Neoceratias spinifer

Introduction

The monotypic Neoceratiidae represents a lineage that has departed drastically from ceratioid morphology. Most notably, Neoceratias spinifer has lost the illicial apparatus that defines all other families in the suborder. Owing mostly to its rarity, nearly nothing is known about the biology of this species.

Characteristics

Diagnosis

Metamorphosed females of the Neoceratiidae are unique among ceratioid families in lacking an illicium and second cephalic spine, as well as the cranial trough within which the pterygiophore of the illicium lies in all other female ceratioids; frontals broad and rectangular in shape; metapterygoid and mesopterygoid absent; preopercle unusually short and nearly straight; premaxillae and dentaries unusually thick and well developed, with rounded edges; a pair of prominent nasal papillae on snout (nostrils and olfactory lamellae absent); jaws with a single inner row of small immobile teeth, outer margin of jaws bearing two or three series of long hinged teeth, each with a tiny distal hook; dorsal and anal fins mounted on prominent bases (Bertelsen, 1951:156-157, fig. 105).

Metamorphosed females are further differentiated by having the following combination of character states: supraethmoid present; frontals without ventromedial extensions, meeting on the midline; parietals present; sphenotics conical in shape, without spine; pterosphenoid present; hyomandibular with a single head; hypohyals 2; branchiostegal rays 6 (2 , 4), rarely 5 (1 , 4); opercle bifurcate, much reduced; subopercle reduced, long and narrow, as long as or slightly longer than lower fork of opercle, without posterior notch, ventral part without spine or projection on anterior margin; quadrate, articular, angular, and preopercular spines absent; jaws subequal, lower jaw extending anteriorly beyond upper; lower jaw without symphysial spine; postmaxillary process of premaxilla absent; anterior-maxillomandibular ligament absent; pharyngobranchials I, II, and IV absent; pharyngobranchial III well developed and toothed; a single ossified hypobranchial; ossified basibranchials absent; epibranchial and ceratobranchial teeth absent; epibranchial I free, not bound to wall of pharynx by connective tissue; proximal one-half of ceratobranchial I bound to wall of pharynx; 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 closely bound together by connective tissue, displacing gill filaments; epurals absent; posterior margin of hypural plate deeply notched; pterygiophore of illicium fully embedded in skin of head, without ossified remnants of illicium or second cephalic spine; esca absent; posteroventral process of coracoid absent; pectoral radials 3; pelvic bones small, cylindrical, without distal expansion; dorsal-fin rays 11-13; anal-fin rays 10-13; pectoral-fin rays 12-15; pelvic fins absent; caudal peduncle unusually long and slender, caudal fin of females very broad, with four innermost rays deeply bifurcated; caudal-fin rays 9 (2 unbranched , 4 branched , 3 unbranched), 10 caudal rays in some larvae (see Bertelsen, 1951:159, table 36); skin everywhere naked, dermal spinules absent; ovaries paired; two short pyloric caeca.

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Parasitic males of Neoceratias spinifer. A 15.5 mm attached to a 52-mm female, ZMUC P921726 (after Bertelsen, 1951); B 12.5 mm, attached to a 74-mm female, ISH 5546/79 (after Munk, 2000); C 18 mm, parasitically attached to a 108-mm female, SIO 70-336. © 2005 Theodore W. Pietsch

Free-living males unknown; parasitic males, seven known individuals (11.5-18 mm), differ from those of all other ceratioid families in having an unusually slender body; eyes and olfactory organs degenerate; jaws retaining a few short teeth on each side; premaxillae retained, apparently not reduced; upper denticular bone apparently absent; lower denticular bearing three elongate curved projections each bifurcating distally; pelvic fins absent; fin-ray counts as given for metamorphosed females; skin naked, without dermal spinules; parasitism apparently obligatory (Pietsch, 2005).

Larvae (eleven known specimens, 4-12.5 mm TL) differ from those of all other ceratioid families in having an elongate, slender body, depth 30-40% SL; length of head relatively shorter than those of other ceratioids, 30-40% SL; length of caudal fin 20-30% SL; skin only slighted inflated; pterygiophore of illicium well developed; all known specimens with an elongate cylindrical rudiment of illicium protruding (in a position unique among ceratioid larvae) on tip of snout, just above symphysis of upper jaw, sexual dimorphism apparently absent; pectoral fins relatively small, length 15-20% SL; pelvic fins absent; fin-ray counts as given for metamorphosed females; metamorphosis beginning at lengths of 8-10 mm SL (Bertelsen, 1951:159, fig. 106A-C; 1984:326, 328, fig. 167B).

