1. 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.

2. Review of Morphological Features
Body shape
Deep to elongate, becoming angular with growth. Compressed.
Deep, becoming deeper with growth, but remaining rounded.
Body depth
preflex
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
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)

3. Review of Morphological Features (contd.)
Size at flexion mm mm
Notochord tip
Long and persist in postflexion larvae
Doesn't persist in postflexion larvae
Identified taxa included
Aluterus, Amanses, Cantherhines, Monacanthus, Oxymonacanthus, Pseudalutarius, Stephanolepis, Thamnaconus
Brachaluteres, Paraluteres, Rudarius.

4. Review of Morphological Features (contd.)
Table of Meristic Character
Genus D A P1 C
Vert
Acreichthys II
25-29
10-12 12
7+13
Aluterus II
46-54
13-15
7+(14-16)
Amanses II
22-25 13
7+12
Anacanthus I
56-62
8-10
7+(22-24)
Brachaluteres II
20-27
Cantherhines II
28-35
11-15
Cantheschenia II
32-36
10-14
Chaetodermis II
23-25
11-13
Colurodontis II
26-31
Eubalichthys
33-37
12-14
Lalmohania
25-28
10-11
Monacanthus II
27-34
11-14
Oxymonacanthus II
23-32
8+(17-18)
Paraluteres II 24
11-12
7+(13-14)
Paramonacanthus II
24-34
10-13
(6-7)+(12-13)

5. Review of Morphological Features (contd.)
Table of Meristic Character
Genus D A P1 C
Vert
Pervagor II
25-36
10-14 12
7+12
Pseudalutarius II
41-46
11-12
8+(18-21)
Pseudomonacanthus II
27-34
10-13
Rudarius II
20-28
7+(12-13)
Stephanolepsis
29-34
Thamnaconus II
30-37
12-16

6. 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.

7. Information of Sampling (Contd.)
Sampling track.

8. Figure
BL: 2.91 mm
BL: 3.47 mm
BL: 3.48 mm
BL: 3.54 mm

9. Figure
BL: 3.82 mm
BL: 4.02 mm
BL: 4.03 mm
BL: 4.45 mm

10. Detail of Illustrated Specimen
TL: mm
SL: 8.39 mm
TL : mm
BD : 4.0 mm
ED : 1.2 mm
SnL : 8.5 mm
PAL : 5.0 mm
Stage :post-flexion
DF : 26
AF : 28
P1F : 13
P2F : --
PCR : 12
My : --

11. 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.
Body shape going elongated as its growth.
BL: 2.91 mm
TL: mm
SL: 8.39 mm
BL: 3.82 mm

12. 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.