| Butidae Temporal range: | |
|---|---|
 | |
| Butis butis | |
 | |
| Ophiocara porocephala | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Gobiiformes |
| Suborder: | Gobioidei |
| Family: | Butidae Bleeker, 1874 [1] |
Butidae is a family of sleeper gobies in the order Gobiiformes. The family was formerly classified as a subfamily of the Eleotridae but the 5th Edition of Fishes of the World classifies it as a family in its own right. [2] Molecular phylogenetic analyses have demonstrated that the Butidae are a sister clade to the clade containing the families Gobiidae and Gobionellidae and that the Eleotridae is a sister to both of these clades. This means that the Eloetridae as formerly classified was paraphyletic and that its subfamilies should be raised to the status of families. [3]
The species in the Butidae are largely restricted to tropical and sub-tropical waters of Africa, Asia, Australia, and Oceania. They are especially diverse in New Guinea, Australia and New Zealand where they can be important components of brackish and freshwater ecosystems. [3] They are mostly quite small species but the marbled goby (Oxyeleotris marmorata) is a freshwater species of Buitdae from Southeast Asia that can grow to 65 cm (25.6 in) long and is an important food fish. [4] [5]
The earliest known member of the Butidae is the stem group-butid † Carlomonnius Bannikov & Carnevale, 2016 from the Early Eocene-aged Monte Bolca site of Italy. This genus is also the earliest gobioid known from skeletal remains. It was previously considered a gobioid of uncertain affinities [6] , but a 2025 study analyzing more specimens found strong evidence for it being closely related to the Butidae. Carlomonnius had a lifestyle unlike any extant butids, being a very small marine genus that inhabited reef environments, suggesting a similar lifestyle to coral gobies of the Gobiidae. This is unlike extant butids, which primarily inhabit freshwater and brackish habitats, with none inhabiting reef ecosystems. [7]
