taxonID	type	description	language	source
9F18B6F6A3555E5FB48868BB80DC570C.taxon	description	Figs 2, 3, 4	en	Do, Van Tu, Phan, Thi Yen, von Rintelen, Kristina, Le, Hung Anh, von Rintelen, Thomas (2025): Descriptions of four new species of atyid shrimp (Crustacea, Decapoda, Atyidae) in Vietnam. ZooKeys 1247: 151-186, DOI: 10.3897/zookeys.1247.148607, URL: https://zookeys.pensoft.net/article/148607/download/xml/
9F18B6F6A3555E5FB48868BB80DC570C.taxon	diagnosis	Diagnosis. Caridina ngocson sp. nov. can be distinguished from other members of the genus Caridina by a combination of the following characteristics: short, slender, and slightly downward-curving rostrum, reaching from beginning to middle of second segment of antennular peduncle (Fig. 2 A); stylocerite extending beyond distal end of basal antennular peduncle; rostral formula of 4 – 6 + 5 – 11 / 0 – 2; well-developed eyes (Fig. 2 B); kidney-shaped endopod of male first pleopod, with appendix interna slightly exceeding terminal margin of endopod by 0.23 of its length (Fig. 3 G, H); appendix masculina of male second pleopod slender, reaching approximately 0.43 × endopod length; appendix interna extending ~ 0.60 × length of appendix masculina (Fig. 3 I, J); and large eggs.	en	Do, Van Tu, Phan, Thi Yen, von Rintelen, Kristina, Le, Hung Anh, von Rintelen, Thomas (2025): Descriptions of four new species of atyid shrimp (Crustacea, Decapoda, Atyidae) in Vietnam. ZooKeys 1247: 151-186, DOI: 10.3897/zookeys.1247.148607, URL: https://zookeys.pensoft.net/article/148607/download/xml/
9F18B6F6A3555E5FB48868BB80DC570C.taxon	description	Description. Cephalothorax and cephalic appendages. Carapace length 3.8 – 5.3 mm (median 4.4 mm, n = 12). Rostrum short and slender, straight, reaching to beginning to middle of second segment of antennular peduncle, 0.25 – 0.4 (median 0.33) × as long as carapace, rostral formula 4 – 6 + 5 – 11 / 0 – 2 (Fig. 2 A). Suborbital angle acute, completely fused with antennal spine; pterygostomian margin rounded, slightly introduced forward (Fig. 2 A). Eyes well developed with globular cornea, anterior end reaching to 0.8 × length of basal segment of antennular peduncle (Fig. 2 A). Antennular peduncle 0.47 – 0.58 (median 0.54) × as long as carapace; basal segment 1.98 – 2.39 (median 2.05) × as long as second segment, second segment 0.96 – 1.24 (median 1.05) × as long as third segment (Fig. 2 B). Stylocerite reaching to beginning or to 0.4 × length of second segment of antennular peduncle (Fig. 2 B). Scaphocerite ovate, reaching beyond distal end of antennular peduncle, 2.55 – 2.97 (median 2.55) × as long as wide (Fig. 2 A, C). Abdominal somites, telson, and uropods. Sixth abdominal somite 0.36 – 0.4 (median 0.38) × length of carapace, 1.36 – 1.69 (median 1.45) × as long as fifth abdominal somite, 0.64 – 0.84 (median 0.73) × length of telson. Telson length 2.14 – 2.55 (median 2.27) × as long as proximal wide, distal margin triangular, terminating in a short median projection, with 4 – 6 pairs of dorsal spiniform setae and one pair of dorso-subdistal spiniform setae; distal end with three or four pairs of spiniform setae, lateral pair longer than intermediate pairs (Fig. 2 D, E). Preanal carina low, slightly bent backwards, with few setae, lacking a spine (Fig. 2 F). Uropodal diaeresis with 16 – 21 (median 20) movable spiniform setae, outermost longer than lateral angle (Fig. 2 G). Mouthparts and branchiae. Incisor process of mandible ending in one row of 5 – 7 irregular teeth, molar process truncated (Fig. 2 H). Lower lacinia of maxillula broadly rounded, upper lacinia elongated, with several distinct teeth and setae on inner margin, palp stout with few simple setae at tip (Fig. 2 I). Upper endites of maxilla subdivided, palp short, scaphognathite tapering posteriorly, with numerous long, curved setae at posterior margin (Fig. 2 J). Distal end of palp of first maxilliped triangular, with a short projection; flagellum of the exopod very elongated, endopod high, reaching 0.8 × length of flagellum of exopod (Fig. 2 K, L). Podobranch of second maxilliped slightly reduced, with few finger-like projections (Fig. 2 M). Third maxilliped reaching to end of antennular peduncle, ending in single terminal claw, exopod reaching 0.6 × length of penultimate segment; ultimate segment longer than penultimate segment; epipod present on the coxa (Fig. 2 N). Branchial formula as typical for genus Paracaridina Liang, Guo & Tang, 1999, five pairs of pleurobranchs well developed; two pairs of arthrobranchs on third maxillipeds, with second pair strongly reduced in size; one pair of podobranchs on second