Caridina serratirostris De Man, 1892

Shokita, Yixiong Cai Shigemitsu, 2006, Report On A Collection Of Freshwater Shrimps (Crustacea: Decapoda: Caridea) From The Philippines, With Descriptions Of Four New Species, Raffles Bulletin of Zoology 54 (2), pp. 245-270 : 246-247

Caridina serratirostris De Man, 1892

Caridina serratirostris De Man, 1892: 382 , Pl. 23: Fig. 28-28e [type locality: “Bangkalan” and “Bonea” rivers, Selajar, Indonesia]; Bouvier, 1925: 218, Figs. 480-486; Kubo, 1938: 92, Fig. 21; Holthuis, 1965: 25, Fig. 8 ; 1978: 38, Fig. 13a-h; Shokita, 2003: 250, Figs. 18E, 19J, 20M.

Caridina serratirostris serratirostris – Fujino, 1972: 7; Shokita, 1975: 119.

Caridina celebensis – Holthuis, 1978: 39, Fig. 14 a-i; Yeo, Cai & Ng, 1999: 214, Figs. 8 , 9 .

? Caridina serratirostris – Chace, 1997:19, Figs. 11a-r.

Material examined. – 2 ovig. females, cl 3.1-4.1 mm, UR, San Francisco River , Surigao Del Nork, mindanao, Philippines, 25 Jul.1985 ; 2 ovig. females, cl 3.8-3.9 mm, Santacruz River , Palawan, Philippines, 9 Aug.1985 .

Comparative material examined. – Lectotype of Caridina serratirostris De Man, 1892: 1 ovig. female, cl 4.3 mm, syntype of Caridina serratirostris De Man, 1892 , ZMA De 102625, Indonesia Salejer, Bangkalah River, leg. M. Weber, 1888, present destination. Paralectotypes: 3 males, cl 2.6-4.4 mm, 2 females, cl 3.7-5.1 mm, 28 ovig. females, cl 3.7-5.1 mm, data same as lectotype. Others: 1 male, cl 3.0 mm, 5 females, cl 3.1-3.5 mm, 4 ovig. females, cl 3.3- 4.2 mm, ZRC 1996.1753, Sungai Paya, Kampung Paya, Palau Tioman, Malaysia, coll. P. K. L. Ng et al, 25-27 Jun.1996; 2 ovig. females, cl 3.3-3.5 mm, ZRC 1999.0971, Sungai Paya, Kampung Paya, Pulau Tioman, Malaysia, coll. H. H. Tan et al, 26 Jun.1999; 9 males, cl 2.1-2.6 mm, 5 females, cl 3.2-3.5 mm, 14 ovig. females, cl 3.2-3.8 mm, station 2 at Sungai Keliling, Kampung Juara, Pulau Tioman, Malaysia, coll. Y. Cai et al., 7 Sep.2000; 2 males, cl 2.2- 2.3 mm, 6 females, cl 2.9-3.2 mm, 27 ovig. females, cl 3.1-4.0 mm, station 4 at Sungai Keliling, Kampung Juara, Pulau Tioman, Malaysia, coll. Y. Cai et al., Sep.2000; 1 male, cl 2.6 mm, 3 females, cl 3.1-3.5 mm, 6 ovig. females, cl 3.5-3.6 mm, station 8 at Sungai Keliling, Kampung Juara, Pulau Tioman, Malaysia, coll. Y. Cai et al., 8 Sep.2000; 3 females, cl 1.9-3.7 mm, Sungai Baharu, Kampung Juara, Malaysia, coll. Y. Cai, 8 Sep.2000; 1 ovig. female, cl 4.2 mm, ZRC. 2004.0570, 128 ° 07.04'E 26 ° 36.61'N, Arume River, Okinawa Island, Ryukyus, Japan, coll. Y. Cai, N. K. Ng, T. Naruse & S. Islam, 11 Jun.2000; 1 male, cl 3.2 mm, 2 ovig. females, cl 4.9- 5.0 mm, ZRC.2004.0571, 123 ° 52.80'E 24 ° 16.64'N, shallow freshwater stream of Aira River, Iriomote Island, Ryukyus, Japan, coll. Y. Cai, N. K. Ng & T. Naruse, 14 Jun.2000; 1 male, cl 40 mm, 5 ovig. females, cl 4.8-5.3 mm, ZRC.2004.0572, 123 ° 52.74'E 24 ° 16.60'N, shallow freshwater stream, downstream of Aira River, Iriomote Island, Ryukyus, Japan, coll. Y. Cai, N. K. Ng & T. Naruse, 14 Jun.2000; 1 female, cl 4.4 mm, 3 ovig. females, cl 4.4-4.5 mm, ZRC.2004.0573, 123 ° 51.84'E 24 ° 23.65'N, fast flowing water, about 200 meters from sea, Omija River, Iriomote Island, Ryukyus, Japan, coll. Y. Cai, N. K. Ng & T. Naruse, 15 Jun.2000; 1 male, cl 3.4 mm, ZRC.2004.0574, 123 ° 51.84'E 24 ° 23.65'N, fast flowing water, about 200 meters from sea, Omija River, Iriomote Island, Ryukyus, Japan, coll. Y. Cai & T. Naruse, 16 Jun.2000.

