Caridina lobocensis Cai, Choy & Ng, 2009

Mazancourt, Valentin de, Marquet, Gérard & Keith, Philippe, 2024, An Integrative Taxonomic Revision of the Freshwater Atyid Shrimps (Crustacea: Decapoda: Caridea) of Micronesia, Diversity 16 (200), pp. 1-31 : 14-17

Caridina lobocensis Cai, Choy & Ng, 2009

Figures 3D and 6.

- Caridina lobocensis Cai, Choy, and Ng, 2009: 68 , Figures 2–4 [type locality: Tributary of Loboc River, Loboc (approx. 9 ◦ 38.206 ′ N, 124 ◦ 1.807 ′ E), Bohol Island, Philippines];

-? Caridina lobocensis —de Mazancourt et al., 2019 [47]: 166, Figures 2–5.

Material examined

PALAU: Babeldaob Island . MNHN-IU-2024-455 (DNA: CA1552 ): 1 ♀ ovig. cl 4.6 mm and MNHN-IU-2024-456 (DNA: CA1553 ): 1 ♀ ovig. cl 4.2 mm, Ngerchokl river ( Station 2), 07 ◦ 36.527 ′ N, 134 ◦ 36.958 ′ E, 27 February 2011, coll. M. Castelin, P. Keith, P. Gerbeaux, G. Marquet, and L. Taillebois. MNHN-IU-2024-457 (DNA: CA1056 ): 1 ♀ ovig. cl 4.2 mm and MNHN-IU-2024-458 (DNA: CA1554 ): 1 ♀ ovig. cl 4.3 mm, Tireloich river ( Station 3 ), 07 ◦ 41.417 ′ N, 134 ◦ 37.754 ′ E, 28 February 2011, coll. M. Castelin, P. Keith, P. Gerbeaux, G. Marquet, and L. Taillebois. MNHN-IU-2024-459 (DNA: CA1555 ): 1 ♀ ovig. cl 4.3 mm, West Coast stream Northern Tip ( Station 4 ), 07 ◦ 43.056 ′ N, 134 ◦ 36.924 ′ E, 28 February 2011, coll. M. Castelin, P. Keith, P. Gerbeaux, G. Marquet, and L. Taillebois. MNHN-IU-2024- 460 (DNA: CA1556 ): 1 ♀ ovig. cl 4.4 mm, Ngermeskang river ( Station 6 ), 75 m a.s.l., 07 ◦ 32.484 ′ N, 134 ◦ 34.670 ′ E, 1 March 2011, coll. M. Castelin, P. Keith, P. Gerbeaux, G. Marquet, and L. Taillebois. USNM 105446 : 2 ♀, cl 4.3–4.8 mm and 1 juv. cl 2.3 mm, Station 122 , 7 ◦ 42.885 ′ N, 134 ◦ 37.386 ′ E, 23 August 1955, Coll. F.M. Bayer. USNM 105447 : 2 ♀ ovig., cl 4.4–5.0 mm and a juv. cl 3.0 mm, Station 241 , 7 ◦ 32.833 ′ N, 134 ◦ 35.766 ′ E, 18 October 1955, coll. H.A. Fehlmann. USNM 105448 : 1 ♀ ovig., cl 3.0 mm and 2 ♀, cl 3.0– 3.9 mm, Arakitaoch river , cascade zone , 7 ◦ 31.557 ′ N, 134 ◦ 34.202 ′ E, 4 November 1956, coll. H.A. Fehlmann. Koror Island: USNM 105445 : 2 ♀, 4.5–4.9 mm, Station 194 , 7 ◦ 20.421 ′ N, 134 ◦ 29.642 ′ E, 30 September 1955, coll. H.A. Fehlmann.

THE PHILIPPINES. RMNH.CRUS.D.54659 : 1 ♀ ovig., cl 7.1 mm, Barrio Mainit , Tayabas , Quezon Province, Luzon , 2 November 1986, coll. D.S. Bale.

Description

Cephalothorax. Suborbital angle indistinguishably fused with antennal spine. Pterygostomian margin rounded. Rostrum ( Figure 6k): straight, short, 0.4–0.5 times length of cl, reaching middle of the third segment of antennular peduncle, armed with 12–17 teeth on dorsal margin, 1–3 of them situated on carapace behind orbital margin, ventral margin with 2–3 teeth.