maxilliped slightly reduced, arthrobranch on first pereiopod absent (Liang et al. 1999). Pereiopods. Epipods present on first fourth pereiopods. First pereiopod short, robust, reaching end of basal segment of antennular peduncle; chela 1.91 – 2.22 (median 2.02) × as long as wide, 1.22 – 1.44 (median 1.26) × length of carpus; tips of fingers rounded, without hook; dactylus 0.73 – 0.89 (median 0.83) × as long as palm; carpus excavated strongly anteriorly, 1.73 – 2.25 (median 1.89) × as long as wide; carpus 0.83 – 1.01 (median 0.95) × length of merus; merus 2.3 – 2.94 (median 2.67) × as long as wide, longer than ischium (Fig. 3 A). Second pereiopod long, slender, reaching beyond distal end of antennular peduncle; chela 2.19 – 2.62 (median 2.4) × as long as wide, 0.60 – 0.78 (median 0.69) × length of carpus; tips of fingers rounded, without hook; dactylus 1.04 – 1.4 (median 1.17) × as long as palm; carpus 5.0 – 5.69 (median 5.16) × as long as wide, 0.93 – 1.05 (median 1.0) × as long as merus; merus 4.81 – 5.58 (median 5.12) × as long as wide, longer than ischium (Fig. 3 B). Third pereiopod slender, reaching beyond distal end of antennular peduncle by its dactylus, terminating in one claw, with five accessory spiniform setae on flexor margin, dactylus 2.44 – 3.19 (median 2.82) × as long as wide (terminal claw and spiniform setae on flexor margin included), propodus 8.38 – 9.3 (median 8.79) × as long as wide, 4 – 4.64 (median 4.17) × as long as dactylus; carpus 3.41 – 4.41 (median 4.01) × as long as wide, 0.53 – 0.69 (median 0.62) × as long as propodus, 0.46 – 0.55 (median 0.52) × as long as merus; merus 5.33 – 6.68 (median 5.74) × as long as wide, bearing 3 strong, movable spiniform setae on posterior margin of outer surface; ischium with one small movable spiniform seta (Fig. 3 C, D). Fifth pereiopod slender, reaching to end of third segment of antennular peduncle, dactylus 3.27 – 3.67 (median 3.53) × as long as wide (terminal claw and spiniform setae on flexor margin included), terminating in one large claw, with 30 – 37 spiniform setae on flexor margin; propodus 9.82 – 12.06 (median 10.55) × as long as wide, 3.06 – 3.98 (median 3.54) × length of dactylus; carpus 3.45 – 4.39 (median 4.0) × as long as wide, 0.46 – 0.57 (median 0.48) × as long as propodus, 0.56 – 0.66 (median 0.61) × as long as merus; merus 5.4 – 6.21 (median 5.99) × as long as wide, bearing 3 strong, movable spiniform setae on posterior margin of outer surface, ischium without movable spiniform setae (Fig. 3 E, F). Pleopods. Endopod of male first pleopod extending to 0.62 × exopod, elongated and kidney-shaped, 2.43 – 3.04 (median 2.91) × as long as proximal width, inner margin concave, outer margin slightly convex, rounded distally, long pappose setae on outer and distal margins, medium-length setae on inner margin; with appendix interna curved upwards, exceeding terminal margin of endopod by 0.51 its length (Fig. 3 G, H). Appendix masculina of male second pleopod slender, reaching to proximal 0.62 × endopod length, 7.38 × as long as distal width, stick-shaped, with some short spiniform setae on outer surface and some long spiniform setae on distal surface; appendix interna at the middle of appendix masculina, narrow, small, extending ~ 0.54 × length of appendix masculina (Fig. 3 I, J).	en	Do, Van Tu, Phan, Thi Yen, von Rintelen, Kristina, Le, Hung Anh, von Rintelen, Thomas (2025): Descriptions of four new species of atyid shrimp (Crustacea, Decapoda, Atyidae) in Vietnam. ZooKeys 1247: 151-186, DOI: 10.3897/zookeys.1247.148607, URL: https://zookeys.pensoft.net/article/148607/download/xml/
9F18B6F6A3555E5FB48868BB80DC570C.taxon	etymology	Etymology. The new species is named after the type locality, Ngoc Son Commune. The name is used as a noun in apposition.	en	Do, Van Tu, Phan, Thi Yen, von Rintelen, Kristina, Le, Hung Anh, von Rintelen, Thomas (2025): Descriptions of four new species of atyid shrimp (Crustacea, Decapoda, Atyidae) in Vietnam. ZooKeys 1247: 151-186, DOI: 10.3897/zookeys.1247.148607, URL: https://zookeys.pensoft.net/article/148607/download/xml/
9F18B6F6A3555E5FB48868BB80DC570C.taxon	distribution	Distribution. Our unpublished survey data throughout Vietnam indicate that this species is restricted to the Ngoc Son district of Hoa Binh province. The estimated area of occupancy is less than 500 km 2. The altitude of the habitat area ranges from 200 to 700 m. The large eggs are also clearly indicative of a landlocked life cycle.	en	Do, Van Tu, Phan, Thi Yen, von Rintelen, Kristina, Le, Hung Anh, von Rintelen, Thomas (2025): Descriptions of four new species of atyid shrimp (Crustacea, Decapoda, Atyidae) in Vietnam. ZooKeys 1247: 151-186, DOI: 10.3897/zookeys.1247.148607, URL: https://zookeys.pensoft.net/article/148607/download/xml/
0EBC4DD566205EF681C05C4E0995CC2C.taxon	description	Figs 14, 15, 16, 17	en	Do, Van Tu, Phan, Thi Yen, von Rintelen, Kristina, Le, Hung Anh, von Rintelen, Thomas (2025): Descriptions of four new species of atyid shrimp (Crustacea, Decapoda, Atyidae) in Vietnam. ZooKeys 1247: 151-186, DOI: 10.3897/zookeys.1247.148607, URL: https://zookeys.pensoft.net/article/148607/download/xml/
0EBC4DD566205EF681C05C4E0995CC2C.taxon	diagnosis	Diagnosis. This new species is characterized by several morphological characters such as short and slender rostrum, reaching just to the end of the basal segment of antennular peduncle or sometimes to the middle of second segment, without or with a few small teeth (Fig. 14 A); medium stylocerite, reaching to the end of the basal segment or sometimes to beginning of second segment of the antennular peduncle (Fig. 14 B); dactylus of the first pereiopod is shorter than palm (Fig. 15 A); long, sub-rectangular endopod of the male first pleopod, extending to 0.87 of the length of the exopod, with short appendix interna, not or slightly exceeding the terminal margin of the endopod (Fig. 15 G, H); short and stick-shaped appendix masculina of male second pleopod, reaching to proximal 0.8 of the length of the endopod, with narrow and small appendix interna, extending ~ 0.6 of the length of appendix masculina (Fig. 15 I, J).	en	Do, Van Tu, Phan, Thi Yen, von Rintelen, Kristina, Le, Hung Anh, von Rintelen, Thomas (2025): Descriptions of four new species of atyid shrimp (Crustacea, Decapoda, Atyidae) in Vietnam. ZooKeys 1247: 151-186, DOI: 10.3897/zookeys.1247.148607, URL: https://zookeys.pensoft.net/article/148607/download/xml/
0EBC4DD566205EF681C05C4E0995CC2C.taxon	description	Description. Cephalothorax and cephalic appendages. Carapace length 3.8 – 5.8 mm (median 4.6 mm, n = 20). Rostrum very short and slender, straight, mostly reaching near the end of basal segment of antennular peduncle, sometimes to middle of second segment, 0.1 – 0.2 (median 0.2) as long as carapace, teeth small, rostral formula 0 – 4 + 0 – 8 / 0 – 2 (Fig. 14 A). Suborbital angle acute, completely fused with antennal spine; pterygostomian margin rounded, slightly produced forward (Fig. 14 A). Eyes normally developed with globular cornea, eyestalk short, anterior end reaching to 0.6 of length of basal segment of antennular peduncle (Fig. 14 A). Antennular peduncle 0.37 – 0.44 (median 0.43) × as long as carapace; basal segment 1.6 – 2.2 (median 1.67) × as long as second segment, second segment 1.2 – 1.25 (median 1.25) × as long as third segment (Fig. 14 B). Stylocerite reaching to end of basal segment or sometime to beginning of second segment of antennular peduncle (Fig. 14 A, B). Scaphocerite ovate, reaching beyond distal end of antennular peduncle, 2.33 – 2.67 (median 2.5) × as long as wide (Fig. 14 A, C). Abdominal somites, telson, and uropods. Sixth abdominal somite 0.3 – 0.42 (median 0.38) × length of carapace, 1.31 – 1.64 (median 1.42) × as long as fifth abdominal somite, 0.76 – 1.0 (median 0.89) × length of telson. Telson length 2.1 – 2.38 (median 2.25) × as long as proximal wide, distal margin triangular, terminating in a short median projection, with six pairs of dorsal spiniform setae and one pair of dorso-subdistal spiniform setae; distal end with three or four pairs of spiniform setae, lateral pair slightly shorter than intermediate pairs (Fig. 14 D, E). Preanal carina moderately high, slightly bent backwards, with few setae, lacking a spine (Fig. 14 F). Uropodal diaeresis with 17 – 20 (median 18) movable spiniform setae, outermost longer than lateral angle (Fig. 14 G). Mouthparts and branchiae. Incisor process of mandible ending in one row of six or seven irregular teeth, molar process truncated (Fig. 14 H). Lower lacinia of maxillula broadly rounded, upper lacinia elongated, with several distinct teeth and setae on inner margin, palp stout with few simple setae at tip (Fig. 14 I). Upper endites of maxilla subdivided, palp short, scaphognathite tapering posteriorly, with numerous long, curved setae at posterior margin (Fig. 14 J). Distal end of palp of first maxilliped triangular, with a short projection; flagellum of the exopod very elongated, endopod high, reaching 0.9 of length of flagellum of exopod (Fig. 14 K, L). Podobranch of second maxilliped slightly reduced, with few finger-like projections (Fig. 14 M). Third maxilliped reaching near the end of antennular peduncle, ending in single terminal