The Oneirodidae is by far the largest, most complex, and certainly the least understood family of the suborder. With 16 genera and 62 species, it contains nearly 40% of all recognized ceratioids. Of the 16 genera, five are currently represented by only one, two, or three adolescent or adult females; only eight are represented by more than a dozen females. Males have been described for only seven genera, while larvae are known for only eight. But despite the rareness of most recognized taxa, new oneirodids are continually being described.
Metamorphosed females of the family Oneirodidae are distinguished from those of all other ceratioid families by having the following combination of character states: supraethmoid present; frontals widely separated; parietals present; sphenotic overlapped by anterolateral projection of pterotic; metapterygoid and mesopterygoid present; hypohyals 2; branchiostegal rays 6 (2 + 4); angular and preopercular spines absent; jaws equal anteriorly; postmaxillary process of premaxillae absent; anterior-maxillomandibular ligament well developed; pharyngobranchial IV absent; a single ossified basibranchial; ceratobranchial teeth absent; epibranchial I free, not bound to wall of pharynx by connective tissue; proximal one-fourth to one-half of ceratobranchial I bound to wall of pharynx, distal three-quarters to one-half free; distal end of ceratobranchial I free, not bound by connective tissue to adjacent ceratobranchial II; proximal one-quarter to one-half of ceratobranchials II-IV not bound together by connective tissue; epurals absent; hypural plate entire, without posterior notch; pterygiophore of illicium bearing an ossified remnant of second cephalic spine; escal bulb and central lumen present, esca without tooth-like denticles; pectoral radials 3; dorsal-fin rays 4-8; anal-fin rays 4-7, very rarely 3; pectoral-fin rays 14-30; caudal-fin rays 9 (2 simple + 4 bifurcated + 3 simple); ovaries paired; one or two small pyloric caecae present or absent.
Although not characteristic of all members of the family, the following additional features are important in differentiating the Oneirodidae: each frontal with a prominent ventromedial extension (absent in Lophodolos); sphenotic spines usually present (absent in Chaenophryne); pterosphenoid usually present (absent in Lophodolos); hyomandibular usually with a double head (single head in Bertella); opercle bifurcate, dorsal fork supported by a single rib (except in larval females of Danaphryne); anterior subopercular spine usually absent (blunt projection present in most specimens of Chaenophryne, adolescent females of Lophodolos, and some larvae and males of Dolopichthys and Pentherichthys); quadrate and articular spines usually well developed (small to rudimentary in Chaenophryne); lower jaw usually with a well-developed symphysial spine (small, blunt to absent in Chaenophryne, absent in Pentherichthys); pharyngobranchial I usually absent (present in Spiniphryne and Oneirodes); pharyngobranchial II usually well developed and heavily toothed (reduced and toothless in Bertella, Microlophichthys, and some species of Oneirodes; absent in Pentherichthys and Lophodolos); epibranchial teeth usually absent (present on epibranchial I of some species of Oneirodes); ossified posteroventral process of coracoid usually absent (present in Spiniphryne and Oneirodes); pelvic bone usually rod-like, with or without slightly expanded distal tip (triradiate or broadly expanded distally in Chaenophryne; Pietsch, 1975:79, fig. 2); dermal spinules usually absent (well developed in Spiniphryne, minute and widely scattered in Oneirodes).
Free-living males of oneirodids. A Chaenophryne draco-group, 14 mm, ZMUC P92686; B Dolopichthys sp., 12.5 mm, ZMUC P92799; C Microlophichthys andracanthus, 16.5 mm, ZMUC P9293; D Oneirodes sp., 12.5 mm, ZMUC P921016; E Pentherichthys sp., 13 mm, ZMUC P921113. (All after Bertelsen, 1951, © 1951 Bertelsen).
Metamorphosed males are distinguished from those of all other ceratioid families in having the following combination of character states: eyes directed laterally, elliptical in shape, axis short, diameter of pupil greater than that of lens; olfactory organs large, anterior nostrils situated close together and opening forwards; posterior nostrils lateral, usually larger than eye; nasal area usually pigmented, sometimes slightly inflated; jaw teeth absent; dermal spinules of snout absent; posterior end of upper denticular remote from anterior end of pterygiophore of illicium; fin-ray counts as given for metamorphosed females; skin naked (but males of the spiny-skinned oneirodid genus Spiniphryne are unknown); free-living, non-parasitic, with two exceptions, both apparently facultative couplings: a single known attached pair of Leptacanthichthys gracilispinis and another of Bertella idiomorpha (see Pietsch, 2005).
