Caridina syriaca Bouvier, 1904

Klotz, Werner, von Rintelen, Thomas & Christodoulou, Magdalini, 2019, Middle East Caridina (Decapoda: Atyidae): Redescription of C. fossarum Heller, 1862, description of three new species, and remarks on the status of C. syriaca Bouvier, 1904 and C. babaulti basrensis Al-Adhub & Hamzah, 1987, Zoologischer Anzeiger 283, pp. 161-185 : 168-170

Caridina syriaca Bouvier, 1904

( Fig. 7 )

Material examined

Syntypes. 1 ♀ cl 4.7 mm in poor condition, Syrie, leg. Letourneux, 1882, MNHN-IU-2013-11299 (= MNHN-Na906) ; remainings of 1 specimen, probably female, Syrie, leg. Letourneux, 1882, MNHN-IU-2013-11298 (= MNHN-Na906) ; components of 6 specimens cl 4.5 – 4.7 mm including 3 abdomens with eggs, Syrie, leg. Letourneux, 1882, MNHN-IU-2013-11297 (= MNHN-Na905) .

Description

Cephalothorax and cephalic appendages. Medium-sized shrimp with carapace length 4.5 – 4.7 mm in apparently adult specimens (n = 8). Carapace ( Fig. 7 A ) smooth, antennal spine slightly separated from the inferior orbital angle, pterygostomial angle rounded. Rostrum reaching to end of second segment of antennular peduncle in the female specimen with collection number MNHN-IU-2013- 11299 (= MNHN-Na906); conserv/ation status of other material is too bad to obtain relative rostrum length, 0.71 – 0.95 (median 0.74, n = 3) times carapace length, slightly sigmoid or straight, dorsal teeth arranged closely until near to tip or distal 0.12 of rostrum unarmed, ventral teeth placed near midlength of rostrum; rostrum formula 1 – 2 + 14 – 23/1 – 8. Eyes well developed with pigmented cornea globular. Antennula and antenna well developed. Antennular peduncle ( Fig. 7 B ) 0.62 – 0.76 (n = 2) times as long as carapace, first segment 2.06 – 2.61 (n = 2) times as long as second segment, distolateral angle with an acute projection 0.33 – 0.47 (n = 2) times as long as second segment; second segment 1.50 – 2.13 (n = 2) times length of third segment. Stylocerite pointed, reaching to 0.98 – 1.00 (n = 2) times length of basal segment of antennular peduncle. Scaphocerite ( Fig. 7 C ) with well-developed distolateral tooth, 3.19 – 3.81 (median 3.67, n = 3) times as long as wide.

Abdominal somites, telson and uropods. Sixth abdominal somite 0.56 (n = 1) times length of carapace, 1.66 – 2.00 (median 1.79, n = 4) times as long as fifth somite, as long as telson (n = 2). Telson ( Fig. 7 D, G ) slightly tapering distally, distal margin convex without a median projection, lateral angles not overreaching distal margin, dorsal with 3 or 4 (n = 3) pairs of short spiniform setae and one pair of short spiniform setae dorsolateral; distal margin with one pair of strong lateral spiniform setae and about 8 thin setae medial, longer than lateral ones. Uropodal diaeresis ( Fig. 7 E ) with 11 – 13 (n = 3) spiniform setae, outer one slightly shorter than lateral angle.

Mouthparts and branchiae. Third maxilliped slender, with ultimate segment slightly longer than penultimate segment. Well-developed epipods (with hooks on distal end) present on third maxilliped and first 4 pereiopods.

Pereiopods. First and second pereiopods chelate. Chela of first pereiopod ( Fig. 7 F ) caridinoid in shape, with well-developed palm, 2.0 (n = 1) times as long as wide, 1.2 (n = 1) times as long as carpus; tips of fingers rounded, without hooks but tufts of setae distally; dactylus 2.74 (n = 1) times as long as wide, 1.0 (n = 1) times as long as palm; carpus slender, very slightly excavated distally, 2.22 – 2.56 (n = 2) times as long as wide, 0.98 (n = 2) times as long as merus. Merus not inflated, 3.50 – 3.57 (n = 2) times as long as wide, 1.24 (n = 1) times as long as ischium. Merus of second pereiopod not inflated, 5.0 – 5.18 (n = 2) times as long as wide, 1.14 – 1.15 times as long as ischium: Carpus of fifth pereiopod 5.0 (n = 1) times as long as wide, 0.47 – 0.52 (n = 2), 0.65 (n = 1) times as long as merus, with 1 strong spiniform setae near distal margin and 3 tiny spiniform setae on flexor margin; merus 8.40 (n = 1) times as long as wide, 1.53 (n = 1) times as long as carpus, bearing 1 strong movable spiniform setae on externo-inferior margin. Ischium of this leg without a spiniform seta.

Reproductive biology. Ovigerous females with few large eggs; size of undeveloped eggs (without eyes) 0.83 – 0.92 × 0.54 – 0.56 mm.

Size. Postorbital carapace length of apparently adult specimens 4.5 – 4.7 mm.

Colouration. Unknown.

Distribution. This species is reported from Syria, but the exact collection details are unknown ( Fig. 1 B ).

Remarks. As already mentioned by Bouvier in 1904, the type material of C. syriaca is in a very poor condition. It consists of one female and remnants of another, probably female specimen, and a vial containing components of six specimens. Bouvier himself was in doubt about the identity of this species and stated that it might be conspecific to C. fossarum . Later ( Bouvier 1925) he considered C. syriaca a valid species, though. More recently, C. syriaca again was treated as a junior synonym of C. fossarum ( Grave & Fransen 2011) . Despite the poor conservation status of this material, characters of the telson of two specimens are clearly showing that C. syriaca is different from C. fossarum . In the latter, the outermost spiniform setae on the distal margin of the telson are longer than the intermediate ones (vs. outermost setae shorter than median ones). This character was also shown by Bouvier (Fig. 479, p. 215) in his monograph on atyid shrimp ( Bouvier 1925). This character also distinguishes C. syriaca from Caridina shahrazadae sp. nov. found in Iran. In the shape of the rostrum, the slender carpi of the first pair of pereiopods and the telson with intermediate setae longer than lateral spiniform setae, C. syriaca is very similar to Caridina togoenis Hilgendorf, 1893 described from northern and central Africa ( Richard & Clark 2009). While it seems rather unlikely that the same species occurs in these two geographically widely separated areas (and the possibility of mislabelling samples cannot be excluded), the limited characters that could be studied in the syntype material do not allow to decide whether C. syriaca is different from Caridina togoensis or must be treated as a junior synonym of the latter. No recent material of C. syriaca was available for the present study.

Figures

Fig. 7. Caridina syriaca Bouvier,1904, female, MNHN-IU-2013-11297:A, cephalothorax; B, antennula; C, antenna; D, telson; E, uropodal diaeresis; F, first pereiopod; G, terminal part of telson. Scale bars indicates 1 mm (A̅D, F) and 0.5 mm (E, G).

Fig. 1. A, Origin of sequenced specimens (for details see Table 1); B, Map showing the geographic distribution of Caridina species in the Middle East.