caa a22 4500 477116051 CHVBK 20180405111622.0 cr unu---uuuuu 170330e19960301xx s 000 0 eng 10.1007/BF00003092 doi (NATIONALLICENCE)springer-10.1007/BF00003092 Convergence of a cryptic saddle pattern in benthic freshwater fishes [Elektronische Daten] [Jonathan Armbruster, Lawrence Page] Synopsis: Many North American stream fishes have a similar color pattern of four dark saddles against a light background. An interesting feature of the pattern, in addition to its widespread taxonomic distribution, is its consistent configuration. The interval between the first and second saddle is usually the largest, and the last (third) interval is the smallest. All saddled North American freshwater fishes live on uneven, rocky substrates, and nearly all live in flowing water. It is hypothesized that these fishes achieve crypsis through disruptive coloration; the light spaces between the saddles mimic rocks and the dark saddles appear as shadows or gaps between rocks. Saddles are spaced unevenly because rocks in streams are a mixture of sizes; a fish that mimics a series of rocks of similar sizes is more conspicuous than one that mimics rocks of different sizes. The placement of saddles was measured on five North American species. In four of five North American species measured (a sculpin and three darters), the longest spaces are towards the head where the body is also the widest, this is thought to enhance crypsis because pieces of gravel tend to be round or square. In the madtom, the saddle pattern tends more towards even spacing. The madtom may not rely on camouflage to the same extent as other species examined because of decreased predation pressure associated with being nocturnal and possessing sharp spines and venom glands. Kluwer Academic Publishers, 1996 Camouflage nationallicence Disruptive coloration nationallicence Etheostoma blennius nationallicence E. variatum nationallicence Percina uranidea nationallicence Noturus flavater nationallicence Cottus carolinae nationallicence Armbruster Jonathan Illinois Natural History Survey, 61820, Champaign, IL., U.S.A. aut Page Lawrence Illinois Natural History Survey, 61820, Champaign, IL., U.S.A. aut Environmental Biology of Fishes Kluwer Academic Publishers 45/3(1996-03-01), 249-257 0378-1909 45:3<249 1996 45 10641 https://doi.org/10.1007/BF00003092 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00003092 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Armbruster Jonathan Illinois Natural History Survey, 61820, Champaign, IL., U.S.A aut NATIONALLICENCE 700 1- Page Lawrence Illinois Natural History Survey, 61820, Champaign, IL., U.S.A aut NATIONALLICENCE 773 0- Environmental Biology of Fishes Kluwer Academic Publishers 45/3(1996-03-01), 249-257 0378-1909 45:3<249 1996 45 10641 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer