Caridina conghuensis Klotz & Rintelen, 2014, sp. nov.

Caridina conghuensis sp. nov.

(Figs. 12, 13, colour plate 1)

Material examined. Holotype ♂ cl 3.9 mm (OUMNH.ZC 2013-07-024), China, Guangdong Province, swampy area near Conghua City, 23.57495°N 113.43740°E, coll. W. + M. Klotz 21.03.2010. Paratypes 2 ♂ cl 3.0 and 3.1 mm, 2 ♀ cl 3.9 and 4.6 mm (OUMNH.ZC 2013-07-025); 3 ♂ cl 3.1–3.7 mm, 2 ♀ cl 3.4–4.2 mm (ZMB 28225; Präp. 5053–5054); 2 ♂ cl 3.0 and 3.5 mm, 1 ♀ cl 3.9 mm (ZRC 2013.1745); 2 ♂ cl 2.9 and 5.0 mm, 1 ♀ cl 3.7 mm (RMNH. CRUS.D.56057), same data as holotype; 3 ♀ cl 3.1–3.3 mm (ZRC 2013.1746); 3 ♀ cl 2.0– 3.6 mm, 1 ♂ cl 2.6 mm (OUMNH.ZC 2013-07-026); 1♂ 3.0 mm, 3 ♀ cl 3.5–3.6 mm (ZMB 28226; Präp. 5055–5056); 2 ♀ cl 2.6 and 3.5 mm (RMNH. CRUS.D.56058), China, Guangdong Province, swampy area near Conghua City, 23.57495°N 113.43740°E, coll. W. + M. Klotz 0 1.04.2012.

Comparative material examined.

Description. Cephalothorax and cephalic appendages. Rostrum (Fig. 12 A, B), straight, slightly directed downwards, tip slightly directed upwards, reaching to midlength or end of second segment of antennular peduncle, 0.36–0.47 (median 0.42) times as long as carapace, rostrum formula 3–5 + 7–9 / 2–4. Inferior orbital angle nearly fused with an antennal spine. Pterygostomial angle rounded, slightly produced forward. Eyes well developed with globular cornea. Antennular peduncle (Fig. 12 A, C) 0.51–0.59 (median 0.53) times as long as carapace, first segment 2.08–2.42 (median 2.30) times as long as second segment, second segment 1.60–12.32(median 1.90) times longer than third segment. Stylocerite reaching to about midlength of second segment of antennular peduncle. Scaphocerite (Fig. 12 D) 2.93–3.44 (median 3.13) times as long as wide.

Abdominal somites, telson and uropods. Sixth abdominal somite 0.48 times carapace length, 0.94 times as long as telson. Telson (Fig. 12 E, F) with distal margin convex with or without a median projection, with 3–4 pairs of short spiniform setae dorsal and one pair of short spiniform setae dorsolateral; distal end with 8–9 strong spiniform setae, sublateral pair shorter than lateral and inner pairs. Preanal carina (Fig. 12 G) high, rounded, lacking a spine, with few setae. Uropodal diaeresis (Fig. 12 H) sigmoid, with 17–21 movable spiniform setae, outermost ones slightly shorter than lateral angle.

Mouthparts and branchiae. Incisor process of mandible (Fig. 12 I) ending in irregular teeth, molar process truncated. Lower lacinia of maxillule (Fig. 12 J) broadly rounded, upper lacinia elongate, with numerous distinct cuspidate setae on inner margin, palp slender with few simple setae and one cuspidate seta near tip. Upper endites of maxilla (Fig. 12 K) subdivided, palp slender, scaphognathite tapering posteriorly, fringed with long, curved setae at posterior margin. Palp of first maxilliped (Fig. 12 L) ending in a blunt triangular extension. Podobranch on second maxilliped (Fig. 12 M) well developed. Third maxilliped (Fig. 12 N) with 2 arthrobranches, ultimate segment as long as penultimate. First pereiopod with an arthrobranch. Pleurobranchs present on all pereiopods. Well-developed (with hooks on distal end) epipods present on third maxilliped and first 4 pereiopods.

