). First Uropod (Fig. 6m, n): diaeresis with 7 or maxilliped (Fig. 5h). Second maxilliped 9 spinules. Preanal carina (Fig. 6o) with a (Fig. 5i). Third maxilliped (Fig. 5j). small spine at tip. Number of eggs varied First pereopod (Fig. 6a) ®nger 0.7±1.0 from 55 to 65, diameter (Fig. 6p) 0.7±0.80 times length of palm. Chela stout, 2±2.5 ϫ 0.40±0.50 mm. times as long as broad. Carpus slender, 2± Etymology.ÐThe species is named for 2.3 times as long as broad, with deep ex- Lake Bunyonyi. cavation anteriorly. Second pereopod (Fig. Remarks.ÐCaridina bunyonyiensis is 6b) long and slender, ®nger 1±1.2 times as distinguished by a short, unarmed rostrum long as palm. Chela 2±2.5 times as long as which may be provided with a small tooth broad. Carpus 3±4 times as long as broad. (rarely 2) at tip. The ®gure of Gordon Third pereopod (Fig. 6c) dactylus 3.0±3.8 (1933, Fig. 1c) refers to the occurrence of times as long as broad, bearing 8±9 spines these forms in Lake Bunyonyi: ``In many (including terminal spine). Propodus 3±4 specimens the rostrum does not reach much times as long as dactylus and 10 or 11 times beyond the cornea of the eye''. Caridina as long as broad, with 11±13 spines ar- nilotica has an upwardly turned rostrum, ranged along inner margin. Carpus 0.5±0.6 longer than the antennal scale, and is dif- times length of propodus, with small spines ferent from C. bunyonyiensis with a short along inner margin. Merus with 4 spines on plain rostrum. posterior margin, 1.7±2.0 times length of Caridina bunyonyiensis has a short ®nger carpus. Fourth pereopod (Fig. 6d). Fifth pe- and slender carpus on the ®rst pereopod reopod (Fig. 6e, f) dactylus 4.3±5.0 times with a deep excavation; the dactylus of ®fth as long as broad with 45±55 spines ar- pereopod with ®ne setae. The endopod of ranged in comb like fashion on posterior the ®rst pleopod of the male is short and margin. Dactylus has 2±8 ®ne setae along stout and without appendix interna. Uropod inner and outer margins. Propodus 2.4±3 diaeresis spinules ranged from 7 to 9. The times as long as dactylus, 9±11 times as small spine at the tip of the preanal carina long as broad with 11±13 spines arranged and the smaller number of eggs are features along inner margin. Merus 1.5±1.7 times that distinguish C. bunyonyiensis from C. length of carpus, with 2 large spines on pos- nilotica. terior margin. Carpus with small spines on posterior margin, 0.4±0.6 times length of Caridina gordonae, new species propodus. Epipods present on ®rst four pe- Figs. 7, 8 reopods, two setobranchs on all pereopods. First pleopod of male (Fig. 6g, h), en- Caridina nilotica, Gordon, 1933: 354±357 dopod 0.2±0.25 times length of exopod. (part). 718 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON

Fig. 6. Caridina bunyonyiensis. Paratype female from NHM 1934.2.8.39±40. a. ®rst pereopod; b. second pereopod; c. third pereopod; d. fourth pereopod; e. ®fth pereopod; f. dactylus of ®fth pereopod; g. ®rst male pleopod; h. endopod of ®rst male pleopod; i. ®rst female pleopod; j. second male pleopod; female k. telson; l. terminal spines of telson; m. uropod; n. uropod diaeresis spinules; o. preanal carina; p. eggs. Scale bars: a±e, g, i, k, m, p ϭ 1 mm; f, h, j, l, n ϭ 0.2 mm; o ϭ 0.25 mm. VOLUME 118, NUMBER 4 719

