Caridina parvula, 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 : 392-396

Caridina parvula , new species

( Figs. 27–29 ; Table 11)

Material examined. – Holotype: ovigerous female (cl 3.2 mm) (MZB Cru 2127), Lake Towuti, southwest shore, Cape Sioloya, 02°50.7'S, 121 °26.32'E, loc. 77-03, on rocks, coll. K. & T. von Rintelen, 28 Sep.2003.

Paratypes (Lake Matano) – 2 ex. (ZMB 29221), north shore, 02°27.418'S, 121°21.533'E, loc. 10-05, on mixed substrate, coll. K. & T. von Rintelen, 7 Jan.2005; 1 ex. (ZMB 29229), east shore, just south of entrance to outlet bay, 02°31.54'S, 121°27.0'E, loc. 43-03, on rocks in shallow water, coll. K. & T. von Rintelen, 18 cl (mm) 2.1-3.0 2.6 ± 0.3 2.6 15 rl / cl 0.4-0.8 0.5 ± 0.1 0.5 15 n dorsal rostral teeth 11-18 15 ± 2 14 15 n ventral rostral teeth 2-6 4 ± 1 4 15 abds6 / cl 0.5-0.6 0.6 ± 0.0 0.6 14 abds6 / abds5 1.4-1.9 1.6 ± 0.2 1.6 7 abds6 / h tel 0.9-1.0 0.9 ± 0.0 0.9 13 h tel / w tel 2.8-3.4 3.1 ± 0.2 3.1 5 n spines uropodal diaeresis 12-18 16 ± 2 16 5 h ch1 / w ch1 2.2-2.5 2.4 ± 0.1 2.4 10 h ch1 / h ca1 0.9-1.6 1.1 ± 0.2 1.0 14 h ca1 / w ca1 3.3-4.1 3.8 ± 0.2 3.8 10 h ch2 / w ch2 2.5-3.4 3.1 ± 0.2 3.1 10 h ch2 / h ca2 0.5-1.2 0.7 ± 0.2 0.6 14 h ca2 / w ca2 4.3-9.8 7.8 ± 1.6 8.0 10 n spines p3 2-3 3 ± 1 3 4 n spines p5 34-39 37 ± 2 37 4

Sep. 2003; 1 ex. (ZMB 29242), north shore, 02°25.67'S, 121°16.54'E, loc. 65-03, on mixed substrate, coll. K. & T. von Rintelen, 25 Sep.2003 ; 17 ex. (MZB Cru 1801, n=8; ZMB 29243, n=9, some SEM material), west shore, north of Lake Matano, 02°26.91'S, 121°13.01'E, loc. 83-03, on rocks, coll. K. & T. von Rintelen, 1 Oct.2003 ; 2 ex. (ZMB 29247), south shore, east of Soroako , just west of Cape Patipuoho, 02°31.57'S, 121°23.41'E, loc. 99-03, on rocks, coll. K. & T. von Rintelen, 5 Oct.2003 ; 2 ex. (MZB Cru 1802), north shore, 02°26.274'S, 121°18.83'E, loc. 133-04, on rocks, coll. K. & T. von Rintelen, 22 Jul.2004 ; 2 ex. (MZB Cru 1803), south shore, 02°27.85'S, 121°13.87'E, loc. 125-04, on rocks, coll. P. Koller & K. von Rintelen, 1 Aug.2004 ; 2 ex. (MZB Cru 1805), south shore, Soroako, INCO boat house, 02°30.71'S, 121°20.45'E, loc. 19-03, on rocks, coll. K. & T. von Rintelen, 19 Sep.2003 ; 3 ex. (MZB Cru 1806), south shore, canal between island and mainland, 02°28.46'S, 121°15.83'E, loc. 62-03, on rocks, coll. K. & T. von Rintelen, 24 Jul.2004 ; 1 ex. (MZB Cru 1807), north shore, 02°26.36'S, 121°19.03'E, loc. 84-03, on rocks, coll. K. & T. von Rintelen, 1 Oct.2003 ; 1 ex. (ZMB 29437), Petea River , 02°32.672'S, 121°30.137'E, loc. F4-04, substrate unknown, coll. F. Herder, 25 Mar.2004 ; 1 ex. (MZB Cru 1813), Petea River, 02°32.64'S, 121°29.51'E, loc. 101-03, on rocks, coll. K. & T. von Rintelen, 6 Oct.2003 .

Paratypes ( Lake Mahalona ) – 3 ex. ( MZB Cru 1814), Tominanga River, approx. 1.5 km east of Lake Mahalona, 02°38.73'S, 121°31.95'E, loc. 59-03, on rocks, coll. K. & T. von Rintelen, 23 Sep.2003 .

