Bull Mar Sci. 92(2):243–255. 2016 new taxa paper http://dx.doi.org/10.5343/bms.2015.1068
Two new species (Amphipoda, Senticaudata, Corophiida) from the continental slope and abyssal plain of the Gulf of Mexico
1 * 1 Laboratorio de Crustáceos, Ignacio Winfield Facultad de Estudios Superiores Manuel Ortiz 1 Iztacala, Universidad Nacional 2 Autónoma de México, Avenida Pedro-Luis Ardisson de Los Barrios 1, Los Reyes Iztacala, Tlalnepantla, Estado de México, C.P. 54090, Mexico. ABSTRACT.—Two new species of deep-sea amphipods 2 Departamento de Recursos of the genera Podocerus and Ericthonius are described and del Mar, Cinvestav. Carretera illustrated. They were collected on soft bottoms of the Bay antigua a Progreso, km 6. Apdo. of Campeche, SW Gulf of Mexico, at depths of 1400 to 2383 Postal 73-Cordemex, 97310. m. The two new species increase the numbers of Ericthonius Mérida, Yucatán, Mexico. species recorded to 22, the Podocerus species to 58, and the * Corresponding author email: deep-sea amphipods from the Gulf of Mexico to 17 species.
Gammaridean amphipods represent a predominantly marine group of crustaceans that are numerous and dominant in benthic communities. They have colonized dif- ferent offshore habitats as herbivores, detritivores, micropredators, and scavengers (Marques-Junior and Senna 2013). In the deep-sea benthos, the amphipod suborders Gammaridea and Senticaudata are well represented from the continental slope to the abyssal plains (Cartes and Sorbe 1999). However, knowledge of biodiversity and geographic distribution of deep-sea amphipods remains limited in most oceanic ba- sins due to lack of adequate sampling, and the efficiency of the sampling gear used (Martínez-Arbizu and Brix 2008, Brökeland and George 2009, Dauvin et al. 2012). The study of benthic amphipods of the Gulf of Mexico (GoM) has focused mainly on coastal habitats, in addition to the continental shelf and the continental upper slope from 20 to 550 m depth (Myers 1981, Pequegnat et al. 1990, Ortiz 1991, LeCroy 1995, Lowry and Stoddart 1997, LeCroy et al. 2009). According to Escobar-Briones and Winfield (2003), the number of benthic amphipod species from the GoM ba- sin decreases from the inner continental shelf to shelf edge. Winfield et al. (2006) documented a total of 15 deep-sea amphipod species associated with soft bottom, of
Bulletin of Marine Science 243 © 2016 Rosenstiel School of Marine & Atmospheric Science of the University of Miami 244 Bulletin of Marine Science. Vol 92, No 2. 2016
Figure 1. Map of the Gulf of Mexico showing the sampling locality at Bay of Campeche. Marks, square = station 65_41; circle = station 65_33. which 10 species inhabit the continental slope (200–2000 m depth), and five species the Sigsbee abyssal plain (>2000 m depth). The GoM is a semi-closed oceanic basin connected with the Caribbean Sea by the Yucatán Channel and the Atlantic Ocean throughout the Straits of Florida. The Bay of Campeche, positioned in the southwest GoM (Fig. 1), is a complex topographic region with canyons, submarine channels and knolls, and is documented as one of the most productive areas in the GoM (Salas de León et al. 2007). During an oceanographic cruise (2013-PEMEX-EPRM) along the Bay of Campeche, several peracarid crustaceans were collected from soft bottom samples of the conti- nental slope and the abyssal plain. Among this material, amphipods of the families Ischyroceridae and Podoceridae were recognized and represent two new species of the genera Ericthonius and Podocerus. The present study describes the two new spe- cies and updates the benthic amphipod species diversity of the GoM occurring from the continental slope to the abyssal plain.
