FOLIA PARASITOLOGICA 45: 230-232, 1998

Description of a new species of (: ) from Larus dominicanus (Aves: Laridae) in Buenos Aires coast, Argentina

Florencia Cremonte1,2 and Sergio Roberto Martorelli1,3

1Laboratorio de Helmintos, Centro de Estudios Parasitológicos y de Vectores (UNLP/CONICET), 1900 La Plata, Argentina; 2Comisión de Investigaciones Científicas de la provincia de Buenos Aires (CIC); 3Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)

Key words: Digenea, Microphallidae, Maritrema orensensis sp. n., Larus dominicanus, Argentina

Abstract. Maritrema orensensis sp. n. (Digenea: Microphallidae) from Balneario Orense, Buenos Aires province, Argentina, is described. Adults of M. orensensis were collected from the intestine of the kelp gull Larus dominicanus Lichtenstein, 1823 (Aves: Laridae) and differ from adults of other related species, principally, in the shorter intestinal caeca and the incomplete ring of vitelline follicles.

Only five species of the genus Maritrema Nicoll, means and standard deviations in parentheses. 1907 (Digenea: Microphallidae) have been previously reported from South America. These include two RESULTS species from Brazil: M. nicolli Travassos, 1920 in Daphila bahamensis (Aves: Anatidae) and M. Maritrema orensensis sp. n. Figs. 1, 2 pulcherrima Travassos, 1929 in the digestive tract of Description (based on 15 specimens, measurements Didelphis aurita (Mammalia: Didelphidae) (Deblock on 10): Body elongate, linguiform, 0.38-0.51 long and 1972); one species from Peru: M. bravoae Caballero et 0.19-0.27 wide at level of testes (0.43 ± 0.031 × 0.23 ± Ibañez, 1970 in Anthus chii peruvianus (Aves: 0.026). Body surface fully covered by tegumental Passeriformes) (Caballero and Ibañez 1970); one spines. Oral sucker subterminal 0.034-0.053 × 0.030- undescribed species from Venezuela in Tringa 0.050 (0.041 ± 0.006 × 0.027 ± 0.012); acetabulum melanoleuca (Aves: Scolopacidae) (Mc Neil et al. equatorial, 0.038-0.044 (0.042 ± 0.002) of diameter. 1996); and one species from Argentina: M. bonaerensis Sucker ratio 1 : 1.02. Prepharynx 0.011-0.047 long Etchegoin et Martorelli, 1997 in the intestine of Larus (0.027 ± 0.012); pharynx muscular 0.026-0.037 × 0.020- atlanticus and L. maculipennis (Aves: Laridae) 0.032 (0.029 ± 0.004 × 0.024 ± 0.004). Oesophagus (Etchegoin and Martorelli 1997). 0.021-0.042 long (0.031 ± 0.009); intestinal caeca: left This situation contrasts with numerous species of this intestinal caecum 0.080-0.122 long and 0.008-0.027 genus reported in other parts of the world, illustrating wide (0.100 ± 0.017 × 0.019 ± 0.008), right intestinal the lack of information from South America. The aims caecum 0.074-0.119 long and 0.008-0.026 wide (0.098 of this paper are to describe a new species of Maritrema ± 0.019 × 0.016 ± 0.008), terminating in vicinity of Nicoll, 1907 from the kelp gull Larus dominicanus anterior border of cirrus-sac. Testes oval, symmetrical, Lichtenstein, 1823 (Aves: Laridae) and to compare it postovarian; left testis 0.027-0.069 long and 0.034- with related ones. 0.079 wide (0.046 ± 0.015 × 0.056 ± 0.013), right testis 0.027-0.066 long and 0.041-0.095 (0.045 ± 0.013 × 0.06 MATERIALS AND METHODS ± 0.014). Cirrus-sac nonmuscular, thin-walled, arched, A kelp gull Larus dominicanus was found dead in Bal- 0.093-0.165 long and 0.034-0.077 (0.136 ± 0.022 × neario Orense (38°42’S; 59°47’W), a rocky coast in the 0.049 ± 0.013), occupying space between intestinal Buenos Aires province, Argentina. After dissection, the caeca and acetabulum. Seminal vesicle oval, located at digestive tract was fixed in the field with 10% formalin. In the posterior end of cirrus-sac, 0.035-0.072 × 0.021-0.037 laboratory, adult digeneans were removed from the intestine (0.048 ± 0.01 × 0.030 ± 0.005). Prostatic cells and stored in 70% alcohol, stained with Semichon’s numerous, 0.009-0.011 (0.010 ± 0.01) in diameter. Pars acetocarmine, mounted in Canada balsam, and studied under prostatica not evident. Ductus ejaculatorius slightly the microscope. The drawings were made with the aid of a convoluted. Cirrus invaginated, unspined, 0.058-0.074 × camera lucida. All measurements are given in mm, with the 0.021-0.025 (0.066 ± 0.008 × 0.023 ± 0.002). Ovary

Address for correspondence: F. Cremonte, Laboratorio de Helmintos, CEPAVE, Calle 2 No. 584, 1900 La Plata, Argentina. Phone: ++54 21 233471; Fax: ++54 21 232327; E-mail: [email protected]

230 Cremonte and Martorelli: Maritrema orensensis sp. n.

Fig. 2. Detail of the terminal genitalia of Maritrema orensensis sp. n., dorsal view. Scale bar = 0.05 mm; c - cirrus; cs - cirrus-sac; e - eggs; gp - genital pore; m - metraterm; ov - ovary; pc - prostatic cells; sv - seminal vesicle; u - uterus; v - vitelline follicles. Scale bar = 0.05 mm.

