Alpheus platycheirus Boone, 1927

Bracken-Grissom, Heather D. & Felder, Darryl L., 2014, Provisional revision of American snapping shrimp allied to Alpheus floridanus Kingsley, 1878 (Crustacea: Decapoda: Alpheidae) with notes on A. floridanus africanus, Zootaxa 3895 (4), pp. 451-491 : 474-482

Alpheus platycheirus Boone, 1927

( Figures 2 j–l, 15a–f, 16a–h, 17a–g, 18a–g, 19a–h)

Alpheus platycheirus— Boone 1927: 131 –135, figs. 29, 30 ( Cuba).

Alpheus floridanus— Chace 1972: 65 (part, fig. 20a–f, Louisiana); Felder et al. 2009: 1057, 1091 (part, Louisiana). Alpheus floridanus— Christoffersen 1979: 312 (part, Rio de Janeiro).

? Alpheus floridanus Kingsley, 1878 (part, mutilated male syntype of A. floridanus , MCZ 4987, see text).? Alpheus platycheirus— Boone 1930: 49 –51, figs. 9, 9a ( Haiti).

Type material. Holotype: 1 male, cl = 11.4 mm ( YPM 6628 = tissue/sequence ULLZ 8630) Siguanea Bay, Isle of Pines, Cuba, R/V “Pawnee I”, trawl, 12 fathoms, 1925.

Additional material. USA, N Gulf of Mexico: 1 male ( USNM 1265090 = tissue/sequence ULLZ 5855), off Louisiana/Mississippi, 28°20.60’N, 90°46.93’W, stn. Core 1, box core, R/V Pelican, 54 m, 2 July 2001, D. Felder et al.; 1 male, ( ULLZ 1181), off Louisiana/Mississippi, 28°55.40’N, 89°48.80’W, stn. 14847, R/V Oregon II, 36.5 m, 5 June 1974, T. Shirley; 1 male ( ULLZ 11936), off Lousiana, trawl, R/V Pelican, stn. 1294, LA WLF Seamap Cruise, April 2010, S. Pecnik et al.; 1 male ( ULLZ 11937), off Lousiana, trawl, R/V Pelican, stn. 1214, LA WLF Seamap Cruise, April 2010, S. Pecnik et al.; 1 male ( ULLZ 11939), off Lousiana, trawl, R/V Pelican, stn. 1188, LA WLF Seamap Cruise, April 2010, S. Pecnik et al.; 1 male ( ULLZ 10599), off Lousiana, box dredge, R/V Pelican, 58-60 m, 1 August 2002, D. Felder et al.; 1 female ( ULLZ 8275), Lousiana, off Mississippi River Delta, 90°W, box core, 28 March 1996, 91 m, D. Felder et al.; 1 juvenile ( ULLZ 6819), off Louisiana, 28°48.09’N, 89°22.89’W, stn. NSF-III-0 0 7, box core, R/V Pelican, 86 m, 28 July 2006, D. Felder et al.; 1 male ( ULLZ 5857), Louisiana, off Mississippi River Delta, stn. MP299, mud, 16 September 2002; 1 ovig. female ( ULLZ 6209), off Louisiana, 28°87’N, 90°46’W, stn. C6B R1, March 2004, M. Millman et al.; 1 male ( ULLZ 6210), off Louisiana, 28°87’N, 90°46’W, stn. C6B R2, December 2003, M. Millman et al.; 1 male ( ULLZ 6460), off Louisiana, box core, 122 m, 28 March 1996, D. Felder et al.; 1 female ( GCRL 2496), offshore, NOAA project; 2 males ( GCRL 2497), offshore, 13 June 1992, NOAA project; 1 male ( GCRL 2498), off Mississippi, south of Dog Keys Pass, 30°812.50’N, 88°47.30’W, 20 March 1998, NOAA project; 1 male ( GCRL 2500), offshore, 2 November 1993, NOAA project; 3 males, 4 females (1 ovig.) ( GCRL 2495), offshore, NOAA project; 1 ovig. female ( ULLZ 5858), off Louisiana, 29°17’N, 88°59.5’W, R/V Oregon II, 12 m, 15 April 1980, R. Bouchon and R. Foreman; 1 male ( ULLZ 9583), Texas, Seven and One-half Fathom Reef, 26°51’N, 96°51’W, mud sample between rocks, 26 August 1968, W. Tunnell; 1 female ( ULLZ 6421), Mississippi River off South Pass, soft mud, box core, R/V Pelican, 91 m, 25 May 1990, D. Felder et al.; 4 males ( USNM 103528), off Louisiana, south of Grand Isle, trawl, 37 m. Mexico, SW Gulf of Mexico: 1 male ( ULLZ 12269), off Veracruz, Enmedio Reef, in mud from discarded tin pot, 19 June 1978, W. Tunnell. Caribbean Sea: 1 male ( USNM 1071493 = tissue/sequence ULLZ 8627), off Colombia, Gulf of Morrosquillo, 0 9°36.12’N, 75°51.46’W to 0936.17’N, 75°52.40’W, trawl, CIOH-INVEMAR-Smithsonian Expedition, 38–40 m, 3 August 1995, R. Lemaitre and N. Campos; 1 male ( USNM 1071493A = tissue/sequence ULLZ 9258), 1 ovig. female ( USNM 1071493B = tissue/sequence ULLZ 9259), 1 male ( USNM 1071493C = tissue/sequence ULLZ 9260), same collection data as for previous specimens; 2 females, 2 males ( USNM 1071493), same collection data as for previous specimens; 1 male, 3 females (1 ovig.) ( USNM 1071509), 1 female ( USNM 1071643), off Colombia near Ceycen Island, 0 9°41.04’N, 75°46.08’W, trawl, expedition CIOH- INVEMAR-Smithsonian, 29 m depth, 6 August 1995, R. Lemaitre et al.; 1female (MNHN-IU-2013-13189) Guadeloupe, transversal en bordure de la microalgune de Rotours, chalutage 5’, 11h15, 21 March 1978, coll. Rojas, det. Anker A. Brazil: 1 male ( USNM 144013), Rio de Janeiro, Ilha Grande, Sepetiba, stn. 190 Bde A No. 24, 4 February 1971; 1 male ( MZUSP 05372), Rio de Janeiro, Ilha Grande, 28 July 1966, det. Christoffersen 0 5 March 1983; 1 male ( MZUSP 24525), Piuma, ES, 28 March 2010, coll. Afonso Jório, det. G. Soledade 13 September 2012; 1 ovig. female, 1 male ( MZUSP 31814), Maceió, Ponto 6, 27 June 1989, det. A. Anker and P. Pachele 2013; 2 males, 4 females (MNHN-IU-2013-13192), 23°04’S, 44°14’W, Expedition Calypso 1961-62, Entre Rio de Janeiro et Santos, Navire océanographique “Calypso”, stn. DR114, 45 m, 8 December 1961, coll. Métivier, det. Christoffersen 1979.

