Helminthological records of six-banded Armadillos Euphractus sexcinctus ( Linnaeus , 1758 ) from the Brazilian semi-arid region , Patos county , Paraíba state , including new morphological data on Trichohelix tuberculata ( Parona and Stossich , 1901 ) Ortlepp , 1922 and proposal of Hadrostrongylus r

This work aimed to evaluate the gastrointestinal helminthfauna composition of six-banded armadillos from the Brazilian semi-arid region. Gastrointestinal contents of six road-killed adult animals from Patos County, Paraíba State, were analyzed. Six species of nematodes, comprising five genera and four families, were recovered from the analyzed animals. New morphological data on Trichohelix tuberculata is given, along with a new taxonomical proposal for Hadrostrongylus ransomi (Travassos, 1935) n. comb. This is the first record for parasitic helminths in this host from the Brazilian semi-arid.


Introduction
Six-banded armadillos Euphractus sexcinctus (Linnaeus, 1758) Wagler, 1830 (Xenarthra Cope, 1889: Dasypodidae Gray, 182) are classified among the subfamily Euphractinae Winge, 1923, along with the genus Chaetophractus Fitzinger, 1871 and closely related to the Tolypeutinae Gray, 1865 (Delsuc, 2002).These ar-madillos are distributed in most of the central and eastern Brazilian territory, Paraguay, Uruguay and northern Argentina.Their occurrence has also been reported in Suriname and east of the Andes, suggesting a wider distribution of this species (Nowak, 1999;Beresca and Cassaro, 2001).helminths fixed and conserved in warm Railliet and Henry solution and stored in labelled vials.
After that, the vials were submitted to the Parasitic Diseases Laboratory "Prof.Dr. Orlando Ferrari" of the Department of Preventive Veterinary Medicine and Animal Reproduction, FCAV/Unesp, Jaboticabal, São Paulo state, for taxonomic identification.

Study area
The Brazilian semi-arid is an area of about 800,000 km 2 , spread over ten States, mainly in the Northeastern region of the country.The pronounced environmental heterogeneity, allied with the uniqueness of certain ecotopes, may contribute to a great richness of the invertebrate fauna (Silva et al., 2003).
In Patos County (Figure 1), the temperature ranges from 24 to 28 °C, with an average pluviometric index of 681.6 mm (Costa Silva et al., 2003).There is a predominance of the hyperxerophyle Caatinga scrub vegetation, due to the elevated hydric deficiency over the year.The physiographic area is close to Serra de Santa Luzia, a Caatinga prioritary area for invertebrate conservation, because of its richness of species (Silva et al., 2003).

Parasitological methods
For morphological studies, the helminths were clarified in 80% acetic acid and beechwood creosote.Measurements of morphological characters, expressed in millimetres, were taken from ten mature nematodes of each sex and were expressed as range followed by sample mean and coefficient of variation in parenthesis.Synlophe studies were conducted when needed and were done according to the technique described by Durette-Desset (1969).Drawings were made with a camera lucida attached to a Carl-Zeiss ® microscope.After total The six-banded armadillos occur mainly in open areas such as savannahs and scrubs, but they can also inhabit dense forests and jungles (Nowak, 1999).In the Brazilian semi-arid, E. sexcinctus is the armadillo species with the widest area of occurrence, followed by Dasypus novemcinctus Linnaeus, 1758 (Silva et al., 2003).Preferentially herbivorous, E. sexcinctus may scavenge for dead animals and also eat little vertebrates and invertebrates, denoting generalist food habits, in contrast with the more specialist sympatric species D. novemcinctus (Bonato, 2002).
Despite the fact that six-banded armadillos are a common species in Brazil and Argentina (Nowak, 1999;Bonato, 2002), little is known regarding the helminthfauna of these animals.This study provides helminthological data along with mean intensity and range of intensity, as well as new morphological data for Trichohelix tuberculata (Parona andStossich, 1901) Ortlepp, 1922 and a new taxonomical proposal: Hadrostrongylus ransomi n. comb.Type genus : Trichohelix Ortlepp, 1922Remarks: Durette-Desset (1983), in an attempt of the organization of the Molineidae Durette-Desset and Chabaud, 1977 family mainly according to their synlophe pattern and female reproductive system, allocated the single-specific genus Trichohelix Ortlepp, 1922 along the Anoplostrongylinae Chandler, 1938.However, data obtained in this study permit us to reconsider the taxonomical positioning of this taxon in the subfamily Trichohelicinae Travassos, 1935, due to its unique synlophe pattern and female reproductive system morphology, representing an autapomorphy not observed in other Anoplostrongylinae species.

Trichohelix tuberculata (Parona and Stossich, 1901) Ortlepp, 1922
Diagnosis: Strongly spiraled nematodes with striated cephalic dilatation, reddish in color in situ.Cuticle has inflations seen in all body length.Filariform esophagus, slightly thicker on distal third.Nervous ring situated on the middle part of the esophagus and the excretory pore opening is next to the esophageal-intestinal junction.Cervical papillae are absent (Figure 2).
The synlophe is formed by many ridges asymmetrically disposed with variable size.The ventral face of the nematode body has three to four striated ventral longitudinal ridges, depending on the sectioned body region (Figures 3 and 4).

