Lukas, P. & P. H. dos Santos Dias

Larval morphology of Discoglossus scovazzi (Amphibia: Anura: Alytidae) and its phylogenetic implications. pp. 97-103 plus Supplementary material.

Abstract. Discoglossus scovazzi, an endemic North African species within Alytidae, has long been understudied in terms of its larval morphology. This work presents a comprehensive description of its tadpole (Gosner stages 20–28), based on 52 specimens reared under controlled laboratory conditions. We document the external morphology, coloration, and cranial and hyobranchial musculature using high-resolution imaging and histological data. The tadpole exhibits an elliptical body shape, an anteroventrally directed oral disc with a labial tooth row formula of 2/3(1), and distinct pigmentation patterns. Muscle reconstructions revealed 34 cranial and branchial muscles, including the presence of the m. tympanopharyngeus, a newly reported autapomorphy. Through phylogenetic optimization, we identify five synapomorphies supporting the Costata clade, and three autapomorphies unique to D. scovazzi. These findings not only refine the morphological diagnosis of D. scovazzi but also enhance our understanding of character evolution within basal anurans. The inclusion of this species broadens the morphological dataset for Alytidae and underlines the importance of larval characters in phylogenetic inference. Our results underscore the need for further research on larval morphology across understudied taxa to illuminate early anuran diversification.

Key words. Morphology, musculature, development, phylogeny, synapomorphy, tadpole.