Abstract South American racers of the tribe Philodryadini are a widespread and diverse group of Neotropical snakes with a complex taxonomic and systematic history. Recent studies failed to present a robust phylogenetic hypothesis for the tribe, mainly due to incomplete taxon sampling. Here we provide the most extensive molecular phylogenetic analysis of Philodryadini available so far, including 20 species (83% of the known diversity) from which six were not sampled previously. Our results reveal that Philodryadini is not monophyletic, but instead includes a central Andean clade formed by Philodryas simonsii, P. tachymenoides, and P. amaru, and a southern and cis-Andean clade including all remaining philodryadines. This discovery requires resurrection of two genera as well as erection of a new tribe of Xenodontinae for the central Andean clade. Within the southern and cis-Andean radiation, our analyses resolve a basal dichotomy separating two main lineages: Clade A, containing the Common Green Racers P. laticeps and P. viridissima and the South American Vine snakes P. georgeboulengeri and P. argentea; and Clade B, including the remaining species of Philodryas sensu stricto. We resurrect the genera Chlorosoma and Xenoxybelis to better represent the monophyly of lineages within the southern and cis-Andean clade.

Ochetosoma heterocoelium Travassos, 1921 is a parasite that has been identified in snakes from different locations in Colombia and is considered of veterinary importance. Here, we present a redescription based on morphological traits of juveniles and adults. Parasite burden of O. heterocoelium in the host varied between 3-207 individuals which were localized in the oral cavity of snakes, causing damage that range from small infections to mechanical obstruction of the esophagus and Jacobson's organ. The low levels of abundance and prevalence in the snakes Leptodeira septentrionalis, Bothriechis schlegelli, Bothrops asper and Porthidium nasutum coming from the localities of Maceo, Vegachí and Acandí regions, suggest that the parasite is not a threat to the snakes of Colombia. We propose a treatment program that consists of manual removal of Digenea as well as treating snakes with antihelminthics, the applaying of soft antiseptics and monitoring recovery. The prevalence of O. heterocoelium was established in new regions, namely Middle Magdalena, Valle de Aburrá, Urabá Chocoano and northern Colombia. This extends the known geographical distribution from Brazil and Venezuela. New hosts were also identified: Atractus lasallei, Bothriechis schlegelli, Bothrops asper, Chironius carinatus, Leptodeira septentrionalis, Leptophis ahaetulla and Porthidium nasutum.

Se identifica Ochetosoma heterocoelium Travassos, 1921 como un parásito de importancia veterinaria en ofidios de diferentes localidades de Colombia y se redescribe con base en las características morfológicas de individuos juveniles y adultos. La carga parasitaria de O. heterocoelium varió de 3-207 individuos alojados en la cavidad bucal de los ofidios, causando desde infecciones leves hasta obstrucción mecánica en el esófago y órgano de Jacobson. Los bajos valores de abundancia y prevalencia en las localidades de Maceo, Vegachí y Acandí y en los ofidios Leptodeira septentrionalis, Bothriechis schlegelii, Bothrops asper y Porthidium nasutum sugieren que el parásito no es una amenaza para los ofidios de Colombia. El tratamiento propuesto consiste en la remoción manual de los digeneos junto con la desparasitación de los ofidios con Praziquantel 7.5 mg /kg PO, en 2 tomas con 15 días de diferencia, la aplicación de antisépticos y el seguimiento de su recuperación. Se identifican 4 zonas de distribución de O. heterocoelium: Magdalena medio, Valle de Aburrá, Urabá Chocoano y la zona norte de Colombia; se amplía así su distribución geográfica desde Brasil y Venezuela. Como nuevos hospederos se registran Atractus lasallei, Bothriechis schlegelii, Bothrops asper, Chironius carinatus, Leptodeiraseptentrionalis, Leptophis ahaetulla y Porthidium nasutum.