Alpheus lancirostris Rankin, 1900

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 : 18-21

publication ID	https://doi.org/ 10.11646/zootaxa.3386.1.1
persistent identifier	https://treatment.plazi.org/id/03A41310-FF81-7D5A-16FC-FBB51ADBF83A
treatment provided by	Felipe
scientific name	Alpheus lancirostris Rankin, 1900
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Alpheus lancirostris Rankin, 1900 View in CoL

( Figures 9–13 View FIGURE 9 View FIGURE 10 View FIGURE 11 View FIGURE 12 View FIGURE 13 , 64B View FIGURE 64 , 65B View FIGURE 65 , 66B View FIGURE 66 , 67B View FIGURE 67 )

Alpheus lancirostris Rankin 1900: 541 View in CoL , pl. 18, fig. 5.

Alpheus armillatus View in CoL (not H. Milne Edwards, 1837)— Zimmer 1913: 401, figs. K 1 -T 1 (part.?); (?) Boone 1930: 168, pl. 60; Hazlett 1962: 82; Hazlett & Winn 1962: 26; Sterrer 1986: 325, text-pl. 105, pl. 9, fig. 5.

Alpheus armillatus View in CoL or Crangon armillatus (not H. Milne Edwards, 1837)— Verrill 1922: 76, pl. 48, figs. 2-2n (part., material from Bermuda).

Alpheus cf. armillatus View in CoL B— Mathews & Anker 2009: 277.

Material examined. Bermuda: 2 males (cl 10.3, 11.5), 1 female (cl 9.8), USNM 1160395 About USNM , Hungry Bay , leg. J. Gosling, 07-09 (“ July — Sept ”), year unknown, no further data [access #38875, 1 male dissected] . Mexico: 1 male (cl 11.5), OUMNH. ZC. 2011-06-027, Yucatan, Quintana Roo, Mahahual, backreef platform with segrass and some rocks and coral rubble, 0.5–1 m, leg. A. Anker, J. Duarte-Gutiérrez, 06.07.2010 [fcn MAH-023]; 1 male (cl 10.2), 1 ov. female (cl 10.6), MNHN-IU-2010-4068, southern Gulf of Mexico off Yucatan, Arrecife Alacranes, 22°23'19.30"N, 89°40'47.80"W, rock-sand bottom, under rocks/rubble, 0.3 m, leg. J. Duarte-Gutiérrez, 31.07.2009 [fcn JD-004]; 1 male (cl 10.5), 1 ov. female (cl 10.6), OUMNH. ZC. 2012-03-0004, southern Gulf of GoogleMaps Mexico off Yucatan, Arrecife Alacranes, 22°21'29.50"N, 89°39'37.00", sand-rubble bottom, inside dead shell of Strombus gigas , 1.5 m, leg. J. Duarte-Gutiérrez, 03.08.2009 [fcn JD-027]; 1 male (cl 8.2), OUMNH. ZC. 2011-06-046, southern Gulf of Mexico off Yucatan, Arrecife Alacranes , Isla Perez, sand, rocks, rubble, 0.5–2 m, coll. N. Simões et al., 06.11.2008 [fcn ALA-043 = 08-249] . Belize: 1 male (cl 8.4), 1 ov. female (cl 8.9), OUMNH. ZC. 2009-01-0032, Carrie Bow Cay , 16°48.141’N 88°04.905’W, intertidal flat with Porites , inside dead conch, leg. S. De Grave, 24.02.2009 [fcn CBC-168] GoogleMaps . Panama: 1 male (cl 8.9), RMNH D54810, San Blas Islands , Isla Diablo (small uninhabited island near Cartí), reef flat with rubble, 1–2 m, under rocks and rubble, leg. A. Anker, I.N. Marin, 23.05.2007 [fcn 07-188] . Venezuela: 1 female (cl 12.7), MNHN-IU-2010-4069 , Isla Cubagua, sand flat with abundant rubble and seagrass, 1.5 m, leg. A. Anker, 26.11.2003 [fcn 03-021, dissected] .

Diagnosis. Rostrum straight, exceeding half-length of first article of antennular peduncle; area posterior to rostral carina flattened, abruptly delimited from adjacent deep rostro-orbital furrows, forming subtriangular, V-shaped post-rostral plate, its margins not or very slightly overhanging rostro-orbital furrows; post-rostral plate situated above and usually gently, sometimes abruptly sloping into moderately broad rostral carina. Antennule with stylocerite acute distally, barely reaching distal margin of first article; ventromesial carina of first article with broad unarmed tooth; second article slightly more than twice as long as wide. Antenna with basicerite armed with strong distolateral tooth; scaphocerite with slightly concave lateral margin, strong distolateral tooth reaching well beyond relatively narrow blade; carpocerite exceeding scaphocerite blade, always reaching distolateral tooth, and usually exceeding end of antennular peduncles. Third maxilliped with ultimate article as broad as penultimate, tapering distally. Major cheliped edwardsii - type (see under A. armillatus ). Male major cheliped with merus very stout, distodorsal margin ending bluntly, ventromesial margin somewhat rugose, with row of stout spiniform setae distally and strong distomesial tooth; palm with dorsal shoulder rounded, sloping into adjacent transverse groove with angle almost vertically, not overhanging groove; ventral shoulder broadly rounded, not projecting, smooth laterally; fingers more than half-length of palm; pollex without oblique ridge mesially; dactylus plunger large, stout, proximal height about 0.8 length of distolateral margin, anterior angle slightly more than 90°. Female major cheliped somewhat smaller than male major cheliped, with chela weaker and with more or less different proportions. Male minor cheliped with merus stout, distodorsal margin blunt, ventromesial margin with row of spiniform setae and sharp distomesial tooth; chela moderately stout, palm with length-height ratio about 2.0; palm with very slight longitudinal depression laterally, with deep sinus on ventral margin fringed by small ventral shoulder; fingers about as long palm, simple, non-balaeniceps, with sharp cutting edges. Female minor cheliped generally similar to male minor cheliped, usually more slender; palm without or with very faint ventral shoulder. Second pereiopod slender, with first two carpal articles longest, first about 1.4 length of second. Third and fourth pereiopods similar, moderately stout; ischium with spiniform seta ventrolaterally; merus about five times as long as wide; propodus with stout spiniform setae, sometimes inserted in pairs, along ventral margin, incuding one pair adjacent to dactylus; dactylus about 0.4 length of propodus, simple, conical. Fifth pereiopod much more slender than third and fourth; ischium without spiniform seta in both males and females. Sternum at the base of fourth pereiopods without conspicuously projecting, slender processes. First and second abdominal sternites unarmed in both males and females. First to fourth pleopods without spiniform setae on ventrolateral margin of protopod; male second pleopod with appendix masculina shorter than appendix interna, densely covered with stiff setae, especially on apex. Uropod with exopod and endopod broadly rounded; exopod with sinuous diaeresis and stout distolateral spiniform seta; endopod with row of small spiniform setae on distal margin. Telson broad, slightly tapering posteriorly; dorsal surface with two pairs of spiniform setae inserted far from lateral margins; posterior margin broadly rounded, with row of small spiniform setae; posterolateral angles each with two spiniform setae, mesial much longer than lateral ( Figs. 9–11 View FIGURE 9 View FIGURE 10 View FIGURE 11 ).

Variation. Like A. armillatus and several other species of the A. armillatus complex, A. lancirostris is sexually dimorphic in the size and proportions of the major cheliped between the males and the females. In larger individuals, the post-rostral plate is situated distinctly above the anterior rostral carina and is sloping more abruptly than in smaller individuals.

Size range. The examined specimens range from 8.9 to 11.5 mm cl in males, and from 9.8 to 10.6 mm cl in females.

