a slender, horny, flexible, unsegmented fibril which strengthens the embryonic fin fold and which may persist in the outer edge of the adult fin membrane or in the adipose fin. It develops intercellularly rather than cellularly. Persists in fins of Elasmobranchii, Holocephali, and sometimes in Teleostomi distal to the lepidotrichia that replace them. Actinotrichia are translucent, exhibit birefringence (double refraction) and are composed of a scleroprotein called elastoidine. They may be homologous with ceratotrichs found in cartilaginous fishes because of their horny or keratinous nature
Dictionary of ichthyology. 2009.
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actinotrich — a, us Gk aktinos, ray; thrix, hair. With hairs radiating from the orifice of the leaf sheath … Etymological dictionary of grasses
actinotrich — ac·tin·o·trich … English syllables
actinotrich — noun see actinotrichium … Useful english dictionary
actinotrichium — (plural actinotrichia) actinotrich … Dictionary of ichthyology
dermotrichium — (plural dermotrichia)) the fin ray, of 4 types: ceratotrich (in cartilaginous fishes), actinotrich (in cartilaginous and bony fishes), lepidotrichs (only in bony fishes) and camptotrichs (in Dipnoi and Crossopterygi). Spiny rays in Actinopterygii … Dictionary of ichthyology