Caridina logemanni, Klotz, Werner & Rintelen, Thomas Von, 2014

Klotz, Werner & Rintelen, Thomas Von, 2014, To “ bee ” or not to be — on some ornamental shrimp from Guangdong Province, Southern China and Hong Kong SAR, with descriptions of three new species, Zootaxa 3889 (2), pp. 151-184 : 152-165

Caridina logemanni n. sp.

( Figs. 1–7 , colour plate 1, 3)

Material examined. Holotype ♂ cl 5.8 mm ( OUMNH.ZC 2013-07-001), Hong Kong, New Territories, small hill stream, exact location stored with type material to protect population in its natural habitat, coll. W. Klotz 19.03.2011. Paratypes 3 ♀ cl 6.4–6.7 mm, 1 ov. ♀ cl 6.7 mm, 1 ♂ cl 5.6 mm, 2 juv. cl 2.0 and 2.2 mm ( OUMNH.ZC 2013-07-002); 1 ♀ cl 6.9 mm, 1 ♂ cl 3.8 mm (BCD, without collection number); 2 ♂ cl 5.2 and 5.6 mm, 1 ♀ cl 6.4 mm, 1 ov. ♀ cl 6.8 mm ( ZMB 28222; Präp. 5043-5046); 2 ♂ cl 5.2 and 5.5 mm, 1 ♀ cl 7.1 mm, 2 ov. ♀ cl 7.0 and 7.1 mm ( ZRC 2013.1741), same data as holotype; 2 ov. ♀ cl 5,0 and 5,8 mm, 3 ♀ cl 3.0– 5.6 mm, 2 ♂ 3.6 and 4.0 mm ( ZRC 2013.1742); 2 ov. ♀ cl 5.3 mm, 3 ♀ cl 3.3–5.4 mm, 2 ♂ cl 3.0 and 4.2 mm ( OUMNH.ZC 2013-07-003); 2 ov. ♀ cl 5.9 and 6.0 mm; 2 ♀ cl 3.7 and 6.0 mm; 2 ♂ 3.4 and 3.6 mm ( ZMB 28221); 3 ov. ♀ cl 5.7–6.6 mm, 2 ♀ cl 3.3 and 3.7 mm, 2 ♂ cl 3.7 and 4.0 mm ( RMNH. CRUS.D.56047), Hong Kong, New Territories, other small hill stream, exact location stored with type material to protect population in its natural habitat, coll. W. + M. Klotz 0 2.04.2012. Other material: 1 exuviae of spent female, larvae of first and second stage ( OUMNH.ZC 2013-07-004), Hong Kong, New Territories, other small hill stream, larvae reared in the laboratory.

Species Collection no. Locality COI 16S

Atya scabra ZMB DNA- 510 Panama, Rio Guarumo KP168822 EF489985

Australatya sp. collWK06-10 Taiwan - KP168717 OUMNH.ZC 2013-07-012 China, Lixi Town, loc. 2010-03 - KP168729 OUMNH.ZC 2013-07-011 China, Lixi Town, loc. 2010-05 - KP168728 OUMNH.ZC 2013-07-015 China, Qingyuan Town KP168802 KP168720 OUMNH.ZC 2013-07-015 China, Qingyuan Town KP168803 KP168721 OUMNH.ZC 2013-07-010 China, Zuhai KP168804 KP168722 OUMNH.ZC 2013-07-010 China, Zuhai KP168805 KP168723 OUMNH.ZC 2013-07-007 Hong Kong, loc. CH 14 KP168806 KP168724 RMNH. CRUS.D.56048 Hong Kong, loc. CH 16 KP168807 KP168725 OUMNH.ZC 2013-07-005 Hong Kong, loc. CH 17 KP168809 KP168726 OUMNH.ZC 2013-07-008 Hong Kong, Lantau Island KP168810 KP168727

Caridina conghuensis n. sp. ZMB 28225 China - KP168736 OUMNH.ZC 2013-07-025 China - KP168735

Caridina cf. elongapoda OUMNH.ZC 2013-07-041 Hong Kong KP168821 KP168733 OUMNH.ZC 2013-07-041 Hong Kong - KP168734

Caridina impensa ZMB DNA- 283 China KP168820 KP168741

Caridina logemanni n. sp. ZMB 28222 Hong Kong, stream 1 - KP168744 ZMB 28221 Hong Kong, stream 2 - KP168745