claw, exopod reaching 0.4 of length of penultimate segment; ultimate segment shorter penultimate segment; epipod present on the coxa (Fig. 14 N). Branchial formula as is typical for genus, five pairs of pleurobranchs well developed; three pairs of arthrobranchs, two on third maxillipeds, with second pair strongly reduced in size, one pair on first pereiopod; one pair of podobranchs on second maxillipeds slightly reduced. Pereiopods. Epipods present on first to fourth pereiopods. First pereiopod short, robust, reaching beyond end of basal segment of antennular peduncle; chela 2.03 – 2.35 (median 2.11) × as long as wide, 1.37 – 1.5 (median 1.4) × length of carpus; tips of fingers rounded, with hook; dactylus shorter than palm, 0.82 – 0.9 (median 0.88) × as long as palm; carpus excavated strongly anteriorly, 1.5 – 1.75 (median 1.65) × as long as wide; carpus 0.8 – 1.0 (median 0.9) × length of merus; merus 2.39 – 2.67 (median 2.47) × as long as wide, longer than ischium (Fig. 15 A). Second pereiopod long, slender, reaching to distal end of antennular peduncle; chela 3.16 – 3.5 (median 3.28) × as long as wide, 0.64 – 0.71 (median 0.67) × length of carpus; tips of fingers rounded, without hook; dactylus 1.33 – 1.64 (median 1.52) × as long as palm; carpus 6.07 – 7.08 (median 6.57) × as long as wide, 1.02 – 1.12 (median 1.11) × as long as merus; merus 5.92 – 6.38 (median 6.33) × as long as wide, longer than ischium (Fig. 15 B). Third pereiopod slender, reaching beyond end of scaphocerite by its dactylus, terminating in one claw, with four or five accessory spiniform setae on flexor margin, dactylus 3.0 – 3.83 (median 3.64) × as long as wide (terminal claw and spiniform setae on flexor margin included), propodus 8.5 – 9.75 (median 9.0) × as long as wide, 3.48 – 3.950 (median 3.86) × as long as dactylus; carpus 4.69 – 4.83 (median 4.77) × as long as wide, 0.67 – 0.76 (median 0.72) × as long as propodus, 0.52 – 0.58 (median 0.53) × as long as merus; merus 5.63 – 6.59 (median 6.05) × as long as wide, bearing 3 strong, movable spiniform setae on posterior margin of outer surface; ischium without movable spiniform seta (Fig. 15 C, D). Fifth pereiopod slender, reaching to end of second segment of antennular peduncle, dactylus 2.67 – 3.38 (median 3.13) × as long as wide (terminal claw and spiniform setae on flexor margin included), terminating in one large claw, with 37 – 39 spiniform setae on flexor margin; propodus 11.25 – 13.14 (median 11.5) × as long as wide, 3.41 – 3.91 (median 3.75) × length of dactylus; carpus 4.73 – 5.0 (median 5.0) × as long as wide, 0.56 – 0.6 (median 0.58) × as long as propodus, 0.63 – 0.71 (median 0.67) × as long as merus; merus 5.5 – 6.33 (median 6.31) × as long as wide, bearing 3 strong, movable spiniform setae on posterior margin of outer surface, ischium without movable spiniform setae (Fig. 15 E, F). Pleopods. Endopod of male first pleopod extending to 0.87 of exopod, sub-rectangular in shape, anterior part not folded backwards, 3.15 – 3.35 (median 3.19) × as long as proximal width, inner margin concave, outer margin slightly convex, rounded distally, long simple setae on outer and distal margins, medium-length setae on inner margin; with appendix interna curved upwards, not or slightly exceeding terminal margin of endopod by 0.23 of its length (Fig. 15 G, H). Appendix masculina of male second pleopod slender, reaching to proximal 0.8 of endopod length, 7.3 × as long as distal width, stick-shaped, with some spiniform setae on outer surface and on distal surface; appendix interna at the middle of appendix masculina, narrow, small, extending ~ 0.54 length of appendix masculina (Fig. 15 I, J).	en	Do, Van Tu, Phan, Thi Yen, von Rintelen, Kristina, Le, Hung Anh, von Rintelen, Thomas (2025): Descriptions of four new species of atyid shrimp (Crustacea, Decapoda, Atyidae) in Vietnam. ZooKeys 1247: 151-186, DOI: 10.3897/zookeys.1247.148607, URL: https://zookeys.pensoft.net/article/148607/download/xml/
0EBC4DD566205EF681C05C4E0995CC2C.taxon	etymology	Etymology. The new species is named after the type locality, Tam Kim Commune. The name is used as a noun in apposition.	en	Do, Van Tu, Phan, Thi Yen, von Rintelen, Kristina, Le, Hung Anh, von Rintelen, Thomas (2025): Descriptions of four new species of atyid shrimp (Crustacea, Decapoda, Atyidae) in Vietnam. ZooKeys 1247: 151-186, DOI: 10.3897/zookeys.1247.148607, URL: https://zookeys.pensoft.net/article/148607/download/xml/
