Careproctus is a genus of snailfishes found in benthic and benthopelagic habitats in the Atlantic, Pacific, Arctic and Southern Oceans. Whether they truly are absent from the Indian Ocean (except for a couple of species in subantarctic waters) is unknown and might be an artifact of limited sampling. They range from shallow coastal seas in the far north of their range to the abyssal zone, at depths of . In the Northern Hemisphere they mostly live shallower than Paraliparis, but this pattern is reversed in the Southern Hemisphere. Although almost entirely restricted to very cold waters, a single species, C. hyaleius, lives at hydrothermal vents.
Its generic name is derived from the Ancient Greek úìÃÂñ (kára) "face, head" and ÃÂÃÂÃÂúÃÂÃÂà(prÃ
ÂktÃÂs) "anus", therefore literally meaning "butt-face", because of the position of the anus under the head.
Careproctus have one pair of nostrils and a ventral suction disc but lack a pseudobranch. They are tadpole-like in shape and reach up to in standard length, but most species are far smaller. Like other snailfish, they lack scales and have a loose gelatinous skin; a few species are covered in prickly spines.
Most species of Careproctus are poorly known, but they feed on small animals and some have unusual breeding behaviors. For example, C. ovigerus appears to be a mouth brooder where the eggs are carried and develop in the males' mouth. C. fulvus has a commensal relationship with glass sponges, laying their eggs in the paragastric cavity. Several other Careproctus species are parasitic on king crabs (such as Lithodes, Neolithodes and Paralithodes, and likely Echidnocerus), laying their egg mass in the gill chamber of the crab, forming a well-protected and well-aerated mobile "home" until they hatch. These parasitic Careproctus do not appear to be host specific, but rather they use various species of king crabs. An individual king crab may even carry the eggs of more than one Careproctus species at the same time. Additionally, small CareproctusâÂÂno more than longâÂÂhave been seen together with Lithodes and Paralomis king crabs, hitching rides by attaching themselves to the crab's legs or back. In contrast, a C. reinhardti (species complex) in an aquarium deposited its eggs on the glass, but whether this resembles its wild behavior is unknown.
Species
There are currently about 125 recognized species in this genus, but new species are regularly described and it is likely to actually contain more than 140. It formerly also included the species now separated in the genus Volodichthys.
- Careproctus abbreviatus <small>Burke, 1930</small>
- Careproctus acaecus <small>Andriashev, 1991</small> (appendage-less snailfish)
- Careproctus acanthodes <small>C. H. Gilbert & Burke, 1912</small> (toge snailfish)
- Careproctus aciculipunctatus <small>Andriashev & Chernova, 1997</small> (finely-speckled snailfish)
- Careproctus acifer <small>Andriashev & Stein, 1998</small>
- Careproctus aculeolatus <small>Andriashev, 1991</small> (small-spine snailfish)
- Careproctus albescens <small>Barnard, 1927</small>
- Careproctus ambustus
- Careproctus ampliceps <small>Andriashev & Stein, 1998</small>
- Careproctus armatus <small>Andriashev, 1991</small>
- Careproctus atakamensis <small>Andriashev, 1998</small>
- Careproctus atrans <small>Andriashev, 1991</small> (black snailfish)
- Careproctus attenuatus <small>C. H. Gilbert & Burke, 1912</small>
- Careproctus aureomarginatus <small>Andriashev, 1991</small> (marginate snailfish)
- Careproctus bathycoetus <small>C. H. Gilbert & Burke, 1912</small>
- Careproctus batialis <small>Popov, 1933</small>
- Careproctus bowersianus <small>C. H. Gilbert & Burke, 1912</small>
- Careproctus cactiformis <small>Andriashev, 1990</small>
- Careproctus candida <small>C. H. Gilbert & Burke, 1912</small> (bigeye snailfish)
