A phylogenetic assessment of the colonisation patterns in Spauligodon atlanticus Astasio-Arbiza et al., 1987 (Nematoda: Oxyurida: Pharyngodonidae), a parasite of lizards of the genus Gallotia Boulenger: no simple answers

Abstract

Parasite taxonomy traditionally relies on morphometric and life-cycle characteristics which may not reflect complex phylogenetic relationships. However, genetic analyses can reveal cryptic species within morphologically described parasite taxa. We analysed the phylogenetic variation within the nematode Spauligodon atlanticus Astasio-Arbiza, Zapatero-Ramos, Ojeda-Rosas & Solera-Puertas, 1987, a parasite of the Canarian lizard genus Gallotia Boulenger, inferring the origin of their current association. We also attempted to determine its relationship with other Spauligodon spp. Three different markers, mitochondrial COI plus nuclear 18S and 28S ribosomal RNA, were used to estimate the evolutionary relationships between these nematodes. S. atlanticus was found to be paraphyletic, suggesting that Gallotia spp. were colonised by two independent lineages of Spauligodon. Additional analyses of other Spauligodon spp. are required for a more complete interpretation of the evolution of this genus from the Canarian archipelago and its closest taxa. Our results emphasise the importance of extensive sampling and phylogenetic studies at the intrageneric level, and highlight the limitations of a morphologically based taxonomy in these parasites.

Molecular screening of nematodes in lacertid lizards from the Iberian Peninsula and Balearic Islands using 18S rRNA sequences

“…Six hundred microlitres of lysis buffer (0.5 M Tris, 0.1 M EDTA, 2% sodium dodecyl sulphate (SDS), pH 8.0) and 5 -20 ml of proteinase K (25 mg/ml) were added to small pieces of tissue and incubated at 568C overnight. These primers have been used previously to amplify DNA of other nematodes infecting reptiles (Hasegawa et al, 2009;Jorge et al, 2011). The supernatant was transferred to new Eppendorf tubes with 600 ml of ice-cold isopropanol, frozen from 3 h to overnight, and centrifuged for 15 -30 min at 14,000 rpm at 2 48C.…”

Cryptic species unveiled: the case of the nematode Spauligodon atlanticus

“…Recently, several studies reported the discovery of cryptic species within what were considered single species, through the use of population genetics, phylogeographic or phylogenetic tools (Jorge et al. ; Nadler and Pérez‐Ponce de León ; Poulin ; Oliveira et al. ).…”

“…One recent case of possible cryptic species in parasites has been observed in the nematode genus Spauligodon , infecting endemic lizards of the genus Gallotia in the Canarian archipelago (Jorge et al. ). Spauligodon atlanticus Astasio‐Arbiza et al.…”

“…were colonized twice independently by Spauligodon nematodes (Jorge et al. ). Given the clear polyphyly of S. atlanticus revealed by both mitochondrial and nuclear genes (cytochrome oxidase subunit I and 28S ribosomal RNA, respectively), Jorge et al.…”

“…Given the clear polyphyly of S. atlanticus revealed by both mitochondrial and nuclear genes (cytochrome oxidase subunit I and 28S ribosomal RNA, respectively), Jorge et al. () proposed the separation of the species, with the eastern lineage retaining the S. atlanticus designation, since the first description of the species was from G. a . atlantica from the easternmost island (Lanzarote), while the western lineage should be considered as a new species, which has not yet been formally described.…”