Methods
Study Area.—The Bay of Campeche is located in the southwestern GoM, bound on three sides by the Mexican states of Campeche, Veracruz, and Tabasco. The area of the bay covers 9700 km2 with depths >200 m. At the shelf edge, the depth increases rapidly to 1000 m, reaching >3000 m at the central part of the bay (Expósito-Díaz et al. 2009). The continental slope includes canyons, submarine channels, escarpments, salt domes, and foldings that extend from the shelf edge to the upper limit of the con- tinental rise at depths of 2800 m in the north and west to 3600 m off the Campeche Escarpment (Bryant et al. 1991). The material examined in this study was collected during the Oceanographic Expedition 2013 – PEMEX Exploración y Producción Regiones Marinas (Bay of Campeche, SWW GoM, July 2013), aboard the RV Justo Sierra of the Universidad Winfield et al.: New amphipod species from the Gulf of Mexico 245
Nacional Autónoma de México (UNAM). Position coordinates for the sampling sta- tions were plotted using a SIMRAD-NSS12-EVO2, GPS navigation system. During the oceanographic cruise samples were obtained from 50 to 3260 m using a Hessler- Sandia MK II benthic box corer. Four samples were taken from each sampling sta- tion by using a PVC corer (diameter of 20 cm). Material was sieved with a 500-µm mesh and fixed with MgCl2 and 4% formalin. In the laboratory, organisms were sepa- rated, washed, and preserved in 70% alcohol. All material was examined, dissected, and illustrated in the Laboratory of Crustaceans (FESIztacala-UNAM) using Motic Microscopes SMZ168 and BA210, both equipped with a camera lucida. Illustrations were completed using the Corel Draw V-X7 program. Measurements of type material were made with the Motic Images Plus v2 program. The type material of amphipods is deposited in the Colección Nacional de Crustáceos (CNCR), Instituto de Biología, Universidad Nacional Autónoma de México.
Results
Order Amphipoda Latreille, 1816 Suborder Senticaudata Lowry and Myers, 2013 Infraorder Corophiida Leach, 1814 (sensu Lowry and Myers, 2013) Family Ischyroceridae Stebbing, 1899 Genus Ericthonius Milne-Edwards, 1830 Ericthonius camposi new species (Figs. 2–5) urn:lsid:zoobank.org:act:2E2E250E-52E8-4303-BBD0-7AD66D66BE17
Material Examined.—Holotype.—Adult male, 5.5 mm length (CNCR30085); col- lected from the type locality; station 65_33; July 30, 2013; coll., María Teresa Herrera- Dorantes. Paratype.—Incomplete juvenile (3.1 mm), same date as holotype. Type Locality.—The material was collected from soft bottom characterized by mud (silty-clay) sediments of terrigenous origin, at 1400 m in depth; 20°00´N and 94°00´W. Diagnosis.—Head elongate; rostrum short; lateral cephalic lobes projected, sub- acute with pointed tip; a large robust seta on cephalic anteroventral corner; gna- thopod 1 coxal plate small and rectangular, basis posterior margin with a large posteromedial protuberance; gnathopod 2 coxal plate subrectangular, posteroven- tral margin with stridulating ridge, five robust setae on anteroventral margin, carpus elongate and curved; coxal plate 5 deeper than wide, eleven ventral setae; coxal plate 6 small; coxal plate 7 convex; stridulating ridge on posteroventral margin of epimera 2–3; uropod 1 peduncle bearing seven short robust setae on outer margin; uropod 3 ramus with two proximal robust setae, tip with three acute protuberances, and a simple seta. Description.—Holotype: adult male (CNCR30085), 5.5 mm total length. Body (Fig. 2) head elongate, rostrum short, lateral cephalic lobes projected, subacute with pointed tip; eyes large; large robust seta on cephalic anteroventral corner. Antenna 246 Bulletin of Marine Science. Vol 92, No 2. 2016
Figure 2. Ericthonius camposi sp. nov., holotype: adult male 5.5 mm length, CNCR30085. Habitus. Scale bar: 1.0 mm.
