View data on Catalog of Fishes here.
The body of metamorphosed females is short, its depth at the base of the pectoral fin 55–70% SL. The length of the head is 50–60% SL. The sphenotics, frontals, and preopercles all bear strong prominent spines. The preopercular spine is compressed, its distal one-half normally divided into 2–5 short broad cusps (in one specimen the spine is undivided on the left side), the upper- and lowermost spine more-or-less strongly curved. The lower jaw bears a symphysial spine. The ventral edge of the articulars is straight.
The nostrils of females are set on elongate papilla. The lateral-line organs are stalked and unpigmented. The pterygiophore of the illicium is short, completely embedded in the skin of the head. The escal bulb is sessile and spherical or distally flattened, with a diameter of about 10% SL, and completely unpigmented except for the inner wall of the photophores. There is a single short posterior escal appendage, divided distally into 2–6 short branches, simple in some juveniles.
The teeth of females are slender, recurved, and depressible, the longest about 5% SL. There are 50–80 teeth on each side of the upper and lower jaws in 40–60 mm specimens, arranged in several diagonal series, 6 to at least 10 oblique longitudinal series, and a greater number of oblique transverse series, increasing with the size of specimens.
The skin of females is totally unpigmented, the peritoneum black. Secondary subdermal pigmentation spreads posteriorly with increasing size of specimens from an anterior concentration on the dorsal surface of the trunk. It also spreads anteriorly from the base of the caudal fin, gradually obscuring the pattern of larval melanophores, and completely covering the body musculature of adults, except for the myosepta. The skin of free-living and parasitic males is also unpigmented.
The body of free-living and parasitic males is elongate. The roof of the skull is not strongly arched. Sphenotic spines are absent or represented only by a small blunt knob. The dorsal contour of the body is straight to slightly convex. The teeth are recurved and depressible. There are 20–24 on each side of the upper and lower jaws, arranged in four very distinct oblique longitudinal series, each with the length of teeth increasing posteriorly. The longest teeth are 3–4% SL and 2–4 times the length of the denticular teeth. Some jaw teeth are lost in larger parasitic males.
The eyes of males are directed anteriorly; they are slightly tubular, with diameters of 6–7% SL. The olfactory organs are situated on the sides of the blunt snout, well separated from the eyes and inflated, their greatest diameter about 6% SL. The anterior nostrils are directed anteriorly, about one-half the size of the posterior nostrils. The olfactory organs and eyes are degenerated in the largest parasitic males.
The skin of free-living and parasitic males is unpigmented. Subdermal pigment is present on the peritoneum and in two series of melanophores along the sides of the body: a dorsal series frequently consisting of a single row of melanophores, but sometimes two or three melanophores in width; and a ventral series of melanophores two to several melanophores in width. The dorsal and ventral series fuse to form a single group of melanophores at the base of the caudal fin.
The body shape and patterns of jaw-teeth and subdermal pigmentation of the larvae are as described for free-living males. The numbers of teeth and melanophores increase with the size of specimens. Except for metamorphic stages, the larvae are inseparable from those of the Linophryne subgenus Rhizophryne.
Fin-ray counts are shared by females and males: the dorsal and anal fins each contain 3 rays, the pectoral-fin 15 or 16 rays. The caudal-fin contains 9 rays, the ninth ray about one-half the length of the eighth.
Females reach a maximum known length of 159 mm (NMNZ P.21248); free-living males, 16 mm (MCZ 32308); and parasitic males, 15 mm (AMS I.21365-8).
Metamorphosed females of Haplophryne are distinguished from those of all other ceratioids by having unpigmented skin and a single compressed preopercular spine consisting of 2–5 radiating cusps. They differ further from those of all other genera of the family in having the following combination of character states: The frontals are widely separated, each with an anterodorsal spine. Epiotic and posttemporal spines are absent. The maxillae is reduced and extremely slender. The teeth are relatively short and numerous, placed in several overlapping oblique longitudinal series. Vomerine teeth are absent, The first pharyngobranchial is absent. The ceratohyal lacks an anterodorsal process. The posterior margin of the hypural plate is notched. The ninth caudal-fin ray is about one-half the length of the eighth ray. The illicium is extremely short, the escal bulb sessile on the snout. There is only a single escal appendage. A hyoid barbel is absent. The second pectoral radial is broader than the third.