Fig. 7. Caridina gordonae. Paratype female from NHM 1934.2.8.41±42. a. lateral view; b. anterior lateral view of carapace; c. antennular peduncle; d. antennal scale; e. mandibles; f. maxillule; g. maxilla; h. ®rst maxilliped; i. second maxilliped; j. third maxilliped. Scale bar: a, b ϭ 1 mm; c±j ϭ 0.5 mm. 720 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON

Material examined.ÐUganda: Bufundi, as long as broad, almost ¯at anteriorly. Sec- Lake Bunyonyi, coll. E.B. Worthington, ond pereopod (Fig. 8b) long and slender, August 1931, pres. Cambridge Expedition ®nger 0.8±1.0 times as long as palm. Chela to the East African Lakes 1930±31, 2.1±2.5 times as long as broad. Carpus 3.0± 12.08.31, stn 705, holotype, NHM 3.5 times as long as broad. Third pereopod 1934.2.8.9, 1 male; paratypes, NHM (Fig. 8c), dactylus 3.5±4.0 times as long as 1934.2.8.15, 24 males, 9 females ovig., 21 broad, with 8 or 9 spines (including termi- females; NHM 1934.2.8.12, 62 juv., nal spine). Propodus 3.0±3.3 times as long 13.08.31, stn 707A, paratypes, dissected as dactylus, 10±12 times as long as broad and ®gured specimens, NHM 1934.2.8.41± with 11±13 spines arranged along inner 42, 1 male, 1 female ovig.; NHM margin. Carpus 0.5±0.6 times length of pro- 1934.2.8.43, 7 males, 7 females ovig., 17 podus, with small spines along inner mar- males; NHM 1934.2.8.38, 118 juv.; stn gin. Merus with 3 spines on posterior mar- 707B, paratypes, NHM 1934.2.8.90, 2 gin, 1.3±1.8 times length of carpus. Fourth males, 1 female. Lake Bunyoni, coll. & pereopod (Fig. 8d). Fifth pereopod (Fig. 8e, pres. J. Ford, paratypes, NHM 2004.2627± f), dactylus 3.5±4.2 times as long as broad, 2639, 6 males, 1 female ovig., 5 females. with 45±55 spines arranged in comb-like Description.ÐHolotype, paratype male fashion on posterior margin with 2±8 spines and female from NHM 1934.2.8.41±42. arranged along inner margin. Propodus 2.5± Size of adults ranged from 15 to 25 mm. 3.0 times as long as dactylus, 9.0±9.5 times Rostrum (Fig. 7a, b) short and straight, as long as broad with 10±17 spines ar- slightly shorter or equal to eye, rarely ranged along inner margin. Merus 1.6±1.8 st nd reaching 1 or 2 segment of antennular pe- times carpus, with two big spines on pos- duncle, never longer than antennular pedun- terior margin. Carpus with small spines on cle. Length of rostrum 0.75 to 1.0 mm, 0.2± posterior margin, 0.4±0.7 times propodus. 0.23 times as long as carapace; dorsal teeth Epipods present on ®rst four pereopods, 1±13 (mainly 3±7), arranged uniformly al- two setobranchs on all pereopods. most to tip. Occasionally a tooth (rarely First pleopod of male (Fig. 8g, h), en- two) may be present at tip. Post-orbital dopod 0.2±0.25 times the exopod. Endopod teeth typically absent, rarely 1 or 2 may be with uniform stalked setae leaving gap at present. Ventral margin always without inner anterior margin. Endopod without ap- teeth. Rostral formula (0±2) 2±13/0 usually (0±1) 3±7/0. Carapace with distinct anten- pendix interna. First pleopod of female nal spine placed at orbital angle. Pterygos- (Fig. 8i): with endopod 0.5±0.6 times as tomian angle rounded. Carapace 3.9±4.5 long as the exopod. Second pleopod of mm long. Antennular peduncle (Fig. 7c) male (Fig. 8j). 0.7±0.8 times length of carapace. Stylocer- Telson (Fig. 8k, l) slender, tapering at ite 0.6±0.7 times basal segment. Anterolat- posterior end with 5±7 pairs of dorsal eral teeth of basal segment 0.2±0.23 times spines (including subterminal spine); 0.9± basal segment. 