(Valenciennes)
1. Distinctive characters of early developmental stages
(a) Eggs and larvae
Not recorded from the mangroves.
(b) Early juveniles (based on 24 mm specimen)
Hyporhamphus xanthopterus 1
Caudal forked; lower jaw elongated; lower jaw tip coral red in colour. (All the six species described (vide Zenarchopterus brevirostris 1) under the family Hemiramphidae were reported to possess lower jaw with bright red fleshy tip, which seem to be too generalized. In the absence of description about H. xanthopterus and H. erythrorhynchus by the author, the statement needs further confirmation.) Anal fin originates opposite to dorsal. Scales yet to develop. Pigmentation in the lateral band prominent. Pelvic fin yet to move forward to reach the position prevailing in adult.
2. Distinguishing characters of early developmental stages in species occurring in the adjacent coastal water
(a) Post larvae and early juvenile of Hemiramphus far
Hemiramphus far 1
No prominent lateral band with pigmentation (often found in adults). Tip of elongated lower jaw not red in early juveniles. Anal fin originates behind the dorsal fin origin. Juveniles and adults have no scales on snout and no preorbital ridge. (Juveniles and adults of H. xanthopterus have scales on snout and preorbital ridge is present).
(b) Early juveniles and juveniles of Rhynchorhamphus georgii and R. malabaricus (Collette, 1984b and Collette, 1976)
Nasal papilla present (absent in H. xanthopterus ). More gill rakers on 1st gill arch - 47 to 78. (In H. xanthopterus only 41 - 53 number of gillrakes are present in 1st gill arch). Two branches of lateral lines run behind opercle and pectoral fin origin. (Only one branch in H. xanthopterus ).
3. Salient biological characteristics
(a) Maximum size
150 mm total length.
4. Salient ecological information
Inhabits coastal waters and frequently enters mangroves and estuaries. Early juveniles rarely occur in the mangrove waterways. It is distributed in the Indo-Malayan archipelago. In general, species of the genus Hyporhamphus and genus Hemiramphus with relatively lesser number of gill rakers on first arch (19-53) occur in mangroves frequently, whereas, the species of the genus Rhynchorhamphus with more number of girl rakers on first arch (47-78) avoid turbid mangrove waters, probably due to the niche specific ecological adaptation).