Results and Discussion
All studied armadillos were parasitized by two nematode species at least, whilst cestodes, trematodes, and acanthocephalans were not observed.Five nematodes, comprising four genera and three families were diagnosed (Table 1).Among these, new morphological and taxonomical data were obtained for two nematode species, Trichohelix tuberculata (Parona and Stossich, 1901) Ortlepp, 1922 and Hadrostrongylus ransomi (Travassos, 1935) n. comb.
Remarks: Travassos (1937) describes this species as parasite of C. unicinctus and D. novemcinctus from Rio de Janeiro state, Brazil.However, the author mentions that some morphological characteristics set this species apart of other congeneric species, suggesting that a better taxonomical replacement should be done.Hoppe and Nascimento (2007), based on a nematode species found parasitizing large intestine of D. novemcinctus from the Brazilian Pantanal wetlands, erect the genus Hadrostrongylus and describe H. speciosum, also found parasitizing E. sexcinctus from the same physiographic region (Hoppe et al., 2006).Until now, there are no reports of co-parasitism by H. speciosum and H. ransomi, suggesting that these congeneric species could not be two morphotypes of a single polymorphic species.H. ransomi may be easily differentiated from excretory pore situated 0.1720 -0.2046 (0.1720 ± 0.0156) and 0.3441 -0.3767 (0.3627 ± 0.0129) distant from anterior ending, respectively.
They are didelphic and prodelphic, with vulvar opening close to anus (Figure 9), located 0.2744 -0.3518 (0.3090 ± 0.0299) and 0.0454 -0.074 (0.0511 ± 0.0109) from tail tip, respectively.Cranially to the vulvar opening there is a strongly striated cuticular dilatation.The posterior branch of the reproductive tract, shorter than the anterior branch, is curved after the vagina vera sphincter, bending cranially towards the anterior body ending.The rounded-tipped tail of the females is abruptly tapered.Eggs are ellipsoid, smooth-shelled and non-morulated in utero.
Types: One male and one female (Paratypes) are deposited under Collection number CHIOC 35525, as wet mounts.
Remarks: Previous synlophe studies of T. tuberculata (Navone, 1987) showed absence of crests.However, this author used paraffin-embedded histological sections that may have lead to misinterpretation.

Hadrostrongylus ransomi nov. comb.
Diagnosis : Trichostrongyloidea Cram, 1927, Molineidae Durette-Desst and Chabaud, 1977, Anoplostrongylinae Chandler, 1938.Slender, non-spiraled nematodes, with finely striated cephalic vesicle.Cervical papillae are absent.Short, claviform esophagus, thickened next to the base.Nerve ring on mid-body of esophagus, while the excretory pore opening situates after the esophageal-intestinal junction (Figure 10).Synlophe on mid-body section is formed by four main ventral crests and ten secondary smaller crests all over the nematode body (Figure 11), with ventral-dorsal orientation.Males with bilobed copulatory bursa, strongly attached to ventral body surface, with bursal rays type 2-1-2.Small pre-bursal papillae present.Rays 2 and 3 originate from common trunk and diverge next to distal third part, reaching the bursal margin.Rays 4, 5 and 6 share the same trunk, diverging on their proximal third part.The short, fine-tipped, ray 4 does not reach the bursal margin.Externo-dorsal rays rises next to body insertion of common dorsal trunk, and the dorsal ray

Further Considerations
Contrary to previous observations regarding E. sexcinctus helminthfauna by Lombardero andMoriena (1977), andFujita et al. (1995), no gastric helminths have been observed in this work.Those authors' studies were based on specimens collected from physiographic areas much different from that of the present work, which is hotter and drier than theirs.This fact may also explain the minor diversity of the obtained helminth species.The species diversity is also inferior to that observed in D. novemcinctus from the Brazilian Pantanal wetlands (Hoppe and Nascimento, 2007), and Aspidodera fasciata (Schneider, 1866) is the only species diagnosed in both Biomes.
Ancylostoma caninum (Ercolani, 1859) infection observed in one armadillo may be due cross infection with infective forms originated from sympatric carnivores, as only three nematodes have been found in one host.Despite the great resemblance of A. caninum with the armadillo ancylostome Ancylostoma martinagliai Mönnig, 1931(Santa-Cruz et al., 1997), these species can be separated by the buccal capsule morphology, discarding any possibilities of misdiagnosis.
This study is the first record for parasitic helminths in E. sexcinctus from Paraíba state, representing a new locality report for these species, as well as new host records for H. ransomi, previously found on Brazilian D. novemcinctus and C. unicinctus, according to Vicente et al. (1997), contributing to a better knowledge of the Caatinga biodiversity.