Caridina H. Milne Edwards, 1837

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 : 355-359

Caridina H. Milne Edwards, 1837

Caridina H. Milne Edwards, 1837: 362 .

Type species. – Caridina typus H. Milne Edwards, 1837: 363 (type locality unknown, gender feminine), by monotypy.

Paratypes (all Lake Matano ) – 24 ex. ( MZB Cru 1542, n=10; ZMB 29024, n=14, some SEM material), south shore, Soroako, Salonsa , INCO boat house, 02°30.71'S, 121°20.45'E, loc. 19-03, on gravel in shallow water, coll. K . & T. von Rintelen, 19 Sep.2003 ; 24 ex. ( MZB Cru 1541, n=14 and ZMB 29049, n=10, some SEM material), east shore, just at entrance to outlet bay, 02°31.54'S, 121°27.00'E, loc. 43-03, on gravel in shallow water, coll. K . & T. von Rintelen, 18 Sep.2003 ; 9 ex. ( MZB Cru 1548, n=4; ZMB 29050, n=5, some SEM material), north shore, 02°27.28'S, 121°21.21'E, loc. 98-03, on gravel, coll. K . & T. von Rintelen, 1 Oct.2003 ; 25 ex. ( MZB Cru 1544, n=13; ZMB 29051, n=12, some SEM material), northwest corner, 02°27.71'S, 121°13.03'E, loc. 102-03, on boulders in deeper water, coll. K . & T. von Rintelen, 1 Oct.2003 ; 9 ex. ( MZB Cru 1546, n=5; ZMB 29103, n=4, some SEM material), east shore, south bay, 02°32.77'S, 121°26.71'E, loc. 45-03, on gravel, coll. K . & T. von Rintelen, 1 Oct.2003 ; 10 ex. ( MZB Cru 1547, n=5; ZMB 29104, n=5 and few juveniles, some SEM material), southwest shore, Cape Nikomene, 02°32.24'S, 121°24.76'E, loc. 46-03, on gravel, coll. K . & T. von Rintelen, 1 Oct.2003 ; 3 ex. ( ZMB 29153, n=3 and few juveniles), south shore, near cave entrance, 02°29.85'S, 121°18.66'E, loc. 60-03, on boulders in deeper water, coll. K . & T. von Rintelen, 24 Sep.2003 ; 3 ex. ( ZMB 29155),south shore, 02°27.84'S, 121°13.88'E, loc. 63-03, on gravel, coll. K . & T. von Rintelen, 24 Sep.2003 ; 3 ex. ( ZMB 29156, some SEM material),north shore, 02°25.67'S, 121°16.54'E, loc. 65-03, on gravel, coll. K . & T. von Rintelen, 25 Sep.2003 ; 4 ex. ( ZMB 29157), north shore, 02°26.36'S, 121°19.03'E, loc. 84-03, on gravel, coll. K . & T. von Rintelen, 1 Oct.2003 ; 14 ex. ( MZB Cru 1545, n=7; ZMB 29326, n=7, some SEM material), south shore, 02°27.85'S, 121°13.87'E, loc. 125-04, on boulders in deeper water, coll. P. Koller & K. von Rintelen, 1 Aug.2004 ; 1 ex. ( ZMB 29327), south shore, canal between island and mainland, 02°28.46'S, 121°15.83'E, loc. 62-03, on gravel, coll. K . & T. von Rintelen, 1 Oct.2003 ; 3 ex. ( ZMB 29328), north shore, 02°26.274'S, 121°18.83'E, loc. 133-04, on gravel, coll. K . & T. von Rintelen, 22 Jul.2004 ; 1 ex. ( ZMB 29329), west shore, 02°26.828'S, 121°12.988'E, loc. 135-04, on gravel, coll. K . & T. von Rintelen, 23 Jul.2004 ; 3 ex. ( ZMB 29330), north shore, 02°27.311'S, 121°21.047'E, loc. 09-05, on gravel in shallow water, coll. K . & T. von Rintelen, 7 Jan.2005 ; 4 ex. ( MZB Cru 1543), Lake Matano (no details given), loc. F2-02, substrate unknown, coll. F. Herder & A. Nolte, 1 Dec.2002 .

Description. – Carapace length 1.5-3.4 mm (n=53). Rostrum ( Fig. 5A ; Table 3) reaching near or to end of scaphocerite, slightly sickle-shaped, 0.9-1.3 times as long as carapace (n=39), armed dorsally with 15-25 teeth (including 3-7 teeth posterior to orbital margin), anterior less densely spaced, armed ventrally with 5-11 teeth. Antennal spine situated below inferior orbital angle. Pterygostomial angle broadly rounded. Eyes well developed, anterior end 0.5 times length of basal segment of antennular peduncle (n=5). Antennular peduncle 1.0-1.3 times as long as carapace (n=5), second segment 2.0-2.2 times length of third segment, third segment 0.3-0.4 times length of basal segment. Stylocerite reaching 0.8-0.9 times length of basal segment of antennular peduncle (n=5). Scaphocerite ( Fig. 5D ) 4.3-5.7 times as long as wide (n=5).

Sixth abdominal somite 0.5-0.7 times length of carapace (n=35), 1.4-2.0 times as long as fifth somite (n=32), 0.8-1.0 times length of telson (n=24). Telson ( Fig. 5C,H ) 3.1-3.3 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 3-4 pairs of spines, lateral pair distinctly longer than intermediate pairs, median pair shortest. Preanal carina ( Fig. 5E ) with a spine. Uropodal diaeresis ( Fig. 5B ) with 12-13 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. Epipod present on first pereiopod, but reduced. Incisor process of mandible ( Fig. 6A ) ending in a row of 3-4 small teeth, molar process truncated. Lower lacinia of maxillula ( Fig. 6B ) broadly rounded, upper lacinia elongate, with numerous distinct teeth and setae on inner margin, palp slender. Upper endites of maxilla ( Fig. 6C ) subdivided, palp elongated, scaphognathite tapering posteriorly with numerous long, curved setae at posterior end. Distal end of palp of first maxilliped ( Fig. 6F ) triangular, with a long finger-like projection; flagellum of the exopod very elongated, endopod high, reaching to half the flagellum of exopod in length. Second maxilliped ( Fig. 6D ) typical. Third maxilliped ( Fig. 6E ) with ultimate segment slightly shorter than penultimate segment.

First and second pereiopod very slender, chela and carpus of first pereiopod distinctly stouter and broader than chela and carpus of second pereiopod ( Fig. 5 M-P); chela of first pereiopod 2.4-3.8 times as long as wide (n=35), 0.9-1.1 times length of carpus (n=39); tips of fingers rounded, without hooks; dactylus 1.7-2.4 times as long as palm (n=6); carpus 3.3-4.6 times as long as wide (n=35), 1.4-1.8 times length of merus (n=5). Chela of second pereiopod 2.8-3.7 times as long as wide (n=35), 0.6-0.7 times length of carpus (n=39); tips of fingers rounded, without hooks, dactylus 1.6-2.1 times cl (mm) 2.3-3.8 2.8 ± 0.4 2.7 29 rl / cl 0.6-1.2 0.9 ± 0.1 0.9 32 n dorsal rostral teeth 14-28 20 ± 3 20 32 n ventral rostral teeth 3-7 5 ± 1 5 32 abds6 / cl 0.5-0.7 0.6 ± 0.1 0.6 15 abds6 / abds5 1.4-1.8 1.6 ± 0.1 1.6 15 abds6 / h tel 0.9-1.0 0.9 ± 0.0 0.9 10 h tel / w tel 2.9-3.5 3.3 ± 0.2 3.4 6 n spines uropodal diaeresis 12-13 13 ± 1 13 5 h ch1 / w ch1 1.8-2.3 2.1 ± 0.2 2.1 18 h ch1 / h ca1 1.1-1.4 1.2 ± 0.1 1.2 17 h ca1 / w ca1 2.0-3.1 2.7 ± 0.3 2.7 13 h ch2 / w ch2 2.3-3.5 2.8 ± 0.3 2.8 18 h ch2 / h ca2 0.7-0.9 0.8 ± 0.1 0.7 22 h ca2 / w ca2 4.3-7.0 5.7 ± 0.9 5.7 18 n spines p3 3-6 4 ± 1 4 5 n spines p5 27-39 34 ± 5 33 5

as long as palm (n=6); carpus 6.9-8.5 times as long as wide (n=35), 1.4-1.9 times as long as merus (n=5).

Third pereiopod ( Fig. 5F,I ) slender, dactylus 3.8-5.3 times as long as wide (terminal spine included, without spines of flexor margin; n=5), terminating in one large claw with 2 accessory spines on flexor margin; propodus 14.7-24.2 times as long as wide, 4.9-6.2 times as long as dactylus; carpus 7.5-9.2 times as long as wide, 0.6-0.7 times as long as propodus, 0.5-0.6 times as long as merus; merus 11.0-12.4 times as long as wide, bearing 3-4 strong, movable spines on posterior margin of outer surface.

Fifth pereiopod slender ( Fig. 5G,J ), dactylus 3.0-5.1 times as long as wide (terminal spine included, without spines of flexor margin; n=5), terminating in one large claw with 25- 30 accessory spines on flexor margin; propodus 17.3-24.2 times as long as wide, 4.4-7.0 times as long as dactylus; carpus 6.6-9.0 times as long as wide, 0.5 times as long as propodus, 0.6 times as long as merus; merus 9.4-13.8 times as long as wide, bearing 1-3 strong, movable spines on posterior margin of outer surface.

Endopod of male first pleopod ( Fig. 5K ) elongated triangular, 1.7-2.3 times as long as proximally wide (n=5), without appendix interna. Appendix interna of male second pleopod ( Fig. 5L ) 0.8-0,9 times length of appendix masculina (n=5).

Ovigerous females with 8- 14 eggs (n= 7 females); egg size 1.0-1.2 x 0.5-0.7 mm (n=88, eggs with and without eyes).

Distribution. – C. dennerli is endemic to Lake Matano and widely distributed within the lake ( Fig. 4A ).

Biology and ecology. – C. dennerli is a hard substrate dweller (rocks) occurring in different water depths (from shallow water to approx. – 10 m), on or under small rocks, and between boulders. When disturbed, it tries to escape side- or downwards rather than in other directions, but frequently stays attached to a rock when it is uplifted.

Colour pattern. – C. dennerli has one of the most conspicuous colour patterns among the ancient lake species ( Fig. 4 B-C). Body and most appendages are primarily dark red to purple; body covered with several white conspicuous spots and one distinct white dot on the dorsodistal part of the abdomen. Chela and carpus of the first and second pereiopod bright white and distinctly contrasting the otherwise red colour. Antenna, antenulla, and scaphocerite also white. When feeding, the white chelipeds were observed to be always clearly visible, whereas the rest of the (dark coloured) body was more or less camouflaged; eggs are also dark red. Under stress, red body colour can change to blue, but only temporarily. This change of colour was only observed in a small water tank minutes after being caught.

Etymology. – Caridina dennerli , new species, is dedicated to the German company Dennerle GmbH, which kindly supported the authors’ shrimp project on the ancient lake species of Sulawesi.

Taxonomic remarks. – The slightly falciform rostrum is a more constant character in C. dennerli than in other species. Thus, it is already distinguishable in most cases at first sight. With regard to the rostrum, C. dennerli mainly resembles C. holthuisi , but also other species from Lake Towuti, e.g. the broad rostrum morph of C. striata , although it is more slender than in C. holthuisi and usually broader and shorter than in C. striata (reaching near or to end of scaphocerite vs. longer than in C. striata ). It differs from C. holthuisi not only in its substrate preference (rocks vs. leaf litter in C. holthuisi ) and colour pattern (compare respective description), but also by a different number of ventral teeth on the rostrum (5-11, median 9 vs. 3-7, median 5 in C. holthuisi ) and distinctly more slender pereiopods in C. dennerli (for example chela of first pereiopod 2.4-3.8, median 2.7 vs. 1.8-2.3, median 2.1 in C. holthuisi ).

In the molecular phylogeny ( Figs. 63-64 ), C. dennerli is genetically distinct form the other species mentioned above.

Figures

Fig. 5. Caridina dennerli from the Malili lake system. A. Cephalothorax and cephalic appendages, female (ZMB 29049); B. Uropodal diaeresis, male (ZMB 29051); C. Telson, male (ZMB 29156); D. Scaphocerite, male (ZMB 29051); E. Preanal carina, F. Third pereiopod, female (ZMB 29326); G. Fifth pereiopod; H. Distal end of telson male (ZMB 29156); I. Dactylus of third pereiopod female (ZMB 29326); J. Dactylus of fifth pereiopod; K. Endopod of male first pleopod (ZMB 29051); L. Appendix masculina of male second pleopod; M. First pereiopod, male (ZMB 29156); N. Second pereiopod; O. SEM image of anterior part of chela, male (ZMB 29104); P. SEM image of chela and carpus of first and second pereiopods, female (ZMB 29024). Scale bars: A, D = 1.0 mm; C, E-G, K-P = 0.5 mm; B, H-J = 0.1 mm.

Fig. 6. Caridina dennerli from the Malili lake system. A. Mandible (ZMB 29024); B. Maxillula; C. Maxilla; D. second maxilliped; E. third maxilliped; F. first maxilliped. Scale bars: A-F = 1mm.

Fig. 4. Caridina dennerli from the Malili lake system. A. Distribution. B.-C. Colour pattern of living animals (not to scale). Pictures courtesy of Chris Lukhaup.

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).