A new species of Tormopsolus (Digenea: Acanthocolpidae) parasite of Genypterus brasiliensis (Teleostei: Ophidiidae) from the Brazilian coast

Tormopsolus brasiliensis sp. nov. is described from the intestine of Genypterus brasiliensis Regan, 1903, from Brazil. The new species is characterized mainly by having an almost square terminal oral sucker, a pharynx of the same size or larger than the oral sucker, and testes very close to each other and without vitelline follicles between them. Tormopsolus brasiliensis sp. nov. is most closely related to T. lintoni Caballero, 1952, sharing with the latter the space between the gonads and the distribution of the vitelline fields. It differs from that species by the lack of a space between the gonads and the absence of vitelline follicles between the testes; by the smaller distance between the oral and ventral suckers; by the presence of a wide ejaculatory duct armed with spines; a wide metraterm, almost the same size of the cirrus-sac; and by the shape and terminal position of the oral sucker. Specimens recovered already dead showed distinct differences to the well-fixed, freshly-collected material and are these differences are enumerated. Acanthocolpus brasiliensis of ALVES et al. (2002a,b) is considered synonym of T. brasiliensis sp. nov.


MATERIAL AND METHODS
Between October 2002 and September 2003 38 specimens of G. brasiliensis, 54.5-93.0cm total length, were examined.Specimens were purchased in fish markets in the municipalities of Niterói and Rio de Janeiro, state of Rio de Janeiro, Brazil.After collection, the fish were transported in an insulated box filled with ice to the Laboratório de Helmintos Parasitos de Vertebrados do Instituto Oswaldo Cruz (IOC), Fundação Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, where they were identified according to FIGUEIREDO & MENEZES (1978).Specimens were subsequently necropsied and their organs were analyzed.The internal organs were transferred to the Petri dishes with a saline solution at 0.65% NaCl and observed through the stereomicroscope.The digeneans collected from the intestine were cold fixed in AFA, without compression, stained with Langeron's alcoholic acid carmine, dehydrated in an ethyl alcohol series, cleared in beechwood creosote and finally mounted in Canada balsam as permanent slides.The taxonomic classification is in 1 Laboratório de Helmintos Parasitos de Vertebrados, Instituto Oswaldo Cruz. Avenida Brasil 4365, 21045-900 Rio de Janeiro, Rio de Janeiro, Brazil. E-mail: knoffm@ioc.fiocruz.br 2 Laboratório de Helmintos Parasitos de Peixes, Instituto Oswaldo Cruz. Avenida Brasil 4365, 21045-900 Rio de Janeiro, Rio de Janeiro, Brazil. E-mail: berenice@ioc.fiocruz.brABSTRACT.Tormopsolus brasiliensis sp.nov. is described from the intestine of Genypterus brasiliensis Regan, 1903, from Brazil.The new species is characterized mainly by having an almost square terminal oral sucker, a pharynx of the same size or larger than the oral sucker, and testes very close to each other and without vitelline follicles between them.
Tormopsolus brasiliensis sp.nov. is most closely related to T. lintoni Caballero, 1952, sharing with the latter the space between the gonads and the distribution of the vitelline fields.It differs from that species by the lack of a space between the gonads and the absence of vitelline follicles between the testes; by the smaller distance between the oral and ventral suckers; by the presence of a wide ejaculatory duct armed with spines; a wide metraterm, almost the same size of the cirrus-sac; and by the shape and terminal position of the oral sucker.Specimens recovered already dead showed distinct differences to the well-fixed, freshly-collected material and are these differences are enumerated.Acanthocolpus brasiliensis of ALVES et al. (2002a,b) is considered synonym of T. brasiliensis sp.nov.KEY WORDS.Marine fish; South America; taxonomy; Tormopsolus brasiliensis sp.nov.; Trematoda.
accordance with BRAY (2005).The whole mounts were observed at the Olympus BX 41 bright field microscope and measured.Measurements, unless otherwise stated, are given in micrometers, and quoted as a range with their means between parentheses.Figures were drawn with the aid of a drawing tube.Photographies were taken using a Zeiss Axiophot bright field microscope.Parasite indexes follow the concepts of BUSH et al. (1997).Specimens studied are deposited in the "Coleção Helmintológica do Instituto Oswaldo Cruz" (CHIOC), Brazil.

DISCUSSION
The main morphological characters of the new species are as follows: the almost square terminal oral sucker; the pharynx subequal in size to or larger than the oral sucker; and gonads very close to each other, without vitelline follicles between them.None of the previously described species of Tormopsolus have an almost square terminal oral sucker.In combination, the characters mentioned above are sufficient to differentiate the new species from all other species of the genus.Those (10) species have vitelline follicles between the gonads, and the fields may interrupted or not at the level of the ovary and testes (BRAY & CRIBB 2001, EL-LABADI et al. 2006).
Tormopsolus brasiliensis sp.nov. is most closely related to T. lintoni Caballero, 1952, described from the intestine of Enchelyopus cimbrius (Linnaeus, 1766), from Massachusetts, USA.It differs from that species by the following features: the lack of a space and vitelline follicles between the testes; the smaller distance between the oral and ventral suckers; the presence of a wide ejaculatory duct armed with spines; a wide metraterm that is longer than the ejaculatory duct and almost the same length as the cirrus-sac; and the shape and terminal position of oral sucker.
Mostly, the specimens that were recovered already dead showed distinct differences when compared with the well-fixed, freshly-collected material.Specimens of the first are very long and narrow, with fewer spines on the tegument and in the ejaculatory duct, and a greater distance between the ventral sucker and the ovary and between the ovary and the anterior testis.Main measurements based on seven specimens: Body 2.95-4.67(3.62) x 0.12-0.27mm (0.19 mm); oral sucker 110-165 ( 146  State.We had the opportunity to study a specimen previously analyzed by ALVES et al. (2002a,b) deposited in the CHIOC n. 34569 and have verified that it is similar to those specimens that had been collected already dead (see above).Based on this similarity, we have concluded that it belongs to our new species and we consider it a synonym of T. brasiliensis sp.nov.