Description (based on holotype unless otherwise indicated). Carapace with narrow, acute rostrum not exceeding first article of antennular peduncle ( Figs. 15 a–c, 16a–d, 19a–c), shallow (prominent in some) postrostral median carina extending onto carapace midlength (extending to posterior 1/4 of carapace in some), flanked anteriorly by adrostral furrows reaching posteriorly to base of eyes; ocular hoods ovate (rounded in some), extending beyond eye, unarmed; anterolateral margin of carapace not swollen adjacent to orbital hoods; pterygostomial angle evident, rounded (indistinct in some); cardiac notch deep.

Antennular peduncle first article with large ventromesial carina ending in acute tooth, first article about 2 times length of width, second article about 4 times length of width, third article about 1.5 length of width ( Figs. 15 b, 16b, d, e; 19b, c); mesial flagellum narrower than lateral, distal ½ of lateral bearing aesthetascs; stylocerite broad, lamellate, tapering into sharp tip, not over-reaching distal margin of first article. Antenna with stout basicerite bearing strong, sharp, ventrolateral tooth ( Figs. 15 c, 16b; 19c); antennal scale (scaphocerite) broad, lateral margin weakly concave to almost straight, distolateral spine slightly over-reaching rounded anterior margin of blade and third article, also reaching about to distal tip of carpocerite (falling just short in some) ( Figs. 15 a, c, 16a, b, 19a, c).

Mandible (based on ULLZ 1181) incisor process with seven well-developed teeth ( Fig. 17 a), one enlarged, on inferior half of margin, superior margin with poorly defined dentition; molar process rounded, blunt; palp twosegmented. Maxillule, maxilla, first and second maxilliped typical for genus (17b–e). Third maxilliped exopod long, slender, setose, not extending beyond antepenultimate article of endopod ( Fig. 17 f); endopod terminal article flattened, spatulate, mesial surface and periphery bearing tufts of thick setae, penultimate article subrectangular, broadening distally, bearing fringe of long setae extending from ventrodistal lip, antepenultimate article quadrate, sparsely setose.

