Synalpheus townsendi Coutière, 1909

Salazar, Margarita Hermoso, Wicksten, Mary & Morrone, Juan J., 2005, Redescriptions and taxonomic notes on species of the Synalpheus townsendi Coutière, 1909 complex (Decapoda: Caridea: Alpheidae), Zootaxa 1027 (1), pp. 1-26 : 6-12

Synalpheus townsendi Coutière, 1909

Figures 1–4

Synalpheus townsendi Coutière, 1909: 32 , fig. 14.— Chace 1972: 104.— Christoffersen 1979: 352 (including extensive synonymy).— Williams 1984: 106, fig. 73.

? Synalpheus townsendi — Pequegnat and Ray 1973: 249, figs. 53d, 55.

Synalpheus townsendi productus Coutière, 1909: 32 , fig. 15.

Material examined: GULF OF MEXICO: Sonnier Bank (28°20’N, 90°27’W), 25–60 m, submersible vehicle (sub), 27 Sept. 1977, cruise 77G10­2, 5 spec. ( TCWC 2­6817 ) . Diaphus Bank (28°05’N, 90°41’W), 92 m, remote­operated vehicle ( ROV) , 29 Sept. 2003, Ronald Brown sta. 42, 1 spec. ( TCWC 2­8875 ) . Fishnet Bank (28°10’N, 91°49’W), 70 m, sub, 13 Oct. 1978, sta. 78G9III3A, 1 spec. ( TCWC 2­7864 ) . Sidner Bank (27° 59’N, 92° 22’W), 68–103 m, sub, 17 Oct. 1978, sta. 78G9 IIID120 , 1 spec. ( TCWC 2­7924 ) . Eighteen Fathom Bank (27° 58’N, 92° 36’W), 46 m, sub, 28 Sept. 1977, sta. 77G10­2, 3 spec. ( TCWC 2­6818 ) . Twenty­eight Fathom Bank (27° 55’N, 93° 27’W), 132 m, box core?, 3 Aug. 1976, sta. 4F, 1 spec. ( TCWC 2­7861 ) . East Flower Gardens Bank (27° 55’N, 93° 36’W), 16–120 m, sub, 24 Oct. 1978, sta. 78G9 IIID134 , 1 spec. ( TCWC 2­7865 ) . West Flower Garden Bank (27° 53’N, 93° 49’W), 23 m, hand, 12 Jan. 1972, sta. 770110­IV, 1 spec. ( TCWC 2­2443 ) . Coffee Lump (28° 3’N, 93° 54’W), 60–67 m, sub, 11 Oct. 1978, sta. 78G9 IIID1 , 1 spec. ( TCWC 2­7862 ) . Stetson Bank (28° 10’N 94° 17’W), 3 lots as follows: 50 m, grab, 6 Aug. 1976, sta. STB­4D, 1 spec. ( TCWC 2­7971 ) ; 22 m, scuba, 1 March 2000, M.K. Wicksten, collector, 1 spec., ( TCWC 2­8720 ) ; 24 m, scuba, 2 Sept. 2003, M. Wicksten, coll., 5 spec. ( TCWC 2­8865 ) . Little Sister Bank (28° 51’N, 94° 15’W), 86 m, trawl, 10 Oct. 1978, sta. 78G9III­4, 1 spec. ( TCWC 2­7866 ) . Islas de Lobos (21°27’N, 94°14’W), 7.6 m, 6 Oct. 1972, hand, IL sta. 1, 3 spec. ( TCWC 2­2134 , 2­2135 , 2­8750 ) ; 7.6 m, 8 Oct. 1972, hand, IL sta. 2, 5 spec. ( TCWC 2­2128 , 2­2129 , 2­2130 , 2 ­ 213.1 , 2­2132 ) ; 7.6 m, 8 Oct. 1972, hand, IL sta. 3, 5 spec. ( TCWC 2­2127 , 2­2133 ) ; 9.8 m, hand, 10 Oct. 1972, IL sta. 6, 1 spec. ( TCWC 2­2126 ) . FLORIDA (Atlantic): Pepper State Park , off St. Lucie County, 5.7 m, among Oculina coral, 12 Sept. 1977, J.K. Reed, 2 spec. (1 ov.) ( LACM) .

Description

Rostrum slender, straight, 2–4 times longer than wide, reaching from end of first segment of antennular peduncle to 0.3 times length of second segment, overreaching length of orbital teeth; anterior margin between orbital teeth and base of rostrum almost straight. Orbital hoods triangular, at least as long as wide; orbital teeth slender and acute. Ventral rostral process short. Pterygostomial angle of carapace produced. Carapace margin ventrally convex.

Antennular peduncle short and stout, 5 times as long as wide; visible part of first segment almost as long as combined lengths of segments 2–3, approximately 1.3 times length of second segment; second segment 1.3 times length of third segment. Stylocerite reaching almost to 0.6 times length of second segment. Lateral antennular flagellum thicker at base than mesial flagellum. Basicerite without dorsal tooth, but small tubercle or tooth may be present at end of dorsal obtuse angle, lateral tooth reaching 0.7–1.0 times length of first segment of antennular peduncle. Tooth of scaphocerite exceeding blade by length of third segment of antennular peduncle, reaching to or beyond end of antennular peduncle and carpocerite; blade well developed, 5.6 times as long as wide, with rounded distal margin. Carpocerite 4.2 times as long as wide, exceeding antennular peduncle by 0.5 times length of third segment.