Remarks. – Holthuis (1978) tentatively treated Caridina serratirostris serratirostris De Man, 1892 and C. s. celebensis as separate species mainly based on the characters of length of rostrum and stylocerite as the adult specimens that he was dealing with from Sumba could easily be assigned to one another. Yeo et al. (1999) followed Holthuis’s idea to recognize these two species, assigned all their Tioman ( Malaysia) specimens to C. celebensis . They also suggested that C. leptocarpa Liang & Zheng, 1988 from Fujian and Guangxi, southern China is most probably C. celebensis . Liang (2004: 321), however, pointed out that his material lacking an arthrobranch on the base of first pereiopod, and thus moved his species from Caridina to Paracaridina Liang & Guo, 1999 (in Liang, Guo & Tang, 1999), a genus only differs from Caridina by the lack of arthrobranch on first pereiopod. Re-examinations of types of C. serratirostris and C. celebensis show that the presence of an arthrobranch on the base of first pereiopod, although the size could be highly variable, is a good character to separate C. serratirostris from C. celebensis . Examination of specimens from Ryukyus and Pulau Tioman of Malaysia, however, show that previous characters used by Holthuis (1978) and Yeo et al. (1999) are not always reliable. Specimens with a rostrum reaching to or slightly beyond end of antennular peduncle are normally C. serratirostris , while those with shorter rostrum could be either one.

The present study shows that the size of the arthrobranch on the base of first pereiopod in C. serratirostris is higly variable, from very distinct to almost indiscernible, but is totally absent in C. celebensis . Obviously, the lack of arthrobranch on the first pereiopod of C. celebensis could be reasonably explained as a secondarily lost character, rather than as a primarily lacking character to indicate a different phylogenetic lineage. It should well be remained in the genus Caridina . This discovery questions the validity of some species of genera, or genera themselves, e.g. Parisia Holthuis, 1956 , Puteonator Gurney, 1987 , Paracaridina Liang & Guo, 1999 , etc., which were separated from Caridina and other related genera mainly by the absence of an arthrobranch on the base of first pereiopod. Furthermore, it challenges the validity of the subfamily Caridellinae Holthuis, 1986 , as well. Redefinitions on the basis of type material are necessary to validate the above mentioned taxa.

All the Tioman specimens here re-examined, though most of them with shorter rostrum, have an arthrobranch on the first pereiopod, thus, should be referred to C. serratirostris . In Ryukyus, specimens with short rostrum are mostly of C. celebensis , while those with long rostrum, almost all having arthrobranch on the fist pereiopod, are of C. serratirostris . Holthuis (1978: 42) commented that his Sumba specimens “In the branchial formula, pleopods and uropods hardly any difference is noticeable between the two species.” Apparently, he was dealing with only one species, C. serratirostris . Chace (1997) reported C. serratirostris from several localities of Philippines. According to his diagnosis and figures, his specimens have a “…rostrum not reaching as far as distal end of antennular peduncle.” It is impossible to assign his specimens to either species with certainty without a reexamination.

Distribution. – Japan, Philippines, Fiji, Malaysia, Indonesia and Madagascar.

Figures

Fig. 8. Caridina mindanao, new species, ovig. female, cl 3.8 mm, Mindanao, Philippines: A. telson; B, distal portion of telson; C, first pereiopod; D, second pereiopod; E, third pereiopod; F, dactylus of third pereiopod; G, fifth pereiopod; H, dactylus of fifth pereiopod; I, third maxilliped; J, diaeresis. Scale bars: A, C-E, G, I = 0.5 mm; B, F, H = 0.1 mm; J = 0.2 mm.

Fig.9. Caridina mindanao, new species, male, cl 3.3 mm, Mindanao, Philippines: A, first pereiopod; B, second pereiopod; C, third pereiopod; D, dactylus of third pereiopod; E, fifth pereiopod; F, dactylus of fifth pereiopod; G, male first pleopod; H, appendix masculina and appendix interna of male second pleopod; I, preanal carina. Scale bars: A-C, E, I = 0.5 mm; D, F = 0.1 mm; G, H = 0.2 mm.