The free-living males of Haplophryne are distinguished from those of all other genera of the family by having the following combination of character states: The sphenotic spines are weak, nearly absent. The preopercle is slender and angled at mid-length. The epiotic region of the skull is only moderately elevated. The premaxillae are well developed. There are 20–24 teeth on each side of the upper and lower jaws, arranged in four series. The longest jaw teeth are longer than the denticular teeth. There is a transverse series of 3–6 upper denticular teeth, more-or-less completely fused at the base to form a small upper denticular bone. A pair of lower denticular bones are widely spaced near tip of lower jaw, each with 1–3 denticular teeth. All the denticular teeth are short and not meeting in front of the closed mouth. The olfactory organs are moderately enlarged and inflated, nearly as large as the eyes. The posterior nostril is well separated from the eye. There are 5–7 olfactory lamellae. The skin is everywhere unpigmented.
The larvae of Haplophryne are distinguished from those of all other genera of the family by having the following character states: Sphenotic spines are absent. There are two series of melanophores along the sides of the body, coming together at the base of the caudal fin to form a single more-or-less dense cluster. The pectoral fins are relatively small.
Haplophryne mollis is known from all three major oceans of the world, the majority of the localities scattered over the North Atlantic between about 40°N and 40°S, including six females from the Western North Atlantic and Caribbean Sea. Most Pacific specimens are from off eastern Australia, New Zealand, and New Caledonia, but single specimens have been recorded from Hawaii and the Gulf of Panama. The species is represented in the Indian Ocean only by the holotype of Aceratias mollis and one free-living male.
Meso- to bathypelagic. All known specimens were caught in non-closing pelagic trawls. Of the 48 females, three specimens in metamorphosis were caught at maximum depths of 300 m, 10 others including six with parasitic males in maximum depths ranging from 550–900 m, and 12 others in nets with greater maximum fishing depth. With the exception of one specimen captured in less than 200 m, the 12 known free-living males came from hauls with maximum depths of more than 1500 m.
As with all species of the family, dwarted males of H. mollis attach to females as sexual parasites, fusing tissues and ostensibly relying on the female for energy.
In contrast to Borophryne and Linophryne in which males are nearly always found upside down, facing forward, and attached to the belly close to the anus, those of Haplophryne may be found facing in any and all directions, almost anywhere on the head and trunk, and even, in one case, on the esca of the female. In contrast also to the parasitic males of all other ceratioids (except for a few specimens of Ceratias), a prominent nipple-like papilla of tissue projects from the female, more or less filling the mouth of the male. This papilla, if developed prior to actual fusion of male and female tissues, may facilitate the earliest stages of attachment by procuring a firmer hold for the male teeth. At the same time, however, the papilla, in filling the mouth cavity of the male, would seem to “represent a hindrance for the establishment of effective respiratory currents across the male gills.” The majority of the attached males, however, have retained an opening to the pharynx on each side, although one has lost the opening on one side, and three are so deeply embedded in female tissue that the mouth has become completely closed.
The 75 known females of Haplophryne mollis include 25 specimens that bear one to six parasitic males; three others bear a scar on various parts of the body that represents a lost male. Such scars are not known in any other ceratioid (white circular scars, one each on four specimens and four species of Himantolophus, are most probably the result of prior attachment of parasitic copepods). While the scars and most of the parasitic males are found on the belly of the females, several males are attached in various places on the head; especially remarkable is the position of a 12-mm male (AMS I.21365-008) attached to the distal surface of the esca of the female is somewhat larger (15 mm) and distinctly more bulky than the largest known free-living male, indicating growth based on true parasitism. Several of the parasitic males have large, apparently ripe testes, but no females with eggs larger than 0.15 mm in diameter have been reported.
