Alpheus verrilli (Schmitt, 1924)

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: 22-31

publication ID

http://doi.org/ 10.11646/zootaxa.3386.1.1

persistent identifier

http://treatment.plazi.org/id/03A41310-FF85-7D50-16FC-FA631B74FBE5

treatment provided by

Felipe

scientific name

Alpheus verrilli (Schmitt, 1924)
status

 

Alpheus verrilli (Schmitt, 1924)  

( Figures 14, 15, 16A–G, 17, 18, 64C, 65C, 66C, 67C)

Crangon verrilli Schmitt 1924a: 77   , pl. 2, figs. 7–10 (part., holotype only).

Alpheus cf. verrilli   — Mathews & Anker 2009: 277.

Alpheus armillatus   or Crangon armillatus   (not H. Milne Edwards, 1837)— Verrill 1922: 76 (part., specimen from Colón, Panama referred to as A. armillatus   var., “No 735b”).

(?) Alpheus armillatus   (not H. Milne Edwards, 1837)— Amaral et al. 2010: 246.

Not Crangon verrilli Schmitt 1924a: 77   (part., paratype = A. armillatus   ) [tentative assignment, see text].

Type material. Barbados: holotype: ov. female (cl 15.0), USNM 68786 View Materials , “ Barbados-Antigua Expedition from the University of Iowa ”, in empty shell of Strombus   , 29.05.1918   .

Additional material. Panama: 1 male (cl 15.7), OUMNH. ZC. 2011-06-028, Bocas del Toro   , Isla Bastimentos, off Salt Creek, degraded reef with sand patches, rocks, rubble, and some living corals, 3–4 m, leg. A. Anker, 31.03.2008 [fcn 08-017]; 1 male (cl 9.0), RMNH D54811 View Materials , Bocas del Toro   , Isla Colón, Punta Caracol, sand flat with rubble, sponges, clumps of Halimeda   , 1–2 m, leg. A. Anker, 30.03.2008 [fcn 08-004]   . Belize: 1 ov. female

(cl 12.0), OUMNH. ZC. 2009-01-0034, Carrie Bow Cay, Twin Cays, N side, 16°50.074’N 88°06.467’W, cracking of coral rubble, 1–1.5 m, leg. S. De Grave, 24.02.2009 [fcn CBC-173]. USA: 1 male (cl 13.4), MNHN-IU-2010   -

channel”, ocean side, mixed hard and sand bottom with algae, coral rubble and loggerhead sponges, 1 m, leg. A. Anker, 06.09.2008 [fcn 08-277]; 1 male (cl 15.0), FLMNH UF Arthropoda 26043, Florida Keys , Long Key, LONF1 tower dive site west of Florida Keys Marine Laboratory, sand and seagrass bottom with rubble, about 2 m, G. Paulay et al., 02.05.2010 [fcn KEYS-0762]; 1 male (cl 18.4), FLMNH UF Arthropoda 19757, Florida Keys, Woman Key, grass and sand bottom, in conch shell, 0.5–2 m, leg. A. Anker, A. Bemis, S. McPherson, 10.06.2009 [fcn KEYS-0428]; 1 ov. female (cl 18.2), FLMNH UF Arthropoda 19765, same collection data   [fcn KEYS-0439]. Brazil: 1 ov. female (cl 16.8), MZUSP 5338 View Materials   , Rio de Janeiro, Ilha Grande , Praia do Furado, leg. G. S. de Melo, 20.07.1966; 2 males (cl 15.5, 16.1), 1 ov. female (cl 17.4), MZUSP 5340 View Materials , same collection data   .

