TY - ABST

T1 - Larval Myogenesis in the Articulate Brachiopod Argyrotheca cordata (Risso, 1826)

AU - Altenburger, Andreas

AU - Wanninger, Andreas Wilhelm Georg

N1 - Volumne: 269

PY - 2008

Y1 - 2008

N2 - Brachiopoda is a metazoan phylum with a fossil record dating back tothe lower Cambrium and comprises over 12,000 extinct and 400 recentspecies. Despite some recent progress using mainly palaeontological andmolecular datasets, the discussion concerning the phylogenetic positionof Brachiopoda remains unsettled. While some classic analyses employingmorphological data assign Brachiopoda to Deuterostomia, recent moleculardata propose a sister group relationship of Spiralia to a cladeLophophorata that unites Brachiopoda, Ectoprocta, and Phoronida. Tocontribute new developmental and micromorphological data to thisdebate, we investigated muscle formation in larvae of the brooding articulatebrachiopod Argyrotheca cordata using immunocytochemistry combinedwith confocal laser scanning microscopy. Full grown larvae arethree-lobed and show two pairs of bristle bundles. During larval development,the first anlagen of the musculature develop in the bristle pouchesand the pedicle lobe. Late stage larvae show a network of longitudinalmuscles running from the apical to the pedicle lobe as well as transversalmuscles situated in the apical lobe. Strong muscles attach to both thebristles and the pedicle lobe. Our work reveals only few similaritiesbetween the larval myoanatomy and myogenesis of A. cordata and thehitherto investigated phoronid and ectoproct species, which may account for an early distinct evolutionary pathway of the general ontogeny

AB - Brachiopoda is a metazoan phylum with a fossil record dating back tothe lower Cambrium and comprises over 12,000 extinct and 400 recentspecies. Despite some recent progress using mainly palaeontological andmolecular datasets, the discussion concerning the phylogenetic positionof Brachiopoda remains unsettled. While some classic analyses employingmorphological data assign Brachiopoda to Deuterostomia, recent moleculardata propose a sister group relationship of Spiralia to a cladeLophophorata that unites Brachiopoda, Ectoprocta, and Phoronida. Tocontribute new developmental and micromorphological data to thisdebate, we investigated muscle formation in larvae of the brooding articulatebrachiopod Argyrotheca cordata using immunocytochemistry combinedwith confocal laser scanning microscopy. Full grown larvae arethree-lobed and show two pairs of bristle bundles. During larval development,the first anlagen of the musculature develop in the bristle pouchesand the pedicle lobe. Late stage larvae show a network of longitudinalmuscles running from the apical to the pedicle lobe as well as transversalmuscles situated in the apical lobe. Strong muscles attach to both thebristles and the pedicle lobe. Our work reveals only few similaritiesbetween the larval myoanatomy and myogenesis of A. cordata and thehitherto investigated phoronid and ectoproct species, which may account for an early distinct evolutionary pathway of the general ontogeny

M3 - Conference abstract in journal

SP - 1478

JO - Journal of Morphology

JF - Journal of Morphology

SN - 0362-2525

IS - 12

Y2 - 17 August 2008 through 21 August 2008

ER -