Caridina striata, Rintelen & Cai, 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 : 410-415

Caridina striata , new species

( Figs. 39–41 ; Table 15)

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

Material examined. – Holotype: ovigerous female, cl 3.5 mm ( MZB Cru 2121), Indonesia, Sulawesi Selatan, Lake Towuti , north shore, 02°38.56'S, 121°27.82'E, loc. 66-03, on rocks, coll. K. & T. von Rintelen, 26 Sep.2003.

Paratypes ( Lake Towuti ) – 7 ex. ( ZMB 29023, 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 ; 6 ex. ( ZMB 29048, n=6, some SEM material), south shore, approx. 2 km east of Cape Mea , 02°55.8'S, 121°26.92'E, loc. 74-03, on rocks, coll. K . & T. von Rintelen , 28 Sep.2003 ; 11 ex. ( MZB Cru 1815, n=5; ZMB 29095, n=6, some SEM material), 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 ; 2 ex. ( ZMB 29169, n=2, some SEM material), 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 ; 4 ex. ( ZMB 29170, n=4), north shore, west of Cape Manu , 02°41.67'S, 121°36.85'E, loc. 69-03, on boulders in deeper water, coll. K . & T. von Rintelen , 27 Sep.2003 ; 15 ex. ( MZB Cru 1816, n=7; ZMB 29171, n=8), 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 ; 40 ex. ( MZB Cru 1817, n=25; ZMB 29172, n=15), 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 1818, n=6; ZMB 29173, n=7), 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 ; 13 ex. ( MZB Cru 1819, n=6; ZMB 29174, n=7), 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 ; 16 ex. ( MZB Cru 1820, n=8; ZMB 29175, n=8), 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 ; 9 ex. ( MZB Cru 1821, n=4; ZMB 29176, n=5), east shore, 02°52.79'S, 121°31.18'E, loc. 72-03, on rocks, coll. K . & T. von Rintelen , 27 Sep.2003 ; 7 ex. ( ZMB 29177), west shore, at entrance to outlet bay, Cape Larona , 02°48.43'S, 121°24.75'E, loc. 73-03, on rocks, coll. K . & T. von Rintelen , 8 Oct.2003 ; 4 ex. ( ZMB 29178), 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 ; 9 ex. ( ZMB 29299, n=9 and few juveniles, some SEM material), west shore, 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 ; 1 ex. ( ZMB 29337), Loeha Island , southwest shore, 02°45.58'S, 121°31.14'E, loc. 149-04, on rocks in deeper water, coll. K . & T. von Rintelen , 5 Aug.2004 ; 5 ex. ( MZB Cru 1822), west shore, outlet bay, 02°46.277'S, 121°21.83'E, loc. 02-05, on sponge, coll. K . & T. von Rintelen , 3 Jan.2005 .

Paratypes ( Lake Mahalona ) – 44 ex. ( MZB Cru 1823, n=22; ZMB 29039, n=22 and some juveniles, some SEM material), northwest shore, at cape, 02°34.72'S, 121°29.12'E, loc. 56-03, on rocks, coll. K . & T. von Rintelen , 23 Sep.2003 ; 5 ex. ( ZMB 29102, n=5, some SEM material), east shore, 02°34.217'S, 121°30.681'E, loc. 147-04, on rocks, coll. K . & T. von Rintelen , 3 Aug.2004 ; 17 ex. ( MZB Cru 1824, n=8; ZMB 29298, n=9), north shore, at cape, 02°34.71'S, 121°29.144'E, loc. 148-04, on mixed substrate, coll. K . & T. von Rintelen , 3 Aug.2004 .

cl (mm) 1.7-3.8 3.0 ± 0.5 3.1 36 rl / cl 0.8-2.4 1.3 ± 0.4 1.1 36 n dorsal rostral teeth 3-25 12 ± 8 15 36 n ventral rostral teeth 4-28 9 ± 6 7 36 abds6 / cl 0.5-0.8 0.6 ± 0.1 0.6 36 abds6 / abds5 1.4-2.1 1.7 ± 0.2 1.7 20 abds6 / h tel 0.8-1.1 1.0 ± 0.1 1.0 14 h tel / w tel 2.9-3.7 3.4 ± 0.4 3.4 5 n spines uropodal diaeresis 11-14 13 ± 1 13 5 h ch1 / w ch1 2.2-3.0 2.4 ± 0.2 2.4 21 h ch1 / h ca1 1.1-1.3 1.2 ± 0.1 1.2 35 h ca1 / w ca1 2.5-3.5 2.9 ± 0.3 2.8 21 h ch2 / w ch2 2.7-4.0 3.1 ± 0.3 3.0 22 h ch2 / h ca2 0.7-1.0 0.7 ± 0.1 0.7 20 h ca2 / w ca2 5.5-7.5 6.3 ± 0.5 6.1 21 n spines p3 2-3 3 ± 0 3 5 n spines p5 24-35 31 ± 5 33 5

Description. – Carapace length 1.7-3.8 mm (n=36). Rostrum ( Fig. 40 A-C; Table 15) generally long to very long, anterior upturned, reaching beyond end of scaphocerite; rostrum dimorphic, either very long and slender, reaching far beyond end of scaphocerite ( Fig. 40B ) or shorter and broader with less teeth, reaching beyond end of scaphocerite ( Fig. 40A ); 0.8-2.4 times as long as carapace (n=36), armed dorsally with 3-25 teeth (including 3-5 teeth posterior to orbital margin), anterior less densely spaced, armed ventrally with 4-28 teeth. Antennal spine situated below inferior orbital angle. Pterygostomial angle broadly rounded. Eyes well developed, anterior end 0.6 times length of basal segment of antennular peduncle (n=5). Antennular peduncle 1.0-1.1 times as long as carapace (n=5), second segment 1.8-2.8 times length of third segment, third segment 0.2-0.4 times length of basal segment. Stylocerite reaching 0.9-1.1 times length of basal segment of antennular peduncle (n=5). Scaphocerite ( Fig. 40F ) 5.0-5.7 times as long as wide (n=5).

Sixth abdominal somite 0.5-0.8 times length of carapace (n=36), 1.4-2.1 times as long as fifth somite (n=20), 0.8-1.1 times length of telson (n=14). Telson ( Fig. 40 G-H, K-L) 2.9-3.7 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. 40E ) rounded, without a spine. Uropodal diaeresis ( Fig. 40D ) with 11-14 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. Epipod present on first pereiopod. Incisor process of mandible ( Fig. 41A ) ending in a row of 3-4 small teeth, molar process truncated. Lower lacinia of maxillula ( Fig. 41B ) broadly rounded, upper lacinia elongated, with numerous distinct teeth and setae on inner margin, palp slender. Upper endites of maxilla ( Fig. 41C ) subdivided, palp short, scaphognathite tapering posteriorly with numerous long, curved setae at posterior end. Distal end of palp of first maxilliped ( Fig. 41F ) triangular, with a finger-like projection; flagellum of the exopod very elongated, endopod high, reaching half the flagellum of exopod in length. Second maxilliped ( Fig. 41E ) typical. Third maxilliped ( Fig. 41D ) with ultimate segment distinctly shorter than penultimate segment.

Chela and carpus of first pereiopod distinctly stouter and broader than chela and carpus of second pereiopod ( Fig. 40 Q-S); chela of first pereiopod 2.2-3.0 times as long as wide (n=21), 1.1-1.3 times length of carpus (n=35); tips of fingers rounded, without hooks; dactylus 1.0-1.3 times as long as palm (n=7); carpus 2.5-3.5 times as long as wide (n=21), 1.2-1.4 times length of merus (n=5). Chela of second pereiopod 2.7-4.0 times as long as wide (n=22), 0.7-1.0 times length of carpus (n=20); tips of fingers rounded, without hooks, dactylus 1.1-1.4 times as long as palm (n=7); carpus 5.5-7.5 times as long as wide (n=21), 1.3-1.5 times as long as merus (n=5).

Third pereiopod ( Fig. 40I,M ) slender, dactylus 4.4-5.4 times as long as wide (terminal spine included, without spines of flexor margin; n=5), terminating in one large claw with 2-3 accessory spines on flexor margin; propodus 11.8-12.7 times as long as wide, 3.1-3.6 times as long as dactylus; carpus 5.2-6.6 times as long as wide, 0.6-0.7 times as long as propodus, 0.5 times as long as merus; merus 8.9-9.7 times as long as wide, bearing 3-4 strong, movable spines on posterior margin of outer surface.

