On the anuran muscle pulmonum proprius

Abstract

The present contribution provides a systematic survey on the variation of the musculus pulmonum proprius within Anura. Evidence is contrary to previous works that presented the muscle as an enigmatic feature present only in the family Pipidae. Although having different sites of origin, the m. pulmonum proprius was observed in all examined anurans. The muscle originates at the level of the transverse processes of the fourth vertebra in the neobatrachian families Bufonidae, Calyptocephalellidae, Ceratophryidae, Cycloramphidae, Dendrobatidae, Hylidae, Hylodidae, Leiuperidae, Leptodactylidae, Mantellidae, Microhylidae, Ptychadenidae and Ranidae. In Bombina variegata (Bombinatoridae) the origin of the muscle shifts caudally at the level of the transverse process of the sacral vertebra and, in Pipidae, it originates either at the ilium (Xenopus) or the femur (Pipa). Features of the m. pulmonum proprius do not vary in species with different modes of locomotion within Neobatrachia and there is no sexual dimorphism in this muscle. It is absent in the genera Salamandra (Caudata) and Chthonerpeton (Gymnophiona). Pending verification in Leiopelmatidae, the presence of m. pulmonum proprius may be considered as a previously unknown anuran synapomorphy.

The suction mechanism of the pipid frog, Pipa pipa (Linnaeus, 1758)

“…Dorsally, a “diaphragm” muscle ( M. pulmonum proprius : Beddard, ), seems to be functionally similar to the M. transversus pharyngeus et abdominis of Sokol (). Alcalde () reviewed the distribution, structure, and possible function of the M. pulmonum proprius , clarifying its distinction from transversus fibers, and noting the shift of its origin from the ilium in Xenopus to the femur in P. pipa . In P. pipa it consists of a thin sheet of fibers that extends from a short section near the middle of the dorsal surface of the femur immediately lateral to the insertion of the gluteus ( M. iliacus externus of Dunlap, and Prikryl, Aerts, Haveloková, Herrel, & Rocek, ).…”

“…We use the name M. retractor pharyngeus for the parts of the muscle that attach to the buccopharyngeal lining in P. pipa to reflect its probable function, possibly both in ventilation and suction feeding. The parts of the muscle that attach to the lung would remain as the M. pulmonum proprius (Alcalde, ). We think it unlikely that either group of muscle fibers plays any significant role in swimming, as suggested by Prikryl et al (), but it is possible that they aid femoral protraction during rapid descent from the water surface following ventilation cycles in P. pipa .…”

The suction mechanism of the pipid frog, Pipa pipa (Linnaeus, 1758)

“…Dorsally, a “diaphragm” muscle ( M. pulmonum proprius : Beddard, ), seems to be functionally similar to the M. transversus pharyngeus et abdominis of Sokol (). Alcalde () reviewed the distribution, structure, and possible function of the M. pulmonum proprius , clarifying its distinction from transversus fibers, and noting the shift of its origin from the ilium in Xenopus to the femur in P. pipa . In P. pipa it consists of a thin sheet of fibers that extends from a short section near the middle of the dorsal surface of the femur immediately lateral to the insertion of the gluteus ( M. iliacus externus of Dunlap, and Prikryl, Aerts, Haveloková, Herrel, & Rocek, ).…”

“…We use the name M. retractor pharyngeus for the parts of the muscle that attach to the buccopharyngeal lining in P. pipa to reflect its probable function, possibly both in ventilation and suction feeding. The parts of the muscle that attach to the lung would remain as the M. pulmonum proprius (Alcalde, ). We think it unlikely that either group of muscle fibers plays any significant role in swimming, as suggested by Prikryl et al (), but it is possible that they aid femoral protraction during rapid descent from the water surface following ventilation cycles in P. pipa .…”

The suction mechanism of the pipid frog, Pipa pipa (Linnaeus, 1758)

“…Dorsally, a “diaphragm” muscle ( M. pulmonum proprius : Beddard, ), seems to be functionally similar to the M. transversus pharyngeus et abdominis of Sokol (). Alcalde () reviewed the distribution, structure, and possible function of the M. pulmonum proprius , clarifying its distinction from transversus fibers, and noting the shift of its origin from the ilium in Xenopus to the femur in P. pipa . In P. pipa it consists of a thin sheet of fibers that extends from a short section near the middle of the dorsal surface of the femur immediately lateral to the insertion of the gluteus ( M. iliacus externus of Dunlap, and Prikryl, Aerts, Haveloková, Herrel, & Rocek, ).…”

“…We use the name M. retractor pharyngeus for the parts of the muscle that attach to the buccopharyngeal lining in P. pipa to reflect its probable function, possibly both in ventilation and suction feeding. The parts of the muscle that attach to the lung would remain as the M. pulmonum proprius (Alcalde, ). We think it unlikely that either group of muscle fibers plays any significant role in swimming, as suggested by Prikryl et al (), but it is possible that they aid femoral protraction during rapid descent from the water surface following ventilation cycles in P. pipa .…”

The suction mechanism of the pipid frog, Pipa pipa (Linnaeus, 1758)

“…Dorsally, a “diaphragm” muscle ( M. pulmonum proprius : Beddard, ), seems to be functionally similar to the M. transversus pharyngeus et abdominis of Sokol (). Alcalde () reviewed the distribution, structure, and possible function of the M. pulmonum proprius , clarifying its distinction from transversus fibers, and noting the shift of its origin from the ilium in Xenopus to the femur in P. pipa . In P. pipa it consists of a thin sheet of fibers that extends from a short section near the middle of the dorsal surface of the femur immediately lateral to the insertion of the gluteus ( M. iliacus externus of Dunlap, and Prikryl, Aerts, Haveloková, Herrel, & Rocek, ).…”

“…We use the name M. retractor pharyngeus for the parts of the muscle that attach to the buccopharyngeal lining in P. pipa to reflect its probable function, possibly both in ventilation and suction feeding. The parts of the muscle that attach to the lung would remain as the M. pulmonum proprius (Alcalde, ). We think it unlikely that either group of muscle fibers plays any significant role in swimming, as suggested by Prikryl et al (), but it is possible that they aid femoral protraction during rapid descent from the water surface following ventilation cycles in P. pipa .…”