Description

Metamorphosed females with body elongate, slender, slightly compressed, depth approximately 18-20% SL; head short, length approximately 27-30% SL; mouth large, cleft extending posteriorly well past eye, opening horizontal to slightly oblique; oral valve absent; eyes minute, appearing degenerate, diameter less than 2% SL; a pair of large nasal papillae on snout, length approximately 6% SL, unpigmented on distal end, nostrils and lamellae absent; jaws with an inner row of short, straight, widely spaced immobile teeth, 6 on each premaxilla and 10 on each dentary in 74-mm specimen; outer margins of jaws with prominent conical outgrowths, providing articular surfaces for two or three irregular series of long straight hinged teeth, strongly attached by connective tissue and well-developed musculature, and each with a tiny distal hook; outermost and posteriormost teeth largest, length of some nearly 15% SL; 16 or 17 teeth on each premaxilla and 18 on each dentary in 74-mm specimen; vomerine teeth long and slender, 1 on each side; pharyngobranchial III unusually large, well toothed (similar to that of Gigantactis in shape and relative size; see Bertelsen et al., 1981:11, figs. 13, 16); epibranchial I free from wall of pharynx; epibranchials I-IV closely bound together; proximal one-half of ceratobranchial I bound to wall of pharynx; proximal one-quarter of ceratobranchial II bound to ceratobranchial III; proximal one-half of ceratobranchial III bound to ceratobranchial IV; epibranchial IV and ceratobranchial IV bound to wall of pharynx, no opening behind fourth arch; gill filaments present on proximal ends of epibranchials II-IV, on proximal tip of ceratobranchial I, full length of ceratobranchial II, distal three-quarters of ceratobranchial III, and distal one-half of ceratobranchial IV; pseudobranch absent; head and body with numerous elongate filaments, undoubtedly bearing neuromasts of acoustico-lateralis system (not light organs as suggested by Koefoed, 1944:10).

Males, known only as parasites on females, with frontals relatively smaller and narrower than those of females; pterygiophore of illicium without trace of illicium or second cephalic spine; fin-rays counts, number of branchiostegal rays, and shape of hyomandibular and opercular bones comparable to those of females; premaxillae well developed (reduced in most other ceratioid males), each bearing two immobile teeth near symphysis; upper denticular bone absent; dentaries shorter, but somewhat broader than those of females, each bearing three small immobile teeth; lower denticular bone triradiate, each fork bifurcated distally to form a total of six short flattened denticles (Bertelsen, 1951:157-158, fig. 105B).

Bertelsen’s (1951:161, fig. 106-D-E, 107) description of a parasitic male attached to a 52-mm female applies well to all known specimens: body long and slender, depth 20% SL; length of head 26% SL; length of caudal rays about 23% SL; firmly attached to female by outgrowths from the lower jaw and snout; triradiate lower denticular bone firmly anchored in tissues of female; olfactory organs apparently absent; eyes degenerate, covered with weakly pigmented skin, appearing as a deeper lying irregular mass of pigment; liver relatively small, stomach and intestines undeveloped but not obviously degenerate; testes in development but not remarkably large.

Smallest known larva (3.7 mm SL) with body slender, tail straight, skin only slightly inflated; depth of body and length of head 35-40% SL; length of caudal fin 25-30% SL. Largest larva (9.8 mm SL) somewhat more slender; body depth and head length about 30% SL; length of caudal fin only about 20% SL; fin-ray counts, number of branchiostegal rays, and shape of hyomandibular, opercular, and pelvic bones comparable to those of metamorphosed specimens (Bertelsen, 1951:156, 160, fig. 106A-C, table 36). Pterygiophore of illicium rather well developed, but no indication of an ossified illicium; in two smallest specimens (3.7-4.0 mm SL), a small wart-like structure beneath skin at tip of pteriogphore of illicium; cylindrical and elongate in larger specimens, emerging immediately above symphysis of upper jaw, projecting dorsally on snout; diminishing in size in larger specimens, while overlying skin becomes increasingly more pigmented; no differences detected that might be interpreted as sexual dimorphism (see Bertelsen, 1951:159, 1984:328). Olfactory organs prominent, similar relative size in all known specimens; peritoneum unpigmented; body usually with conspicuous dorsal and ventral streaks of pigment, each several melanophores thick; pigmentation strongest between posterior bases of dorsal and anal fins (see Bertelsen, 1951:159, fig. 106A-C).

Color of preserved females dark red-brown to black over entire surface of head, body, fins, and oral cavity; viscera unpigmented; skin of parasitic males everywhere more lightly pigmented and semitransparent, allowing subdermal pigmentation to show through.

The largest known male, 18 mm SL, is parasitically attached to the largest known female, 108.5 mm SL, collected off Luzon, Philippine Islands.

Other Names for Neoceratias spinifer

• Neoceratiidae
• Needlebeard Seadevils

References

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

Bertelsen, E., T. W. Pietsch, and R. J. Lavenberg. 1981. Ceratioid anglerfishes of the family Gigantactinidae: Morphology, systematics, and distribution. Nat. Hist. Mus. L. A. Co., Contri. Sci., 332, vi + 74 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.

Koefoed, E. 1944. Pediculati from the "Michael Sars" North Atlantic Deep-sea Expedition 1910. Rept. Sci. Res. "Michael Sars" Exped. 4, 2(1): 1-18.

Munk, O. 2000. Histology of the fusion area between the parasitic male and the female in the deep-sea anglerfish Neoceratias spinifer Pappenheim, 1914 (Teleostei, Ceratioidei). Acta Zool., Stockholm, 81(4): 315?324.

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