Schindleria brevipinguis (the stout infantfish) is one of the three smallest fish and vertebrates known. Only the male angler fish of the species Photocorynus spiniceps is shorter and only Paedocypris progenetica rivals it in terms of smallness of weight and volume. Schindleria brevipinguis, also known as a stout infantfish, is only about 7 millimeters (just over a quarter of an inch) long when fully grown. It inhabits Australia's Great Barrier Reef.

 

The first specimen of the stout infantfish was collected in 1979, by the Australian Museum's Jeff Leis, during fieldwork in the Lizard Island region of the Great Barrier Reef. But the fish was not properly studied for years, until H. J. Walker of the Scripps Institution of Oceanography, California, and William Watson of the Southwest Fisheries Science Center, La Jolla, turned their attention on it. Only six specimens of the stout infantfish have been found to date.

 

The females, at around 8.4 millimeters, appear to be slightly bigger than males, which typically measure around 7 millimeters. The species is described as being paedomorphic, which means that individuals retain many infantile characteristics, even when adult. The stout infantfish gets its name from this characteristic of paedomorphism and the fact that it is unusually stout compared to other species of infantfish. Its small size is matched by its short lifespan, which is thought to be a mere two months. However, this rapid turnover means that they may be able to adapt quickly as their environment changes – a talent that may be important in a habitat threatened by global warming.

 

Reference

1. Watson, W. & H. J. Walker Jr. 2004. The world's smallest vertebrate, Schindleria brevipinguis, a new paedomorphic species in the family Schindleriidae (Perciformes: Gobioidei). Records of the Australian Museum. 56(2): 139–142.