Caridina logemanni n. sp. "bee shrimp" ZMB DNA- 823 aquarium trade - KP168743

Caridina maculata OUMNH.ZC 2013-07-028 China, Lixi Town - KP168748 OUMNH.ZC 2013-07-029 China, Lixi Town, type loc. of C. venusta - KP168749 OUMNH.ZC 2013-07-029 China, Lixi Town, type loc. of C. venusta - KP168750 OUMNH.ZC 2013-07-027 China, Lixi Town, from type loc. - KP168746 OUMNH.ZC 2013-07-027 China, Lixi Town, from type loc. - KP168747 ......continued on the next page Comparative material examined. Caridina cantonensis Yu, 1938 3 ♂ cl 4.4–5.0 mm, 1 ♀ cl 5.9 mm, 2 ov. ♀ cl 5.6 and 6.7 mm ( OUMNH.ZC 2013-07-005), 3 ♂ cl 4.5–5.5 mm, 1 ov. ♀ cl 5.8 mm, 1 ♀ cl 5.8 mm (collWK 28- 09) Hong Kong, New Territories, stream at Ha Miu Tin, 22.503250°N 114.264278°E, coll. W+M Klotz, A. Karge & C. Lukhaup 08.04.2009; 1 exuviae of spent female, larvae of 1st and 2nd larval stage ( OUMNH.ZC 2013-07-006) Hong Kong, New Territories, stream at Ha Miu Tin, 22.503250°N 114.264278°E coll. W. + M. Klotz 04.04.2012; 4♂ cl 3.8–4.3 mm, 4 ♀ cl 3.9–5.4 mm, 2 ov. ♀ cl 5.9 and 6.5 mm ( OUMNH.ZC 2013-07-007), 1 ov. ♀ cl 6.9 mm ( RMNH. CRUS.D.56049) Hong Kong, New Territories, Lung Hang Stream 22.403472°N 114.320944°E, coll. W+M Klotz, A. Karge & C. Lukhaup 07.04.2009; 7 ♂ cl 3.0– 5.2 mm, 6 ♀ cl 3.9–5.3 mm, 1 ov. ♀ cl 5.3 mm ( RMNH. CRUS.D.56048) Hong Kong, New Territories, small stream near Sheung Miu Tin, 22.502333°N 114.260000°E, coll. W+M Klotz, A. Karge & C. Lukhaup 08.04.2009; 3 ♂ cl 4.0– 5.2 mm, 8 ♀ cl 3.7–5.1 mm, 1 ov. ♀ cl 5.4 mm ( OUMNH.ZC 2013-07-008) Hong Kong, Lantau Island, stream near Pui O, 22.248528°N 113.982750°E coll. W. + M. Klotz & A. Karge 09.04.2009; 1 ♂ cl 5.1 mm ( OUMNH.ZC 2013-07-009) Hong Kong, New Territories, Nam Chung, small rivulet below dam of Ping Nam Stream, 22.51439°N 114.20733°E coll. W. + M. Klotz 16.03.2011; 32 ♂ cl 3.1–5.0 mm, 11 ♀ cl 2.6–5.7 mm, 4 ov. ♀ cl 5.3–5.7 mm ( OUMNH.ZC 2013- 07-010), 16 ♂ cl 2.9–5.2 mm, 6 ♀ cl 2.7–5.6 mm ( RMNH. CRUS.D.56050) China, Guangdong Prov., Zuhai, Henquin Island, San Die Quan Spring, 22.113694°N 113.502778°E, coll. W. + M. Klotz 05.04.2009; 9 ♂ cl 3.9–5.5 mm, 5 ♀ cl 3.7–6.5 mm ( OUMNH.ZC 2013-07-011), 13 ♂ cl 3.4–5.0 mm, 10 ♀ cl 2.9–6.2 mm ( RMNH. CRUS.D.56051) China, Guangdong Prov., Lixi Town near Yingde, 23.90673°N 113.25213°E, (2010_05), type locality of C. tumida , coll. W.+ M. Klotz 19.3.2010; 6 ♂ cl 3.7–5.6 mm, 6 ♀ cl 3.5–5.2 mm, ( OUMNH.ZC 2013-07-012) China, Guangdong Prov., Lixi Town near Yingde, 23.90590°N 113.24574°E, coll. W+M. Klotz and A. Karge 18.3.2010; 6 ♂ cl 4.0–6.0 mm, 3 ♀ cl 4.4–5.7 mm, 1 ov. ♀ cl 8.0 mm ( OUMNH.ZC 2013-07-013), 6 ♂ cl 3.6–6.2 mm, 2 ♀ cl 5.5 and 6.2 mm, 1 ov. ♀ cl 7.6 mm ( RMNH. CRUS.D.56052), China, Guangdong Prov., Lixi Town near Yingde, 23.90951°N 113.25970°E, loc. 2010_06, coll. W. + M. Klotz 19.03.2010; 1 ♂ cl 4.1 mm ( OUMNH.ZC 2013-07-014) China, Guangdong Province, swampy area near Conghua City, 23.57495°N 113.43740°E, coll. W. + M. Klotz 21.03.2010; 8 ♂ cl 4.3–5.7 mm, 1 ♀ cl 6.4 mm, 1 ov. ♀ 5.9 mm ( OUMNH.ZC 2013-07-015) China, Guangdong Prov., mountain stream near Quing Yuan City, 23.56641°N 113.17765°E, coll. W. Klotz, Y. Cai & C. Lukhaup 01.04.2012; 1 ♂ cl 3.5 mm, 4 ♀ cl 4.3–5.9 mm, 2 ov. ♀ 5.5 and 5.7 mm ( OUMNH.ZC 2013-07-016) China, Guangdong Province, swampy area near Conghua City, 23.57495°N 113.43740°E, coll. W. + M. Klotz 0 1.04.2012.

