Alpheus cylindricus Kingsley, 1878

Anker, Arthur, Hurt, Carla, Jara, Javier A. & Knowlton, Nancy, 2008, Revision of the Alpheus cylindricus Kingsley, 1878 species complex (Crustacea: Decapoda: Alpheidae), with revalidation of A. vanderbilti Boone, 1930, Zootaxa 1943, pp. 53-68 : 55-60

Alpheus cylindricus Kingsley, 1878

( Figs. 1; 3A, D; 4A–D, I)

Alpheus cylindricus Kingsley 1878a: 196 ; Kingsley 1878b: 58; Lockington 1878: 478; Kingsley 1883: 120; Coutière 1899 (for page numbers see Chace & Forest 1970); Rodríguez de la Cruz 1977: 28; Carvacho & Ríos 1982: 282; Wicksten 1983: 43 (part.); Kim & Abele 1988: 47, fig. 19; Villalobos-Hiriart et al. 1989: 18; Flores-Hernandez 1991: 96; Alvarez del Castillo et al. 1992: 5; Wicksten & Hendrickx 1992: 4 (part.); Hendrickx 1992: 8; Hendrickx 1993a: 306; Hendrickx 1993b: 6; Hendrickx 1995: 432; Lemaitre & Alvarez-Leon 1992: 42; Knowlton et al. 1993: 1630 (part.); Camacho 1996: 67; Villalobos 2000: 47, fig. 23; Williams et al. 2001: 377 (part.); Wicksten & Hendrickx 2003: 63 (part.).

Crangon cylindricus — Chace 1937: 121; Schmitt 1939: 24.

Alpheus cylindrius (lap. cal.)— Vargas & Cortés 1999: 899.

Not Alpheus cylindricus — Zimmer 1913: 394; Crosnier & Forest 1965: 606; Crosnier & Forest 1966: 257, fig. 16; Hendrix 1971: 71; Coelho & Ramos 1972: 149; Chace 1972: 65; Pequegnat & Ray 1974: 246, fig. 49d; Ray 1974: 92, figs. 72–78; Christoffersen 1979: 310; Christoffersen 1980: 50; Coelho & Ramos-Porto 1980: 135; Coelho et al. 1980: 48; Abele & Kim 1986: 196, 206–207, fig. a–c; Sterrer 1986: 326, text. pl. 105, pl. 9, fig. 7; Rodríguez 1986: 138, fig. 33; Martínez-Iglesias et al. 1993: 11; Knowlton et al. 1993: 1630 (part.); Martínez-Iglesias et al. 1996: 33; Martínez-Iglesias et al. 1997: 404, fig. 9; Williams et al. 2001: 377 (part.); McClure 2005: 138, fig. 11 (reproduced from Kim & Abele 1988); Coelho et al. 2006: 51 (= A. vanderbilti Boone, 1930 ).

Not Crangon cylindricus – Schmitt 1924: 74; Pearse 1950: 150 (= A. vanderbilti Boone, 1930 ).

Type material. Panama (Pacific coast). Neotype: male (CL 9.4), USNM 1109158 , Las Perlas Islands , off Contadora, extreme low tide, rocky intertidal, from rock crevices, coll. J. Jara, C. Hurt, A. Anker, E. Tóth and E. Gómez, 31 Mar 2006 [fcn 06-373A].

Additional material. Panama ( Pacific coast). 1 ovig. female (CL 11.0), USNM 1109159 , same collection data as for neotype [fcn 06-373B] ; 1 male (CL 9.7), 1 ovig. female (CL 11.3), USNM 1109160 , same collection data as for neotype [fcn 06-367] ; 3 males (CL 6.7–8.8), 1 ovig. female (CL 9.6), USNM 1109161 , Taboga , off Taboguilla, dredged from less than 30 m, coll. P. Barber et al., 30 Sep 2005 [fcn 05-134] ; 1 male (CL 8.3), OUMNH-ZC 2007-13 - 036 , Amador causeway, Punta Culebra, rocky intertidal, extreme low tide, from sponges among mud-covered boulders, coll. A. Anker and C. Hurt, 2 Mar 2006 [06-276, with host sponge] ; 1 male (CL 6.9), 1 female (CL 7.7), USNM 1109162 , same collection data as for previous specimen [fcn 06-278, with host sponge] ; 1 male (CL 9.3), USNM 1109163 , same collection data as for previous specimen [fcn 06-274]; 1 ovig. female (CL 8.9), USNM 1109164 , same collection data as for previous specimen [fcn 06-275] ; 1 male (CL 7.5), 1 ovig. female (CL 10.0), MNHN-Na 16706, same collection data as for previous specimen [fcn 06-272, 06-273] ; 1 male (CL not determined), UP, Amador Causeway , Isla Naos , Punta Culebra, under rocks in purple sponge, low tide, coll. A. Anker and I. Marin, 17 Apr 2007 [fcn 07-124] .

