caa a22 4500 463255224 CHVBK 20180405153352.0 cr unu---uuuuu 170326e20071201xx s 000 0 eng 10.1007/s00435-007-0042-4 doi (NATIONALLICENCE)springer-10.1007/s00435-007-0042-4 Chaetal arrangement in Orbiniidae (Annelida, Polychaeta) and its significance for systematics [Elektronische Daten] [Sabine Hoffmann, Harald Hausen] The systematic position of Orbiniidae within Polychaeta is still uncertain. In order to provide additional comparative data, we investigated the chaetal arrangement in this family, which is considered valuable for polychaete systematics. Specimens of Scoloplos armiger, Orbinia latreillii, and Pettibonella multiuncinata were examined by SEM and serial sections analysed by computer aided 3D-reconstructions. The obtained data suggest that the chaetal arrangement of Orbiniidae resembles that of other sedentary polychaetes in only a few respects. Transverse rows are only present in the main, anterior part of the chaetal patches of thoracic neuropods. The position of the formative site indicates homology with the transverse rows of several sedentary polychaete taxa. The chaetal patches thus differ significantly from those known in Apistobranchidae. Independent rows with an own caudal formative site, which run along the caudoventral edge of the chaetal patches, resemble the neuropodial ventral longitudinal rows known in Spionidae and related taxa. The abdominal neuropodia of S. armiger and O. latreillii bear longitudinal rows of chaetae. These are reorientated during ontogenetic chaetiger transformation and become the transverse rows of the thoracic chaetal patches. 3D reconstruction of S. armiger revealed that the notopodial chaetal bundles are organized in rows as well. Notopodia and abdominal neuropodia bear deep reaching supportive chaetae. They are the first chaetae formed during neuropodial development and reside dorsally to the longitudinal row of capillary chaetae. Neither position nor structure indicates homology with the supportive chaetae of other sedentary polychaetes. Spionidae and related taxa are thus the only sedentary polychaetes, which specifically resemble Orbiniidae in certain aspects of their chaetal arrangement. Springer-Verlag, 2007 Chaetae nationallicence Parapodia nationallicence Supportive chaetae nationallicence 3D-reconstruction nationallicence Hoffmann Sabine Institute for Biology, Animal Systematics and Evolution, Free University Berlin, Königin-Luise-Str. 1-3, 14195, Berlin, Germany aut Hausen Harald Institute for Biology, Animal Systematics and Evolution, Free University Berlin, Königin-Luise-Str. 1-3, 14195, Berlin, Germany aut Zoomorphology Springer-Verlag 126/4(2007-12-01), 215-227 0720-213X 126:4<215 2007 126 435 https://doi.org/10.1007/s00435-007-0042-4 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00435-007-0042-4 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Hoffmann Sabine Institute for Biology, Animal Systematics and Evolution, Free University Berlin, Königin-Luise-Str. 1-3, 14195, Berlin, Germany aut NATIONALLICENCE 700 1- Hausen Harald Institute for Biology, Animal Systematics and Evolution, Free University Berlin, Königin-Luise-Str. 1-3, 14195, Berlin, Germany aut NATIONALLICENCE 773 0- Zoomorphology Springer-Verlag 126/4(2007-12-01), 215-227 0720-213X 126:4<215 2007 126 435 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer