Article. Description of Ophthalmolycus andersoni sp. nov. (Pisces, Zoarcidae) from the Antarctic Ocean

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1 Zootaxa 2027: (2009) Copyright 2009 Magnolia Press Article ISSN (print edition) ZOOTAXA ISSN (online edition) Description of Ophthalmolycus andersoni sp. nov. (Pisces, Zoarcidae) from the Antarctic Ocean JESÚS MATALLANAS Grupo de Biodiversidad Animal, Unidad de Zoología (Facultad de Biociencias), Universidad Autónoma de Barcelona, E-08193, Bellaterra, Barcelona, Spain. Abstract A new species of zoarcid fish is described on the basis of three specimens collected from the Antarctic Peninsula, Antarctic Ocean. The new species can be distinguished from its congeners by its body shape and pigment pattern, and by the following combination of characters: 6 branchiostegal rays; pectoral-fin origin well below midbody, pectoral base extending ventrally to abdomen; lateral line double with ventral and medio-lateral branches; oral valve not reaching anterior edge of vomer; gill slit extending ventrally well below end of pectoral fin base; vertebrae asymmetrical =92-96; dorsal fin origin associated with vertebrae 4 or 5 with no supraneurals; pectoral fin rays 16 or 17; 2 postorbital pores (positions 1 & 4) and 2 well developed pyloric caeca. The relationships of the new species with its congeners are discussed. Key words: Antarctic Peninsula, eelpout, new species, taxonomy Resumen Se describe una nueva especie de pez zoárcido basada en tres especimenes capturados en aguas de la Península Antártica, Océano Antártico. La nueva especie se distingue de sus congéneres por su aspecto corporal y patrón de coloración, así como por la siguiente combinación de caracteres: seis radios branquióstegos; inserción de las aletas pectorales en la parte baja de los flancos y extendida hasta el abdomen; línea lateral con dos ramas, media y ventral; válvula oral que no alcanza el borde anterior del vómer; hendidura opercular sobrepasando ventralmente el extremo inferior de la base de la aleta pectoral; =90 96 vértebras asimétricas; origen de la aleta dorsal asociado con las vértebras 4 o 5 y sin supraneurales; aleta pectoral con 16 o 17 radios; 2 poros postorbitarios (en las posiciones 1 y 4) y dos ciegos pilóricos bien desarrollados. Se discuten las relaciones de la nueva especie con sus congenéricas. Introduction With 28 known species in 11 genera, according to recent revisions and descriptions (Eastman, 2005; Moeller & Stewart, 2006; Anderson, 2006, Matallanas, 2008), the family Zoarcidae is one of the most speciose benthic fish families in the Antarctic waters. The Bellingshausen Sea benthic ichthyofauna is dominated both in number and weight by zoarcids (Matallanas & Olaso, 2007). Three genera, Lycodichthys, Seleniolycus and Gosztonyia are endemic to the Antarctic Region (Anderson & Gosztonyi, 1991, Matallanas, 2008). Ophthalmolycus erected by Regan (1913) was reviewed by Gosztonyi (1977) and Anderson (1988, 1990a, 1992, 1994). According to Anderson & Fedorov (2004) it contains six species: O. amberensis, O. bothriocephalus, O. campbellensis, O. chilensis, O. conorhynchus and O. macrops). A new species, Ophthalmolycus andersoni sp. nov., from the Antarctic Ocean is described in this paper. Accepted by J.P. Friel: 23 Jan. 2009; published: 4 Mar

