Transcript Identification of Larval Fish Family: Monacanthidae Presented by: Edwison Setya F.

Identification of Larval Fish
Family: Monacanthidae
Presented by:
Edwison Setya F.
*) Presented in Advanced Regional Workshop on Larval Fish Identification and Fish Early Life
History Science, 26 May – 15 June 2008 in Seafdec TD, Samut Prakan, Thailand.
Review of Morphological Features
Morph 01
Morph 02
Body shape
Deep to elongate, becoming
angular with growth.
Compressed.
Deep, becoming deeper with
growth, but remaining rounded.
Body depth
preflex. 17-59
30-64
proportion of SL
postfex 12-58
56-63
Myomeres
17-31
20-22
Preopercular tuft
Small to large
Absent
Tail pigment in
preflexion
Present
Absent
Pelvis
Barbed and prominent to not
externally visible
Not externally visible
Dorsal fin spine
Forms before soft rays and
flexion (2.1 mm), weakly to
strongly armed
Forms after soft rays and flexion
(3-5 mm), unarmed to at least 6
mm.
Dorsal fin soft rays Moderate to many (26-51)
Few to moderate (22-30)
Review of Morphological Features (contd.)
Morph 01
Morph 02
Size at flexion
3.4-6.5 mm
2.8-3.5 mm
Notochord tip
Long and persist in postflexion Doesn't persist in postflexion
larvae
larvae
Identified taxa
included
Aluterus, Amanses,
Cantherhines, Monacanthus,
Oxymonacanthus,
Pseudalutarius,
Stephanolepis, Thamnaconus
Brachaluteres, Paraluteres,
Rudarius.
Review of Morphological Features (contd.)
Table of Meristic Character
Genus
D
A
P1
C
Vert
Acreichthys
II + 26-30
25-29
10-12
12 7+13
Aluterus
II + 43-51
46-54
13-15
12 7+(14-16)
Amanses
II + 26-29
22-25
13
12 7+12
Anacanthus
I + 47-52
56-62
8-10
12 7+(22-24)
Brachaluteres
II + 23-30
20-27
10-12
12 7+13
Cantherhines
II + 32-39
28-35
11-15
12 7+12
Cantheschenia
II + 34-41
32-36
10-14
12 7+12
Chaetodermis
II + 25-27
23-25
11-13
12 7+13
Colurodontis
II + 27-32
26-31
10-12
12 7+12
Eubalichthys
II + 32-39
33-37
12-14
12 7+12
Lalmohania
II + 25-27
25-28
10-11
12 7+12
Monacanthus
II + 28-34
27-34
11-14
12 7+12
Oxymonacanthus
II + 26-35
23-32
10-12
12 8+(17-18)
Paraluteres
II + 25-28
24
11-12
12 7+(13-14)
Paramonacanthus
II + 24-33
24-34
10-13
12 (6-7)+(12-13)
Review of Morphological Features (contd.)
Table of Meristic Character
Genus
D
A
P1
C
Vert
Pervagor
II + 29-39
25-36
10-14
12 7+12
Pseudalutarius
II + 43-50
41-46
11-12
12 8+(18-21)
Pseudomonacanthus
II + 28-35
27-34
10-13
12 7+12
Rudarius
II + 22-28
20-28
11-12
12 7+(12-13)
Stephanolepsis
II + 28-35
29-34
10-14
12 7+12
Thamnaconus
II + 31-39
30-37
12-16
12 7+12
Information of Sampling
This sample is taken from Southern of South
China Sea (SCS). Especially in Western
Kalimantan waters, around Natuna islands.
Taken on mid year 2005, in the collaborative
research between Seafdec and Indonesian
officers.
Sampling gear was bongo net of MV Seafdec 2.
Information of Sampling (Contd.)
Sampling track.
Figure
BL: 2.91 mm
BL: 3.48 mm
BL: 3.47 mm
BL: 3.54 mm
Figure
BL: 4.02 mm
BL: 3.82 mm
BL: 4.03 mm
BL: 4.45 mm
Detail of Illustrated Specimen
TL: 10.95 mm
TL
BD
ED
SnL
PAL
Stage
: 10.92 mm
: 4.0 mm
: 1.2 mm
: 8.5 mm
: 5.0 mm
:post-flexion
DF
AF
P1F
P2F
PCR
My
: 26
: 28
: 13
: -: 12
: --
SL: 8.39 mm
Morphological Description
• Body deep and compressed in
moderated body shape.
• Tail pigment present in pre flexion
period.
• Dorsal spine formed since pre flexion.
• There isn’t any pelvic fin ray. Only
pelvic spines which forms as early as
short bud.
BL: 2.91 mm
• Body shape going elongated as its
growth.
BL: 3.82 mm
TL: 10.95 mm
SL: 8.39 mm
Similar Features with Other Family
• Identify monacanthid larvae through its characteristic, e.g. compressed body with
strongly coiled gut, pigment pattern, lack of pelvic fins, anterior position of the dorsal fin
spine, and dermal spinules.
• Monacanthid has small melanophores (which there’re large melanophores of
pomacentrids).
• Early dactylopterid larvae have pigment similar to that of monacanthids, but the former
have extensive head spination lacking in the latter.
• Triacanthids and some monacanthids are very similar. The 1st spinules of triacanthids
form on the preopercle, but they don’t form a raised tuft as in morph 1 monacanthids.
• Morph 1 monacanthids are more compresed than balistids, have earlier forming dorsal
fin spines and body spinules, have a less conspicuous preopercular spinule tuft, are less
heavily pigmented and most species have more myomeres.