Caridina woltereckae Cai, Wowor & Choy, 2009

Rintelen, Kristina von & Cai, Yixiong, 2009, Radiation Of Endemic Species Flocks In Ancient Lakes: Systematic Revision Of The Freshwater Shrimp Caridina H. Milne Edwards, 1837 (Crustacea: Decapoda: Atyidae) From The Ancient Lakes Of Sulawesi, Indonesia, With The Description Of Eight New Species, Raffles Bulletin of Zoology 57 (2), pp. 343-452 : 420-424

Caridina woltereckae Cai, Wowor & Choy, 2009

( Figs. 46–47 ; Table 17)

Caridina woltereckae Cai et al., 2009: 19 , Fig. 3 (type locality: Lake Towuti, Cape Larona, near Sungai [River] Larona outlet, rocky coast with white sand substrate).

Caridina sp.2 – von Rintelen et al., 2007b: 262, fig. 2b.

Material examined. – Lake Towuti: 28 ex. ( MZB Cru 1828, n=10 and few juveniles; ZMB 29037, n=18, some SEM material), west shore, at entrance to outlet bay, Cape Larona, 02°48.43'S, 121°24.75'E, loc. 73-03, ( MZB) on mixed substrate, ( ZMB) on rocks, coll. K . & T. von Rintelen , 8 Oct.2003 ; 24 ex. ( MZB Cru 1829, n=12; ZMB 29044, n=12, some SEM material), north shore, bay east of Cape Bintu, 02°39.48'S, 121°33.25'E, loc. 68-03, on rocks, coll. K . & T. von Rintelen , 26 Sep.2003 ; 13 ex. ( MZB Cru 1830, n=6; ZMB 29052, n=7, some SEM material), Loeha Island, west shore, 02°45.5'S, 121°31.06'E, loc. 95-03, on rocks, coll. K . & T. von Rintelen , 4 Oct.2003 ; 13 ex. ( MZB Cru 1831, n=7; ZMB 29106, n=6, some SEM material), southwest shore, west of Cape Tetetu, 02°54.13'S, 121°23.78'E, loc. 76-03, on rocks, coll. K . & T. von Rintelen , 28 Sep.2003 ; 4 ex. ( ZMB 29144), west shore, south of Cape Timbalo , 02°42.91'S, 121°26.78'E, loc. 94-03, on rocks, coll. K . & T. von Rintelen , 4 Oct.2003 ; 7 ex. ( ZMB 29145), Loeha Island , north shore, 02°45.64'S, 121°34.32'E, loc. 97-03, on rocks, coll. K . & T. von Rintelen , 4 Oct.2003 ; 21 ex. ( MZB Cru 1832, n,=9; ZMB 29146, n=12), north shore, 02°38.56'S, 121°27.82'E, loc. 66-03, on rocks, coll. K . & T. von Rintelen , 26 Sep.2003 ; 13 ex. ( MZB Cru 1833, n=6; ZMB 29147, n=7, some SEM material), north shore, at cape, 02°39.38'S, 121°29.73'E, loc. 67-03, on rocks in deeper water, coll. K . & T. von Rintelen , 26 Sep.2003 ; 2 ex. ( ZMB 29148, n=2 and few juveniles, some SEM material), north shore, west of Cape Manu , 02°41.67'S, 121°36.85'E, loc. 69-03, on rocks in deeper water, coll. K . & T. von Rintelen , 27 Sep.2003 ; 1 ex. ( ZMB 29149, n=1 and few juveniles), west shore, north of Cape Wasupute , 02°46.9'S, 121°27.94'E, loc. 78-03, on rocks, coll. K . & T. von Rintelen , 28 Sep.2003 ; 3 ex. ( ZMB 29151), east shore, south of Cape Tomeraka , 02°44.47'S, 121°37.53'E, loc. 70-03, on rocks, coll. K . & T. von Rintelen , 27 Sep.2003 ; 1 ex. ( ZMB 29310, n=1, some SEM material), west shore, north of Cape Sioloya , 02°50.386'S, 121°26.026'E, loc. 03-05, on rocks, coll. Y. Cai, K . & T. von Rintelen , 3 Jan.2005 ; 4 ex. ( ZMB 29331), west shore, northeast shore, at Cape Noote , 02°39.751'S, 121°39.195'E, loc. 117-04, on rocks in deeper water, coll. K . & T. von Rintelen , 28 Jul.2004 ; 13 ex. ( MZB Cru 1834, n=7; ZMB 29332, n=6), Cape Bakara, 02°40.771'S, 121°26.11'E, loc. 144-04, on rocks in deeper water, coll. K . & T. von Rintelen , 26 Jul.2004 ; 3 ex. ( ZMB 29333), west shore, outlet bay, east of Cape Kombe , 02°48.08'S, 121°23.05'E, loc. 53-03, on rocks, coll. K . & T. von Rintelen , 21 Sep.2003 ; 4 ex. ( ZMB 29334), west shore, west of Cape Timbalo , 02°42.631'S, 121°26.389'E, loc. 145-04, on rocks, coll. K . & T. von Rintelen , 26 Jul.2004 .

