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Development of the paired fins in the paddlefish, Polyodon spathula.
J Morphol 2004; 261(3):334-44JM

Abstract

In Polyodon spathula, the pectoral fin radials, with the exception of the metapterygium, are derived from the decomposition of a single continuous cartilage fin plate that is continuous with the scapulocoracoid. This cartilage sheet develops two interior splits to form three precursor pieces, and these decompose in a predictable way to generate the propterygium and radials. The metapterygium is an extension of the scapulocoracoid that segments off of it during early development. To our knowledge, this has not been reported for acipenserids or other basal actinopterygians. In teleosts, the proximal radials also develop from the "break up" of an initially continuous paddle-like sheet of cartilage along the posterior edge of the scapulocoracoid, and in Polypterus and sharks a similar pattern holds. Thus, the pattern observed in Polyodon may represent the basal developmental condition for the gnathostome pectoral fin. The process underlying development of the superficially similar cartilages of the pelvic and pectoral fins is different. In the pectoral fin, the metapterygium is segmented off of the scapulocoracoid and other radials form from the decomposition of the cartilage plate. In contrast, individual rod-like basipterygial elements form in a close one-to-one correspondence with the middle radials of the pelvic fin, but later fuse to form an anterior element that is branched in appearance. To evaluate further claims of similarity among the pectoral and pelvic fin elements of various fishes, the course of the development of these structures must be observed. The pectoral fin and girdle in Polyodon ossifies in a different sequence than that proposed as ancestral (and highly conserved) for actinopterygians: the supracleithrum ossifies significantly before the cleithrum. The later ossification of the cleithrum in Polyodon may be related to the primary use of the caudal fin vs. the pectoral fins in their locomotion.

Authors+Show Affiliations

Department of Biology, University of South Dakota, Vermillion, South Dakota 57069, USA. pmabee@usd.eduNo affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

15281061

Citation

Mabee, Paula M., and Michael Noordsy. "Development of the Paired Fins in the Paddlefish, Polyodon Spathula." Journal of Morphology, vol. 261, no. 3, 2004, pp. 334-44.
Mabee PM, Noordsy M. Development of the paired fins in the paddlefish, Polyodon spathula. J Morphol. 2004;261(3):334-44.
Mabee, P. M., & Noordsy, M. (2004). Development of the paired fins in the paddlefish, Polyodon spathula. Journal of Morphology, 261(3), pp. 334-44.
Mabee PM, Noordsy M. Development of the Paired Fins in the Paddlefish, Polyodon Spathula. J Morphol. 2004;261(3):334-44. PubMed PMID: 15281061.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Development of the paired fins in the paddlefish, Polyodon spathula. AU - Mabee,Paula M, AU - Noordsy,Michael, PY - 2004/7/29/pubmed PY - 2005/1/20/medline PY - 2004/7/29/entrez SP - 334 EP - 44 JF - Journal of morphology JO - J. Morphol. VL - 261 IS - 3 N2 - In Polyodon spathula, the pectoral fin radials, with the exception of the metapterygium, are derived from the decomposition of a single continuous cartilage fin plate that is continuous with the scapulocoracoid. This cartilage sheet develops two interior splits to form three precursor pieces, and these decompose in a predictable way to generate the propterygium and radials. The metapterygium is an extension of the scapulocoracoid that segments off of it during early development. To our knowledge, this has not been reported for acipenserids or other basal actinopterygians. In teleosts, the proximal radials also develop from the "break up" of an initially continuous paddle-like sheet of cartilage along the posterior edge of the scapulocoracoid, and in Polypterus and sharks a similar pattern holds. Thus, the pattern observed in Polyodon may represent the basal developmental condition for the gnathostome pectoral fin. The process underlying development of the superficially similar cartilages of the pelvic and pectoral fins is different. In the pectoral fin, the metapterygium is segmented off of the scapulocoracoid and other radials form from the decomposition of the cartilage plate. In contrast, individual rod-like basipterygial elements form in a close one-to-one correspondence with the middle radials of the pelvic fin, but later fuse to form an anterior element that is branched in appearance. To evaluate further claims of similarity among the pectoral and pelvic fin elements of various fishes, the course of the development of these structures must be observed. The pectoral fin and girdle in Polyodon ossifies in a different sequence than that proposed as ancestral (and highly conserved) for actinopterygians: the supracleithrum ossifies significantly before the cleithrum. The later ossification of the cleithrum in Polyodon may be related to the primary use of the caudal fin vs. the pectoral fins in their locomotion. SN - 0362-2525 UR - https://www.unboundmedicine.com/medline/citation/15281061/Development_of_the_paired_fins_in_the_paddlefish_Polyodon_spathula_ L2 - https://doi.org/10.1002/jmor.10253 DB - PRIME DP - Unbound Medicine ER -