Description. Cephalothorax and cephalic appendages. Rostrum ( Fig. 1 A, B), straight, slightly directed downwards, tip straight or slightly directed upwards, reaching to end of basal segment of antennular peduncle in smaller specimens or to half of second segments in large specimens, 0.30–0.48 (median 0.37) times as long as carapace, rostrum formula 3–7 (4–5) + 7–15 / 0–6 (1–4). Inferior orbital angle nearly fused with an antennal spine. Pterygostomial angle subrectangular, slightly produced forward. Eyes well developed with globular cornea. Antennular peduncle 0.49–0.63 (median 0.53) times as long as carapace, first segment 2.10–2.64 (median 2.25) times as long as second segment, second segment 1.52–2.14 (median 1.93) times longer than third segment. Stylocerite reaching to 0.40–0.50 times of second segment of antennular peduncle. Scaphocerite ( Fig. 1 G) 2.51–2.96 (median 2.80) times as long as wide.

Abdominal somites, telson and uropods. Sixth abdominal somite 0.44–0.56 (median 0.47) times carapace length, 1.52–1.65 (median 1.59) times as long as fifth somite, 0.79–0.99 (median 0.82) times as long as telson. Telson ( Fig. 1 C, D) length 2.68–2.89 (median 2.82) times as long as proximal wide, distal margin convex with a median projection, with 4–5 pairs of short spiniform setae dorsal and one pair of short spiniform setae dorsolateral; distal end with 6–8 strong spiniform setae, lateral pair distinctly longer than others, sublateral pair shorter than lateral and next pair, innermost pair shortest. Preanal carina ( Fig. 1 E) low, rounded, lacking a spine, with few setae. Uropodal diaeresis ( Fig. 1 F) with 17–22 movable spiniform setae, outermost ones slightly shorter than lateral angle.

