Brasilochondria riograndensis gen. nov., sp. nov. (Copepoda, Chondracanthidae) a parasite of flounders of Rio Grande do Sul State, Brazil

Brasilochondria riograndensis gen. nov., sp. nov. (Copepoda, Chondracanthidae) a parasite of flounders of Rio Grande do Sul State, Brazil¹

Vernon E. Thatcher^I; Joaber Pereira Júnior^II

^IDepartamento de Zoologia, Universidade Federal do Paraná. Caixa Postal 19020, 81531-980 Curitiba, Paraná, Brasil.Research Fellow of the CNPq

^IIDepartamento de Ciências Morfobiológicos, Fundação Universidade Federal do Rio Grande, Rio Grande do Sul, 96200-050 Rio Grande, Rio Grande do Sul, Brasil. E-mail: [e-mail]

ABSTRACT

Brasilochondria riograndensisgen. nov., sp. nov. (Copepoda, Chondracanthidae) a parasite of the flounder, Paralichthys orbignyanus (Valenciennes, 1839), is described. The new genus has a spherical head a post-mandibular "neck" and two pairs of modified biramous legs. In these respects, it resembles Argentinochondria patagonensis Etchegoin, Timi & Sardella, 2003. In the Argentine genus, however, the bulbous head has a medial constriction and the posterior of the female lacks the lateral extensions that are present in the new genus. Pseudolernentoma brasiliensis Luque & Alves, 2003, also resembles the new genus but it lacks the lateral extensions of the trunk and the latter is cylindrical rather than flat. The second leg of the new genus is small and the endopod is shorter than the exopod. The other two genera have large second legs with subequal rami.

Key words: Copepod parasite, chondracanthid, Southern Brasil, South Atlantic.

RESUMO

Brasilochondria riograndensisgen. nov., sp. nov. (Copepoda, Chondracanthidae), um parasito do linguado, Paralichthys orbignyanus (Valenciennes, 1839), é descrito. O novo gênero tem uma cabeça esférica, um "pescoço" pós-mandíbular e dois pares de pernas que são birremes e modificados na fêmea. Nestes aspectos, ela parece com Argentinochondria patagonensis Etchegoin, Timi & Sardella, 2003. Nesta, no entanto, a cabeça é esférica com uma constrição medial e na parte posterior do tronco faltam as extensões póstero-laterais que o novo gênero possui. Pseudolernentoma brasiliensis Luque & Alves, 2003, é também parecido com o novo gênero, mas carece das extensões póstero-laterais e o mesmo tronco é cilíndrico em vez de achatado. A segunda perna no novo gênero é pequena e o endopodito é mais curto que o exopodito. Nos outros dois gêneros, as segundas pernas são grandes e os ramos são sub-iguais.

Palavras chave: Copépodo parasito, chondracanthídeo, Sul do Brasil, Atlántico Sul.

Chondracanthidae is a family of copepods found parasitizing marine fishes throughout the world. YAMAGUTI (1963) listed 37 genera and 133 species in this family with a majority of species ascribed to Acanthochondria Oakley, 1927 (48) and Chondracanthus Delaroche, 1811 (27). Since that time, a few additional genera and species have been described. HO (1994) offered a key to 41 genera of chondracanthids. BOXSHALL & MONTÚ (1997) listed only two representatives of this family for Brazil, namely, Blias prionoti Kroyer, 1863, and Chondracanthus merluccii (Holten, 1802). Recently, ETCHEGOIN et al. (2003) described a new genus and species, Argentinochondria patagonensis, from a marine fish of Patagonia. LUQUE & ALVES (2003) proposed a new genus and species that they called, Pseudolernentoma brasiliensis from a marine fish of Rio de Janeiro State, Brazil. ALVES et al. (2003) described a new species, Acanthochondria triangularis from a Brazilian coastal fish. The present paper describes a new genus and species of Chondracanthidae from flounders of Rio Grande do Sul State, Brazil.

MATERIAL AND METHODS

Fish hosts were netted in the sea near Rio Grande in Rio Grande do Sul State, Brazil. The copepods were removed from the gills and the inner sides of the opercula by means of dissecting needles and fixed in 70% ethanol. The specimens were cleared in pure phenol for study. Digital photographs were made at five megapixels. Measurements were obtained with a measuring ocular and are expressed in microns (µm) unless indicated as millimeters (mm). Extremes are followed by the means in parentheses.

RESULTS

Brasilochondria gen. nov.

Female: Body consisting of a spherical cephalothorax, elongate, cylindrical, post-mandibular "neck" and flattened trunk. Head composed of cephalosome only; "neck" formed from first two pedigerous segments; trunk extended postero-laterally on either side. Leg 1 small, immediately behind head, biramous, rami flattened; leg 2 just anterior to trunk, biramous. Egg sacs elongate, cylindrical, multiseriate.

Male: Dwarf, with expanded cephalothorax; body segmentation indistinct; genitoabdomen terminates in two spiniform caudal rami. Antennule short and cylindrical; antenna uncinate and robust. Legs 1 and 2 represented by simple lobes.

Type and only species: Brasilochondria riograndensis sp. nov.

Brasilochondria riograndensis sp. nov.