1, peduncular article 1, 0.75× length head; posterior margin with four subdistal aes- thetascs and several simple setae; five facial simple setae; anterior margin with two tufts of simple setae. Antenna 2 peduncular articles 1–3, 0.5× length of head; several marginal simple setae. The rest of antennae 1 and 2 missing. Gnathopod 1 (Fig. 3A) smaller than 2, subchelate; coxal plate 1 subrectangular; basis wide, dorsal margin convex, a large posterodorsal protuberance, two postero- ventral robust setae subdistally; ischium the smallest; merus with two robust setae and an acute process; carpus subtriangular with ventral margin serrate; propodus triangular; palm with minute spines; dactylus elongate subequal in length to palm, posterior margin with many small indentations where simple setae are inserted. Gnathopod 2 (Fig. 3B) carpus and propodus elongate, 0.5× length of body, carpo- chelate; coxal plate 2 subrectangular, deeper than broad, stridulating ridge on pos- teroventral margin, five robust setae on anteroventral margin; basis elongate; carpus 1.5× length of head, with distinct free posterior expansion, margin extended into two carpal teeth; propodus shorter than carpus, subconical; dactylus slender, 0.75× length of propodus. Mouthparts: left mandible (Fig. 4A) incisor 7-dentate, lacinia mobilis 4-dentate (right mandible incisor 6-dentate, lacinia mobilis 3-dentate); mandibles with seven rakers each; molar strong, triturative; mandible palp large, 3-articulate, second ar- ticle longest, third lanceolate. Maxilla 1 (Fig. 4B) inner plate conical, apically acute; outer plate longer than wide, 15–16 distal setae; palp 2-articulate, second article lon- ger than outer plate, nine distal and five subdistal robust setae. Maxilla 2 (Fig. 4C) plates heavily setose; inner plate with a row of 12 robust facial setae. Lower lip (Fig. 4D) inner and outer lobes setose, distally; mandibular lobes large and acute. Upper lip (Fig. 4E) ventrally setose, epistome strongly projected anteriorly. Maxilliped (Fig. 4F) inner plate with six apical robust setae; outer plate with seven inner marginal robust setae; palp 4-articulate, article 1 with small inner apical protuberance, article 2 the largest. Winfield et al.: New amphipod species from the Gulf of Mexico 247
Figure 3. Ericthonius camposi sp. nov., holotype. (A) gnathopod 1; (B) gnathopod 2. Scale bars: A, 0.5 mm; B, 1.0 mm. Arrows indicate the ventral margin of carpus, and margins of palm and dactylus.
Figure 4. Ericthonius camposi sp. nov., holotype. (A) Mandibles (left not included palp, right with palp); (B) maxilla 1; (C) maxilla 2; (D) lower lip; (E) upper lip; (F) maxilliped. Scale bar: 0.001 mm. 248 Bulletin of Marine Science. Vol 92, No 2. 2016
Figure 5. Ericthonius camposi sp. nov., holotype. (A) pereopod 5; (B) pereopod 6; (C) pereopod 7; (D) uropod 1; (E) uropod 2; (F) uropod 3; (G) telson. Scale bar: 0.03 mm.
Pereopods 3 and 4 missing. Pereopod 5 (Fig. 5A) coxal plate deeper than wide (Fig. 2), 10 ventral setae; basis large, ovoid; merus projected posterodistally; dactylus large and acute with a robust seta. Pereopod 6 (Fig. 5B) coxal plate small (Fig. 2); basis subrectangular; merus produced distally; carpus and propodus subequal in length, dactylus acute with a robust subdistal setae. Pereopod 7 (Fig. 5C) the longest; coxal plate convex (Fig. 2); basis slightly deeper than wide; merus and propodus subequal in length; dactylus acute with a robust seta. Epimeral plates 1–2 ventral margins con- vex (Fig. 1); plate 3 produced backward, stridulating ridges on distoventral margin of epimera 2–3. Uropod 1 (Fig. 5D) long; peduncle bearing seven short robust setae on lateral margin, medial margin with four long robust setae, middle inner margin pectinate; outer rami slightly longer than inner, five robust setae on outer margin, three on in- ner margin, pectinate with four long robust setae, distally; inner ramus with both margins pectinate, three robust setae on inner margin and two distally. Uropod 2 (Fig. 5E) shorter than uropod 1; peduncle with three robust setae on each margin, mediodistal corner with long robust seta, 0.4× length inner ramus; outer and inner rami subequal in length; inner ramus lateral margin pectinate, three marginal ro- bust setae and another submarginal, two robust setae distally; outer ramus with four marginal robust setae, both margins pectinate, four robust setae distally. Uropod 3 (Fig. 5F) small, uniramous; peduncle stout, two robust setae on ventral margin, dor- sal margin with a proximal robust seta, three simple and three robust distal setae; single ramus short, 0.4× length of peduncle, two proximal robust setae, tip with three acute-recurved protuberances, and a simple seta. Telson (Fig. 5G) entire, short, with a pair of spinulose lobes (dorsally tuberculate). Etymology.—This new species is named in honor of Ernesto Campos González, a renowned carcinologist of the Universidad Autónoma de Baja California, Mexico, for his valuable contribution to the study of the systematics of pinnotherid crabs. Winfield et al.: New amphipod species from the Gulf of Mexico 249
Remarks.—The ischyrocerid genus Ericthonius is characterized by hooked unira- mous uropod 3, gnathopod 2 carpochelate in male and telson denticulate (Barnard and Karaman 1991). According to Myers and McGrath (1984) the new species de- scribed in this paper belongs to Group 1 of Ericthonius, based on gnathopod 2 coxal plate with stridulating ridges, which is separated from (not contiguous with) coxal plates 1 and 3, and a gnathopod 2 carpus with two posterodistal teeth. Males of Ericthonius camposi sp. nov., are most similar to males of Ericthonius brasiliensis (Dana, 1852), Ericthonius punctatus (Bate, 1857), and Ericthonius parabrasiliensis Just, 2009. These species share a short rostrum, large eyes, lateral cephalic lobes pro- jected with an acute tip, coxal plate deeper and larger in 1 and 3, and elongated gna- thopod 2 basis. Males of E. camposi sp. nov., are readily distinguished from the three Ericthonius species by the following characters: (1) a large robust setae on anteroven- tral cephalic corner vs minute (E. brasiliensis) or absent (E. punctatus and E. para- brasiliensis); (2) in having a subrectangular vs subquadrate (E. parabrasiliensis) or subovate (E. brasiliensis and E. punctatus) coxal plate 1; (3) in having coxal plates 5–7 are not protruding in E. camposi sp. nov., vs protruded posterodorsally; (4) in hav- ing stridulating ridges on distoventral margin of epimera 2–3 in E. camposi sp. nov., vs no stridulating ridges; (5) in having a large protuberance anterodorsal on basis of gnathopod 1 vs small (E. brasiliensis) or no anterodorsal protuberance (E. punctatus and E. parabrasiliensis); (6) in having ventral margin of gnathopod 1 merus serrate in E. camposi sp. nov., vs smooth; (7) two proximal robust setae on inner margin of ramus of uropod 3 in E. camposi sp. nov., vs none.
Family Podoceridae Leach, 1814 Genus Podocerus Leach, 1814 Podocerus delacruzi new species (Figs. 6–9) urn:lsid:zoobank.org:act:117414C3-A196-45D9-8E1F-0476159BEC0F
Material Examined.—Holotype.—Adult male, 4.6 mm total length (CNCR30086); collected from the type locality; station 65_41; July 31, 2013; coll., María Teresa Herrera-Dorantes. Paratype.—Incomplete juvenile (2.5 mm), same date as holotype. Type Locality.—The material was collected from soft bottoms characterized by mud (silty-clay) sediments of terrigenous origin, 2383 m in depth; 20°30´N and 94°00´W. Diagnosis.—Head with rostrum; eyes ovate; pereonites 2–4 with dorsal carina- tions; pereonite 7 and pleonites 1–2 posterodorsally produced; coxal plate 1 short; coxal plate 2 the largest, subtrapezoidal; coxal plates 5–7 broadly rounded distally, each with three robust setae; gnathopod 1 propodus subtriangular, 6–7 rows of large pectinate setae submarginally, palm setose, five robust setae proximally; gnathopod 2 propodus with numerous large robust setae along dorsal margin; urosome with pairs of robust setae, dorsally; uropods 1–2 peduncle with distal peduncular process; inner distal margin of peduncle uropod 2 ovate with a robust setae; telson produced and armed with seven large robust and four short setae. Description.—Holotype: adult male (CNCR30086): total length 4.6 mm. 250 Bulletin of Marine Science. Vol 92, No 2. 2016
Figure 6. Podocerus delacruzi sp. nov., holotype: adult male 4.6 mm length, CNCR30086. Habitus. Scale bar: 1.0 mm. Setae were not included.