2 Materials and methods All the material has been deposited at the UAB ichthyological collection (Zoología, Universidad Autónoma de Barcelona). Counts, measurements and general terminology follow Gosztonyi (1977, 1988) and Anderson (1982, 1988). Measurements were made with ocular micrometer or dial callipers to nearest 0.1 mm. Osteological observations were made on stained specimens. Specimens were radiographed to record both shape and meristics of the axial skeleton and un-paired fins. Pore terminology follows Gosztonyi (1977) and Anderson (1982). Abbreviations used: SL, standard length; HL, head length. Comparative material examined. Uncatalogued specimens of Ophthalmolycus amberensis (Tomo, Marschoff & Torno, 1977) and O. bothriocephalus (Pappenheim, 1912) from Weddell Sea (UAB ichthyological collection); O. amberensis: suspensorium of specimen UAB:WSZ29, 206 mm SL, and two uncatalogued specimens 174 and 176 mm SL; O. bothriocephalus: four uncatalogued specimens, mm SL. Ophthalmolycus andersoni sp. nov. (Figs. 1 2; Table 1) Holotype. UAB:B03BSZ25, 263 mm SL male, Paradise Bay, Antarctic Peninsula, cruise BENTART-03, R/V Hespérides stn 22A, 64º S, 62º W, collected with an Agassiz trawl at 286 m depth, 24 February Paratypes. UAB:B03BSZ9, 255 mm SL male, same collection data as holotype; and UAB:B03BSZ99, 212 mm SL female, same collection data as holotype. Diagnosis. A species of Ophthalmolycus as defined by Anderson (1992, 1994) with the following combination of characters: 6 branchiostegal rays; pectoral fin origin well below midbody, pectoral base extending ventrally to abdomen; lateral line double with ventral and medio-lateral branches; oral valve not reaching anterior edge of vomer; gill slit extending ventrally well below ventral end of pectoral fin base; vertebrae asymmetrical =92 96; dorsal fin origin associated with vertebrae 4 or 5 with no supraneurals; pectoral fin rays 16 or 17; postorbital pores two (positions one and four); 2 well developed pyloric caeca and 0 3 pseudobranch filaments. Description. Body laterally compressed and relatively short; tail laterally compressed, especially posteriorly (Fig. 1). Head nearly triangular in cross section; eye ellipsoid, not entering dorsal profile of head. Scales small, sparse, present only on tail and un-paried fin bases. Gill slit extending ventrally well below lower edge of pectoral fin base (Fig. 1c). Triangular opercular flap at upper end of gill slit. Pectoral-fin origin well below midbody, pectoral-fin base with its lower end on abdomen, pectoral-fin margin rounded; ventralmost 5 7 rays thickened, tips exserted (Fig. 1c). Upper jaw protruding, end of maxilla extending to posterior margin of eye; upper jaw length apparently dimorphic, longer in the two males than in the female. Head wider in the adult male (holotype) than in paratypes (immature male and female). Mouth inferior; lower lip with a small lobe. Nasal tube long, unpigmented, overhanging upper lip. Oral valve not reaching anterior margin of vomer. Teeth in jaws, vomer and palate conical. Upper jaw with 2 or 3 rows anteriorly merging into single posterior row; lower jaw with 3 rows of teeth anteriorly and single row posteriorly. Vomerine teeth in a patch. A single row of palatine teeth. Two well-developed pyloric caeca present, their length about 66 % of eye diameter. Gill rakers , triangular. Pseudobranch filaments 0 3. Cephalic lateralis pore system with pores enlarged except the seventh and eighth preoperculomandibular, and the two postorbital pores (Figs. 1a & b). Two nasal pore, first pore located anteromesial to nasal tube, the other dorsoposterior to it. Two postorbital pores (positions 1 and 4). Six suborbital pores all on the ventral ramus. Eight preoperculomandibular pores. Interorbital and occipital pores absent. Body lateral line 56 Zootaxa Magnolia Press MATALLANAS