12 segments bear aesthe- 1.0 times the length of the 6th abdominal tascs. Antennal scale (Fig. 7d) 4.0±4.5 somite; 1±3 pairs of plain terminal spines times as long as broad. Mandibles (Fig. 7e) with or without median spine present. asymmetrical. Maxillule (Fig. 7f). Maxilla Uropod (Fig. 8m, n), diaeresis spinules (Fig. 7g). First maxilliped (Fig. 7h). Second 8±10. Preanal carina (Fig. 8o) with small maxilliped (Fig. 7i). Third maxilliped (Fig. medial spine, with sharp spine at tip. Num- 7g). ber of eggs varied from 30 to 45, diameter First pereopod (Fig. 8a) ®nger 0.8±0.9 (Fig. 8p) 0.7±0.9 ϫ 0.4±0.5 mm. times length of palm. Chela stout, 1.9±2.3 Etymology.ÐThe species is named after times as long as broad. Carpus 1.6±2 times Dr. Isabella Gordon, as a mark of respect to VOLUME 118, NUMBER 4 721

Fig. 8. Caridina gordonae. Paratype female from NHM 1934.2.8.41±42. a. ®rst pereopod; b. second pereo- pod; c. third pereopod; d. fourth pereopod; e. ®fth pereopod; f. dactylus of ®fth pereopod; g. ®rst male pleopod; h. endopod of ®rst male pleopod; i. ®rst female pleopod; j. second male pleopod; female k. telson; l. terminal spines of telson; m. uropod; n. uropod diaeresis spinules; o. preanal carina; p. eggs. Scale bars: a±e, g, i, k, m, p ϭ 1 mm; f, h, j, l, n ϭ 0.2 mm; o ϭ 0.25 mm. 722 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON her contributions to carcinology, especially 30 juv.; non types, abnormal rostrum, to the African Atyidae. NHM 1934.2.8.45, 2 males, 1 female ovig., Remarks.ÐCaridina gordonae can be 3 females; stn 707B, paratype, NHM readily identi®ed by its short and straight 1934.2.8.88, 1 female. Lake Bunyonyi, rostrum with teeth only on the dorsal mar- coll. & pres. J. Ford, paratypes, NHM gin. The rostrum is slightly shorter than or 2004.2640±2656, 13 males, 1 female ovig., equal to the eye, but rarely reaches the ®rst 2 females. or second segment of the antennular pedun- Description.ÐHolotype, paratype male cle. The rostral tip is plain, or with a small and female from NHM 1934.2.8.9±10. Size forwardly directed tooth (rarely 2 teeth). of adults ranged from 15 to 25 mm. The number of dorsal teeth ranges from 2 Rostrum (Fig. 9a±e) shorter, as long as or to 13, typically 3±7, with 0±2 being post- sometimes fractionally longer than the an- orbital. Gordon (1933), while describing the tennal scale. Length of the rostrum 1.2±3.5 rostral formulae of C. nilotica from Lake mm and 0.6±1.0 times as long as the cara- Bunyonyi, remarked,`` and sometimes the pace; tip usually bi®d or pointed, rarely ventral series is greatly reduced or absent.'' with 3 spines. Dorsal teeth 2±25 (mostly 5± Two of the seven formulae given by Gor- 15), arranged proximally leaving distal gap don (1933), are 1ϩ7ϩ1ϩ1/0 and 0ϩ5ϩ0/0, which may be interrupted by 1 or 2 teeth; which are well within the rostral formula distal unarmed part mostly 0.2±0.5 (rarely for C. gordonae, being (0±2) 1±13/0, typi- to 0.8) times armed part of rostrum. Post- cally (0±1) 3±7/0. orbital teeth absent or present (maximum of Caridina gordonae possesses a robust 2). Ventral teeth varying from 1 to 18, ar- chela on the ®rst pereopod with a short ®n- ranged uniformly from proximal to distal ger, and a carpus almost ¯attened anteriorly. end. Rostral formula (0±2) 2±25/1±18, typ- The preanal carina possesses two spines. ically (0±1) 5±15/5±14. Carapace with dis- The endopod of the ®rst male pleopod is tinct antennal spine, pterygostomian angle short and stout and