Macrobrachium spinipes (Schenkel, 1902)

Shy, Jhy-Yun, Wowor, Daisy & Ng, Peter K. L., 2013, A new record of the giant freshwater prawn, Macrobrachium spinipes (Schenkel, 1902) (Crustacea: Decapoda: Palaemonidae) from Taiwan, with notes on its taxonomy, Zootaxa 3734 (1), pp. 45-55 : 46-52

Macrobrachium spinipes (Schenkel, 1902)

( Figs. 1A –B, 2A, 3A, 4, 5A–B)

Palaemon Rosenbergii De Man, 1879: 167 (Andai, New Guinea [ Papua], Indonesia).

Palaemon carcinus .—von Martens 1868: 34 (part).—De Man 1879: 165 (part).—Miers 1880: 382 (part).—Thallwitz 1892: 7, 15.—Schenkel 1902: 504.—Cowles 1914: 3, pl. 1, Fig. 1 (nec Cancer carcinus Linnaeus, 1758 ).

Palaemon carcinus Rosenbergii. —Ortmann 1891: 701.

Palaemon (Eupalaemon) carcinus .—De Man 1892: 421 (part); 1902: 475, 763 (part).—Nobili 1899: 236.—Roux 1928: 219 (nec Cancer carcinus Linnaeus, 1758 ).

Palaemon (Eupalaemon) Rosenbergii. —Nobili 1899: 236.

Palaemon spinipes Schenkel, 1902: 501 , pl. 9, Fig. 7 (nec Palaemon spinipes Desmarest, 1817 ) (Kema, Minahasa, northern Sulawesi).

Palaemon (Eupalaemon) carcinus var. rosenbergii .—Roux 1917: 595; 1921: 587; 1923: 4; 1927: 321; 1933: 344.

Macrobrachium rosenbergii .—Holthuis 1950: 111, Fig. 25 (part).—Johnson 1960: 261 (part).—Hedgecock et al. 1979: 873 (part).—Lindenfelser 1984: 195 (part).—Chace & Bruce 1993: 36, Fig. 15 (part). — Mather & De Bruyn 2003: 4 (part).— De Bruyn et al. 2004a: 251 (part); 2004b: 3515.—Short 2004: 44, Figs. 16–18, 36L, M.—Chand et al. 2005: 308.—De Bruyn & Mather 2007: 4295.—Wowor & Ng 2007: 324.

Macrobrachium rosenbergi (sic).—Riek 1951: 361, Fig. 12.

Macrobrachium rosenbergii rosenbergii .—Johnson 1973: 277.—Holthuis 1995: 148; 2000: 16, Fig. 2.2.—Cai & Ng 2001: 674.—Holthuis & Ng 2009: 15, Fig. 2.2.

Macrobrachium wallacei Wowor & Ng, 2008: 288, 291.—ICZN 2010: 259.

Macrobrachium spinipes .—Ng & Wowor 2011: 66.—De Grave & Fransen 2011: 330.

Material examined. Taiwan — Ilan County: 1 male, cl 30.9 mm (NTOU F20653), coll. J.-Y. Shy, 9 Sep 2010; 1 female, cl 43.2 mm (NTOU F20256-1), coll. J.-Y. Shy & H.-T. Lai, 11 Oct 1985; 1 female, cl 53.2 mm (NTOU F20618), coll. J.-Y. Shy, 6 Sep 2008; 1 female, cl 49.1 mm (NTOU F20454), coll. J.-Y. Shy, 11 Oct 2008; 1 female, cl 40.9 mm (NTOU F20455), Lo-tung, coll. J.-Y. Shy, 17 Oct 2008; 1 female, cl 38.2 mm (NTOU F20628), coll. J.- Y. Shy, 23 Aug 2009; 1 male, cl 29.8 mm (NTOU F20629), coll. J.-Y. Shy, 23 Aug 2009; 1 female, cl 52.4 mm (NTOU F20642), coll. J.-Y. Shy, 23 Aug 2009; 1 male, cl 35.7 mm (NTOU F20646), coll. J.-Y. Shy, 9 Sep 2010; 1 female, cl 41.2 mm (NTOU F20654), coll. J.-Y. Shy, 23 Oct 2010; 1 male, cl 70.05 mm (NTOU F20661), coll. J.-Y. Shy, 22 Sep 2011; Pingtung County: 1 male, cl 16.3 mm (NTOU F20260), coll. J.-Y. Shy, 15 Jul 1989.

