Alpheus roblesi Bracken-Grissom & Felder, 2014, sp. nov.
Creators: name: Bracken-Grissom, Heather D.
name: Felder, Darryl L.
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Alpheidae
Alpheus
Alpheus roblesi

description: Alpheus roblesi sp. nov.
(Figures 2 a–d; 6a–h, 7a–g, 8a–f)
Alpheus floridanus— Chace 1972: 65, fig. 18a–e (Antigua Island) [not A. floridanus Kingsley, 1878]. Alpheus floridanus floridanus— Crosnier and Forest 1966: 267 –268, fig. 20 a (part, Gabon)
Type material. Mexico (SW Gulf of Mexico). Holotype: male, cl 5.0 mm (USNM 1265091 = tissue ULLZ 9141), Campeche Banks, 20°39.66’N, 91°57.09’W, stn. NSF-II-052, box dredge, R/V Pelican, mud, 33– 29 m, 11 June 2005, D. Felder et al. Paratypes: 1 male, cl 7.8 mm (ULLZ 7197A), 1 ovig. female, cl 7.5 mm (ULLZ 7197B), 1 female, cl 8.0 mm (ULLZ 7197C), Campeche Banks, 20°39.66’N, 91°57.09’W, stn. NSF-II-052, box dredge, R/V Pelican, mud, 33– 29 m, 11 June 2005, D. Felder et al.; 1 ovig. female, cl 8.0 mm (ULLZ 6623), 21°33.97’N, 91°04.75’W, stn. NSF-II-057, box dredge, R/V Pelican, muddy sand and rubble, 32–33 m, 12 June 2005, D. Felder et al.
Additional material. Florida: 1 juvenile (ULLZ 12208), Ft. Pierce Inlet, South AIA Causeway Flat, mudflat, 21 July 2010, D. Felder et al.; 1 juvenile (ULLZ 12202), Ft. Pierce Inlet, South AIA Causeway Flat, mudflat, yabby pump, 20 July 2010, D. Felder et al. SW Gulf of Mexico: 1 male (ULLZ 6991), 21°34.18’N, 91°04.71’W, stn. NSF-II-060, box dredge, R/V Pelican, mud, 33 m, 11 June 2005, D. Felder et al.; 1 female (ULLZ 7440), 21°34.18’N, 91°04.71’W, stn. NSF-II-060, box dredge, R/V Pelican, mud, 33 m, 11 June 2005, D. Felder et al.; 1 ovig. female (ULLZ 6549), 22°05.87’N, 91°22.96’W, stn. NSF-II-0 86, box dredge, R/V Pelican, mud, 41–42 m, 15 June 2005, D. Felder et al.; 1 female (ULLZ 9142), 20°39.66’N, 91°57.09’W, stn NSF-II-052, box dredge, R/V Pelican, mud, 29–33 m, 11 June 2005, D. Felder et al.; 1 female (ULLZ 7471), 21°36.44’N, 91°04.06’W, stn. NSF- II-084, box dredge, R/V Pelican, rubble, 30– 20 m, 15 June 2005, D. Felder et al. Caribbean Sea: 1 male (USNM 135953), Antigua, English Harbor, Tank Bay, Smithsonian-Bredin Expedition, stn. 74–56, 3 April 1956; 1 ovig. female (USNM 135954), Antigua, English Harbor, Freemans Bay, Smithsonian-Bredin Expedition, stn. 79–58, seagrass patch, 19 April 1958; 1 male (MNHN-IU-2013-12176), Guadeloupe, 16°22.57’N, 61°31.74’W, stn. GS19, Expedition: Karubenthos 2012, bouée PCA, 8 m, 15 May 2012; 1 female (MNHN-IU-2013-12174), Guadeloupe, 16°08.07’N, 6146.71’W, stn. GS12, Expedition: Karubenthos 2012, Baie de Bouillante, 6 m, 10 May 2012; 1 female (MNHN-IU-2013-16134), Guadeloupe, 16°27.34’N, 61°32.07’W, stn. GS20, Expedition: Karubenthos 2012, entrée Grotte aux Barracudas (Port-Louis), 19 m, 16 May 2012. Eastern Atlantic: 1 ovig. female (IU-2013- 13191), Africa, Gabon, Port Gentil, 0°42’S, 0 8°47’E, Expedition Calypso, stn. DC58, 10 m, coll. Marche- Marchad 16 June 1956, det. J. Forest.