without appendix rounded. Carapace 3.0±3.5 mm long. Sixth interna. The number of eggs is less than C. abdominal somite 0.6±0.7 times carapace. nilotica, ranging 30±45. Antennular peduncle (Fig. 9f) 0.76 times carapace length; stylocerite 0.55±0.6 times Caridina pseudonilotica, new species as long as basal segment; anterolateral tooth Figs. 9, 10 0.15±0.2 times basal segment, 9±10 seg- ments bear aesthetascs. Antennal scale (Fig. Caridina nilotica, Gordon, 1933: 354±357 9g) 4.2±4.8 times as long as broad. Man- (part). dibles (Fig. 9h) asymmetrical. Maxillule Material examined.ÐUganda: Bufundi, (Fig. 9i). Maxilla (Fig. 9j). First maxilliped Lake Bunyonyi, coll. E.B. Worthington, Au- (Fig. 9k). Second maxilliped (Fig. 9l). gust 1931, pres. Cambridge Expedition to Third maxilliped (Fig. 9m). the East African Lakes 1930±31, 12.08.31; First pereopod (Fig. 10a) ®nger 0.9±1.2 stn 705, holotype, NHM 1934.2.8.8, 1 male; time as long as palm, chela 2.0±2.4 times paratypes, NHM 1934.2.8.13, 12 male, 10 as long as broad, carpus 1.5±1.7 times as females ovig., 13 females 1 juv.; NHM long as broad, almost ¯at anteriorly. Second 1934.2.8.16, 18 juv.; dissected and ®gured pereopod (Fig. 10b) ®nger 1.2±1.5 times as specimens, NHM 1934.2.8.9±10, 1 male, 1 long as palm, chela 2.2±2.7 times as long female ovig.; non types, 3 specimens abnor- as broad, carpus 3.4±4.0 times as long as mal rostrum, NHM 1934.2.8.20, 1 female broad. Third pereopod (Fig. 10c), dactylus ovig., 2 females. 13.08.31; stn 707A, para- 3.0±3.5 times as long as broad with 8±10 types, NHM 1934.2.8.41, 11 males, 16 fe- spines; propodus 3.3±4.0 times as long as males ovig., 9 females; NHM 1934.2.8.42, dactylus, 10±12 times as long as broad with VOLUME 118, NUMBER 4 723

Fig. 9. Caridina pseudonilotica. Paratype female from NHM 1934.2.8.9±10. a. lateral view; rostral variation, NHM 1934.2.8.13, b. female ovig.; c. female; NHM 2004.2640±2656, d. male; e. male; female, f. antennular peduncle; g. antennal scale; h. mandibles; i. maxillule; j. maxilla; k. ®rst maxilliped; l. second maxilliped; m. third maxilliped. Scale bar: a ϭ 1 mm; b±e ϭ 1 mm; f±m ϭ 0.5 mm. 724 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON

Fig. 10. Caridina pseudonilotica. Paratype female from NHM 1934.2.8.9±10. a. ®rst pereopod; b. second pereopod; c. third pereopod; d. fourth pereopod; e. ®fth pereopod; f. dactylus of ®fth pereopod; g. ®rst male pleopod; h. endopod of ®rst male pleopod; i. ®rst female pleopod; j. second male pleopod; female, k. telson; l. terminal spines of telson; m. uropod; n. uropod diaeresis spinules; o. preanal carina; p. eggs. Scale bars: a±e, g, i, k, m, p ϭ 1 mm; f, h, j, l, n ϭ 0.2 mm; o ϭ 0.25 mm. VOLUME 118, NUMBER 4 725

10±13 spines arranged along inner margin; into lower range being (0±2) 2±25/1±18, carpus 0.5 to 0.6 times propodus, with typically (0±1) 5±15/5±14. Postorbital teeth small spines on inner margin; merus with 3 may be present or absent in C. pseudoni- large spines on posterior margin, 1.7±2 lotica whereas they are always present in times carpus. Fourth pereopod (Fig. 10d). C. nilotica. Gordon (1933) referred to the Fifth pereopod (Fig. 10e, f), dactylus 4.0± unique situation of the rostral dentition of 4.2 times as long as broad, 45±50 spines her samples from Lake Bunyonyi: ``There arranged in a comb-like fashion on poste- is a marked tendency towards reduction of rior margin; propodus 2.3±3.0 times as long