Dermatias platynogaster, the Bulbous Deep Sea Angler, is a deep-sea fish known from only three specimens , all females collected in the Western Pacific Ocean, with gear fished on the bottom: one off Luzon in the Philippines, taken with a beam trawl in relatively shallow water (549 m); the second in the vicinity of the Magellan Seamounts, east of the Mariana Islands, with a bottom trawl fished at a maximum depth of 1342 m; and the third in the vicinity of the Townsville Trough (Queensland, Australia), with a bottom trawl fished at a maximum depth of 1188 m (Kharin and Pietsch 2007). This species, the only species placed in the genus Dermatias, is distinguished from all other members of the family Oneirodidae by its unusually deep caudal peduncle, extremely short head, and remarkably small number of teeth in the jaws (Pietsch and Kharin 2004; Pietsch 2009). Like other anglerfishes, D. platynogaster have an escal appendage on the top of the head, which presumably functions as a bacterial bioluminescent lure, as in related species. Escal morphology is strikingly similar to that of some Oneirodes species (Pietsch and Kharin 2004).
The D. platynogaster that have been found have ranged between 134 and 175 mm in length (Pietsch 2009).
Dermatias platynogaster Smith and Radcliffe, in Radcliffe, 1912:206–207, pl. 17, fig. 3 (original description, single specimen). Pietsch and Kharin, 2004:123, 124, figs. 1, 3, 4 (resurrection from synonymy of Oneirodes eschrichtii). Kharin and Pietsch, 2007:806, figs. 1, 2 (additional specimen, off Queensland, Australia).
Dolopichthys platynogaster: Regan, 1926:29–30 (brief description after Smith and Radcliffe, in Radcliffe, 1912; in key). Bertelsen, 1951:79, 81 (one of 22 nominal species placed in the Oneirodes eschrichti-group). Pietsch, 1974a:44, 53, 102, table 9 (a synonym of Oneirodes eschrichtii).
Dolopichthys (subgenus Dermatias) platynogaster: Parr, 1927:14 (in key). Regan and Trewavas, 1932:68, fig. 95 (brief description after Smith and Radcliffe, in Radcliffe, 1912; in key
Pietschichthys horridus Kharin, 1989:158–160, figs. 1, 2 (original description, single specimen). Pietsch and Kharin, 2004:123, 125, figs. 2, 4 (a junior synonym of Dermatias platynogaster).
Metamorphosed females of D. platynogaster are distinguished from those of all other genera of the family in having an unusually deep caudal peduncle (21.6–23.8% SL); a blunt snout and short, highly convex frontals resulting in an extremely short head (29.7–30.5% SL); and remarkably few teeth in the jaws (20–32 in the upper jaw, 20–31 in the lower jaw).
Metamorphosed females of D. platynogaster are further unique in having the following combination of character states: Vomerine teeth are present. The sphenotic spines are well developed (their length 2.9–3.6% SL) and directed dorsolaterally. The lower jaw bears a stout symphysial spine. The hyomandibular has a double head. The quadrate spine is well developed (its length 2.5–5.0% SL), but the articular spine is less than one-half the length of the quadrate spine. The posterior margin of the opercle is deeply notched. The subopercle is long and narrow, its dorsal end tapering to a point (the posterior margin without indentation), its ventral end oval in shape (without an anterior spine or projection). The caudal-fin rays are without internal pigmentation. The illicium is considerably longer than the length of the esca bulb. The pterygiophore of the illicium emerges on the snout from between the frontal bones, its anterior end exposed, its posterior end concealed beneath the skin. The first ray of dorsal fin is well developed. There are 6 dorsal-fin rays and 4 anal-fin rays . The pectoral-fin lobe is short and broad (its length 6.6–8.9% SL), shorter than the longest rays of the pectoral fin (16.3–19.9% SL). There are 15–16 pectoral-fin rays. The skin is smooth and apparently naked, without dermal spinules (but specimens are unavailable for clearing and staining). Darkly pigmented skin of the caudal peduncle extends well past the base of the caudal fin (only three known specimens, 134–175 mm; material unavailable for internal osteological examination).
