The flexor tendons in the didelphid manus

ABDALA, V.; MORO, S.; FLORES, D.A.

MASTOZOOLOGí­A NEOTROPICAL

SAREM

Lugar: Mendoza; Año: 2006 vol. 13 p. 193 - 204

0327-9383

Tetrapods have flexor tendons in the palmar surface of the manus that transmit forces generated by superficial and deep forearm muscles to the digits. Two patterns (P and L) of tendinous connections among the deep layer of the forearm muscles and the digits have been described, one of which (pattern P) shows an empirical correlation with some grade of arboreality. In this article, we focused on the anatomical design of the tendons of the deep layer of the palmar surface of the didelphids manus, and associated muscles. Our objectives are: 1) to describe the pattern found in all taxa of the great didelphid clade, 2) to assign the design that we found to the L or P pattern, and 3) to discuss our results in the context of the latest available phylogenetic hypotheses proposed for those taxa. All of the didelphids we dissected posses the P pattern. As we compared the tendinous and myological structures, we found that some of the myological differences we describe could have important phylogenetic implications. We selected 10 characters, mapped them on marsupial phylogenies, and discovered six more synapomorphies supporting clades alreasy proposed by other researchers.