PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON 113(4):931-944. 2000. Freshwater shrimps of the genus Caridina H. Milne Edwards (Crustacea: Decapoda: Atyidae) from Myanmar Yixiong Cai and Peter K. L. Ng Department ofBiological Sciences, National University of Singapore, Lower Kent Ridge Road, Singapore 119260, Republic of Singapore — Abstract. Five species of freshv^^ater shrimps of the genus Caridina H. Milne Edwards, 1837 are recognised from Myanmar. Of these, three are de- C scribed as new: C. williamsi, C. rangoona and burmensis. Caridina annan- dalei Kemp, 1918, a species not reported since its original description, is re- C diagnosed and figured in detail. The status of weberi prox. var. sumatrensis De Man, 1892 is discussed. The atyid fauna of Myanmar (formerly Genus Caridina H. Milne Edwards, 1837 Burma, Fig. 1) is very poorly studied, and Caridina annandalei Kemp, 1918 until now, only two species of Caridina H. Figs. 2, 3 Milne Edwards, 1837, had been reported, namely C. annandalei Kemp, 1918, and Caridina annandalei Kemp, 1918: 96, pi. "C weberi prox. var. sumatrensis De Man, 25 (type locality: Inle Lake, Shan State, Myanmar) 1892" (Kemp 1918). Recently, the authors — had an opportunity to examine several col- Material examined. 14 specimens (3 ovig. females), syntypes (MNHN-Na663), lections of these shrimps in the Swedish Museum ofNatural History, Paris Museum, Inle Lake, Shan State, Myanmar, exchanged from Calcutta (Indian Museum), entry and Raffles Museum of Singapore. Not sur- no. 41-1921, through S. Kemp; 4 ovig. fe- prisingly, much of this material represents mm males, cl 3.8-4.3 (ZRC.1999.2009), new species. 20°34.87'N, 96°06.33'E, Inle Lake at Mine lecTthioenspraensdendtispcaupsseersrtehpeorsttsatousnotfhe"sCe cwoel-- T26haFuekbca1n9a9l9,;Sh4amnalSteast,e,clMy2a.n5-m2a.r7,mpmH,7.162, fboerriwvhairc.hprnoox.spseucmiamternenssairseDaevaiMlaanbl,e.1A89t2o"- f3e.m2a-l3e.s5, mclm2.5(-3S.M7NmHm,13250o4vi)g,. IfnelmealeLsa,kec,l tal of five species are now recognised from mainly west shore, Salween River drainage, Myanmar, of which three are described as Nyaung Shwe, Shan State, Myanmar, leg. new. S. O. Kullander, Fang Fang, T. R. Roberts, Specimens are depositedintheZoological 26 Feb 1994; 2 ovig. females, cl 2.5-3.0 Reference Collection, Raffles Museum of mm (SMNH 13506), Inle Lake, west mar- Biodiversity Research, National University gin, just south of Khaung Taing, Salween of Singapore, Singapore (ZRC); Swedish River drainage, Nyaung Shwe, Shan State, Museum of Natural History, Stockholm, Myanmar, leg. S. O. Kullander, Fang Fang, Sweden (SMNH); and Museum National 27 Feb. 1994; 1 ovig. female, cl 3.9 mm d'Historie Naturelle, Paris, France (MNHN). (SMNH 13507), SOK 94-007B, Inle Lake, The abbreviation cl is used for carapace Inlet canal to Nyaung Shwe, Salween River length, measured from the postorbital mar- drainage, Nyaung Shwe State, Shan, Myan- gin to the posterior dorsal margin ofthe car- mar, leg. S. O. Kullander, Fang Fang, T. R. apace. Roberts, 1 Mar 1994; 1 female, cl 3.4 mm. 932 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OFWASHINGTON China Andaman En' 92" 94"E t\ '"':^ Fig. L Map ofMyanmar, showing the drainage and collection sites. VOLUME 113, NUMBER 4 933 19 juv. (SMNH 13903), Inle Lake, Trung- Recent collections from Myanmar seem to do, southern Shan State, Myanmar, at 900 show that this species is indeed endemic to m, leg. Malaise—, 12 Sept 