Mouthparts and branchiae. Incisor process of mandible ( Fig. 1 H) ending in irregular teeth, molar process truncated. Lower lacinia of maxillula ( Fig. 1 I) 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. 1 J) subdivided, palp slender, scaphognathite tapering posteriorly, fringed with long, curved setae at posterior margin. Palp of first maxilliped ( Fig. 1 K, L) ending in a blunt triangular extension. Podobranch on second maxilliped ( Fig. 1 M) well developed. Third maxilliped ( Fig. 1 N) with two arthrobranches. 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. 2 A, C); chela of first pereiopod 1.76–2.24 (median 2.05) times as long as wide, 1.43–1.49 (median 1.45) times length of carpus; tips of fingers ( Fig. 2 B) rounded, with distinct hook in adult specimens; dactylus slightly sexual dimorphic 0,77–1.25 (median 0.97) times as long as palm, 1.00–1,25 (median 1.16) times as long as propodus in males vs. 0.77–0.94 times as long as propodus in females; carpus deeply excavated distally, 1.11–1.46 (median 1.30) times as long as wide, 0.93–0.99 (median 0.96) times length of merus. Merus 2.23–2.83 (median 2.36) times as long as wide, longer than ischium. Chela of second pereiopod 2.43–2.84 (median 2.60) times as long as wide, 1.01–1.08 (median 1.04) times length of carpus; tips of fingers rounded, without hooks, dactylus 1.44–1.62 (median 1.55) times as long as palm; carpus 3.92–5.10 (median 4.50) times as long as wide, 1.01–1.08 (median 1.06) times as long as merus; merus 4.57–5.58 (median 4.84) times as long as wide, longer than ischium. Third pereiopod ( Fig. 2 D, E) slender, not sexually dimorphic, dactylus 2.67–3.10 (median 2.82) times as long as wide (terminal claw and spines on flexor margin included), terminating in one large claw with 4 or 5 accessory spiniform setae on flexor margin; propodus 8.72–11.68 (median 9.36) times as long as wide, 3.50–4.43 (median 3.81) times as long as dactylus; carpus 4.18–5.78 (median 4.57) times as long as wide, 0.71–0.76 (median 0.73) times as long as propodus, 0.52–0.60 (median 0.56) times as long as merus; merus 4.73–5.91 (median 5.69) times as long as wide, 1.67–1.94 (median 1.79) times as long as carpus, bearing 3–5 strong spiniform setae on posterior margin of outer surface. Ischium with 1 spiniform seta. Fifth pereiopod ( Fig. 2 F, G) slender, dactylus 2.56–3.22 (median 2.85) times as long as wide (terminal claw and spiniform setae on flexor margin included), terminating in one large claw with 19–38 spinuliform setae on flexor margin; propodus 10.53–15.65 (median 11.79) times as long as wide, 4.29–5.31 (median 4.73) times length of dactylus, carpus 4.28–5.44 (median 4.50) times as long as wide, 0.53–0.56 (median 0.54) times as long as propodus, 0.68–0.70 (median 0.70) times as long as merus; merus 4.78–7.03 (median 5.18) times as long as wide, 1.43–1.46 (median 1.44) times length of carpus, bearing 2–4 strong spiniform setae on posterior margin of outer surface. Ischium without a strong spiniform seta.

Pleopods. Endopod of male first pleopod ( Fig. 3 A, B) subrectangular, anterior region bent backwards, inner margin concave, distal part not dilated, 2.49–2.71(median 2.52) times as long as proximal width, 0.51–0.58 (median 0.53) times as long as exopod, with appendix interna arising near and reaching slightly beyond distal margin of endopod. Appendix masculina on male second pleopod ( Fig. 3 C) saccate, 4.19–4.54 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 0.8 of appendix masculina.

Size. Postorbital carapace length 3.6–6.8 mm.

Coloration. As shown in colour plate 1A and 3B; posterior part of carapace, 3rd, 4th and 6th abdominal segments dark brown or blackish, some weak whitish blotches on carapace behind eyes, on 1st, 2nd 5th and posterior part of 6th abdominal segment and round white markings on distal part of uropods. Anterior part of cephalothorax, telson and uropods brownish.

Reproductive biology and larval development. Ovigerous females with few eggs; size of undeveloped eggs (without eyespots) 1.03–1.18 x 0.69–0.76 mm, size of developed eggs (containing embryos with eyes) 1.20–1.23 x 0.78–0.89 mm.

From hatching the larvae are able to use the pleopods for swimming, in the laboratory they usually stood on the bottom of the container or the piece of Catappa leaf and walked using the pereiopods. Well-developed uropods appeared in the second larval stage. In this stage most of the appendages (but not the sexual appendages) resemble that of adults in shape and function. Setae only, especially those on the dorsal margin of the telson, on the flexor margin of dactyli of walking legs and numbers of teeth on the rostrum, are increasing in number during further development. Thus the second larval stage was considered as juvenile. Morphology of the first larval stage with well-developed and functional pereiopods and chelipeds as well as the shape and spinulation of the telson and reduction to one larval stage are typical for species with direct larval development (DD) ( Benzie & Silva 1983; Dudgeon 1987; Lai & Shy 2009). Weak conical teeth-like protuberances instead of developed setae on tips of fingers of chelipeds, maxillipeds and maxillae may suggest that larvae of this instar do not feed and thus may be classified as lecithotrophic ( Anger 2001). The morphology of the 1st larval stage is described in detail and only the changes observed in the following stage are presented below.

