click for previous page Ophidiiform Fishes of the World 1 1. INTRODUCTION hepurposesofthiscataloguearetopro- Although most of the research on ophidiiform Tvide a convenient means for the identifica- fishes over the past 2 decades has been con- tion of ophidiiform genera, and species to the cerned with distinguishing species and other extent possible, which are most likely to be taxa from each other, several ichthyologists encountered by fishery workers, ecologists have attempted to discover a classification and other marine biologists, to summarize fish- based on phyletic relationships for all or parts of eries, distributional and other biological infor- the order. The order Ophidiiformes was identi- mation, to guide users to the most relevant fied by Cohen and Nielsen (1978) using a com- literature, and to illustrate the wide diversity of bination of characters. One or more specialized this important group of fishes. Many ophidii- characters shared by all presumed ophidiiforms form species are abundant in nature and play have yet to be discovered. a significant role in the ecology of their habi- tats, but their identification often presents such In a search for uniquely ophidiiform characters great difficulty that they are referred to family Rosen (1985) implied that the order is not mo- or genus level only. nophyletic because of marked differences be- tween, and absence of specialized similarities This catalogue includes keys to and accounts among, the 2 suborders: Ophidioidei and Bythi- of all genera of ophidiiform fishes as well as toidei. Patterson and Rosen (1989) placed the lists of referred species and keys to most of 2 groups as adjacent but separate clades or them. Because many ophidiiforms are fishes of evolutionary lines. A survey of 36 genera (out of the deep sea, are rare in collections and have about 93) for a suite of osteological, myological, a relatively small and often imprecise litera- and cranial nerve characters failed to provide ture, keys to species of all genera are not Howes (1992) with data that would establish the possible. order as monophyletic. For present purposes, due to lack of anything better, we use the follow- Much of the information here included has ing definition of the order: been selectively compiled from the literature. Taxonomic descriptions have been verified to 1. Pelvic fins with 1 or 2 soft rays in each or fin the extent possible, using both preserved completely absent (in some species a basal museum and freshly caught specimens. This spine-like splint may be present). catalogue also constitutes an updating and 2. Pelvic fins inserted at about the level of the enlargement of Cohen and Nielsen (1978). It preopercle or farther anteriorly. does not purport to present a definitive phyletic classification of the order. 3. Pelvic fins bases close together (in all but Tauredophidium). 4. Dorsal and anal fins with long bases, ex- 1.1 General Remarks on the Order tending to and often joined with the caudal Ophidiiformes fin. A hierarchical classification that differed in sev- 5. Fin rays soft (except as noted above in eral respects from then current usage was no. 1). presented by Cohen and Nielsen (1978). They wrote that the purpose of their classification 6. Dorsal- and anal-fin pterygiophores more was chiefly to distinguish genera from each numerous than adjacent vertebrae. other and that it was not intended as a phylo- 7. Nostrils paired on each side of the head. geny. Although the relationships of various taxa were suggested, the problem of aligning Our presently used classification of the order taxa on the basis of synapomorphies (the pos- Ophidiiformes is shown in Fig. 1. session of shared special characters) received little explicit attention. 2 FAO Species Catalogue Vol. 18 ORDER SUBORDER FAMILY SUBFAMILY GENUS CARAPIDAE Carapus 4, Echiodon 11, Encheliophis 7, 7 genera Eurypleuron 1, Onuxodon 3, Pyramodon 4, 31 species Snyderidia 1 O O Brotulinae Brotula 5 P P H Brotulotaeniinae Brotulotaenia 4 I H D Cherublemma 1, Chilara 1, Genypterus 5, I Ophidiinae Lepophidium 15, Ophidion 21, Otophidium 4, I O Parophidion 2, Raneya 1 I OPHIDIIDAE D 48 genera Abyssobrotula 1, Acanthonus 1, Alcockia 1, D 218 species Apagesoma 2, Barathrites 2, Barathrodemus 2, E Bassogigas 1, Bassozetus 13, Bathyonus 3, I Benthocometes 1, Dannevigia 1, Dicrolene 15, I Enchelybrotula 2, Epetriodus 1, Eretmichthys 1, Glyptophidium 7, Holcomycteronus 6, Neobythitinae Homostolus 1, Hoplobrotula 3, Hypopleuron 1, I Lamprogrammus 5, Leptobrotula 1, Leucicorus 2, Luciobrotula 4, Mastigopterus 2, Monomitopus 14, Neobythites 35, Penopus 1, F Petrotyx 2, Porogadus 13, Pycnocraspedum 5, Selachophidium 1, Sirembo 3, Spectrunculus 1, Spottobrotula 2, Tauredophidium 1, O Typhlonus 1, Xyelacyba 1 Bellottia 2, Bythites 4, Calamopteryx 3, Cataetyx 11, Diplacanthopoma 8, R B Bythitinae Grammonus 6, Hastatobythites 1, Hephthocara 2, Microbrotula 2, Pseudonus 3, Saccogaster 8, Y BYTHITIDAE Stygnobrotula 1, Thalassobathia 2 M T 32 genera Beaglichthys 1, Bidenichthys 3, Brosmodorsalis H 96 species 1, Brosmolus 1, Brosmophyciops 1, I Brosmophycis 1, Brotulina 