A
Anlage – Rudimentary form of an anatomical structure; primordium; a German German word the plural of which is Anlagen.
B
body depth – The vertical distance between body margins (exclusive of fins) through the anterior margin of the pectoral-fin base: not necessarily the greatest body depth.
body length – Size of the larva; corresponds to notochord length in preflexion and flexion larvae and to standard length after flexion.
body width – The transverse distance between body margins at the pectoral-fin base.
C
choroids fissure – Line of juncture of invaginating borders of the optic cup; apparent in young fish as a trough-like area below lens.
choroids tissue – An undifferentiated mass of (usually) unpigmented tissue adhering to the ventral surface of the eye (see Moser & Ahlstrom 1970).
cleithral symphysis – The cartilaginous joint between the two cleithra where they join ventrally Often forms a prominent point along the ventral profile.
cleithrum – Prominent bone of pectoral girdle, clearly visible in many fish larvae. D
demersal egg – An egg which remains on the bottom either free or attached to the substratum.
E
exterilium larva – A term referring to the larvae of some unidentified species of the ophidiid subfamily Neobythinae characterized by an elongate, compressed body and a very long, trailing gut ornamented with flaps and streamers (illustrations are found in Gordon et al., 1984 C); Okiyama, 1988d (p. 340).
eye diameter – The horizontal distance across the midline of the pigmented region of the eye.
F
fin elements – Fin supports; spines and soft rays.
finfold – Medial fold of integument that extends along body of developing fishes and from which
media fins arise.
fin length – Length of the longest soft ray of designated fin.
flexion – Bending upward of the notochord tip as part of the process of caudal-fin formation. flexion larva – Development stage beginning with flexion of the notochord and ending with the
hypural bones assuming a vertical position.
G
gas bladder – Membranous, gas-filled organ located between the kidneys and alimentary canal in teleost fishes; air bladder or swim bladder.
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H
head length – The horizontal distance from the tip of snout to posterior-most part of opercular membrane; prior to development of operculum, measured to the posterior margin of cleithrum.
head width - The transverse distance between margins at the widest area of the head. Not applicable to larvae with flared opercles.
Hypural bones – The basal bones of the caudal fin that support the caudal-fin rays.
I
incipient fin-ray – Early stage in fin-ray development; and unossified thickening in finfold articulating with the fin base.
initially – When used in the Morphology section, meaning in the smallest available specimens. interopercle – A bone of the skull that may bear spination (see Fig. 2).
J
juvenile – Developmental stage from attainment of full external meristic complements and loss of temporary specializations for pelagic life to sexual maturity.
K
lachrymal – The anterior bone of the infraorbital series. Frequently overlaps the maxilla when the mouth is closed.
larva- Developmental stage between hatching (or birth) and attainment of full external meristic complements (fins and scales) and loss of temporary specializations for pelagic life; yolk-sac through postflexion stage inclusive.
M
melanin – A black pigment.
melanophores – Melanin-bearing cells (brown to black); frequently capable of expansions and
contractions which change their size and shape.
mouth width – The gape; transverse distance between corners of the mouth. myomeres – Serial muscle bundles of the body.
myosepta – Connective tissue partitions separating adjacent myomeres.
N
notochord - Longitudinal supporting axis of body which is eventually replaced as a support by the vertebral column in teleostean fishes.
notochord length – Straight line distance from tip of snout to posterior tip of notochord; used prior to and during flexion.
O
olfactory pit – A shallow depression on the snout from which olfactory organ develops.
opercle (operculum) – Bone of the skull that may bear spination (see Fig. 2).
ossification – Hardening of bony parts through deposition of calcium salts; usually detected by
staining with alizarin
otic capsule – Sensory anlage from which the ear develops; clearly visible during early development
P
parahypural – Modified haemal spine of the penultimate vertebral centrum. Supports some caudal- fin rays.
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pectoral bud – Swelling at site of future pectoral fin; anlage of pectoral fin.
pelagic – In the water column as distrinct from substrate-associated; neither necessarily planktonic
nor oceanic.
pelagic egg – Egg which floats freely in the water column, often slightly positively buoyant. pelagic juvenile – Pre-settlement juvenile of a species that is benthic or reef-associated as an adult. pelvic bud – Swelling at site of future pelvic (ventral) fin; anlage of pelvic fin.
postanal mymeres – Myomeres posterio