Comparative material. Macrobrachium rosenbergii : Taiwan — Ilan County: 1 male, cl 30.1 mm (NTOU F20256-2), coll. J.-Y. Shy & H.-T. Lai, 11 Oct 1985; Tainan County: 1 male, cl 37.8 mm (NTOU F20257-1), coll. H.-P. Yu, 20 Sep 1982; 1 male, cl 37.8 mm, 1 ovigerous female, cl 25.5mm (NTOU F20584), coll. H.-P. Yu, 20 Sep 1982; Pingtung County: 2 males, cl 20.9–21.8mm (NTOU F20582), coll. J.-G. Hwang, Mar 1997; 2 females, cl 29.6–31.1mm (NTOU F20583), coll. M.-H. Wu, Mar 1997; Penghu County: 1 female, cl 35.3mm (NTOU F20655), coll. J.-Y. Shy, 20 Jan 2011; 1 male, cl 37.3mm (NTOU F20656), coll. J.-Y. Shy, 20 Jan 2011; 1 male, cl 40.95 mm (NTOU F20664), coll. J.-Y. Shy, 12 Aug 2011. Indonesia — 1 male, cl 17.9 mm (NTOU F20581), coll. T.-Y. Chan, Jan 1997. See Wowor & Ng (2007) for complete list of material (as M. dacqueti ) from its entire natural distribution. Macrobrachium spinipes : Indonesia — Papua: 1 male, cl 46.6 mm (MZB Cru 243), Pionier Bivak, Mamberamo River, coll. W. C. Van Heurn, 14 Dec 1920; 1 male, cl 53.3 mm (MZB Cru 245), Pionier Bivak, Mamberamo River, coll. W. C. Van Heurn, 18 Dec 1920; 1 ovigerous female, cl 57.2 mm (MZB Cru 1309), Mamberamo River, Mamberamo Hilir District, Jayapura Regency, coll. A. Munandar, 22 Sep 1985; 1 male, cl 25.5 mm, 4 females, cl 28.1–45.6 mm, 1 ovigerous female, cl 41.6 mm (MZB Cru 2620), Apom River, Atsj District, Asmat Regency, coll. A. Suyanto & A. Saim, 16 Sep 2009; 1 male, cl 25.9 mm, 3 females, cl 27.2–32.7 mm (MZB Cru 1171), Ajkwa River, Mimika Timur District, coll. S. N. Priyono, 3 Jul 1985; 1 male, cl 56.6 mm (MZB Cru 3202), Ajkwa River, Mimika Regency, coll. PT Freeport Indonesia, 5 Feb 2007; 2 males, cl 21.5–59.6 mm, 2 females, cl 31.3–47.7 mm, 1 ovigerous female, cl 32.4 mm (MZB Cru 3203), Kamora River, Mimika Regency, coll. PT Freeport Indonesia, 21 Feb 2007; 1 male, cl 46.9 mm (MZN Cru 3204), Wai Rabiai River, Waigeo Island, Raja Ampat Regency, coll. D. Wowor, 3 Jun 2007. Mollucas: 1 female, cl 23.0 mm, 2 ovigerous females, cl 36.7– 37.0 mm (MZB Cru 1317), Wayapu River, Mako Village, Buru Utara Timur, Buru Island, coll. A. S. Adhikerana & D. Hardjono, 9 Oct 1982. Sulawesi: 1 male, cl 44.9 mm, 1 ovigerous female, cl 53.4 mm (MZB Cru 736), Likupang, Minahasa Regency, North Sulawesi, coll. May 1979; 1 male, cl 80.9 mm (MZB Cru 1083), Jennemaeja River, Pattedong, Luwu Regency, South Sulawesi, coll. M. Siluba, 22 Apr 1984.