the dorsal series, so that, in the specimens as dactylus, 10±12 times as long as broad examined, it was most usual for ventral to with 10±13 spines arranged along inner exceed the dorsal number of teeth (in 16 out margin; merus 1.8±2 times carpus length, of 22 specimens; see text-®g. 1a), some- with two large spines on inner margin; car- times the ventral series is greatly reduced pus with small spines on inner margin, 0.4± or absent''. Five of the seven formulae pre- 0.5 times propodus length. Epipods present sented by Gordon (1933) fell in to the range on ®rst four pereopods, two setobranchs on (0±2) 5±19/9±17. This is well within the all pereopods. rostral formula for C. pseudonilotica, noted First pleopod of male (Fig. 10g, h), en- as (0±2) 2±25/1±18 but mostly (0±1) 5±15/ dopod 0.2±0.25 times exopod length. En- 5±14. In C. nilotica the number of dorsal dopod possesses uniform stalked setae leav- and ventral teeth is always above 10. ing gap at inner margin and one long ®ne However, the shape and arrangement of seta protrudes from lower margin. Endopod teeth in the new species resemble C. nilo- without appendix interna. First pleopod of tica. The dorsal teeth are arranged from the female (Fig. 10i), endopod 0.6±0.7 times as proximal end leaving a distal gap. Never- long as exopod. Second pleopod of male theless, the proportion between the un- armed part to the armed part is usually less (Fig. 10j). in C. pseudonilotica, being 0.2±0.5 (rarely Telson (Fig. 10k, l) slender, tapering at to 0.8), while the unarmed part is longer in posterior end, 1.0±1.1 times as long as 6th C. nilotica, being 0.4±0.8 times the armed abdominal somite, with 5±7 pairs of dorsal part. spines (including subterminal spine). Ter- Caridina pseudonilotica possesses a minal spines are 2 or 3 pairs with or without shorter stylocerite, the chela of the ®rst pe- median spine; inner pairs may be sparsely reopod is robust, and the carpus is almost plumose. ¯at anteriorly. The endopod of the ®rst male Uropod (Fig. 10m, n) with 8±10 spinules. pleopod is strong with a short stout endo- Preanal carina (Fig. 10o) with 2 small pod and the preanal carina possesses 2 spines present, one medial, the other at tip. sharp spines. This new species has a fewer Number of eggs varied from 40 to 50, di- eggs (45±55) than C. nilotica (85±140). ϫ ameter (Fig. 10p) 0.7±0.8 0.4±0.5 mm. Even though C. pseudonilotica resembles Etymology.ÐNamed for the resemblance C. nilotica, its shorter rostrum and the re- to C. nilotica with respect to the shape and duction in the number of rostral teeth are arrangement of teeth on the rostrum. distinguishing characters. The unarmed part Remarks.ÐCaridina pseudonilotica is of the rostrum is usually shorter in the new distinguished from C. nilotica by posses- species when compared to that of C. nilo- sion of a rostrum that is shorter, as long as, tica. or sometimes fractionally longer than the antennal scale (Fig. 9a, b). The number of Caridina subventralis, new species dorsal and ventral teeth is as low as 2 and Figs. 11, 12 1, respectively. The dental formula, though Caridina nilotica, Gordon, 1933: 354±357 it overlaps that of C. nilotica, mostly falls (part), Fig 1b. 726 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON

Fig. 11. Caridina subventralis. Paratype female from NHM 1934.2.8.43±44. a. lateral view; b. anterior lateral view of carapace; c. antennular peduncle; d. antenna; e. mandibles; f. maxillule; g. maxilla; h. ®rst maxilliped; i. second maxilliped; j. third maxilliped. Scale bar: a ϭ 1 mm; b±j ϭ 0.5 mm. VOLUME 118, NUMBER 4 727

Material examined.ÐUganda: Bufundi, maxilliped (Fig. 11i).Third maxilliped (Fig. Lake Bunyonyi, coll. E.B. Worthington, 11j). August 1931, pres. Cambridge Expedition First pereopod (Fig. 12a) ®ngers 0.8±1.0 to the East African Lakes 1930±31, times palm length. Chela stout, 2±2.5 times 13.08.31, stn 707A, holotype, NHM as long as broad. Carpus 1.7±1.9 times as 1934.2.8.38, 1 male;12.08.31, stn 705, long as broad, with shallow excavation. paratypes, NHM 1934.2.8.14, 2 males, 4 fe- Second pereopod (Fig. 12b) with ®nger males ovig., 13 females; NHM 1934.2.8.17, 0.9±1.0 times as long as palm. Chela 2.0± 4 juv.; NHM 1934.2.8.18, 2 females ovig.; 2.5 times as long as broad. Carpus 3.0±3.5 13.08.31, stn 707A, paratypes, ®gured and times as long as broad. Third pereopod dissected, NHM 1934.2.8.43±44, 1 male, 1 (Fig. 12c) with dactylus 3.6±4.0 times as female; NHM 1934.2.8.44, 11 males, 11 fe- long as broad, bearing 7±9 spines (includ- males ovig., 15 females; stn 707B, para- ing the terminal spines). Propodus 3.0±3.6 types, NHM 2004.2658 1 female. times as long as dactylus, 10±11 times as Lake Bunyonyi, coll. & pres. J. Ford, long as broad, with 11±13 spines along in- paratypes, NHM 2004.2607±2616, 8 males, ner margin. Carpus 0.5±0.6 times propodus 1 female. length, with small spines along inner mar- Description.ÐHolotype, paratype male gin. Merus with 4 large spines on posterior and female from NHM 1934.2.8.43±44. margin, 1.7±2.0 times carpus length. Fourth Size of adults ranged from 15 to 25 mm. pereopod (Fig. 12e). Fifth pereopod (Fig. Rostrum (Fig. 11a, b): short, straight, 12e, f) with dactylus 4.5±5.0 times as long usually reaching ®rst segment of antennular as broad, with 45±55 spines arranged a peduncle, rarely reaching tip of peduncle, comb-like fashion on inner margin. Propo- never longer than antennular peduncle. dus 2.6±3.0 times as long as dactylus, 11± Length of rostrum 1.3±2.0 mm and 0.4±0.5 12 times as long as broad with 9±13 spines times as long as carapace. Dorsal teeth 2± arranged along inner margin. Merus 1.5±1.7 13, mostly from 5±9, arranged continuously times carpus, with 2 large spines on poste- or in one or two groups in proximal region, rior margin. Carpus with small spines on leaving small distal gap. Post-orbital teeth posterior margin, 0.4±0.5 times propodus. typically absent, but rarely 1 or 2 present. Epipods present on ®rst four pereopods, Ventral teeth 1±10, typically 3±5 always two setobranchs on all pereopods. present, arranged subventrally at distal end. First pleopod of male (Fig. 12g, h) 0.2± Rostral formula (0±2) 2±13/1±10 usually 0.25 times exopod length. Stout endopod (0) 5±9/3±5, with ventral teeth always ar- possesses uniform stalked setae leaving gap ranged on distal curvature. Carapace with at inner margin. Endopod without appendix distinct antennal spine placed at orbital an- interna. First pleopod of female (Fig. 12i) gle. Pterygostomian angle rounded. Cara- endopod 0.5±0.6 times as long as exopod. pace 3.75±4.50 mm long. Antennular pe- Second pleopod of male (Fig. 12j). duncle 0.8±0.9 times carapace length, sixth Telson (Fig. 12k, l) slender, tapering at abdominal somite 0.5±0.6 times the cara- posterior end, with 4±5 pairs of dorsal pace. Antennular peduncle (Fig. 11c) 