Body (Fig. 6), head with rostrum, eyes large and ovate; pereonites 2–4 dorsal ca- rinae; pereonite 7 and pleonites 1–2 posterodorsally produced; epimeral plates 1–3 subquadrate, without ornamentation. Antenna 1 (Fig. 7A), peduncle article 2, slightly longer than article 3, 0.25× length of article 3; flagellum 4-articulate; peduncle and flagellum with setose ventral margin; accessory flagellum uniarticulate, with four distal simple setae. Antenna 2 missing. Gnathopod 1 (Fig. 7B) coxal plate shorter than 2, as deep as wide, five simple setae; basis elongate and expanded, distally; ischium with a protuberance on anterior mar- gin; merus quadrangular with some large and small simple setae on ventral margin; carpus larger than merus, dorsal margin slightly crenulate, posterior margin strong- ly produced, lobate, bearing long and short simple setae; propodus triangular, with seven rows of large facial pectinate setae; palm setose, five robust setae proximally; dactylus fitting palm, subequal in length to palmar margin, inner margin serrate at distal half. Gnathopod 2 (Fig. 7C) coxal plate the largest, subtrapezoidal extending ventrally, with four simple setae; basis elongate with eight short robust setae in a group on posterior margin, 2-2-3; ischium short with plumose setae ventrodistally; merus with brush of large plumose setae posteriorly; carpus indistinct, almost en- tirely merged with propodus; propodus elongate and curved, longer than basis, 1.2× length; palm spinose, poorly defined, oblique with brush of large plumose setae, pos- teriorly, other simple setae arranged in transverse rows, several large and short ro- bust setae at dorsal margin, and other facial; dactylus elongate, 0.75× length of palm. Mouthparts: Maxilla 1 (Fig. 8A), inner plate vestigial; outer plate with nine thick bi-dentate apical setae; palp 2-articulate, first article short, second longer than outer plate, three apical robust setae and six submarginal large simple setae. Maxilla 2 (Fig. 8B) inner plate elongate, shorter than outer, four marginal robust setae, other distal large simple setae; outer plate extending distally, eleven minute teeth, 20 large, and 25 small apical simple setae, anterodorsal margin with a row of minute simple setae. Left mandible (Fig. 8C), both incisor and lacinia mobilis 4-dentate (right mandible lacinia mobilis 5-dentate, incisor 4-dentate), three rakers, and three plumose setae marginally; molar strong and triturative with an accessory large plumose setae; palp 3-articulate, first article the shortest, second article with five facial and 15 marginal setae, third article rectangular, six facial robust setae, and five long subdistal and 24 distal plumose setae. Upper lip (Fig. 8D), epistome subpyramidal with minute distal Winfield et al.: New amphipod species from the Gulf of Mexico 251
Figure 7. Podocerus delacruzi sp. nov., holotype. (A) antenna 1; (B) gnathopod 1; (C) gnathopod 2. Scale bars: A, 1.0 mm; B–C, 0.5 mm. simple setae; labrum subconical with distal minute setae. Lower lip (Fig. 8E), both outer and inner lobes setulose; mandibular process lanceolate. Maxilliped (Fig. 8F), inner plate with a very stout tooth-like at mediodistal corner, and seven small robust setae along distal margin; outer plate with a row of eleven tooth-like robust setae along medial margin; palp 4-articulate, articles 2–4 setose on inner margin, last ar- ticle with three apical pectinate robust setae. Pereopods 3 and 4 similar (Fig. 6), coxal plate 3 subquadrate, slightly concave; coxal plate 4 with a middle-ventral cusp, and an anteroventral robust seta. Pereopod 3 (Fig. 9A), basis elongate, many robust setae marginally; ischium short; merus produced anterodistally, many robust and simple setae marginally; carpus elongate subequal in length to merus, some marginal robust and simple setae; propodus elongate longer than carpus, simple and robust setae marginally; dactylus lanceolate. Pereopods 5–7 similar (Fig. 6), coxal plates broadly rounded and convex, each with three robust se- tae. Pereopod 5 (Fig. 9B) basis large and expanded anteriorly, with some marginal ro- bust setae; ischium short; merus expanded posterodistally, with many robust setae; carpus subequal in length to merus, some marginal robust setae; propodus elongate with many robust setae marginally; dactylus lanceolate. Urosome (Fig. 9C), urosomite 1 with two marginal robust setae; urosomite 2 with four pairs of dorsal robust setae; urosomite 3 with two pairs of robust setae. Uropod 1 (Fig. 9D) larger than uropods 2 and 3, peduncle with two rows of robust setae along medial and lateral margins, eight on the medial margin, and five on the lateral margin; also with robust distal peduncular process; outer ramus shorter than inner, outer ramus with a row of five medial, one subdistal, and two apical robust setae; inner ramus with a row of eight submarginal, four medial, and three apical robust setae, inner margin with minute setae. Uropod 2 (Fig. 9C), peduncle short and lightly expanded with a robust setae distally at inner margin, two robust setae at outer cor- ner, and one distal robust peduncular process; outer ramus shorter than inner, 0.6x length of inner ramus, two submarginal robust setae, three distally; inner ramus wide and elongate, two rows of submarginal robust setae, two distal robust setae, one larger, 0.6× length to inner ramus. Uropod 3 (Fig. 9C) fleshy and curved, bearing 252 Bulletin of Marine Science. Vol 92, No 2. 2016
