Synalpheus iphinoe de Man, 1909

Wang, Yan-Rong & Sha, Zhong-Li, 2015, A review of the genus Synalpheus (Crustacea: Decapoda: Caridea: Alpheidae) from China seas, Zoological Systematics 40 (4), pp. 357-435 : 386-390

3.2.13 Synalpheus iphinoe de Man, 1909 * ( Figs 20–22 )

Synalpheus iphinoë de Man, 1909 . Tijdschr. ned. dierk. Verecn., 11(2): 116.

Synalpheus jedanensis de Man, 1909 . Tijdschr. ned. dierk. Verecn., 11(2): 117.

Material examined. CL 3.1–5.9 mm, TL 6.7–11.9 mm. (MBM 270449), 52 ovigerous ♀, 10 immature specimens, Tonkin Gulf (Beibu Gulf), Sta. 6277, depth 35 m, 19 October 1960, coll. Shou-Peng Shen; (MBM 270447), 30 ovigerous ♀, 17♂, Tonkin Gulf (Beibu Gulf), Sta. 6277, depth 13.5 m, 9 July 1960, coll. Zhen-Gang Fan; (MBM 270595), 3 ovigerous ♀, 6♂, 14 immature specimens, Tonkin Gulf (Beibu Gulf), Sta. 6277, depth 31.3 m, 11 May 1960, coll. Zhen-Gang Fan; (MBM 270584), 3♂, Tonkin Gulf (Beibu Gulf), Sta. 6283, depth 25 m, 11 February 1960, coll. Zhen-Gang Fan, Ruan; (MBM 270199), 1♂, Tonkin Gulf (Beibu Gulf), Sta. 6282, depth 28 m, 11 February 1960, coll. Zhen-Gang Fan; (MBM 270598), 1♂, Tonkin Gulf (Beibu Gulf), Sta. 6276, depth 30 m, 5 December 1959, coll. Zhen-Gang Fan; (MBM 270239), 1 ovigerous ♀, 3♂, Tonkin Gulf (Beibu Gulf), Sta. 6284, depth 18.5 m, 18 May 1960, coll. Zhen-Gang Fan; (MBM 270581), 3 ovigerous ♀, 4♂, Tonkin Gulf (Beibu Gulf), Sta. 6237, depth 50.5 m, 14 April 1960, coll. Xiu-Bin Fang; (MBM 270194), 1♂, Tonkin Gulf (Beibu Gulf), Sta. 7502, depth 32 m, 15 January 1962, coll. Fu-Zeng Sun; (MBM 270585), 2♂, Tonkin Gulf (Beibu Gulf), Sta. 6267, depth 32 m, 5 November 1960, coll. Bao-Lin Zhang; (MBM 270439), 4 ovigerous ♀, 1♂, Tonkin Gulf (Beibu Gulf), Sta. 6280, depth 27 m, 5 December 1959, coll. Xiu-Tong Ma; (MBM 270451), 1 ovigerous ♀, 1♂, Tonkin Gulf (Beibu Gulf), Sta. 6261, depth 42 m, 4 December 1959, coll. Zhen-Gang Fan; (MBM 270527), 17 specimens, Tonkin Gulf (Beibu Gulf), Sta. 7603, depth 44 m, 18 August 1962, coll. Fu-Zeng Sun; (MBM 270539), 3♀ (two ovigerous), 2♂, Tonkin Gulf (Beibu Gulf), Sta. 7602, depth 26m, 18 August 1962; (MBM 270583), 1 ovigerous ♀, 3♂, Tonkin Gulf (Beibu Gulf), Sta. 6269, depth 30 m, 6 November 1960, coll. Bao-Lin Zhang; (MBM 270597), 2 ovigerous ♀, 7♂, Tonkin Gulf (Beibu Gulf), Sta. 6282, depth 28m, 9 July 1960, coll. Zhen-Gang Fan, Ruan; (MBM 270583), 4♀ (three ovigerous), 27♂, Tonkin Gulf (Beibu Gulf), Sta. 6277, depth 35 m, 11 February 1960, coll. Zhen-Gang Fan; (MBM 270579), 11♀ (ten ovigerous), 9♂, Tonkin Gulf (Beibu Gulf), Sta. 6276, depth 29 m, 6 November 1960; (MBM 270126), 49♂, Tonkin Gulf (Beibu Gulf), Sta. 6277, depth 35 m, 9 March 1960, coll. Zhen-Gang Fan, Feng-Shan Xu; (MBM 158690),1 ovigerous ♀, 2♂, Nansha Islands, Sta. 55, depth 46 m, 8 June 1960; (MBM 158364), 1♂, Nansha Islands, Sta. 64, depth 44 m, 9 June 1960; (MBM 270445), 23 ovigerous ♀, 27♂, Tonkin Gulf (Beibu Gulf), Sta. 6277, depth 35 m, 19 October 1960, coll. Shou-Peng Shen; (MBM 270582), 2 ovigerous ♀, 4♂, Tonkin Gulf (Beibu Gulf), Sta. 6249, depth 31 m, 7 November 1960, coll. Bao-Lin Zhang; (MBM 158846), 1♂, Nansha Islands, Sta. Z 13, depth 50 m, 28 April 1986; (MBM 270440), 1♂, Tonkin Gulf (Beibu Gulf), Sta. 7604, depth 58 m, 12 January 1962, coll. Fu-Zeng Sun; (MBM 270377), 1♂, Tonkin Gulf (Beibu Gulf), Sta. 6265, depth 66.3 m, 14 July 1960, coll. Zhen-Gang Fan.