0EBC4DD566205EF681C05C4E0995CC2C.taxon	distribution	Distribution. This species is only distributed in Nguyen Binh District, Cao Bang Province in the high elevation from 500 m to 800 m. The estimated area of occupancy is less than 1000 km 2.	en	Do, Van Tu, Phan, Thi Yen, von Rintelen, Kristina, Le, Hung Anh, von Rintelen, Thomas (2025): Descriptions of four new species of atyid shrimp (Crustacea, Decapoda, Atyidae) in Vietnam. ZooKeys 1247: 151-186, DOI: 10.3897/zookeys.1247.148607, URL: https://zookeys.pensoft.net/article/148607/download/xml/
EE5C738F20385400A0C0893854EE65A7.taxon	description	Figs 10, 11, 12	en	Do, Van Tu, Phan, Thi Yen, von Rintelen, Kristina, Le, Hung Anh, von Rintelen, Thomas (2025): Descriptions of four new species of atyid shrimp (Crustacea, Decapoda, Atyidae) in Vietnam. ZooKeys 1247: 151-186, DOI: 10.3897/zookeys.1247.148607, URL: https://zookeys.pensoft.net/article/148607/download/xml/
EE5C738F20385400A0C0893854EE65A7.taxon	diagnosis	Diagnosis. This new species is characterized by rostrum short, straight, slender, tapering towards tip, reaching from beginning to end of third segment of antennular peduncle (Fig. 10 A); stylocerite reaches from beginning to 0.2 × length of second segment of the antennular peduncle (Fig. 10 B); carpus of fifth pereiopod slender, 7.3 × as long as wide (Fig. 11 A); endopod of male first pleopod kidney-shaped, extending to 0.52 of exopod, 2.4 × as long as proximal width (Fig. 11 G, H).	en	Do, Van Tu, Phan, Thi Yen, von Rintelen, Kristina, Le, Hung Anh, von Rintelen, Thomas (2025): Descriptions of four new species of atyid shrimp (Crustacea, Decapoda, Atyidae) in Vietnam. ZooKeys 1247: 151-186, DOI: 10.3897/zookeys.1247.148607, URL: https://zookeys.pensoft.net/article/148607/download/xml/
EE5C738F20385400A0C0893854EE65A7.taxon	description	Description. Cephalothorax and cephalic appendages. Carapace length 4.0 – 6.4 mm (median 4.5 mm, n = 11). Rostrum slender, straight, reaching to beginning, sometime to the end of the third segment of antennular peduncle to distal end of antennular peduncle, 0.45 – 0.75 (median 0.52) as long as carapace, rostral formula 4 – 6 + 9 – 14 / 2 – 5 (Fig. 10 A). Suborbital angle acute, completely fused with antennal spine; pterygostomian margin rounded, slightly produced forward (Fig. 10 A). Eyes well developed with globular cornea, anterior end reaching to 0.7 length of basal segment of antennular peduncle (Fig. 10 A). Antennular peduncle 0.46 – 0.67 (median 0.56) as long as carapace; basal segment 1.0 – 1.67 (median 1.25) × as long as second segment, second segment 1.14 – 2 (median 1.58) × as long as third segment (Fig. 10 B). Stylocerite reaching to beginning or to 0.2 of length of second segment of antennular peduncle (Fig. 10 B). Scaphocerite ovate, reaching beyond distal end of antennular peduncle, 3 – 3.81 (median 3.37) × as long as wide (Fig. 10 A, C). Abdominal somites, telson, and uropods. Sixth abdominal somite 0.33 – 0.5 (median 0.4) length of carapace, 1.36 – 1.73 (median 1.5) × as long as fifth abdominal somite, 0.62 – 0.95 (median 0.76) length of telson. Telson length 2.0 – 2.89 (median 2.5) × as long as proximal wide, distal margin triangular, terminating in a short median projection, with 5 – 6 pairs of dorsal spiniform setae and one pair of dorso-subdistal spiniform setae; distal end with 4 – 5 pairs of spiniform setae, lateral pair longer than intermediate pairs (Fig. 10 D, E). Preanal carina low, slightly bent backwards, with few setae, lacking a spine (Fig. 10 F). Uropodal diaeresis with 16 – 21 (median 18) movable spiniform setae, outermost shorter than lateral angle (Fig. 10 G). Mouthparts and branchiae. Incisor process of mandible ending in one row of 6 – 7 irregular teeth, molar process truncated (Fig. 10 H). Lower lacinia of maxillula broadly rounded, upper lacinia elongated, with several distinct teeth and setae on inner margin, palp stout with few simple setae at tip (Fig. 11 I). Upper endites of maxilla subdivided, palp short, scaphognathite tapering posteriorly, with numerous long, curved setae at posterior margin (Fig. 10 J). Distal end of palp of first maxilliped triangular, with a short projection; flagellum of the exopod very elongated, endopod high, reaching 0.8 length of flagellum of exopod (Fig. 10 K, L). Podobranch of second maxilliped slightly reduced, with few finger-like projections (Fig. 10 M). Third maxilliped reaching to end of antennular peduncle, ending in single terminal claw, exopod reaching 0.4 length of penultimate segment; ultimate segment slightly longer than penultimate segment; epipod present on the coxa (Fig. 10 N). Branchial formula as typical for Paracaridina genus, five pairs of pleurobranchs well developed; two pairs of arthrobranchs on third maxillipeds, with second pair strongly