| Abyssobrotula galatheae | |
|---|---|
 | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Ophidiiformes |
| Family: | Ophidiidae |
| Genus: | Abyssobrotula |
| Species: | A. galatheae |
| Binomial name | |
| Abyssobrotula galatheae J. G. Nielsen, 1977[2] | |
Abyssobrotula galatheae is aspecies ofcusk eel in thefamilyOphidiidae.[1][3] It is the deepest-livingfish known; one specimen,trawled from a depth of 8,370 m (27,460 ft) in thePuerto Rico Trench in 1970, holds the record for the deepest fish ever captured.[4] Although generally recognized, some have suggested that the record-breaking individual might have been caught with a non-closing net (a net that is open on the way up and down into the deep) and therefore perhaps caught shallower.[5]
The first examples of this fish were misidentified by Staiger asBassogigas profundissimus, before being described as a new species by Jørgen G. Nielsen in 1977.[6] The species name refers to the research shipHDMSGalathea, which captured the first specimens during thesecond Galathea expedition.[2]
Though uncommon, this species is known from alltropical andsubtropical oceans. It occurs in theabyssal andhadal zones below a depth of 3,110 m (10,200 ft). It isbottom-dwelling in nature, although one individual has been captured from thewater column in theGulf of Panama. Its diet consists ofpolychaete worms andcrustaceans, such asisopods andamphipods.[2] Reproduction isoviparous, possibly withpelagic eggs floating in agelatinous mass as in other members of the family.[3]
This species grows to 16.5 cm (6.5 in)standard length.[3] It has a shorthead with a downward inflection, a swollensnout and aninferiormouth. The body is soft, with a taperingtail and loose, transparentskin. Both the body and the head are covered withscales. Theteeth are small and pointed, arranged in irregular rows; the two median and single pair of basibranchial (on the most ventralgill arch) tooth patches are distinctive for this species. Theeyes are tiny, deep-set, and hidden. They are unlikely to be functional, but there is a well-developed system ofsensorypores on its head. Thelateral line is visible only on the frontmost part of the body and lacks developed pores.[2]
Externally,A. galatheae can be distinguished from other deep-sea ophidioids by its longpectoral fins, which contain only 10–11fin rays each, and its flat, weakly developedopercularspine. The longdorsal andanal fins contain 97–116 and 76–96 rays respectively. Thepelvic fins andcaudal fin are small and contain 2 and 8 rays respectively. The coloration is yellowish; thebranchial cavity is black and theperitoneum dark brown. Theskeleton is well-ossified, consistent with abenthic lifestyle; there are 18–21 precaudalvertebrae.[2]