Colour pattern. Background opaque greysh-white; carapace with two very broad, transverse, brown or greybrown bands; each abdominal somite with a broad transverse, brown or dark grey-brown band; post-rostral plate dark brown-grey on margins; antennular and antennal flagella orange-yellow; chelipeds with ischium, merus and carpus marbled with brown; mesial face of major chela marbled with brown and whitish and with numerous interconnecting white spots, pale yellowish area usually present on proximal half; dactylus and pollex brown and whitespotted except for hyaline-pink distal areas; mesial face of minor chela brown with some white marbling and spotting; second to fifth pereiopods yellow; telson and uropods mostly brown or dark-grey, with some white or paleorange areas ( Figs. 12 View FIGURE 12 , 13 View FIGURE 13 ); younger individuals with larger white band across proximal portion of major chela palm ( Fig. 13A, B View FIGURE 13 ), this band being later replaced by a pale beige patch ( Fig. 13C, D View FIGURE 13 ). See also colour descriptions in Rankin (1900), Verrill (1922, as A. armillatus ) and Boone (1930, as A. armillatus ), and colour photograph in

Type locality. Bermuda .

Distribution. Bermuda; southern Gulf of Mexico (Alacranes Reef off northern Yucatan); Caribbean Sea: Mexico (Cozumel Island), Belize (Carrie Bow Cay), Panama (San Blas Islands), Venezuela (Isla Cubagua); Jamaica (Port Antonio) ( Rankin 1900; Verrill 1922; present study) (see map in Fig 70 View FIGURE 70 and remarks below).

Ecology. Intertidal and shallow subtidal reef and other hard-bottom habitats at a depth range of 0–2 m, possibly deeper; on mixed sand-rubble bottoms, sometimes near Thalassia beds or mangroves; under large rocks or pieces of coral rubble, occasionally in sponges or dead shells of Strombus ; typically in male-female pairs.

Remarks. Alpheus lancirostris forms a distinctive, purely western Atlantic lineage within the A. armillatus complex, Clade 6 in Mathews & Anker (2009, fig. 4). This species is distinguishable from A. armillatus by the broadly triangular post-rostral plate gently sloping into the rostral carina (vs. U-shaped and more markedly sloping in A. armillatus ); the absence of strong median processes on the first and second abdominal sternites in both males (vs. armed with a spiniform seta in A. armillatus ). The colour pattern of A. lancirostris (type BA 3 in Mathews & Anker 2009, fig. 2G, J) is unique, combining the broad, dark, greenish or red-brownish, transverse bands on the carapace and abdomen with the yellow-orange antennular and antennal flagella ( Figs. 12 View FIGURE 12 , 13 View FIGURE 13 ).

Alpheus lancirostris has been reported several times as A. armillatus in the past. Zimmer (1913) reported A. armillatus from four localities, viz. Florida’s Tortugas (Bird Key Reef), Barbados, St. Thomas, and Jamaica (Kingston). Most of Zimmer’s drawings, however, apparently refer to A. lancirostris , based on the diagnostic shape of the post-rostral plate ( Fig. 1C View FIGURE 1 ). Zimmer (1913) did not indicate from which specimen he made his drawings and therefore the locality of the illustrated specimen remains unknown. Verrill (1922) erroneously synonimised A. lancirostris with A. armillatus , applying the latter name to all his Bermuda specimens. Boone’s (1930) specimen of A. armillatus from about 3.6 m off Port Antonio, Jamaica, most likely refers to A. lancirostris based on the very detailed description of the colour pattern.

GenBank accession numbers. Bermuda: FJ528572 View Materials , FJ528573 View Materials (MyHC) , DQ682892 View Materials , DQ682893 View Materials (16S) , FJ528547 View Materials , FJ528548 View Materials ( COI) [not deposited] ; Venezuela: FJ528574 View Materials (MyHC) , FJ528480 View Materials (16S) FJ528546 View Materials ( COI) [MNHN-IU-2010-4069] .

view; C, major cheliped, ischium, merus and carpus, mesial view; D, major chela dactylus, lateral view; E, minor chela, mesial view; F, same, lateral view; G, minor cheliped, ischium, merus and carpus, mesial view. Scale bar as indicated.