1934. the Inle Lake basin. When Kemp (1918) de- Diagnosis. Rostrum (Figs. 2A, 3A) scribed C. annandelai, he noted that it is convex, with tip slightly upturned, reaching allied to C. excavata Kemp, 1913, and C. to end of second segment of antennular pe- hodgarti Kemp, 1913, both from Assam in duncle, or slightly beyond it; rostral for- northeastern India, based on the absence of mula: 2-4 (mode 3) + 12-21/2-6 (mode 2- an epipod on the fourth pereiopod. This 4); antennal spine sharply pointed, placed character is, in fact, shared by many other below lower orbital angle, pterygostomian South East Asian Caridina species, namely, C margin broadly rounded; telson (Figs. 2B, C. laevis Heller, 1862, from Java, exca- C) not terminating in projection, with 5 vatoides Johnson, 1961, from Peninsular pairs of distal spines, lateral pair of distal Malaysia and C. fecunda J. Roux, 1911, spines subequal to intermediates exceptme- from Irian Jaya, Indonesia. Caridina an- C dian pair only half length of lateral pair; nandalei, however, is very differentfrom pre-anal carina (Fig. 2D) lacking spine; an- excavata and C. hodgartiby its much short- tennular peduncle 0.85 times as long as car- er rostrum which never reaches the end of apace, stylocerite 0.8 times length of basal the antennular peduncle (vs. distinctly segment ofanteimularpeduncle; scaphocer- reaching beyond the end of antennular pe- C ite (Fig. 2E) 3.5 times as long as wide; epi- duncle in excavata, and beyond the sca- pods on first 3 pereiopods only; carpus of phocerite in C. hodgarti (cf. Kemp 1913)). first pereiopod (Figs. 2F, 3B) 3.0-3.4 times With regards to the short rostrum, the slen- as long as high, chela slightly longer than der first two pereiopods and the large egg carpus, 2.3 times as long as broad, fingers size, C. annandalei is perhaps most similar distinctly longer than palm; carpus of sec- to C. laevis (cf. Heller 1862, Kemp 1918b, Bouvier 1925), but can be distinguished ond pereiopod (Figs. 2G, 3C) 7.5-8.0 times as long as high, chela shorter than carpus, from it by the form of the rostrum, which is convex and sloping (vs. sigmoid in C. chela 3.4 times as long as broad, fingers 1.6 laevis), and the fifth pereiopod having few- times as long as palm; propodus of third er spinules (44-68 vs. 90-100 in C. laevis). pereiopod (Figs. 3D, E) 2.7-3.2 times as Caridina annandalei differs from C. exca- long as dactylus, dactylus 4.6 times as long vatoides (cf. Johnson 1961) by its more as wide, with 8-12 spines on flexormargin; elongated antennular peduncle (ratio of the propodus of fifth pereiopods (Figs. 3F, G) peduncle to carapace length 0.85 vs. 0.64 2.2-2.5 times as long as dactylus, dactylus in C. excavatoides); more spinules on uro- 4.5 times as long as broad, with 44-68 spi- podal diaeresis (15 vs. 12-13); and larger nules on flexor margin; endopod of male egg size (0.55-0.70 to 0.90-1.05 mm vs. first pleopod (Fig. 2H) sub-rectangular, 2.1 0.48 to 0.78 mm). It can also be easily sep- times as long as wide; appendix interna of arated from C. fecunda (cf. Roux 1911, male second pleopod (Fig. 21) reaching to Bouvier 1925) by the proportionally shorter 0.8 times length of appendix masculina; rostrum; the larger number of spinules on uropodal diaeresis (Fig. 2J) with 15 spi- the dactylus of the third pereiopod (8-12 nules. Egg si—ze 0.55-0.70 to 0.90-1.05 min. vs. 7-8) and fifth pereiopod (44-68 vs. 35- Habitats. Caridina annandalei was 40); and the larger egg size (0.55-0.70 to abundant among green weeds in or near 0.90-1.05 mm vs. 0.50 to 0.80 mm). Inle Lake. — Distribution. Known only from the Inle Caridina williamsi, new species Lake basin —in central Myanmar. Figs.