DISCUSSION Out of the species listed in Deblock’s keys (Deblock 1971), this new species is most similar to Maritrema gratiosum Nicoll, 1907, but it differs in having shorter intestinal caeca (not reaching testicular fields), an arched cirrus-sac and no evidence of a pars prostatica. With respect to the species described after the classification of Deblock (1971) and according to Gracenea et al. (1993), M. orensensis would belong to the group formed by the species morphologically Fig. 1. Adult of Maritrema orensensis sp. n., ventral view. similar to M. acadiae Swales, 1933. This group, which Scale bar = 0.1 mm. has a simple genital atrium and a non-spinous cirrus, includes M. laricola Ching, 1963, M. paracadiae Ching, trilobated, middle-dextral, anterior border overlapping 1974 and M. chiriacae Deblock, 1975. These four acetabulum, 0.034-0.079 × 0.034-0.072 (0.050 ± 0.012 species differ from the new species in that they have × 0.053 ± 0.01). Laurer’s canal and seminal receptacle longer intestinal caeca (reaching the acetabulum) and not seen. Uterus extending from anterior edge of testes the vitellarium forming a complete ring (Ching 1963, until end of body. Eggs numerous, operculated, 0.012- 1974, Deblock 1975, Deblock and Canaris 1992). 0.016 × 0.074-0.011 (0.015 ± 0.001 × 0.010 ± 0.003). Following to Gracenea et al. (1993) there is a group Short metraterm muscular. Genital pore sinistral to of species without characteristics in common. This acetabulum. Vitellarium in an inverted U-shaped includes M. pacifica Ching, 1974, M. majestova Xiao- incomplete ring between testes and ovary. Lin, 1976 and M. feliui Gracenea, Montoliu et Deblock, T y p e h o s t : Larus dominicanus Lichtenstein, 1823 (Aves: 1993. M. orensensis differs from M. pacifica in having Laridae). shorter intestinal caeca (not reaching to the acetabulum), S i t e o f i n f e c t i o n : intestine. an oval seminal vesicle and smaller eggs (Ching 1974, T y p e l o c a l i t y : Balneario Orense (38°42’S; 59°47’W), Xiao-Lin 1976). M. majestova can be distinguished by Buenos Aires province, Argentina, January 1997. having longer intestinal caeca, a complete ring of S p e c i m e n s d e p o s i t e d : holotype (No. 3955) and vitelline follicles and eggs with a thicker shell. From M. paratypes (No. 3956) in the Helminth Collection, Museo de feliui, the new species differs in having shorter intestinal La Plata, La Plata, Buenos Aires province, Argentina; caeca (not reaching to the posterior border of the paratype in the helminthological collection of the Institute acetabulum), larger prostatic cells and vitelline folicles of Parasitology, České Budějovice, Czech Republic, not forming a complete ring. (IPCAS D-405). Comparison with the species from South America E t y m o l o g y : the specific name is derivated from the name shows that the new species differs from M. nicolli of the type locality Orense. Travassos, 1920 in having a larger oral sucker and ovary

231 and in the absence of a voluminous complex genital incomplete ring and smaller eggs (Etchegoin and atrium-metraterm. It differs from M. pulcherrima Martorelli 1997). Travassos, 1929 in having a sucker ratio close to 1 : 1, a The new species described here, together with smaller oral sucker and a different form and Levinseniella anenteron (Szidat, 1964), are the only two configuration of vitellarium (Deblock 1972). The new microphallids reported from Larus dominicanus in species can be distinguished from M. bravoae Caballero South America. et Ibañez, 1970 by the shorter intestinal caeca and different form and extension of the vitelline follicles Acknowledgments. The authors gratefully thank Ulyses F. J. (Caballero and Ibañez 1970). M. orensensis differs from Pardiñas (UNLP) for his valuable collaboration in the field M. bonaerensis Etchegoin et Martorelli, 1997 in having work and Robin M. Overstreet, (Gulf Coast Research shorter intestinal caeca (not reaching to the testicular Laboratory, Ocean Springs, U.S.A), for providing literature fields), a trilobed ovary, vitellarium forming an not available in Argentina.

REFERENCES

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Received 26 March 1997 Accepted 17 October 1997

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