reduced in size; podobranch on second maxillipeds slightly reduced, arthrobranch on first pereiopod absent (Liang et al. 1999). Pereiopods. Epipods present on first to fourth pereiopods. First pereiopod short, robust, reaching end of basal segment of antennular peduncle; chela 1.91 – 2.75 (median 2.28) × as long as wide, 1.17 – 1.69 (median 1.41) × length of carpus; tips of fingers rounded, without hook; dactylus 0.77 – 1.18 (median 0.97) × as long as palm; carpus excavated strongly anteriorly, 1.6 – 2.29 (median 2.0) × as long as wide; carpus 0.79 – 1.0 (median 0.84) × length of merus; merus 2.5 – 3.6 (median 3.0) × as long as wide, longer than ischium (Fig. 11 A). Second pereiopod long, slender, reaching beyond distal end of antennular peduncle; chela 2.11 – 3.63 (median 2.75) × as long as wide, 0.63 – 0.87 (median 0.76) × length of carpus; tips of fingers rounded, without hook; dactylus 0.92 – 1.4 (median 1.29) × as long as palm; carpus 4.6 – 6.0 (median 5.0) × as long as wide, 0.74 – 1.17 (median 1.0) × as long as merus; merus 4.8 – 7 (median 5.8) × as long as wide, longer than ischium (Fig. 11 B). Third pereiopod slender, reaching beyond distal end of antennular peduncle by its dactylus, terminating in one claw, with five to six accessory spiniform setae on flexor margin, dactylus 2.67 – 4.0 (median 3.0) × as long as wide (terminal claw and spiniform setae on flexor margin included), propodus 9.75 – 12 (median 10.13) × as long as wide, 3.89 – 5.13 (median 4.44) × as long as dactylus; carpus 4 – 5.5 (median 4.5) × as long as wide, 0.49 – 0.69 (median 0.6) × as long as propodus, 0.43 – 0.56 (median 0.47) × as long as merus; merus 5.63 – 7.86 (median 7.01) × as long as wide, bearing three strong, movable spiniform setae on posterior margin of outer surface; ischium with one small movable spiniform seta (Fig. 11 C, D). Fifth pereiopod slender, reaching to end of third segment of antennular peduncle, dactylus 3.67 – 7 (median 4.17) × as long as wide (terminal claw and spiniform setae on flexor margin included), terminating in one large claw, with 41 – 58 spiniform setae on flexor margin; propodus 10.75 – 14.67 (median 12.38) × as long as wide, 3.31 – 4.82 (median 4.01) × length of dactylus; carpus 4.17 – 6.25 (median 5) × as long as wide, 0.42 – 0.54 (median 0.48) × as long as propodus, 0.49 – 0.71 (median 0.58) × as long as merus; merus 6.5 – 8.6 (median 7.3) × as long as wide, bearing 3 strong, movable spiniform setae on posterior margin of outer surface, ischium without movable spiniform setae (Fig. 11 E, F). Pleopods. Endopod of male first pleopod extending to 0.52 of exopod, elongated and kidney-shaped, 2.14 – 2.57 (median 2.43) × as long as proximal width, inner margin concave, outer margin slightly convex, rounded distally, long pappose setae on outer and distal margins, medium-length setae on inner margin; appendix interna long, exceeding terminal margin of endopod by 0.43 its length (Fig. 11 G, H). Appendix masculina of male second pleopod slender, reaching to proximal 0.63 endopod length, 6.73 × as long as distal width, stick-shaped, with some short spiniform setae on outer surface and some long spiniform setae on distal surface; appendix interna at the middle of appendix masculina, small, extending ~ 0.66 length of appendix masculina (Fig. 11 I, J).	en	Do, Van Tu, Phan, Thi Yen, von Rintelen, Kristina, Le, Hung Anh, von Rintelen, Thomas (2025): Descriptions of four new species of atyid shrimp (Crustacea, Decapoda, Atyidae) in Vietnam. ZooKeys 1247: 151-186, DOI: 10.3897/zookeys.1247.148607, URL: https://zookeys.pensoft.net/article/148607/download/xml/
EE5C738F20385400A0C0893854EE65A7.taxon	etymology	Etymology. The new species is named after the type locality, Tan Son District. The name is used as a noun in apposition.	en	Do, Van Tu, Phan, Thi Yen, von Rintelen, Kristina, Le, Hung Anh, von Rintelen, Thomas (2025): Descriptions of four new species of atyid shrimp (Crustacea, Decapoda, Atyidae) in Vietnam. ZooKeys 1247: 151-186, DOI: 10.3897/zookeys.1247.148607, URL: https://zookeys.pensoft.net/article/148607/download/xml/
EE5C738F20385400A0C0893854EE65A7.taxon	distribution	Distribution. This species has only been recorded in the highland streams of Tan Son District, Phu Tho Province at altitudes from 200 m to 500 m. The estimated area of occupancy is less than 1000 km 2.	en	Do, Van Tu, Phan, Thi Yen, von Rintelen, Kristina, Le, Hung Anh, von Rintelen, Thomas (2025): Descriptions of four new species of atyid shrimp (Crustacea, Decapoda, Atyidae) in Vietnam. ZooKeys 1247: 151-186, DOI: 10.3897/zookeys.1247.148607, URL: https://zookeys.pensoft.net/article/148607/download/xml/
