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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.
