ORIGINAL ARTICLE The Ossification of the Pectoral Girdle and Wing Skeleton of the Quail (Coturnix coturnix japonica) A. F. Pourlis 1 * and J. Antonopoulos 2 Addresses of authors: 1 Laboratory of Anatomy, Histology and Embryology, School of Veterinary Medicine, University of Thessaly PO Box 199, Karditsa GR-43100, Greece; 2 Laboratory of Anatomy, Histology and Embryology, School of Veterinary Medicine, Aristotle University of Thessaloniki, Thessaloniki GR-54124, Greece Introduction The chronological sequence of the onset of ossification centres during the pre-hatching period has been studied in many bird species (Romanoff, 1960). Afterwards, the majority of these studies dealt with the ossification of Galliformes and most of them focused on the chicken (Rumpler, 1962; Schumacher and Wolff, 1967; Rinaldi and Caronna, 1971; Holder, 1978) and turkey (Scala et al., 1993; Maxwell, 2008; Atalgin and Ku ¨rtu ¨l, 2009) skeleton during the pre-hatching period. Information regarding the post-hatching skeletal ossifi- cation of birds is confined mainly in the fowl (Latimer, 1927; Schinz and Zangerl, 1937). Other studies described the onset of ossification centres in the fowl during the post-hatching period, with the aid of X-rays (Church and Johnson, 1964; Hogg, 1980, 1982). Apart from the chicken, the quail (Coturnix coturnix japonica) represents an avian species, which is part of the wild fauna and a domestic animal. In addition, the quail is widely used in experimental biomedical research. For this reason, it is essential to assemble a database of the morphological characteristics of this bird. Regarding the quail, Lansdown (1969) and later Pourlis et al. (1998) reported on the temporal onset of ossifica- tion centres of the wing long bones by means of Alizarin Red S (ARS) staining-light microscopy and Alcian Blue- ARS, respectively. The embryonic development of quail skeleton in staged embryos according to Zacchei’s (1961) classification has been described by Nakane and Tsudzuki (1999). However, the authors recorded with simple obser- vation of cartilage or bone, the ossification events in every stage. Comparative avian skeletal development has been examined in a phylogenetic context by Maxwell (2008). *Correspondence: Tel.: + 30 24410 66013; fax: + 30 24410 66041; e-mail: apourlis@vet.uth.gr With 5 figures Received October 2009; accepted for publication January 2011 doi: 10.1111/j.1439-0264.2011.01065.x Summary The onset of ossification centres of the pectoral girdle and wing skeleton of the quail (Coturnix coturnix japonica) has been studied in embryos and juvenile birds, which were sampled daily from the 4th day of incubation up to the 12th day after hatching. Specimens, which were cleared and were stained with Alcian Blue and Alizarin Red S, were examined at the stereomicroscope. The furcula ossified with intramembranous ossification at the 7th day of incubation. The first centres of perichondral ossification in the scapula and the coracoid bones were observed at the 7th day of incubation. In the humerus, radius and ulna, perichondral ossification was observed at the 6th day of incubation. The carpal bones were ossified between the 8th and 10th day of the post-hatching period. The 2nd metacarpal bone began to ossify at the 6th day of the post-hatching period, whereas the 3rd and 4th metacarpal bones were ossified at the 7th day of incubation. At the 9th day of incubation, ossification was observed in the 1st phalanx of the alular digit and in the phalanges of the major digit. The 2nd phalanx of the alular digit began to ossify at the 12th, whereas the phalanx of the minor digit at the 14th day of incubation. The data presented here provide useful baseline information on the normal sequential pattern of ossification in the pectoral girdle and wing skeleton in this species. Anatomia Histologia Embryologia ª 2011 Blackwell Verlag GmbH • Anat. Histol. Embryol. 40 (2011) 219–225 219