Paratypes ( Lake Towuti ) – 1 ex. ( ZMB 29020), 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 ; 7 ex. ( ZMB 29064), southwest shore, Cape Sioloya , 02°50.7'S, 121°26.32'E, loc. 77-03, on rocks, coll. K . & T. von Rintelen , 28 Sep.2003 ; 5 ex. ( ZMB 29097), northwest shore, 02°40.647'S, 121°24.915'E, loc. 142-04, on mixed substrate, coll. K . & T. von Rintelen , 25 Jul.2004 ; 1 ex. ( ZMB 29098), west shore, south of Cape Timbalo , 02°42.91'S, 121°26.78'E, loc. 94-03, on rocks in shallow water, coll. K . & T. von Rintelen , 4 Oct.2003 ; 2 ex. ( ZMB 29108, some SEM material), 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 ; 10 ex. ( MZB Cru 1808, n=5; ZMB 29116, n=5), west shore, at entrance to outlet bay, Cape Larona, 02°48.43'S, 121°24.75'E, loc. 73-03, on leaf litter, coll. K . & T. von Rintelen , 27 Sep.2003 ; 3 ex. ( ZMB 29119, 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 ; 1 ex. ( ZMB 29226), east shore, 02°52.79'S, 121°31.18'E, loc. 72-03, on rocks, coll. K . & T. von Rintelen , 27 Sep.2003 ; 6 ex. ( ZMB 29263, some SEM material), west shore, west of Cape Timbalo , 02°42.631'S, 121°26.389'E, loc. 145-04, on mixed substrate, coll. K . & T. von Rintelen , 26 Jul.2004 ; 1 ex. ( MZB Cru 1809), northeast shore, at Lengkona, 02°40.483'S, 121°41.382'E, loc. 116-04, on mixed substrate, coll. K . & T. von Rintelen , 28 Jul.2004 ; 1 ex. ( MZB Cru 1810, ovigerous female with freshly hatched juveniles), west shore, north of Cape Sioloya, 02°50.389'S, 121°26.026'E, loc. 03-05, on rocks, coll. Y. Cai, K . & T. von Rintelen , 3 Jan.2005 ; 4 ex. ( MZB Cru 1811), west shore, Cape Bakara, 02°40.771'S, 121°26.11'E, loc. 144-04, on mixed substrate, coll. K . & T. von Rintelen , 26 Jul.2004 ; 4 ex. ( MZB Cru 1812), 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 ; Towuti catchment, Lemolemo River , 3 ex. ( ZMB 29028, some SEM material), 02°42.62'S, 121°40.99'E, loc. 85-03, on rocks, coll. K . & T. von Rintelen , 2 Oct.2003 .

Description. – Carapace length 2.1-3.0 mm (n=15). Rostrum ( Fig. 28A ; Table 11) short, not reaching to end of second segment of antennular peduncle, 0.4-0.8 times as long as carapace (n=15), armed dorsally with 11-18 teeth (including 2-7 teeth posterior to orbital margin), anterior less densely spaced, armed ventrally with 2-6 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 0.7-0.9 times as long as carapace (n=5), second segment 1.5-1.7 times length of third segment, third segment 0.3-0.4 times length of basal segment. Stylocerite reaching 0.9-1.0 times length of basal segment of antennular peduncle (n=5). Scaphocerite ( Fig. 28E ) 3.3-5.4 times as long as wide (n=5).

Sixth abdominal somite 0.5-0.6 times length of carapace (n=14), 1.4-1.9 times as long as fifth somite (n=7), 0.9-1.0 times length of telson (n=13). Telson ( Fig. 28D,I ) 2.8-3.4 times as long as wide (n=5), distal margin rounded, without projection, with 3-5 pairs of spinules and 1 pair of dorsolateral spinules; distal end with 3-5 pairs of spines, lateral pair longer than intermediate pairs, median pair usually shortest. Preanal carina ( Fig. 28B ) rounded, without a spine. Uropodal diaeresis ( Fig. 28C ) with 12-18 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 two pereiopods. Incisor process of mandible ( Fig. 29A ) ending in a row of 3-5 small teeth, molar process truncated. Lower lacinia of maxillula ( Fig. 29B ) broadly rounded, upper lacinia elongate, with numerous distinct teeth and setae on inner margin, palp slender. Upper endites of maxilla ( Fig. 29C ) subdivided, palp short, scaphognathite tapering posteriorly with numerous long, curved setae at posterior end. Distal end of palp of first maxilliped ( Fig. 29F ) triangular, not ending with a distinct finger-like projection; flagellum of the exopod stout, endopod high, not exceeding the flagellum of exopod in length. Second maxilliped ( Fig. 29E ) typical. Third maxilliped ( Fig. 29D ) with ultimate segment as long as 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. 28 K-L,O); chela of first pereiopod 2.2-2.5 times as long as wide (n=10), 0.9-1.6 times length of carpus (n=14); tips of fingers rounded, without hooks; dactylus 1.4-2.0 times as long as palm (n=5); carpus 3.3-4.1 times as long as wide (n=10), 1.2-1.3 times length of merus (n=5). Chela of second pereiopod 2.5-3.4 times as long as wide (n=10), 0.5-1.2 times length of carpus (n=14); tips of fingers rounded, without hooks, dactylus 1.5-1.8 times as long as palm (n=5); carpus 4.3-9.8 times as long as wide (n=10), 1.3-1.4 times as long as merus (n=5).