A50CBB9C1CBD5F7390305EBBFC07B754.taxon	description	Figs 6, 7, 8	en	Do, Van Tu, Phan, Thi Yen, von Rintelen, Kristina, Le, Hung Anh, von Rintelen, Thomas (2025): Descriptions of four new species of atyid shrimp (Crustacea, Decapoda, Atyidae) in Vietnam. ZooKeys 1247: 151-186, DOI: 10.3897/zookeys.1247.148607, URL: https://zookeys.pensoft.net/article/148607/download/xml/
A50CBB9C1CBD5F7390305EBBFC07B754.taxon	diagnosis	Diagnosis. Caridina xuanlien sp. nov. is characterized by several morphological characters such as short rostrum, just reaching to beginning of the third segment of antennular peduncle; stylocerite reaching to beginning of second segment of antennular peduncle (Fig. 6 A, B); dactylus of first pereiopod longer than palm (Fig. 7 A); short, kidney-shaped endopod of male first pleopod, extending to 2.79 × exopod, with well-developed appendix interna, slightly exceeding terminal margin of endopod by 0.23 its length (Fig. 7 G, H); short and stick-shaped appendix masculina of male second pleopod, reaching to proximal 0.43 × endopod length, with narrow and small appendix interna, extending ~ 0.6 × length of appendix masculina (Fig. 7 I, J).	en	Do, Van Tu, Phan, Thi Yen, von Rintelen, Kristina, Le, Hung Anh, von Rintelen, Thomas (2025): Descriptions of four new species of atyid shrimp (Crustacea, Decapoda, Atyidae) in Vietnam. ZooKeys 1247: 151-186, DOI: 10.3897/zookeys.1247.148607, URL: https://zookeys.pensoft.net/article/148607/download/xml/
A50CBB9C1CBD5F7390305EBBFC07B754.taxon	description	Description. Cephalothorax and cephalic appendages. Carapace length 3.6 – 4.8 mm (median 4.3 mm, n = 20). Rostrum short and slender, slightly downward, reaching to beginning of the third segment of antennular peduncle, 0.1 – 0.2 (median 0.2) × as long as carapace, rostral formula 2 – 7 + 3 – 9 / 0 – 2 (Fig. 6 A). Suborbital angle acute, completely fused with antennal spine; pterygostomian margin rounded, slightly produced forward (Fig. 6 A). Eyes well developed with globular cornea, anterior end reaching to 0.7 × length of basal segment of antennular peduncle (Fig. 6 A). Antennular peduncle 0.6 – 0.74 (median 0.64) × as long as carapace; basal segment 1.63 – 2.0 (median 1.88) × as long as second segment, second segment 1.17 – 1.4 (median 1.33) × as long as third segment (Fig. 6 B). Stylocerite reaching to beginning of second segment of antennular peduncle (Fig. 6 B). Scaphocerite elongated ovate, reaching beyond distal end of antennular peduncle, 2.68 – 2.88 (median 2.86) × as long as wide (Fig. 6 A, C). Abdominal somites, telson, and uropods. Sixth abdominal somite 0.47 – 0.5 (median 0.47) × length of carapace, 1.47 – 1.62 (median 1.58) × as long as fifth abdominal somite, 0.85 – 0.95 (median 0.91) × length of telson. Telson 2.4 – 3.25 (median 2.75) × as long as proximal wide, distal margin triangular, terminating in a short median projection, with five or six pairs of dorsal spiniform setae and one pair of dorso-subdistal spiniform setae; distal end with three or four pairs of spiniform setae, lateral pair shorter than intermediate pairs (Fig. 6 D, E). Preanal carina low ,, with few setae, lacking a spine (Fig. 6 F). Uropodal diaeresis with 18 – 21 (median 21) movable spiniform setae, outermost shorter than lateral angle (Fig. 6 G). Mouthparts and branchiae. Incisor process of mandible ending in one row of six or seven irregular teeth, molar process truncated (Fig. 6 H). Lower lacinia of maxillula broadly rounded, upper lacinia elongated, with a several distinct teeth and setae on inner margin, palp stout with few simple setae at tip (Fig. 6 I). Upper endites of maxilla subdivided, palp short, scaphognathite tapering posteriorly, with numerous long, curved setae at posterior margin (Fig. 6 J). Distal end of palp of first maxilliped triangular, with a short projection; flagellum of the exopod very elongated, endopod reaching 0.8 × length of flagellum of exopod (Fig. 6 K, L). Podobranch of second maxilliped slightly reduced, with few finger-like projections (Fig. 6 M). Third maxilliped reaching near the end of antennular peduncle, ending in single terminal claw, exopod reaching 0.3 × length of penultimate segment; ultimate segment slightly longer penultimate segment; epipod present on the coxa (Fig. 6 N). Branchial formula as typical for Paracaridina genus, five pairs of pleurobranchs well developed; two pairs of arthrobranchs on third maxillipeds, with second pair strongly reduced in size; one pair of podobranchs on second maxillipeds slightly reduced, arthrobranch on first pereiopod absent (Liang et al. 