Caridina masapi Woltereck, 1937a

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 : 387-392

Caridina masapi Woltereck, 1937a

( Figs. 24–26 ; Table 10)

Caridina Masapi Woltereck, 1937a: 223 , Figs. I.6 a-h, pls. 3,6 (type locality: Matanno [Matano] islands, Lake Towuti, Lake Mahalone [Mahalona], Lake Wawontoa [Lontoa], Lake Masapi, small stream between Lake Matanno and Lake Mahalone).

Caridina masapi – Woltereck, 1937b: 306, fig. 10; Chace, 1997: 16; Fernandez-Leborans et al., 2006b: 1985, Table I; von Rintelen et al., 2008: 2244, Table 1; Cai et al., 2009: 21, Figs. 4-5 (type locality of neotype: southern shore of Lake Masapi).

Cardina masapi – Brooks, 1950: 168 (erroneous spelling).

Material examined. – Lake Lontoa : 74 ex. ( MZB Cru 1689, n=37; ZMB 29038, n=37, some SEM material), southeast shore, 02°40.4'S, 121°43.35'E, loc. 92-03, on mixed substrate, coll. K. & T. von Rintelen, 3 Oct.2003 ; 16 ex. ( MZB Cru 1690, n=8; ZMB 29045, n=8, some SEM material), southwest shore, 02°40.48'S, 121°43.06'E, loc. 93-03, on macrophytes, coll. K. & T. von Rintelen, 3 Oct.2003 .

Lake Matano – 13 ex. ( MZB Cru 1692), south shore, near cave entrance, 02°29.85'S, 121°18.66'E, loc. 60-03, on mixed substrate, coll. K . & T. von Rintelen , 24 Sep.2003 ; 5 ex. ( ZMB 29083, n=5 and few juveniles), Petea River , approx. 400 m east of Lake Mahalona, 02°34.41'S, 121°30.63'E, loc. 54-03, on mixed substrate, coll. K . & T. von Rintelen , 23 Sep.2003 ; 27 ex. ( MZB Cru 1702, n=14; ZMB 29276, n=13), Petea River, approx. 1.8 km north of Lake Mahalona, 02°34.15'S, 121°31.4'E, loc. F2-04, substrate unknown, coll. F. Herder, 31 Mar.2004 ; 9 ex. ( MZB Cru 1703, n=4; ZMB 29280, n=5), Petea River, 02°34.17'S, 121°31.21'E, loc. F3-04, substrate unknown, coll. F. Herder, 31 Mar.2004 .

Lake Masapi – 170 ex. ( MZB Cru 1693, n=70; ZMB 29035, n=100, some SEM material), south shore, 02°50.84'S, 121°21.09'E, loc. 47-03, on mixed substrate, coll. K. & T. von Rintelen, 20 Sep.2003 ; 81 ex. ( MZB Cru 1694, n=62; ZMB 29277, n=19, some SEM material), south shore, 02°50.837'S, 121°21.116'E, loc. F5-04, on mixed substrate, coll. F. Herder, 15 Apr.2004 .

Lake Towuti – 1 ex. ( ZMB 29031, n=1 and some juveniles), east shore, 02°40.84'S, 121°41.32'E, loc. 87-03, on Ottelia , coll. K . & T. von Rintelen , 2 Oct.2003 ; 14 ex. ( MZB Cru 1695, n=7; ZMB 29046, n=7, some SEM material), north shore, at cape, 02°39.38’S, 121°29.73'E, loc. 67-03, on rocks in shallow water, coll. K . & T. von Rintelen , 26 Sep.2003 ; 1 ex. ( ZMB 29117), 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 , 3 Mar.2003 ; 2 ex. ( ZMB 29281), 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 ; 2 ex. ( ZMB 29284), northwest shore, 02°40.647'S, 121°24.915'E, loc. 142-04, on leaf litter, coll. K . & T. von Rintelen , 25 Jul.2004 ; 7 ex. ( ZMB 29285), 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 ; 3 ex. ( MZB Cru 1696), 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 ; 1 ex. ( MZB Cru 1697), southwest shore, Cape Sioloya, 02°50.7'S, 121°26.32'E, loc. 77-03, on leaf litter, coll. K . & T. von Rintelen , 28 Sep.2003 ; 39 ex. ( MZB Cru 1699, n=39), Larona River, close to outlet bay of Lake Towuti, 02°45.8'S, 121°20.8'E, loc. 51-03, on macrophytes, coll. K . & T. von Rintelen , 21 Sep.2003 ; 54 ex. ( MZB Cru 1701, n=27; ZMB 29195, n=27), Towuti catchment, stream at road Wawondula-Timampu, 02°38.47'S, 121°22.76'E, loc. 39-03, on mixed substrate, coll. K . & T. von Rintelen , 16 Sep.2003 ; 4 ex. ( ZMB 29448), Lemolemo River , 02°42.62'S, 121°40.99'E, loc. 85-03, on leaf litter, coll. K . & T. von Rintelen , 2 Oct.2003 .

