The family Rhytidodidae corresponds to a group of digenetic trematodes described in sea turtles, which currently includes only two genera:
Thus, the purpose of this note is to describe the first occurrence of specimens of
In March 2019, a female olive-ridley (observed during necropsy with visualization of the ovaries) considered to be an adult (with a curvilinear carapace length of 67.3 cm) was found dead on Mosqueiro beach in the municipality of Aracaju (11°01′57″S, 37°05′00″W) in the State of Sergipe, Brazil. Necropsy was performed immediately and four specimens of
The collected trematodes were preserved in ethanol 70 %, stained with carmine, and cleared with eugenol. Morphometric data was collected with the aid of a Global optics light microscope using the S-EYE software program. Measurements are reported in micrometers, except when indicated, with the mean followed by the range in parenthesis. The helminths were deposited in the Helminthological Collection of the Instituto Oswaldo Cruz in the state of Rio de Janeiro (number requested), Brazil.
The identification used in this report followed the genus taxonomic key proposal by Blair (2005), the original description by Looss (1901), comments by Blair and Limpus (1982) and redescription by Caballero and Caballero (1954). The morphometric comparison (Table 1) was made using the works of Caballero and Caballero (1954), Bilqees (1974), Blair and Limpus (1982) and Cavaco
Morphometric data of
Caballero y Caballero, 1954 | Bilqees, 1974 | Blair and Limpus, 1982 | Cavaco et al., 2021 | Present report | |
---|---|---|---|---|---|
Locality | Panamá | Pakistan | Australia | Brazil | Brazil |
N | 4 | 1 | 12 | 2 | 4 |
Host | |||||
Body length (mm) | 13.911 – 14.243 | 16.9 | 5.85 – 17.130 (6.800) | 4.94 – 5.68 (5.31) | 5.8 – 7.6 (6.48) |
Body width (mm) | 1.378 – 1.610 | 1.1 | 1.190 – 1.610 (1.350) | 1.2 – 1.34 (1.27) | 0.77 – 1.15 (0.97) |
Oral sucker length | 133 | 600 | 350 – 460 (460) | 318 – 392 (355) | 280 – 441 (371) |
Oral sucker width | 515 – 664 | diameter | 500 – 740 (740) | 403 – 535 (469) | 400 – 499 (444) |
Pharynx length | 160 | 180 – 220 (220) | 160 – 200 (180) | 200 – 312 (265) | |
Pharynx width | 110 | 150 – 240 (240) | 147 – 187 (167) | 140 – 253 (189) | |
Oesophagus length | 2324 – 2407 | 2000 | 580 – 2400 (2400) | 676 – 992 (834) | 661 – 885 (723) |
Oesophagus width | 73 – 79 (76) | 36 – 58 (49) | |||
Cirrus sac length | 415 – 465 | (530) | 309 | 160 – 326 (241) | |
Cirrus sac width | 266 – 332 | (420) | 183 | 150 – 242 (193) | |
Ventral sucker length | 365 – 398 | 240 | 230 – 380 (380) | 214 – 255 (234) | 160 – 297 (233) |
ventral sucker width | 349 – 398 | diameter | 300 – 420 (420) | 181 – 193 (187) | 150 – 317 (244) |
Ovary length | 232 – 249 | 130 | 140 – 190 (150) | 169 – 181 (175) | 120 – 296 (206) |
Ovary width | 266 – 274 | 150 | (220) | 204 – 246 (225) | 130 – 256 (177) |
Mehlis gland length | 332 – 415 | – | |||
Mehlis gland width | 498 – 531 | – | |||
Anterior testis length | 664 – 797 | 390 | (740) | 183 – 310 (249) | 300 – 475 (414) |
Anterior testis width | 398 – 465 | 200 | (330) | 168 – 290 (238) | 220 – 396 (296) |
Second testis length | 581 – 780 | 420 | (890) | 338 – 404 (371) | 420 – 509 (463) |
Second testis width | 465 – 481 | 220 | (380) | 244 – 301 (272) | 240 – 406 (298) |
Egg length | 60 – 65 | 55 – 60 | (67) | – | 37 – 63 (51) (n=30) |
Egg width | 34 – 40 | 37 – 45 | (35) | – | 27 – 38 (31) (n=30) |
For this study, formal consent is not required.
Parasite description (Fig. 1, Table 1): elongated parasites with slightly rounded ends, terminal oral sucker showing lateral projections, pharynx present; long oesophagus and pre-acetabular caecal bifurcation, thin cecum running along the body ending near the posterior end of the body; acetabulum in the initial third of the body; rounded pre-testicular ovary; intercaecal uterus between ovary and acetabulum; preacetabular cirrus sac; two slightly oval testicles in tandem; genital pore anterior to the acetabulum; vitelline follicles similar to thin threads that occupy the lateral area of the body, covering the cecum in almost its entirety and occupying the region immediately after the acetabulum to the posterior end of the body.
The specimens analyzed in this note presented the acetabulum in the anterior third of the body, testicles in tandem in the post-equatorial region and the distribution of vitelline follicles that are compatible with the genus
Our specimens differ from
Our specimens also differ from
The size of the egg of the specimens corresponded to those found in
The morphometric analysis of the specimens in the present study demonstrated that the body width, oesophageal width, cirrus sac length and egg length and width are smaller when compared to previously published data, while the pharyngeal values are bigger. These data do not preclude the identification of the specimens and probably reflect only variation within the species.
Observation of the genital pore reveals the opening in a protuberance located directly in front of and slightly to the right of the ventral sucker (Fig. 2). This protuberance had already been observed, initially by Looss (1902) and later by Blair and Limpus (1982).
Later Manfredi
Valente
Gracan
Greiner (2013) reported the presence of
In Brazil, Werneck and Silva (2015) evaluated 136 loggerhead turtles. They found an only specimen of
Pace
Gentile
The last report of
In the present report we present the occurrence of
Reported hosts and localities for Rhytidodes gelatinosus (Rudolphi, 1819) Looss, 1901 (Digenea: Rhytidodidae).
Australia | Blair and Limpus (1982) | |
Brazil | Viana (1924); Travassos |
|
Egypt | Sey (1977) | |
Florida, USA | Luhman (1935); Greiner (2013) | |
Italy | Manfredi |
|
Madeira, Portugal | Valente |
|
Mediterranean Coast, França | Euzet and Combes (1962); Euzet |
|
New Guinea | Braun (1899) | |
Trieste, Adriatic Sea | Stossich (1895, 1898); Braun (1899); Looss (1901) | |
West Mediterranean Sea | Aznar |
|
Brazil | Werneck and Silva (2015) | |
Florida, USA | Greiner (2013) | |
Panama Gulf | Caballero y C. (1954) | |
Mexico | Caballero-Rodriguez (1960) | |
New Guinea | Braun (1899) | |
Pakistan | Bilqees (1974) | |
Rimini, Adriatic Sea | Rudolphi (1819) | |
Cuba | Perez-Vigueras (1955) | |
Florida, USA | Greiner (2013) | |
India | Simha and Chattopadhyaya (1969) | |
Puerto Rico | Fischthal and Acholonu (1976) | |
Florida, USA | Greiner (2013) | |
Brazil | Present report |
Unfortunately, reports of parasitological analysis of olive turtles on the Brazilian coast are scarce, noting up to the present moment only two parasites reported in this host: Werneck