Royal knifefish generate powerful suction feeding through large neurocranial elevation and high epaxial muscle power

Li, Ellen Y, Kaczmarek, Elska B, Olsen, Aaron M, Brainerd, Elizabeth L and Camp, Ariel L ORCID: 0000-0002-3355-4312 (2022) Royal knifefish generate powerful suction feeding through large neurocranial elevation and high epaxial muscle power JOURNAL OF EXPERIMENTAL BIOLOGY, 225 (11). jeb244294-. ISSN 0022-0949, 1477-9145

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Abstract

Suction feeding in ray-finned fishes involves powerful buccal cavity expansion to accelerate water and food into the mouth. Previous XROMM studies in largemouth bass (Micropterus salmoides), bluegill sunfish (Lepomis macrochirus) and channel catfish (Ictalurus punctatus) have shown that more than 90% of suction power in high performance strikes comes from the axial musculature. Thus, the shape of the axial muscles and skeleton may affect suction feeding mechanics. Royal knifefish (Chitala blanci) have an unusual postcranial morphology, with a ventrally flexed vertebral column and relatively large mass of epaxial muscle. Based on their body shape, we hypothesized that royal knifefish would generate high power strikes by utilizing large neurocranial elevation, vertebral column extension and epaxial shortening. As predicted, C. blanci generated high suction expansion power compared with the other three species studied to date (up to 160 W), which was achieved by increasing both the rate of volume change and the intraoral subambient pressure. The large epaxial muscle (25% of body mass) shortened at high velocities to produce large neurocranial elevation and vertebral extension (up to 41 deg, combined), as well as high muscle mass-specific power (up to 800 W kg⁻¹). For the highest power strikes, axial muscles generated 95% of the power, and 64% of the axial muscle mass consisted of the epaxial muscles. The epaxial-dominated suction expansion of royal knifefish supports our hypothesis that postcranial morphology may be a strong predictor of suction feeding biomechanics.

Item Type:	Article
Uncontrolled Keywords:	XROMM, Fluoromicrometry, Muscle strain, Buccal pressure, Body shape, Buccal volume
Divisions:	Faculty of Health & Life Sciences Faculty of Health & Life Sciences > Inst. Life Courses & Medical Sciences
Depositing User:	Symplectic Admin
Date Deposited:	18 Nov 2022 14:09
Last Modified:	16 Jun 2026 12:10
DOI:	10.1242/jeb.244294
Open Access URL:	https://www.biorxiv.org/content/biorxiv/early/2022...
Related Websites:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3166278
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