The combined use of molecular and microscopic techniques has become an increasingly common and efficient practice for the taxonomic and evolutionary understanding of single-celled parasites such as haemogregarines. Based on this integrative approach, we characterized Hepatozoon found in Helicops angulatus snakes from the Eastern Amazonia, Brazil. The gamonts observed caused cell hypertrophy and were extremely elongated and, in some cases, piriform (mean dimensions: 25.3 ± 1.9 × 8.6 ± 1.3 μm). These morphological features correspond to Hepatozoon carinicauda, described 50 years ago in the snake Helicops carinicaudus in the southeast region of Brazil. Phylogenetic and genetic divergence analyses, performed with the sequence obtained from the amplification of a 590 bp fragment of the 18S rRNA gene, revealed that Hepatozoon in He. angulatus differed from the other lineages retrieved from GenBank, and was clustered singly in both the phylogenetic tree and the haplotype network. The integration of these data allowed the identification of H. carinicauda in a new aquatic host, and increased the knowledge of its geographical distribution. Therefore, the present study included the first redescription of a Hepatozoon species in a snake from the Brazilian Amazon.

Centrorynchus nahuelhuapensis n. sp. is described from the intestine of Strix rufipes, the rufous-legged owl, in Patagonia, Argentina. This species is characterized by the presence of 31–33 hook rows with 16–17 hooks per row, distributed as follows: 5 true hooks, 4 transitional hooks with 4 alate processes, more evident in the first three, 7–8 spiniform hooks, and three cement glands. It differs from most members of the genus by having a filiform body, the arrangement and size of the hooks, the number of cement glands, and egg size. Part of the SSU and LSU genes were sequenced and compared to those in GenBank. Sequences are most similar to other species of Centrorhynchus, supporting their placement within this genus. We present the first molecular study for a species of Centrorhynchus from South America. Additionally, it is the second species of the genus described in Argentina, and the first species of a terrestrial acanthocephalan from a bird in Patagonia.