View data on Catalog of Fishes here.
The escal bulb of metamorphosed females bears a single distal filament (laid down as a small papilla in metamorphosing females as small as approximately 10 mm), with one to several pairs of smaller filaments arising from the base. The number of basal escal filaments, and length and branching of the distal filament, is highly variable. The number of teeth in the lower jaw ranges from 42 to 68. Vomerine teeth range from 2 to 10. Fin-ray counts are as follows: dorsal-fin rays 4 (excluding those embedded in the caruncles), rarely 5 (only three of 311 specimens counted); anal-fin rays 4; pectoral-fin rays 14–18, usually 15–17. The skin is covered with close-set dermal spinules. Larval females have a distinct longitudinal row of three caruncles.
The skin of metamorphosed free-living males is naked. There are two pairs of denticles on the lower denticular, the basal portion of the anterior pair is prolonged and directed anteriorly when the mouth is closed. The posterior pair is vertical and considerably shorter than the anterior. Caruncles are absent. Adult males are parasitic, the skin is spinulose, and the eyes are degenerate.
Females are dark red-brown to black over the entire surface of the body (except for the distal portion of the escal bulb) and oral cavity. The skin is unpigmented in juvenile males, but darkly pigmented in parasitic stages. Subdermal pigment is present, melanophores grouped as in the larvae.
The larvae are characterized by having a band of pigment on the posterolateral margin of the head, extending from the occipital region, continuing along the margin of the gill-cover and meeting anteriorly on the isthmus. Larger specimens have a lateral group of melanophores spreading from the base of the anal fin and becoming continuous with a dorsal group of melanophores. There is an isolated group of melanophores on the caudal peduncle. The peritoneum is pigmented dorsally.
Females attain a standard length of at least 358 mm. The largest known free-living male measures 10.5 mm, while parasitic males range from 8.0–99 mm.
The genus Cryptopsaras, and the only known species, C. couesii, differs from Ceratias, the only other recognized genus of the family, in having eight caudal-fin rays and a conspicuous spine on the anterodorsal margin of the subopercle.
Metamorphosed females of the genus are further distinguished from those of Ceratias in having a tiny illicium, reduced to a small remnant (nearly fully enveloped by tissue of the esca), and three club-shaped caruncles on the dorsal midline of the trunk just anterior to the origin of the soft-dorsal fin.
Metamorphosed males are further distinguished from those of Ceratias in having the anterior pair of lower denticular teeth considerably longer than the posterior pair.
Larvae, males, and juvenile females are unique in having subdermal pigment on the gill-cover, dorsal surface of trunk, and caudal peduncle.
The geographic distribution of C. couesii is similar to the combined ranges of Ceratias holboelli and C. uranoscopus, occurring in all three major oceans of the world between approximately 63°N and 43°S. It occurs throughout the North Atlantic, ranging as far north as Iceland and from the Gulf of Mexico to the African coast. In the South Atlantic, however, it appears to be restricted to the eastern side, ranging as far south as approximately 35°S off the tip of Africa. In the Pacific, C. couesii ranges from the Philippine and Molucca islands to the Eastern Tropical Pacific, and between Hokkaido, Japan, and Monterey Bay, California, to New Zealand and off northern Peru. In the Indian Ocean, this species is known from more than 60 specimens (primarily larvae and males), nearly all of which were taken at localities close to continental margins.
Meso- to bathypelegic. The apparent association with relatively shallow slope waters, however, is an artifact; in reality, the captures merely coincide with the route of the DANA Expedition of 1928–1930. Juvenile and adult females of C. couesii may be captured anywhere between approximately 75 and 4000 m. The majority of known specimens, however, were taken between 500 and 1250 m. Of the material for which depth of capture was known, 98% was taken by trawls that reached a maximum depth of 2000 m or less; 88% was collected by gear fished at 1250 m or less. At the upper end of its vertical range, 84% of the known material was taken at depths greater than 500 m. The average maximum depth for all known captures was 890 m.
