The initial anatomical regions with osteological development were mandible, pectoral fin (cleithrum), ceratobranchial and gill arches
at 3 DPH in crimson snapper.
The same result was obtained when comparing segments at the gill arch
level (Table 4).
In the branchial region these fishes all have paired symmetrical gill arch
bones that support pharyngeal tooth plates, gill rakers and gill filaments (e.g., studied by Frame et al.
The lower jaw, teeth, and Meckel's cartilage develop when cells of the cranial neural crest (CNC), which give rise to the dorsal neural tube, migrate into the gill arches
The semilunar base of each gill raker is attached to the mucous membrane of the gill arch
. The longest gill takers occur near the center of the arc and are about 9 cm long in the LACM specimen.
There was also staining in the endothelium of vessels in the gill arches
of the DR fish.
The two structures of primary importance in the transition from agnathan (jawless) fish to gnathostomes were the mandibular arch (gill arch
2) and the hyoid arch (gill arch
a) Trichodinids in a fresh-mounted smear from the gill arches
, b) differential interference contrast microscope, c) an adhesive disc of Trichodina in silver nitrate impregnation, d) T.
Each gill arch
is divided into a long ceratobranchial part and short epibranchial part.
The degeneration and necrosis were also observed within the gill filaments along with a dilation of the gill arch
in which it expands as compared to its normal condition as shown in Figure 1C.
These indexes are calculated as follows: H'= - Pi [s.summation over (i=1)] [log.sub.2] Pi and E = H'/[log.sub.2]S where for a given gill arch
, Pi represents the relative abundance of parasite species i and S corresponds to the specific richness.