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Although landing behaviour in anurans differs significantly among species, a take‐off behaviour seems to be largely conserved in the evolution of frogs and toads. The ancestral mode of landing is hypothesized to involve the body crash‐landing on the substrate, after which the anuran cycles the limbs forward and then backward to their resting position. The part of the body that first contacts the substrate may vary among taxa. The limbs and pectoral girdle muscles as well as those of the caudopelvic region, involved with landing and take‐off behaviours, are investigated. The existence of a relationship exists between myology and different take‐off and landing behaviours is explored. The results suggest that most of the muscles involved in both take‐off and landing are conserved morphologically, with only few differing, depending on the locomotor behaviour. Two muscles tend to be longer; the m. coracobrachialis, which is involved with landing, and the m. coccygeosacralis, related to the take‐off. [ABSTRACT FROM AUTHOR]

One of the most remarkable hand movements is grasping. This ability has been repetitively associated with the evolution of the human lineage towards the development of technology. Besides mammals, other tetrapods have also evolved significant, and in some cases surprising, forelimb prehensile capabilities. In this study, we present a qualitative analysis of the carpal bones in diverse lizard taxa. Our main goal is to make a survey of the carpal morphology of different squamatans and to interpret its variability in the context of both lizard skilled forelimb movements and the evolutionary history of Squamata. [ABSTRACT FROM AUTHOR]

We present the ontogeny of the integrated musculoskeletal complex that comprises the pelvic girdle and hind limbs of anurans. Our histological data show that the pelvic girdle originates from a single mesenchymatic condensation. The tissue differentiation sequence is cartilage, muscle and tendon. The intrusion of the ischiadic nerve into the limb bud is produced very early in ontogeny. The pre-cartilage appears in the pre-motile stage. Therefore, the nerve produces a movement analogous to the 'embryonic motility' that would induce the emergence of the pre-cartilage. The acetabulum is the first of all cavitation processes to form, the second one being the knee. The acetabulum appears before the muscles are mature, although it has been stressed that the muscle contraction maintains joint progenitors committed to their fate. Our data indicate an explosive differentiation of all 11 muscular masses together. We provide three new characters that support the monophyly of Hyloides, Acosmanura and Neobatrachia. [ABSTRACT FROM AUTHOR]

Jerez, A., Mangione, S. and Abdala, V. 2010. Occurrence and distribution of sesamoid bones in squamates: a comparative approach.— Acta Zoologica (Stockholm) 91: 295–305 Sesamoids are defined as skeletal elements that develop within a continuous band of regular dense connective tissue (tendon or ligament) adjacent to an articulation or joint. In this work, we discuss developmental data on two squamate species, provide data on the onset of the squamate sesamoids and the muscles they are associated to. Our results show that Mabuya mabouya and Liolaemus albiceps exhibited rather similar ontogenetic patterns and that the first sesamoids appear in embryos. The ossifying sesamoid timing is different between M. mabouya and L. albiceps, being faster in the former. In adults, we found 41 sesamoids, considering both fore and hindlimbs. We did not find any intrataxonomic differences, or any differences between the right and left side of the specimens in relation to the sesamoid presence. We recognize four types of sesamoids: (1) embedded sesamoids; (2) interosseus sesamoids; (3) glide sesamoids; and (4) supporting sesamoids. A table is included with a preliminary survey of the sesamoid distribution pattern in 10 Squamate clades. [ABSTRACT FROM AUTHOR]