Description. – Carapace length 2.4-3.8 mm (n=26). Rostrum ( Fig. 47A ; Table 17) long, reaching beyond end of scaphocerite, 1.0-1.6 times as long as carapace (n=20), armed dorsally with 13-22 teeth (including 3-4 teeth posterior to orbital margin), anterior less densely spaced, armed ventrally with 3-13 teeth. Antennal spine situated below inferior orbital angle. Pterygostomial angle broadly rounded. Eyes well developed, anterior end 0.5-0.6 times length of basal segment of antennular peduncle (n=5). Antennular peduncle 0.9-1.0 times as long as carapace (n=5), second segment 2.0-2.3 times length of third segment, third segment 0.3 times length of basal segment. Stylocerite reaching 0.9-1.0 times length of basal segment of antennular peduncle (n=5). Scaphocerite ( Fig. 47B ) 4.7-5.6 times as long as wide (n=5).

Sixth abdominal somite 0.6-0.9 times length of carapace (n=26), 1.5-1.8 times as long as fifth somite (n=20), 0.9 times length of telson (n=7). Telson ( Fig. 47E,H ) 3.3- 3.9 times as long as wide (n=5), distal margin rounded, without projection, with 3-4 pairs of spinules and 1 pair of dorsolateral spinules; distal end with 4 pairs of spines, lateral pair distinctly longer than intermediate pairs, median pair not always shortest. Preanal carina ( Fig. 47C ) rounded, without a spine. Uropodal diaeresis ( Fig. 47D ) with 11-13 movable spinules (n=5).

5 pairs of pleurobranchs well developed; 3 pairs of arthrobranchs, 2 on third maxillipeds, with second pair strongly reduced in size, 1 pair on first pereiopod; 1 pair of podobranchs on second maxilliped reduced strongly to a laminate form. Epipods only present on first pereiopod. Mouthparts as described by Cai et al. (2009).

Chela and carpus of first pereiopod distinctly stouter and broader than chela and carpus of second pereiopod ( Fig. 47 M-O); chela of first pereiopod 2.0-2.5 times as long as wide (n=20), 1.2-1.5 times length of carpus (n=26); tips of fingers rounded, without hooks; dactylus 1.0-1.5 times as long as palm (n=6); carpus 2.1-2.9 times as long as wide (n=20), 1.2-1.3 times length of merus (n=5). Chela of second cl (mm) 2.4-3.8 2.8 ± 0.3 2.8 26 rl / cl 1.0-1.6 1.3 ± 0.2 1.3 20 n dorsal rostral teeth 13-22 18 ± 2 19 26 n ventral rostral teeth 3-13 8 ± 2 7 26 abds6 / cl 0.6-0.9 0.6 ± 0.1 0.6 26 abds6 / abds5 1.5-1.8 1.6 ± 0.1 1.6 20 abds6 / h tel 0.9 - - 7 h tel / w tel 3.3-3.9 3.5 ± 0.3 3.4 5 n spines uropodal diaeresis 11-13 12 ± 1.0 13 5 h ch1 / w ch1 2.0-2.5 2.2 ± 0.1 2.3 20 h ch1 / h ca1 1.2-1.5 1.3 ± 0.1 1.3 26 h ca1 / w ca1 2.1-2.9 2.6 ± 0.2 2.6 20 h ch2 / w ch2 2.4-3.1 2.7 ± 0.2 2.7 20 h ch2 / h ca2 0.7-1.0 0.8 ± 0.0 0.8 25 h ca2 / w ca2 4.8-7.3 6.1 ± 0.7 6.1 20 n spines p3 1-2 2 ± 0 2 5 n spines p5 13-22 19 ± 4 20 5