Pietsch TW. 2009. Oceanic Anglerfishes: Extraordinary Diversity in the Deep Sea. Berkley: University of California Press. 638 p.
The genus Cryptopsaras, with a single species, is even better known, with more than 600 metamorphosed females, at least 100 free-living males, 74 parasitic males (attached to 46 females), and about 350 larvae. In contrast to those of Ceratias, the size ranges of free-living and attached Cryptopsaras males overlap slightly: the largest known free-living male measures 10.5 mm (14.3 mm TL), whereas known attached males range from 9.8 (attached to a 15.5-mm female) to 99 mm.
No free-living ceratiid male with large testes has ever been found, yet large ripe testes have been described in several attached males: those of three previously unreported UW specimens range from 7.3 mm to about 30 mm long (32.4–37.5% SL). Histological examination of the testes of two of these specimens (UW 21774, UW 21775; 20 and 34 mm, respectively), showed evidence of resorption, this indicating a recent spawning event. All known gravid females have a parasitic male attached. These data taken from both males and females reaffirm the idea that sexual maturity is never attained in members of this family unless stimulated by the attachment of a male.
The eyes of metamorphosed free-living males are unusually large in ceratiids, each having a prominent crescent-shaped aphakic space, but they quickly degenerate upon attachment to a female. The nostrils of ceratiid males, however, are minute, in marked contrast to those of all other ceratioids. The general assumption that pair formation in ceratioids is mediated by a species-specific pheromone emitted by the female and tracked by the male does not appear to apply to this family.
The denticular jaw apparatus of metamorphosed ceratiid males is well developed, consisting of a pair of upper and two pairs of lower teeth, each elongate and slightly hooked distally, appearing quite capable of nipping onto a female, but not especially well suited for prey capture. The alimentary canal is rather poorly developed. The few millimeters that the males increase in length during and after metamorphosis seem to result from a stretching of the body rather than any increase in body weight, and the liver decreases somewhat in size during this period. Thus, it appears that free-living metamorphosed males of this family do not eat.
Femle ceratiidas may become sexually parasitized at almost any size once past metamorphosis. Examples of small parasitized individuals include a 15.5-mm female, with a 9.8-mm male (USNM 234867); a 45-mm female, with a 10-mm male (ARC 8707665); and a 77-mm female, with a 15-mm male (BMNH 2004.6.29.4-5). In these three couples, the ovaries are as small as those found in non-parasitized females of a similar size, whereas the testes of the males are well developed, occupying more than half the volume of the coelomic cavity (1.7 mm long or 17% SL in ARC 8707665). Histological examination of the testes of the 10-mm male shows moderate resorption, thus indicating a recent spawning event. The members of the smallest attached pair appeared to be quite young, perhaps six months and certainly less than 12-months old.
The parasitic males of Ceratias are invariably attached to the belly of the female somewhat anterior to the anus; those of Cryptopsaras are usually found on the belly, most often off-set somewhat to the right or left, but may also be placed almost anywhere on the body. Although it is difficult to say in all cases, males more often than not attach themselves upside down with respect to the surface of the female and they are almost invariably directed anteriorly as if they approached their mate from behind.
Females to 358 mm SL, parasitic males to 99 mm SL, and free-living males to 10.5 mm SL.
ALBATROSS station 2101, Western North Atlantic, northwest of Bermuda, 38°18'N, 68°24'W, 0–3085 m, 3 October 1883.
Holotype of Cryptopsaras couesii: USNM 33558, 30 mm.
