The systematic position of Lauroiinae Skrjabin and Schikhobalova, 1951 (Nemata: Heterakoidea: Aspidoderidae), as revealed by the analysis of traits used in its diagnosis.

During our work on biodiversity of parasites of mammals of the Neotropics we collected numerous nematodes assignable to species of the family Aspidoderidae (Nemata: Heterakoidea). These nematodes occur as parasites of the cecum and large intestine of marsupials, rodents and xenarthrans (armadillos) only in the New World. As aspidoderid nematodes have been little studied beyond their alpha taxonomy, it is the purpose of the present paper to apply phylogenetic systematic methods to more completely understand the evolutionary relationships of the included species. Members of the aspidoderid subfamily Lauroiinae have had very little work applied to their systematic relationships and no systematic revisions exist that include all recognized species. Diagnostic characters that define species in this subfamily include plate-like cuticular structures on the anterior end. Herein we define a suite of 52 characters derived from studies of specimens using both light and electron microscopy. Our phylogenetic systematic analysis included the eight known species in the Lauroiinae, seven of the Aspidoderinae and four outgroup taxa. The results indicate that the Lauroiinae is paraphyletic, that the cephalic plates on the anterior end are not synapomorphies for the Lauroiinae, and that structures forming the cordon are present in all species of the family. We propose elimination of the subfamily designations in the family Aspidoderidae and we show the utility of using additional characters in the diagnosis of the family and the genera within this family. The resulting hypothesis should serve as the foundation to understand the historical associations of the nematodes with the mammals they infect. © The Willi Hennig Society 2008.

Aspidoderidae from North America, with the description of a new species of Aspidodera (Nematoda: Heterakoidea).

Aspidodera sogandaresi n. sp. (Heterakoidea: Aspidoderidae) from Dasypus novemcinctus Linnaeus, 1758 is herein described. This nematode occurs in armadillos from as far south as the canal zone of Panama, north through central Mexico, and into the southern United States. Previously identified as Aspidodera fasciata (Schneider, 1866), this new species has blunt projections on the lips and lateral expansions at the distal tips of the spicules, whereas A. fasciata has conspicuous digitiform projections on the lips, and a terminal round expansion at the tips of the spicules. Other species of the family present in North America include Aspidodera binansata Railliet and Henry, 1913; Aspidodera vazi Proença, 1937; and Lauroia trinidadensis Cameron, 1939.

A new species of Pelecitus (Filarioidea: Onchocercidae) from the endangered Tehuantepec jackrabbit Lepus flavigularis.

Pelecitus meridionaleporinus n. sp. from the Tehuantepec jackrabbit is described. The new species differs from Pelecitus helicinus (Molin, 1860) in having delicate transverse striations, a salient vulva, and a readily apparent preesophageal ring; P. helicinus has teardrop cells around the vulva, which are lacking in the species presently described. The new species is different from Pelecitus scapiceps (Leidy, 1886) in having the vulva anterior to the esophageal-intestinal junction and wider lateral alae. Pelecitus scapiceps is found in the tarsal bursa of the hind feet of lagomorphs, whereas P. helicinus is found around tendons of legs and feet of birds. Pelecitus meridionaleporinus n. sp. occurs in the subcutaneous tissue at the base of both ears. This is the second species in Pelecitus Railliet and Henry, 1910 that occurs in New World lagomorphs, and the third found infecting mammals.

Aspidoderid nematodes from bolivian armadillos, with the description of a new species of Lauroia (Heterakoidea: Aspidoderidae).

One nine-banded armadillo (Dasypus novemcinctus) and 1 yellow armadillo (Euphractus sexcinctus) were necropsied in the field during an expedition to collect parasites of mammals in Bolivia. A total of 205 Aspidodera binansata Railliet and Henry, 1913 (Heterakoidea: Aspidoderidae), and 40 specimens of Lauroia bolivari n. sp. (Heterakoidea: Aspidoderidae) were recovered from the cecum and large intestines of D. novemcinctus and E. sexcinctus. Aspidodera esperanzae Fujita et al., 1995, is proposed as a junior synonym of A. binansata based on the structure of the cordons on the hood. Lauroia bolivari n. sp. has an undercut cephalic cap and unequal spicules. It differs from other species in the genus in the shape of the cephalic cap and from Lauroia travassosi Proença, 1938, in the relative proportion of the spicules. This is the first record of a member of Lauroia Proença, 1938, for Bolivia.