Apex of third maxilliped with five strong spines; ultimate segment 3.5 times length of penultimate segment.

Ischium of major cheliped 1.5 times as long as wide. Merus twice as long as wide, bearing hooked tooth at distal end above articulation with carpus. Carpus short, 1.9 times as long as wide, cup­shaped. Chela 2.2 times as long as wide, palm 3.1 times as long as

fingers, smooth, approximately 3.7 times as long as wide, with blunt to sharp tooth on distal margin above articulation with dactylus; fixed finger with two blunt teeth, dactylus evenly rounded and without tufts of setae along margin.

Ischium of minor cheliped slightly shorter than wide. Merus 3.2 times as long as wide, ventral margin convex, dorsal margin with sharp angle at distal end above articulation with carpus. Carpus approximately as long as wide. Palm smooth, 2.2 times as long as wide, convex, 1.5 times as long as fingers; fingers evenly curved, with few setae.

Ischium of second pereopod twice as long as wide, 0.8 times length of merus. Merus 5.8 times as long as wide, 1.1 times as long as carpus. Carpus slender, with five segments having ratios of lengths from first to fifth as follows: 6:1:1:1:2. Chela slender, shorter than first segment of carpus, palm 0.9 times length of fingers, fingers straight and bearing tufts of setae.

Third to fifth pereopods gradually decreasing in size. Third pereopod with ischium 3.5 times as long as wide, 0.4 times length of merus, without spine. Merus 5–5.2 times as long as wide, more than twice length of carpus and without spines. Carpus short, 0.4 times length of propodus, without spines. Propodus shorter than merus, 2.9 times length of dactylus, with row of 8–14 spines (usually 9–12) on flexor margin. Dactylus slightly curved, ending in two ungui approximately equal in width but with flexor unguis about 0.3 times length of extensor unguis. Fourth and fifth pereopods similar but shorter. Fifth pereopod with 8 tufts of short setae as well as row of spines on flexor margin.

Pleuron of first abdominal somite of female rounded; of male, with small sharp posteroventral point, partially covered by pleuron of second abdominal somite; pleura of somites 2–3 rounded, those of 4 and 5 subrectangular in female, sharply pointed at ventral margin in male; those of sixth somite acuminate. First pleopod with endopod 0.3 times length of exopod. Second pleopod with appendix interna. Telson shorter than uropods, 1.3 times as long as wide, widest at proximal end, tapering gradually to rounded apex, with 2 pairs of dorsal spines: first pair inserted at 0.6 times length, second at 0.7 times length; distolateral margin ending in sharp tooth; posterior margin with two distolateral spines, lateral spine about half length of mesial spine. Uropods rounded on posterior margin, exopod with two lateral teeth at diaresis and spine between them.

Carapace length to 4.8 mm.

Color in life.— Red, dactylus of major chela dark green. Under a microscope, the shrimp has small red chromatophores against a translucent background. Hay and Shore (1918) described S. townsendi as light pellucid red, the large chela changing to green on the fingers.

Type locality.— Cape San Blas , Florida (29°14’00”N, 84°29’15”W) .

Habitat.— In the Gulf of Mexico, S. townsendi was collected among coral rubble, sponges or algal nodules. It also has been collected among sea grasses, algae, rocks, shells and tubes of polychaetes ( Christoffersen, 1979).

Geographic distribution and depth range.— Off Beaufort , North Carolina, U.S.A. to Rio de Janeiro, Brazil ; Gulf of Mexico , Caribbean, Bermuda ; intertidal to 132 m.

Remarks.— Specimens of S. townsendi show variation. The basicerite may be unarmed or bear a tiny tooth on the dorsal margin. Although illustrations of S. townsendi show a sharp tooth above the articulation of the palm of the major chela with the dactylus, this tooth may be absent, especially among the largest specimens. The shape of the abdominal pleura of somites 4 and 5 is sexually dimorphic. The length of the rostrum also varies, from as long as the first segment of the antennular peduncle to 0.3 times the length of the second segment. The distol­lateral tooth of the scaphocerite equals or surpasses the length of the antennular peduncle.

Figures

FIGURE 1. Synalpheus townsendi Coutière, 1909. A, frontal region of typical specimen in dorsal view. B, frontal region of specimen with elongate rostrum. C, D, telson and uropods. E, F, detail of posterior region of telson. A, C, E, TCWC 2­7863; B, D, E, TCWC 2­7920.

FIGURE 2. Synalpheus townsendi. A, carapace, frontal region and third maxilliped. B, ventral rostral process. C, abdomen. TCWC 2­7863 (specimen A).

FIGURE 3. Synalpheus townsendi. A, major cheliped, lateral view. B, major cheliped, mesial view. C, minor cheliped. D, second pereopod. TCWC 2­7863 (specimen C).

FIGURE 4. Synalpheus townsendi. A, third pereopod. B, fourth pereopod. C, fifth pereopod. D, second pleopod. TCWC 2­8720.