First pereopods (chelipeds) unequal in size and shape ( Figs. 15 a, 16a, f, g; 18a–c; 19a, d–g; Boone, 1927, figs. 29, 30; Boone, 1930, figs. 9, 9a), often massively large in males (e.g., ULLZ 1181, GCRL 2497, GCRL 2500); major cheliped ischium short; merus subrectangular, ventral surface flattened, six movable spines and fringe of setae along ventromesial margin (only two in ULLZ 1181); carpus cup-shaped, small subacute tooth (rounded tubercle in some) on mesial surface protruding from ventromesial margin; major chela rectangular in outline, laterally compressed, elongate, lacking depressions or grooves, ventral margin setose, chela length about 4 times height (5.3 times in ULLZ 1181, 5 times in GCRL 2497), propodus length about 2.3 times (3-4 times in some males) dactylus length, mesial and lateral surfaces of palm flattened to weakly concave (very weakly convex in some), texture smooth to minutely granular; dactylus setose. Minor cheliped balaeniceps-shaped in male, with short ischium; merus subrectangular, ventral surface flattened, with eigth movable spines (six in USNM 1071493 = tissue/sequence ULLZ 8627, four in ULLZ 1181) and fringe of setae along ventromesial margin; carpus stout, cupshaped; chela slender, lacking depressions or grooves, chela length about 5.3 times height (often more; 5.5 times in USNM 1071493 = tissue/sequence ULLZ 8627, 9.6 times in ULLZ 1181, 8 times in GCRL 2497), palm smooth, about 1.8 times as long as dactylus, linea impressa evident, fingers densely setose, tips slightly crossing.

Second pereopod (P2-5 descriptions based in whole or part on ULLZ 1181, where missing or damaged in holotype) slender ( Figs. 15 a; 18d), ischium slightly longer than merus; carpus composed of five articles with length ratio about 1:1:1:2.8:2 (distal to proximal) (second article of carpus slightly longer than first in USNM 1071493 = tissue/sequence ULLZ 8627, not typical); chela simple, fingers slightly longer than palm, sparsely setose distally. Third pereopod robust ( Figs. 15 d; 18e), ischium armed with movable spine on ventrolateral surface; merus about twice as long as carpus; propodus slightly longer than carpus, with four movable spines along ventrolateral surface (two in ULLZ 1181, four in USNM 1071493 = tissue/sequence ULLZ 8627, five in USNM 1265090 = tissue/ sequence ULLZ 5855), setae along superior and ventral margins, fringe of setae along distal superior margin; dactylus simple, subspatulate, slightly curved. Fourth pereopod ( Figs. 15 e; 18f) similar to third, propodus with two movable spines along ventrolateral surface (one in ULLZ 1181, two in USNM 1071493 = tissue/sequence ULLZ 8627 and USNM 1265090 = tissue/sequence ULLZ 5855). Fifth pereopod more slender than third and fourth ( Figs.

15a; 18g); ischium lacking movable spine; merus slightly longer than carpus; carpus and propodus similar in length; propodus with tufts of thick setae, lacking movable spines, fringe of comb-like setae along distoventral surface, dactylus simple, curved, narrowing to acute tip.

First to fourth abdominal somites in male with posterolateral angle of pleura rounded to weakly angular ( Figs. 15 a; 16a; 19a). Male second pleopod with appendix masculina subequal in length to appendix interna ( Fig. 17 g). Telson slightly tapering ( Fig. 19 h), length about 2.4 a long as wide, two pairs of dorsal movable spines, anterior pair inserted near 3/7, posterior pair near 4/7 length of telson; posterolateral margin broadly rounded, each posterolateral angle with two small movable spines (missing in damaged holotype), mesial larger than lateral ( Fig. 19 h). Uropodal exopod subequal in length to telson, lateral margin produced with subacute tooth adjacent to strong movable lateral spine; endopod broadly subovate, slightly overreaching length of exopod and telson.

Gill formula typical for genus, including arthrobranch on third maxilliped, mastigobranch epipod on coxa of third maxilliped to fourth pereopod, setobranch on coxa of first to fifth pereopod.

Color pattern ( Fig. 2 j–l). Carapace and abdominal somites with locally interrupted coverage of pink-red to rust-brown chromatophores, sometimes in patches; pigment cover especially dense on anterior margin of carapace lateral to orbital hoods, antennular peduncles, rostral carina; dorsolateral surface of abdominal somites and proximal half of uropodal endopods with poorly defined bands; chelae with broad interconnected patches of orange to rust brown pigment, poorly (if at all) defined into encircling bands; pereopods 3-5 with diffuse reddish band on distal third of merus, and broader, less defined reddish band on carpus, more intense on extensor margin.