Seventy-five metamorphosed and metamorphic females (21–159 mm), 43 parasitic males (8.9–15 mm), 20 free-living metamorphosed and metamorphic males (10–16 mm), and about 250 ‚ÄúHyaloceratias‚Äù larvae (2.6–17.5 mm).
VALDIVIA station 175, Indian Ocean, 26°3'S, 93°43'E, open pelagic net, 0–2200 m, 12 January 1899.
Holotype of Aceratias mollis: ZMB 17713, male, 13 mm.
Haplophryne mollis, the ghostly seadevil or soft leftvent angler, is a species of anglerfish in the family Linophrynidae and is the only species in the genus Haplophryne. It is found in the bathypelagic and mesopelagic zones of tropical and subtropical parts of the world's oceans at depths down to about 2,250 m (7,400 ft).
Adult female Haplophryne mollis are much larger than adult males, with a maximum length of 16 cm (6.3 in), but 8 cm (3 in) is a more common length.[3] As in other angler fish, the front dorsal fin is replaced by a lure (illicium or esca) that protrudes forward and over the mouth to attract prey, but in this species this just consists of a flap of skin and there is no "fishing rod". The fish has spine-like ornamentation above the eyes and at the corners of the jaws. The head is large and angular, with a very wide mouth armed with numerous small teeth in both jaws. The dorsal fin, which has no spines but consists of three soft rays, is set far back on the body; the anal fin also has three soft rays and the tail is rounded.[3]
Unlike most other deepsea anglerfish, H. mollis lacks pigmentation, and both sexes appear pallid and translucent, with the musculature and portions of the skeleton clearly showing through the skin. Free-living males only grow to about 2 cm (0.8 in), and differ from the adult and juvenile females by the noticeable lack of a short, bubble-like esca and having comparatively small fins. Juvenile females lack the spinous ornamentation on the head.[4]
Because of the great depths at which this fish lives, it is seldom encountered by humans. In 2009 it was reported that 88 known female specimens had been observed. The type specimen was described by the German zoologist August Brauer in 1902 from the Indian Ocean. Another Indian Ocean specimen was a free-living male caught off Western Australia. Other specimens have been trawled from the Atlantic Ocean, the Caribbean Sea and the Gulf of Mexico, between 55°N and 40°S. Further specimens have been found in the Pacific Ocean off eastern Australia, New Caledonia and New Zealand, with isolated findings near Hawaii and in the Gulf of Panama.[5] It is found in the bathypelagic and mesopelagic zones of tropical and subtropical parts of the world's oceans at depths down to about 2,250 m (7,400 ft).[3]
Male H. mollis are at first free-living, but when they have found a female they latch onto her with their teeth. In most anglerfish the point of attachment for the male is on the belly, close to the anus, but in H. mollis the attachment site can be anywhere on the head or body, and in one case, a male attached to the female's esca (lure). The males orient themselves in random directions, and there may be more than one male per female. A papilla, or conical fleshy protuberance, grows at the site of attachment which may assist the male to establish a good grip. The mouth of the male is partially blocked by the papilla, but an opening usually remains at either side which suffices for allowing a flow of water over the gills. As time passes, the male becomes fused to the female and their tissues combine. The male can be considered as a parasite of the female but only about 30% of mature females encountered have an attached male, so many females may never encounter a mate, and remain in a solitary, non-reproductive state for the duration of their lives.[6]
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Haplophryne mollis female anglerfish with atrophied males attached Haplophryne mollis, the ghostly seadevil or soft leftvent angler, is a species of anglerfish in the family Linophrynidae and is the only species in the genus Haplophryne. It is found in the bathypelagic and mesopelagic zones of tropical and subtropical parts of the world's oceans at depths down to about 2,250 m (7,400 ft).