The nematode fauna of long-nosed mice Oxymycterus spp. from the Bolivian Yungas.

During a long-term survey of the parasites of mammals from all over Bolivia, 44 individuals of Oxymycterus inca and 6 of Oxymycterus paramensis were collected and examined for parasites from the foothills and Eastern Cordillera (Los Yungas) of the Andes of Bolivia. Three species of nematode were found including, from the cecum, a previously unknown genus and species of pinworm, Caroloxyuris boliviensis n. gen, n. sp., aspidoderids representing Nematomystes rodentophilus, and from the stomach, Protospirura numidica criceticola. These helminths occurred in prevalences of 25, 9, and 14%, respectively, in O. paramensis. Caroloxyuris boliviensis resembles species included in the genus Syphacia in the structure of the cephalic mask and copulatory organs, and the extension of lateral alae. However, males of this species possess only 2 mamelons on the ventral surface of the body. Caroloxyuris can be recognized as being distinct from both Helminthoxys and Rauschtineria in the ornamentation of the mamelons and the shape of cephalic mask. A redescription of N. rodentophilus is provided, and Nematomystes scapteromi is transferred from Ansiruptodera to Nematomystes.

A new species of Spauligodon (Nematoda: Pharyngodonidae) parasite of Cnemidophorus spp. (Lacertilia: Teiidae) from southern Mexico.

A new species of Spauligodon collected from Cnemidophorus mexicanus and C. deppii is described in this study. The species is placed in Spauligodon because the caudal alae start at the level of the precloacal papillae and embed the adcloacal papillae. The new species is most similar to S. goldbergi, but diagnostic traits of the former are the presence of 2 ridges in lateral alae, flaplike expansions in the caudal end of lateral alae, and a smooth tail for males. This species is the eighth recorded in the neotropics.

Helminth infracommunity structure of the sympatric garter snakes Thamnophis eques and Thamnophis melanogaster from the Mesa Central of Mexico.

Seventy-two Mexican garter snakes (Thamnophis eques) and 126 black-bellied garter snakes (T. melanogaster) were collected from 4 localities of the Mesa Central of Mexico between July 1996 and February 1998 and examined for helminths. Both species of garter snakes occurred sympatrically in every locality except in Lake Cuitzeo. Both species of snakes shared 9 helminth species, and in general, T. melanogaster hosted a larger number of species than T. eques. In each locality, a different helminth species showed the highest levels of prevalence and abundance (Spiroxys susanae in Ciénaga de Lerma, Telorchis corti in Lago de Pátzcuaro, Proteocephalus variabilis in Lago de Cuitzeo, and Contracaecum sp. in Lago de Chapala). Helminth communities in garter snakes of the Mesa Central are depauperate and dominated by a single parasite species. In those localities where the snakes occurred in sympatry, helminth communities were, in general, more diverse and species-rich in T. melanogaster. Differences in the ecology and physiology of these species of garter snakes may explain this pattern because black-bellied garter snakes (T. melanogaster) are more aquatic than Mexican garter snakes (T. eques) and primarily eat aquatic prey, potentially exposing themselves to a larger number of helminths transmitted by predator-prey infection. The helminth infracommunities of garter snakes in the Mesa Central of Mexico show a strong Nearctic influence because most of the species infecting these hosts have been recorded in other Nearctic colubrid snakes. However, the helminth infracommunities of these garter snakes are less species-rich and less diverse than those in colubrid snakes in more temperate latitudes. The widespread ecological perturbation of sampling sites in the Mesa Central because of human activity, and geographic differences in foraging ecology of the hosts and, thus, exposure to parasites transmitted by intermediate hosts may help to explain these patterns.