Description. Carapace smooth, glabrous; conical rostrum about 3 times as long as wide at base, acute tip overreaching middle of first segment of antennular peduncle; orbital hoods slightly longer than rostrum, diverge slightly outward, both rostrum and orbital hoods distinctly curved upturned at tips; pterygostomial corner produced into acute angle; cardiac notch well developed.

Telson about 1.3 times as long as wide at base; dorsal surface with two pairs of spines, inserted approximately at 2/5 and 3/5 length of telson; posterior margin strongly produced, fringed with long setae, posterolateral angle each with two pairs of spines, lateral about 1/3 length of mesial, posterolateral margins each produced into acute small tooth, but distinctly shorter than lateral spines. Media-dorsal of endopod bearing dense setae, coves all length of it.

Eyes concealed in dorsal view, slightly exposed in lateral view.

Antennular peduncle slender, with distally acute stylocerite, latter reaching about 1/4 length of second segment of antennular peduncle; second segment about 1.7 times as long as wide at base; visible part of first segment longer than second and more than twice as long as third. Basicerite with acute distodorsal tooth, less 1/2 length of distolateral tooth, latter distinctly shorter than stylocerite, not reaching end of first segment of antennular peduncle; carpocerite overreaching end of third segment of antennular peduncle; scaphocerite blade moderately narrow, reaching about 1/2 length of third segment of antennular peduncle, lateral spine developed, overreaching end of antennular peduncle, hardly shorter than carpocerite.

Third maxilliped far beyond antennular peduncle and carpocerite when extended; antepenultimate segment longest; penultimate segment about 1.7 times as long as wide at base; tip of ultimate segment bearing crown of moderately long six spine-like setae, with transverse rows of long setae along ventral margin.

Major cheliped with short, stout ischium; merus about 2.6 times as long as wide at base, superodistal margin with one acute triangular tooth; carpus cup-shaped, with setae distodorsally; palm about 2.3 times as long as dactylus, distodorsal of palm with one strong acute projecting, slightly upturned at base and curved to dactylus at tip; dactylus slightly longer than pollex.

Minor chela with merus about 3 times as long as wide at base, superodistal margin with one acute triangular tooth; carpus cup-shaped, proportionally longer that of major cheliped; palm about twice as long as fingers; dactylus and pollex tapering, distal single tooth.

