MOLECULAR PHYLOGENETIC ANALYSIS OF GYRINICOLA BATRACHIENSIS (NEMATODA: OXYUROIDEA) LENDS SUPPORT TO THE MONOPHYLY OF THE GENUS AND THE RESURRECTION OF GYRINICOLINAE.

Gyrinicola Yamaguti, 1938, includes 6 species of oxyurid found within the intestinal tract of numerous, larval, anuran species in Europe, Asia, South America, and North America. The systematic placement and hierarchical treatment of the genus has shifted at least 5 times since its discovery; the group was first considered as its own family (Gyrinicolidae), then treated as a subfamily (Gyrinicolinae) of Cosmocercidae, then as a member of the Pharyngodonidae, followed by movement back to the Cosmocercidae, and finally a recent proposal suggested the resurrection of the Gyrinicolidae. Species in the genus vary widely in the morphology of the uterine tract, a characteristic often used to indicate membership in the genus, as it is tied to the reproductive mode. However, until recently very few genetic data were available to aid in the placement of this unique group of worms, and before this study to the best of our knowledge none existed for the North American species. To examine the monophyly and placement of the Gyrinicola we sampled populations of Gyrinicola batrachiensis across North America and screened them for genetic diversity using nuclear markers 18S and 28S. Phylogenies suggest at least 3 clades exist among the nematodes from North America and that these clades, alongside Gyrinicola japonica, form a well-supported group within Oxyuroidea. Further representation of Pharyngodonidae from other vertebrate classes may help clarify the relationship of this historical grouping to other members of the Oxyuroidea.

Pharyngodon mamillatus (Nematoda: Pharyngodonidae) in the ocellated skink Chalcides ocellatus (Squamata: Scincidae) from Egypt: Light and scanning electron microscopic studies.

Twenty-one Pharyngodon mamillatus were recovered from the large intestine of 4 out of 12 ocellated skink Chalcides ocellatus collected from the South Sinai desert, Egypt. The prevalence of infection was 33.33% (intensity 2-4). The recovered pharyngodonid was re-described based on light and scanning electron microscopy. According to the morphology, it was characterized by regular transverse annulations extending from the posterior margin of the lips to the level of the anus, triangular mouth opening was surrounded by three large bilobed lips possessing three papillae, oval-shaped excretory pore, slit-like vulva opening, and slit-like anal ventral opening at the posterior end which terminates with a tail filament. Here, the morphometric measurements of adult female P. mamillatus were given in this study. It has no intraspecific morphological variations from the previously described P. mamillatus, but it appeared with small range on biometric features. These variations may be accounted by host/environment attributes since they exhibit wide host and geographical spectra. The present study was applied for detailed morphological knowledge of the recovered P. mamillatus for strengthening their taxonomic validity. HIGHLIGHTS: The Pharyngodon mamillatus naturally parasite of the intestinal region of Chalcides ocellatus. The present study clarifies the morphological key for the description of P. mamillatus.

A Phylogenetic Assessment of Nematodes (Oxyuroidea: Pharyngodonidae) Infecting Moroccan Lizards.

Molecular tools can be used to estimate the phylogeny of species and to identify cryptic diversity, but their use for parasites has lagged behind that of free-ranging organisms. As an example, in North Africa there is minimal molecular data available for helminth parasites of lizards. In this work we used two molecular markers (the nuclear 18S rRNA and the mitochondrial Cytochrome c Oxidase subunit 1) to investigate the diversity of nematodes of the family Pharyngodonidae parasitizing three genera of lizards from Morocco (Chalcides, Quedenfeldtia and Tarentola) and to explore their co-evolutionary history. Morphological assessments indicated that members of three genera were present: Spauligodon, Thelandros, and Parapharyngodon. Phylogenetic analysis of 18S rRNA sequences indicated the monophyly of the genus Spauligodon, and that some lineages could be distinguished, including Spauligodon auziensis from the host species Tarentola mauritanica, and another unnamed lineage from hosts of the genus Chalcides. However, with this slow-evolving marker some species could not be distinguished. The genus Thelandros was not monophyletic, although relationships were not strongly supported. Analysis of the faster evolving mitochondrial marker clearly separated various species of Spauligodon, as well as distinct unnamed lineages identified in the host genus Chalcides and the host Quedenfeldtia moerens.

Oxyuricassis ekstromi n. sp. (Oxyurida: Pharyngodonidae) from Lasiancistrus saetiger (Siluriform: Loricariidae) from the Eastern Amazon.