0.75± spines (including subterminal spine). Tip 0.85 times length of carapace. Stylocerite with 2 or 3 pairs of plain spines, with or 0.7±0.8 times basal segment, anterolateral without a median spine. Telson 1±1.1 times teeth of basal segment 0.2±0.25 times basal 6th abdominal somite. segment, 9 or 10 segments bear aesthetascs. Uropod (Fig. 12m, n) with 7 or 8 spi- Antennal scale (Fig. 11d) 4.0±4.5 times as nules. Preanal carina (Fig. 12o) with small long as broad. Mandibles (Fig. 11e) asym- spine at tip. Number of eggs varied from metrical. Maxillule (Fig. 11f). Maxilla (Fig. 45±60; diameter (Fig. 12p) 0.6±0.7 ϫ 0.49± 11g). First maxilliped (Fig. 11h). Second 0.55 mm. 728 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON

Fig. 12. Caridina subventralis. Paratype female from NHM 1934.2.8.43±44. a. ®rst pereopod; b. second pereopod; c. third pereopod; d. fourth pereopod; e. ®fth pereopod; f. dactylus of ®fth pereopod; g. ®rst male pleopod; h. endopod of ®rst male pleopod; i. ®rst female pleopod; j. second male pleopod; female k. telson; l. terminal spines of telson; m. uropod; n. uropod diaeresis spinules; o. preanal carina; p. eggs. Scale bars: a±e, g, i, k, m, p ϭ 1 mm; f, h, j, l, n ϭ 0.2 mm; o ϭ 0.25 mm. VOLUME 118, NUMBER 4 729

Etymology.ÐThe species is named for 4a) Rostrum with teeth on the dorsal mar- the arrangement of the ventral teeth on the gin only ...... Caridina gordonae rostrum. 4b) Rostrum with teeth on dorsal margin Remarks.ÐCaridina subventralis has a and the ventral teeth arranged sub ter- short and straight rostrum with a subter- minally ...... Caridina subventralis. minal arrangement of the ventral teeth. The Acknowledgments post-orbital teeth range from 0 to 2, but mostly none. The rostral formula is (0±2) We thank Prof. Lipke Holthuis for his 2±13/1±10, usually (0) 5±9/3±5, with ven- support and comments on earlier drafts of tral teeth always arranged on a distal cur- this manuscript. We thank Alain Crosnier vature. and ReÂgis Cleva for arranging loan material While describing the variation in the ros- from the Paris Museum. This study was un- tral dentition of C. nilotica from Lake Bun- dertaken during a visit by the ®rst author to yonyi, Gordon (1933) referred to specimens the Natural History Museum, London. JR with the type of rostrum described for C. acknowledges the Department of Zoology subventralis. She (Gordon, 1933, text-®g. and would especially like to thank Clare 1b) con®rmed the occurrence of this type Valentine for bench space and access to the as common in Lake Bunyonyi: ``Although reference collection. The comments of two again subject to much variation, the type anonymous reviewers are appreciated. represented in text Fig 1.b with a few sub- terminal teeth on the ventral margin is most LITERATURE CITED common.'' Bouvier, E. L. 1925. Recherches sur la morphologie, Caridina subventralis has a subterminal les variations, la distribution geÂographique des arrangement of ventral teeth on the rostrum, crevettes de la famille des AtyideÂs. EncyclopeÂ- a ®rst pereopod with stout carpus with a die Entomologique Paris 4:1±370. shallow anterior excavation, a ®rst male Calman, W. T. 1906. 2. Zoological results of the third Tanganyika expedition. Report on the macru- pleopod with a characteristic endopod, pre- rous Crustacea.ÐProceedings of the Zoological anal carina with one spine, and fewer eggs. Society of London 1906:187±206. All these characters differentiate this spe- . 