Eyes well-developed, anterior end reaching to 0.7 times length of basal segment of antennular peduncle. Antennular peduncle 0.54 times as long as carapace. Anterolateral angle reaching 0.28 times length of the second segment, second segment slightly shorter than third segment. Stylocerite reaching to the basal segment of antennular peduncle.

Pereiopods. Epipods on first four pereiopods. P1 ( Figure 6a): chela about 1.3–1.6 times as long as wide, movable finger 1.9–2.4 times as long as wide, 0.5–0.7 times length of palm; carpus 1.3–1.6 times as longas wide. P2 ( Figure 6b) more slender and longer than first pereiopod with chela 2.2–2.8 times as long as wide: movable finger 3.5–5.0 times as long as wide, 1.3–1.7 times length of palm; carpus slender 4.3–5.5 times as longas wide. P3 ( Figure 6c): stout, dactylus ( Figure 6e) 3.7–4.4 times as longas wide (terminal spiniform seta included) terminating in two very strong claws with four-five spiniform setae on flexor margin; propodus 7.3–9.9 times as longas wide, 3.7–4.4 times as longas dactylus. P5 ( Figure 6d): dactylus ( Figure 6f) with two strong claws, 2.5–3.7 as long as wide with 31–33 spiniform setae on flexor margin; propodus 11.7–14.3 times as long as wide, 4.3–7.4 times as long as dactylus.

Abdomen. Third abdominal somite with moderately convex dorsal profile. Sixth abdominal somite 0.45 times as long as carapace, 1.3 times as long as fifth somite, and 0.77 times as long as telson.

Telson ( Figure 6g) two times as long as wide, with four pairs of dorsal spinules and one pair of dorsolateral spinules; posterior margin without a median process, rounded with from seven to nine very long intermediate plumose setae longer than lateral ones.

Pl1 and Pl2: no males in our collected specimens. According to Cai et al. [50], “Endopod of male first pleopod subtriangular, half-length of exopod, appendix interna stout, exceeding end of endopod. Appendix masculina of male second pleopod 2/3 length of endopod, with appendix interna reaching base of distal one-third of appendix masculina”.

Uropodal diaeresis ( Figure 6i) with 16–21 spinules.

Pre-anal carina ( Figure 6j) elevated, without spine but with a few stiff setae.

Ovigerous females with eggs sized 0.37–0.43 mm × 0.22–0. 27 mm ( Figure 6h).

Habitat

This species is largely rheophile and prefers waters that are fresh and fast-flowing waters the lower to the higher courses.

Colour pattern

Unknown.

Distribution

This species has been found in Palau and the Philippines.

Remarks

Our specimens agree well with those described from Bohol Island (Philippines) by Cai et al. [50] in relation to their long stylocerite, their stout first pereiopod, their short fingers, their third to fifth pereiopods ending in two claws, and their egg size. The rostrum in our specimens seems shorter: reaching the middle of the third segment of antennular peduncle (vs. reaching slightly beyond end of antennular peduncle) and its pterygostomian margin is rounded (vs. pterygostomian margin subrectangular), but we consider these differences to be within intra-specific variability. This species is closely related to C. buehleri and C. gueryi, both recently re-described by de Mazancourt et al. [43], but they are clearly separated in our molecular analyses and they can be distinguished by its P1 chela 1.3–1.6 times as long as wide (vs. 2.2–2.3 for C. buehleri and 1.9–2.4 for C. gueryi), and by its P5 dactylus with two strong claws (vs. one strong claw for C. buehleri and C. gueryi). Its P2 carpus is 4.3–5.5 times as long as wide and its P5 propodus is 4.3–7.4 times as long as its dactylus (vs., respectively, 5.5–6.2 and 3.8–4.1 for C. buehleri). Its rostrum is armed with dorsal teeth, one–three of them situated on carapace behind orbital margin (vs. three–five for C. gueryi) and its P5 dactylus has 31–33 spiniform setae on its flexor margin (vs. 26–31 for C. gueryi).