pereiopod 2.4-3.1 times as long as wide (n=20), 0.7-1.0 times length of carpus (n=25); tips of fingers rounded, without hooks, dactylus 1.3-1.6 times as long as palm (n=6); carpus 4.8-7.3 times as long as wide (n=20), 1.4-1.5 times as long as merus (n=5).

Third pereiopod ( Fig. 47 F-G) slender, dactylus 2.8-4.0 times as long as wide (terminal spine included, without spines of flexor margin; n=5), terminating in one large claw with 1-2 accessory spines on flexor margin; propodus 12.5-17.0 times as long as wide, 4.8-6.5 times as long as dactylus; carpus 5.5-6.5 times as long as wide, 0.5-0.6 times as long as propodus, 0.5 times as long as merus; merus 9.2-9.9 times as long as wide, bearing 2-3 strong, movable spines on posterior margin of outer surface.

Fifth pereiopod slender ( Fig. 47 I-J), dactylus 3.4-4.5 times as long as wide (terminal spine included, without spines of flexor margin; n=5), terminating in one large claw with 13- 22 accessory spines on flexor margin; propodus 16.0-22.0 times as long as wide, 4.4-5.8 times as long as dactylus; carpus 4.9-6.5 times as long as wide, 0.5-0.6 times as long as propodus, 0.6 times as long as merus; merus 9.1-10.0 times as long as wide, bearing 2-3 strong, movable spines on posterior margin of outer surface.

Endopod of male first pleopod ( Fig. 47K ) elongated triangular, 1.6-2.0 times as long as proximally wide (n=5), without appendix interna. Appendix interna of male second pleopod ( Fig. 47L ) 0.8-0.9 times length of appendix masculina (n=5).

Ovigerous females with 19- 29 eggs (n= 2 females); egg size 0.8-1.0 x 0.5-0.6 mm (n=48, eggs with eyes).

Distribution. – C. woltereckae is endemic to Lake Towuti, where it is widely distributed ( Fig. 46A ).

Biology and ecology. – C. woltereckae is a hard substrate dweller on smaller rocks mainly in shallow water, but also in deeper water regions (below 3 m) between larger rocks (boulders). When disturbed, in tries to escape side- or downwards rather than in other directions, but mainly stays attached to rocks. C. woltereckae is often found in syntopy with other rock dwellers in Lake Towuti, such as C. profundicola , C. spinata , C. striata , or C. glaubrechti .

Colour pattern. – Carapace with three transversal dark brown (sometimes reddish) bands ( Fig. 46 B-C), first two usually joint at dorsal surface to form a n-shaped band in lateral view. Appendages are either transparent or slightly pigmented. Most parts of first and second pereiopods usually bright white, abdomen with a conspicuous white stripe expanding laterally along each side, dorsally densely covered with dark brown bands except for a white belt on the posterior of the carapace. Uropods with white-pigmented tips or unpigmented. Eggs usually dark brown. This colour pattern remains visible even if the shrimp is under stress, the intensity of the colour merely fades. When feeding, the white chelipeds were observed to be always clearly visible, whereas the rest of the (darker coloured) body was more or less camouflaged.

Taxonomic remarks. – The colour morph of living specimens closely resembles C. spongicola . Therefore, both species can easily be confused in the field, although C. woltereckae is a typical rock dweller and has a much wider distribution (vs. sponge dweller and restricted to the outlet bay of Lake Towuti). It is generally also larger (carapace length 2.4-3.8, median 2.8 vs. in 1.8-2.8, median 2.4 in C. spongicola ) and has a longer rostrum (reaching beyond end of scaphocerite vs. reaching to or slightly beyond third segment of antennular peduncle in C. spongicola ). As alcohol bleached material, C. woltereckae is almost identical with C. striata and C. glaubrechti , although the colour pattern in living specimens always allows an unambiguous separation. It slightly differs from both by a lower number of spines on the dactylus of the fifth pereiopod (13-22, median 20 vs. 14-35, median 28 in C. glaubrechti and 24-35, median 33 in C. striata ). Also the dimorphic character of the rostrum in C. striata could not be observed in C. woltereckae .