Second pereiopod with ischium shorter than merus; carpus five-segmented, segment ratio subequal to 7: 1: 1: 1: 2.7, with first segment distinctly longer than sum of last four segment; dorsal margin of palm convex; fingers about 1.3 times as long as palm. Third pereiopod moderately slender; merus longer than propodus, about 4 times as long as wide at base, ventral margin with 10 moderately large spines; carpus less 1/2 length of merus, with dorsal margin extended into an obtuse tooth, ventral margin with one distal spine; propodus with 11 spines along ventral margin plus one distal pair of spines near dactylus; dactylus about 1/5 length of propodus, slightly curved to propodus, biunguiculate, extensor tooth about 1/3 length of flexor tooth, notch between extensor and flexor tooth V-shaped, flexor tooth much wider at base than extensor tooth. Fourth pereiopod generally similar to third; merus slightly longer than propodus, ventral margin with five moderately large spines; ventral margin of propodus with 8 spines plus distal one pair spines. Fifth pereiopod similar to third and fourth pereiopods, but ventral margin of carpus without one distal spine; merus slightly shorter than propodus, ventral margin without spines; ventral margin of propodus with 6 transversal rows of spine-like setae and three spines.

Remarks. Synalpheus iphinoe and S. jedanensis were originally described by de Man (1909) based on 7 and 6 specimens, respectively. They are morphologically very similar to S. neomeris , and can be separated from each other by the minor chela. The morphological characters used by de Man to separate the three species are: setae on the frontal teeth; the proportions of three segments of the antennular peduncle; the proportions of the small chela; the number of spines on the merus of the third pereiopods; the posterolateral margins each produced to spines or not. However, some of these characters were variable in alpheids, so Banner & Banner (1985) put S. iphinoe and S. jedanensis under the name S. iphinoe on the basis of page priority. De Grave & Fransen (2011) listed S. jedanensis as a valid species, we think it is unwise.

Banner & Banner (1985) presented “ S. iphinoe be separated from S. neomeris on basis of small size, the probable heavier small chela, and the upturned tips to the frontal teeth”. The present materials (over 200 specimens) have following differences from S. neomeris : the total length of the specimens varied from 6.5 mm to 13.2 mm, contrasted to the longest specimen of S. neomeris (about 30 mm); the fingers of the minor chela in S. neomeris subequal to or slightly shorter than palm, in S. iphinoe the ratio of fingers / palm length of minor chela about 0.5; the frontal teeth of part of our specimens were upturned at tips. The present specimens are slightly variable in the shape of the rostrum ( Figs 22c–d ), but this variation is not enough to separate them into two species. Additionally, three of our specimens are aberrant at the frontal teeth: lost the rostrum ( Fig. 21g ), or the right orbital hood bearing three teeth at tip ( Fig. 22a ), or the right orbital hoods of the other specimen reduced ( Fig. 22b ). Those differences might cause by effects of the environment.

Distribution. Tonkin Gulf (Beibu Gulf), South China Sea; Sapeh-Strait; Southern Molo-Strait; Banda-anchorage; Roma Island; East cost of Aru Islands.

Figures

Fig. 20. Synalpheus iphinoe de Man, 1909, female (cl 5.7mm) (MBM 158695). a–b. Frontal region. a. Dorsal. b. Lateral. c–d. Third maxilliped. c. Dorsal. d. Tip, ventral. e–g. Major cheliped (right). e. Mesial. f. Chela, lateral. g. Merus, lateral. h–i. Minor cheliped (left). h. Lateral. i. Chela, lateral. j. Second pereiopod, lateral. k–l. Third pereiopod. k. Lateral. l. Distal propodus and dactylus, lateral. Scale bars: a–c, e–k=1 mm; d, l=0.5mm.

Fig. 21. Synalpheus iphinoe de Man, 1909, female (cl 5.7mm) (MBM 158695). a–b. Fourth pereiopod. a. Lateral. b. Distal propodus and dactylus, lateral. c. Fifth pereiopod. d. Second pleopod. e. Abdomen, lateral. f. Telson and uropod, dorsal. g. Female (cl 5.9mm) (MBM 270539) frontal region, dorsal. Scale bars: b=0.5mm; a, c–g =1mm.

Fig. 22. Synalpheus iphinoe de Man, 1909, male (cl 4.9 mm) (MBM 158690). a. Frontal region, dorsal. b–d. Frontal region, male. b. Dorsal (cl 4.5mm) (MBM 270126). c. Dorsal (cl 5.1 mm) (MBM 270126). d. Lateral (cl 5.1mm) (MBM 270126). Scale bars= 1 mm.