Cryptopsaras couesii is one of the most commonly collected ceratioid anglerfishes. The ceratioid anglerfishes are a group of 11 families with representatives distributed around the world below a depth of about 300 meters (they may sometimes be found at much shallower depths as well, e.g. see Cryptopsaras couesii in Stewart and Pietsch 1998). They are most strikingly characterized by having an extreme sexual dimorphism in which males are dwarfed and, in some species, become parasitically attached to the body of a relatively gigantic female. The males of most species (but not C. couesii or its sister taxon, Ceratias) are equipped with large nostrils, apparently for homing in on a female-emitted, species-specific pheromone (Pietsch 2005). Normal jaw teeth are lost during metamorphosis, but are replaced by a set of pincher-like denticles at the anterior tips of the jaws for grasping and holding fast to a prospective mate. In some forms (including Cryptopsaras couesii) attachment is followed by fusion of epidermal tissues and, eventually, by a uniting of the circulatory systems so that the male becomes dependent on the female for blood-transported nutriment, while the female becomes a sort of self-fertiliizing hermaphroditic host (Pietsch 1976; Pietsch and Orr 2007 and references therein). A Cryptopsaras couesii female may have as many as eight males attached to various parts of her body (Pietsch 2005). Attached C. couesii males are almost invariably found facing anteriorly, as if they approached their mates from behind (Pietsch 2005).
Most ceratioid anglerfishes, including Cryptopsaras couesii, have a bacterial bioluminescent bait or lure (known as an "esca"), the structure of which is extremely useful (at least to humans) in distinguishing species (Pietsch and Orr 2007). Remarkably, at least in C. couesii luminescence is not limited to the caruncle and esca. In shipboard experiments, Young and Roper (1977) found that this species is luminescent over most of its body, with the glow apparently emanating from its skin (except where damaged). In their experiments the fish varied its luminosity to match varying levels of overhead illumination, achieving both lateral and ventral countershading that made it nearly invisible.
See Pietsch (1986) for a technical diagnosis.
Cryptopsaras couesii has a wide distribution between 63°N and 54°S, although it appears to be absent from the western South Atlantic ocean (Stewart and Pietsch 1998).
Pietsch (1986) described the distribution as follows: Occurs in all three major oceans of the world [Atlantic, Pacific, and Indian Oceans] between approximately 63°N and 43°S. Throughout North Atlantic, ranging as far north as Iceland and from the Gulf of Mexico to the African coast. In the Pacific, ranges from the Philippine and Molucca Islands to the Eastern Tropical Pacific and between Hokkaido, Japan and Monterey Bay, California, to New Zealand and off northern Peru. In the Indian Ocean, this species is known from more than 60 specimens (primarily larvae and males) taken mainly from localities that appear to be associated with continental margins (but which in reality coincide with the route of the DANA Expedition of 1928-30).
Adolescents and adults of Cryptopsaras couesii have been captured between approximately 75 and 4000 m. The majority of known specimens, however, were taken between 500 and 1250 m (Pietsch 1986).
The ceratioid family Ceratiidae contains relatively elongate, large-sized anglerfishes, easily separated from members of allied families by having the cleft of the mouth vertical to strongly oblique, the posterior end of the pterygiophore of the illicium emerging from the dorsal midline of the trunk, and two or three caruncles on the back just anterior to the origin of the soft-dorsal fin (Pietsch 1986).
Cryptopsaras couesii: Dorsal fin rays 4 or 5; anal fin rays 4; pectoral fin rays 18; caudal fin rays 8. Female Cryptopsaras couesii have three fleshy, club-shaped caruncles on the dorsal midline of the trunk, just anterior to the origin of the soft dorsal fin, the central caruncle being the largest (Stewart and Pietsch 1998).
The sexual parasitic mode appears to be obligatory for Cryptopsaras couesii. Free-living males and non-parasitized females never have well-developed gonads. Thus, it appears males either establish a parasitic association with a female within the first few months of their lives and mature, or else die without mating (Pietsch 2005). The jaws and alimentary canals of free-living males appear unsuited for feeding themselves, so males probably do not feed after metamorphosis, instead depending on parasitic association with a female for long-term survival (Pietsch 2005). Given the dependence of both sexes on sexual parasitism for reproduction, it is surprising that of the more than 600 metamorphosed females in collections, only about 6% are parasitized (Pietsch 2005).