Oxyuricassis ekstromi n. sp. is the third species of the genus described from the intestine of Lasiancistrus saetiger Armbruster in Brazil. This species can be easily differentiated from its congeners by the presence of a tooth-like sclerotized piece that occupies half of the stoma and absence of spine projections on the tail of both males and females. Also, males of the new species lack caudal alae present in Oxyuricassis coronatus and Oxyuricassis hexaspinatus. Additionally, we observed a different number and pattern of the distribution of cloacal papilla; males of O. coronatus and O. hexaspinatus have 1 pair of pre-cloacal and 2 pairs of post-cloacal papillae; while the new species has 1 pre-cloacal and 3 post-cloacal pairs of papillae.

Three new species of Pharygodonidae (Nematoda: Oxyuridea) in Laudakia tuberculata (Squamata: Agamidae) from Dehradun, Uttarakhand, India.

Parapharyngodon tuberculata sp. nov., Thelandros tuberculata sp. nov. and Thelandros dehradunensis sp. nov. (Nematoda: Pharyngodonidae) from the large intestine of a rock lizard, Laudakia tuberculata Gray, 1827), are described and illustrated. Parapharyngodon tuberculata sp. nov. is the 8th Oriental species and 59th species assigned to the genus Parapharyngodon and differs from other species of the genus by possessing 3 pairs of caudal papillae, an echinate cloacal lip, 112-115 µm spicule length and postbulbar ovary. Thelandros tuberculata sp. nov. is the 5th and Thelandros dehradunensis sp. nov. the 6th Oriental species, respectively, and they are the 40th and 41st species assigned to the genus Thelandros. They differ from other species of the genus in caudal papillae arrangement, length of spicules, and structure of the anterior end of the esophagus. We transfer Parapharyngodon arequipensis Calisaya and Cordova, 1997 to Thelandros arequipensis (Calisaya and Cordova, 1997) comb. n. based upon the presence of a terminal operculum in the egg and large, pendant, caudal papillae.

New records of helminths of Sceloporus pyrocephalus Cope (Squamata, Phrynosomatidae) from Guerrero and Michoacán, Mexico, with the description of a new species of Thubunaea Seurat, 1914 (Nematoda, Physalopteridae).

A total of 61 specimens of the Red-headed Spiny Lizard Sceloporus pyrocephalus Cope (Phrynosomatidae) collected during the breeding season (June/July 2003, 2004 and 2005) from Western Mexico were examined for helminths. The morphological characterization of the helminths found was made through light microscopy and scanning electron microscopy. Nine taxa of helminths were identified, two cestodes: Mesocestoides sp. and Oochoristica sp., and seven nematodes: Parapharyngodon ayotzinapaensis Garduño-Montes de Oca, Mata-López & León-Règagnon, 2016, Parapharyngodon tikuinii Garduño-Montes de Oca, Mata-López & León-Règagnon, 2016, Parapharyngodon sp., Physalopterinae gen. sp., Skrjabinoptera scelopori Caballero-Rodríguez, 1971, Strongyluris similis Caballero, 1938 and a new species of Thubunaea Seurat, 1914. Larvae of Mesocestoides sp. and Physalopterinae gen. sp. were found in the body cavity and digestive tract, respectively. Excluding the species of Parapharyngodon Chatterji, 1933, S. pyrocephalus is recorded for the first time as a host of the remaining seven taxa of helminths. Additionally, Thubunaealeonregagnonae sp. n. is described and illustrated as a new nematode species, parasite of S. pyrocephalus from Mexico. This new species can be differentiated from the majority of its congeners by the absence of spicules, the particular pattern of caudal papillae in males and the small ratio of oesophagus length:male total body length (0.1-0.16).

The diversity and evolution of nematodes (Pharyngodonidae) infecting New Zealand lizards.

Host-parasite co-evolutionary studies can shed light on diversity and the processes that shape it. Molecular methods have proven to be an indispensable tool in this task, often uncovering unseen diversity. This study used two nuclear markers (18S rRNA and 28S rRNA) and one mitochondrial (cytochrome oxidase subunit I) marker to investigate the diversity of nematodes of the family Pharyngodonidae parasitizing New Zealand (NZ) lizards (lygosomine skinks and diplodactylid geckos) and to explore their co-evolutionary history. A Bayesian approach was used to infer phylogenetic relationships of the parasitic nematodes. Analyses revealed that nematodes parasitizing skinks, currently classified as Skrjabinodon, are more closely related to Spauligodon than to Skrjabinodon infecting NZ geckos. Genetic analyses also uncovered previously undetected diversity within NZ gecko nematodes and provided evidence for several provisionally cryptic species. We also examined the level of host-parasite phylogenetic congruence using a global-fit approach. Significant congruence was detected between gecko-Skrjabinodon phylogenies, but our results indicated that strict co-speciation is not the main co-evolutionary process shaping the associations between NZ skinks and geckos and their parasitic nematodes. However, further sampling is required to fully resolve co-phylogenetic patterns of diversification in this host-parasite system.