Third pereiopod ( Fig. 28 F-G) slender, dactylus 3.2-5.0 times as long as wide (terminal spine included, without spines of flexor margin; n=4), terminating in one large claw with 2-3 accessory spines on flexor margin; propodus 8.8-14.3 times as long as wide, 2.8-4.6 times as long as dactylus; carpus 4.8-7.4 times as long as wide, 0.6-0.7 times as long as propodus, 0.5-0.6 times as long as merus; merus 7.2-10.6 times as long as wide, bearing 3-4 strong, movable spines on posterior margin of outer surface.

Fifth pereiopod slender ( Fig. 28H,J ), dactylus 4.0-5.0 times as long as wide (terminal spine included, without spines of flexor margin; n=4), terminating in one large claw with 34- 39 accessory spines on flexor margin; propodus 11.3-16.7 times as long as wide, 3.0-4.0 times as long as dactylus; carpus 3.4-6.6 times as long as wide, 0.5-0.6 times as long as propodus, 0.5-0.7 times as long as merus; merus 7.3-10.6 times as long as wide, bearing 1-2 strong, movable spines on posterior margin of outer surface.

Endopod of male first pleopod ( Fig. 28M ) elongated triangular, 1.8-2.4 times as long as proximally wide (n=5), without appendix interna. Appendix interna of male second pleopod ( Fig. 28N ) 0.8-0.9 times length of appendix masculina (n=5).

Ovigerous females with 12- 15 eggs (n= 3 females); egg size 0.8-0.9 x 0.5-0.6 mm (n=37, eggs with and without eyes).

Distribution. – Endemic to the Malili lake system. There, widely distributed in Lake Matano and Lake Towuti, some specimens were found in Petea and Tominanga rivers, but none in Lake Mahalona ( Fig. 27 ).

Biology and ecology. – This small and rather inconspicuous species often lives in sympatry with other rock dwellers, for example C. loehae , under small rocks as its primary substrate in shallow water regions.

Colour pattern. – The colour pattern of C. parvula is rather inconspicuous compared to other species from the Malili lakes. The body usually shows a light red colouration, which can turn completely blue when under stress, with a few faint white transversal stripes. Body appendages are transparent. Eggs are the same colour as the body.

Etymology. – Caridina parvula refers to the small size of this new species (the Latin word parvus means little).

Taxonomic remarks. – C. parvula (carapace length 2.1-3.0 mm, median 2.6 mm) is one of the smallest species in the Malili lakes, similarly to C. loehae and C. spongicola , but differs from C. spongicola by a shorter rostrum (not reaching to end of second segment of antennular peduncle vs. longer in C. spongicola ), by a higher number of spines on the uropodal diaeresis (12-18, median 16 vs. 10-12, median 11 in C. spongicola ), and by a lower number of spines on the dactylus of the fifth pereiopod (34-39, median 37 vs. 21-31, median 27 in C. spongicola ). The very short and broad rostrum is characteristic for C. parvula . The length of the rostrum only resembles C. loehae , but is distinctly broader. Both species further differ by a different number of spines on the uropodal diaeresis (vs. 9-14, median 11 in C. loehae ) and on the dactylus of the fifth pereiopod (vs. 12-16, median 16 in C. loehae ). However, both species often occur in syntopy (on rocks in shallow water) and have a similar colour pattern, although the white markings in C. loehae are often more pronounced than in C. parvula .

In the molecular phylogeny( Figs. 63-64 ), C. parvula is genetically distinct from all other ancient lake species.

Figures

Fig. 27. Distribution of Caridina parvula in the Malili lake system.

Fig. 28. Caridina parvula from the Malili lake system. A. Cephalothorax and cephalic appendages, female (ZMB 29263); B. Preanal carina; C. Uropodal diaeresis, female (ZMB 29028); D. Telson; E. Scaphocerite, F. Dactylus of third pereiopod; G. Third pereiopod; H. Dactylus of fifth pereiopod; I. Distal end of telson; J. Fifth pereiopod; K. First pereiopod, female (ZMB 29243); L. second pereiopod; M. Endopod of male first pleopod (ZMB 29243); N. Appendix masculina of male second pleopod; O. SEM image of chela and carpus of first and second pereiopods, female (ZMB 29119). Scale bars: A, E = 1.0 mm; B, D, G, J-O = 0.5 mm; C, F, H-I = 0.1 mm.

Fig. 29. Caridina parvula from the Malili lake system. A. Mandible (ZMB 29064); 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).