Alpheus wonkimi, Anker, Arthur & Pachelle, Paulo P. G., 2013

Anker, Arthur & Pachelle, Paulo P. G., 2013, Re-examination of the eastern Pacific and Atlantic material of Alpheus malleator Dana, 1852, with the description of Alpheus wonkimi sp. nov. (Crustacea, Decapoda, Alpheidae), Zootaxa 3637 (4), pp. 412-431 : 422-428

Alpheus wonkimi sp. nov.

( Figs. 7–10 , 11 I, J)

Alpheus malleator — Nobili 1901: 2; Rathbun 1902: 288; Sivertsen 1933: 4; Abele 1975: 72; Rodríguez de la Cruz 1977: 28; Brusca 1980: 252; Wicksten 1983: 43; Banner & Banner 1984: 42; Hendrickx & Wicksten 1987: 16; Kim & Abele 1988: 31, fig. 12; Wicksten & Hendrickx 1992: 5; Lemaitre & Alvarez-Leon 1992: 42; Wicksten 1993: 152; Hickman & Zimmermann 2000: 40; Wicksten & Hendrickx 2003: 64; Hendrickx & Hermoso-Salazar 2005: 433, fig. 1D (map); McClure 2005: 146, fig. 16; Lazarus-Agudelo & Cantera-Kintz 2007: 228 (not A. malleator Dana, 1852 ). Crangon malleator — Rathbun 1910: 607 (not A. malleator Dana, 1852 ).

Alpheus cf. malleator — Hurt et al. 2008: 516 et seq.

Type material: Panama: holotype: male (cl 11.8 mm), MNHN-IU-2010-7925, Pacific coast, Río Mar, lower part of predominantly rocky intertidal, low tide, in rock crevices near water edge, leg. A. Anker, J. Jara, E. Gomez, 3 March 2006 [fcn 06-266]; paratypes: 1 male (cl 8.2 mm), USNM, same collection data as for the holotype [fcn 06- 265]; 1 male (cl 9.7 mm), 1 female (cl 8.3 mm), RMNH.D.55154, Pacific coast, Río Mar, lower part of predominantly rocky intertidal, low tide, in rock crevices near water edge, leg. A. Anker, J. Jara, 19 April 2007 [fcn 07-120A, 07-120B]; 1 ov. female (cl 9.3 mm), OUMNH.ZC. 2010-01-0072, Pacific coast, Río Mar, El Higo, intertidal, rock conglomerate, leg. M. Torchin, 20.02.2007 [fcn 07-080]; 1 male (cl 11.9 mm), 1 ov. female (cl 10.2 mm), MNHN-IU-2010-7926, Pacific coast, Río Mar, rocky intertidal, leg. N. Knowlton et al., 20 Feb. 1992 [fcn C- 361, C-362].

Additional material: Panama: 1 male (cl 11.8 mm), OUMNH.ZC. 2007-07-0145, Pacific coast, Las Perlas Islands, Isla Contadora, rocky intertidal, low tide, in rock crevices near water edge, leg. A. Anker, C. Hurt, E. Gomez, E. Tóth, J. Jara, 31 March 2006 [fcn 06-366]; 1 female (cl 9.2 mm), RMNH.D.55155, same collection data as for the previous specimen [fcn 06-371]. Ecuador: 1 male (cl 14.6 mm), MNHN-IU-2010-4195, locality not specified, collector unknown, donated by A. Crosnier in 1979.

Description. For full description and illustrations of A. wonkimi sp. nov. see Kim & Abele (1988, as A. malleator ); additional illustrations are provided in Figs. 7–10 , 11 I, J. For separation of A. wonkimi sp. nov. from A. malleator see remarks below.

Variation. As in the previous species, the frontal margin of the carapace is variable in the width and shape of the post-rostral plate, the configuration (size, shape and direction) of adrostral teeth ( Figs. 7 A, 8A, 11I, J), and the size and proportions of the chelipeds, especially the major chela ( Figs. 7 D, 8B, C, 9, 10; see also Kim & Abele 1988: fig.12e, f.).

