Life on the edge: a review of Cycloramphidae tadpoles (Amphibia; Anura) with comments on the evolution of semiterrestrial tadpoles

DIAS, PEDRO HENRIQUE DOS SANTOS; VERA CANDIOTI, F; FARES SABBAG, A; COLACO, G; DA SILVA, H.; HADDAD, CFB; CARVALHO-E-SILVA, ANA MARIA PAULINO TELLES DE; GRANT, T

JOURNAL OF ZOOLOGICAL SYSTEMATICS AND EVOLUTIONARY RESEARCH

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2021

0947-5745

The evolutionary success of anurans can be partially explained by the occurrence offree-livinglarvae. Tadpoles occupy several distict habitats, including the terrestrialenvironment. Semiterrestriality appears to have evolved seven times in anurans, andtadpoles of distantly related lineages have converged in a set of phenotypic characters,such as a depressed body, ventral mouth, massive, well-keratinizedand laterallycompressed jaw sheaths, low fins, and well-developedhind limbs. The semiterrestrialtadpoles of the South American family Cycloramphidae remain poorly studied. In thiswork, we perform a comparative analysis of the external and internal morphology ofthese larvae, we comment on the systematic and evolutionary implications for thefamily, and finally, we discuss the convergent evolution of semiterrestrial tadpoles inanurans. We studied the external, buccopharyngeal, and musculoskeletal morphologyof semiterrestrial tadpoles of 14 species of Cycloramphidae. These tadpoles are highlymodified and present several character-statesassociated with semiterrestrial life.Most of them are unique and restricted to the family, such as the novel configurationof the muscles subarcualis rectus I, rectus abdominis, and levator arcuum branchialiumIII. We propose 13 new synapomorphies for Cycloramphidae and one for Thoropa.The presence of similar, homoplastic, character-statesin all semiterrestrial tadpolesof unrelated phylogenetic lineages seems to suggest that these character-statesareadaptations for semiterrestriality.