3 configuration with 2 rows of neuromasts (Fig. 1a): lower lateral-line beginning just behind the fourth postorbital pore, steeply sloping above pectoral fin and extending ventrolaterally to the end of the tail; middle lateral line, originated behind the anal-fin origin and coursing to tail tip. FIGURE 1. Ophthalmolycus andersoni sp. nov., holotype (UAB:B03BSZ25). a: left lateral view; b: left lateral view of head showing pore pattern; c: ventral view showing insertion of pectoral and pelvic fins, and ventral extension of gill slit. Scale bars = 10 mm. Drawing: J. Corbera. FIGURE 2. Suspensorium and preopercle of Ophthalmolycus andersoni sp. nov., paratype (UAB:B03BSZ99); external view of the right side: EC, ectopterygoid; HY, hyomandibula; MS, mesopterygoid; MT, metapterygoid; PAL, palatine; QD, quadrate; SY, symplectic; 5 8, preopercular pores. Palatopterygoid series well developed, with ectopterygoid broadly articulating with quadrate and mesopterygoid overlapping half or more dorsal margin of quadrate (Fig. 2). Metapterygoid large, thickened. Posterior ramus of hyomandibula not elongate. Hyoid bar with ceratohyal-epyhial juncture smooth. Six branchiostegal rays articulating with the hyoid arch according to the pattern of 2 on the epihyal and 4 on the ceratohyal. OPHTHALMOLYCUS ANDERSONI SP. NOV. (PISCES) Zootaxa Magnolia Press 57

4 Vertebrae asymmetrical, Last precaudal vertebra associated with dorsal fin rays 18 or 19. First dorsal fin pterygiophore associated with vertebra 4 or 5, with no free supraneurals. Terminal dorsal-fin ray associated with second preural vertebra. Anal-fin origin associated with first caudal vertebra, with 2 preanal pterygiophores and 2 anal fin rays. Second caudal vertebra with 2 pterygiophores and 2 anal fin rays. Terminal anal-fin ray associated with second preural vertebra. One epural. First pleural centrum, ural centrum, parhypural and hypurals fused into one element. Caudal fin rays 10 or 11, with 2 epural, 4 upper hypural and 4 or 5 lower hypural rays. Color in alcohol light brown not uniform; vertical fins greyish; belly, pelvic and pectoral fins ashcoloured; contour of pectoral fin dark; lips, nasal tube and cephalic pores light; lining of mouth dark grey; branchial chamber and peritoneum black. Counts and proportions. Holotype first, followed in parentheses by range of paratypes. Vertebrae 22+74=96 ( =92 95); dorsal-fin rays 91 (87 91); anal-fin rays 77 (72 74); caudal-fin rays 10 (10 or 11); pectoral-fin rays 17 (16); pelvic-fin rays 3 (3); gill rakers 3+9 (3+8 9); pseudobranch filaments 0 (2 3). Following proportions as percent SL: head length 22.1 ( ); head width 11.7 ( ); head depth 10.0 ( ); pectoral-fin length 11.4 ( ); predorsal length 24.3 ( ); preanal length 41.8 ( ); body depth 8.7 ( ); gill slit length 7.9 ( ); isthmus width 3.2 ( ); dorsal-fin height above anal-fin origin 3.8 ( ). Following proportions as percent HL: head width 53.0 ( ); head depth 45.5 ( ); upper jaw length 51.5 ( ); pectoral-fin length 51.5 ( ); pelvicfin length 11.5 ( ); caudal-fin length 37.1 ( ); snout length 27.4 ( ); eye diameter 14.4 ( ); nostril tube length 10.8 ( ); gill slit length 35.7 ( ); interorobital width 6.0 ( ); pectoral base/length ratio 44.3 ( ). Etymology. The new species is named after Dr. M. Eric Anderson, in honour of his many contributions to knowledge of zoarcids. Discussion Ophthalmolycus was defined by Anderson (1994) by the following combination of characters: suborbital bones 7 8, canal with 6 8 pores; gill slit not reaching ventral end of pectoral base; palatopterygoid series well developed; branchiostegal rays 5 6; scales, pseudobranch, pyloric caeca, pelvic fins, lateral line, vomerine and palatine teeth present; vertebrae = The only arguments against including this new species in Ophthalmolycus are the gill slit extension (beyond the ventral end of the pectoral-fin base), and the number of caudal vertebrae (70 74). However none of the aforementioned characters seem to have sufficient weight to prevent the inclusion of this new species in the genus Ophthalmolycus. Besides, other important characters of Ophthalmolycus also given by Anderson (1994) in the description of the genus are present in this new species (e.g., neurocranium elongate, depressed; posterior ramus of hyomandibula not