Caridina mahalona, Cai, Yixiong, Wowor, Daisy & Choy, Satish, 2009

Cai, Yixiong, Wowor, Daisy & Choy, Satish, 2009, Partial revision of freshwater shrimps from Central Sulawesi, Indonesia, with descriptions of two new species (Crustacea: Decapoda: Atyidae), Zootaxa 2045, pp. 15-32 : 29-32

Caridina mahalona , new species

( Figures 8 ; 9)

Material examined. Holotype: cl 4.2 mm, female, MZB Cru 2265, Lake Mahalona at southwest coast, coll. Kottelat & A. Werner, 16 Mar 1989. Paratypes: 2 males, cl 3.5–3.9 mm, 4 females, cl 3.5–4.4 mm, 2 ovigerous females, cl 4.4–4.5 mm, eggs 0.95x 0.60 mm, ZRC, same data as holotype.

Description. Rostrum short, reaching to middle of second segment of antennular peduncle, or near to end of this segment, anterior 1/3 upturned strongly, rostral formula: 4-5+8-12/1-7, unarmed on anterior third of dorsal margin. Antennal spine placed slightly below inferior orbital angle. Pterygostomian margin broadly rounded.

Sixth abdominal somite 0.57 times of carapace, 2.0 times as long as fifth somite, distinctly shorter than telson. Telson 3.4 times as long as wide, not terminating in a projection, with 4 pairs of dorsal spinules and one pair of dorsolateral spinules; distal end with about 4 pairs of spines, lateral pair longer than intermediate pairs, median pair shortest. Preanal carina with a spine.

Eyes well developed, anterior end reaching to 0.7 times length of basal segment of antennular peduncle. Antennular peduncle 0.63–0.67 times as long as carapace; basal segment of antennular peduncle longer than sum of second and third segment lengths, anterolateral angle reaching 0.25 times length of the second segment, second segment about 2 times as long as third segment. Stylocerite reaching 0.8 times length of basal segment of antennular peduncle. Scaphocerite 4.0 times as long as wide.

Incisor process of mandible ending in irregular teeth, molar process truncated. Lower lacinia of maxillula broadly rounded, upper lacinia elongated, with a number of distinct teeth on inner margin, palp slender. Upper endites of maxilla subdivided, palp elongated, scaphognathite tapering posteriorly with numerous long, curved setae at posterior end. Palp of first maxilliped rounded, ending in a prominent finger-like projection. Podobranch of second maxilliped reduced to a lamina. Third maxilliped reaching to end of segment of antennular peduncle, with ultimate segment distinctly shorter than penultimate segment.

Epipod present on first pereiopod, lacking from last four pereiopods. First pereiopod reaching to end of basal segment of antennular peduncle; merus 2.3 times as long as broad, shorter than carpus; carpus excavated anteriorly, as long as chela, 3.5 times as long as high; chela 2.5 times as long as broad; fingers 1.4 times as long as palm. Second pereiopod reaching beyond end of second segment of antennular peduncle; merus distinctly shorter than carpus, 5.0 times as long as broad; carpus 1.5 times as long as chela, 7.3 times as long as high; chela 3.3 times as long as broad; fingers 1.5 times as long as palm. Third pereiopod reaching to end of scaphocerite, propodus 13 times as long as broad, 3.8 times as long as dactylus; dactylus 3.4 times as long as wide (spines included), terminating in 1 claw, with 4–6 accessory spines on flexor margin. Fifth pereiopod reaching to end of second segment of antennular peduncle, propodus 13 times as long as broad, 3.2 times as long as dactylus, dactylus 4.0 times as long as wide (spinules included), terminating in 1 claw, with 42–55 spinules on flexor margin. Endopod of male first pleopod sub-rectangular, with no appendix interna, 0.25 times length of exopod. Appendix masculina of male second pleopod slender, half length of endopod, appendix interna slender, 0.4 times length of appendix masculina.

Uropodal diaeresis with 12–13 movable spinules.

Eggs 0.75x 0.50 mm in diameter.

Habitat. Lake.

Remarks. Caridina mahalona resembles C. laevis Heller, 1862 , from Java, and C. opaensis from Sulawesi. It can be distinguished from C. laevis by the dactylus of third pereiopod not showing sexual dimorphism as in C. laevis , the shorter dactylus of the fifth pereiopod (propodus 3.2 times as long as dactylus vs. 2.0–2.3 times) and the smaller number of spinules on the dactylus of the fifth pereiopod (42–55 vs. 80–95 in C. laevis ). It differs from C. opaensis by the form of rostrum, which is distinctly upturned along the anterior 1/3, the shorter antennular peduncle which is 0.63–0.67 times as long as the carapace (vs. 0.79–0.82 times in C. opaensis ), the wider scaphocerite (4.0 times as long as wide vs. 4.6 times in C. opaensis ), and the absence of epipods on the last four pereiopods (vs. absent in last three in C. opaensis ).

Distribution. Known only from Lake Mahalona , Central Sulawesi, Indonesia.

Figures

FIGURE 8. Caridina mahalona, new species A, I. cephalothorax and cephalic appendages, B. telson, C. distal portion of telson; D. scaphocerite, E. mandible, F. maxillula; G. maxilla, H. first maxilliped, I. second maxilliped, J. third maxilliped, K. diaeresis. Scales: A, L = 1 mm; B, E – J = 0.5 mm; C, K = 0.2 mm. (A – K, paratype, male, cl 3.9 mm, L. holotype, female, cl 4.2 mm, MZB Cru 2265)