Stage I, decapodit ( Figs. 4 , 5 )

Total length: 3.2–3.8 mm, (n = 5); carapace length: 0.96–0.98 mm (n = 5). Total length approximate due to the convexity of preserved specimens.

Duration of stage: 3–5 days.

Rostrum ( Fig. 4 A, B) short, not exceeding distal margin of 1st antennular peduncle, without teeth on dorsal and ventral margin, with two fine simple setae near tip.

Carapace ( Fig. 4 A) without antennal or other spines.

Eyes sessile.

Abdomen ( Fig. 4 A) with 6 somites, last somite incompletely separated from telson.

Telson ( Fig. 4 A, C) spatulate with a distinct notch on posterior margin, with 8 pairs of plumose setae, innermost small, outermost feathered on posterior margin only. Uropods absent.

Antennule ( Fig. 4 D) with peduncle 3-segmented; stylocerite reaching to about midlength of first segment of antennular peduncle, rounded, narrowing distally to an acute tip, with 3 simple setae lateral; first segment of peduncle with 2 or 3 small plumose setae lateral, one large plumose seta distolateral, 1 or 2 spiniform setae and about 8 fine simple setae distal; second segment with 3 large plumose setae lateral, 3 or 4 spiniform setae and about 8 simple setae distal; third antennular peduncle with 5–7 large plumose setae lateral to ventral; inner flagellum with 6 segments, 3rd segment ( Fig. 4 E) with 3 club-like aesthetascs; outer flagellum with 7 segments.

Antennae ( Fig. 4 F) with scaphocerite well developed, unsegmented distally, with a large, acute teeth on distolateral margin and 21–23 plumose setae; flagellum with 46–51 segments.

Mandibles ( Fig. 4 G) asymmetric, with molar processes well developed, truncated; incisor processes with few irregular teeth, a ridge with 5–7 fine simple setae and 2–3 additional sigmoid setae in gap between this ridge and the incisor process.

Maxillule ( Fig. 4 H) with coxal endite rounded, bearing about 18–20 blunt protuberances on margin, 8 teethlike protuberances submarginal; basal endite with two rows of 6–7 and 10–11 blunt protuberances; endopod palplike with a tooth near tip.

Maxillae ( Fig. 4 I) with coxal endite bearing 30–40 simple setae; basal endite with 4–6 conical teeth-like protuberances on folded distal lobe, with about 10 on proximal lobe; endopod palp-like, unarmed; about 41 plumose setae on distal and lateral margin of scaphognatite, posterior directed lobe with 3 large and one smaller setae distally.

First maxilliped ( Fig. 4 J) Coxa with up to 5 plumose setae; basis with 20–25 conical teeth-like protuberances, endopod ending in a stout fingerlike projection with 1 or 2 plumose setae; exopod with about 18 plumose setae on lateral margin, no setae on distal, palp-like tip.

Second maxilliped ( Fig. 4 K) with coxa bearing one seta and a podobranch reduced to as small lamina; basis with 10 simple setae; endopod 3-segmented, 3 or 4 conical teeth-like protuberances at outer edge of angle of last segment, two rows of about 12–15 conical teeth-like protuberances on medially directed face; exopod unsegmented with 4 large plumose setae terminal and 2 smaller ones subterminal.

Third maxilliped ( Fig. 5 A) Coxa with epipod well developed, bilobed, posterior directed lobe with a terminal hook; endopod 3-segmented, proximal segment with one strong spiniform seate distally and 6 or 7 simple setae on mesial margin; median segment with two spiniform setae and 4 simple setae distally and 2 or 3 spiniform setae mesially, distal segment with a strong spine terminal and 3 subterminal spiniform setae, 4 rows with 3, 3–4, 4, 3–4 short but strong serrate setae and one spiniform seta near 3rd row of serrate setae, upper margin with few simple setae; exopod unsegmented with 4 large plumose setae terminal and 2 smaller ones subterminal.

