Caulophrynidae

Introduction

The family Caulophrynidae includes globose bathypelagic anglerfishes, the females of which are easily distinguished from those of allied families by the absence of an expanded escal bulb, the presence of only two pectoral radials, extremely long dorsal- and anal-fin rays, only eight caudal-fin rays, and neuromasts of the acoustico-lateralis system located at the tips of elongate filaments. Two genera and five species are recognized. The family is nearly wordwide in distribution; however, individual species are so rare that full and true ranges are unknown.

Characteristics

Diagnosis

Metamorphosed females of the family Caulophrynidae are distinguished from those of all other ceratioid families by having extremely long dorsal- and anal-fin rays (greater than 60% SL); only eight caudal-fin rays; opercle, subopercle, posttemporal, and ventral portion of cleithrum greatly reduced; only two pectoral radials, ventralmost radial broadly expanded; neuromasts of acoustico-lateralis system located at tips of extremely elongate filaments; and illicium without an expanded escal bulb.

Metamorphosed females are further differentiated by having the following combination of character states: supraethmoid present; frontals without ventromedial extensions, meeting on the midline anterior to supraoccipital; parietals present, displaced anteriorly; sphenotic spines present; pterosphenoid absent; metapterygoid and mesopterygoid present; hyomandibular with a double head; hypohyals 2; branchiostegal rays 6 (2 + 4), rarely 5 (1 + 4); opercle bifurcate, very much reduced; subopercle long and narrow, reduced, with posterior margin deeply notched, ventral part without spine or projection on anterior margin; quadrate and articular spines rudimentary; angular and preopercular spines absent; jaws equal anteriorly; lower jaw with symphysial spine; postmaxillary process of premaxilla absent; maxillae reduced; anterior-maxillomandibular ligament absent; pharyngobranchials I and IV absent; pharyngobranchials II and III well developed and toothed; ossified hypobranchials and basibranchials absent; epibranchial and ceratobranchial teeth absent; epibranchial I and full length of ceratobranchial I free, not bound to wall of pharynx by connective tissue; distal one-third of ceratobranchial I bound by connective tissue to adjacent ceratobranchial II; proximal one-quarter to one-half of ceratobranchials II-IV not bound together by connective tissue; a single reduced epural; posterior margin of hypural plate notched in some specimens; pterygiophore of illicium bearing a small ossified remnant of second cephalic spine; escal bulb and central lumen absent; esca without large tooth-like denticles; coracoid with a well-developed posteroventral process; pectoral radials 2; pelvic bones cylindrical, without distal expansion; dorsal-fin rays 6-22 (6 in Robia, 14-22 in Caulophryne); anal-fin rays 5-19 (5 in Robia, 12-19 in Caulophryne); pectoral-fin rays 14-19; pelvic fins absent (but present in larvae and early metamorphic stages; see below); caudal-fin rays 8 (2 simple + 4 bifurcated + 2 simple); skin everywhere naked, dermal spinules absent; ovaries paired; two short pyloric caeca.

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Parasitic males of the family Caulophrynidae. A Caulophryne sp., 12 mm, attached to a 98-mm female, LACM 36025-1 (after Pietsch, 1979); B Caulophryne polynema, 15 mm, parasitically attached to a 137-mm female, MNHN2001-140. © 2005 Theodore W. Pietsch

Males, known from only five specimens, all assigned to Caulophryne (two free-living and three parasitically attached to females), with eyes large, a conspicuous aphakic space anterior to lens; olfactory organs large, nostrils directed laterally in smaller specimen, anterior nostrils close-set and directed anteriorly in larger specimen; jaw teeth absent; upper denticular with a dorsally directed tapering prolongation and bearing an irregular series of teeth along ventral margin; lower denticular with three lobes bearing 5, 8, and 5 teeth respectively; pectoral fins large, length about 40% SL; pelvic fins well developed in young free-living stages, lost with growth in later stages, including parasitic adults; fin-ray counts as given for metamorphosed females; skin naked; parasitic, but probably facultative (Pietsch, 2005).

Larvae, represented by 16 specimens, all assigned to Caulophryne, with body short; skin highly inflated; pectoral fins unusually large, reaching beyond dorsal and anal fins; pelvic fins well developed, with 3-4 rays (lost during metamorphosis); sexual dimorphism apparently absent, all known specimens with rudiment of illicium protruding from anterodorsal margin of head; fin-ray counts as given for metamorphosed females; metamorphosis beginning at lengths of 8-10 mm SL (Bertelsen, 1951:35, fig. 11A-B; 1984:326, 328, fig. 167A).

Description

Metamorphosed females with body short, globular, depth approximately 40-45% SL; mouth large, opening horizontal to slightly oblique; lower jaw of most specimens extending posteriorly beyond base of pectoral-fin lobe; oral valve well developed, lining inside of both upper and lower jaws; two nostrils on each side situated at the end of a single short tube; teeth slender, recurved, and depressible, those in lower jaw less numerous but slightly longer than those in upper jaw; number of teeth in upper jaw 20-45, in lower jaw 12-34; total number of vomerine teeth 1-5; epibranchial I free from wall of pharynx; epibranchials I-IV closely bound together; distal one-third of ceratobranchial I bound to ceratobranchial II, proximal two-thirds free; epibranchial IV and ceratobranchial IV bound to wall of pharynx, no opening behind fourth arch; gill filaments absent on epibranchials, present on proximalmost tip of ceratobranchial I and full length of ceratobranchials II-IV; pseudobranch absent; length of illicium highly variable, 16-125.8% SL (Caulophryne), 268.3% SL (Robia); anteriormost tip of pterygiophore of illicium exposed, emerging on snout, posterior end concealed beneath skin; escal bulb and central lumen absent; esca unpigmented and somewhat translucent, morphology simple, without elaborate filaments or appendages (Robia), or consisting of several branched appendages or numerous filaments (Caulophryne); some species with entire length of illicium covered with translucent filaments; neuromasts of acoustico-lateralis system located at tips of elongate cutaneous filaments, pattern of placement as described for other ceratioids (Pietsch, 1969, 1972, 1974a, 1974b).

Free-living males, only two known specimens, both assigned to Caulophryne: a 7.5-mm SL male in early metamorphosis, with skin naked, pelvic fins well developed (each with 4 rays), jaw teeth absent, upper denticular absent, lower denticular with two transverse series of teeth, eyes large with a conspicuous aphakic space anterior to lens, olfactory organs large, nostrils directed laterally (Bertelsen, 1951:310); an 11-mm SL male in metamorphosis, with skin naked, pelvic fins absent (lost with growth), jaw teeth absent, upper denticular with a dorsally directed tapering prolongation and bearing an irregular series of teeth along ventral margin, lower denticular with three lobes bearing 5, 8, and 5 teeth respectively, olfactory organs large, anterior nostrils close-set and directed anteriorly. Dorsal- and anal-fin ray counts undetermined; pectoral-fin rays 17; caudal-fin rays 8 (2 simple + 4 bifurcated + 2 simple).

Parasitic males, only three known specimens, 12-16 mm SL, all assigned to Caulophryne, with skin naked, olfactory organs degenerate; dorsal-fin rays 19-21; anal-fin rays 16-17; pectoral-fin rays 17; pelvic fins absent; caudal-fin rays 8 (2 simple + 4 bifurcated + 2 simple) (Regan, 1930b:191; Bertelsen, 1951:31; Pietsch, 1979:20).

Larvae, 16 known specimens, 3.7-11 mm TL, all assigned to Caulophryne, with body short; snout short, only about 10% of SL; skin highly inflated; eye unusually large, diameter 17% SL in smallest specimens to 13-14% SL in largest specimens; nostrils unusually large, longest dimension about one-half diameter of eye; dorsal-fin rays 11-20, anal-fin rays 11-17 (posteriormost rays of unpaired fins nearly impossible to distinguish without alizarin staining); pectoral fins large, reaching to base of caudal fin and well beyond dorsal and anal fins, each with 15-18 rays; pelvic fins long and well developed, each with 3 or 4 rays, reduced in early metamorphosis, lost in adolescents and adults; caudal-fin rays 8 (2 simple + 4 bifurcated + 2 simple) (Bertelsen, 1951:31, 35).

