Polymorphidae

Abstract: The family Polymorphidae is briefly discussed, and a key to its genera is presented. The subfamilies Polymorphinae Meyer, 1931, and Corynosomatinae Petrochenko, 1956, are suppressed. Southwellina Witenberg, 1932, is considered valid and is redefined. It contains S. hispida (Van Cleave, 1925), S. macracanthus (Ward et Winter, 1952) comb. n., and S. dimorpha sp. n. The new species was found as juveniles in crayfish, Procambarus clarkii, in Louisiana, and as adults in white ibis, Eudocimus albus, in Florida. It differs from other species in its sexual dimorphism, the female having large hooks and 1 field of trunk spines, and the male having smaller hooks and 2 fields of trunk spines. The following species are considered synonyms of S. hispida: Arhythmorhynchus duocinctus Chandler, 1935; A. fuscus Harada, 1939; Polymorphus ardeae Belopolskaia, 1958; and Hemiechinosoma ponticum Petrochenko et Smogorjevskaia, 1962. Skrjabinorhynchus Petrochenko, 1956, is suppressed and its species are recombined as Arhythmorhynchus capellae (Yamaguti, 1935) comb. n., and Arhythmorhynchus eroliae (Yamaguti, 1939) comb. n. The resulting homonym, A. capellae Schmidt, 1963, is renamed Arhythmorhynchus jeffreyi nom. n. The family Polymorphidae Meyer, 1931, is a homogeneous assemblage of species, most of which are parasites of aquatic birds and mammals. Distinction between species is usually difficult, and between genera even more so. When first proposed, most genera were based on one or a few species. Each genus had some distinctive characteristics which readily separated it from other genera. But as more species were discovered, differences between genera became less apparent; today very slight distinctions are used to separate them. For example, Corynosoma differs from Polymorphus only in possessing genital spines, and in some species the spines are on only one sex. Efforts by Petrochenko (1956) and Yamaguti (1963) to divide the family into the subfamilies Polymorphinae Meyer, 1931, and Corynosomatinae Petrochenko, 1956, resulted in placing genera as obviously closely related as Polymorphus and Corynosoma in different subfamilies. As this is less than useful, I cannot accept these subfamilies as valid. The discovery of a new species in this family has stimulated me to review the status of these related genera. It could be logically argued that all species in this family belong to a single genus. On the basis of similarity of form, embryology, and biology they are obviously genetically similar. However, for a Received for publication 13 October 1972. classification to be workable it must help distinguish between species groups in the most convenient manner possible. Therefore, I have taken a more liberal approach and recognize nin genera, which can be diagnosed by the following key. Key to genera in Polymorphidae Meyer, 1931 (Syn. Filicollidae Petrochenko, 1956) la. Cement glands kidney-shaped. Proboscis of adult female greatly swollen, with hooks restricted to short, radially arranged rows on anterior surface. Parasites of water birds Filicollis Liihe, 1911 lb. Cement glands claviform or tubular. Proboscis swollen or not; when swollen, longitudinal rows of hooks cover entire proboscis 2 2a. Genital spines present on at least one sex. Parasites of aquatic birds and mammals --.---... ---Corynosoma Liihe, 1904 (Syn. Chentrosoma Monticelli, 1905, nec Porta, 1906; Echinosoma Porta, 1907, partim.) 2b. Gental spines absent on both sexes ----3 3a. Anterior end of trunk greatly swollen, separated from rest of trunk by conspicuous constriction 4 3b. Anterior trunk not separated from posterior portion by narrow constriction 5 4a. Anterior trunk with 1 field of spines surrounding it. Parasites of Cetacea .....--Bolbosoma Porta, 1908 (Syn. Echinorhynchus Zoega in Miiller, 1776, partim; Bolborhynchus Porta, 1906.)

Abstract: Over 700 specimens of Corynosoma strumosum (Rudolphi, 1802) Luhe, 1904 were collected from one young male Caspian seal, Pusa caspica (Gmelin) in the southern land-locked Caspian Sea in April, 2009. Collected worms showed consistent variations from those reported by other observers using light microscopy especially in proboscis hook and trunk spine patterns. SEM images revealed many features that have not been previously reported including the shape and distribution of trunk spines, dorsoventral differences in proboscis hooks and their organization, the baldness of anterior proboscis, the rough egg topography, epidermal micropores, and variations in the female gonopore. This isolated population of C. strumosum from the land-locked Caspian Sea is distinguished from others reported from open waters elsewhere by the distribution of trunk spines, consistently smaller size of trunk and testes, larger eggs, and fewer proboscis hooks. Histopathological sections reveal the invasive path of worms in host tissue with damage to intestinal villi and worm encapsulation. Information obtained from SEM studies and histopathological sections is reported for the first time.

Abstract: Polymorphid acanthocephalans with long necks, spheroid proboscides, and eggs without polar swellings of the fertilization membrane constitute a morphologically distinct group of species. In the past, this taxon was considered a separate genus, Profilicollis. More recently, workers have been unwilling to accept these features as generic-level characters, and presently the group is considered a subgenus of Polymorphus. An analysis prompted by our studies of various polymorphid cystacanths in crabs along the coasts of Scotland and the U.S.A. reveals that all records of Polymorphus in decapods refer to species with 6 cement glands frequently assigned to Hexaglandula, to incidental occurrences of species purported to be Polymorphus minutus, or to species of the subgenus Profilicollis. Occurrence in decapod crustaceans implies substantial life history differences from the other species of the genus occurring in amphipod crustaceans. We conclude this, together with morphological distinctiveness, justifies return of Profilicollis to full generic status within Polymorphidae.

Abstract: The genus Southwellina is composed of 3 described species, i.e., S. hispida (the type species), S. dimorpha, and S. macracanthus. All 3 are endoparasites of fish-eating birds that have worldwide distributions. Morphologically, the genus is characterized by possessing a short and compact trunk, 2 fields of spines in the anterior region of the trunk (in at least 1 sex), a short cylindrical proboscis (sometimes with a swollen region armed with numerous longitudinal rows of hooks), a double-walled proboscis receptacle, and 4 tubular cement glands in males. In the current study, specimens identified as S. dimorpha were collected from Eudocimus albus (white ibis), the type host from the Gulf of Mexico. Sequences of 2 nuclear genes (small subunit [SSU] and long subunit [LSU] ribosomal DNA) and 1 mitochondrial gene (cytochrome c oxidase subunit 1 [cox 1]) of S. dimorpha and S. hispida were obtained and used to reconstruct the phylogenetic relationships of both species with respect to published sequences ...