Cryptopsaras is a monotypic genus (i.e., it includes just a single species). Its closest known relatives are the three species of Ceratias (Pietsch and Orr 2007). Together, these two genera comprise the family Ceratiidae.
The ceratioid family Ceratiidae comprises two genera, Ceratias and Cryptopsaras, the former including three species and the latter just a single species (Pietsch 1986). Pietsch and Orr (2007) have reviewed the taxonomy and systematics of the ceratioid anglerfishes.
The triplewart seadevil (Cryptopsaras couesii) is a sea devil of the family Ceratiidae and the order Lophoiiformes.[1] This species is the only member of its genus.[1] Noted for its extreme sexual dimorphism, the triplewart seadevil's length ranges from 20 to 30 cm for females and 1 to 3 cm for males.[2]
Triplewart seadevils are ceratioids commonly found worldwide in all major oceans.[3] They are seen in depths ranging from 75 to 4000 m (250 to 13,100 ft), with the majority of specimens found in the mesopelagic and bathypelagic zones between 500 and 1250 m (1600 to 4100 ft).[3][4] It is dispersed from the deep ocean to shallower water because its weak swimming power allows it to be carried over long distances by ocean currents.[2]
Female triplewart seadevils have a laterally compressed, elongated body with a large head and a mouth that is nearly vertical when closed.[2][5] It has 2 to 3 rows of irregular depressible teeth, with significantly larger teeth on the lower jaw than the smaller upper jaw.[6] The body is covered by deeply embedded hollow spines. Only the tips show and there are no conical bone plates. The 3 lateral caruncles have club-shaped glands that secrete a slime containing luminous granules.[2] Adult females have jet-black pigmentation while juveniles are dark brown.[6] The triplewart seadevil uses an illicium, a modified dorsal spine on the snout, to lure prey. This apparatus is primarily composed of a terminating esca or lure supported by an extremely long pterygiophore bone encased in a dermal sheath.[3] Winding muscles control the anterior and posterior movement of the bone, suggesting extension and retraction by rotation.[3] The terminal esca contains bioluminescent bacterial symbionts, creating a glowing lure for their prey.[7][8][9]
The species displays extreme sexual dimorphism, where dwarfed males parasitize the larger females.[1] Their specialized jaw has an anterior pair of denticular teeth that are longer than their posterior pair.[10] Males permanently attach themselves to the ventral side of females with this specialized jaw meant for grasping a female mate.[2] Once attached, tissue fusion occurs, permanently binding the mouth and one side of the male to the surface of the female. After attachment, the male becomes dependent on the female for blood-circulated nutrients due to the fusion of the circulatory and digestive systems.[1] This case of extreme sexual dimorphism is favored by natural selection due to the random dispersal of individuals. If one of the relatively numerous males is fortunate enough to encounter a female, it attaches for the remainder of its life. This significantly increases the chance of reproduction for the individual and therefore increases its fitness.[1]
Female triplewart seadevils are receptive to parasitic males at a young age.[1] Once past metamorphosis, sexual parasitism may occur at almost any size (as small as 15 mm.) Despite this, the percentage of reproducing individuals is small. Of 600 metamorphosed females studied, only 6.2% were parasitized.[1] Spawning events occur more than once a year, and the Atlantic Ocean contains triplewart seadevil larvae for most of the year, with summer having the greatest occurrences.[2] The seadevil's method of sexual parasitism leads to the female to be akin to a self-fertilizing hermaphrodite. This is due to the nature of tissue fusion between mates and the continuous production of sperm by the male.[2] Unlike all other ceratioids, males do not have large nostrils for tracking species-specific pheromones emitted by the female. Instead, they have large eyes that degenerate upon attachment to the female.[1]
The triplewart seadevil (Cryptopsaras couesii) is a sea devil of the family Ceratiidae and the order Lophoiiformes. This species is the only member of its genus. Noted for its extreme sexual dimorphism, the triplewart seadevil's length ranges from 20 to 30 cm for females and 1 to 3 cm for males.