Lampesue River (Malili lake system) – 44 ex. ( MZB Cru 1698, n=22; ZMB 29047, n=22), 02°35.4'S, 121°39.85'E, loc. 79-03, on leaf litter, coll. K. & T. von Rintelen, 29 Sep.2003 .

Tominanga River (Lake Mahalona) – 3 ex. ( ZMB 29072), approx. 1.5 km east of Lake Mahalona, 02°38.73'S, 121°31.95'E, loc. 59- 03, on leaf litter, coll. K. & T. von Rintelen, 23 Sep.2003 ; 3 ex. ( ZMB 29209), approx. 2.2 km north of Lake Towuti , 02°36.5'S, 121°31.78'E, loc. 58-03, on leaf litter, coll. K. & T. von Rintelen, 23 Sep.2003 .

Description. – Carapace length 2.1-4.6 mm (n=56). Rostrum ( Fig. 25 A-C, Table 10) shorter than antennular peduncle to slightly reaching beyond end of scaphocerite, 0.6-1.3 times as long as carapace (n=56), armed dorsally with 7-21 teeth (including 2-5 teeth posterior to orbital margin), approx. anterior third unarmed or with few teeth widely spaced, armed ventrally with 3-10 teeth. Antennal spine situated below inferior orbital angle. Pterygostomial angle broadly rounded. Eyes well developed, anterior end 0.6-0.7 times length of basal segment of antennular peduncle (n=5). Antennular peduncle 0.8-1.0 times as long as carapace (n=5), second segment 1.7-2.4 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. 25E ) 3.2-4.5 times as long as wide (n=5).

Sixth abdominal somite 0.4-0.7 times length of carapace (n=56), 1.4-2.1 times as long as fifth somite (n=21), 0.8-1.1 times length of telson (n=37). Telson ( Fig. 25I,L ) 2.9-3.6 times as long as wide (n=6), 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, sometimes with one median spine, lateral pair distinctly longer than intermediate spines, median spine or pair of spines usually shortest. Preanal carina ( Fig. 25D ) with a spine. Uropodal diaeresis ( Fig. 25F ) with 10-14 movable spinules (n=6).

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. 26A ) ending in a row of 7-8 small teeth, molar process truncated. Lower lacinia of maxillula ( Fig. 26B ) broadly rounded, upper lacinia elongate, with numerous distinct teeth and setae on inner margin, palp slender. Upper endites of maxilla ( Fig. 26C ) subdivided, palp slender, short, scaphognathite tapering posteriorly with numerous long, curved setae at posterior end. Distal end of palp of first maxilliped ( Fig. 26F ) triangular, with a finger-like projection; flagellum of the exopod very stout, endopod high, but not exceed the flagellum of exopod in length. Second maxilliped ( Fig. 26E ) typical. Third maxilliped ( Fig. 26D ) 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. 25 M-O); chela of first pereiopod 1.9-2.9 times as long as wide (n=25), 0.9-1.3 times length of carpus (n=56); tips of fingers rounded, without hooks; dactylus 1.1-1.3 times as long as palm (n=12); carpus 2.1-4.6 times as long as wide (n=25), 1.1-1.3 times length of merus (n=5). Chela of second pereiopod 2.4-3.9 times as long as wide (n=25), 0.6-1.6 times length of carpus (n=55); tips of fingers rounded, without hooks, dactylus 1.2-1.5 times as long as palm (n=12); carpus 5.0-8.1 times as long as wide (n=25), 1.4-1.6 times as long as merus (n=5).

Third pereiopod ( Fig. 25 G-H) slender, dactylus 3.5-5.9 times as long as wide (terminal spine included, without spines of flexor margin; n=5), terminating in one large claw with 3-7 accessory spines on flexor margin; propodus 12.6-14.8 times as long as wide, 2.9-5.0 times as long as dactylus; carpus 5.4-6.9 times as long as wide, 0.5-0.6 times as long as propodus, 0.5-0.6 times as long as merus; merus 8.1-11.0 times as long as wide, bearing 3-4 strong, movable spines on posterior margin of outer surface.

Fifth pereiopod slender ( Fig. 25 J-K), dactylus 5.7-7.0 times as long as wide (terminal spine included, without spines of flexor margin; n=5), terminating in one large claw with 30- 44 accessory spines on flexor margin; propodus 11.6-15.3 times as long as wide, 2.6-3.3 times as long as dactylus; carpus 5.0-5.9 times as long as wide, 0.5 times as long as propodus, 0.6 times as long as merus; merus 9.0-9.8 times as long as wide, bearing 3 strong, movable spines on posterior margin of outer surface.

Endopod of male first pleopod ( Fig. 25Q ) elongated triangular, 2.0-2.7 times as long as proximally wide (n=5), without appendix interna. Appendix interna of male second pleopod ( Fig. 25R ) 0.8-0.9 times as long as appendix masculina (n=5).