Albatross, Philippine Expedition, station 5463, near Sialat Point Light, off east coast of Luzon, Philippine Islands, Western North Pacific, 13º40'57"N, 123º57'45"E, beam trawl, 300 fathoms (549 m), 16 June 1909.
Holotype: USNM 70269, 134 mm, female.
Like many species of ceratioid anglerfishes, D. platynogaster is known from relatively few specimens (n=3) and thus, little is known about even the most basic aspect of this species' biology.
All three known specimens of Dermatias platynogaster were collected in the Western North Pacific Ocean, with gear fished on the bottom: one off Luzon in the Philippines taken with a beam trawl in relatively shallow water (549 m); another in the vicinity of the Magellan Seamounts, east of the Mariana Islands, with a bottom trawl fished at a maximum depth of 1342 m; and the third from the Townsville Trough, off Queensland, Australia, with a bottom trawl fished at 1188 m.
The body of metamorphosed females is moderately short, somewhat fusiform, its depth approximately 45–55% SL. The snout is blunt; the head extremely short (29.7–30.5% SL). The mouth is small, the opening almost horizontal, and the cleft extending slightly past the eye. The opercular opening is unusually large, 19.4–22.5% SL. The illicium length is 15.3–17.5% SL. The esca, remarkably similar to those of some species of Oneirodes, bears a stout, internally pigmented anterior escal appendage approximately as long as the length of the escal bulb; a pair of medial escal appendages, each consisting of a dense cluster of slender filaments, some slightly longer than length of the escal bulb, and each with a darkly pigmented distal tip; a small rounded terminal papilla, with a single terminal pigment spot; and a simple unpigmented filamentous posterior escal appendage somewhat longer than the length of the escal bulb.
The teeth in the jaws are slender, recurved, and all depressible, those in the lower jaw slightly larger than those of the upper jaw. The longest tooth in upper jaw measures 2.4–3.1% SL; the longest in lower jaw is 3.4–3.7% SL. There are 20–32 teeth in upper jaw and 20–31 in the lower jaw. There are 4–6 teeth on the vomer. The second and third pharyngobranchials are both well developed and toothed.
The following measurements are expressed in percent SL: head length 29.7–30.5; head width 25.5–29.1; head depth 33.7–36.6; least outside width between frontals 9.1–10.9; length of premaxilla 22.4–24.0; length of lower jaw 25.2–33.6; length of lower fork of opercle 19.7–22.5, upper fork 10.9–14.9; length of subopercle 8.6–11.3.
Known from only three metamorphosed females, 134–175 mm standard length.
Metamorphosed females of D. platynogaster, the only species of the genus Dermatias, are distinguished from those of all other genera of the family in having an unusually deep caudal peduncle (21.6–23.8% SL); a blunt snout and short, highly convex frontals resulting in an extremely short head (29.7–30.5% SL); and remarkably few teeth in the jaws (20–32 in the upper jaw, 20–31 in the lower jaw).
Catalog Number: USNM 70269
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Fishes
Preparation: Radiograph; Photograph; Illustration
Year Collected: 1909
Locality: Sialat Point Light, South 74 degrees East, 3.9 miles, Luzon, Philippines, Pacific
Depth (m): 549 to 549
As with nearly all species of deep-sea anglerfishes, D. platynogaster lures prey to its mouth with bioluminescence emitted from the esca. Unlike most deep-sea fishes that produce bioluminescence, light produced by ceratioid anglerfishes is not endogenous, but rather the product of a bacterial community in the esca.
Life History and Behavior
Although males are unknown, D. platynogaster is probably like many species of the family Oneirodidae in that they never become parasitic. Spawning and fertilization may take place during a temporary sexual attachment that does not involve fusion of male and female tissues.
Dermatias platynogaster is a species of dreamer (type of deep-sea anglerfish) found in the western Pacific Ocean where it occurs at depths of 549 to 1,342 metres (1,801 to 4,403 ft) in the waters around the Philippines and in the area of the Magellan Seamounts. The females of this species grow to a length of 15.6 centimetres (6.1 in). This species is the only known member of its genus.
- Froese, Rainer and Pauly, Daniel, eds. (2012). "Dermatias platynogaster" in FishBase. April 2012 version.
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