Description (based on holotype unless otherwise indicated). Carapace with narrow, acute rostrum not exceeding first article of antennular peduncle, shallow median postrostral carina extending onto carapace midlength, flanked anteriorly by adrostral furrows reaching posteriorly to base of eyes (Fig. 6 a, b, c); ocular hoods ovate, barely extending beyond eye, unarmed; anterolateral margin of carapace not weakly swollen adjacent to ocular hoods; pterygostomial angle distinct, rounded; cardiac notch deep.
Antennular peduncle first article with large ventromesial carina ending in acute tooth, first article about 2.5 times length of width, second article 2.7 length of width, third article about 1.6 length of width (Fig. 6 a, b, 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; antennal scale (scaphocerite) broad, lateral margin sinuous, distolateral spine prominent, extending distinctly beyond rounded anterior margin of blade, overreaching antennular peduncle by 1.7 times length of third article, barely overreaching carpocerite (6a, b).
Mandible incisor process with eight teeth distributed along full width of cutting edge, central teeth enlarged (Fig. 7 a); molar process rounded, blunt; palp two-segmented. Maxillule, maxilla, first and second maxilliped typical for genus (Figs. 7 b–e). Third maxilliped exopod slender, setose, not extending beyond antepenultimate article of endopod (Fig. 7 f); endopod terminal article flattened, spatulate, mesial surface and periphery bearing tufts of thick setae (Fig. 7 g), 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 (Fig. 6 a, d–f); major cheliped ischium short; merus subrectangular, ventral surface flattened, with three large and one small movable spines along ventromesial margin (others may have broken off; five in paratype ULLZ 7197B); carpus cup-shaped, lacking subacute tooth protruding from ventromesial margin (present as small tubercle in some paratypes); major chela laterally compressed, subcylindrical in lateral view, lacking depressions or grooves, margins sparsely setose, chela length about 3.4 times height (2.9 times in paratype ULLZ 7197B), propodus length about 2.8 times dactylus length (also 2.8 times in paratype ULLZ 7197B), mesial and lateral surface of palm smooth; dactylus lacking obvious setae, rounded distally. Minor cheliped ischium short; merus subrectangular, ventral surface flattened, six movable spines along ventromesial margin (seven in paratype ULLZ 7197C); carpus stout, cup-shaped; chela slender (weakly balaniceps in holotype and some paratype males), long, lacking depressions or grooves, chela length about 4.8 times height (4 times in paratype ULLZ 7197C), palm smooth, about 2 times as long as dactylus (1.7 times in paratype ULLZ 7197C), linea impressa evident, fingers sparsely setose along margins, tips slightly crossing.
Second pereopod slender (Fig. 8 a), much longer than pereopods 3–5, ischium equal in length to merus; carpus composed of five articles with length ratio 1:1:1:3.7:2 (distal to proximal); chela simple, fingers slightly longer than palm, sparsely setose distally. Third pereopod robust (Fig. 8 b), ischium armed with movable spine on ventrolateral surface; merus about 1.8 times as long as carpus; propodus slightly longer than carpus, five conspicuously large movable spines along ventrolateral surface (six in paratype ULLZ 7197C, five in paratype 7197B), thick setae along entire superior and ventral margins, fringe along distal superior and ventral margin; dactylus simple, falciform. Fourth pereopod similar to third, shorter, more slender (Fig. 8 c), propodus with five large movable spines (five in paratypes ULLZ 7197C and 7197B) along ventrolateral surface. Fifth pereopod more slender than third and fourth (Fig. 8 d, e); ischium lacking movable spine; merus slightly longer than carpus; propodus with tufts of thick setae, three conspicuous movable spines along ventromesial surface (also three in paratype ULLZ 7197B), fringe of comb-like setae along distal mesial surface; dactylus simple, curved, triangular, narrowing to acute tip.
