Cleared and stained branchial basket from WT, TH−, and TH+
zebrafish. (A, C, and E) Dorsal view of
the branchial basket. Note the more prominent cartilaginous junctions in
TH−. (B, D, and F) Lateral and
medial view of the pharyngeal jaws. Bold arrows indicate the supporting struts
of the pharyngeal jaws. Black boxes surround the teeth. (G) WT
showed between 7 and 12 teeth on each pharyngeal jaw (average = 9.6, N = 10
fish), TH− showed between 9 and 17 (average = 12.95, N = 10 fish) and TH+
showed between 7 and 10 (average = 8.1, N = 8 fish). The presence of TH inhibits
pharyngeal teeth, as TH− jaws had significantly more teeth (two tailed t
test P = 1.4e-05) and TH+ had significantly fewer teeth
(P = 0.0079) than WT jaws. Further, teeth were more
robustly ankylosed to the ceratobranchial in TH+. Abbreviations: bb,
basibranchial; cb, ceratobranchial; ch, ceratohyal; eb, epibranchial; eh,
epihyal; hhd, hypohyal dorsal; hhv, hypohyal ventral; pb, pharyngobranchial.
Bones within a series are labeled with the corresponding numbers (e.g., pb 1, pb
2 + 3).