Figure 8. Podocerus delacruzi sp. nov., holotype. (A) maxilla 1; (B) maxilla 2; (C) left mandible; (D) upper lip; (E) lower lip; (F) maxilliped. Scale bar: 0.005 mm. three marginal minute plumose setae. Telson (Fig. 9C, E) produced and armed with seven large and four short robust setae. Etymology.—This new species is named in honor of Gustavo de la Cruz Aguero, a renowned benthic ecologist of Instituto Politécnico Nacional – CICIMAR-BCS, Mexico. Remarks.—The genus Podocerus is characterized by having a very short subtrian- gular rostrum, a corrugated body with protuberances, teeth, or carinae, or occa- sionally smooth, last 2–3 pereonal segments often fused, and urosomite 1 elongate (Barnard and Karaman 1991). Males of Podocerus delacruzi sp. nov., are most simi- lar to males of Podocerus kleidus Thomas and Barnard, 1992, Podocerus lazowasemi Baldinger and Gable, 1994, and Podocerus cristatus Thomson, 1879. These species all share a rostrum, large and protruding eyes; small tooth process on article 2 of anten- na 2; pereonite 7 and pleonites 1–2 posterodorsally produced; gnathopod 2 propo- dus elongate and subtrapezoidal; peduncle uropods 1–2 each with distal peduncular process. Males of P. delacruzi sp. nov., are readily distinguished from the other three Podocerus species by the following characters: (1) pereonites 2–4 with dorsal carina- tions in P. delacruzi sp. nov., vs pereonites no carinations; (2) rostrum large and acute vs short (P. kleidus and P. lazowasemi) or minute (P. cristatus); (3) eyes ovate in P. delacruzi sp. nov., vs rounded; (4) tooth process on article 2 of antenna 2 anteroven- tral in P. delacruzi sp. nov., vs distoventral; (5) coxal plate 1 short and anteroventral and posteromedial margins expanded vs cleft (P. kleidus) or extending forward (P. lazowasemi and P. cristatus); (6) gnathopod 1 carpus with ventral margin extending likes a hump vs slightly curved (P. kleidus and P. lazowasemi) or subquadrate (P. cris- tatus); (7) gnathopod 2 palm poorly defined and smooth vs palmar protuberance P.( Winfield et al.: New amphipod species from the Gulf of Mexico 253
Figure 9. Podocerus delacruzi sp. nov., holotype. (A) pereopod 3; (B) pereopod 5; (C) urosome and uropods 2–3, dorsal view; (D) uropod 1; (E) urosome, lateral view. Scale bars: A, B, 0.5 mm; C, 0.25 mm; D, 0.26 mm. kleidus and P. lazowasemi) or robust setae (P. cristatus); (8) telson with eleven robust setae in P. delacruzi sp. nov., vs four (P. kleidus and P. lazowasemi).
Discussion
The two new species described in the preset study increase the numbers of Ericthonius species to 22, and Podocerus species to 58. Both genera inhabit mainly shallow water and continental shelf habitats. Only 10 species: Ericthonius megalops (Sars G.O., 1879), Ericthonius rubricornis (Stimpson, 1853), Ericthonius stephenseni Myers and McGrath, 1984, Ericthonius tolli Bruggen, 1909, Ericthonius brasilien- sis (Dana, 1852), Ericthonius camposi sp. nov., Podocerus danae (Stebbing, 1888), Podocerus gloriosae Ledoyer, 1986, Podocerus septemcarinatus Schellenberg, 1926, and Podocerus delacruzi sp. nov. have been collected from bathyal depths (Myers and McGrath 1984, Barnard and Karaman 1991, WoRMS 2015). Currently, including Ericthonius camposi sp. nov. and Podocerus delacruzi sp. nov., a total of 17 deep sea amphipod species, belonging to 12 families and 14 gen- era have been documented from the GoM (Table 1). Most genera are monospe- cific: Ampelisca, Argissa, Hourstonius, Cyphocaris, Eobrolgus, Leucothoe, Photis, Podocerus, Metharpinia, Stenothoe, and Stephonyx, in addition to the genera with two species each, Apocorophium, Ericthonius, and Monocorophium (Table 1). The number of species of deep sea amphipods (Gammaridea and Corophiidea) associated with soft bottom from the GoM basin decreases with depth: 11 species inhabiting the continental slope (200–2000 m depth), and six species the abys- sal plain (>2000 m depth); only the species Metharpinia floridana occurs from the continental shelf to Sigsbee abyssal plain (Table 1). The species Hourstonius tortugae, Ericthonius camposi sp. nov., Podocerus delacruzi sp. nov., Eobrolgus 254 Bulletin of Marine Science. Vol 92, No 2. 2016
Table 1. Number of deep sea amphipod species from the Gulf of Mexico. Family, species, depth (m), substratum, sector and reference are included. SB = soft bottom; HB = hard bottom; BCAM = Bay of Campeche; SAP = Sigsbee abyssal plain; MRD = Mexican ridges.