elongate; ceratohyal-epihyal juncture smooth; post-temporal ventral ramus weak or absent; vertebrae asymmetrical anteriorly, excepting O. campbellensis, and black peritoneum). Ophthalmolycus andersoni sp. nov. differs from all congeners (Table 2) by a combination of characters given in its diagnosis and description. Ophthalmolycus andersoni agrees with O. amberensis in meristics and in most morphometric characters, only eye diameter is smaller and pelvic-fin length is shorter in O. andersoni ( and % HL vs and % HL respectively in O. amberensis). However, both species differ in body shape (laterally compressed in O. andersoni, somewhat rounded in cross section in O. amberensis); head shape (nearly triangular in O. andersoni, and ovoid in O. amberensis); lower lateral-line shape (steeply sloping at pectoral-fin base in O. andersoni, descending gradually across abdomen to just above anal-fin origin in O. amberensis); pectoral-fin insertion (uppermost pectoral-fin ray inserted well below body midline in O. andersoni, inserted at body midline in O. amberensis); vertical extension of the pectoralfin (pectoral-fin base extending ventrally to abdomen in O. andersoni, extending ventrally just to ventral 58 Zootaxa Magnolia Press MATALLANAS

5 TABLE 1. Counts and measurements of Ophthalmolycus andersoni sp. nov. Holotype Paratype Paratype UAB-B03BSZ25 UAB-B03BSZ9 UAB-B03BSZ99 Standard length SL (mm) Meristic characters Dorsal-fin rays Anal-fin rays Caudal-fin rays Pectoral-fin rays Pelvic-fin rays Precaudal vertebrae Caudal vertebrae Total vertebrae st dorsal-fin pterygiophore with vertebrae Morphometric characters (% SL) Head length (HL) Head width Head depth Snout length Nostril tube length Eye diameter Pupil diameter Interorbital width (bony margin) Upper jaw length Lower jaw length Predorsal length Tail length Dorsal-fin height above anal-fin origin Body height at anal-fin origin Pectoral-fin length Pectoral-fin base height Pectoral-fin base/pectoral-fin length ratio Pelvic-fin length Caudal-fin length Gill slit length Opercular lobe length Isthmus width Morphometric characters (% HL) Head width Head depth Upper jaw length Lower jaw length to be continued OPHTHALMOLYCUS ANDERSONI SP. NOV. (PISCES) Zootaxa Magnolia Press 59

6 TABLE 1. (continued) Holotype Paratype Paratype UAB-B03BSZ25 UAB-B03BSZ9 UAB-B03BSZ99 Pectoral-fin length Snout length Eye diameter Interorbital (hard) Pelvic-fin length TABLE 2. Main meristic and morphometric characters of the 7 species of Ophthalmolycus. Data taken from the following authors: O. amberensis (Anderson, 1988, 1990a); O. bothriocephalus (Anderson, 1988, 1990a, 2006); O. campbellensis (Andriashev & Fedorov, 1986; Anderson, 1990b); O. chilensis and O. conorhynchus (Anderson, 1992); O. macrops (Gosztonyi, 1977; Anderson & Gosztonyi, 1991). Species O. andersoni O. amberensis O. bothrioc. O. campbell. O. chilensis O. conorhy. O. macrops Meristic Characters Branchiostegal rays Dorsal-fin rays Anal-fin rays Caudal-fin rays Pectoral-fin rays Precaudal vertebrae Caudal vertebrae Total vertebrae st dorsal-fin pterygiophore with vertebrae Postorbital pores 2 (1º4º) 2 (1º4º) 2 (1º4º) 3 (1º3º4º) 1º2º3º4º(5º) 2 (1º4º) 2 (1º4º) Suborbital pores Gill rakers Morphometric (% SL) Head length Head width Predorsal length Preanal length Body height at anal-fin origin Morphometrics (% HL) Head width Upper jaw length Pectoral-fin length Snout length Eye diameter Gill slit length Interorbital (hard) Pelvic-fin length V fin absent unknown to be continued. 60 Zootaxa Magnolia Press MATALLANAS

