Reassignment of Lamanema from Nematodirinae to Molineinae (Nematoda: Trichostronglyloidea).

The monospecific Lamanema historically has been assigned to the Nematodirinae within the Molineidae. Inconsistencies in morphological characters, within a phylogenetic context for Nematodirinae, led to a re-evaluation of the putative relationships and taxonomic placement of Lamanema. Among 7 putative synapomorphies for Nematodirinae, Lamanema possesses only 1, large eggs. Large eggs, sporadically present in phylogenetically disparate taxa of trichostrongyles, are equivocal with respect to placement of Lamanema; it is considered that possession of this single homoplasious character alone is insufficient justification to retain the genus in Nematodirinae. Affinities with the Trichostrongylidae (Cooperiinae or Haemonchinae) have also been proposed; however, Lamanema possess neither of 2 synapomorphies that diagnose monophyly of the family. Lamanema is retained in the Molineidae and transferred to the Molineinae as it possesses all characters of the family as currently defined. The origin of Lamanema represents a secondary colonization of ruminants by molineids and provides no context for elucidating the history of the Nematodirinae and Nematodirus.

Preliminary comments on a phylogenetic study of the order Diphyllidea van Beneden in Carus, 1863.

The basis for a preliminary analysis of the relationships within the monophyletic Diphyllidea is outlined. Information on morphological characters and their interpretation within a phylogenetic context are presented. A cladistic analysis at the species level was conducted based on a matrix of 21 morphological characters. Character polarity was determined by taxonomic outgroup analysis relative to the basal orders, Pseudophyllidea and Haplobothriidea. The phylogeny for the diphyllideans was found to be poorly resolved based on characters currently available for evaluation. Computer assisted cladistic analysis found three equally parsimonious trees with a consistency index of 0.54. The topology of these trees shows that Ditrachybothridium macrocephalum is the basal taxon and the putative sister group for species of Echinobothrium; Macrobothridium rhynchobati is grouped among species of Echinobothrium. If the classification is to be consistent with this tree, M. rhynchobati should be included in the genus Echinobothrium. This observation should be carefully examined, considering the relative paucity of useful morphological characters currently available for this group.

Echinocephalus janzeni n. sp. (Nematoda: Gnathostomatidae) in Himantura pacifica (Chondrichthyes: Myliobatiformes) from the Pacific coast of Costa Rica and Mexico, with historical biogeographic analysis of the genus.

Echinocephalus janzeni n. sp. in the stingray, Himantura pacifica, is described from the eastern Pacific Ocean off the coasts of Costa Rica and southern Mexico. On the basis of the presence of 6 postanal caudal papillae, and modified annules anterior to the caudal alae in males, E. janzeni is most similar to Echinocephalus daileyi and Echinocephalus diazi. Specimens of E. janzeni are distinguished from those of E. daileyi by bilobed caudal alae and long cervical sacs that extend up to 65% of the length of the esophagus; E. janzeni is differentiated from E. diazi by the number of rows of cephalic spines (30-38 vs. 26-27), arrangement of the postanal caudal papillae, 3 rather than 2 preanal papillae, relative position and distance between the anus and vulva (395-460 microm vs. 70 microm), the digitiform female tail with a terminal cuticular fold, and the length of the female tail (450-480 microm vs. 270 microm). Cladistic analysis of the 10 Echinocephalus spp. resulted in a single most parsimonious tree (consistency index=0.893) and placed E. janzeni in a highly derived subclade where E. daileyi is the sister species of E. diazi + E. janzeni. Historical biogeographic analysis of hosts and parasites provides support for origins in the Pacific rather than the Atlantic for the potamotrygonid stingrays.

The synlophe and other structural characteristics of Sarwaria bubalis (Nematoda: Trichostrongyloidea) from cattle in Guyana.

The synlophe (longitudinal, surface cuticular ridges) of Sarwaria bubalis is described for the first time. It is a tapering lateral synlophe of about 40 ridges. The synlophe of S. bubalis is similar to that of Ostertagia ostertagi but markedly different from that of species of Spiculopteragia and Mazamastrongylus. New information is provided also on the structure of the esophagus and perivulval pores. The esophageal valve is more than twice as long as wide. The bilateral perivulval pores were located 192-267 microns posterior to the vulva and dorsal to the lateral lines. The new information will be useful in a study of the generic level systematics of the Ostertaginae. Sarwaria bubalis appears to be well established in tropical South America where it infects its normal host, the Asian water buffalo Bubalus bubalis, as well as domestic cattle Bos taurus and mixed breed cattle B. taurus x Bos indicus.

Eulimdana rauschorum n. sp., a filarioid nematode (Lemdaninae) from Larus dominicanus in Antarctica, with comments on evolution and biogeography.

Eulimdana rauschorum n. sp. is described from southern black-backed gulls, Larus dominicanus Lichtenstein in Antarctica. The species is most similar to Eulimdana lari (Yamaguti, 1935) from Charadriiformes in the Holarctic. Males have spicules equal in length that are asymmetric in structure distally. There are 4-5 and 3-5 caudal papillae in rows to the right and left of the anus, and 2 small genital papillae at the posterolateral margin of the anus. Females have a variable number of prominent caudal papillae and large microfilariae (365 micron in length). The morphological similarities and host distribution of E. rauschorum and E. lari suggest they are sister taxa in which cladogenesis of the former accompanied the isolation and subsequent speciation of Larus dominicanus in the Southern Hemisphere.