Family/species Depth Sector of GoM Reference Ampeliscidae Ampelisca agassizi (Judd, 1896) 450 SB/NE LeCroy et al. 2009 Argissidae Argissa hamatipes (Norman, 1869) 1,720 SB/NE–NW LeCroy et al. 2009 Amphilochidae Hourstonius tortugae (Shoemaker, 1933) 879 SB/BCAM Winfield et al. 2006 Corophiidae Apocorophium acutum (Chevreux, 1908) 3,600 SB/SAP Winfield et al. 2006 Apocorophium simile (Shoemaker, 1943) 1,231 SB/MRD Winfield et al. 2006 Monocorophium acherusicum (Costa, 1851) 2,600 SB/SAP Winfield et al. 2006 Monocorophium insidiosum (Crawford, 1937) 1,231 SB/MRD Winfield et al. 2006 Cyphocarididae Cyphocaris tunicola Lowry and Stoddart, 1997 200–500 HB/NE Lowry and Stoddart 1997 Ischyroceridae Ericthonius brasiliensis (Dana, 1853) 3,690 SB/SAP Winfield et al. 2006 Ericthonius camposi sp. nov. 1,400 SB/BCAM Present study Leucothoidae Leucothoe spinicarpa s. l. (Abildgaard, 1789) 600 HB/ENTIRE LeCroy et al. 2009 Photidae Photis longicaudata (Bate and Westwood, 1862) 400 SB/NE–NW LeCroy et al. 2009 Podoceridae Podocerus delacruzi sp. nov. 2,383 SB/BCAM Present study Phoxocephalidae Eobrolgus spinosus (Holmes, 1905) 200–1,290 SB/BCAM Winfield et al. 2006 Metharpinia floridana (Shoemaker, 1933) 200–3,360 SB/BCAM Winfield et al. 2006 Stenothoidae Stenothoe gallensis Walker, 1904 3,635 SB/SAP Winfield et al. 2006 Uristidae Stephonyx biscayensis (Chevreux, 1908) 494–1,455 HB/NE Lowry and Stoddart 1997 spinosus, and Metharpinia floridana are distributed in the Bay of Campeche, SW GoM. In comparison, Apocorophium acutum, Monocorophium acherusichum, Ericthonius brasiliensis, and Stenothoe gallensis occur in the Sigsbee abyssal plain, central GoM (Table 1).
