Postembryonic development of the cephalic region in Heterobranchus longifilis

Abstract

At hatching, Heterobranchus longifilis does not display any primordia of the cephalic skeleton. The latter appears 12 h post-hatching and develops in three stages up to day 16. The first stage (12 h to 2 days) involves almost exclusively the development of the chondrocranium. During the second period (days 3-8), dermal elements of the splanchnocranium appear. The final stage is marked by resorption of the cartilages, progressively replaced by ossifications (days 10-16). At their appearance the elements of the splanchnocranium are fused together, as are the first neurocranial elements. Later, the splanchnocranium splits up. By the time the yolk sac is completely resorbed, the buccal and pharyngeal jaws are present, the suspensoria and hyoid bars are partially developed, and the parasphenoid partially closes the hypophyseal fenestra. These structures delimit a buccal cavity that is probably functional, i.e. capable of participating in the intake of exogenous food. Next to continue its development is principally the splanchnocranium, completing the walls of the buccal cavity. Cartilage resorption parallels the appearance of endochondral ossifications (except for the trabecular bars). Braincase closure begins to accelerate once the buccal system is complete. 1997 The Fisheries Society of the British Isles No cephalic skeletal structure is visible. Day 1The first cartilaginous structures have appeared [ Fig. 1(a)]. They all belong to the splanchnocranium. These structures are: the hyosymplectic, the interhyal, the hyoid bar, the pars quadrata of the palato-quadrate, and Meckel's cartilage.    

Ontogeny of the chondrocranium in Corydoras aeneus (Gill, 1858) (Callichthyidae, Siluriformes)

“…The development of the branchial arches in C. aeneus differs from the situation described in siluriform fish up to this point. Generally, in siluriformes, chondrification in each arch starts with the ceratobranchials, followed by the hypobranchials and basibranchials, and eventually the epi-and pharyngobranchials (Srinivasachar, 1959;Adriaens and Verraes, 1997;Vandewalle et al, 1997). In C. aeneus, however, we found that all different elements arose simultaneously and continuously with each other.…”

“…However, several studies indicate that siluriform chondrocrania are generally limited in complexity at the time of hatching. Species like Chrysichthys auratus (Claroteidae) and Heterobranchus longifilis and Clarias gariepinus (Clariidae) show little to no chondrification at hatching while the chondrocranium in hatchlings from other species like Heteropneustes fossilis (Heteropneustidae) is only slightly developed (Srinivasachar, 1959;Adriaens and Verraes, 1997;Vandewalle et al, 1997Vandewalle et al, , 1999. Studies on species of the Loricarioidea superfamily, like Ancistrus cf.…”

“…At the same moment of this differentiation, the central copula detaches from all arches and splits into the typical anterior and posterior copula. Several authors have argued that the anterior part is the fusion of the first three basibranchials, with the posterior copula being a fused basibranchial IV and V (Srinivasachar, 1959;Adriaens and Verraes, 1997;Vandewalle et al, 1997). At the same time of the formation of both copulae, the hypobranchials of arches II and III separate as well.…”

Osteological development of wild-captured larvae and a juvenile Sebastes koreanus (Pisces, Scorpaenoidei) from the Yellow Sea

“…In most cases, early skeletal development occurs first in elements that are necessary for feeding and respiration and therefore affect the survival of young larvae (Vandewalle et al 1997;Wagemans and Vandewalle Fig. 3 Developmental sequences of the jaw bone, palate, and opercular series of Sebastes koreanus in preflexion larval to juvenile stages (lateral views).…”

“…However, the timing of the ossification of the hyomandibular is highly variable (Kim and Han 1991;Kim et al 1993;Kim et al 1997;Byun et al 2012). In most teleostei, the parasphenoid is the first element to ossify, except in some species in which the parasphenoid ossifies simultaneously with the frontals (Pagrus major; Matsuoka 1987) or the basioccipital (Heterobranchus longifilis; Vandewalle et al 1997), or is ossified after the ossification of the frontals (Scophthalmus maximus; Wagemans et al 1998). In S. koreanus, the first-ossified elements in the neurocranium (at 6.27 mm BL) are the (Fig.…”