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 broadly U-shaped postrostral plate, its margins clearly overhanging rostro-orbital furrows; post-rostral plate situated distinctly above and sloping rather abruptly into narrow rostral carina. Antennule with stylocerite acute distally, slightly overreaching distal margin of first article; ventromesial carina of first article with low tooth bearing acute point on anterior margin; second article about twice as long as wide. Antenna with basicerite armed with stout distolateral tooth; scaphocerite with broadly concave lateral margin, strong distolateral tooth reaching well beyond relatively narrow blade; carpocerite exceeding scaphocerite blade but not (or very slightly) distolateral tooth, reaching beyond 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 smooth, without stout spiniform setae distally, with strong distomesial tooth; palm with dorsal shoulder rounded, sloping into adjacent transverse groove almost vertically, not overhanging groove; ventral shoulder broadly rounded, not projecting, with numerous minute tubercles ventrolaterally; fingers more than half-length of palm; pollex without oblique ridge mesially; dactylus plunger large, stout, distally somewhat truncate, proximal height about 0.8 length of distolateral margin, anterior angle superior to 90°. Female major cheliped slightly smaller than male major cheliped, with smaller, less stouter chela. Male minor cheliped with merus very stout, distodorsal margin blunt, ventromesial margin without spiniform setae, with small distomesial tooth; chela rather stout, palm with length-height ratio about 1.7; palm without longitudinal depressions, with deep sinus on ventral margin delimited by feeble shoulder laterally; fingers about as long as palm, stout, simple, non-balaeniceps, with sharp cutting edges. Female minor cheliped generally similar to male minor cheliped, more slender; palm without or with very faint ventral sinus. Second pereiopod slender, with first two carpal articles longest, first about 1.2 length of second. Third and fourth pereiopods similar, stout; ischium with spiniform seta ventrolaterally; merus slightly more than four 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 with or without spiniform seta in both sexes. Sternum at the base of fourth pereiopods with conspicuously projecting, slender, subacute processes. First to fourth abdominal sternites in males each with median process between bases of pleopods, processes usually stronger and sharper on first and second sternites, weaker and blunter on third and fourth sternites; first to fourth sternites in females each with strong, subacute, median process. First to fourth pleopods with ventrolateral margin of protopod bearing row of widely spaced, short spiniform setae in males, with one or more rows of longer and stronger spiniform setae in large females; male second pleopod with appendix masculina not exceeding 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. 14, 15, 16A–G).

Variation. The size and proportions of the major cheliped may vary between the males and the females, and younger and older individuals. The sternal processes at the base of the fourth pereiopods are less projecting in the largest of the Florida specimens, a male from Woman Key (FLMNH UF Arthropoda 19757), as well as in all Brazilian specimens (see below). The presence of a spiniform seta on the fifth pereiopod ischium appears to be variable: it can be well-developed ( Fig. 14G), reduced to a trace, or absent (e.g., most Brazilian specimens). The development of spiniform setae on the protopods of female pleopods is also variable: some females have them organised in simple or double rows; others don't have them at all.

Colour pattern. Body overall pale brown-red, orange-reddish or greenish-brown, uner higher magnification with a multitude of reddish chromatophores forming complex and intercalating chains, not grouped into transverse bands on the abdomen, however, with very narrow colourless areas at anterior and posterior margin of each somite, forming narrow white bands clearly separating adjacent somites; pleura with a more conspicuous pattern of brownreddish triangles or bands and larger white areas; post-rostral plate brown-red on margins; antennular and antennal flagella pale greenish-yellow to pale orange; chelipeds with mostly whitish ischium and merus, latter with some bluish-brown pattern distally and dorsally; carpus green-brown with white spots; mesial face of major chela with background varying from red-brown to greenish-brown, with large pale-greenish or bluish spots and occasionally larger patches, including on dactylus and pollex; distal portion of dactylus and pollex pinkish; minor chela greenish phores (Figs. 17, 18A); younger individuals with more distinct transverse banding on abdomen (Fig. 18B, C). Brazilian specimens overall more greenish, and with more intense-orange antennular and antennal flagella; eggs yellow-orange (Fig. 18D). matophores; telson and uropods mostly red-brown, uropodal exopod paler, with some golden-yellow chromatophores (Figs. 17, 18A); younger individuals with more distinct transverse banding on abdomen (Fig. 18B, C). Brazilian specimens overall more greenish, with more intense orange antennular and antennal flagella; eggs yellow-orange (Fig. 18D).

Type locality. Barbados.

Distribution. Caribbean Sea: Belize (Carrie Bow Cay), Panama (Colón, Bocas del Toro), Barbados; southern Florida: Florida Keys; Brazil: Rio de Janeiro, São Paulo (see map in Fig. 70).

Ecology. Shallow reefs and adjacent rubble flats at a depth range of 0–4 m; typically on mixed sand-rock bottoms, e.g., rubble fields with abundant algal coverage, sand flats with some seagrass cover and scattered large rocks or rubble; usually in burrows under large rocks or coral rubble, occasionally also in dead conch shells ( Schmitt 1924a); typically in male-female pairs.

