The morphology of photophores in the garrick, cyclothone braueri (Family: Gonostomatidae): an ultrastructure study

Abstract

A contribution to the knowledge of the photophore structure of the mesopelagic fish Cyclothone braueri (Gonostomatidae) from the central Mediterranean Sea (Strait of Messina) is given by means of a structural and ultrastructural study, to better identify and classify the real anatomical structures costituing these luminous organs. The photocytes exhibit numerous secretory granules, of different electron density, embedded in an extremely developed rough endoplasmic reticulum. The lens appear to be composed of tightly contiguous polyhedral cells. The reflector is made up of cells rich in guanine crystals, embedded in an amorphous matrix and is surrounded by a layer of connective tissue containing melanocytes. Unlike the present knowledge, it is shown that the bioluminescence emitted from C. braueri light organs has glandular nature, with photophores similar to type α from Bassot classification. The phenomenon of adaptive convergence, documenting how the morphology and physiology of the light organs of teleosts is similar in different species despite their taxonomic distance, is confirmed also for C. braueri.

Influence of lunar phases, winds and seasonality on the stranding of mesopelagic fish in the Strait of Messina (Central Mediterranean Sea)

“…In the past, several scientists examined stranded ichthyofauna from the Strait, providing descriptions of this phenomenon (Berdar, Cavaliere, Cavallaro, Giuffrè, & Potoschi, 1983;Berdar, Cavallaro, Giuffrè, & Potoschi, 1977;Genovese et al, 1971;Guglielmo et al, 1995;Longo, 1882;Mazzarelli, 1909;Scotto di Carlo et al, 1982;Spalletta et al, 1995). Recently, other authors extended the knowledge of the biology and ecology of mesopelagic fish (Battaglia, Malara, et al, 2015;Battaglia et al, 2010Battaglia et al, , 2016Cavallaro, Mammola, & Verdiglione, 2004;Cavallaro et al, 2015;Romeo, Pedà, Fossi, Andaloro, & Battaglia, 2016) as well as of rare and poorly known deep-sea species (Battaglia, Ammendolia, Esposito, Romeo, & Andaloro, 2014;Battaglia, Ammendolia, Romeo, & Andaloro, 2012;Battaglia, Ammendolia, Romeo, Esposito, & Andaloro, 2013;Battaglia, Canese, et al, 2015;Cavallaro, Ammendolia, Andaloro, & Battaglia, 2017). However, to date, the stranding of mesopelagic fauna has never been quantified and analysed in order to test the influence of environmental parameters upon this phenomenon.…”

New data on morphology and ultrastructure of skin photophores in the deep‐sea squid Histioteuthis bonnellii (Férussac, 1834), Cephalopoda: Histioteuthidae

“…2B) may be in a status of cytoplasmic rearrangement different from the active synthesis, as also observed by Cavallaro et al (2004Cavallaro et al ( , 2014 in the photocytes of some deep-water fish species. Specialized membranes, with the shape of loops or skeins were observed in the cytoplasm, concentrated in a marginal area of the cell, close to the Golgi apparatus; they likely originate from membranes of endoplasmic reticulum, have an electron dense aspect and seem to be involved in a process of progressive condensation.…”

“…According to Cavallaro et al (2014), the photophores were fixed in Bouin's liquid for 12 h. After dehydration in an increasing alcohol series (70%, 80%, 95%, 100% alcohol), the samples were embedded in paraffin wax. Thick sections (4 mm) were placed on glass slides and put in an oven for 24 h. The sections, deparaffined in xylene and rehydrated in a decreasing alcohol series (100%, 95%, 80%, 70% alcohol to distilled water), were submitted to the standard techniques of staining using haematoxylin-eosin and Masson's trichrome stain (Beccari and Mazzi 1966).…”

The first report of luminescent liver tissue in fishes: Evolution and structure of bioluminescent organs in the deep-sea naked barracudinas (Aulopiformes: Lestidiidae)

“…D and C). Other dermal light organs in the distantly related stomiiform, myctophiform, and batrachoidiform fishes also have photogenic cells with granular inclusions that likely fuse with vacuoles or release their content into ducts or an extracellular space as a component of light production (Nicol, ; Copeland, ; Herring and Cope, ; Krönström and Mallefet, ; Cavallaro et al, ). The sinuses found in both luminescent organs are suggestive that the light –production mechanism in both organs may involve extracellular secretion.…”