A first record of <i>Isistius plutodus</i> in the north‐eastern Atlantic

Zidowitz, H.; Fock, Heino O.; Pusch, Christian; Westernhagen, Hein von

doi:10.1111/j.0022-1112.2004.00382.x

Cited by 8 publications

(4 citation statements)

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“…Among the 10 currently described species encompassed by this family are some of the rarest sharks, known by extremely few specimens (Mollisquama parini and Isistius labialis -each known by one specimen; Euprotomicroides zantedeschia -known by two specimens; Heteroscymnoides marleyi -known by six specimens; and Isistius plutodus -known by 10 specimens), and others are localised or relatively inaccessible, which probably explains why most remain poorly known to science (Compagno et al, 2004;Zidowitz et al, 2004). At least nine of these sharks are endowed with thousands of tiny photogenic organs called photophores that allow them to produce a visible light as a result of a chemical reaction (Hubbs et al, 1967;Seigel, 1978;Reif, 1985;Stehmann and Kreft, 1988;Compagno et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Control of luminescence from pygmy shark (Squaliolus aliae) photophores

Claes

Mallefet

2012

Journal of Experimental Biology

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SUMMARYThe smalleye pygmy shark (Squaliolus aliae) is a dwarf pelagic shark from the Dalatiidae family that harbours thousands of tiny photophores. In this work, we studied the organisation and physiological control of these photogenic organs. Results show that they are mainly situated on the ventral side of the shark, forming a homogeneous ventral photogenic area that appears well suited for counterillumination, a well-known camouflage technique of pelagic organisms. Isolated ventral skin patches containing photophores did not respond to classical neurotransmitters and nitric oxide but produced light after melatonin (MT) application. Prolactin and a-melanocyte-stimulating hormone inhibited this hormonally induced luminescence as well as the spontaneous luminescence from the photogenic tissue. The action of MT seems to be mediated by binding to the MT 2 receptor subtype, as the MT 2 receptor agonist 4P-PDOT inhibited the luminescence induced by this hormone. Binding to this receptor probably decreases the intracellular cAMP concentration because forskolin inhibited spontaneous and MT-induced luminescence. In addition, a GABA inhibitory tonus seems to be present in the photogenic tissue as well, as GABA inhibited MT-induced luminescence and the application of bicuculline provoked luminescence from S. aliae photophores. Similarly to what has been found in Etmopteridae, the other luminous shark family, the main target of the luminescence control appears to be the melanophores covering the photocytes. Results suggest that bioluminescence first appeared in Dalatiidae when they adopted a pelagic style at the Cretaceous/Tertiary boundary, and was modified by Etmopteridae when they started to colonize deep-water niches and rely on this light for intraspecific behaviours.

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Section: Introductionmentioning

confidence: 99%

Control of luminescence from pygmy shark (Squaliolus aliae) photophores

Claes

Mallefet

2012

Journal of Experimental Biology

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“…(2004): 169 (predation) [ 190 ]; Soto & Mincarone (2004): 7, 70 (listed) [ 194 ]; Zidowitz et al . (2004): 1430–1433 (notheast Atlantic) [ 345 ]; Compagno et al . (2005a): 128, 129, pl.…”

Section: Resultsmentioning

confidence: 99%

Comparative morphology and systematics of the cookiecutter sharks, genus Isistius Gill (1864) (Chondrichthyes: Squaliformes: Dalatiidae)

Petean

Carvalho

2018

PLoS ONE

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The dalatiid genus Isistius Gill (1864) has three valid species currently recognized in the literature: Isistius brasiliensis Quoy & Gaimard (1824), I. plutodus Garrick & Springer (1964), and I. labialis Meng, Zhu & Li (1985). The most common species, I. brasiliensis, has a wide geographic distribution and is found in subtemperate and tropical seas circumglobally. A comparative analysis of specimens from different localities throughout its range, however, had never been undertaken. In the present paper, the morphological variation of this species along its entire distribution has been thoroughly analyzed, corroborating that it represents a single widespread species and that I. labialis is its junior synonym. The other congeneric species, I. plutodus, is known from only a few specimens and is also distributed worldwide. A detailed comparative analysis of available material of I. plutodus was conducted verifying its validity as a single widespread species. The present study analyzed in detail the external morphology (coloration, dentition, dermal denticles), internal morphology (skeleton, musculature), lateral-line canals, and morphometric and meristic characters of species of Isistius in order to better define the genus and its included valid species.

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“…Isistius brasiliensis inhabits water depths from 3700 m to the surface and is known to make daily vertical migrations through the water column, spending time deep in the water column during the day and traveling to the surface at night (Kiraly et al, 2003;Compagno et al, 2005). Isistius plutodus, on the other hand, typically occurs in a narrower depth range between 60 and 200 m (Zidowitz et al, 2004;Compagno et al, 2005). Despite this difference in depth preference, both spe- cies share a unique feeding strategy that has earned them the common name, the Cookiecutter Sharks, and the status as the only parasitic sharks.…”

Section: Post-processingmentioning

confidence: 99%

The first documented fossil records of Isistius and Squatina (Chondrichthyes) from Florida, with an overview of the associated vertebrate fauna

Perez,

Marks

2017

FLMNH

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In October 2016, an email inquiring about the geologic age of a creek in Sarasota County led to the serendipitous ‘discovery’ of fossil teeth of the sharks Isistius triangulus and Squatina sp. in Florida. Up to that point, no fossils of Isistius or Squatina from Florida were present in the vertebrate paleontology collections at the Florida Museum of Natural History, nor had they been listed in any scientific publication. However, public inquiries revealed that the presence of both genera in the Florida fossil record has been known among the amateur paleontology community for well over a decade. Once co-author Marks was made aware that the Isistius teeth represented something novel, more rigorous collecting was conducted to procure more specimens. A total of 94.5 kg of matrix from four gravel deposits within the creek, informally known as Cookiecutter Creek, were screenwashed and picked to produce 186 whole or partial lower teeth of Isistius triangulus and four teeth belonging to Squatina. In addition, a diverse vertebrate fauna was recovered that ranged from Pliocene to Pleistocene in age. Screenwashing of 7.5 kg of matrix from the in situ Pleistocene Caloosahatchee Formation revealed no specimens of Isistius or Squatina, which implies their actual source is the underlying Pliocene Tamiami Formation. The unprecedented occurrence of Isistius triangulus, with such a high density in Cookiecutter Creek relative to other sites in Florida, may indicate that Cookiecutter Creek preserves a unique deep-water facies within the Tamiami Formation. The associated vertebrate fauna includes taxa from marine, brackish, freshwater, and fully terrestrial paleoenvironments; providing evidence of local sea-level fluctuations during the Pliocene to Pleistocene. The temporally mixed accumulation in these gravel deposits inhibits a more accurate reconstruction of these sea-level fluctuations.

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A first record of Isistius plutodus in the north‐eastern Atlantic

Cited by 8 publications

References 3 publications

Control of luminescence from pygmy shark (Squaliolus aliae) photophores

Control of luminescence from pygmy shark (Squaliolus aliae) photophores

Comparative morphology and systematics of the cookiecutter sharks, genus Isistius Gill (1864) (Chondrichthyes: Squaliformes: Dalatiidae)

The first documented fossil records of Isistius and Squatina (Chondrichthyes) from Florida, with an overview of the associated vertebrate fauna

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