Chimaeridae

Spotted ratfish Hydrolagus colliei, copyright Stosh Morency.

Belongs within: Chimaeriformes.

The Chimaeridae, shortnose chimaeras or ratfishes, are shark-like fishes with a large, blunt head and tapering bodies (Didier 2002a).

Characters (from Didier 2002a): Medium-sized shark-like fishes with large head, blunt snout, and somewhat compressed, elongate bodies, tail tapering to an elongate filament. Colour pale to dark brown, darker dorsally, lighter or white ventrally, usually without distinct colour pattern. Eyes large and prominent, bright green in fresh specimens. Snout fleshy and bluntly pointed at tip. Mouth small, ventral, connected to nostrils by deep grooves. Teeth in the form of three pairs of non-replaceable tooth plates with two pairs in the upper jaw, and one pair in the lower jaw. Tooth plates robust with patches of dense hypermineralised tissue that appear as ridges and bumps on the surface. Skin smooth, often deciduous, flaking off in patches after capture. Gills covered by a fleshy operculum with only a single gill opening present anterior to pectoral fins; no spiracle present. Two dorsal fins, the first erectile, preceded by an elongate, serrate spine, in some species toxic; the second elongate and spineless. Tail diphycercal with dorsal and ventral caudal-fin lobes of nearly equal size. Pectoral and pelvic fins broad with delicate external fin webs supported by cartilaginous rays (ceratotrichia). Lateral-line canals appear as open grooves on head and sides of body; canals on snout with large dilations. Adult males with bulbous, denticulate frontal tentaculum that rests in a pouch atop the head anterior to eyes; prepelvic tenaculae blade-like with large denticles along medial edge, hidden in pouches anterior to pectoral fins; and pelvic claspers bifurcate with fleshy, denticulate tips. In some species the fleshy lobes separate, appearing as a third division of the clasper, but not supported by an internal cartilaginous rod.

Chimaeridae
|--Similihariotta dabasinskasi Zangerl 1979CDZ93
|--Amylodon delheidiF91
|--ElasmodusCDZ93
| |--E. crassus (Hebert 1854)CDZ93
| |--E. greenoughi Agassiz 1843CDZ93
| |--E. planus Leriche 1929CDZ93
| `--E. ubaghsi Leriche 1929CDZ93
|--Chimaera Linnaeus 1758L58
| |--C. callorynchus Linnaeus 1758L58
| |--C. cubana Howell Rivero 1936D02a
| |--C. gosseletiF91
| |--C. lignaria Didier 2002D02b
| |--C. monstrosa Linnaeus 1758L58
| |--C. owstoniD98
| |--C. panthera Didier 1998D98
| `--C. phantasma Jordan & Snyder 1900DS02
`--HydrolagusDS02
|--H. affinis (Capello 1868)M02
|--H. alberti Bigelow & Schroeder 1951D02a
|--H. bemisi Didier 2002D02b
|--H. collieiB96
|--H. deani (Smith & Radcliffe 1912)C99
|--H. lemures (Whitley 1939)C99
|--H. mirabilis (Collett 1904)D02a
|--H. novaezealandiae (Fowler 1910)D02b
|--H. pallidus Hardy & Stehmann 1990DS02
`--H. trolli Didier & Séret 2002DS02

*Type species of generic name indicated

References

[B96] Bond, C. E. 1996. Biology of Fishes 2nd ed. Saunders College Publishing: Fort Worth.

[CDZ93] Cappetta, H., C. Duffin & J. Zidek. 1993. Chondrichthyes. In: Benton, M. J. (ed.) The Fossil Record 2 pp. 593–609. Chapman & Hall: London.

[C99] Compagno, L. J. V. 1999. Chimaeras. In: Carpenter, K. E., & V. H. Niem (eds) The Living Marine Resources of the Western Central Pacific vol. 3. Batoid fishes, chimaeras and bony fishes part 1 (Elopidae to Linophrynidae) pp. 1531–1537. FAO: Rome.

[D98] Didier, D. A. 1998. The leopard Chimaera, a new species of chimaeroid fish from New Zealand (Holocephali, Chimaeriformes, Chimaeridae). Ichthyological Research 45: 281–289.

[D02a] Didier, D. A. 2002a. Chimaeras. In: Carpenter, K. E. (ed.) The Living Marine Resources of the Western Central Atlantic vol. 1 pp. 591–599. Food and Agriculture Organization of the United Nations: Rome.

[D02b] Didier, D. A. 2002b. Two new species of chimaeroid fishes from the southwestern Pacific Ocean (Holocephali, Chimaeridae). Ichthyological Research 49: 299–306.

[DS02] Didier, D. A., & B. Séret. 2002. Chimaeroid fishes of New Caledonia with description of a new species of Hydrolagus (Chondrichthyes, Holocephali). Cybium 26 (3): 225–233.

[F91] Freess, W. B. 1991. Beiträge zur Kenntnis von Fauna und Flora des marinen Mitteloligozäns bei Leipzig. Altenburger Naturwissenschaftliche Forschungen 6: 3–74.

[L58] Linnaeus, C. 1758. Systema Naturae per Regna Tria Naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata. Laurentii Salvii: Holmiae.

[M02] McEachran, J. D. 2002. Shortnose chimaeras. Family Chimaeridae. In: Collette, B. B., & G. Klein-MacPhee (eds) Bigelow and Schroeder’s Fishes of the Gulf of Maine 3rd ed. pp. 22–23. Smithsonian Institute Press: Washington.

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