Remarks. Alpheus verrilli   is morphologically very close to A. armillatus   and the eastern Pacific A. hyeyoungae   , the three species forming Clade 5 in Mathews & Anker (2009, fig. 4). In the western Atlantic, A. verrilli   can be easily confused with A. armillatus   , from which it can be most conveniently separated by the presence of a ventrally projecting, sternal process at the base of each fourth pereiopod (cf. Figs. 5A, B, 16A–D, G). Other, more subtle features distinguishing A. verrilli   from A. armillatus   are the somewhat shorter, higher, more U-shaped, and more abruptly sloping post-rostral plate; the absence of spiniform setae on the ventromesial margin of the merus of the major and minor chelipeds (usually present in A. armillatus   ); the more numerous tubercles on the ventral shoulder of the major chela (less numerous or absent in A. armillatus   ); and the more truncate dactylus plunger of the major chela (cf. Figs. 3G, 15F). The difference in the post-rostral plate may be difficult to appreciate without a direct sideby-side comparison of specimens of both species, and in addition, this difference seems to be blurred in larger specimens of A. armillatus   and A. verrilli   ( Figs. 2B, 14B).

The colour patterns of A. verrilli   and A. armillatus   , although generally similar, differ in a few details. Fullgrown adults of A. verrilli   have a very diagnostic colour pattern (type BA 7 in Mathews & Anker 2009, fig. 2M), which differs from that of A. armillatus   by the much less conspicuous abdominal banding and pale-greenish (not blue or bluish) antennular and antennal flagella (Figs. 17, 18A-C). Younger individuals of A. verrilli   are more distinctly banded, but can still be distinguished from A. armillatus   by the colour of the antennular and antennal flagella (Fig. 18B, C). In addition, in both adults and juveniles of A. verrilli   , the major chela is usually speckled with bluish-whitish spots of about the same size (Figs. 17, 18), whereas in most individuals of A. armillatus   , the major chela is covered with irregular white spots, often fused to form larger white blotches ( Figs. 6–8). Alpheus verrilli   is also genetically distinct from A. armillatus   , as revealed by the analysis of 16S gene fragment ( Mathews & Anker 2009).

Alpheus verrilli   is more distantly related to A. lancirostris   , from which it can be separated by the same morphological criteria as A. armillatus   (see above) combined with the diagnostic sternal processes at the bases of the fourth pereiopods.

The paratype of A. verrilli   (USNM 57938) differs from the holotype (USNM 68786) in the absence of strong sternal processes at the bases of the fourth pereiopods ( Fig. 16G, H), a condition observed in A. armillatus   ( Fig. 5A) and A. lancirostris   . In all mophological features combined the paratype of A. verrilli   actually agrees with A. armillatus   and is therefore tentatively included in the material of the latter species (see above).

The status of the Brazilian specimens, here provisionally assigned to A. verrilli   , requires confirmation. They are morphologically very similar to the specimens from the Caribbean-Florida region, perhaps with the exception of the generally less developed sternal processes between the fourth pereiopods. The colour pattern of an ovigerous female from São Paulo (Fig. 18D, specimen not examined) is generally similar to that of the specimens from Panama and Florida Keys (Figs. 17, 18A), although it has a more intense green body colour and much brighter orange antennular and antennal flagella. A genetic (COI) comparison between the Brazilian and Caribbean-Florida populations of A. verrilli   is required to find out whether these slight differences are of any taxonomic or phylogeographic significance.

GenBank accession numbers. Panama: FJ528575 View Materials (MyHC)   , FJ528482 View Materials (16S) [ RMNH D54811 View Materials ]   .

ZC

Zoological Collection, University of Vienna

RMNH

National Museum of Natural History, Naturalis

FLMNH

Florida Museum of Natural History

UF

Florida Museum of Natural History- Zoology, Paleontology and Paleobotany

Kingdom

Animalia

Phylum

Arthropoda

Class

Malacostraca

Order

Decapoda

Family

Alpheidae

Genus

Alpheus

Loc

Alpheus verrilli (Schmitt, 1924)

Anker, Arthur 2012
2012
Loc

Alpheus cf. verrilli

Mathews, L. M. & Anker, A. 2009: 277
2009
Loc

Crangon verrilli

Schmitt, W. L. 1924: 77
1924
Loc

Crangon verrilli

Schmitt, W. L. 1924: 77
1924
Loc

Alpheus armillatus

Verrill, A. E. 1922: 76
1922