Two new species of Scalithrium (Cestoda: Rhinebothriidea) from rajiform batoids of the Argentine Sea

Two new species of Scalithrium Ball, Neifar & Euzet, 2003 were found in rajiform batoids of the Argentine Sea: Scalithrium kirchneri sp. nov., parasite of the Rio skate Rioraja agassizii (Müller & Henle) from waters off Buenos Aires Province, and Scalithrium ivanovae sp. nov., parasite of the La Plata skate Atlantoraja platana (Günther) from waters off Río Negro Province. Scalithrium kirchneri sp. nov. and S. ivanovae sp. nov. differ from their congeners by having a particular combination of features including: total length, number of loculi on the distal bothridial surface, absence of bilobed bothridia and number of testes. Additionally, S. kirchneri sp. nov. can be distinguished from S. ivanovae sp. nov. by the presence of a vaginal sphincter and seminal receptacle, by the position of the entrance of the vas deferens into the cirrus sac, and by the microthrix pattern on the proximal bothridial surface. Based on this and previous studies, we conclude that some morphological traits may not be considered as key characters for the generic diagnosis of Scalithrium due to their variability within the genus. These characters include the musculature disposition in bothridial transverse septa and position of the entrance of the vas deferens into the cirrus sac, which certainly complement other diagnostic characters at a specific level. The discovery of these two species represents the first record of the genus Scalithrium in temperate waters of the Southern Hemisphere. In addition, this study is the first to undoubtedly identify batoids from the order Rajiformes as hosts for Scalithrium.

New species of Temnocephala (Platyhelminthes, Temnocephalida) ectosymbiont on vulnerable species of aeglids (Crustacea, Anomura) from the Neotropical Region

A new species of the genus Temnocephala Blanchard, 1849 from southern Brazil was found on two species of anomuran crustaceans, Aegla spinipalma Bond-Buckup & Buckup, 1994 and Aegla grisella Bond-Buckup & Buckup, 1994, the latter classified as a vulnerable species by the "Lista de Referência da Fauna Ameaçada de Extinção no Rio Grande do Sul. Decreto no 41.672, de 11 junho de 2002". The crustaceans were collected from a tributary creek of the Forqueta river, Perau de Janeiro, Arvorezinha and a tributary creek of the Fão river, Pouso Novo, Rio Grande do Sul, Brazil; both localities belong to the Sub-Basin of Forqueta River. The new species differs from seven other temnocephalans epibionts on Aegla Leach, 1820, by having the following characters: 1. a long and slightly curved cirrus, 2. two vaginal sphincters, one proximal, big and asymmetric, and one distal, smaller and symmetric, and; 3. longer than wide, elongated epidermal 'excretory' syncytial plates (EPs), with a almost horizontally central excretory pore, displaced to the anterior portion of the plate. The new species' EP is the largest in total length among epibionts temnocephalans in crustaceans already registered. Regarding the similarities with the male reproductive system of Temnocephala axenosMonticelli, 1898, the new species has important differences in the female reproductive system. It has a larger proximal vaginal sphincter, located in the middle of the vagina, while the smaller distal one is at the extreme end of the organ. Besides that, the vaginal portion between the proximal and distal sphincters is conspicuous, with a strong muscular wall. This is the first record of a species of Temnocephala in the Taquari Valley, as well in the 'Perau de Janeiro', which is an area with a rich endemic fauna.

Structure, innervation, mechanical properties and reflex activation of a striated sphincter in the vestibule of the cat vagina

Vaginal constriction might be important for reproduction in mammals, but existing information is both limited and controversial. This paper shows the structure, mechanical properties, innervation and reflex response of a striated sphincter in the vestibule of the cat vagina. A Foley catheter coupled to a pressure transducer detected in the lumen of the vestibule a pressure wave that was induced by stimulation of the external branch of the motor pudendal nerve. The peak pressure of the wave induced by bilateral stimulation (30.6 cm H2O) was about double of the peak pressure wave induced unilaterally. The tetanus/twitch amplitude ratio was 4.5. The sphincter that produces the increase in vaginal pressure fatigues slowly. Digital, point-to-point summation of unilateral waves was greater than the wave induced bilaterally. Summation of the pressure wave induced by the separate stimulation of the terminal motor branches was also greater than the wave induced by the entire motor nerve. This might reflect multiple innervation of muscle fibres. Single, controlled probing of the vaginal vestibule induced a reflex discharge in the motor nerve. Repetitive probing (10 Hz) induced a motor nerve post-discharge lasting >1 min. The vaginal sphincter is two-half rings of striated muscle fibres in the wall of the vaginal vestibule; the fibres end freely in the dorsal and ventral midlines. Penetration of the vestibule by the penis might trigger sustained contraction of the vaginal sphincter.

Echinocotyle capensis n.sp. (Cestoda: Hymenolepididae) from South African waterfowl

Echinocotyle capensis n.sp. is described from Cape shovelers (Anas smithii (Hartert)) and Cape teal (Anas capensis Gmelin) collected at Barberspan, Transvaal Province, Republic of South Africa. Echinocotyle capensis is a small cestode up to 1.62 mm long with 10 rostellar hooks 50–55 μm long. It most closely resembles Echinocotyle singhi Srivastava and Pandey, 1980 but has slightly longer rostellar hooks and a shorter cirrus sac, and lacks the vaginal sphincter present in E. singhi.

Morphology and description of Helicotylenchus crassatus n. sp. (Nematoda: Hoplolaimidae) from eastern Canada

A new plant parasitic species of the genus Helicotylenchus Steiner, 1945, common to eastern Canada, is described and illustrated. Helicotylenchus crassatus can be distinguished from closely related species by the sclerotization of the head skeleton, size and position of the anterior cephalid, and thickness of the vagina. The morphology and diagnostic value of the head skeleton, hypodermal commissures, vulva, vagina, vaginal sphincter, and oviduct are discussed.

A morphological study of a fish tapeworm, Proteocephalus pollanicola

An account is given of the general structure of Proteocephalus pollanicola. The genital system is dealt with in greater detail. The characteristic features of the species are enumerated.The male portion of the reproductive system consists of 60–75 testes in a single layer; vasa efferentia with a lining epithelium; a wide, coiled vas deferens; a small cirrus-sac; a coiled ejaculatory duct and a short cirrus. A description is given of the histological structure of the male ducts.The vagina opens anterior to the cirrus-sac. A well-developed vaginal sphincter is present. The seminal canal communicates with the oviduct and the uterine canal. An oocapt is present; the transverse vitelline ducts and the ovary open into it. A few unicellular glands are present hi the vicinity of the oocapt; these possibly represent Mehlis's gland. An ootype is absent. The histological structure of the female ducts is described.