Photo: Jordi Muntaner. Question marks: Aina Bonner

 

Challenge 7

Today this Challenge is on osteology

Knowledge of bird anatomy was in vogue among ornithologists more than a century ago. It is not so much now. The skeletal system of birds is extremely informative about how they evolved and how they work. Personally, I love bones. In this blog I will sporadically present osteological challenges, which may help us understand a little more the uniqueness and diversity of birds.

Bird wings are a great evolutionary invention. They are supported by the skeleton of the forelimb, which in birds is usually composed of the following segments:

humerus

radius-ulna

carpometacarpus (+ two small carpal bones)

proximal phalanges

distal phalanx

The bones of the first two segments are homologous to those of our arms (humerus) and forearms (radius and ulna), while those of the last three segments are the bones of the hands and wrists. The “hand” bones of birds support the primary feathers (and alula), while the secondary feathers are supported by the forearm (ulna), and the tertiary feathers by the arm (humerus). In the vast majority of birds, the design of the wings means that the carpometacarpus (the longest bone in the “hand” of birds) is shorter than the humerus. However, some birds are “rare”: All members of two orders of birds have carpometacarpi longer than their humeri. Do you know what these birds are?

 

 

 

Valora este post

Josep Antoni Alcover

Zoòleg i paleontòleg de vertebrats. Doctor en Biologia per la Universitat de Barcelona. 68 anys, casat amb Francisca Comas; dos fills, Carme i Enric. Investigador Científic del Consejo Superior de Investigaciones Científicas, adscrit a l’Institut Mediterrani d’Estudis Avançats (IMEDEA, centre mixt del CSIC i de la Universitat de les Illes Balears). Fins 2016 (8 anys) i 2020-2021, vice-director de l’IMEDEA (UIB-CSIC). Temes d’interès: Evolució dels vertebrats insulars. Endemismes insulars. Aus fòssils. Extinció d’espècies. Documentació arqueològica d’introduccions d’espècies. Biogeografia insular. Descripcions de espècies noves de vertebrats. Col·leccions científiques. Publicacions científiques en revistes internacionals i nacionals sobre vertebrats insulars, principalment de Balears i illes de la Macaronèsia. Publicacions divulgatives a revistes nacionals. Comissari de l’exposició Les Balears abans dels Humans (2000-2001, Palma, Inca, Maó, Sant Antoni de Portmany; >20.000 visitants). 10 llibres com autor, coautor o editor. Investigador Principal de 17 projectes competitius nacionals i internacionals finançats (dos per National Geographic Society), participant a altres quatre. Co-fundador i soci del Grup Balear d’Ornitologia i Defensa de la Naturalesa (GOB). President de la Societat d’Història Natural de les Balears (SHNB), anys 1994 a 1999.

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