A New Species Of Serpinema (Nematoda: Camallanidae) From A Captive False Map Turtle (Graptemys pseudogeographica pseudogeographica) In Portugal

Resumo

Objectives: The genus Serpinema (Yeh, 1960) comprises parasitic nematodes of freshwater turtles. This study describes a potentially novel Serpinema species recovered from a false map turtle (Graptemys pseudogeographica pseudogeographica), based on integrated morphological and molecular data.

Materials and Methods: A false map turtle rescued with traumatic injuries underwent assisted feeding as part of clinical care. During the procedure, the animal regurgitated several nematodes, which were collected for examination. Five specimens were obtained, and DNA was extracted from one male and one female. Morphological analysis was performed using a compound microscope. PCR assays targeting cox1 and 18S rDNA were conducted using specific primers. Phylogenetic trees were inferred using the maximum likelihood method implemented in IQ-TREE.

Results: Phylogenetic analyses suggest that the collected specimens may represent a distinct species. The 18S-rDNA tree showed that the obtained sequences share a common ancestor with S. cayennensis, the only 18S-rDNA Serpinema spp. sequences available in public databases, supporting its placement within the genus. The cox1 tree reveals a well-supported monophyletic cluster composed exclusively of the obtained sequences, suggesting significant genetic divergence from previously described Serpinema spp. Morphologically, the collected specimens exhibit distinguishing features that do not overlap with those of other Serpinema spp.

Conclusions: The integration of morphological and molecular data suggests the potential existence of a novel species. Future studies should explore host-parasite interactions, transmission routes, and phylogeographic patterns.

Keywords: Serpinema sp.; false map turtle; Graptemys pseudogeographica pseudogeographica; taxonomy; Portugal.