Colour pattern. Body ground colour variable from purple-brown to greenish or reddish-brown; carapace with broad, whitish, transverse band and numerous irregular patches and spots, many interconnected; rostrum dark purple-, greenish- or reddish-brown; orbital hoods, flanks and anterolateral areas of carapace mostly colourless; abdomen with narrow, irregular, white, transverse bands on each somite, some bands broken into rhomboid-shaped patches, bands continuing on pleura and splitting into two large white areas (usually two per pleuron: anterior and posterior); major and minor chelipeds brownish to brown-orange, with larger pale-yellow areas mesially, some tubercles dark brown, others marked by pale spots; dactylus of major chela grey-brown centrally, pinkish dorsally and distally; pollex of major chela mostly dark brown; adhesive disks contrasting whitish; fingers of minor chela dark brown-green; second pereiopods and walking legs reddish; antennular and antennal flagella pale brownyellowish to brown-greenish; tail fan purple-, greenish- or reddish-brown, without spots, diaeresis darker brown, spiniform seta of uropodal exopod brown, somewhat paler distally; pleopods reddish-brown ( Figs. 9. 10 ); see also colour photograph in Hickman & Zimmermann (2000).

Etymology. The new species is named after Prof. Won Kim (Seoul National University, Korea) for his important contribution to the taxonomy of the eastern Pacific members of the genus Alpheus (Kim & Abele 1988) .

Type locality. Río Mar, Pacific coast of Panama.

Distribution. Eastern Pacific: Mexico (Baja California, Sinaloa, Nayarit, Jalisco); El Salvador (Acajutla); Costa Rica (Golfo de Nicoya); Panama (Río Mar, Las Perlas Islands); Colombia (Bahía Málaga, Isla Malpelo); Ecuador (Bahía Santa Elena, Galapagos) (Nobili 1901; Rathbun 1902; Wicksten 1983; Kim & Abele 1988; Wicksten & Hendrickx 2003; present study).

Ecology. Lower intertidal of exposed rocky shores, near water edge at extreme low tides, deep inside rock crevices, possibly rock-boring or at least capable of enlarging natural cavities; at some localities, e.g., around Las Perlas Islands, sharing rock crevice microhabitat with Alpheus saxidomus Holthuis, 1980 and A. utriensis Ramos & von Prahl, 1989.

Remarks. Alpheus wonkimi sp. nov. can be separated morphologically from its Atlantic sister species, A. malleator , apparently by only one character. In A. malleator , the distolateral spiniform seta of the uropodal exopod is stout and wide at its base, especially in males (length/width ratio 2.9–3.7, measured in four individuals), and is black, sometimes with a pale-brown tip ( Fig. 1 I, J, M). In A. wonkimi sp. nov., this spiniform seta is more slender, relatively narrower at its base (length/width ratio 4.3–5.5, measured in three individuals) and is dark brown or tancoloured ( Fig. 7 K, P, Q). The brown or black colour of the uropodal spiniform seta usually persists for decades in alcohol-preserved specimens, but may fade or bleach completely in some very old or inadequately preserved specimens (e.g., in one male of A. wonkimi sp. nov. from Ecuador and in one female of A. malleator from Tobago). The two species can also be distinguished by the barcoding fragment of the COI gene sequence (Williams et al. 2001; Hurt et al. 2008). In addition, they are geographically separated from each other by the Isthmus of Panama.

The frontal region of the carapace of both A. malleator and A. wonkimi sp. nov. is remarkably variable in the length and shape of the rostrum, and the development, shape and direction of adrostral teeth ( Fig. 11 ; see also Crosnier & Forest 1966). This variability is reminiscent of the situation in another transisthmian snapping shrimp species pair, A. cylindricus Kingsley, 1878 – A. vanderbilti Boone, 1930 (Anker et al. 2008a). Although some variation was found in the proportions of the major and minor chelipeds, ratios of the carpal articles in the second pereiopod (as in A. malleator ), shape of the scaphocerite blade and the uropodal diaeresis, and some other characters, none of them was consistent to be used as a differentiating feature between A. wonkimi sp. nov. and A. malleator . Similarly, no differences were found in the colour pattern of the body, chelipeds and other appendages between A. wonkimi sp. nov. and A. malleator ( Figs. 6 , 9 , 10 ). However, it must be noted that the presently available information on the colour pattern of A. malleator is rather limited as photographs in Fig. 6 show immature or freshly dead specimens. Therefore, fresh material of A. malleator from both the western and eastern Atlantic, with high-quality colour photographs (like those available for A. wonkimi sp. nov.), as well as DNA sequencing and comparison of the African, Brazilian and Caribbean materials, are desirable to confirm the above proposed taxonomic assignments.

