Caridina longidigita, Cai & Wowor, 2007

Cai, Yixiong & Wowor, Daisy, 2007, Atyid Shrimps From Lake Poso, Central Sulawesi, Indonesia With Description Of A New Species (Crustacea: Decapoda: Caridea), Raffles Bulletin of Zoology 55 (2), pp. 311-320 : 317-320

Caridina longidigita , new species

( Figs. 4 , 5 )

Material examined. – Holotype: male, cl 3.2 mm, MZB CRU- 1642 , west coast of Lake Poso at Taipa area , Kab. Poso, Sulawesi Tengah, rocky shore with sand substrate, coll. C. Schubart et al., 22 Jan.2000.

Paratypes: 1 ovigerous female, cl 3.2 mm, MZB CRU-1643 , data same as holotype ; 11 males, cl 2.3–3.2 mm, 4 females, cl 2.3–2.9 mm, 1 ovigerous female, cl 3.0– 3.2 mm, ZRC 2007.0476 , data same as holotype. Others : 1 male, cl 3.5 mm, MZB CRU-1644 , Lake Poso , coll. D. Wowor, Oct.1999 ; 1 female, cl 3.0 mm, ZRC 2007.0477 , Sungai Poso at the outlet of Lake Poso , across the new bridge at rocky cliff, Tentena, Kab. Poso, Sulawesi Tengah, Indonesia, coll. C. Schubart et al., 22 Jan.2000 ; 19 males, cl 2.9–3.9 mm, 10 females, cl 3.5–3.6 mm, ZRC 2007.0478 , east coast of Lake Poso at Desa Besuna, Kab. Poso, Sulawesi Tengah, rocky area, coll. C. Schubart et al., 22 Jan.2000 .

Description. – Rostrum reaching near to or slightly beyond end of scaphocerite, upturn anteriorly, armed dorsally with 12–21 teeth on posterior 1/2–3/4, including 3–6 on carapace posterior to orbital margin, armed ventrally with 10–18 teeth. Antennal spine placed lower than inferior orbital angle. Pterygostomian margin broadly rounded.

Sixth abdominal segment ca. 0.5 times as long as carapace, shorter than telson, twice as long as fifth segment. Preanal carina with a spine. Telson 3.1 times as long as wide, not terminating in a projection, with 4 pairs of dorsal spinules on distal half of telson, with 4 pairs of distal spines, lateral pair longer than intermediates, median pair shortest. Preanal carina with a spine.

Eyes well developed, anterior end reaching to 0.8 times length of basal segment of antennular peduncle. Antennular peduncle 0.86 times as long as carapace; basal segment of antennular peduncle as long as combined length of second and third segments, anterolateral angle pointed, reaching to 0.4 times length of second segment, second segment about twice as long as third segment. Stylocerite reaching near end of basal segment of antennular peduncle. Scaphocerite 4.2 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 slender and elongated, scaphognathite tapering posteriorly with numerous long, curved setae at posterior end. Palp of first maxilliped ending in a broad triangular form. Podobranch of second maxilliped reduced to be a lamina. Third maxilliped reaching to end of second segment of antennular peduncle, with ultimate segment shorter than penultimate segment.

Epipods absent from all pereiopods. First pereiopod reaching slightly beyond end of second segment of antennular peduncle, merus 4.7 times as long as wide, shorter than carpus; carpus slightly excavated anteriorly, 5.2 times as long as high, as long as chela; chela 4.5 times as long as broad, fingers 3.5 times as long as palm. Second pereiopod reaching to end of second segment of antennular peduncle, merus 6.0 times as long as wide, shorter than carpus; carpus 5.4 times as long as high, as long as chela; chela 4.9 times as long as broad, fingers 3.5 times as long as palm. Third pereiopod reaching to end of antennular peduncle; propodus 11 times as long as wide, 5.2 times as long as dactylus; dactylus 2.3 times as long as wide (spines included), with 4–6 spines on flexor margin. Fifth pereiopod reaching to end of second segment of antennular peduncle; propodus 13 times as long as wide, 4.6 times as long as dactylus; dactylus 2.8 times as long as broad, with 27–32 spinules on flexor margin.

Endopod of male first pleopod subtriangular, 0.3 times length of exopod, no appendix interna. Appendix masculina of male second pleopod short, reaching to half length of endopod, appendix interna short, about 0.3 times length of appendix masculina.

Uropodal diaeresis with 11–14 movable spinules.

Habitat. – Lakes. This species is only found on rocky substrates in Lake Poso.

Etymology. – The species name combines two Latin words, “ long ” and “ digita” referring to the extremely long fingers. Name is used as a noun in apposition.

Remarks. – With regard to the form of the rostrum, C. longidigita is very similar to C. sarasinorum , but it can easily be separated by the extra long and slender fingers of the chelae of the first and second pereiopods (3.5 times as long as their respective palms vs. subequal to palm). This character makes C. longidigita very different from all the other members in the genus Caridina . Other than this, C. longidigita also differs from C. sarasinorum in having fewer spinules on the dactylus of the fifth pereiopod (27–32 vs. 48–50) and the absence of epipods on all the pereiopods (see Figs. 6E, F, vs. Figs. 4G, H ).

Distribution. – Sulawesi (Lake Poso).

Figures

Fig. 4. Caridina longidigita, new species: A, 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 preanal carina; L, diaeresis. Scale bars: A, D = 1 mm; B, E–K = 0.5 mm; C, L = 0.2 mm. (paratype, ZRC 2007.0748).

Fig. 5. Caridina longidigita, new species: A, first pereiopod; B, second pereiopod; C, third pereiopod; D, dactylus of third pereiopod; E, fifth pereiopod; F, dactylus of fifth pereiopod; G, endopod of male first pleopod; H, appendix masculina and appendix interna of male second pleopod. Scale bars: A–C, E = 0.5 mm; D, F = 0.1 mm; G, H = 0.2 mm. (paratype, ZRC 2007.0748).