Diagnosis. Rostrum slender, about one-third distal part extending beyond scaphocerite, tip curved upwards, base of rostrum with low to very low crest; rostral formula 3 + 9–11/9–11, dorsal teeth unequally spaced, usually with wide gap near posterior and anterior ends. Second pereiopods long, subcylindrical with carpus extending beyond scaphocerite, carpus about 1.3 times as long as merus, equal in size, similar in form, covered by large spines and interspersed spinules except dactylus covered by pubescence. T4 armed with median projection and posterior submedian plate in form of short low ridge. Preanal carina present. Mobile mesial spine of exopod of uropod smaller than distolateral tooth. Eggs small, numerous.

Live color of Taiwan Macrobrachium spinipes . In large individuals (cl about ≥ 50mm), the body is greenishblue, the carapace has several thin longitudinal bluish-white stripes and dotted lines. All pleural condyles have orange spots of different color intensity except for the condyles at the joints of the third and the fourth pleura which are colorless. The condyles at the joints of the first and the second pleura and the second and the third pleura have light orange or orange spots, while the condyles at the joints of the fourth and the fifth pleura as well as the fifth and the sixth pleura always have prominent orange color spots. The lower margin of the pleura has a white border in mature females. The inner flagellum of the antennule is blue, while the outer flagellum of the antennule and the flagellum of the antenna are pale blue at the base, gradually becoming darker blue distally. All pereiopods are pale blue, except for the base of the fingers of the second pereiopod which is bright orange ( Fig. 1A ). In small individuals (cl about ≤ 35mm), the body is greenish-yellow. The carapace has thick and thin longitudinal dark brown stripes with a red band in the middle of the rostrum, and the abdomen is mottled dark brown. The inner flagellum of the antennule is dark blue to blue, while the outer flagellum of the antennule and the flagellum of the antenna are yellow at the base, gradually becoming pale blue and finally dark blue at the distal end ( Fig. 1 B).

Distribution in Taiwan. Ilan County (northeast) and Pingtung County (southwest).

Remarks. With regards to M. spinipes , a total of 12 specimens were purchased and examined. This includes two specimens (1 female, NTOU F20256-1; 1 male, NTOU F20260) which had originally been identified as “ M. rosenbergii ” in old collections from Ilan and Pingtung counties. Thus far, M. spinipes has only been reported from between the Tropic of Cancer (23°50’N) and the Tropic of Capricorn (23°50’S). The most northerly record for M. spinipes previously was Calumpit in Bulacan, Central Luzon in the Philippines (14°54’59”N) (Eguia et al. 2009), while the most southern record was at Leichhardt Falls in Queensland, Australia (18°16’56”S) (Short 2004). In Taiwan, M. spinipes has been found in Lo-Tung, Ilan County, at 24°41’0”N, the most northern record for the species to date. Its distribution in the Philippines and Taiwan might be associated with the Kuroshio Current which affects the dispersal of all amphidromous Macrobrachium species with planktotrophic larvae found in eastern Taiwan and adjacent northern and southern regions (Chen et al. 2009, 2010).

Superficially, M. spinipes closely resembles M. rosenbergii . However, juveniles and adults can easily be distinguished by two main characters: 1) the upper margin of M. spinipes has a relatively low rostral crest ( Fig. 2A ) which is higer in M. rosenbergii ( Fig. 2 B); and 2) the inner and outer flagella of the antennules and the flagella of the antenna are blue to greenish-blue in live adult M. spinipes ; but in M. rosenbergii , the outer flagellum of the antennule and the flagella of the antenna are light blue to light yellow in smaller individuals, and the inner flagellum of the antennule is blue to brown or reddish and the outer flagellum of the antennule and the flagella of the antenna are light brown to yellow ( Fig. 1 C). As has been discussed by Wowor & Ng (2007), the spination of the adult second pereipods of these two species is also different; M. spinipes has both large spines and interspersed spinules ( Fig. 3 A), while M. rosenbergii has only large spines ( Fig. 3 B). However, this character does not work in smaller specimens. Interestingly, the spination of the second pereipods of the Taiwanese M. spinipes is relatively weaker compared to those from Indonesian Papua as described and figured by Wowor & Ng (2007), although it is still stronger than that in M. rosenbergii . Similarly, the posterior submedian plate of T4 of the Taiwanese M. spinipes is in the form of a short low ridge, while that of the Indonesian Papua specimen (a female of similar size) is relatively longer with a more prominent ridge. Another difference is that the pleural condyles of the Taiwanese specimens of M. spinipes have orange spots; while those of young Papuan and Philippines have bright red dots (see Wowor & Ng, 2007).