Size. Largest examined male at cl 13.0 mm, tl = 32.0 mm, length of major chela 23.0 mm, minor 24.5 mm (GCRL 2497); largest female cl =12.0 mm, tl = 22.0 mm, length of major and minor chelae about 8.0 mm; egg diameter 0.5 mm (USNM 1071493).

Habitat. Muddy bottom, depth range 12–122 m; all specimens were collected by dredges, trawl nets and box cores.

Distribution. Western Atlantic: Gulf of Mexico (off Louisiana, Mississippi, Mexico), Caribbean Sea (off Colombia and Guadeloupe), and Brazil.

Type locality. Isles of Pines, Cuba.

Remarks. The holotype of A. platycheirus (YPM 6628), was collected by a dredge at 12 fathoms (22 m) in Siguanea Bay, Isle of Pines (= Isla de la Junventud), Cuba. Boone provided a full description with illustrations of an undamaged specimen in her 1927 publication ( Boone 1927), although the holotype was later described as “badly mutilated” ( Boone 1930) leaving some questions as to how/when the holotype was damaged. At present, the holotype is lacking both propodi on the fifth pereopods, which is inconsistent with the specimen figured by Boone (1927, fig. 29) showing a complete specimen with intact fifth pereopods. This species was long suspected to be a member of the A. floridanus complex (e.g., Chace 1972). Our observations suggest the features of the antennal scale and propodal spines on the third and fourth pereopods of the holotype of A. platycheirus are very similar to those of the specimens from the Gulf of Mexico and Colombia that we here regard as conspecific. However, the major chela of the holotype appears to be more broadly elevated and strongly compressed compared to those of the recent materials. Mutilation of Boone’s type material (YPM 6628) also included anterior tearing of the abdomen exposing small amounts of muscle tissue that were recovered for use in genetic analyses. We were able to successfully amplify ~200 bp from 16S fragment of the holotype of A. platycheirus . The obtained sequence differed by only one bp from those of the Colombian material assigned to A. platycheirus . Since the amount of variation in this region of 16S typically exceeds 10 (up to 18) bp between other species of the A. floridanus complex, we feel this provides some molecular evidence that A. platycheirus extends from the Carribean Sea ( Cuba, Colombia) to the northern Gulf of Mexico.

The material of A. platycheirus from Haiti reported by Boone (1930) could not be located for re-examination and is therefore tentatively assigned to A. platycheirus . Two of the Haitian specimens, a male and a female (both complete), were found inside a loggerhead sponge, which is a highly unusual habitat for species of the A. floridanus complex. The third mutilated specimen was collected from a fish stomach. Importantly, Boone’s (1930) illustrations of the major and minor cheliped depart from Boone’s (1927) illustrations of the holotype specimen, however these differences seem to be attributed to differences in the illustrator’s artistic rendition (Lee Boone? vs. Helen Ziska). Other characteristics, such as the antennal scale, are in accordance with A. platycheirus .

Christoffersen (1979) provided a detailed description (including color pattern) and figures of Brazilian material of A. floridanus . In an attempt to locate Christoffersen’s material (much of which lacked catalog numbers) we requested several lots of Brazlian material from MZUSP, USNM, and MNHN. We successfully obtained material from USNM and MNHN, which was confirmed to be A. platycheirus (MNHN-IU-2013-13192, USNM 144013). However, when we requested specimens from MZUSP, we learned that catalog numbers used in Christoffersen (1979) did not match present-day catalog numbers in MZUSP (eg. MZUSP 25 was not A. floridanus , but rather a non-decapod), making direct comparison of this material impossible. Some of Christoffersen’s material, in addition to alternative lots obtained from MZUSP and molecular evidence (Bracken- Grissom et al. this volume), suggests the distribution of A. platycheirus extends to Brazil (Rio de Janerio to Maceió). However, A. floridanus was also identified among Brazilian material (USNM 310856, MZUSP 0 5322, MZUSP 25380) so careful study will be required in separating these populations (see also A. floridanus ).

Alpheus platycheirus is closely related to the eastern Pacific A. hephaestus sp. nov., from which it can be distinguished by the color pattern ( Fig. 2 j–k, g–i) and a generally deeper longitudinal furrow on the lateral surface of the major cheliped ischium in mature specimens. For genetic differences between A. platycheirus and A. hephaestus sp. nov. see Bracken-Grissom et al. (this volume). Alpheus platycheirus can be seperated from other members of the A. floridanus complex by the length of the antennal scale (not extending distinctly beyond the third article of the antennular peduncle) and lack of movable spines on the fifth pereopod ( Table 1 ).