First cheliped ( Fig. 5 B) chelate; coxa with a well developed epipod and one setobranch; carpus short, distinctly excavated distally; tips of fingers of chelae lacking brushes of setae typical for adults but with numerous conical teeth-like protuberances, dactylus slightly longer than propodus.

Second cheliped ( Fig. 5 C) chelate; coxa with a well developed epipod and one setobranch; carpus more slender than carpus of first cheliped, slightly excavated distally; tips of fingers lacking brushes of setae typical for adults but with numerous conical teeth-like protuberances, dactylus slightly longer than propodus.

Third pereiopod ( Fig. 5 D) well developed; coxa with a well developed epipod and one setobranch; ischium with one spiniform seta; merus with 3 spiniform setae; carpus with 1 large spiniform seta lateral and a smaller one subdistal; propodus with 2 spiniform setae distal and 3–5 (mostly 4) pairs of spiniform setae on median edge, dactylus terminating in one claw with 2 subterminal spiniform setae.

Fourth pereiopod ( Fig. 5 E) well developed; coxa lacking an epipod but with one setobranch; ischium with one spiniform seta; merus with 3 spiniform setae; carpus with 1 large spiniform seta lateral and a smaller one subdistal; propodus with 2 spiniform setae distal and 3–4 (mostly 4) pairs of spiniform setae on median edge, dactylus terminating in one claw with 2 subterminal spiniform setae.

Fifth pereiopod ( Fig. 5 F) well developed; coxa lacking an epipod or setobranch; ischium without spiniform seta; merus with 2 spiniform setae; carpus with 1 large spiniform seta lateral and a smaller one subdistal; propodus with 2 spiniform setae distal and 3–4 (mostly 4) pairs of spiniform setae on median edge, dactylus terminating in one claw with 4–5 subterminal spiniform setae.

First pleopod ( Fig. 5 G) well developed; endopod with 2–3 plumose setae on outer margin, without an appendix interna; exopod with 11–13 plumose setae; basis with 1 simple seta distal.

Second pleopod ( Fig. 5 H) well developed, endopod with 7 or 8 plumose setae and one simple setae subterminal, one seta near base of endopod, appendix interna with 4–5 hook-like spinules; exopod with 11 or 12 plumose setae and one simple seta subterminal; basis with one simple seta.

Third to fifth pleopod ( Fig. 5 I) well developed, endopods with 7–9 plumose setae and 1 or 2 (mostly 1) plumose setae basal to appendix interna and one simple seta subterminal; appendix interna with 3–5 hook-like spinules distal; exopod with 11 or 12 (mostly 11) plumose setae and one simple seta subterminal; one simple seta on basis.

Stage II, juvenile ( Fig. 6 , 7 )

Total length: 3.6–3.7 mm, (n = 3); carapace length: 1.03–1.04 mm (n = 3). Total length approximate due to the convexity of preserved specimens.

Duration of stage: unknown.

Rostrum ( Fig. 6 A) short, reaching to distal margin of 1st antennular peduncle, with 2 teeth on dorsal, none on ventral margin.

Carapace ( Fig. 6 A) with antennal spine fused with orbital margin.

Eyes sessile.

Abdomen with 6 somites, last somite separated from telson, uropods developed.

Telson ( Fig. 6 B) separated from 6th abdominal segment, spatulate, slightly narrowing distal, distal with a notch, 7 pairs of setae on distal margin, innermost small, inner 6 pairs plumose, outermost simple. One pair of spiniform setae dorsolateral (one side of 1 specimen with 2 dorsolateral spines). Uropods ( Fig. 6 C) developed, endopod with 16 to 20 plumose setae and one fine simple setae subterminal; exopod with 10–22 plumose setae and one or 2 fine simple setae subterminal; diaeresis ( Fig. 6 C, D) with 2– 4 spiniform setae longer than lateral teeth.

Antennule ( Fig. 6 E) with stylocerite acute, remaining appendage as in first stage.

Antennae ( Fig. 6 F) as in stage 1.

Mandibles ( Fig. 6 G) as in stage 1.

Maxillule ( Fig. 6 H) with coxal endite with 20 or 21 setae near margin and 8–11 simple setae submarginal; basal endite with two rows of 8 and 10 teeth and one spiniform setae; endopodite palp-like with one spiniform setae and one simple setae near tip.