Figs 1-21

Female (10 measured: Figs 1-9, 17-18, 20-21) Total length, 11.4-16.4 (13.6) mm; maximum width at mid-level of trunk, 2.1-3.4 (2.8) mm. Cephalothorax spherical, 1.39-2.46 (1.90) mm in diameter, bearing antennae and mouthparts; antennule short, cylindrical with few spines terminally, 210-280 (252) long and 50-100 (76) in diameter: antenna hook-like, 260-325 (294) long by 140-165 wide. Mouthparts (Figs 5-7) of typical poecilostome form. Maxilliped of three articles. Neck cylindrical, expanding posteriorly, 462-616 (519) in diameter and 4.62-7.82 (5.62) mm in length. Neck bearing two pairs of modified legs; leg 1 of two flattened rami, endopod 190-325 (240) long and 85-175 (128) wide; exopod 180-350 (256) long by 100-175 (165) wide: leg 2 of two tapered, cylindrical rami; endopod 125-225 (173) long and 55-90 (73) wide; exopod 290-1263 (969) long by 75-462 (308) wide. Trunk broadly flattened, terminating in a tapered lateral extension on either side and a medial caudal projection, measures 5.2-6.7 (6.0) mm long and 2.1-3.4 (2.8) mm wide. Caudal cone (Figs 18, 21) 500-662 (600) long by 425-539 (478) wide at base. Egg sac elongate, slender, 5.0-5.7 (5.6) mm long and 115-500 (462) in diameter.

Male (five measured: Figs 10-16). Body cylindrical, tapering anteriorly and posteriorly segmentation indistinct, 450-750 (625) long and 250-447 (374) in height. Antennules small, bisegmented (Fig. 14); antennae strong, hook-like,used to attach to caudal projection of female. Mouthparts (Figs 11-16) typically poecilostome, maxilliped of four articles.

Host. Paralichthys orbignyanus (Valenciennes, 1839).

Site. Interior of the mouth with the cephalothorax embedded in the skin.

Locality. Atlantic Ocean near Rio Grande, RS, Brazil.

Type material. Holotype female, 10 paratype females and four paratype males deposited in the Crustacean Collection of the Instituto Nacional de Pesquisas da Amazônia, Manaus, AM, Brazil.

Etymology. The generic name refers to the country of origin and the specific name to the state.

DISCUSSION

Brasilochondria gen. nov. clearly belongs to the subfamily Chondracanthinae as defined by KABATA (1979) because it has a post-mandibular neck, an expanded cephalothorax and two pairs of modified legs in the female. The new genus most resembles Argentinochondria Etchegoin, Timi & Sardella, 2003,and Pseudolernentoma Luque & Alves, 2003, but differs from these in several important respects. The new genus has a completely spherical cephalothorax without projections or constrictions. Also, the trunk is flattened (not cylindrical) and is provided with postero-lateral flat extensions. Furthermore, the caudal projection (Fig. 21) is unlike those of the other genera and leg 2 is short with unequal rami (not large with subequal rami).

ACKNOWLEDGEMENTS

The authors are grateful to Dr. Ricardo Robaldo (FURG), and Dr. Walter P. Boeger (UFPR), for making the specimens of this new genus of copepod available for study.

Received in 13.IV.2004; accepted in 15.VII.2004.

• ALVES, D.R., J.L. LUQUE & A.R. PARAGUASSÚ. 2003. Acanthochondria triangularis sp. nov. (Copepoda, Poecilostomatoida, Chondracanthidae) parasitic on Urophycis brasiliensis and U. mystaceus (Osteichthys, Phycidae) from the Southern Brazilian coastal zone. Acta Parasitologica, Warsaw, 48: 19-23.
• BOXSHALL, G.A. & M. MONTÚ. 1997. Copepods parasitic on Brazilian coastal fishes: a handbook. Nauplius, Porto Alegre, 5: 1-225.
• ETCHEGOIN, J.A.; J.T. TIMI & N.H. SARDELLA. 2003. Argentinochondria patagonensis n. gen., sp. nov. (Copepoda: Chondracanthidae) parasitic on Genypterus brasiliensis (Pisces: Ophidiidae) from Patagonia, Argentina. Journal of Parasitology, Lawrence, 89: 701-704.
• HO, J.S. 1994. Chondracanthid copepods (Poecilostomatoida) parasitic on Japanese deep-sea fishes, with a key to the Genera of the Chondracanthidae. Journal of Natural History, London, 28: 505-517.
• KABATA, Z. 1979. Parasitic Copepoda of British Fishes. London, The Ray Society, 468p.
• LUQUE, J.L & D.R. ALVES. 2003. Pseudolernentoma brasiliensis n. g., n. sp. (Copepoda: Poecilostomatoida: Chondracanthidae) parasitic on Genypterus brasiliensis (Osteichthyes, Ophidiidae) from off the state of Rio de Janeiro, Brazil. Systematic Parasitology, Amsterdam, 56: 195-199.
• YAMAGUTI, S. 1963. Parasitic Copepoda and Branchiura of fishes. New York, Interscience Publishers, 1104p.

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Contribuição número 1508 do Departamento de Zoologia, Universidade Federal do Paraná.

Publication Dates

• Publication in this collection
  27 Apr 2006
• Date of issue
  Sept 2004

History

• Accepted
  15 July 2004
• Received
  13 Apr 2004