The genus Isogomphodon of requiem sharks only consists of one living species, but it seems that the Daggernose shark (Isogomphodon oxyrhynchus), known since 1839, soon joins the fate of its extinct sister species Isogomphodon acuarius.
Female Daggernose sharks are viviparous (placental connection after the yolk sac of the embryo is depleted) and give birth to 2 to 8 living young every two years in nursery areas. Newborn sharks measure 15 to 17 in -38 to 43 cm- in length. Males mature at an age of 5–6 years and females with 6–7 years and reach up to 12 years and 4.6 ft -1.4 m- (males) and 20 years and 5.2 ft -1.6 m- (females).
The Daggernose shark lives solely in coastal waters (no rivers since it is intolerant of fresh water) of the Western Atlantic off Trinidad, Guyana, Suriname, French Guiana and northern Brazil. It is highly specialised (tiny eyes but elongated snout to properly use electroreception, a lot of pointed slender teeth -the most teeth of all requiem sharks- to form a fish trap) to hunt small schooling fish in muddy waters. Since humans are after the same fish, the shark gets the short end of the stick – caught as bycatch in gillnets (but also by fishery targeting sharks), it has been considered critically endangered by the IUCN since 2006 as a result. Between 1992 and 2002 it suffered a very large population decline (shown by more that 90% less catches), and moreover, mostly juvenile specimens have been found in the nets. And things may have gotten worse since then. There are simply no new data available regarding daggernose sharks, not for lack of trying but specimen, which means they are (despite being legally protected in Brazil since 2006, which is without enforcement not of much use) in reproductive collapse and on the brick of extinction.