Caulophryne jordani

Caulophryne jordani was first formally described in 1896 by the American ichthyologists George Brown Goode and Tarleton Hoffman Bean with its type locality given as the Gulf Stream off Long Island, New York at 39°27'N, 71°15'W, Albatross station 2747 from a depth between {{cvt|0|and|1276|fathom}}.{{Cof genus|genus=Caulophryne|access-date=24 June 2024}} When Goode and Bean described the species they placed it in a new monospecific genus, Caulophryne, so this species is the type species of that genus by monotypy.{{Cof family|family=Caulophrynidae|access-date=24 June 2024}} Caulophryne is one of two genera within the family Caulophrynidae. The 5th edition of Fishes of the World classifies the Caulophrynidae within the suborder Ceratioidei of the order Lophiiformes, the anglerfishes.{{cite book |author1=Nelson, J.S. |author1-link=Joseph S. Nelson |author2=Grande, T.C. |author3=Wilson, M.V.H. |year=2016 |title=Fishes of the World |edition=5th |publisher=John Wiley & Sons |place=Hoboken, NJ |pages=508–518 |isbn=978-1-118-34233-6 |lccn=2015037522 |oclc=951899884 |ol=25909650M |doi=10.1002/9781119174844}}

Caulophryne jordani is a species within the genus Caulophryne, this name is a combination of caulis, which mean" stem", an allusion to the stem-like base of the illicium, with phryne, meaning "toad", a suffix commonly used in the names of anglerfish genera. Its use may date as far back as Aristotle and Cicero, who referred to anglerfishes as "fishing-frogs" and "sea-frogs", respectively, possibly because of their resemblance to frogs and toads. The specific name honours the American ichthyologist, educator, and eugenicist David Starr Jordan, the president of Leland Stanford Jr University in California, in recognition of his work in the field of ichthyology.{{cite web |url=https://etyfish.org/lophiiformes2/ |title=Order LOPHIIFORMES (part 2): Families CAULOPHRYNIDAE, NEOCERATIIDAE, MELANOCETIDAE, HIMANTOLOPHIDAE, DICERATIIDAE, ONEIRODIDAE, THAUMATICHTHYIDAE, CENTROPHRYNIDAE, CERATIIDAE, GIGANTACTINIDAE and LINOPHRYNIDAE |author=Christopher Scharpf |date=3 June 2024 |access-date=24 June 2024 |work=The ETYFish Project Fish Name Etymology Database |publisher=Christopher Scharpf}}

Like all deep-sea anglerfish, Caulophryne jordani has a high degree of sexual dimorphism. The females have short, round bodies with large mouths. The lower jaw reaches back past the base of the pectoral fin.{{Verify source|date=March 2025}} The teeth in the jaws are thin, backwards curving and depressible. The morphology of the esca and illicium distinguish C. jordani from its congeners; the illicium in this species, which ranges between 16.8% and 36.8% of the standard length, is pigmented apart from the area near the esca. There are between 5 and 14 elongated translucent filaments along the whole length of the illicium, all of these except for the ones nearest the esca have their origin on the rear margin of the illicium. The relatively simple esca (the lure, which lacks a bulb) has a long, filamentous appendage arising from its side towards the front, two appendages on its tip which each have many filaments, thicker toward the front of the appendage and thinner towards the rear. These filaments are opaque along the rear margin and the rearmost are the thinnest. The appendage on the side of the esca near its front has many short filaments and has a palmate and opaque tip.{{cite book |author=Theodore W. Pietsch Ph.D. |author-link=Theodore Wells Pietsch III |year=2009 |title=Oceanic Anglerfishes: Extraordinary Diversity in the Deep Sea |pages=446–447 |publisher=University of California Press |isbn=978-0520942554 |url=https://books.google.com/books?id=HiOq3dUk7jIC&q=Caulophryne+bacescui&pg=PA538}}

The females have highly elongated dorsal and anal fins, with the soft rays of these fins resembling long threads. There are 8 fin rays in the caudal fin, between 16 and 19 rays in the dorsal fin, and between 14 and 18 rays in the anal fin. They do not have pelvic fins post-metamorphosis, as typical for the suborder. The sensory cells of the lateral line system are at the tips of the filamentous rays of the dorsal and anal fins. The skin is naked and they do not have any dermal spines. The maximum published total length for the females is {{cvt|20|cm}}.{{FishBase|Caulophryne|jordani|month=February|year=2024}}

