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International Journal of Marine Science 2014, Vol.4, No.33
http://ijms.biopublisher.ca
3
haemal arches are fused from the 11
th
vertebra and
prolonged by a haemal spine. This latter spine is at its
maximum length at V12 and decreased in length
posteriorly. The anterior surface of the haemal arch is
characterized with presence of wide trough-like cavity
which getting narrower posteriorly. Haemal spine
appears at V11. There is no intraspecific variation in
the shape of vertebrae is noticed.
The centrum is made of two halves of sphere joined
by their curved sides (Amphicoelic vertebrae), whose
chordal cavities connected by a thin hole.
There is pair
of anterior processes and a pair of posterior processes
protrudes from the dorsal aspects of each centrum.
The anterior and posterior processes are close to each
other and lie 1–2 mm from one another with external
ligament bounding them together. Neural spines and
arches project from the dorsal aspect of each vertebral
centrum.
The first 3 vertebral centra differ qualitatively from
the remaining abdominal vertebrae. The adjacent
centra are joined together through the dorsal anterior
processes of one vertebra which overlap to a greater
degree with the dorsal posterior processes of the other
vertebra, e.g. the dorsal anterior processes of centrum
of the 2
nd
vertebra overlap substantially with the
proximal portion of the dorsal posterior processes of
the first centrum near the base of the neural spine.
This overlap of processes is present for the first 4
vertebra. In addition, these four vertebrae have
parapophysis are dorsally located relative to the
parapophysis found on the abdominal rib-bearing
vertebrae and located at the base of the neural spine.
These ribs do not extend down to surround the viscera.
Vertebrae 2–10 have a typical abdominal vertebral
morphology with well-developed anterior and
posterior dorsal processes but gradually become less
developed posteriorly to V11. In addition, the two
portions of each centrum, dorsal and ventral, are
connected to each other by significant of bony
material. In having both haemal arches and short
ventrally located parapophyseal projections that
articulate with ribs that extend ventrally around the
viscera, the vertebrae V2-V5 are considered to have a
transitional form. Finally, vertebrae 11–23 have a
typical caudal vertebral morphology with reduced
dorsal processes relative to the first 3 vertebrae, an
absence of ribs and parapophyseal articulations, and
presence of haemal arches and spines. In the
transitional and caudal regions, a prominent lateral
ridge is clear along the midline of each centrum.
The vertebral column of
L. equulus
showed characteristic
regionalization (Table 1). Firstly, the anterior postcranial
Table 1 Average values (M) (mm) of vertebral length (VL), vertebral height (VH), vertebral width (VW) and vertebral central width
(VCW) of the vertebral column of
Leiognathus equulus
(SD = standard deviation)
No
LV
VH
VCW
VW
Ordinal no. of vertebrae
M ±SD
M ±SD
M ±SD
M ±SD
1
19.82±1.41
24.40±1.13
13.43±1.95
2.34±1.94
2
21.87±1.23
26.13±1.41
16.07±1.37
4.20±1.86
3
23.87±1.42
25.48±1.33
16.84±1.81
4.76±1.87
4
26.83±1.76
25.05±1.25
17.55±1.80
3.06±1.45
5
29.11±1.89
23.74±1.39
16.91±1.49
3.63±1.22
6
30.35±1.48
23.89±1.17
18.24±1.28
3.89±1.32
7
30.28±1.56
23.17±1.56
17.48±1.18
3.97±1.32
8
31.05±1.43
23.33±1.49
17.40±1.31
3.80±1.63
9
31.52±1.22
23.19±1.40
17.21±1.30
3.84±1.43
10
31.32±1.11
23.92±1.90
19.11±1.68
4.04±1.54
11
32.08±1.22
24.30±1.29
19.25±1.52
3.96±1.43
12
32.53±1.43
24.14±1.75
19.36±1.34
3.86±1.23
13
32.93±1.91
23.86±1.98
19.72±1.17
4.23±1.33
14
32.76±1.76
23.79±1.73
18.80±1.69
4.46±1.76
15
33.73±1.17
23.85±1.63
18.51±1.83
4.44±1.45
16
33.85±1.56
24.93±1.27
17.69±1.61
4.36±1.34
17
34.25±1.70
24.47±1.82
16.53±1.63
4.25±1.54
18
34.81±1.44
24.04±1.83
15.46±1.47
4.07±1.34
19
34.17±1.51
22.67±1.71
15.09±1.52
3.98±1.44
20
29.60±1.62
21.93±1.54
14.17±1.12
4.30±1.24
21
23.43±1.59
20.47±1.37
15.17±1.20
4.12±1.23
22
19.28±1.88
19.13±1.51
14.43±1.55
3.90±1.43
23
18.54±1.43
17.39±1.83
11.47±1.22
3.84±1.67