Fifth pereiopod slender ( Fig. 40J,N ), dactylus 4.4-6.0 times as long as wide (terminal spine included, without spines of flexor margin; n=5), terminating in one large claw with 24- 35 accessory spines on flexor margin; propodus 13.1-17.6 times as long as wide, 3.1-4.2 times as long as dactylus; carpus 5.0-6.4 times as long as wide, 0.5 times as long as propodus, 0.5-0.6 times as long as merus; merus 9.1-9.7 times as long as wide, bearing 3-4 strong, movable spines on posterior margin of outer surface.

Endopod of male first pleopod ( Fig. 40O ) elongated triangular, 1.6-2.1 times as long as proximally wide (n=5), without appendix interna. Appendix interna of male second pleopod ( Fig. 40P ) 0.8-1.0 times length of appendix masculina (n=5).

Ovigerous females with 17- 38 eggs (n= 3 females); egg size 0.8-0.9 x 0.5 mm (n=37, eggs with and without eyes).

Distribution. – C. striata is endemic to the Malili lake system. There, widely distributed and often numerous in Lake Towuti, but was also found in Lake Mahalona ( Fig. 39B ).

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

Colour pattern. – Body red, laterally with characteristic white stripes, dorsally with some white spots ( Fig. 39A ). The uropods sometimes bear red and white patches on the distal margin. Appendages either transparent or reddishtransparent. First and second pereiopod usually conspicuously white. When animals are feeding, the white chelipeds were observed to be always clearly visible, whereas the rest of the (darker coloured) body was more or less camouflaged. This colour pattern remains visible even if the shrimp is under stress, the intensity of the colour merely fades.

Etymology. – The name Caridina striata , new species, refers to the characteristic colour pattern of red and white stripes (the Latin word striatus means striped).

Taxonomic remarks. – As alcohol bleached material, C. striata is almost identical with C. glaubrechti and C. woltereckae , although the colour pattern in living animals allows an unambiguous separation. It slightly differs from C. woltereckae by a higher number of spines on the dactylus of the fifth pereiopod (24-35, median 33 vs. 13-22, median 20 in C. woltereckae ). The dimorphic character of the rostrum in C. striata was not observed in the other two species.

In the molecular phylogeny ( Figs. 63-64 ), all three species form a single clade with the sponge dweller C. spongicola , but their relationship is not resolved within this clade (compare von Rintelen et al., 2007b, in review). However, the distinct colour patterns in all three species were found to be stable over the years of sampling. While morphological differences are largely lacking, they differ in behaviour and distribution (compare von Rintelen et al., 2007b, in review). C. striata was observed to be generally more active and faster than the other two rock dwellers and usually tried to escape sidewards instead of staying attached to a rock as observed in C. glaubrechti and C. woltereckae . C. striata also occurs in Lake Mahalona, whereas the others seem to be restricted to Lake Towuti.

Figures

Fig. 39. Caridina striata from the Malili lake system. A. Cephalothorax and cephalic appendages, female with short and stout rostrum (ZMB 29048); B. Cephalothorax and cephalic appendages, female with long and slender rostrum (ZMB 29169); C. Rostrum variability (ZMB 29023); D. Uropodal diaeresis, male (ZMB 29023); E. Preanal carina, F. Scaphocerite; G. Telson, female with short and stout rostrum (ZMB 29048); H. Telson, female with long and slender rostrum (ZMB 29169); I. Dactylus of third pereiopod, female (ZMB 29048); J. Dactylus of fifth pereiopod; K. Distal end of telson (ZMB 29048); L. Distal end of telson (ZMB 29169); M. Third pereiopod, female (ZMB 29048); N. Fifth pereiopod; O. Endopod of male first pleopod (ZMB 29023); P. Appendix masculina of male second pleopod; Q. First pereiopod, female (ZMB 29048); R. Second pereiopod; S. SEM image of chela and carpus of first and second pereiopods, female (ZMB 29095). Scale bars: A-C, F = 1.0 mm; E, G-H, M-S = 0.5 mm; D, I-L = 0.1 mm.

Fig. 40. Caridina striata from the Malili lake system. A. Colour pattern of living animals (not to scale). B. Distribution. Picture on the right courtesy of Chris Lukhaup.

Fig. 41. Caridina striata from the Malili lake system. A. Mandible (ZMB 29172); B. Maxillula; C. Maxilla; D. third maxilliped; E. second maxilliped; F. first maxilliped. Scale bars: A-F = 1mm.

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).