—4, 5 Remarks. Caridina annandalei, had not Material examined. Holotype: ovig. fe- mm been reported since its original description. male, cl 4.4 (ZRC.1999.2040), 934 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON Fig. 2. Cahdina annandalei Kemp, 1918. A, cephalothorax andcephalicappendages; lateralview; B,telson; C, distal part oftelson; D, preanal carina; E, scaphocerite; F, first pereiopod; G. second pereiopod; H, endopod ofmale first pleopod; 1, appendix masculina ofmale second pleopod; J, uropodal diaeresis. Scales: A = 2 mm; B, D, E, F G = 1 mm; C, H, I, J = 0.2 mm. (A-G, J, ovig, female, cl 4.3 mm, Inle Lake, central Myanmar, ZRC, 1999.2009; H, I, male, cl. 2.7 mm Inle Lake, central Myanmar, SMNH 13504) VOLUME 113, NUMBER 4 935 Fig. 3. Caridina annandalei Kemp, 1918; ovig. female, cl 3.7 mm, central Myanmar, SMNH 13903. A, cephalothoraxandcephalicappendages,lateral view; B, firstpereiopod;C, secondpereiopod;D,thirdpereiopod; E, dactylus ofthird pereiopod; F, fifth pereiopod; G, dactylus offifth pereiopod. Scales: A, D, F = 1 mm; B, C = 0.5 mm; E, G = 0.2 mm. 936 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON 17°48.11'N, 96°09.20'E, Balar stream, 12 4D) broadly rounded, upper lacinia elon- km Yangon to Mandalay highway, Htauk gate, with many distinct teeth on inner mar- Kyant, Yangon State, Myanmar. Paratypes: gin, palp slender. Upper endites of maxilla 7 males, cl 1.9-2.2 mm, 8 females, cl 2.8- (Fig. 4E) subdivided, palp short, scaphog- mm 4.0 nmi, 10 ovig. females, cl 3.7-4.2 nathite tapering posteriorly with some long, (ZRC.1999.2041-2059), same data as ho- curved setae at posterior and end. Palp of mm lotype. Others: 18 spec, cl 3.3-4.3 first maxilliped (Fig. 4F) broadly triangular. (ZRC.1999.2060), 17°09.97'N, 96°09.20'E, Second maxilliped (Fig. 4G) typical of the Win Paw Hta river, near border between genus. Third maxilliped (Fig. 4H) reaching Pegu (Bago) and Yangon, and from fish- to end of second segment of antennular pe- foUc, Yangon State, Myanmar; 2 females, cl duncle, with ultimate segment shorter than 2.9-3.0 mm, 1 ovig. female, cl 4.8 mm, penultimate segment. (ZRC.1999.2061), 20°34.87'N, 96°06.33'E, Epipods on first 4 pereiopods. First pe- Inle Lake at Mine Thauk canal, Shan State, reiopod (Fig. 41) reaching to end of basal Myanmar; 6 males, cl. 2.1-2.6 mm, 5 fe- segment of antennular peduncle, merus 3.0 males, cl. 2.3-2.5 mm, 20 juv., Yangon times as long as broad, as long as carpus; (SMNH 13517).— carpus excavated anteriorly, shorter than Description. Rostrum (Figs. 4A, B; chela, 2.3 times as long as high; chela 2.4 5A) narrow, slender, straight or slightly up- times as long as broad; fingers 1.3 times as turned at distal one third, longer than car- long as palm. Second pereiopod (Fig. 4J) apace, reaching beyond end of scaphoceri- reaching end of second segment of anten- te; armed with numerous teeth throughout nular peduncle, merus shorter than carpus, dorsal margin, with 4-9 teeth at middle of 5.0 times as long as broad; carpus 1.3 times ventral margin; formula: 2-3 + 23-30/4-9 as long as chela, 6.0 times as long as high; (mode 5-6). Antennal spine situated below chela 3.0 times as long as broad; fingers 1.4 sub-orbital