Caridina glaubrechti, 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 : 359-364

Caridina glaubrechti , new species

( Figs. 7-9 ; Table 4)

Caridina sp.1 – von Rintelen et al., 2007b: 262, fig. 2b.

Material examined. – Holotype: female (cl 2.7 mm)( MZB Cru 2122), Lake Towuti , west shore, south of Cape Timbalo, 02°42.91'S, 121°26.78'E, loc. 94-03, coll. K. & T. von Rintelen, 4 Oct.2003.

Paratypes (all Lake Towuti ) – 5 ex. ( ZMB 29053, some SEM material), south shore, approx. 2 km east of Cape Mea, 02°55.8'S, 121°26.92'E, loc. 74-03, coll. K . & T. von Rintelen , 28 Sep.2003 ; 2 ex. ( ZMB 29074, some SEM material), north shore, bay east of Cape Bintu , 02°39.48'S, 121°33.25'E, loc. 68-03, coll. K . & T. von Rintelen , 26 Sep.2003 ; 26 ex. ( MZB Cru 1825, n=11; ZMB 29077, n=15), west shore, south of Cape Timbalo, 02°42.91'S, 121°26.78'E, loc. 94-03, coll. K . & T. von Rintelen , 4 Oct.2003 ; 1 ex. ( ZMB 29086, some SEM material), Larona River , 02°45.06'S, 121°20.12’E, loc. 50-03, coll. K . & T. von Rintelen , 21 Sep.2003 ; 12 ex. ( MZB Cru 1826, n=6; ZMB 29109, n=6), west shore, north of Cape Wasupute, 02°46.9'S, 121°27.94'E, loc. 78-03, coll. K . & T. von Rintelen , 26 Jul.2004 ; 7 ex. ( ZMB 29301), west shore, west of Cape Timbalo , 02°42.631'S, 121°26.389'E, loc. 145-04, coll. K . & T. von Rintelen , 26 Jul.2004 ; 3 ex. ( ZMB 29335), northwest shore, 02°40.897'S, 121°25.015'E, loc. 143-04, coll. K . & T. von Rintelen , 25 Jul.2004 ; 2 ex. ( MZB Cru 1827), 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 .

Description. – Carapace length 2.3-3.4 mm (n=11). Rostrum ( Fig. 8A ; Table 4) long, reaching beyond end of scaphocerite, 0.9-1.7 times as long as carapace (n=12), armed dorsally with 11-17 teeth (including 2-5 teeth posterior to orbital margin), anterior less densely spaced, armed ventrally with 5-16 teeth (n=9). Antennal spine situated below inferior orbital angle. Pterygostomial angle broadly rounded. Eyes well developed, anterior end 0.6-0.8 times length of basal segment of antennular peduncle (n=5). Antennular peduncle 1.0 times as long as carapace (n=5), second segment 1.8-2.1 times length of third segment, third segment 0.3 times length of basal segment. Stylocerite reaching 0.9 times length of basal segment of antennular peduncle (n=5). Scaphocerite ( Fig. 8D ) 4.0-5.7 times as long as wide (n=5).

Sixth abdominal somite 0.5-0.8 times length of carapace (n=10), 1.6-2.0 times as long as fifth somite (n=5), 0.8-1.2 times length of telson (n=11). Telson ( Fig. 8 F-G,M-N) 3.2-3.4 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 spines, median pair or median spine shortest. Preanal carina ( Fig. 8B ) rounded, without a spine. Uropodal diaeresis ( Fig. 8C ) 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 cl (mm) 2.3-3.4 2.9 ± 0.3 2.9 11 rl / cl 0.9-1.7 1.2 ± 0.3 1.1 12 n dorsal rostral teeth 11-17 15 ± 2 15 9 n ventral rostral teeth 5-16 9 ± 4 8 9 abds6 / cl 0.5-0.8 0.7 ± 0.1 0.7 10 abds6 / abds5 1.6-2.0 1.8 ± 0.2 1.8 5 abds6 / h tel 0.8-1.2 1.0 ± 0.1 1.0 11 h tel / w tel 3.2-3.4 3.3 ± 0.1 3.3 5 n spines uropodal diaeresis 11-14 13 ± 1 12 5 h ch1 / w ch1 2.0-2.4 2.2 ± 0.2 2.2 8 h ch1 / h ca1 1.1-1.4 1.2 ± 0.1 1.2 12 h ca1 / w ca1 1.9-3.4 2.6 ± 0.5 2.6 8 h ch2 / w ch2 2.3-3.2 2.8 ± 0.3 2.9 8 h ch2 / h ca2 0.7-0.8 0.8 ± 0.0 0.8 11 h ca2 / w ca2 4.8-6.7 5.7 ± 0.7 5.7 8 n spines p3 2-5 4 ± 1 4 4 n spines p5 14-35 26 ± 9 28 4

of podobranchs on second maxilliped reduced strongly to a laminate form. Epipod reduced or totally absent from the first pereiopod. Incisor process of mandible ( Fig. 9A ) ending in a row of 4-5 small teeth, molar process truncated. Lower lacinia of maxillula ( Fig. 9B ) broadly rounded, upper lacinia elongate, with numerous distinct teeth and setae on inner margin, palp slender. Upper endites of maxilla ( Fig. 9C ) subdivided, palp short, scaphognathite tapering posteriorly with numerous long, curved setae at posterior end. Distal end of palp of first maxilliped ( Fig. 9F ) triangular, not ending with a finger-like projection; flagellum of the exopod very elongated, endopod high, not exceeding the flagellum of exopod in length. Second maxilliped ( Fig. 9D ) typical. Third maxilliped ( Fig. 9E ) with ultimate segment as long as penultimate segment.