1999). Pereiopods. Epipods present on first to fourth pereiopods. First pereiopod short, robust, reaching end of basal segment of antennular peduncle; chela 2.08 – 2.29 (median 2.12) × as long as wide, 1.21 – 1.47 (median 1.40) × length of carpus; tips of fingers rounded, without hook; dactylus longer than palm, 1.0 – 1.07 (median 1.03) × as long as palm; carpus excavated strongly anteriorly, 1.5 – 1.87 (median 1.73) × as long as, respectively; carpus 0.78 – 0.91 (median 0.84) × length of merus; merus 2.65 – 3.54 (median 3.33) × as long as wide, longer than ischium (Fig. 7 A). Second pereiopod long, slender, reaching to distal end of antennular peduncle; chela 2.65 – 3.0 (median 2.86) × as long as wide, 0.66 – 0.74 (median 0.73) × length of carpus; tips of fingers rounded, without hook; dactylus 1.42 – 1.58 (median 1.46) × as long as palm; carpus 5.25 – 6.21 (median 5.6) × as long as wide, 1.05 – 1.21 (median 1.16) × as long as merus; merus 5.46 – 6.0 (median 5.71) × as long as wide, longer than ischium (Fig. 7 B). Third pereiopod slender, reaching beyond distal end of antennular peduncle by its dactylus, terminating in one claw, with five accessory spiniform setae on flexor margin, dactylus 3.29 – 4 (median 3.57) × as long as wide (terminal claw and spiniform setae on flexor margin included), propodus 8.9 – 9.44 (median 9.0) × as long as wide, 3.24 – 4.0 (median 3.71) × as long as dactylus; carpus 4.2 – 4.92 (median 4.83) × as long as wide, 0.69 – 0.78 (median 0.72) × as long as propodus, 0.5 – 0.57 (median 0.56) × as long as merus; merus 5.75 – 6.82 (median 6.0) × as long as wide, bearing three strong, movable spiniform setae on posterior margin of outer surface; ischium with one small movable spiniform seta (Fig. 7 C, D). Fifth pereiopod slender, reaching to end of third segment of antennular peduncle, dactylus 3.33 – 3.75 (median 3.5) × as long as wide (terminal claw and spiniform setae on flexor margin included), terminating in one large claw, with 37 – 40 spiniform setae on flexor margin; propodus 10.88 – 13.13 (median 11.88) × as long as wide, 3.22 – 3.53 (median 3.33) × length of dactylus; carpus 4.15 – 4.36 (median 4.28) × as long as wide, 0.52 – 0.55 (median 0.55) × as long as propodus, 0.6 – 0.69 (median 0.62) × as long as merus; merus 5.83 – 7.17 (median 6.57) × as long as wide, bearing 3 strong, movable spiniform setae on posterior margin of outer surface, ischium without movable spiniform setae (Fig. 7 E, F). Pleopods. Endopod of male first pleopod extending to 0.59 × exopod, kidney-shaped, anterior part not folded backwards, 2.75 – 3.05 (median 2.79) × as long as proximal width, inner margin concave, outer margin slightly convex, rounded distally, long pappose setae on outer and distal margins, medium-length setae on inner margin; with appendix interna curved upwards, slightly exceeding terminal margin of endopod by 0.23 of its length (Fig. 7 G, H). Appendix masculina of male second pleopod slender, reaching to proximal 0.6 × endopod length, 8.25 × as long as distal width, stick-shaped, with some short spiniform setae on outer surface and some long spiniform setae on distal surface; appendix interna at the middle of appendix masculina, narrow, small, extending ~ 0.60 length of appendix masculina (Fig. 7 I, J).	en	Do, Van Tu, Phan, Thi Yen, von Rintelen, Kristina, Le, Hung Anh, von Rintelen, Thomas (2025): Descriptions of four new species of atyid shrimp (Crustacea, Decapoda, Atyidae) in Vietnam. ZooKeys 1247: 151-186, DOI: 10.3897/zookeys.1247.148607, URL: https://zookeys.pensoft.net/article/148607/download/xml/
A50CBB9C1CBD5F7390305EBBFC07B754.taxon	etymology	Etymology. The new species is named after the type locality, Xuan Lien National Park. The name is used as a noun in apposition.	en	Do, Van Tu, Phan, Thi Yen, von Rintelen, Kristina, Le, Hung Anh, von Rintelen, Thomas (2025): Descriptions of four new species of atyid shrimp (Crustacea, Decapoda, Atyidae) in Vietnam. ZooKeys 1247: 151-186, DOI: 10.3897/zookeys.1247.148607, URL: https://zookeys.pensoft.net/article/148607/download/xml/
A50CBB9C1CBD5F7390305EBBFC07B754.taxon	distribution	Distribution. This species has been found only in the upland streams of Thuong Xuan District, Thanh Hoa Province, with elevations from 130 m to 600 m. The estimated area of occupancy is less than 1000 km 2.	en	Do, Van Tu, Phan, Thi Yen, von Rintelen, Kristina, Le, Hung Anh, von Rintelen, Thomas (2025): Descriptions of four new species of atyid shrimp (Crustacea, Decapoda, Atyidae) in Vietnam. ZooKeys 1247: 151-186, DOI: 10.3897/zookeys.1247.148607, URL: https://zookeys.pensoft.net/article/148607/download/xml/