Subadult M. spinipes from Indonesian Papua (male, cl 46.9 mm, MZB Cru 3204) and Sulawesi ( Fig. 4A ) have a similar color pattern, i.e. with having several dark brown longitudinal stripes on the carapace, a red rostrum and the abdomen is mottled dark brown. Subadults from Cebu, Philippines, have dark green longitudinal stripes on the carapace, a reddish rostrum and dark green mottling on the abdomen ( Fig. 5 ). In Taiwan, subadults are blue with bluish-white longitudinal stripes on the carapace, a grayish-blue rostrum and white mottling on the abdomen ( Fig. 1A ). In Taiwan, Liao (1979) reported on the presence of a “golden stripe” form in Wu-Long River near Tong-Gung town in Pingtung County between 1971 and 1973 (only a monochrome photograph was provided), and this was the form also cultured in Chia-Yi County between 1972 and 1976. However, this form has apparently become extinct from southern Taiwan due to heavy pollution downstream of Wu-Long River and nearby drainages. There is also no longer any culture of these prawns in Chia-Yi County (SJY, personal observation). How this “golden stripe” form is different from the typical form with bluish-white longitudinal stripes is not clear. It may be a matter of color interpretation or perhaps the form reported by Liao (1979) was just more intensely colored. In any case, the differences observed and discussed above are not very significant and can be explained by variation. This is especially considering that the Taiwanese population of M. spinipes is at the edge of the known distribution of the species.

Juvenile specimens of M. spinipes are quite consistent in coloration, with distinct colors and chromatophore patterns: the rostrum is red, the body is transparent with several black longitudinal stripes on the carapace and there is black mottling on the abdomen ( Fig. 4 B). As a result of its bright colors and attractive chromatophore pattern, it is sold in the aquarium trade in Europe, but infrequently, with perhaps one shipment per year from Sulawesi; the price being about US $10 for one specimen (W. Klotz, personal communication).

In summary, M. spinipes is recorded for the first time from Taiwan, although it appears to be rather rare. It extends the natural distribution of this species northwards, and across the Tropic of Cancer . It can be distinguished from the similar M. rosenbergii by several morphological characters as well as antennal and antennular flagella coloration. Young specimens of M. spinipes are collected for the aquarium trade because of their attractive coloration, while the adults are important in aquaculture and fisheries.

Figures

FIGURE 3. Male chelae. A, Macrobrachium spinipes, male, cl 70.05 mm (NTOU F 20661); B, Macrobrachium rosenbergii, male, cl 40.95 mm (NTOU F 20664). Specimens from Taiwan.

FIGURE 5. Specimens from Cebu, Philippines. A, B, Macrobrachium spinipes, subadults; C, Macrobrachium rosenbergii, subadult (specimens not collected). Photograph by Homer de Dios.

FIGURE 1. A, Macrobrachium spinipes, female, cl 53.2 mm (NTOU F 20618); B, Macrobrachium spinipes, male, cl 30.9 mm (NTOU F 20653); C, Macrobrachium rosenbergii, male, cl 37.3 mm (NTOU F 20656). All specimens from Taiwan.

FIGURE 2. A, Macrobrachium spinipes, female, cl 53.2 mm (NTOU F 20618); B, Macrobrachium rosenbergii, male, cl 37.3 mm (NTOU F 20656). Specimens from Taiwan.

FIGURE 4. A, Macrobrachium spinipes, subadult female, Sulawesi (specimen not collected); B, Macrobrachium spinipes, juvenile, about 3 cm total length same individual as the subadult female from Sulawesi (specimen not collected). Photographs by Werner Klotz.