Some males of A. platycheirus have remarkably elongate chelae, up to 6 times as long as high for the major chela and up to 10 times as long as high for the minor chela. Chace (1972) illustrated strikingly elongate chelipeds of two males from Louisiana (as A. floridanus ), which were re-examined by us and confirmed to be A. platycheirus . Elongate chelipeds were also present in some males from other localities in the northern Gulf of Mexico (e.g. ULLZ 1181, GCRL 2497, GCRL 2500) and several individuals from Brazil (e.g. MZUSP 24525, MZUSP 05372).

The second syntype specimen of A. floridanus Kingsley, 1878 (MCZ 4987, male) is tentatively assigned to A. platycheirus , based on the length of scaphocerite, armature of the propodus of the fourth pereopod ( Figs. 20 a–g, 21a–e, 22a–e; see also Table 1 ), mandible charactersitics, as well as partial gene sequences (Bracken-Grissom et al. this volume).

Figures

FIGURE 2. Color patterns of species allied to Alpheus floridanus Kingsley, 1878. Alpheus roblesi sp. nov.: a, b, dorsal and lateral views of male, cl 8.0 mm, Campeche Banks, Mexico (ULLZ 7197 A); c, lateral view of ovigerous female, cl 7.5 mm, Campeche Banks, Mexico (ULLZ 7197 B); d, dorsal view of female, cl 4.9 mm, Campeche Banks, Mexcio (ULLZ 7440). Alpheus ulalae sp. nov.: e, f, lateral view of holotype ovigerous female, cl 7.5 mm, northeastern Gulf of Mexico (USNM 1265092 = tissue / sequence ULLZ 6815). Alpheus hephaestus sp. nov.: g, lateral view of male, cl 9.1 mm, Pacific coast of Costa Rica (ULLZ 6204); h, dorsal view of male, cl 7.1 mm, Pacific coast of Panama (ULLZ 8004); i, dorsal view of male, cl 8.9 mm, Pacific coast of Panama (ULLZ 9508 A). Alpheus platycheirus Boone, 1927: j, dorsal view of damaged female, cl 7.9 mm, northern Gulf of Mexico (ULLZ 6421); k, dorsal view of ovigerous female, cl 9.0 mm, northern Gulf of Mexico (ULLZ 5858); l, dorsal view of male, cl 9.8 mm, northern Gulf of Mexico (ULLZ 5952).

FIGURE 15. Alpheus platycheirus Boone, 1927: a-f, holotype male (YPM 6628 = tissue / sequence ULLZ 8630): a, habitus, lateral; b, anterior carapace, dorsal; c, anterior carapace, lateral; d, left third pereopod, lateral (dactylus missing, epipod not shown); e, left fourth pereopod, lateral (epipod not shown). Scale bars = 2.0 mm.

FIGURE 17. Alpheus platycheirus Boone, 1927: a, f, g, male (ULLZ 1181); b – e, male, (USNM 1265090 = tissue / sequence ULLZ 5855): a, right mandible, mesial; b, right maxillule, lateral; c, right second maxilla, lateral; d, right first maxilliped, lateral; e, right second maxilliped, lateral; f, right third maxilliped, lateral; g, left second pleopod, appendix interna and appendix masculina. Scale bars = 1.0 mm (b – e), 2.0 mm (a, f, and g).

FIGURE 19. Alpheus platycheirus Boone, 1927: a, d, g, e, f, male (USNM 1071493 = tissue / sequence ULLZ 8627); h, male (USNM 1071493 = tissue / sequence ULLZ 9259); b, c, male (USNM 1071493 = tissue / sequence ULLZ 9258): a, habitus, lateral; b, anterior carapace, dorsal; c, anterior carapace, left side, lateral; d, right major cheliped, lateral; e, right major cheliped, carpus and merus, mesial; f, left minor cheliped, lateral; g, left minor cheliped, propodus and dactylus, mesial (balaeniceps setae illustrated); h, sixth abdominal somite, telson, and uropods, dorsal. Scale bars = 2.0 mm.

FIGURE 20. Alpheus sp., possibly A. platycheirus Boone, 1927: a – g, male (MCZ 4987, second syntype of A. floridanus): a, habitus, lateral; b, anterior carapace, dorsal; c, anterior carapace, lateral; d, major cheliped (lacking dactylus), lateral (setobranch not shown); e, disarticulated dactylus of major chela, lateral; f, major cheliped, proximal articles, mesial; g, right minor cheliped, mesial (dactylus possibly atypical). Scale bars = 2.0 mm.