Beaked salmon
Gonorynchus greyi
The sandfish ( Gonorynchus ) are the only extant genus of Gonorynchidae family and include five species. The fish live in the Indo-Pacific and are also sporadically in the southern Atlantic off. Sand fish are fished commercially. In their range they also name ( translated) as "beak salmon " or " rat fish " ( because of the long pointed snout ).
Features
They have an elongated brownish body, a vorstreckbaren upper jaw ( the maxilla is large, the premaxilla but very small ) and a single Bartel under the tip of the rostrum, by the small mouth quite inferior (similar to the sturgeons ( Acipenseridae ) or Chondrostoma ) is. The " lips " are somewhat lobed. Their dorsal fin is very far back and has 10 to 13 fin rays. Directly below the dorsal fin are the pelvic fins, behind the anal fin with nine to ten fin rays. A swim bladder is absent ( Grundfisch! deposits up to 700 m depth - Eyes large). The jaws are toothless, but on the Basihyale (the " tongue " ) and the Entopterygoid ( pairs ) are each one group of final teeth against. It is very striking that have the sandfish small ctenoid scales, which otherwise are only entitled to expect at the Stachelflossern - so it is an apomorphy by convergence. Another special feature is the "head ribs ": the first vertebra to the occipital grown (head to Browse or digging in " stiffened " ) - his " ribs " few, however, are not true ribs (as in the lung fish), but bones ( Patterson and Johnson 1995). Furthermore Gonorynchus has a simple structure, paired Epibranchialorgan ( Cruminale ) after the fourth Epibranchiale of the gill basket ( this symplesiomorphe feature of many Otomorpha is explained in more detail Heterotis niloticus ). The Branchiostegalmembran support four (rarely five) rays. The tail skeleton is by the fusion of the most important elements ( pu1 u1 u2 u n1 un2 php hu1 HU2 ) particularly stiffened (important for Quick Start to escape to ). Other anatomical features see below Notogoneus osculus.
Little is known about the spawning - it is in any case for free spawners - even though you put - in the plankton ( coastal ) and occasionally even finds the larvae quite frequently.
The largest species with 60 cm length is Gonorynchus gonorynchus, a benthic fish, the night goes on the hunt for invertebrates and digs during the day in the sand or mud (hence have the sandfish a " spectacle ", a transparent skin over the eyes).
Species
- Gonorynchus abbreviatus Temminck & Schlegel, 1846
- Gonorynchus forsteri Ogilby, 1911
- Gonorynchus gonorynchus (Linnaeus, 1766 )
- Gonorynchus greyi ( Richardson, 1845)
- Gonorynchus moseleyi Jordan & Snyder, 1923
Phylogeny
Fossil Gonorynchidae the family is occupied by the four genera Charitosomus, Judeichthys, Ramallichthys and Charitopsis from the Cretaceous of Lebanon, Israel and Germany. Another extinct genus is Notogoneus who lived from the Upper Cretaceous to Oligocene in North America, Europe and Australia in freshwater.