Caridina buergersi, Karge & Rintelen & Klotz, 2010

Karge, Andreas, Rintelen, Kristina Von & Klotz, Werner, 2010, On two small collections of freshwater shrimps (Decapoda: Atyidae: Caridina) from Papua New Guinea, with descriptions of two new species *, Zootaxa 2372 (1), pp. 138-150 : 146-149

publication ID	https://doi.org/ 10.11646/zootaxa.2372.1.14
persistent identifier	https://treatment.plazi.org/id/03C687A6-EA0A-FFB4-FF01-0B18452FFC67
treatment provided by	Felipe
scientific name	Caridina buergersi
status	sp. nov.

Treatment

Caridina buergersi View in CoL sp. nov.

( Figs. 5–6 View FIGURE 5 View FIGURE 6 )

Material examined. Holotype male, cl 3.30 ( ZMB 17166), Papua New Guinea, former “Deutsch- Neuguinea”, near Mäanderberg, coll. Bürgers. Paratypes: 5 females, cl 2.90–4.10 mm ( ZMB 17166), same data as holotype ; 1 ov. female (eggs without eyes), cl 4.00 mm ( ZMB 17166) , 6 males, cl 3.10–3.40 mm ( ZMB 17166), same data as holotype . 4 juveniles, cl 1.70–3.00 mm ( ZMB 17166), same data as holotype .

Diagnosis. Rostrum ( Fig. 5A View FIGURE 5 ) straight or slightly sigmoid, with a basal crest, reaching to end of or beyond antennular peduncle, or to distal end of the scaphocerite, rostral formula: 2–3(3) + 17–21(19) + 0–2(0) / 5– 11(7). Pterygostomial angle ( Fig. 5B View FIGURE 5 ) obtuse, mostly with a distinct tooth. Preanal carina almost absent or flattish without a tooth or spine. Chela of first pereiopod 1.94–2.71 as long as wide, dactylus 1.06–1.30 as long as palm; carpus 2.40–3.10 times as long as wide (juvenile specimen 2.18). Chela of second pereiopod 2.26–2.94 times as long as wide, dactylus 1.11–1.60 times as long as palm; carpus 5.17–6.67 times as long as wide.

Description. Rostrum ( Fig. 5A View FIGURE 5 ) straight or slightly sigmoid, with a basal crest, reaching to end of or beyond antennular peduncle, or to distal end of the scaphocerite, 0.73–0.99 times as long as carapace, armed dorsally with 21–24 teeth including 2 or 3 on the carapace posterior to orbital margin, armature reaching almost to the distal end with 0–2 supapical-like teeth, 5–11 ventral teeth; rostral formula: 2–3(3) + 17–21(19) + 0–2(0) / 5–11(7). Juvenile specimens differ in rostral length (reaching to end of second segment of antennular peduncle or end of third segment, 0.57–0.71 times carapace length) and number of teeth; rostral formula: 2–3 + 12–15 + 0 / 2–5.

Antennal spine below inferior orbital angle. Pterygostomial angle ( Fig. 5B View FIGURE 5 ) obtuse, with a distinct tooth in 13 of 17 specimens. Antennular peduncle 0.70–0.93 times as long as carapace, second segment 2.00–2.13 times length of third segment, third segment 0.24–0.25 times as length of basal segment. Stylocerite 0.80–0.85 times as long as the basal segment of antennular peduncle. Scaphocerite ( Fig. 5C View FIGURE 5 ) 3.7 times as long as wide.

Sixth abdominal somite 0.58–0.67 times length of carapace, 1.8–2.2 times as long as fifth somite, as long as or slightly shorter than telson. Telson ( Figs. 6G–H View FIGURE 6 ) 3.1–3.6 times as long as proximal width, distal margin convex or rounded, without median projection, with 3 or 4 pairs dorsal and 1 pair of dorsolateral spinules, dorsal spinules located close to lateral margin of telson, distal end with 6–8 relatively short spines, lateral pair slightly longer than intermediate spines. Preanal carina almost absent or flattish without a tooth or spine. Uropodal diaeresis ( Fig. 6I View FIGURE 6 ) with 12–15 movable spinules.