7 TABLE 2. (continued) Species O. andersoni O. amberensis O. bothrioc. O. campbell. O. chilensis O. conorhy. O. macrops Other characters Middle lateral-line present present present present present present present Lower lateral-line present present absent present present present absent? Gill slit extension vs. beyond it to lower end to middle to lower end to middle to lower end to lower end lower pectoral-fin base Mouth position inferior inferior subterminal terminal subterminal ínferior subterminal Color Lips light black black pale/yellow unknown gray-brown unknown Lining of mouth greyish black black pale/yellow blackish blackish blackish Gill cavity black black black pale/yellow blackish blackish blackish Pectoral fin pale black brown yellow/ brown blackish blackish yellowish profile in O. amberensis); pyloric caeca size (66 % of eye diameter in O. andersoni, nublike in O. amberensis); body color (light brown in O. andersoni, dark brown in O. amberensis); pectoral-fin color (ashcoloured in O. andersoni, darker brown, almost black, in O. amberensis). Ophthalmolycus andersoni differs from O. bothriocephalus by the lower lateral-line (present in O. andersoni vs. absent in O. bothriocephalus), gill slit (extending ventrally beyond lower end of pectoral fin base in O. andersoni vs. to opposite lowermost pectoral-fin ray in largest specimens of O. bothriocephalus or above it in smaller fish), mouth position (inferior in O. andersoni vs. subterminal in O. bothriocephalus). Both species also differ in head shape and pectoral-fin position, and in body shape and color (Table 2). The new species chiefly differs from O. campbellensis in its fewer vertebrae, dorsal and anal-fin rays (Table 2), in postorbital pore pattern (pores 1 & 4 in O. andersoni vs. 1, 3 & 4 in O. campbellensis), vertebral centra (asymmetrical in O. andersoni vs. symmetrical in O. campbellensis), head length ( in O. andersoni vs % SL in O. campbellensis), preanal length ( % SL in O. andersoni vs in O. campbellensis), pectoral-fin length ( % HL in O. andersoni vs in O. campbellensis), eye diameter ( % HL in O. andersoni vs in O. campbellensis); mouth position and gill slit extension are also different in both species (Table 2). Ophthalmolycus andersoni agrees with O. chilensis in meristic characters (Table 2) and in the shape of the lower lateral line. However, the new species differs from the latter species mainly in postorbital pore pattern (pores 1 & 4 in O. andersoni vs. 1, 2, 3 & 4 on left side, and 1 5 on right side in O. chilensis), suborbital pores (6+0 in O. andersoni vs. 6+1 in O. chilensis), gill slit (extending ventrally beyond lower end of pectoral-fin base in O. andersoni vs. to middle of pectoral-fin base in O. chilensis), pyloric caeca development (well developed in O. andersoni vs. small nubs in O. chilensis), mouth position (inferior in O. andersoni vs. subterminal in O. chilensis), body color (light brown not uniform in O. andersoni vs. uniform blackish brown in O. chilensis). The new species differs from O. macrops in branchiostegal rays (6 in O. andersoni vs. 5 in O. macrops), caudal vertebrae (70 74 in O. andersoni vs in O. macrops), first dorsal-fin pterygiophore (associated with vertebrae 4 or 5 in O. andersoni vs. with 8 in O. macrops), lower lateral-line (present in O. andersoni vs. absent in O. macrops), eye diameter ( % HL in O. andersoni vs in O. macrops); mouth position, gill slit extension, and color are different in both species (Table 2). Finally O. andersoni differs from O. conorhynchus in having pelvic fins (absent in O. conorhynchus), suborbital pore pattern (6+0 in O. andersoni vs in O. conorhynchus), pyloric caeca (well developed in O. andersoni vs. small nubs in O. conorhynchus); mouth position, gill slit extension, and color are different in both species (Table 2). OPHTHALMOLYCUS ANDERSONI SP. NOV. (PISCES) Zootaxa Magnolia Press 61