Maxillae ( Fig. 6 I) with coxal endite bearing 40–46 simple setae; basal endite with about 10 and some fine setae on distal lobe, with numerous simple setae on proximal lobe.

First maxilliped ( Fig. 6 J) basis with numerous seeate setae; exopod with about 13–16 plumose setae on lateral margin, 3 or 4 feathered setae on distal, palp-like tip.

Second maxilliped ( Fig. 6 K) with 6 feathered setae at outer edge of angle of ultimate segment of endopod, about 30 simple setae on medially directed face of this segment.

Third maxilliped ( Fig. 7 A) with 3 or 4 spiniform setae mesially of distal segment of endopod.

First cheliped ( Fig. 7 B) with tips of fingers bearing brushes of setae typical for adults. Second cheliped ( Fig. 7 C) with tips of fingers bearing brushes of setae typical for adults. Third pereiopod ( Fig. 7 D) as in stage 1.

Fourth pereiopod ( Fig.7 E) as in stage 1.

Fifth pereiopod ( Fig. 7 F) as in stage 1.

First pleopod ( Fig. 7 G) as in stage 1.

Second pleopod ( Fig. 7 H) as in stage 1.

Third to fifth pleopod ( Fig. 7 I) as in stage 1.

Etymology. Caridina logemanni n. sp. is named after Carsten and Frank Logemann, for their long lasting work on bee shrimp as aquarium pets and their support of our research in Hong Kong.

Remarks. Caridina logemanni n. sp. is close to C. cantonensis Yu, 1938 with its rostrum reaching to about midlength of second segment of antennular peduncle in fully grown specimens and anterior region of endopod of male first pleopods bent backwards. Beside its peculiar life coloration, which allows to distinguish these two species in the field, C. logemanni n. sp. differs from C. cantonensis in shape and proportions of the carpus of first pereiopod viz. carpus deeply excavated distally, 1.11–1.46 times as long as wide vs. moderately excavated distally, 1.41–1.9 times as long as wide in C. cantonensis . The dactylus of fifth pereiopod is shorter (0.19–0.23 times as long as propodus vs. 0.23–0.30 times as long in C. cantonensis ) and armed with fewer spiniform setae on fexor margin (19–38 vs. 38–45 in C. cantonensis ) and the endopod of male first pleopod is slender (2.44–2.71 times as long as wide vs. 2.13–2.35 times in C. cantonensis ). Some differences could also be found in the shape and spinulation of the distal margin of telson. This margin appears convex with lateral pair distinctly longer than others in C. logemanni n. sp. vs. strong convex to triangular with lateral pair slightly longer than sublateral pair but comparable in length to inner pairs in C. cantonensis . Numbers of spines on distal margin of telson 6 to 8 in C. logemanni n. sp. vs. 8 to 10 in C. cantonensis . In the present study, the larval morphology and development of C. logemanni was found to be similar to that of C. cantonensis collected from a mountain stream in an area nearby the type locality of C. logemanni n. sp. Both species exhibit a typical direct development type. The first larval stage of C. logemanni n. sp. differs from C. cantonensis in development of the antennule (inner flagellum with 6 segments vs. with 5 segments in C. cantonensis ), antenna (scaphocerite with 21–23 (mostly 22) plumose setae (vs. 18–20 setae in C. cantonensis ), flagellum with 46–51 segments (vs. 39–41 in C. cantonensis ), second maxilliped (basis with about 10 simple setae (vs. with 5 blunt teeth-like protuberances in C. cantonensis ), carpus of first cheliped deeply excavated distally (vs. moderately excavated in C. cantonensis ) and propodi of third and fourth pereiopods (with 3–5 spiniform setae mesially (vs. with 2 spiniform setae in C. cantonensis ). In all of these characters larvae of C. logemanni are more “adult-like” compared to C. cantonensis . In 1987 D. Dudgeon described the larval development of Neocaridina serrata from the Lam Tsuen River in Hong Kong ( Dudgeon 1987). Subsequently this species was considered as being C. cantonensis ( Cai & Ng 1999) . For the time being it is not clear whether the differences in larval development of C. cantonensis between populations form the Lam Tsuen River (abbreviated larval development with one zoeal stage) and from NE New Territories (direct development, this study) are caused by differences in study design (based on larvae collected from natural habitat vs. based on laboratory reared material), or whether the sample of larvae used in the study of Dudgeon contained more than one species.