Acknowledgments
The biological material used in this study comes from the “Programa de Monitoreo Ambiental del sur del Golfo de México,” carried out jointly by PEMEX Exploración y Producción, Regiones Marinas, and Cinvestav Unidad Mérida. Thanks are due to María Teresa Herrera-Dorantes (Laboratory of Benthos, Cinvestav, Mexico) for her support in sam- pling in the field and laboratory procedures. We are also thankful for the funds obtained from the FESI-DIP-PAPCA-2014-20 project, for the support of the “scientific drawing and CorelDraw” course. Winfield et al.: New amphipod species from the Gulf of Mexico 255
Literature Cited
Barnard JL, Karaman GS. 1991. The families and genera of marine gammaridean Amphipoda (except marine gammaroids). Rec Aust Mus, Suppl 13 (parts 1 and 2):1–866. Bryant WR, Lugo J, Córdova C, Salvador A. 1991. Physiography and bathymetry of Gulf of Mexico. In: Salvador A, editor. The Gulf of Mexico Basin. Geological Society of America, Colorado-USA. p. 13–30. Brökeland W, George KH. 2009. Editorial: deep-sea taxonomy, a contribution to our knowl- edge of biodiversity. In: Brökeland W, George KH, editors. Deep-sea taxonomy, a contribu- tion to our knowledge of biodiversity. Zootaxa. 2096:6–8. Cartes JE, Sorbe JC. 1999. Deep-water amphipods from the Catalan Sea slope (western Mediterranean): bathymetric distribution, assemblage composition and biological charac- teristics. J Nat Hist. 33(8):1133–1158. http://dx.doi.org/10.1080/002229399299978 Dauvin JC, Alizier S, Wepp A, Guj-Mundsson G. 2012. Diversity and zoogeography of Icelandic deep-sea Ampeliscidae (Crustacea: Amphipoda). Deep Sea Res Part I Oceanogr Res Pap. 68:12–23. http://dx.doi.org/10.1016/j.dsr.2012.04.013 Escobar-Briones E, Winfield I. 2003. Checklist of benthic Gammaridea and Caprellidea (Crustacea: Peracarida: Amphipoda) from the Gulf of Mexico Continental Shelf and Slope. Belg J Zool. 113(1):37–44. Expósito-Díaz G, Salas de León D, Monreal-Gómez MA, Salas-Monreal D, Vázquez-Gutiérrez F. 2009. Corrientes inerciales en el sur del Golfo de México. Cien Mar. 35(3):287–296. LeCroy S. 1995. Amphipoda Crustacea III. Family Colomastigidae. Mem Hourglass Cruises. 9:1–139. LeCroy S, Gasca R, Winfield I, Ortiz M, Escobar-Briones E. 2009. Amphipoda (Crustacea) of the Gulf of Mexico. In: Felder DL, Camp DK, editors. Gulf of Mexico; origins, waters and biota. Vol. 1, 1st ed. Texas A&M Univ. Press. p. 941–972. Lowry JK, Myers AA. 2013. A phylogeny and classification of the Senticaudata subord. nov. (Crustacea: Amphipoda). Zootaxa. 3610(1):1–80. http://dx.doi.org/10.11646/ zootaxa.3610.1.1 Lowry JK, Stoddart HE. 1997. Amphipoda Crustacea IV. Families Aristiidae, Cyphocarididae, Endevouridae, Lysianassidae, Scopelocheiridae, and Uristidae. Mem Hourglass Cruises. 10(1):1–148. Marques-Junior PR, Senna AR. 2013. Description of a new genus and species of the family Melphidippidae Stebbing, 1899 (Crustacea: Amphipoda) from the deep waters of Brazil. Zootaxa. 3641:463–475. http://dx.doi.org/10.11646/zootaxa.3641.4.11 Martínez-Arbizu P, Brix S. 2008. Editorial: bringing light into deep-sea biodiversity. In: Martínez-Arbizu P, Brix S, editors. Bringing light into deep-sea biodiversity. Zootaxa. 1866:5–6. Myers AA. 1981. Amphipoda Crustacea I. Family Aoridae. Mem Hourglass Cruises. 5(5):1–75. Myers AA, McGrath D. 1984. A revision of the north-east Atlantic species of Ericthonius (Crustacea: Amphipoda). J Mar Biol Assoc UK. 64:379–400. http://dx.doi.org/10.1017/ S002531540003006X Ortiz M. 1991. Amphipoda Crustacea II. Family Bateidae. Mem Hourglass Cruises. 8(1):1–31. Pequegnat WE, Gallaway BJ, Pequegnat LH. 1990. Aspects of the ecology of the deep-water fauna of the Gulf of Mexico. Am Zool. 30:45–64. http://dx.doi.org/10.1093/icb/30.1.45 Salas de León DA, Monreal-Gómez MA, Salas-Monreal D, Expósito- Díaz G, Riverón- Enzástiga ML, Vázquez-Gutiérrez F. 2007. Tidal current components in the Southern Bay of Campeche, Gulf of Mexico. Geofis Int. 2:141–147. Winfield I, Escobar-Briones E, Morrone JJ. 2006. Updated checklist and identification of areas of endemism of benthic amphipods (Caprellidea and Gammaridea) from offshore habitats in the SW Gulf of Mexico. Sci Mar. 70(1):99–108. WoRMS Editorial Board. 2015. World Register of Marine Species. Available from: http://www. marinespecies.org at VLIZ via the Internet. Accessed October 10, 2015.
B M S