Chela and carpus of first pereiopod distinctly stouter and broader than chela and carpus of second pereiopod ( Fig. 8 O-Q); chela of first pereiopod 2.0-2.4 times as long as wide (n=8), 1.1-1.4 times length of carpus (n=12); tips of fingers rounded, without hooks; dactylus 1.1-1.3 times as long as palm (n=5); carpus 1.9-3.4 times as long as wide (n=8), 1.1-1.4 times length of merus (n=5). Chela of second pereiopod 2.3-3.2 times as long as wide (n=8), 0.7-0.8 times length of carpus (n=11); tips of fingers rounded, without hooks, dactylus 1.2-1.5 times as long as palm (n=5); carpus 4.8-6.7 times as long as wide (n=8), 1.4 times as long as merus (n=5).

Third pereiopod ( Fig. 8H,E ) slender, dactylus 3.6-4.2 times as long as wide (terminal spine included, without spines of flexor margin; n=4), terminating in one large claw with 2-5 accessory spines on flexor margin; propodus 11.4-15.0 times as long as wide, 4.2-5.5 times as long as dactylus; carpus 5.8-7.5 times as long as wide, 0.6-0.7 times as long as propodus, 0.5 times as long as merus; merus 9.0-11.3 times as long as wide, bearing 2-3 strong, movable spines on posterior margin of outer surface.

Fifth pereiopod slender ( Fig. 8 I-J), dactylus 3.8-4.5 times as long as wide (terminal spine included, without spines of flexor margin; n=4), terminating in one large claw with 14- 35 accessory spines on flexor margin; propodus 14.0-21.8 times as long as wide, 4.1-6.5 times as long as dactylus; carpus 5.0-7.2 times as long as wide, 0.5-0.6 times as long as propodus, 0.6-0.7 times as long as merus; merus 8.5-12.0 times as long as wide, bearing 2-3 strong, movable spines on posterior margin of outer surface.

Endopod of male first pleopod ( Fig. 8K ) elongated triangular, 1.8-2.7 times as long as proximally wide (n=5), without appendix interna. Appendix interna of male second pleopod ( Fig. 39L ) 0.8-0.9 times length of appendix masculina (n=5).

Ovigerous females with 20 eggs (n= 2 females); egg size 0.8-1.0 x 0.5-0.6 mm (n=40, eggs with and without eyes).

Distribution. – C. glaubrechti is endemic to Lake Towuti and was mainly found in the western part of the lake ( Fig. 7A ).

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

Colour pattern. – The primary colour of C. glaubrechti is brown with several white bands or patches all over the body (including pereiopods and uropods; Fig. 7B ). A conspicuous white band is visible at the distal part of the abdomen. Appendages are transparent or partly brownish. Eggs are brown. This colour pattern remains visible even if the shrimp is under stress; the intensity of the colour merely fades.

Etymology. – Caridina glaubrechti , new species, is dedicated to Matthias Glaubrecht, who initiated the current research on endemic species flocks from the ancient lakes of Sulawesi, and who also collected several shrimp specimens.

Taxonomic remarks. – The colour pattern of C. glaubrechti closely resembles the colour pattern of C. tenuirostris , but both species not only differ in their substrate preference (rocks vs. wood in C. tenuirostris ), but by the continuous dorsal denticulation of the rostrum (vs. anterior dorsal part always completely unarmed in C. tenuirostris ), a different number of spines on the uropodal diaeresis (11-14, median 12 vs. 7-8, median 8 in C. tenuirostris ), and on the dactylus of the fifth pereiopod (14-35, median 28 vs. 11-15, median 14 in C. tenuirostris ).

As alcohol bleached material, C. glaubrechti is almost identical with C. striata and C. woltereckae , although the colour pattern in living specimens always allows an unambiguous separation. It slightly differs from C. woltereckae by a higher number of spines on the dactylus of the fifth pereiopod (14-35, median 28 vs. 13-22, median 20 in C. woltereckae ). Also, the dimorphic character of the rostrum in C. striata could not be observed in C. glaubrechti .

In the molecular phylogeny ( Figs. 63-64 ), C. glaubrechti forms a single clade with the other rock dwellers C. striata and C. woltereckae , 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. 7. Caridina glaubrechti from the Malili lake system. A. Distribution. B. Colour pattern of living animal (not to scale). Picture courtesy of Chris Lukhaup.

Fig. 8. Caridina glaubrechti from the Malili lake system. A. Cephalothorax and cephalic appendages, female (ZMB 29053); B. Preanal carina, male (ZMB 29109); C. Uropodal diaeresis, female (ZMB 29053); D. Scaphocerite, male (ZMB 29109); E. Dactylus of third pereiopod, female (ZMB 29074), F. Telson, female (ZMB 29053); G. Telson, another female (ZMB 29053); H. Third pereiopod, female (ZMB 29074); I. Dactylus of fifth pereiopod; J. Fifth pereiopod; K. Endopod of male first pleopod (ZMB 29109); L. Appendix masculina of male second pleopod; M. Distal end of telson, female (ZMB 29053); N. Distal end of telson, another female (ZMB 29053); O. First pereiopod, female (ZMB 29053); P. Second pereiopod; Q. SEM image of chela and carpus of first and second pereiopods, female (ZMB 29053). Scale bars: A, D = 1.0 mm; B, F-H, J-L, O-Q = 0.5 mm; C, E, I, M-N = 0.1 mm.

Fig. 9. Caridina glaubrechti from the Malili lake system. A. Mandible (ZMB 29053); B. Maxillula; C. Maxilla; D. second maxilliped; E. third maxilliped; F. first maxilliped. Scale bars: A-F = 1mm.

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. 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).