Diagnosis. Species of Alpheus macrocheles group. Frontal margin of carapace with very short rostrum, without or with blunt orbital teeth; orbital hoods moderately inflated. Antennule with second peduncular segment about three times as long as wide; stylocerite with blunt tip, not reaching distal margin of first segment. Antenna with basicerite lacking sharp distoventral tooth; scaphocerite with strong distolateral tooth and reduced blade; carpocerite overreaching scaphocerite, reaching or slightly overreaching end of antennular peduncle, distomesial margin with small tooth. Third maxilliped not particularly broadened, antepenultimate and penultimate segments with rows of spines on ventral margin. Major cheliped with merus lacking sharp distomesial tooth; chela subcylindrical, without notches or constrictions; mesial face smooth; lateral face with shallow groove bordered by subacute tooth distally; adhesive disks well developed; dactylus reaching far beyond pollex, compressed, twisted laterally, with greatly reduced plunger; pollex reduced to short subacute protuberance. Minor cheliped with merus lacking sharp distomesial tooth; chela smooth; fingers slightly longer than palm, slender and strongly curved laterally, without balaeniceps setae. Second pereiopod with first carpal segment about twice as long as second; chela with groups of thickened setae. Third pereiopod with unarmed ischium; merus and carpus without spines on ventral margin, distoventral angle not projecting as tooth; propodus with row of spines; dactylus stout, biunguiculate. Male second pleopod with typical appendices masculina and interna. Uropod with protopod bearing acute lateral tooth; exopod with distolateral spine bordered laterally by sharp distolateral tooth and mesially by triangular tooth of transverse suture; endopod with row of spines on distomesial margin. Telson tapering distally, with two pairs of strong dorsal spines; posterior margin slightly convex, with two pairs of spines at each posterolateral angle.

Description. For detailed description and illustrations see Kim & Abele (1988).

Color pattern. Background color pale grey, semitransparent; carapace with broadly X-shaped patch of red chromatophores on gastric region, patches of red chromatophores also on rostral and post-rostral region; red transverse band present along posterior margin of carapace and articulation between carapace and abdomen; abdomen with broad longitudinal band of red chromatophores running along lateral surface of pleurae and dorsomedially protruding into colorless mediodorsal area, latter usually “spruce-shaped” ( Fig. 3A) and interrupted by narrow pale red band on sixth somite; walking legs colorless; second pereiopod with orangered chromatophores; antennular peduncles bright red; antennal peduncles including scaphocerite partly transparent and orange, carpocerite distally reddish; antennular and antennal flagella pale yellow; cheliped meri and carpi mostly colorless mesially, pale orange laterally; palm of major chela pale orange becoming orangebrown distally; linea impressa delimiting pale grey to whitish oval proximolaterally; dactylus purple-brown with white tip; minor chela pale orange, darker distally and on fingers ( Fig. 1, 3A); eggs in females bright yellow-orange ( Fig. 3D).

Size. The largest examined specimen is an ovigerous female from Las Perlas with CL 11.3 mm and TL 31.3 mm. Kim & Abele (1988) gave the size range of their specimens as following: CL 6.1–9.5 mm for males, 4.8–7.6 mm for females and 5.6–9.3 mm for ovigerous females.

Ecology. Largely in intertidal and shallow subtidal to about 37 m ( Kim & Abele 1988) or deeper: 64–82 m ( Chace 1937); on mud and rock-mud bottoms; also in rocky intertidal, often in pairs in unidentified greypurple sponges ( Fig. 3D) growing among or under large rocks; usually in male-female pairs ( Fig. 3D).

Type locality. Las Perlas Islands , Bay of Panama (Pacific coast) .

Distribution. Eastern Pacific from central Gulf of California to Galapagos ( Kim & Abele 1988). Specific localities include: Mexico: Cerralvo Island, central Gulf of California (Villalobos-Hiriart et al. 1989; Villalo- bos 2000); southern Baja California ( Wicksten 1983); Guayamas, Sonora ( Rodríguez de la Cruz 1977); Nayarit ( Camacho 1996); southern Sinaloa ( Kim & Abele 1988; Hendrickx 1993b); Jalisco (Alvarez del Castillo et al. 1992); Costa Rica: Puerto Culebra and Parker Bay ( Kim & Abele 1988); Panama: vicinity of Panama City, Taboga and Las Perlas Islands, Honda Bay, Secas Islands ( Kingsley 1878a; Kim & Abele 1988; present study); Colombia: Utria Sound and Gorgona Island ( Wicksten 1983; Kim & Abele 1988); Galapagos ( Schmitt 1939).

Variation. Alpheus cylindricus appears to be extremely variable in the shape of the orbital teeth and rostrum ( Fig. 4 A-D). Kim & Abele (1988) noted that the “ocular hood [is] not inflated dorsally, with anterior margin sinuous”. The illustrated specimen from Baja California had no distinct orbital teeth (cf. Kim & Abele 1988: fig. 19b). However, some of our specimens from Panama bear large, subtriangular teeth on the orbital hoods ( Fig. 4D), while others have less marked, rounded teeth ( Fig. 4B, C) or no teeth at all ( Fig. 4A). The shape of the strong tooth on the mesioventral carina of the first segment of the antennular peduncle is also somewhat variable (A. Anker, pers. obs.).

Remarks. Alpheus cylindricus is morphologically indistinguishable from A. vanderbilti , but may be separated from the latter species by the absence of red chromatophores on the posterior dorsal half of the carapace and the colorless mediodorsal band being laterally fringed by triangles (more or less “spruce-shaped”) and running without interruption from the first to the sixth abdominal somite, although there might be a few scarce chromatophores near the posterior margin of the fifth and on the sixth somites (compare Figs. 1, 3A and Figs. 2, 3B, C). Despite their morphological similarity, comparison of COI gene sequences confirm that A. cylindricus and A. vanderbilti are distinct species (see below).

GenBank accession number. EU652331 , EU652332 , EU652333 (specimens will be deposited in USNM) .