Ovigerous females with 15- 41 eggs (n= 3 females); egg size 0.7-1.2 x 0.5-0.7 mm (n=54, eggs with and without eyes).

Distribution. – C. masapi is endemic to the Malili system, where it is widely distributed in the lakes and rivers ( Fig. 24 ). Although there is only a single collecting site from Lake Matano, and none directly from Lake Mahalona, Woltereck (1937a: 223,b: 306) reports this species from another locality in Lake Matano (“Matanno islands”), which are further west of the current collecting site on the south coast) and Lake Mahalona. So far, it is the only shrimp species occurring in Lake Masapi and Lake Lontoa.

Biology and ecology. – C. masapi , similarly to C. lanceolata , was found on various kinds of often mixed, but mainly soft substrate (e.g. macrophytes and leaf litter). Thus, it seems rather to be a generalist with a respective feeding strategy (compare von Rintelen et al., in review). The cheliped morphology does not show any conspicuity, unlike in most other species from the Malili lakes (for example the unusually slender pereiopods in C. lingkonae , C. spinata , and C. profundicola ).

Colour pattern. – Yellowish or brownish to transparent, often with transversal dark or light bands, but without an always equally pronounced pattern. The colouration resembles that of many riverine Caridina species from Sulawesi, which are either dark (brownish) or lightly (yellowish-transparent) coloured. Large (often ovigerous) females usually appear darker than smaller specimens.

Taxonomic remarks. – Cai et al. (2009: 19) stated: “Specimens of Woltereck (1937a, b) are no longer extant […]. As all new species described by Woltereck are morphologically close to each other and to stabilize the taxonomic status of those species, neotypes are designated if specimens are available from the recent collections”. Consequently, they designated a neotype for C. masapi from Lake Masapi (male, cl 2.9 mm, ZRC) (2009: 21) .

Here, C. masapi is regarded as a riverine species (that also enters the lakes) rather than a typical lacustrine species, because of its occurrence in all five lakes and the surrounding rivers. C. lanceolata is also widely distributed in the lakes (excluding Lake Masapi and Lake Lontoa), but does not occur in any tributary to the lakes. Thus, we here regard it as a lacustrine species. The rostrum superficially resembles C. loehae , but it appears less fragile and longer (usually overreaching end of second segment of antennular peduncle vs. not overreaching in C. loehae ). Furthermore, both species show a different number of spines on the dactylus of the fifth pereiopod (30-44, median 33 vs. 12-16, median 16 in C. loehae ). Also, C. masapi is similar to C. mahalona , the other riverine species of the Malili lake system, but the rostrum is not as variable as in C. mahalona and the anterior dorsal part is not always unarmed. It is generally smaller than C. mahalona (carapace length 2.1-4.6 mm, median 3.1 mm vs. 2.8-5.2 mm, median 4.4 mm in C. mahalona ) and differs by the number of teeth on the dactylus of the fifth pereiopod (vs. 39-57, median 52 in C. mahalona ). C. masapi can resemble C. holthuisi , but the rostrum in C. masapi usually differs by a conspicuous unarmed gap on the dorsal margin (sometimes with few teeth widely spaced) and a more slender and cambered shape (vs. usually straight and broader with a more or less thorough denticulation in C. holthuisi ).

C. masapi is genetically distinct from C. loehae and C. mahalona ( Figs. 63-64 ). C. masapi appears in two allopatric clades. One is restricted to Lake Masapi (MS; Fig. 64 ), the other one to several lakes and rivers. This might hint at the existence of cryptic species (compare von Rintelen et al., in review).

Figures

Fig. 24. Distribution of Caridina masapi in the Malili lake system.

Fig. 25. Caridina masapi from the Malili lake system. A. Cephalothorax and cephalic appendages, female (ZMB 29038); B. Cephalothorax and cephalic appendages, male (ZMB 29277); C. Woltereck’s drawings of the rostrum, from all Malili lakes (modified from 1937a); D. Preanal carina, female (ZMB 29277); E. Scaphocerite, F. Uropodal diaeresis, male (ZMB 29277); G. third pereiopod, female (ZMB 29277); H. Dactylus of third pereiopod; I. Telson, male (ZMB 29277); J. fifth pereiopod, female (ZMB 29277); K. Dactylus of fifth pereiopod; L. Distal end of telson, male (ZMB 29277); M. First pereiopod; N. Second pereiopod; O. SEM image of chela and carpus of first and second pereiopods; P. Endopod of male first pleopod; Q. Appendix masculina of male second pleopod. Scale bars: A-B, E = 1.0 mm; D, G, I-J, M-Q = 0.5 mm; F, H, K-L = 0.1 mm; C = no scale available.

Fig. 26. Caridina masapi from the Malili lake system. A. Mandible (ZMB 29277); B. Maxillula; C. Maxilla; D. third maxilliped; E. second maxilliped; F. first maxilliped. Scale bars: A-F = 1mm.

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. 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. 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).