Pereiopods. Chela and carpus of first pereiopod stouter and broader than chela and carpus of second pereiopod (Fig. 13 A, B); chela of first pereiopod 1.89–2.16 (median 2.11) times as long as wide, 1.29–1.44 (median 1.31) times length of carpus; tips of fingers rounded, without a visible hook in adult specimens, 0.89–1.23 (median 0.98 times as long as palm; carpus deeply excavated distally 1.42–1.85 (median 1.54) times as long as wide, 0.89–1.03 (median 0.92) times length of merus. Merus 1.52–3.00 (median 2.56) times as long as wide, longer than ischium. Chela of second pereiopod 2.76–2.92 (median 2.86) times as long as wide, 0.65–0.80 (median 0.78) times length of carpus; tips of fingers rounded, without hooks, dactylus 1.31–1.37 (median 1.33) times as long as palm; carpus 5.00–5.58 (median 5.37) times as long as wide, 1.08–1.23 (median 1.16) times as long as merus; merus 4.56–5.22 (median 4.96) times as long as wide, longer than ischium. Third pereiopod (Fig. 13 C, D) slender, not sexually dimorphic, dactylus 3.07–3.83 (median 3.23) times as long as wide (terminal claw and spines on flexor margin included), terminating in one large claw with 5–7 accessory spiniform setae on flexor margin; propodus 8.63–9.67 (median 8.80) times as long as wide, 3.02–3.37 (median 3.15) times as long as dactylus; carpus 3.80–5.00 (median 4.57) times as long as wide, 0.67–0.76 (median 0.74) times as long as propodus, 0.50–0.56 (median 0.52) times as long as merus; merus 5.49–6.15 (median 5.97) times as long as wide, 1.79–1.99 (median 1.92) times as long as carpus, bearing 3 or 4 strong spiniform setae on posterior margin of outer surface. Ischium mostly with 1 spiniform seta. Fifth pereiopod (Fig. 13 E, F) slender, dactylus 3.33–3.87 (median 3.45) times as long as wide (terminal claw and spinuliform setae on flexor margin included), terminating in one large claw with 36–40 spinuliform setae on flexor margin; propodus 10.00–12.29 (median 11.07) times as long as wide, 3.02–3.51 (median 3.04) times length of dactylus, carpus 4.05–4.52 (median 4.45) times as long as wide, 0.54–0.56 (median 0.55) times as long as propodus, 0.63–0.69 (median 0.65) times as long as merus; merus 5.24–6.68 (median 6.27) times as long as wide, 1.46–1.58 (median 1.54) times length of carpus, bearing 2 or 3 strong spiniform setae on posterior margin of outer surface. Ischium without a strong spiniform seta.

Pleopods. Endopod of male first pleopod (Fig. 13 G, H) subrectangular, anterior region not or just slightly bent backwards, inner margin slightly concave, distal part not dilated, 2.63–3.12(median 2.87) times as long as distal width, 0.59–0.62 (median 0.60) times as long as exopod, with appendix interna arising near and reaching beyond distal margin of endopod. Appendix masculina on male second pleopod (Fig. 13 I) slender, club-shaped, 5.00–5.42 times as long as wide, with long spinuliform setae on inner and distal margin, few smaller spiniform setae on basal part, appendix interna reaching to about 0.76–0.79 of appendix masculina.

Size. Postorbital carapace length 3.0– 4.6 mm.

Coloration. As shown in colour plate 1H; in females body dark, bluish or blackish, with some weak white transversal stripes on rostrum, abdominal segments and tail fan.

Reproductive biology. Ovigerous females with few large eggs (W. Klotz, pers. obs.); exact size not measured.

Etymology. Caridina conghuensis n. sp. is named after the type locality, a swampy area near Conghua city, Guangdong Province, Southern China.

Remarks. Caridina conghuensis n. sp. is similar to C. cantonensis in having a medium short rostrum reaching about midlength of second antennular peduncle, and length of dactylus of first cheliped resembles about length of palm. In addition to the dark life coloration of adult females which allows to distinguish these species in the field, C. conghuensis n. sp. could be distinguished from C. cantonensis by the shape of the rostrum with tip lightly directed upwards in C. conghuensis n. sp. vs. tip straight in C. cantonensis, the pterygostomial margin of the carapace with is just slightly produced forward vs. distinctly produced forward in C. cantonensis. The anterior region of the endopod of first pleopod in males is not bent backwards, the appendix interna overreaching distal margin of endopod vs. anterior region strongly bent backwards, appendix interna not overreaching distal margin of endopod in C. cantonensis. The endopod is more slender, 2.63–3.12 median 2,87 times as long as distal wide vs. 2.13–2.35, median 2.26 times as long as wide in C. cantonensis. The appendix masculina on second pleopods of male is more slender, 5.00–5.42 median 5.21 times as long as wide, 0.64–0.66 median 0.65 times as long as exopod vs. 3.73–4.26 median 4.09 times as long as wide, 0.52–0.59 median 0.56 times as long as exopod in C. cantonensis. The dactyli of 3rd periopods are longer in relation to the propodi (ratio datylus lenght to propodus length 0.30–0.33 median 0.32 vs. 0.23–0.28 median 0.26 in C. cantonensis), propodi of 3rd and 5th pereiopod are somewhat stouter (length to width ratio 8.63–9.67 median 8.80 and 10.00–12.29 median 11.07 vs. 9.29–12.90 median 10.37 and 11.22–14.77 median 12.50 in C. cantonensis).

From C. mariae n. sp., which occurs sympatric with C. conghuensis n. sp., the latter can be distinguished by the number of teeth on the ventral margin of the rostrum (2–4 teeth vs. 1–2 in C. mariae n. sp.), the shape of the rostrum (tip slightly directed upwards vs. straight in C. mariae n. sp.) the shorter stylocerite (reaching to about 0.5 of second segment of antennular peduncle vs. reaching to at least 0.7, mostly to end of this segment in C. mariae n. sp.). The endopod of males first pleopod is more slender (length to width ratio 2.63–3.12), not ditated in distal part, the appendix interna overreaching distal margin of endopod vs. more stout (length to width ratio 2.37–2.70), clearly dilated at the distal part of outer margin in full-grown male specimens, appendix interna reaching to distal margin of endopod in C. mariae n. sp. The appendix masculina on second pleopods of male is more slender, 5.00–5.42 median 5.21 times as long as wide, 0.64–0.66 median 0.65 times as long as exopod vs. 3.94–5.09 median 4.00 times as long as wide, 0.55–0.63 median 0.58 times as long as exopod in C. mariae n. sp. The length of the dactylus of second cheliped in relation to the propodus is 1.31–1.37 vs. 1.49–1.79 in C. mariae n. sp. The dactyli of 3rd periopods are longer in relation to the propodi (ratio datylus length to propodus length 0.30–0.33 median 0.32 vs. 0.26–0.31 median 0.28 in C. mariae n. sp.), the propodi of 3rd pereiopod are somewhat stouter (length to width ratio 8.63–9.67 median 8.80 vs. 9.72–11.38 median 10.21 in C. mariae n. sp. In the field the two species could be distinguished by the dark body coloration of females of C. conghuensis n. sp. vs. striped coloration in both sexes of C. mariae n. sp.

Distribution and habitat. Caridina conghuensis n. sp. is known from a small swampy area near Conghua, Guangdong province, Southern China. The specimens were collected in pads of moss or small rivulets in dense vegetation of grass and bamboo. C. conghuensis n. sp. occurs sympatric with C. cantonensis and Caridina mariae n. sp. The dark life coloration of C. conghuensis n. sp. is helpful to distinguish it from the other two congeners at the type locality in the field. Following water parameters were recorded at the swampy habitat near Conghua: pH 7.0; conductivity 40 µS.