Musculoskeletal and tendinous details of selected anomalies in the locomotor system of anurans

SOLIZ MÓNICA C.; ABDALA, V

Anatomical Record

John Wiley and Sons Inc

Año: 2024 p. 1 - 24

Previous studies on anuran anomalies predominantly examine isolated cases orfocus on external and skeletal features. Our study analyzes a comprehensivesample collected from 1991 to 2017, examining the muscle-tendon system in24 anuran species across adult, juvenile, and metamorphic stages. This extensivesample size allows us to investigate consistent anomaly patterns across differentdevelopmental stages and anuran families, exploring potential common develop-mental or genetic factors. Our detailed anatomical examination, encompassingmusculature, tendons, and skeletal structures, revealed that 21% of the speci-mens displayed anomalies, a noteworthy finding considering the extensive sam-ple size and duration of the studied sample. Of these anomalies, 17% affectedthe locomotor system, predominantly in the upper limbs. Key anomaliesincluded, forelimbs and hindlimbs brachydactyly, rotation in forelimbs, partialkyphotic lordosis, and scoliosis. Notably, the digit 4 in the forelimbs and digits4 and 5 in the hindlimbs were particularly susceptible to teratogenic effects, indi-cating possible prolonged exposure during development. Our study also uncov-ered combinations of anomalies and identified a phenotype similar to Polandsyndrome. The findings validate the “Logic of Monsters” (LoMo theory) byAlberch, although the name itself may not be deemed appropriate, showing thatdevelopmental disruptions in tetrapods are not random but follow distinctsequences and patterns. The name, while unfortunate, accurately reflects theunusual nature of these developmental anomalies. This contributes to the evolv-ing “Evo-Devo-Path” framework, highlighting the study's importance in under-standing developmental disruptions in tetrapods.