2, Dermatopsis 2, E Brosmophycinae T Dermatopsoides 2, Diancistrus 1, Dinematichthys 7, Dipulus 2, Fiordichthys 1, S O Gunterichthys 1, Lucifuga 6, Melodichthys 2, I Monothrix 2, Ogilbia 6, Parabrosmolus 1 D E APHYONIDAE I 6 genera Aphyonus 4, Barathronus 9, Meteoria 1, 22 species Nybelinella 2, Parasciadonus 2, Sciadonus 4 Fig. 1 Arrangement of Ophidiiformes followed in this catalogue. Entries under each taxonomic category are alphabetical. Figures in boldface refer to the number of species Ophidiiform Fishes of the World 3 1.2 General Remarks on Suborders and The subfamily Ophidiinae, containing the cusk- Families eels, is an apparently monophyletic group char- acterized in having the pelvic fins far forward The suborder Ophidioidei, as herein treated, and supported by an anterior extension of the was distinguished by Cohen and Nielsen pectoral girdle. The closest relative of the cusk- (1978) with a suite of characters that Gordon eels is not known, although Howes (1992) finds et al. (1984), Rosen (1985), Patterson and similarities with Brotula and several neo- Rosen (1989), and Howes (1992) found to be bythitine genera. There are 8 genera and about primitive, negative, or otherwise unsatisfactory 50 described and many undescribed species of for phylogenetic purposes. These authors cusk-eels which are found around the world in noted that although some of the constituent tropical, subtropical and temperate seas, mostly taxa or un-named clusters of genera posses on the continental shelf. Some of the common specialized characters, there is no presently species classified in the southern hemisphere known encompassing synapomorphy for the genus Genypterus grow large enough to sup- entire suborder. port fisheries. The family Carapidae is a monophyletic group The subfamily Neobythitinae contains 38 gen- of elongate fishes that have pelagic larvae with era and about 170 described species (many of a specialized first dorsal-fin ray called a vexil- which were formerly classified in an expanded lum. According to Howes (1992) the Carapidae family Brotulidae) and numerous undescribed is the closest relative of all other ophidiiform species. It does not at present meet the require- fishes. Carapids include 7 genera and about ments for monophyly (Howes, 1992). Further 30 species and are found around the world research is required to define several clusters from tropical reefs and warm-temperate shal- of genera and help decide whether they should low water to the continental slope. Many spe- remain in this subfamily. Although a single ge- cies live as adults inside of sea cucumbers and nus of neobythitines, Petrotyx, lives on tropical other large bottom dwelling invertebrate ani- reefs, most are found in deeper water, from the mals. continental shelf to a depth of 8 370 m where The family Ophidiidae as herein treated has Abyssobrotula galatheae, the deepest known not been shown to be monophyletic. It contains fish, has been caught. about 50 genera that we here subdivide into 4 The suborder Bythitoidei was distinguished by subfamilies. Cohen and Nielsen (1978) chiefly on the basis The subfamily Brotulinae, the brotulas, con- of viviparity and associated anatomical fea- sists of a single genus, Brotula,whichismost tures, which Patterson and Rosen (1989) con- obviously characterized by the possession of sidered as specialized. Thus the mantle of barbels on the snout and chin. Similarities of monophyly was bestowed on bythitoids. Brotula to the gadiform genus Muraenolepis The family Aphyonidae is a monophyletic group have been described by Markle (1989), and of fragile, scaleless, and mostly rare fishes with Howes (1992) found similarities between Bro- a high number of precaudal vertebrae and many tula and several neobythitine genera (an ex- neotenous features. The closest relative of panded family Brotulidae once contained Aphyonidae is the Bythitidae. Aphyonids include many genera now classified in other ophidii- 6 genera and 22 species and are found close to form groups). There are at least 5 species of the bottom in all oceans at depths ranging from Brotula, some of which are quite common, the continental shelf to the abyss. Nelson (1994) living at shallow to mid-depths in tropical and moved the Parabrotulidae from the Zoarcifor- subtropical waters around the world. mes to the Ophidiiformes as it might be a de- The subfamily Brotulotaeniinae is most obvi- rivative of the Aphyonidae. He based the ously characterized in having its scales modi- reassignment on M.E. Anderson’s remarks in fied into small prickles. Its closest relative is not Smith and Heemstra (1986) even though Smith known. There is a single genus, Brotulotaenia, and Heemstra kept the Parabrotulidae in the with 4 uncommonly encountered species Zoarciformes. Until more research has shown found in the meso- to bathypelagic of tropical the proper placement of the Parabrotulidae we and subtropical seas. exclude them from the Ophidiiformes. 4 FAO Species Catalogue Vol. 18 The family Bythitidae is considered a mono- are found in surface waters, often far from the phyletic group which is here divided into 2 shore.