- Careproctus canus <small>Kido, 1985</small>
- Careproctus carinatus <small>Chernova, 2014</small> (keel-belly snailfish)
- Careproctus colletti <small>C. H. Gilbert, 1896</small> (Alaska snailfish)
- Careproctus colliculi <small>Gerringer et al., 2025</small> (bumpy snailfish)
- Careproctus comus <small>J. W. Orr & Maslenikov, 2007</small> (comic snailfish)
- Careproctus continentalis <small>Andriashev & Prirodina, 1990</small>
- Careproctus credispinulosus <small>Andriashev & Prirodina, 1990</small>
- Careproctus crozetensis <small>Duhamel & N. J. King, 2007</small>
- Careproctus curilanus <small>C. H. Gilbert & Burke, 1912</small>
- Careproctus cyclocephalus <small>Kido, 1983</small>
- Careproctus cypseluroides <small>P. Y. Schmidt, 1950</small>
- Careproctus cypselurus <small>(D. S. Jordan & C. H. Gilbert, 1898)</small>
- Careproctus derjugini <small>Chernova, 2005</small> (Derjugin's snailfish)
- Careproctus discoveryae <small>Duhamel & N. J. King, 2007</small>
- Careproctus dubius <small>Zugmayer, 1911</small> (doubtful snailfish)
- Careproctus ectenes <small>C. H. Gilbert, 1896</small>
- Careproctus eltaninae <small>Andriashev & Stein, 1998</small>
- Careproctus falklandica <small>(Lönnberg, 1905)</small>
- Careproctus faunus <small>J. W. Orr & Maslenikov, 2007</small> (mischievous snailfish)
- Careproctus fedorovi <small>Andriashev & Stein, 1998</small>
- Careproctus filamentosus <small>Stein, 1978</small>
- Careproctus fulvus <small>Chernova, 2014</small> (fulvous snailfish)
- Careproctus furcellus <small>C. H. Gilbert & Burke, 1912, 1912</small>
- Careproctus georgianus <small>Lönnberg, 1905</small>
- Careproctus gilberti <small>Burke, 1912</small> (small-disk snailfish)
- Careproctus griseldea <small>Lloris, 1982</small>
- Careproctus guillemi <small>Matallanas, 1998</small>
- Careproctus homopterus <small>C. H. Gilbert & Burke, 1912</small>
- Careproctus hyaleius <small>Geistdoerfer, 1994</small>
- Careproctus improvisus <small>Andriashev & Stein, 1998</small>
- Careproctus inflexidens <small>Andriashev & Stein, 1998</small>
- Careproctus kamikawai <small>J. W. Orr, 2012</small> (arbiter snailfish)
- Careproctus karaensis <small>Chernova, 2014</small> (Kara snailfish)
- Careproctus kidoi <small>Knudsen & Møller, 2008</small> (Kido's snailfish)
- Careproctus knipowitschi <small>Chernova, 2005</small> (Knipowitsch's snailfish)
- Careproctus lacmi <small>Andriashev & Stein, 1998</small>
- Careproctus latiosus <small>Andriashev & Chernova, 2011</small> (broad-mouth snailfish)
- Careproctus leptorhinus <small>Andriashev & Stein, 1998</small>
- Careproctus lerikimae <small>J. W. Orr, Y. Kai & Nakabo, 2015</small> (dusty snailfish)
- Careproctus longifilis <small>Garman, 1892</small>
- Careproctus longipectoralis <small>Duhamel, 1992</small>
- Careproctus longipinnis <small>Burke, 1912</small> (long-feather snailfish)
- Careproctus lycopersicus <small>J. W. Orr, 2012</small>
- Careproctus macranchus <small>Andriashev, 1991</small>
- Careproctus macrodiscus <small>P. Y. Schmidt, 1950</small>
- Careproctus macrophthalmus <small>Chernova, 2005</small> (big-eye snailfish)
- Careproctus maculosus <small>Stein, 2006</small>
- Careproctus magellanicus <small>Matallanas & Pequeño, 2000</small>
- Careproctus marginatus <small>Kido, 1988</small>
- Careproctus maslenikovae J. W. Orr, 2021 (blushing snailfish)
- Careproctus mederi <small>P. Y. Schmidt, 1916</small>
- Careproctus melanuroides <small>P. Y. Schmidt, 1950</small>
- Careproctus melanurus <small>C. H. Gilbert, 1892</small> (black-tail snailfish)
- Careproctus merretti <small>Andriashev & Chernova, 1988</small> (Merret's snailfish)
- Careproctus mica <small>Chernova, 2014</small> (babbie snailfish)
- Careproctus micropus <small>(Günther, 1887)</small> (small-eye snailfish)