In the molecular phylogeny ( Figs. 63-64 ), C. woltereckae forms a single clade with the other rock dwellers C. striata and C. glaubrechti , and the sponge dweller C. spongicola , but their relationship is not resolved within this clade (compare von Rintelen et al., 2007b; for further details see taxonomic remarks on C. striata ).

Figures

Fig. 46. Caridina woltereckae from the Malili lake system. A. Distribution. B.-C. Colour pattern of living animals (not to scale). Pictures courtesy of Chris Lukhaup.

Fig. 47. Caridina woltereckae from the Malili lake system. A. Cephalothorax and cephalic appendages, female (ZMB 29052); B. Scaphocerite, female (ZMB 29037); C. Preanal carina; D. Uropodal diaeresis, female (ZMB 29310); E. Telson, F. Third pereiopod, female (ZMB 29147); G. Dactylus of third pereiopod; H. Distal end of telson, female (ZMB 29310); I. Fifth pereiopod, female (ZMB 29147); J. Dactylus of fifth pereiopod; K. Endopod of male first pleopod (ZMB 29037); L. Appendix masculina of male second pleopod; M. SEM image of chela and carpus of first and second pereiopods, female (ZMB 29052); N. First pereiopod, female (ZMB 29052); O.; P. Second pereiopod. Scale bars: A-B = 1.0 mm; C, E-F, I, K-O = 0.5 mm; D, G-H, J = 0.1 mm.

Fig. 3. Standard morphometric characters in Caridina. A. Cephalothorax and abdomen (shrimp drawing modified from Woltereck, 1937a: 215). B. Rostrum and cephalic appendages. C. First and second pereiopod. D. Tailfan (telson and uropods). E. Third and fifth pereiopod. Abbreviations. antp (length of antennular peduncle), cl (carapace length), rl (rostrum length), abds5 (length of fifth abdominal somite), abds6 (length of sixth abdominal somite), h tel (length/height of telson), w tel (width of telson), h ch1 (length/height of chela of first pereiopod), w ch1 (width of chela of first pereiopod), h ca1 (length/height of carpus of first pereiopod), w ca1 (width of carpus of first pereiopod), h ch2 (length/height of chela of second pereiopod), w ch2 (width of chela of second pereiopod), h ca2 (length/height of carpus of second pereiopod), w ca2 (width of carpus of second pereiopod), n spines p3 (number of spines on the dactylus of the third pereiopod), n spines p5 (number of spines on the dactylus of the fifth pereiopod).

Fig. 63. Bayesian Inference phylogram (mtDNA, 16S and COI) of Caridina from the ancient lakes of Sulawesi (for other taxa compare von Rintelen et al., in review). Numbers on branches are, from top, Bayesian posterior probabilities, ML and MP bootstrap values. The scale bar indicates the number of substitutions per site. For each sequenced specimen museum accession numbers are provided. Locality abbreviations (compare Fig. 1): Lam (Lampesue River catchment), LT (Lake Lontoa), MHL (Lake Mahalona), MS (Lake Masapi), MT (Lake Matano), MTca (Lake Matano catchment), Pat (Patingko River), Pon (Ponsoa River), TW (Lake Towuti), TWca (Lake Towuti catchment), PS (Lake Poso), PSca (Lake Poso catchment), SSul (South Sulawesi), SESul (Southeast Sulawesi).

Fig. 64. Bayesian Inference phylogram (mtDNA, 16S and COI) showing taxa within the two Malili clades (for other taxa compare von Rintelen et al., 2009). For each sequenced specimen museum accession numbers are provided. Locality abbreviations (compare Fig. 1): Lam (Lampesue River catchment), LT (Lake Lontoa), MHL (Lake Mahalona), MS (Lake Masapi), MT (Lake Matano), MTca (Lake Matano catchment), Pat (Patingko River), Pon (Ponsoa River), TW (Lake Towuti), TWca (Lake Towuti catchment), SSul (South Sulawesi).