Figures

FIGURE 1. Alpheus malleator Dana, 1852: male from Isla Grande, Panama (USNM) [A – L]; male from Puerto Rico (MNHN- IU- 2010 - 4194) [M], A, frontal region, dorsal view; B, same, lateral view; C, third maxilliped, lateral view; D, second pereiopod, lateral view; E, right third pereiopod, lateral view; F, same, distal propodus and dactylus, lateral view; G, second pleopod, lateral view; H, same, detail of appendix masculina and appendix interna; I, right uropod, dorsal view; J, left uropodal exopod, dorsal view; K, telson, dorsal view; L, left third pereiopod with aberrant number of spiniform setae, lateral view; M, detail of left uropodal exopod.

FIGURE 6. Alpheus malleator Dana, 1852: A, male from São Paulo, Brazil (MZUSP 28270); B, young male from the Caribbean coast of Panama (not deposited); C, male from Santiago, Cape Verde (USNM); D, young female from Santiago Cape Verde (USNM). Photographs: A, Valter Cobo; B, Carl C. Hansen / Nancy Knowlton; C, D, Nancy Knowlton.

FIGURE 7. Alpheus wonkimi sp. nov.: paratype, male from Río Mar, Panama (RMNH. D. 55154) [A – L]; paratype, male from Río Mar, Panama (USNM) [M, N, P]; paratype, female from Río Mar, Panama (MNHN-IU- 2010 - 7926) [O, Q], A, frontal region, dorsal view; B, same, lateral view; C, third maxilliped, lateral view; D, major cheliped, lateral view; E, minor cheliped, lateral view; F, dactylus of major chela, lateral view; G, second pereiopod, lateral view; H, third pereiopod, lateral view; I, second pleopod, lateral view; J, same, detail of appendix masculina and appendix interna; K, uropodal exopod, dorsal view; L, telson, dorsal view; M, second pereiopod, lateral view; N, dactylus of major chela, lateral view; O, same, lateral view; P, distal uropodal exopod, dorsal view; Q, same, dorsal view.

FIGURE 8. Alpheus wonkimi sp. nov.: non-type male from Ecuador (MNHN-IU- 2010 - 4195), A, frontal region, dorsal view; B, major chela in situ, mesial view; C, same, lateral view; D, minor chela, detached, mesial view; E, same, lateral view. Scale bars estimated.

FIGURE 9. Alpheus wonkimi sp. nov.: holotype, male from Río Mar, Panama (MNHN-IU- 2010 - 7925), dorsal (A) and lateral (B) views.

FIGURE 10. Alpheus wonkimi sp. nov.: non-type male from Las Perlas Islands, Panama (OUMNH. ZC 2012 - 07 - 0145), dorsal (A) and lateral (B, C) views.

FIGURE 11. Variation of the rostro-orbital region of the carapace in Alpheus malleator Dana, 1852 [A – H] and Alpheus wonkimi sp. nov. [I, J]: A, male from Isla Grande, Panama (OUMNH. ZC 2012 - 07 - 0146); B, C, males from Puerto Rico (MNHN-IU- 2010 - 4194, MNHN-IU- 2010 - 4199); D, E, two males from São Paulo, Brazil (MZUSP 13094); F, male from Djeno, Congo (MNHN-IU- 2010 - 4197); G, H, ov. female (G) and male (H) from Loos Islands, Guinea (MNHN-IU- 2010 - 4192); I, paratype, female from Río Mar, Panama (MNHN-IU- 2010 - 7926); J, paratype, male from Río Mar, Panama (USNM).