Dear Eman,

About what catfishes are you talking? Some catfishes has two cranial fontanelles, others have only one, others have none.

Regards,

Gloria Arratia

Dear Gloria, thank you for your response, I would like to understand the function of the catfishes fontanelles in general, and the Nile-catfishes in particular, I have been studied four families Bagridae (B. bajad); Clariidae (C. garpineus); Malapteruridae (M. electricus) and Mochokidae (S. schall), J. Morphol. Sci., 2014, vol. 31, no. 3, p. 162-170, http://dx.doi.org/10.4322/jms.059913. The text below,  for you, repeated my question as described in the discussion section: 

Our results revealed that, the anterior fontanelle was

present in the four studied species; while the posterior one

was absent in M.electricusand S.schall. Adriaens and Verraes

(1998) reported that, the posterior fontanelle also known as

the parietal foramen, exposed pineal gland to direct sun light.

In S.schall a third paired and small fontanelle was present, the

lateral fontanelle. It is located between sphenotic, pterotic

and posttemporo-supracliethrum bones, in this position it

resembled the sphenoidal fontanelles of mammales, which

located between the sphenoid, parietal, temporal and frontal

bones (HOLLINSHEAD and ROSSE, 1985) in man and

(SCHALLER, 2011) in dog. The question raised here is

why catfishes has such fontanelles, Artenerr, Pekney and

Gergelova (2003) reported that, in man the fontanelles

provide two important functions, First, they provide space

between the bones and make the newly born skull flexible

during the childbirth. Second, they support the fast growth

by their expansions. We suggest that, the fontanelles make

the roof of the skull flexible especially during expansion

phase of suction feeding, as their edges may adduct then

raising the floor of the neurocranium to increase the width

of the oropharyngeal cavity.

Thank you very much, I am looking forward to hear from you.

Dear Eman,

Thank you very much for your explanation. As I see the situation, but I can be wrong, you want to understand the function of the fontanelles in catfishes, but as I wrote you in my first mail, you can find three conditions in catfishes (as well as in other teleosts): two, one, and no fontanelles in the median region of the skull roof. Thus, cranial fontanelles are not limited only to catfishes. However, if we want to limit the discussion only about catfishes, then two hypotheses have being proposed, the one from Adriaens & Verraes (1998) for the posterior fontanelle and your hypothesis that these spaces are functionally related to feeding mechanism. But a problem remain: how do we explain the lack of these fontanelles in some catfishes? I think that you have a very interesting question and I suggest testing these hypotheses experimentally for both situations: presence and absences of fontanelles.

With my best wishes,

Gloria

Thank you very much, I agree with you.