Fig 1.
A comparison of embryo age and stages of development between northern bobwhite quail (Colinus virginianus), Japanese quail (Coturnix japonica), blue-breasted quail (Synoicus chinensis), and the domestic chicken (Gallus gallus domesticus), during incubation.
Table 1.
Comparison of developmental stages of California quail (Callipepla californica), northern bobwhite quail (Colinus virginianus), Japanese quail (Coturnix japonica), blue-breasted quail (Synoicus chinensis), and domestic chicken (Gallus gallus domesticus).
Fig 2.
The first 60 hours (Stages 1–6) of California valley quail embryonic development.
(A) Stage 1, blastoderm showing. (B) Stage 2, initial streak develops. (C) Stage 3, intermediate streak. (D) Stage 4, primitive streak with Hensen’s node. (E) Stage 5, head -process at anterior end of streak near the center of pellucida area. (F) Stage 6, head-fold, somites not yet visible.
Fig 3.
Stages 7–10 (30–54 h) of the California valley quail embryological stages of development.
(A) Stage 7, one somite pair visible. (B) Stage 8, four somite pairs with blood islands present. (C) Stage 9, seven somite pairs with primordia of the heart. (D) Stage 10, 10 somite pairs and 3 brain vesicles visible.
Fig 4.
Stages 11–14 (52–60 h) of the California valley quail’s embryological stages of development.
(A) Stage 11, 13 somite pairs visible. (B) Stage 12, 16 somite pairs visible. Telencephalon, optic vesicles, and auditory pit visible. (C) Stage 13, 19 somite pairs present. Telencephalon and heart more prominent than previous stage. (D) Stage 14, 22 somite pairs present. Optic lens, and Rathke’s pouch can be identified.
Fig 5.
Stages 15–18 (66–84 h) of the California valley quail’s embryological stages of development.
(A) Stage 15, 24 somite pairs present. Optic cup and double contour has formed. (B) Stage 16, 26–28 somite pairs present. (C) Stage 17, nasal pits are visible and amnion extends toward trunk. (D) Stage 18, first appearance of wing-bud. Amnion enclosed except for small oval on the trunk.
Fig 6.
Stages 19–22 (90–120 h) of the California valley quail’s embryological stages of development.
(A) Stage 19, limb buds are slightly enlarged, and maxillary process has become distinct. (B) Stage 20, wing-buds are longer than leg-buds. (C) Stage 21, wing- and leg-buds slightly asymmetrical and enlarged. (D) Stage 22, posterior contours of leg- and wing-buds are steeper than anterior contours.
Fig 7.
Stages 23–26 (114–144 h) of the California valley quail’s embryological stages of development.
(A) Stage 23, anterior and posterior contours of limb-buds run parallel. (B) Stage 24, limbs have lengthened and are longer than wide. (C) Stage 25, all visceral protuberances have fused together and flattened. (D) Stage 26, wings bent at elbow and knee joints distinct.
Fig 8.
Stages 27–30 (6–11 d) of the California valley quail’s embryological stages of development.
(A) Stage 27, digits are concave, and 4 toes are conspicuous. (B) Stage 28, wing tip and digital plate are more angular and webbing between digits is more concave. (C) Stage 29, elbow joint is more pronounced. (D) Stage 30, egg tooth is present.
Fig 9.
Stages 31–35 (10–14 d) of the California valley quail’s embryological stages of development.
(A) Stage 31, primordia of claws. (B) Stage 32, 2 dorsal rows of pigmentation on either side of spine. (C) Stage 33, 4 dorsal rows of pigmentation of either side of spine. (D) Stage 34, brown pigmented feather tips appear along spine. (E) Stage 35, brown pigmentation identified on crown, anterior region of wing and along the thigh.
Fig 10.
Stages 36–39 (15–18 d) of the California valley quail’s embryological stages of development.
(A) Stage 36, primordia of scales on legs. (B) Stage 37, white feathers are present. (C) Stage 38, periderm beginning to peel off the beak. (D) Stage 39, scales begin to overlap.
Fig 11.
Stages 40–43 (19–23 d) of the California valley quail’s embryological stages of development.
(A) Stage 40, beak is more pointed than previous stage. (B) Stage 41, scales overlapping. (C) Stage 42, yolk-sac two-thirds to almost entirely inside body cavity. (D) Stage 43, newly hatched chick.
Fig 12.
Comparisons of developmental stages of California quail, northern bobwhite quail, Japanese quail, blue-breasted quail, and domestic chicken embryos.
(A) Stages for the first 5 days of development. (B) Stages for entire incubation period (≤23 days). (C) Comparison of stages and percentage of total incubation time. (D) Comparison of stages and of percentage of development.
Fig 13.
Time segments used for opening California valley quail eggs with observed key morphological structures for developing normal stages of development.