Drastic shift in the number of lateral line scales in the common roach Rutilus rutilus as a result of heterochronies: experimental data
2010
Levin, B.A.
The ontogeny of the larvae and juveniles of the common roach, Rutilus rutilus, was accelerated and retarded via treatment with the thyroid hormone triiodothyronine (T₃), and thiourea. This treatment resulted in differential timing of scale formation. Development of squamation was earlier in accelerated fish but delayed in retarded fish compared with a control fish. A drastic shift in the number of lateral line scales (LL) resulted. Instead of a typical range of LL, retarded fish had an increased LL compared to the control as well as for the species as a whole, 47-71 vs 41-48, while accelerated fish had reduced LL: 38-44 vs 41-48. The mechanism of this drastic change in LL was related to developmental change in the timing of events, leading to changes in size and shape (heterochrony). The number of scales obtained experimentally was correlated to the body length at which scales first appeared.
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