Color of preserved females dark brown to black over entire surface of head, body, fins (except for the esca, and the illicium of some species), and oral cavity; viscera unpigmented. Skin of parasitic, and free-living males in metamorphosis, lightly pigmented.

The largest known female is a 183-mm SL specimen of C. pelagica collected in the Atlantic off the Cape Verde Islands. The two known free-living males, both in metamorphosis, measure 7.7 and 11 mm SL. The three known parasitic males—one attached to the 142-mm holotype of C. polynema (see Regan, 1930), another to a 137-mm specimen of C. polynema, and the third attached to a 98-mm female identified by Pietsch (1979:18) as Caulophryne sp.—measure 16, 15, and 12 mm SL, respectively.

Distribution

Like most all ceratioid families, the Caulophrynidae is nearly worldwide in geographic distribution, but the individual species are so rare that full and true ranges are unknown. The distributions of the subtaxa of the family are made more complex by the existence of several specimens that probably represent undescribed species. Of the identified material, Caulophryne pelagica is known from only 11 females, one collected in the Atlantic off the Cape Verde Islands, the remaining 10 specimens widely distributed throughout the Indo-Pacific; Caulophryne bacescui is represented by a single female taken off Peru; Caulophryne jordani, 29 females from widely scattered stations in all three major oceans of the world; and Caulophryne polynema, 12 females, seven collected in the eastern Atlantic and five in the eastern North Pacific. Robia legula is known from a single female specimen collected in the Banda Sea.

Key to the Females of Genera of the Family Caulophrynidae

1B. Dorsal-fin rays 6; anal-fin rays 5; illicium long, 268% SL in only known specimen (Robia Pietsch, 1979)

Other Names for Caulophrynidae

• Fanfin Seadevils

References

Bertelsen, E. 1951. The ceratioid fishes. Ontogeny, taxonomy, distribution and biology. Dana Rept., 39, 276 pp.

Bertelsen, E. 1984. Ceratioidei: Development and relationships. pp. 325-334, In: Moser, H. G., W. J. Richards, D. M. Cohen, M. P. Fahay, A. W. Kendall, Jr., and S. L. Richardson (editors), Ontogeny and Systematics of Fishes, Spec. Publ. No. 1, Amer. Soc. Ichthy. Herpet., ix + 760 pp.

Goode, G. B., and T. H. Bean. 1896. Oceanic ichthyology, a treatise on the deep-sea and pelagic fishes of the world, based chiefly upon the collections made by the steamers Blake, Albatross, and Fish Hawk in the northwestern Atlantic. U. S. Nat. Mus., Spec. Bull., 2: 1-553.

Pietsch, T. W. 1969. A remarkable new genus and species of deep-sea anglerfish (family Oneirodidae) from off Guadalupe Island, Mexico. Copeia, 1969(2): 365-369.

Pietsch, T. W. 1972. A second specimen of the deep-sea anglerfish, Phyllorhinichthys micractis (family Oneirodidae), with a histological description of the snout flaps. Copeia, 1972(2): 335-340.

Pietsch, T. W. 1974a. Osteology and relationships of ceratioid anglerfishes of the family Oneirodidae, with a review of the genus Oneirodes Lütken. Nat. Hist. Mus. L. A. Co., Sci. Bull., 18, 113 pp.

Pietsch, T. W. 1974b. Systematics and distribution of ceratioid anglerfishes of the genus Lophodolos (family Oneirodidae). Breviora, 425: 1-19.

Pietsch, T. W. 1979. Ceratioid anglerfishes of the family Caulophrynidae, with the description of a new genus and species from the Banda Sea. Contrib. Sci., Nat. Hist. Mus. Los Angeles Co., 310: 1-25.

Pietsch, T. W. 2005. Dimorphism, parasitism, and sex revisited: modes of reproduction among deep-sea ceratioid anglerfishes (Teleostei: Lophiiformes). Ichthyol. Res., 52: 207-236.

Regan, C. T. 1930. A ceratioid fish (Caulophryne polynema, sp. n.), female with male, from off Madeira. J. Linn. Soc., London, 37: 191-195.