The swimbladder plays an important role in buoyancy regulation but is typically reduced or even absent in benthic freshwater fishes that inhabit fast flowing water. Here, we document, for the first time, a remarkable example of swimbladder sexual dimorphism in the highly rheophilic South Asian torrent minnows (Psilorhynchus). The male swimbladder is not only much larger than that of the female (up to five times the diameter and up to 98 times the volume in some cases), but is also structurally more complex, with multiple internal septa dividing it into smaller chambers. Males also exhibit a strange organ of unknown function or homology in association with the swimbladder that is absent in females. Extreme sexual dimorphism of non-gonadal internal organs is rare among vertebrates and the swimbladder sexual dimorphisms that we describe for Psilorhynchus are unique among fishes.
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http://dx.doi.org/10.1098/rsbl.2014.0348 | DOI Listing |
J Insect Physiol
June 2024
Department of Biology, University of Haifa- Oranim, Kiryat Tivon, Israel.
J Exp Biol
August 2022
Cornell University, Department of Neurobiology and Behavior, Ithaca, NY 14853-7202, USA.
Acoustic behavior is widespread across vertebrates, including fishes. We report robust acoustic displays during aggressive interactions for a laboratory colony of Danionella dracula, a miniature and transparent species of teleost fish closely related to zebrafish (Danio rerio), which are hypothesized to be sonic based on the presence of a hypertrophied muscle associated with the male swim bladder. Males produce bursts of pulsatile sounds and a distinct postural display - extension of a hypertrophied lower jaw, a morphological trait not present in other Danionella species - during aggressive but not courtship interactions.
View Article and Find Full Text PDFPLoS One
July 2022
Dept. of Mechanical and Manufacturing Engineering, Miami University, Oxford, OH, United States of America.
Commun Biol
July 2021
Department of Functional Morphology and Biomechanics, Zoological Institute, Kiel University, Am Botanischen Garten 9, Kiel, Germany.
Here, the ultrastructure and development of the white patches on thorax and head of Bactrocera oleae are analysed using scanning electron microscopy, transmission electron microscopy, and fluorescence microscopy. Based on these analyses and measurements of patch reflectance spectra, we infer that white patches are due to modified air sacs under transparent cuticle. These air sacs show internal arborisations with beads in an empty space, constituting a three-dimensional photonic solid responsible for light scattering.
View Article and Find Full Text PDFZootaxa
May 2020
Grupo de Investigación en Peces Neotropicales, Fundación para la Investigación y el Desarrollo Sostenible FUNINDES, Cali, Colombia. Programa de Informática de la Biodiversidad, Instituto de Ciencias Naturales, Universidad Nacional de Colombia sede Bogotá. Cra. 30 no. 45-03, edificio 425.Bogotá D.C. Colombia..
Characidium chancoense new species, is described from the transandean upper Río Cauca drainage in Colombia. It can be distinguished from all congeners by its pigmentation pattern that consists of 7-12 vertical bars, most of which are cuneate-shaped with the vertex ending on or just below the lateral-line scale series, except for the last 1-4, which are dorsoventrally elongate rectangular bars that extend well below the lateral line. Characidium chancoense is sympatric with C.
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