Dinemoura discrepans Cressey, 1967 (Copepoda, Siphonostomatoida, Pandaridae) is redescribed based on the specimens taken from four species of sharks caught off the southeast coast of Taiwan. The four species of sharks are: pelagic thresher, Alopias pelagicus Nakamura; bigeye thresher, A. superciliosus Lowe; blacktip shark, Carcharhinus limbatus (Müller et Henle); and oceanic whitetip shark, C. longimanus (Poey). Although our redescription shows certain differences from the original description, after re-examination of the museum specimens studied by R. F. Cressey in making the original description, it was confirmed that the specimens from off Taiwan are identifiable with D. discrepans. Carcharhinus limbatus is currently known to host 19 species of parasitic copepods, of which D. discrepans is the first one of this copepod genus.
Dracunculus globocephalus Mackin, 1927 (Nematoda: Dracunculoidea) is redescribed from specimens collected from the mesentery of the snapping turtle, Chelydra serpentina (L.), in Louisiana, USA. The use of scanning electron microscopy, applied for the first time in this species, made it possible to study details in the structure of the cephalic end and the arrangement of male caudal papillae that are difficult to observe under the light microscope. This species markedly differs from all other species of Dracunculus in having the spicules greatly unequal in size and shape, in the absence of a gubernaculum, and in the disposition of male caudal papillae. The validity of D. globocephalus is confirmed, but the above mentioned morphological differences are not sufficient for listing it in a separate genus. This is the first record of D. globocephalus in Louisiana.
Eimeria dorcadis Mantovani, 1966 is redescribed from dorcas gazelle (Gazella dorcas (L.)) from Saudi Arabia. Oocysts were detected in 7 out of 22 faecal samples (32%) using floatation method. The sporulated oocysts are cylindrical, slightly flattened at the micropylar pole, measure in average 32 × 19 μm (27-36 × 16-24 μm), length/width ratio being 1.7 (1.5-2.1). Oocyst wall is 1.2 μm thick, smooth, double-layered; outer layer is slightly thicker, light blue in colour; inner layer brownish, with micropyle in the inner layer and apparently continual outer one, measures 2.2 μm, but lacks a micropylar cap. The sporocyst elongate-ellipsoidal, measures 14 × 8 μm (12-17 × 6-9 μm), length/width ratio being 1.8, with sporocyst residuum as circular compact, coarse, refractile granules. Stieda body is present, while substieda body is absent. Sporozoites banana-shaped, measure 11 × 2.5 μm, each with a large spheroidal refractile body at the wider pole. Sporulation time is 2-3 days at 25 ± 2 °C.
Two fish cestodes, the little-known Eubothrium fragile (Rudolphi, 1802) and E. rugosum (Batsch, 1786), the type species of the genus Eubothrium Nybelin, 1922, are redescribed on the basis of new material from twaite shad, Alosa fallax (Lacépède, 1803), from England and burbot, Lota lota (Linnaeus, 1758), from Russia, respectively. The tapeworms are compared with two other species of the genus, E. crassum (Bloch, 1779) and E. salvelini (Schrank, 1790), common parasites of salmonid fish in the Holarctic. The most notable differential characters are the size and the shape of the scolex (smaller and oval in E. fragile), the shape of the apical disc (four or more indentations in E. crassum), the number and size of the testes (the largest and least numerous in E. rugosum), and the position and size of the vitelline follicles (almost entirely cortical in distribution in E. fragile and E. crassum versus largely medullary in E. rugosum and E. salvelini). A comparison of species has also shown the morphological similarity of the freshwater species (E. rugosum and E. salvelini) on one hand and those of marine origin, E. fragile and E. crassum, on the other, with the latter species occurring also in fresh waters. A key to the identification of the species studied is also provided.
Eucoleus schvalovoj Kontrimavichus, 1963 (Nematoda: Capillariidae) is redescribed. The original description of this species was brief and inadequate in thal it was based on just a few specimens removed from the Eurasian otter, Lutra lutra (Linnaeus, 1758) in the Khabarovsk region, USSR. Detailed morphological study of several specimens of E. schvalovoj from the oesophagus of L. lutra from Spain revealed new characters, above all in males, and allows for a better characterisation of this species. Since its original description £. schvalovoj has only been recorded in Spain.
Nonparasitic lamprey found in the Beli Drim River basin (Drin River drainage, Adriatic Sea watershed) represents a valid species Eudontomyzon stankokaramani Karaman, 1974. From other species of the genus Eudontomyzon it differs in its dentition, and the number and form of velar tentacles. This is the first Eudontomyzon species found in the Adriatic Sea watershed.
The type species of the monotypic genus Gessyella Freitas, 1959, G. latridopsis (Johnston et Mawson, 1945) (Nematoda: Capillariidae), is redescribed from specimens found in the rectum of the marine fish Nemadactylus bergi Norman (Latridae, Perciformes) (a new host record) from the southwestern Atlantic Ocean off Mar del Plata, Argentina. In addition to the morphological and biometrical variability of this species, some new, previously unreported taxonomic features, such as the extent of the spination of the spicular sheath, the morphology of the spicular canal, the distal end of the spicule, the ejaculatory duct, the cloaca, the seminal vesicle, vas deferens and the testis, are described for the first time. Despite the long geographical distance of G. latridopsis records (Australia vs. Argentina), the morphology of the newly collected specimens is in agreement with the existing descriptions of G. latridopsis and both host species are closely related. Therefore, the Argentine specimens are considered to belong to this species.
Specimens of the elasmobranch, Isurus oxyrinchus Rafinesque, captured in 1999 in the state of Santa Catarina, Brazil, were parasitized with the poecilacanthoid trypanorhynch cestode Gymnorhynchus isuri Robinson, 1959, that is redescribed here. New details of scolex and proglottid morphology are given. These details are mainly related to tentacle armature, terminal genitalia and observations of external morphology of proglottids.
Ichthyofilaria argentinensis Incorvaia, 1999 (Nematoda: Philometridae) is redescribed from type specimens and from parasites collected from the swim bladder of Argentine hakes Merluccius hubbsi Marini, 1933 caught at the Gulf of San Jorge (46°30'S, 66°30'W), Argentine Sea, in July, 1998. Sixteen out of 80 hakes (20%) were found to be parasitised by gravid females of this philometrid. After revision of both these nematodes and type material, the following differences from the original description of the species were observed: (a) cuticle with fine transverse striations, instead of smooth cuticle; (b) presence of cephalic papillae and a pair of amphids; (c) absence of swellings in the oesophagus; (d) oesophageal gland appendix very large and lobulate rather than small and vermiform, and (d) presence of vulva and vagina. The morphological features given in the redescription allow the confirmation of the identity of I. argentinensis as a valid species and to distinguish it from other members of the genus.
The generic diagnosis of Mehdiella Seurat, 1918 is emended based on study and redescription of Mehdiella microstoma (Drasche, 1884) from the caecum of Testudo graeca Linnaeus, 1758 collected in Settat, Morocco and on study and description of a new species, Mehdiella petterae sp. n., from the large intestine of Testudo hermanni (Gmelin, 1789) collected in Catalonia, Spain. Scanning electron microscopy (SEM) studies revealed substantial differences in the structure of the mouth and the caudal end, and made possible to differentiate the new species from the others. SEM studies showed the real and sound characteristics of the genus Mehdiella, namely number of anal papillae 2 instead of 3, post-anal papillae pedunculate or sessile instead sessile.