- Careproctus microstomus <small>Stein, 1978</small>
- Careproctus minimus <small>Andriashev & Stein, 1998</small>
- Careproctus mollis <small>C. H. Gilbert & Burke, 1912</small>
- Careproctus moskalevi <small>Andriashev & Chernova, 2012</small> (Moskalev's snailfish)
- Careproctus narilobus <small>Stein, 2012</small>
- Careproctus nigricans <small>P. Y. Schmidt, 1950</small>
- Careproctus notosaikaiensis <small>Y. Kai, Ikeguchi & Nakabo, 2011</small>
- Careproctus novaezelandiae <small>Andriashev, 1990</small>
- Careproctus opisthotremus <small>C. H. Gilbert & Burke, 1912</small>
- Careproctus oregonensis <small>Stein, 1978</small> (small-fin snailfish)
- Careproctus ostentum <small>C. H. Gilbert, 1896</small>
- Careproctus ovigerus <small>(C. H. Gilbert, 1896)</small> (abyssal snailfish)
- Careproctus pallidus <small>(Vaillant, 1888)</small>
- Careproctus parvidiscus <small>Imamura & Nobetsu, 2002</small>
- Careproctus parviporatus <small>Andriashev & Stein, 1998</small>
- Careproctus patagonicus <small>Matallanas & Pequeño, 2000</small>
- Careproctus paxtoni <small>Stein, Chernova & Andriashev, 2001</small> (blunt-tooth snailfish)
- Careproctus pellucicauda <small>Stein, 2012</small>
- Careproctus pellucidus <small>C. H. Gilbert & Burke, 1912</small> (pellucid snailfish)
- Careproctus phasma <small>C. H. Gilbert, 1896 (spectral snailfish)</small>
- Careproctus polarsterni <small>Duhamel, 1992</small>
- Careproctus profundicola <small>Duhamel, 1992</small>
- Careproctus pseudoprofundicola <small>Andriashev & Stein, 1998</small>
- Careproctus pycnosoma <small>C. H. Gilbert & Burke, 1912</small>
- Careproctus ranula <small>(Goode & T. H. Bean, 1879)</small> (froggy snailfish)
- Careproctus rastrinoides <small>P. Y. Schmidt, 1950</small>
- Careproctus rastrinus <small>C. H. Gilbert & Burke, 1912</small> (salmon snailfish)
- Careproctus rausuensis <small>Machi, Nobetsu & Yabe, 2012</small>
- Careproctus reinhardti <small>(Krøyer, 1862)</small> (sea tadpole)
- Careproctus rhodomelas <small>C. H. Gilbert & Burke, 1912</small>
- Careproctus rimiventris <small>Andriashev & Stein, 1998</small>
- Careproctus rosa <small>Chernova, 2014</small> (rose snailfish)
- Careproctus roseofuscus <small>C. H. Gilbert & Burke, 1912</small> (round snailfish)
- Careproctus rotundifrons <small>H. Sakurai & Shinohara, 2008</small>
- Careproctus sandwichensis <small>Andriashev & Stein, 1998</small>
- Careproctus scaphopterus <small>Andriashev & Stein, 1998</small>
- Careproctus scottae <small>W. M. Chapman & DeLacy, 1934</small> (peach-skin snailfish)
- Careproctus segaliensis <small>C. H. Gilbert & Burke, 1912</small>
- Careproctus seraphimae <small>P. Y. Schmidt, 1950</small>
- Careproctus shigemii
- Careproctus simus <small>[C. H. Gilbert, 1896</small>
- Careproctus sinensis <small>C. H. Gilbert & Burke, 1912</small>
- Careproctus solidus <small>Chernova, 1999</small> (firm-body snailfish)
- Careproctus spectrum <small>T. H. Bean, 1890</small> (stippled snailfish)
- Careproctus spiraki J. W. Orr, 2021 (pimpled snailfish)
- Careproctus steini <small>Andriashev & Prirodina, 1990</small>
- Careproctus stigmatogenus <small>Stein, 2006</small>
- Careproctus tapirus <small>Chernova, 2005</small> (tapir snailfish)
- Careproctus telescopus <small>Chernova, 2005</small> (telescope snailfish)
- Careproctus tomiyamai
- Careproctus trachysoma <small>C. H. Gilbert & Burke, 1912</small> (rough snailfish)
- Careproctus tricapitidens <small>Andriashev & Stein, 1998</small>
- Careproctus uter <small>Chernova, 2014</small> (drop-shaped snailfish)
- Careproctus vladibeckeri <small>Andriashev & Stein, 1998</small>
- Careproctus yanceyi <small>Gerringer et al., 2025</small> (dark snailfish)
- Careproctus zachirus <small>Kido, 1985</small>
- Careproctus zispi <small>Andriashev & Stein, 1998</small>
References