Incisor process of mandible ( Fig. 5D View FIGURE 5 ) ending in irregular teeth, molar process truncated. Lower lacinia of maxillula ( Fig. 5E View FIGURE 5 ) rounded, upper lacinia elongate, with numerous distinct teeth on inner margin, palp slender with few simple setae at tip. Upper endites of maxilla ( Fig. 5F View FIGURE 5 ) subdivided, palp short, scaphognathite tapering posteriorly, fringed with long, curved setae at posterior margin. Palp of first maxilliped ( Fig. 5G View FIGURE 5 ) ending in a distinct finger-like projection. Podobranch on second maxilliped ( Fig. 5H View FIGURE 5 ) well developed. Third maxilliped ( Fig. 5I View FIGURE 5 ) with 2 arthrobranchs, ultimate segment shorter than penultimate segment. Pleurobranchs present on all pereiopods. First pereiopod with 1 arthrobranch. Well developed epipods present on the third maxilliped and the first 4 pereiopods.

Chela and carpus of first pereiopod ( Figs. 6A–B View FIGURE 6 ) distinctly stouter and broader than chela and carpus of second pereiopod; chela of first pereiopod 1.94–2.71 as long as wide, 1.07–1.28 times length of carpus; tips of fingers without hooks; dactylus 1.06–1.30 as long as palm; carpus 2.4–3.1 times as long as wide (juvenile specimen 2.18), 0.76–1.12 times length of merus. Chela of second pereiopod 2.26–2.94 times as long as wide, 0.66–0.82 times length of carpus; tips of fingers rounded, dactylus 1.11–1.60 times as long as palm; carpus 5.17–6.67 times as long as wide, 1.24–1.36 times length of merus (juvenile specimen 1.10). Third pereiopod ( Figs. 6C–D View FIGURE 6 ) slender, dactylus 2.8–4.1 times as long as wide (terminal spine included, without spines on flexor margin), terminating in one large claw with 4–6 accessory spines on flexor margin; propodus 11.4–15.1 times as long as wide (juvenile specimen 9.8), 4.32–4.53 times as long as dactylus (juvenile specimen 3.5); carpus 4.63–6.0 times as long as wide, 0.55–0.66 times as long as propodus, 0.46–0.54 times as long as merus; merus 7.60–9.20 times as long as wide, 1.84–2.16 times as long as carpus, bearing 2–3 movable spines on posterior margin of outer surface. Fifth pereiopod ( Figs. 6E–F View FIGURE 6 ) slender, dactylus 5.0 times as long as wide (terminal spine included, without spines on flexor margin), terminating in one large claw with 37–45 spinules on flexor margin; propodus 12.55–13.57 times as long as wide, 3.29–3.96 times length of dactylus, carpus 4.67–5.63 times as long as wide, 0.44–0.50 times as long as propodus, 0.57 times as long as merus; merus 7.4–8.7 times as long as wide, 1.76 times length of carpus, bearing 2 or 3 strong, movable spines on posterior margin of outer surface.

Endopod of male first pleopod ( Fig. 6J View FIGURE 6 ) elongated triangular, two times as long as proximal width, less than 0.3 times as long as exopod, without an appendix interna but with shoulder-like interruption near distal end. Appendix masculina on male second pleopod ( Fig. 6K View FIGURE 6 ) slender, rod-like, with long spines on inner and distal margin, appendix interna reaching to about three-quarters of appendix masculina.

Egg size 0.84 × 0.41 mm

Etymology. Caridina buergersi is dedicated to Dr. J. Bürgers, a member of the Sepik expedition 1912/ 1913 to New Guinea. The name is used as a noun in apposition.

Remarks. The studied sample belongs to historical material deposited in the crustacean collection of the Museum für Naturkunde Berlin (ZMB). It was labelled as “ Caridina sarasinorum, Deutsch-Neuguinea ” and collected on the German Sepik-Expedition in 1912–13 by Dr. J. Bürgers. In C. sarasinorum , a species regarded as endemic to the Lake Poso in central Sulawesi, Indonesia, the distal part of the rostrum is unarmed on dorsal margin and epipods are present on the first pair of pereiopods only ( Cai & Wowor, 2007). The rostrum of the present material is armed almost to the distal end with 0–2 supapical-like teeth on dorsal margin and epipods are well developed on first to fourth pereiopods. Due to this differences the present specimen could not assigned to this species and is proposed as new to science. In the shape and armature of the rostrum (armed up to tip on dorsal margin, unarmed near tip on ventral margin) Caridina buergersi resembles C. cognata , but differs by having a distinct tooth on the pterygostomial margin of the carapace in 13 out of 17 specimens examined (vs. pterygostomial margin without a tooth in C. cognata ). Furthermore, C. buergersi differs by its more slender carpi of the first (2.4–3.1 times as long as wide vs. 1.61–1.95 times in C. cognata ) and second pereiopod (5.17–5.67 times as long as wide vs. 4.00–5.18 times in C. cognata ). The tooth present on the pterygostomial margin in most specimens distinguishes C. buergersi also from all other Caridina species known from Papua New Guinea and the surrounding islands.