angle. Pterygostonian angle times as long as palm. Third pereiopod rounded. (Fig. 5F, G) reaching end of scaphocerite, Sixth abdominal somite 0.65 times as propodus slightly shorter than merus, 13 long as carapace, 2.0 times as long as fifth times as long as broad, 4.0 times as long as somite, slightly shorter than telson. Telson dactylus; dactylus 4.0 times as long as wide (Figs. 5B, C) 3.0 times as long as wide, not (spines included), with 8 or 9 accessory terminating in a projection, with 4 pairs of spines on flexor margin. Fifth pereiopod dorsal and 1 pair of dorsolateral spinules; (Fig. 5H, 1) reaching end ofsecondsegment distal margin with 4 pairs of spinules, lat- of antennular peduncle, propodus distinctly eral pair of spine longer than intermediate longer than merus, 13 times as long as pairs of spiniform setae, sublateral pair broad, 3.1 times as long as dactylus; dac- shortest. Preanal carina broadly rounded, tylus 4.0 times as long as wide, with 37 or lacking spine (Fig. 5D). 38 spinules on its flexor margin. Endopod Eyes well developed. Antennular pedun- of male first pleopod (Fig. 5J) triangular, cle 0.85 to 1.0 times as long as carapace; 0.25 times length ofexopod, with appendix basal segment of antennular peduncle lon- interna strongly curved inwards. Appendix ger than sum of second and third segment masculina of male second pleopod (Fig. length. Styloceritereaching 0.8 times length 5K) half length of endopod, appendix of basal segment of antennular peduncle. interna reaching distal one-third of appen- Scaphocerite (Fig. 5E) 3.5 times as long as dix masculina. wide. Uropodal diaeresis (Fig. 5L) with 9 or 10 Incisor process of mandible (Fig. 4C) movable spinules. Egg size 0.75-0.85 to mm ending in irregular teeth, molar process 0.45-0.6 — in diameter. truncated. Lower lacinia of maxillula (Fig. Habitat. Caridina williamsi, new spe- VOLUME NUMBER 113, 4 937 pod; J, second p„ei„ „!'sTa^;:"a'B ITl'-'c^D'fT T'o?!"-?'h^f""""^ '' """"''' 938 PROCEEDINGS OFTHE BIOLOGICAL SOCIETY OF WASHINGTON Fig. 5. Caridina williamsi, new species. A, cephalothorax and cephalic appendages; lateral view; B, telson; C, distal part oftelson; D, preanal carina; E, scaphocerite; F, third pereiopod; G, dactylus ofthird pereiopod; H, fifth pereiopod; I, dactylus of fifth pereiopod; J, endopod ofmale first pleopod; K, appendix masculina ofmale second pleopod; L, uropodal diaeresis. Scales: A = 2 mm; B, E, F, H = 1 mm; C, G, I, J, K, L = 0.2 mm; D = 0.5 mm. (A-I, L, ovig. femal, cl. 3.7 mm, paratype; J, K, male, cl 2.2 mm, paratype, ZRC.1999.2042-2043, Htauk Kyant, Yangon State, Myanmar) VOLUME 113, NUMBER 4 939 cies, was collected from water plants along Yangon State, Myanmar; 12 females, cl 1.6- the edges and on the bottom of water bod- 2.0 mm (SMNH 13902), Hlaing Lake, Kaw- ies. — kareik, near Mo—ulmein, southern Myanmar. Etymology. Caridina williamsi, is Description. Rostrum (Fig 6A) short, named after the late Dr. Austin B. Williams, reaching near end of second segment ofan- an outstanding zoologist, Systematics Lab- tennular peduncle; dorsal margin slightly oratory National Marine Fisheries Service, sloping down, tip slender, acutely pointed, National Museum of Natural History, depressed, rostral formula: 4-6 (mode 4—5) Smithsonian Institution, Washington, who + 10-16 (mode 13-15)/2-5 (mode 3-4). contributed immensely to ourknowledge of Antennal spine situated below sub-orbital the Caridea. angle. Pterygostomlan