There is no satisfactory combination of features that serve to adequately diagnose oneirodid larvae. As stated by Bertelsen (1951:71), it is “easier in practice to make the identification [of larvae] from the features characteristic of each of the many genera within the family.” To a somewhat lesser extent, the same could also be said for the metamorphosed males and females.
Metamorphosed females highly variable, ranging from short and deep-bodied, more-or-less globular (e.g., Oneirodes and Chaenophryne), to elongate and fusiform (e.g., Dolopichthys and Leptacanthichthys); head usually short, approximately 35% SL or less (30% SL in Dermatias, nearly 50% SL in some species of Chaenophryne); mouth large, opening horizontal to nearly vertical, cleft extending well past eye in most genera (terminating anterior to eye in Spiniphryne, Danaphryne, Phyllorhinichthys, Puck, Ctenochirichthys, and Bertella); jaw teeth slender, recurved, and depressible, those in upper jaw usually somewhat shorter and fewer than those in lower jaw (upper-jaw teeth more numerous than lower in Danaphryne, Microlophichthys, Tyrannophryne, Phyllorhinichthys, Puck, Leptacanthichthys, and Ctenochirichthys); number of premaxillary and dentary teeth highly variable, lower jaw with fewer than 20 (e.g., Phyllorhinichthys and some species of Oneirodes) to nearly 600 (e.g., some species of Dolopichthys); vomerine teeth usually present (lost with growth in Bertella and some species of Dolopichthys, absent in Lophodolos and Pentherichthys); epibranchial I free from wall of pharynx; epibranchials I-IV closely bound together; proximal one-fourth to one-half of ceratobranchial I bound to wall of pharynx, distal three-fourths to one-half free; epibranchial IV and ceratobranchial IV bound to wall of pharynx, no opening behind fourth arch; gill filaments present on proximal tips of epibranchials II-IV, on proximal tip of ceratobranchial I, and full length of ceratobranchials II-IV; pseudobranch absent; length of illicium highly variable, extremely short and nearly fully enveloped by tissue of esca (e.g., Tyrannophryne) to 75% SL (e.g., some species of Oneirodes and Dolopichthys); anteriormost tip of pterygiophore of illicium usually exposed (hidden in Tyrannophryne), emerging at tip of snout from between eyes or more posteriorly; posterior end of pterygiophore usually concealed under skin (protruding on dorsal surface of trunk behind head in Oneirodes); escal bulb simple to highly complex; neuromasts of acoustico-lateralis system located at tips of low rounded cutaneous papillae, pattern of placement as described for other ceratioids (Pietsch, 1969, 1972, 1974a, 1974b).
Color of females in preservative dark brown to black over entire external surface of body (except for escal appendages and distal portion of escal bulb); oral cavity and viscera, except for outer surface of stomach wall, unpigmented. Metamorphosed males with outer pigmentation as for females, except nasal area often unpigmented; subdermal pigmentation of males and larvae highly variable (see Bertelsen, 1951:73).
The largest known female is a 370-mm specimen of Oneirodes heteronema, collected by the Walther Herwig during the 1982 expedition to the mid-Atlantic Ridge. The largest known male measures 16.5 mm.
The Oneirodidae is widely distributed throughout the more productive waters of all three major oceans of the world. Unlike some ceratioid families (e.g., Melanocetidae), which appear to be limited by the Arctic and Antarctic Polar Fronts, oneirodids extend northward to at least 66º in the North Atlantic and 62º in the Bering Sea, and southward into the Southern Ocean to at least 65ºS. It is represented in the Caribbean Sea and in the gulfs of Aden, California, and Mexico; but, like all other ceratioids, it has not been collected in the Mediterranean Sea.
Molecular Biology and Genetics
Statistics of barcoding coverage
Specimens with Sequences:59
Specimens with Barcodes:56
Species With Barcodes:19
The dreamers are a family, Oneirodidae, of deep-sea anglerfishes in the order Lophiiformes. They are the largest and most diverse group of deep-sea anglerfish, and also the least well-known with several genera represented by only one, two, or three female specimens. They are found in deep, temperate waters around the world. They are small fishes, the largest species growing to about 20 cm (7.9 in) in total length.
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