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Novel structure in sciaenid fish skulls indicates continuous production of the cephalic neuromast cupula

View Article: PubMed Central - PubMed

ABSTRACT

The presence of a conspicuous and frequent but never-described structure in the skull cavities of sciaenid fish was noted during population studies in an urbanized bay. The ultrastructure closely resembles the cupula of neuromasts, an organ associated with the perception of the environment in teleost fish. The bodies were recorded detached in both preserved and freshly sampled individuals and without associated cilia. Prominent characteristics are acellularity, the elliptic-conic shape composed of stack-like protein lamellas, and a mesh-like appearance in cross section. These acellular lamellar cephalic bodies (ALCBs) were more abundant in larger individuals and showed temporal peaks of abundance independently of the fish size. The conic and lamellar features suggest that the deposition of protein layers follows fish growth, and the bimodality of the size of these structures in individuals indicates temporal peaks of production. These results indicate that these ALCBs are a consequence of the accretion of the cupula of neuromasts at a faster rate than they degrade. Given the novelty of this structure and the increasing records of diseases of marine organisms worldwide, an important question is whether these bodies occur subsequently to some environmental change and whether their accumulation in the skull cavities has consequences to fish health.

No MeSH data available.


ALCB abundance over time.Temporal distribution of the abundance of Acellular Lamellar Cephalic Bodies for different fish sizes–variable number. Mean and standard error of the number of ALCBs. For each of the ten months (August 2003 through October 2004), 20 individuals of each size class (bottom to top: small–5 to 8 cm, medium – >8 to 11 cm, and large – >11 to 14 cm) of Stellifer rastrifer, sampled in Caraguatatuba Bay, were examined. Letters in brackets denote significant differences among months, discriminated by the Tukey test.
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f6: ALCB abundance over time.Temporal distribution of the abundance of Acellular Lamellar Cephalic Bodies for different fish sizes–variable number. Mean and standard error of the number of ALCBs. For each of the ten months (August 2003 through October 2004), 20 individuals of each size class (bottom to top: small–5 to 8 cm, medium – >8 to 11 cm, and large – >11 to 14 cm) of Stellifer rastrifer, sampled in Caraguatatuba Bay, were examined. Letters in brackets denote significant differences among months, discriminated by the Tukey test.

Mentions: Quantification analysis showed a significant positive relationship between the number of ALCBs and the total length of individual fish (Fig. 5), and that, despite fish size, the fish caught in some months had significantly higher amounts (Fig. 6), as denoted by the significant relationship of abundance with both size and date (F10,500 = 34.88, p < 0.01, Adj.r2 = 0.40), and the lack of a significant interaction of the two (AICs = 3665 and 3652). The size relationship indicates that ALCBs are produced continuously over time, in contrast to the number of neuromasts, which is species-specific and does not increase with increased fish size. In line with the suggested hypothesis, this indicates that the fish does not decompose/release ALCBs at the same rate at which they are produced. The month-to-month variation sheds some light on an important question regarding ALCBs. They may have simply been overlooked so far, or, their occurrence or abundance may have some environmental significance. An important further step is to compare their occurrence and abundance in fish in different areas. The temporal variation does indicate that the production rate of ALCBs is influenced by the environment.


Novel structure in sciaenid fish skulls indicates continuous production of the cephalic neuromast cupula
ALCB abundance over time.Temporal distribution of the abundance of Acellular Lamellar Cephalic Bodies for different fish sizes–variable number. Mean and standard error of the number of ALCBs. For each of the ten months (August 2003 through October 2004), 20 individuals of each size class (bottom to top: small–5 to 8 cm, medium – >8 to 11 cm, and large – >11 to 14 cm) of Stellifer rastrifer, sampled in Caraguatatuba Bay, were examined. Letters in brackets denote significant differences among months, discriminated by the Tukey test.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5120346&req=5

f6: ALCB abundance over time.Temporal distribution of the abundance of Acellular Lamellar Cephalic Bodies for different fish sizes–variable number. Mean and standard error of the number of ALCBs. For each of the ten months (August 2003 through October 2004), 20 individuals of each size class (bottom to top: small–5 to 8 cm, medium – >8 to 11 cm, and large – >11 to 14 cm) of Stellifer rastrifer, sampled in Caraguatatuba Bay, were examined. Letters in brackets denote significant differences among months, discriminated by the Tukey test.
Mentions: Quantification analysis showed a significant positive relationship between the number of ALCBs and the total length of individual fish (Fig. 5), and that, despite fish size, the fish caught in some months had significantly higher amounts (Fig. 6), as denoted by the significant relationship of abundance with both size and date (F10,500 = 34.88, p < 0.01, Adj.r2 = 0.40), and the lack of a significant interaction of the two (AICs = 3665 and 3652). The size relationship indicates that ALCBs are produced continuously over time, in contrast to the number of neuromasts, which is species-specific and does not increase with increased fish size. In line with the suggested hypothesis, this indicates that the fish does not decompose/release ALCBs at the same rate at which they are produced. The month-to-month variation sheds some light on an important question regarding ALCBs. They may have simply been overlooked so far, or, their occurrence or abundance may have some environmental significance. An important further step is to compare their occurrence and abundance in fish in different areas. The temporal variation does indicate that the production rate of ALCBs is influenced by the environment.

View Article: PubMed Central - PubMed

ABSTRACT

The presence of a conspicuous and frequent but never-described structure in the skull cavities of sciaenid fish was noted during population studies in an urbanized bay. The ultrastructure closely resembles the cupula of neuromasts, an organ associated with the perception of the environment in teleost fish. The bodies were recorded detached in both preserved and freshly sampled individuals and without associated cilia. Prominent characteristics are acellularity, the elliptic-conic shape composed of stack-like protein lamellas, and a mesh-like appearance in cross section. These acellular lamellar cephalic bodies (ALCBs) were more abundant in larger individuals and showed temporal peaks of abundance independently of the fish size. The conic and lamellar features suggest that the deposition of protein layers follows fish growth, and the bimodality of the size of these structures in individuals indicates temporal peaks of production. These results indicate that these ALCBs are a consequence of the accretion of the cupula of neuromasts at a faster rate than they degrade. Given the novelty of this structure and the increasing records of diseases of marine organisms worldwide, an important question is whether these bodies occur subsequently to some environmental change and whether their accumulation in the skull cavities has consequences to fish health.

No MeSH data available.