Caridina logemanni n. sp. is also similar to C. trifasciata Yam & Cai, 2003 described from the New Territories, Hong Kong, a species also known for its peculiar banded life coloration but differing from this species by the natural shape of the endopod of the male first pleopod, which is folded backwards in the anterior region of endopod vs. unfolded in C. trifasciata . The appendix masculina on the second pleopods of males are more stout in C. logemanni (3.96–4.54, median 4.31 times as long as wide, 0.55–0.60, median 0.57 times as long as endopod vs. 5.50–6.17, median 5.80 times as long as wide, 0.62–0.67 median 0.65 times as long as endopod in C. trifasciata ). Lateral pair of spines on distal margin of telson appears distinctly longer than others in C. logemanni n. sp. vs. lateral pair slightly longer than sublateral pair but comparable in length to inner pairs in C. trifasciata . Dactyli of 3rd and 4th pereiopods are somewhat stouter in C. logemanni n. sp. (length to breadth ratio 2.57–3.15, median 2.90 and 2.52–3.10 median 2.78 vs. 3.17–3.55, median 3.46 and 3.08–3.60, median 3.43 in C. trifasciata ).

Distribution and habitat. Caridina logemanni n. sp. is known from three small hill streams in the northeastern part of the New Territories, Hong Kong. No other shrimp have been found in these three streams despite the occurrence of dense populations of Caridina cantonensis in neighboring streams. The shrimp are living in deposits of dead leaves and between boulders in shallow water. The following water parameters have been recorded in the habitat: pH 6.0; conductivity 33 µS; dissolved oxygen 8.1 mg /l; 19.8 °C.

Figures

FIGURE 1. Caridina logemanni n. sp., paratype male, cl 5.6 mm, ZMB 28222; Präp. 5043 – 5046 (A) Cephalothorax and cephalic appendages; (B) rostrum; (C) telson; (D) distal end of telson; (E) preanal carina; (F) uropodal diaeresis; (G) scaphocerite; (H) mandible; (I) maxillule; (J) maxilla; (K) first maxilliped; (L) palp of first maxilliped (M) second maxilliped; (N) third maxilliped.

FIGURE 2. Caridina logemanni n. sp., paratype male, cl 5.6 mm, ZMB 28222; Präp. 5043 – 5046 (A) first pereiopod, (B) dactyli of first cheliped, setae partially omitted; (C) second pereiopod; (D) third pereiopod; (E) dactylus of third pereiopod; (F) fifth pereiopod; (G) dactylus of fifth pereiopod.

FIGURE 3. Caridina logemanni n. sp., paratype male, cl 5.6 mm, ZMB 28222; Präp. 5043 – 5046 (A) endopod of male first pleopod (flattened), (B) endopod of male first pleopod (posterior view in natural shape); (C) appendix masculina on male second pleopod.

FIGURE 4. Caridina logemanni n. sp., larval stage I (decapodid) (A) general view, lateral; (B) rostrum; (C) telson; (D) antennule; (E) aesthetascs on inner flagellum of antennule; (F antenna with scaphocerite; (G) mandible; (H) maxillule; (I) maxilla; (J) first maxilliped; (K) second maxilliped.

FIGURE 5. Caridina logemanni n. sp., larval stage I (decapodid) (A) third maxilliped; (B) first pereiopod; (C) second pereiopod; (D) third pereiopod; (E) fourth pereiopod; (F) fifth pereiopod; (G) first pleopod; (H) second pleopod; (I) fifth pleopod.

FIGURE 6. Caridina logemanni n. sp., larval stage II (juvenile) (A) rostrum; (B) telson; (C) uropods; (D) uropodal diaeresis; (E) antennule; (F) antenna with scaphocerite; (G) mandible; (H) maxillule; (I) maxilla; (J) first maxilliped; (K) second maxilliped.

FIGURE 7. Caridina logemanni n. sp., larval stage II (juvenile) (A) third maxilliped; (B) first pereiopod; (C) second pereiopod; (D) third pereiopod; (E) fourth pereiopod; (F) fifth pereiopod; (G) first pleopod; (H) second pleopod; (I) fifth pleopod.