Alpheus formosus Gibbes. Striped snapping shrimp 

 Figure 52 



Alpheus formosus Gibbes, 1850, p. 196. — Verrill, 1922, p. 84. 

 text-figs. 5d, 6a ; pi. 20. fig. 3 ; pi. 23, figs. 5 a, b ; pi. 29, figs. 4. 

 a-u ; pi. 25, figs. 6-6a. 



Crangon formosus: Hay and Shore, 191S, p. 384, pi. 26. fig. 

 5— Schmitt. 1935a, p. 144. 



Recognition characters. — Rostrum beginning at 

 posterior line of eyes and reaching about to second 

 article of antennular peduncle; flat above; mar- 

 gins concave at base but regularly convergent 

 anteriorly and with scattered stiff hairs; tip 

 rounded, often bearing two or three minute spines. 

 Carapace half length of abdomen, compressed, 

 not grooved; orbital hoods each with an acute, 

 anteriorly directed spine much shorter than ros- 

 trum; anterior margin emarginate below orbital 

 hoods. Eyes completely covered by carapace. 

 Antennular peduncles with scalelike stylocerite, 

 slender tip reaching slightly beyond basal article; 

 second article twice length of third; inner flagel- 

 lum filiform, outer flagellum thick proximally, 

 filiform distally. Antenna longer than body; 



Figure 52. -Alpheus formosus Gibbes. A. anterior pari 

  if bod; in dorsal view ; B, outer surface of large chela : 

 5 nun. indicated. 



antennal scale with strong apical spine reaching 

 to or beyond tip of antennular peduncle, spine 

 separated from and exceeding lamella; a weak 

 spine (basicerite) below near base of scale. Third 

 maxillipeds with terminal joint hairy; slightly 

 exceeding antennal peduncle. 



First legs strongly chelate, very unequal. 

 Larger leg compressed, smooth above and un- 

 notched along margins; immovable finger acute, 

 incurved at tip, shorter than stout and gradually 

 arched, blunt dactyl; carpus short, convex above, 

 with a distal tooth; merus with an acute distal 

 spine. Smaller chela much more slender, long, 

 and smooth, inner surface with a stout spine over- 

 hanging base of dactyl; immovable finger nearly 

 straight, slender, somewhat turned up near tip; 

 dactyl about half length of hand, nearly straight 

 to about middle, then gently arched to tip, hairs 

 arising from a nearly straight groove below ridge 

 on both sides; inner surfaces of fingers with a 

 slender groove and carina ; fingers shutting closely. 

 Second pair of legs slender; weakly chelate; 

 carpus subdivided, with joints diminishing in 

 length as follows (numbered from proximal end) : 

 1, 5, 2, 3—1. Third to fifth legs with simple 

 dactyls. 



Telson with two pairs of dorsal spines at about 

 one-third and two-thirds length; posterolateral 

 corners with a pair of spines, medial spine much 

 longer than lateral, distal margin with long hairs. 

 Uropodal exopods with lateral margin ending in 

 a black movable spine between two fixed spines; 

 black spine remaining amber colored after long 

 preservation. 



Measurements. — Length of body: ovigerous fe- 

 males, 17 to 35 mm. 



Color. — Color pattern conspicuous and charac- 

 teristic; ground color yellowish or greenish brown 

 finely speckled with orange; a narrow light stripe 

 along middorsal line extending from distal end 

 of antennular peduncle to base of telson, line 

 light orange anteriorly merging into yellowish 

 green and finally gray posteriorly, a brown stripe 

 on each side dorsolaterally and below this another 

 stripe of white, or colors similar to dorsal stripe, 

 along each side followed by a stripe of light red- 

 dish brown and still another stripe of blue border- 

 ing abdomen; chelae greenish brown with orange 

 icd fingers; antennules, antennae, and walking 



til 



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