Figuse 55. — Alpheus armiUatus Milne Edwards. A, an- 

 terior portion of body in dorsal view ; B, rostral region 

 in dorsal view with light showing from posterior ; C. 

 large chela in dorsal view ; A-C, 5 mm. indicated. 



maxilliped covered with long hairs distally, reach- 

 ing about to end of antennal peduncle. 

 * First legs strongly chelate, hairy, unequal. 

 Larger chela thick ; outer and inner margin deeply 

 notched near base of fingers; upper and lower 

 surfaces with irregular shallow grooves; dactyl 

 broad, heavy, curved, with large basal tooth. 

 Small chela slender; cutting edges of fingers 

 closely fitting, dactyl with a small tooth at base, 

 dactyl in males lacking setose crests and expanded 

 external surface characteristic of A. heterochaelis. 

 Second legs long, slender, weakly chelate, with 

 part of merus reaching beyond rostrum; carpus 

 subdivided with joints diminishing in length as 

 follows (numbered from proximal end) : 1, 2, 5, 

 3-4. Third to fifth legs with simple dactyls. 



Abdomen smooth, compressed. Telson with two 

 pairs of dorsal spines, iirst pair al one-third, 

 second al two-thirds Length; sides somewhat 



convergent distally, tip rounded, with a pair of 

 spines at each posterolateral corner, medial spine 

 twice length of outer spine. Uropodal exopod 

 with outer margin ending in a small spine flanked 

 medially by a larger spine. 



Measurements. — Length of body: ovigerous fe- 

 males, 31 to 38 mm. 



Color. — Body with dark gray or brown ground 

 color, crossed by nine conspicuous lunate or 

 elliptical spots or bands of translucent white equal 

 in width to intervening dark bands; carapace with 

 three white bands, third one at posterior margin; 

 abdomen with six bands, first blending with last 

 on carapace; abdominal bands usually whiter or 

 more clearly defined than bands on carapace; 

 abdomen often dark green with spots bordered by 

 line of orange; uropods and telson usually with 

 a broad crossband and sometimes tipped with 

 orange; chelae thickly speckled with dark gray, 

 whitish bands above, tipped with pale pink or 

 white; antennal peduncles grayish, flagella and 

 walking legs orange yellow banded with white 

 (Verrill, 1922). 



Habitat. — Under rocks and shells or in holes 

 in rocks; shallow water. 



Type locality. — "West Indies. 



Known range. — North Carolina, through West 

 Indies to Cananeia, Sao Paulo, Brazil; Bermuda 

 (Holthuis, 1956). 



Remarks. — This species closely resembles A. 

 heterochaelis, its similar sized and (in the Caro- 

 linas) much more abundant congener. Alpheus 

 armiUatus is named for its conspicuously banded 

 body, but in preserved material it can be dis- 

 tinguished from similar species by the distinctive 

 form of the rostrum and from ^4. heterochmlis 

 males by the lack of the specialized dactyl on the 

 small first chela. 



The species is rarely taken in the Beaufort 

 region of North Carolina. Hay and Shore ( 1918 ) 

 found males and females living in pairs under 

 rocks at Fort Macon. Ovigerous females are 

 known from only the first half of the annual 

 cycle: March, Panama : April, Venezuela: May, 

 Barbados; June, Florida and Brazil: August, 

 Bermuda. 



Pearse (1932b) reported encysted larvae of 

 Rhyncobothrius in viscera of .1. armiZlatus. 



Coonfield (1910) observed the chromatophore 

 system of this shrimp in one of the early studies 



CS 



FISH AND WILDLIFE SERVICE 