margin sub-rectan- — Remarks. In the form of the rostrum gular. and large egg size, Caridina williamsi, new Sixth abdominal somite 0.55 times as species, is remarkably close to Caridina long as carapace, 1.9 times as long as fifth & chauhani Chopra Tiwari, 1949, fromPat- somite, slightly shorter than telson. Telson na, northern India. The new species, how- (Figs. 6B, C) 3.3 times as long as wide, not ever, can be distinguished by having four to terminating in a projection, with 4 pairs of nine ventral teeth (mode 5-6) (vs. 4-14 dorsal spinules generally (third pair with C (mode 7-13) in chauhani); the dactylus only left spine, right one absent in a para- of third pereiopod with eight or nine spines type female) and 1 pair of dorsolateral spi- C (vs. five to six in chauhani); and the nules; distal margin armed with 4 pairs of larger egg size: 0.75-0.85 X 0.45-0.6 mm spinules generally (7 spinules in a paratype in diameter (vs. 0.62-0.69 X 0.36-0.40 mm female), lateral pair of spine longer than in- C in chauhani). termediate pairs ofspine, medianpair short- Caridina chauhani was originally de- est. Preanal carina (Fig. 6D) broadly round- scribed as Caridina nilotica var. chauhani. ed, unarmed. Caridina nilotica (P. Roux, 1833), and its Eyes well developed. Antennular pedun- allied species (see De Man 1892, 1908; cle 0.80 to 0.85 times as long as carapace; Bouvier 1925), however, have at least some basal segment of antennular peduncle lon- distinct separated sub-apical teeth on dorsal ger than combined length of second and rostral margin, a character absent in C. n. third segments. Stylocerite reaching 0.8 chauhani. Caridina chauhani is thus, re- times length ofbasal segment ofantennular garded here as a distinct species. peduncle. Scaphocerite (Fig. 6E) 4 times as long as wide. Caridina rangoona, new species First maxilliped (Fig. 6F) with palp end- Fig. 6 ing in finger-like structure; rest of mouth- — part similar to C. williamsi, new species. Material examined. Holotype: ovig. fe- Third maxilliped reaching to end of basal mm male, cl 3.5 (ZRC. 1999.2010), segment of antennular peduncle, with ulti- 17°09.97'N, 96°99.20'E, Win Paw Hta Riv- mate segment slightly shorter than penulti- er, near border between Pegu (Bago) and mate segment. Yangon, Yangon State, Myanmar. Paratypes: Epipods present on first 4 pereiopods. 13 females, cl 2.6-3.3 mm, 8 ovig. females, First pereiopod (Fig. 6G) reaching near end cl 2.6-3.6 mm, 7 juv. (ZRC.1999.2011- of basal segment of antennular peduncle, 2038), data same as holotype. Others: 2 fe- chela 2.2 times as long as broad; fingers 1.5 males, cl 3.1 mm, 3 ovig. females, cl 3.5- times as long as palm; carpus excavated an- mm 3.9 (ZRC.1999.2039), 17°48.11'N, teriorly, slightly shorter than chela, 2.3 96°09.20'E, Balar stream, 12 km from Yan- times as long as hight; merus 2.3 times as gon to Mandalay highway, Htauk Kyant, long as broad; ischium as long as merus. 