The males are much smaller than the females, being {{cvt|1.6|cm}} in total length,{{cite web |author=Bray, D.J. |year=2018 |title=Caulophryne jordani |work=Fishes of Australia |access-date=24 June 2024 |url=https://fishesofaustralia.net.au/home/species/3425 |publisher=Museums Victoria}} and have more elongated bodies. They have large eyes and large nostrils, with large olfactory receptors. They have no teeth in the jaws, although there are tooth-like structures (denticles) on the jaw bones at the very front of the jaws which are used to attach to the larger female. The male do not have elongated dorsal and anal fins but have large pectoral fins like the females.{{cite web |author=Dianne J. Bray |title=Fanfin Anglers, CAULOPHRYNIDAE |work=Fishes of Australia |access-date=24 June 2024 |publisher=Museums Victoria |url=https://fishesofaustralia.net.au/home/family/120}}

Caulophryne jordani has a circumglobal distribution, although most records come from the Eastern Atlantic Ocean, Southern Ocean and the Indo-Pacific region. It is a bathypelagic species that has been recorded at depths between {{cvt|100|and|1510|m}}.

Caulophryne jordani is a predator on other fishes. They reproduce by means of pelagic eggs which hatch into pelagic larvae. The short, rounded larvae have swollen skin and well-developed pectoral and pelvic fins, the pelvic fins being lost as they metamorphose. Both larval males and females have a basic illicium. Metamorphosis starts at a standard length of {{cvt|8|to|10|mm}}. The large, well-developed eyes and olfactory apparatus of the metamorphosed males are used to detect and home in on a species specific chemical released by the female to attract males. When the male finds a female he bites her and the tissue and circulatory systems of the pair may fuse; if fusion occurs he becomes a sexual parasite on the female and is nourished by her through shared blood. For the remainder of his life he may remain attached to the female and fertilises her eggs.{{cite web |url=https://www.washington.edu/news/2018/03/22/a-blind-date-in-the-deep-sea-first-ever-observations-of-a-living-anglerfish-a-female-with-her-tiny-mate-coupled-for-life/ |title=A blind date in the deep sea: First-ever observations of a living anglerfish, a female with her tiny mate, coupled for life |date=22 March 2018 |access-date=8 March 2025 |website =UWNews |publisher=University of Washington}} The genus as a whole is thought to practice facultative sexual parasitism as specimens of C. jordani have well developed ovaries despite lacking attached males; in species which exclusively practice sexual parasitism, both sexes mature (and gonads ripen) only after fusion is achieved. This genus may be limited to one male attached at a time per female, but more evidence is needed to conclusively determine this assumption.{{cite journal |last1=Pietsch |first1=Theodore W. |title=Dimorphism, parasitism, and sex revisited: modes of reproduction among deep-sea ceratioid anglerfishes (Teleostei: Lophiiformes) |journal=Ichthyological Research |date=August 2005 |volume=52 |issue=3 |pages=207–236 |doi=10.1007/s10228-005-0286-2 |bibcode=2005IchtR..52..207P |url=https://link.springer.com/article/10.1007/s10228-005-0286-2 |issn=1341-8998|access-date=1 March 2025}}{{rp|216}}

A pair of C. jordani was observed in situ by a submersible of the Rebikoff-Niggeler Foundation in 2018, which was the first time this species was observed alive.{{cite journal |title=The anglerfish's deep-sea light show is revealed. |journal=Science |date=23 March 2018 |volume=359 |issue=6382 |pages=1311 |issn=0036-8075}} The extended fin rays were observed to billow all around the female, adorned with pinpoints of bioluminescence. It is thought that these filamentous rays, each independently controlled by muscles at the base, fulfill a similar role to a cat's whiskers, acting as a "network of sensory antennae, a kind of sphere of tactility around the fish", which would allow the female to detect nearby prey items. The bioluminescence on the fin rays is speculated to be mimicry of a larger or unpalatable organism, such as a jellyfish with stinging tentacles. Alternatively, they may supplement the illicium in luring prey closer.{{cite web |title=Elusive Deep-Sea Anglerfish Seen Mating for the First Time |url=https://www.smithsonianmag.com/smart-news/rare-footage-captures-mating-behavior-elusive-deep-sea-anglerfish-180968584/ |website=www.smithsonianmag.com |publisher=Smithsonian Magazine |access-date=8 March 2025}}

{{Commons category|Caulophryne jordani}}

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Category:Caulophrynidae

Category:Deep sea fish

Category:Fish described in 1896

Category:Taxa named by George Brown Goode

Category:Taxa named by Tarleton Hoffman Bean