8 Acknowledgements I thank the scientific team, the captain, crew and UTM technicians of the R/V Hespérides for their help during the BENTART-03 cruise, on which the type specimens were captured. I am also grateful to C. Benito (Manageress, Servei de Radiosòtops, Facultat de Biologia, Universitat de Barcelona, Spain) for the X-rays, and J. Corbera for the illustrations. I thank my daughter Muriel for the English revision of the manuscript. The comments of M.E. Anderson and those of two anonymous referees greatly improved the manuscript. The BENTART-03 cruise was supported by the Spanish Antarctic Programme (CICYT). This study was supported by a grant from the Ministerio de Educación y Ciencia, Spain: Estudio taxonómico de los Zoarcidae (Teleostei: Perciformes) del Mar de Bellingshausen (Océano Antártico), (CLG E/ ANT). References Anderson, M.E. (1982) Revision of the fish genera Gymnelus Reinhardt and Gymnelopsis Soldatov (Zoarcidae), with two new species and comparative osteology of Gymnelus viridis. National Museum, Natural Science Publications, Zoology, 17, Anderson, M.E. (1988) Studies on the Zoarcidae (Teleostei: Perciformes) of the southern hemisphere. I. The Antarctic and subantarctic regions. Antarctic Research Series, 47, Anderson, M.E. (1990a) Zoarcidae. Eelpouts. In: Gon, O. & Heemstra, P.C. (Eds.), Fishes of the Southern Ocean, J.L.B. Smith Institute of Ichthyology, Grahamstown, pp Anderson, M.E. (1990b) Studies on the Zoarcidae, (Teleostei: Perciformes) of the southern hemisphere. III. The southwestern Pacific. J. L. B. Smith Institute of Ichthyology, Special Publication, 50, Anderson, M.E. (1992) Studies on the Zoarcidae (Teleostei: Perciformes) of the southern hemisphere. VI. Review of the genus Ophthalmolycus Regan, 1913, with description of a new species from Chile. J.L.B. Smith Institute of Ichthyology, Special Publication, 53, Anderson, M.E. (1994) Systematics and osteology of the Zoarcidae (Teleostei: Perciformes). J. L. B. Smith Institute of Ichthyology; Ichthyological Bulletin, 60, Anderson, M.E. (2006) Studies on the Zoarcidae of the Southern hemisphere. X. New records from western Antarctica. Zootaxa, 1110, Anderson, M.E. & Fedorov, V.V. (2004) Family Zoarcidae Swainson 1839, eelpouts. California Academy of Sciences, Annotated Checklist of Fishes, 34, Anderson, M.E. & Gosztonyi, A.E. (1991) Studies on the Zoarcidae (Teleostei: Perciformes) of the southern hemisphere. IV. New records and a new species from the Magellan Province of South America. J. L. B. Smith Institute of Ichthyology, Ichthyological Bulletin, 55, Andriashev, A.P. & Fedorov, V.V. (1986) First discovery of Zoarcidae in New Zealand waters. Journal Ichthyology, 26, Eastman, J.T. (2005) The nature of the diversity of Antarctic fishes. Polar Biology, 28, Gosztonyi, A.E. (1977) Results of the research cruises of FRV Walter Herwig to South America. XLVIII. Revision of the South American Zoarcidae (Osteichthyes, Blennioidei) with the description of three new genera and five new species. Archiv Fischerei wissenschaft, 27, Gosztonyi, A.E. (1988) The intercalar bone in the eelpout Family Zoarcidae (Osteichthyes). Zoologischer Anzeiger, 3 4, Matallanas, J. (2008) Description of Gosztonyia antarctica, a new genus and species of Zoarcidae (Teleostei: Perciformes) from the Antarctic Ocean. Polar Biology, 32, Matallanas, J. & Olaso, I. (2007) Fishes of the Bellingshausen Sea and Peter I Island. Polar Biology, 30, Moeller, P.R. & Stewart, A.L. (2006) Two new species of eelpouts (Teleostei, Zoarcidae) of the genus Seleniolycus from the Ross Dependency, Antarctica. Zootaxa, 1376, Regan, C.T. (1913) The Antarctic fishes of the Scottish National Antarctic Expedition. Transactions of the Royal Society of Edinburgh, 49, , pl Zootaxa Magnolia Press MATALLANAS

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AUSTRALIAN MUSEUM SCIENTIFIC PUBLICATIONS Anderson, M. Eric, 1994. Studies on the Zoarcidae (Teleostei: Perciformes) of the southern hemisphere. VII. A new species of Dieidolycus Anderson, 1988 from the