940 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OFWASHINGTON Second pereiopod (Fig. 6H) reaching endof size (0.30-0.40 X 0.60-0.70 mm in C. ran- second segment of antennular peduncle, goona vs. 0.44-0.54 X 0.70-0.80 mm in C merus as long as ischium, shorter than car- temasek). In the shape ofthe rostrum, C. pus, 4.4 times as long as broad; carpus 1.6 rangoona is morphologically closest to a times as long as merus, 1.2 times as long Vietnamese species, C. clinata Cai, Nguy- & as chela, 6.3 times as long as high; chela en, Ng, 1999, but can be distinguished 3.5 times as long as broad; fingers 1.5 times from the latter (cf. Cai et al. 1999) by the as long as palm. Third pereiopod (Figs. 61, fewer and shorter distal setae on the telson J) reaching end ofantennularpeduncle,pro- (Cai et al. 1999: figs. 2A, 6C); the longer podus shorter than merus, 13 times as long carpus of first pereiopod (2.2 times as long as broad, 3.4 times as long as dactylus; dac- as high vs. 1.5 times in C. clinata); the lon- tylus 4.3 times as long as wide (spines in- ger finger of the first pereiopod (1.5 times C cluded), with 8 or 9 accessory spines on its as long as palm vs. shorter, subequal in flexor margin. Fifth pereiopod (Figs. 6K, L) clinata); the larger number of spinules on reaching end of second segment of anten- the dactylus of the fifth pereiopod (65-67 nular peduncle, propodus distinctly longer vs. 45-49) and the much smaller egg size than merus, 11 times as long as broad, 2.5 (0.30-0.40 X 0.60-0.70 mm vs. 0.60-0.75 times as long as dactylus; dactylus slender, X 1.10-1.15 mm in C clinata). 5.0 times as long as wide, with 65-67 spi- nules on flexor margin. Caridina burmensis, new species Uropodal diaeresis (Fig. 6M) with 15 or Fig. 7 16 movable spinules. Egg size 0.60-0.70 to — mm 0.31-0.40 — in diameter. Material examined. Holotype: female, Habitat. Specimens of Caridina ran- cl 3.7 mm (SMNH 13901), Myitkyina, goona, new species, were collected from Myanmar, leg.—Malaise, 6 Mar 1934. water plants along edges and on the bottom Description. Rostrum (Fig. 7A) short, C of water bodies, together with williamsi, straight, narrow, reaching to end of second new species (H—. H. Tan, pers. comm.). segment of antennular peduncle, dorsal Etymology. Caridina rangoona, is margin convex and sloping ventrad anteri- named after the type locality. Rangoon is orly, with teeth more closely placed poste- the old name for Yangon, the capital of riorly than anteriorly; ventral margin hori- Myanmar. — zontal, with small teeth; rostral formula: 3 Remarks. In rostral shape, rostral for- -I- 11/4. Antennal spine placed below sub- mula, and slender pereiopods, C. rangoona orbital angle; pterygostomian margin is most similar to C. temasek Choy & Ng, rounded. 1991, originally described from Singapore, Abdomen with sixth somite 0.58 times as but has since been found from many parts long as carapace, 1.5 times as long as fifth of Peninsular Malaysia (unpublished data). somite, slightly shorter than telson. Telson Caridina rangoona, however, differs by its (Fig. 7B, C) slightly longer than sixth so- proportionally broader chela (2.2 times as mite, tapering posteriorly, ending in round- long as broad vs. 2.4-2.5 in C. temasek); ed margin, 1 pair of dorso-lateral spines the length of ischium in first pereiopods (as near distal end; 3 pairs of spiniform setae C long as merus in rangoona vs. distinc- on distal margin, lateral pair longer than in- tively shorter than the merus in C. tema- termediate pairs; preanal carina (Fig. 7D) sek); the ratio of propodus to dactylus of with a spine. C fifth pereiopod (2.5 in rangoona vs. 2.6- Eyes well developed. Antennular pedun- C 3.0 in temasek); the smaller number of cle 0.8 times as long as carapace; basal seg- spinules on the dactylus of the fifth pereio- ment slightly longer than half of peduncle, pod (55-65 vs. 65-75) and the smaller egg third segment shortest; stylocerite reaching