First to fourth abdominal somites in male with posterolateral angle of pleura rounded to weakly angular (Fig. 6 a). Male second pleopod with appendix masculina slightly over-reaching appendix interna (Fig. 6 g). Telson slightly tapering (Fig. 6 h), length about twice as long as width (medially); two pairs of dorsal movable spines, anterior pair inserted near 4/10, posterior pair near 6/10 length of telson; posterolateral margin broadly rounded; each posterolateral angle with two small movable spines, mesial larger than lateral. Uropodal exopod subequal in length to telson and endopod, lateral margin produced with subacute tooth adjacent to strong movable lateral spine; endopod broadly subovate, subequal in length to telson (6h).
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 a–d). Body translucent with orange and yellow chromatophores, especially on first chelipeds; abdominal somites marked dorsally by broad diffuse bands of small reddish orange to rust brown chromatophores, loosely scattered laterally, inconspicuous in translucent live specimens; carapace anterior margin lateral to orbital hoods marked by distinct vertical slash of reddish orange; chelae with palm and fingers irregularly banded by orange to rust brown; pereopods 3–5 each with weak orange band just beyond mid-length of meri and on proximal propodus, otherwise translucent pale yellow; eggs bright yellow.
Size. Largest examined male at cl 10.0 mm, tl 26.0 mm (USNM 135953); largest examined female at cl 8.0 mm, tl 22.0 mm.
Habitat. Most specimens were collected with vessel-deployed box dredges in 20–42 m depth on muddy or sandy bottoms, sometimes with calcareous rubble. However, some specimens were collected in less than 0.7 m (2 feet) of water (Chace 1972), while our material from southeastern Florida includes two juveniles collected with a yabby pump on a muddy-sandy intertidal grass flat.
Distribution. Western Atlantic: southeastern Florida, southern and southwestern Gulf of Mexico and eastern Caribbean Sea (Antigua, Guadeloupe); Eastern Atlantic: Gabon, Africa.
Type locality. Southwestern Gulf of Mexico, off Yucatan Peninsula, Campeche.
Etymology. This patronym honors our close friend and colleague, Dr. Rafael Robles, who assisted in this and many other studies of decapod phylogenetics.
Remarks. The sinuous shape of the antennal scale lateral margin, translucent color, and the presence of movable spines on the ventromesial surface of the propodus of the fifth pereopod (absent in one juvenile examined) serve to distinguish A. roblesi sp. nov. from all other species of the A. floridanus complex (see also Table 1). In addition, adult specimens of A. roblesi sp. nov. are characterized by the relatively smaller size of the body and major chela when compared to all other other members of the A. floridanus complex.
Chace’s (1972) material from Antigua was assigned to A. roblesi (fig. 18a–e) as it represents all diagnostic features of this species. However, Hendrix’s (1971) material from Florida identified as A. floridanus may contain representatives of both A. floridanus and A. roblesi sp. nov. Hendrix described a “row of 4 slender spines” on the propodus of the fifth pereopod, which is an important characteristic feature of A. roblesi sp. nov. However, Hendrix’s description of the color pattern matches A. floridanus and not A. roblesi sp. nov.
Morphological evidence suggests that the distribution of A. roblesi sp. nov. extends into the eastern Atlantic. Crosnier and Forest (1966) reported two subspecies of A. floridanus from western Africa, as A. floridanus floridanus and A. floridanus africanus. Their illustrations clearly show morphological features of A. roblesi sp. nov. for the A. floridanus floridanus variant (sinuous antennal scale margin, smaller chelae, large movable spines on the third pereopod). We examined Crosnier and Forest’s material of A. floridanus floridanus from Gabon, Africa (MNHN-IU-2013-13191) and concluded it clearly falls within the limits of A. roblesi sp. nov. (sinuous scaphocerite and presence of at least 1 spine on propodus of the 5th pereopod), suggeting this species has a trans- Atlantic distribution. From the limited African material available to us for examination we have been able to identify at least two morphotypes in the eastern Atlantic, which exhibits morphological features of A. roblesi sp. nov. and A. floridanus africanus (see discussion).
It is possible (if not probable) that A. roblesi has been taken previously at varied localities within the western Atlantic (White 1982) and more specifically the type locality, Campeche (Hernandez Aguilera et al. 1996; Roman- Contreras 1988), but materials on which those reports are based must be reexamined to confirm which member or members of the complex are represented.
description: Published as part of 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, pp. 451-491 in Zootaxa 3895 (4) on pages 460-466, DOI: 10.11646/zootaxa.3895.4.1, http://zenodo.org/record/229141