1928. 28. On the prawns of the family Atyi- cies from C. nilotica. dae from Tanganyika.ÐProceedings of the Zoo- logical Society of London 1928:737±741. De Man, J. G. 1908. On Caridina nilotica (Roux) and Key its varieties.ÐRecords of Indian Museum. Cal- cutta 2:255±283. 1a) Rostrum usually much longer than the Gordon, I. 1930. 30. African freshwater prawns of the antennal scale, rarely equal to but never species Caridina nilotica (Roux) with special shorter than the antennal scale .... reference to Nile Basin.ÐProceedings of the ...... Caridina nilotica Zoological Society of London 1930:33±50. . 1933. Scienti®c results of the Cambridge Ex- 1b) Rostrum shorter, equal to or fraction- pedition to the East African Lakes, 1930±1.Ð ally longer than the antennal scale . . . 2 14. Crustacea Macrura (prawns).ÐJournal of 2a) Rostrum shorter, equal to or sometimes the Linnean Society of London 38:351±362. fractionally longer than the antennal Hickson, S. I. 1888. On a new species of the genus scale ...... Caridina pseudonilotica Atya (A. Wyckii) from Celebes.ÐAnnals and 2b) Rostrum never reaching distal end of Magazine of Natural History, Series 6, 2:357± the antennal scale ...... 3 362, pls 13±14. 3a) Rostrum without teeth on the dorsal Hussein, M. A., & A. H. Obuid-Allah. 1992a. Rede- scription of the freshwater prawn Caridina nil- and ventral margins; one (rarely 2) otica nilotica (Crustacea, Decapoda, Atyidae) tooth may or may not be present at the collected from Egypt. I. External features.Ð tip ...... Caridina bunyonyiensis Journal of the EgyptianÐGerman Society of 3b) Rostrum with teeth on both margins or Zoology, Invertebrate & Parasitology 9:121± on only one margin ...... 4 142. 730 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON

,& . 1992b. Description of the fresh- Roux, P. 1833. Lettre relative a divers Coquilles, Crus- water prawn Caridina nilotica nilotica collected taceÂs. Insectes, Reptiles et Oiseaux, observeÂs en from Egypt. II. Appendages. Journal of the EÂ gypte.ÐAnnales des Sciences Naturelles Paris EgyptianÐGerman Society of Zoology.ÐIn- 28:72±78. vertebrate & Parasitology 9:203±222. Stimpson, W. 1861. Prodromus descriptionis - Johnson, D. S. 1960. Sub-speci®c and infra-speci®c ium evertebratorum, quae in Expeditione ad variation in some freshwater prawns of the Oceanum Paci®cum Septentrionalem, a Repub- Indo-Paci®c. Pp. 259±267 in R. D. Purchon, lica Federata missa, Cadwalaldaro Ringgold et ed., Proceedings of the Centenary and Bicen- Johanne Rodgers Ducibus, observavit et des- tenary Congress of Biology, Singapore, Decem- cripsit. Pars VIII. Crustacea Macrura.ÐPro- ber 2±9, 1958. University of Malaya Press, Sin- ceedings of the Academy of Natural Sciences gapore. of Philadelphia 12[1860]:22±47. . 1963. Distributional and other notes on some fresh-water prawns (Atyidae and Palaemonidae) Woltereck, R. 1942. Untersuchungen an Atyiden (De- mainly from Indo-West Paci®c region.ÐBulle- capoda) von Belgisch Kongo, mit besonderer tin of the National Museum of Singapore 32:5± BeruÈcksichtigung der RassenÐund Artbil- 30. dungsfrage.ÐRevue de Zoologie et de Bota- Milne Edwards, H. 1837. Histoire naturelle naturelle nique Africaines, Bruxelles 36:229±328. des CrustaceÂs, comprenant l'anatomie, la phy- siologie et la classi®cation de ces animaux. Par- is, Librairie de Roret. 2:1±532. Associate Editor: Christopher B.Boyko