Trypanorhyncha

Marmolejo-Guzman, Linda Yacsiri G., Iv, David, Hern, an G., andez-Mena, Castellanos-Martínez, Sheila & Aguirre-Macedo, M. Leopoldina, 2022, Linking phenotypic to genotypic metacestodes from Octopus maya of the Yucatan Peninsula, International Journal for Parasitology: Parasites and Wildlife 19, pp. 44-55 : 47-49

3.3.1. Trypanorhyncha

For the 28S rDNA, three partial sequences (995–1445 bp in length) from Kotorella pronosoma , two (1411 and 1453 bp in length) from Prochristianella sp. , and a single sequence from Eutetrarhynchus sp. (1460 bp in length) were included in an aligned dataset of 1631 bp in length, with nucleotide frequencies of A = 0.214604, C = 0.21835, G = 0.322620, and T = 0.244423. The maximum likelihood (ML) value of the tree obtained with 28S rDNA sequences was ln = – 15209.189111. The topology showed two main clades ( Fig. 4 ). The Trypanorhyncha ( Kotorella

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pronosoma , Eutetrarhynchus sp. , and Prochristianella sp. ) from O. maya are grouped in the same subclade ( Fig. 4 ). Kotorella pronosoma formed a non-monophyletic group with the genera Tentacularia , Nybelinia , Heteronybelinia , and Mixonybelinia (Bt = 100; Fig. 4 ). The Kotorella genus was non-monophyletic in our analysis since two independent groups were formed. In one group, K. pronosoma ex O. maya nested with specimens ex Syacium papillosum ( Pleuronectiformes ) and Hypanus say ( Myliobatiformes ) (Bt = 100; Fig. 4 ) without genetic differences among them; whereas Kotorella sp. and K. pronosoma ex Taeniura lymma ( Myliobatiformes ) and Bathytoshia lata ( Myliobatiformes ), respectively, nested in an independent clade (Bt = 89; Fig. 4 ). The genetic divergence between K. pronosoma from O. maya and K. pronosoma ex T. lymma and D. thetidis was 2% and 3.5%, respectively. Concerning Eutetrarhynchus sp. ex O. maya , it formed a non-monophyletic group with species of Eutetrarhynchus , Dollfusiella , Paroncomegas , and Tetrarhynchobothrium (Bt = 100); Eutetrarhynchus also did not form a monophyletic clade since the species Eutetrarhynchus pacificus is grouped with Dollfusiella martini and not with the species found in the octopus. Genetic distances ranging from 10.5% to 18.2% between Eutetrarhynchus sp. and the rest of the species in the clade. Particularly Eutetrarhynchus sp. ex O. maya differed genetically from E. pacificus by 18.2%. Prochristianella sp. formed a non-monophyletic group with Parachristianella , Mecistobothrium , Tetrarhynchobothrium , and Oncomegoides (Bt = 91; Fig. 4 ). Prochristianella sp. from O. maya grouped with Prochristianella sp. 1 ex Sphyrna tiburo

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( Carcharhiniformes ), showing 1% of genetic distance ( Fig. 4 ).

Regarding the 18S rDNA, three partial sequences (545–552 bp in length) from Prochristianella sp. , two (558 bp in length) from Eutetrarhynchus sp. , two (545 and 553 bp in length) from Kotorella pronosoma , and a single sequence (555 bp in length) from Nybelinia sp. were aligned in a dataset of 1524 bp with 59 additional sequences of Trypanorhyncha (nucleotide frequencies A = 0.237116, C = 0.216641, G = 0.284535, and T = 0.261707). The ML value of the 18S rDNA tree was ln = – 7987.787948. The resulting phylogenetic tree showed that octopus cestodes grouped in four different clades ( Fig. 5 ). Plerocercoids of Nybelinia sp. formed a non-monophyletic group with Tentacularia , Heteronybelinia , Kotorella , and Mixonybelinia (Bt = 100; Fig. 5 ). Particularly, Nybelinia sp. ex O. maya grouped with Nybelinia africana (GenBank ID: DQ642948) (Bt = 43) showing a 3% of genetic distance ( Fig. 5 ). Kotorella pronosoma ex O. maya grouped with adult stages of the same species found in H. say and B. lata (0% and 2.7% of interspecific genetic distance, respectively), but did not cluster with Kotorella sp. ex T. lymma , which showed 2.8% of interspecific genetic divergence with respect to K. pronosoma ex O. maya . Concerning Eutetrarhynchus ex O. maya , this parasite grouped with Dollfusiella , Paroncomegas , and Tetrarhynchobothrium with a high support value (Bt = 90), showing an interspecific genetic distance ranging from 8.9% to 12.9% among these species ( Fig. 5 ). Finally, Prochristianella sp. ex O. maya formed a highly supported group (Bt = 100) with specimens of the same genus infecting S. tiburo , Maculabatis pastinacoides ( Myliobatiformes ), and Prochristianella macracantha ex T. lymma , showing an interspecific genetic distance of 2.4% and 0.7%, respectively, among these species ( Fig. 5 ).

Figures

Fig. 4. Phylogenetic tree based on the Maximum Likelihood (ML) analysis of the species of the Order Trypanorhyncha found in Octopus maya constructed on partial large subunit ribosomal gene (28S) (likelihood = – 15209.189111). Bootstrap support values for ML are provided at the nodes; ex = host; the stage of development of the cestode in parentheses.

Fig. 5. Phylogenetic tree based on the Maximum Likelihood analysis of the species of the Order Trypanorhyncha found in Octopus maya constructed on partial small subunit ribosomal gene (18S) (likelihood = – 7987.787948). Bootstrap support values for ML are provided at the nodes; ex = host; the stage of development of the cestode in parentheses.