Alpheus armillatus H. Milne Edwards, 1837

Anker, Arthur, 2012, Revision of the western Atlantic members of the Alpheus armillatus H. Milne Edwards, 1837 species complex (Decapoda, Alpheidae), with description of seven new species, Zootaxa 3386 (1), pp. 1-109 : 104-105

Key to the western Atlantic species of the Alpheus armillatus H. Milne Edwards, 1837 complex and A. viridari ( Armstrong, 1949)

1a. Rostral carina conspicuously flattening posteriorly, forming more or less V or U-shaped post-rostral plate markedly delimited from adjacent rostro-orbital furrows; pollex of major chela without triangular notch................................... 2

1b. Rostral carina gradually flattening posteriorly (posterior to eyes), not forming markedly delimited post-rostral plate; pollex of major chela with small triangular notch best visible in lateral view [fresh specimens: body with orange-brown reticulation, chelipeds brown with white blotches and spots, distal portion of major chela dactylus pink, see Fig. 66L ]................................................................................................... A. viridari ( Armstrong, 1949)

2a. Post-rostral plate abruptly delimited, with lateral margins clearly overhanging adjacent rostro-orbital furrows, forming deep longitudinal channel....................................................................................... 3

2b. Post-rostral plate more or less markedly delimited, with lateral margins not or only slightly overhanging adjacent rostro-orbital furrows, not forming deep longitudinal channel............................................................... 7

3a. Major chela plunger very short, with proximal height less than 0.5 length of distolateral margin; at most fist to second abdominal sternites with moderately developed median processes.......................................................... 4

3b. Major chela plunger long, stout, with distolateral margin equal or almost equal to proximal height; first to fourth abdominal sternites with very strong median processes..................................................................... 6

4a. First and second abdominal sternites with well-developed median process; plunger extremely short, its distal surface being almost a continuation of ventral margin of dactylus [fresh specimens: body orange with small pale-yellow spots, chelipeds yellow, usually with some purple distally, see Fig. 66E ]........................................... A. amarillo sp. nov.

4b. First and second abdominal sternites unarmed; plunger more pronounced, distinctly deviating from ventral margin of dactylus. ..................................................................................................... 5

5a. Post-rostral plate bulb-shaped, with lateral margins curving mesially posterior to the eyes [fresh specimens: body brownish orange with small pale-yellow spots, chelipeds orange-brown with grey and pale yellow areas, see Fig. 66G ].................................................................................................... A. tampensis sp. nov.

5b. Post-rostral plate V-shaped, with lateral margins straight, not curving mesially posterior to the eyes [fresh specimens: body pale greyish conspicuously speckled with small dark spots, chelipeds bluish-grey with pale yellow ares, see Fig. 66F ]................................................................................................ A. punctatus sp. nov.

6a. Thoracic sternum with strong processes at the base of each fourth pereiopod; post-rostral plate sloping rather abruptly into rostral carina; merus of major cheliped without spiniform setae; ventral shoulder of major chela with minute tubercles laterally [fresh

6b. Thoracic sternum without strong processes (at most bluntly protruding) at the base of each fourth pereiopod; post-rostral plate sloping rather gently into rostral carina; merus of major cheliped with small spiniform setae; ventral shoulder of major chela smooth laterally [fresh specimens: body with conspicuous brown, red-brown to greenish-bluish transverse bands, chelipeds brownish with white spots and blotches, antennular and antennal flagella blue, see Fig. 66A ]................................................................................................. A. armillatus H. Milne Edwards, 1837

7a. Ventromesial tooth of first article of antennular peduncle blunt; post-rostral plate broadly V-shaped [fresh specimens: body with conspicuous red-brown to brown-bluish transverse bands, chelipeds brownish-orange with white spots and blotches, antennular and antennal flagella yellow-orange, see Fig. 66B ]...................................... A. lancirostris Rankin, 1900

7b. Ventromesial tooth of first article of antennular peduncle with acute point; post-rostral plate narrowly V or intermediate V-U shaped............................................................................................... 8

8a. Second article of antennular peduncle about 1.5 times as long as wide [fresh specimens: body with conspicuous red to reddishbrown bands, chelipeds reddish-brown with white spots and blotches, see Fig. 66K ]..................... A. nuno sp. nov.

8b. Second article of antennular peduncle at least 2.0 times as long as wide............................................ 9

9a. Major chela with dactylus plunger relatively long, with proximal height more than 0.7 length of distolateral margin [fresh specimens: dactylus plunger whitish mesially]................................................................... 10

9b. Major chela with dactylus plunger relatively short, with proximal height at most 0.6 length of distolateral margin [fresh specimens: dactylus plunger orange mesially]................................................................... 11

10a. First and second abdominal sternite with strong median process in males; fifth pereiopod ischium with or without spiniform seta on ventrolateral surface [fresh specimens: body with diffuse, brown or reddish to greenish-brown transverse bands, second and fourth abdominal somite each with a black spot laterally, third somite with a small black spot dorsolaterally, chelipeds brownish with white spots and blotches, see Fig. 66H ].................................................... A. carlae sp. nov.

10b. First abdominal sternite with small median process, second abdominal sternite unarmed in males; fifth pereiopod ischium unarmed on ventrolateral surface [fresh specimens: body uniform brownish, pale yellow, reddish, or greenish, evenly speckled with minute spots, second, third and fourth abdominal somites without black spots, chelipeds greenish to brownish, major chela with two conspicuous whitish patches near ventral and dorsal notches, respectively, see Fig. 66D ]..................................................................................................... A. angulosus McClure, 2002

11a. First to fourth abdominal somites with strong median process in females; dactylus plunger of major chela with anterior angle> 90° [fresh specimens: body uniform red-brown to chocolate-brown, second and fourth abdominal somites each with a conspicuous black spot laterally, third somite always without spots, chelipeds brownish-grey, see Fig. 66I ]..... A. mathewsae sp. nov.

11b. First to fourth abdominal somites unarmed in females; dactylus plunger of major chela with anterior angle close to 90° [fresh specimens: body uniform reddish brown to dark brown, second and fourth abdominal somites each with a small black spot laterally, third somite often with inconspicuous spot dorsolaterally, chelipeds brownish-grey, see Fig. 66J ]... A. brasileiro sp. nov.

Figures

FIGURE 66. Colour patterns of 11 western Atlantic species of the Alpheus armillatus H. Milne Edwards, 1837 complex and A. viridari (Armstrong, 1949): A, A. armillatus H. Milne Edwards, 1837; B, A. lancirostris Rankin, 1900; C, A. verrilli (Schmitt, 1924); D, A. angulosus McClure, 2002; E, A. amarillo sp. nov.; F, A. punctatus sp. nov.; G, A. tampensis sp. nov.; H, A. carlae sp. nov.; I, A. mathewsae sp. nov.; J, A. brasileiro sp. nov.; K, A. nuno sp. nov.; L. A. viridari (Armstrong, 1949). All photographs by the author