Interrelationships of Aulopiformes

In 1973, Rosen erected the order Aulopiformes for all non-ctenosquamate eurypterygians, that is, the Iniomi of Gosline et al. (1966) minus the Myctophiformes (Myctophidae and Neoscopelidae). Rosen's aulopiforms included 15 families (Alepisauridae, Anotopteridae, Aulopidae, Bathysauridae, Bathypteroidae, Chlorophthalmidae, Evermannellidae, Giganturidae, Harpadontidae, Ipnopidae, Omosudidae, Paralepididae, Scopelarchidae, Scopelosauridae, and Synodontidae) and 17 fossil genera, a morphologically diverse gro^u^p of benthic and pelagic fishes that range in habitat from estuaries to the abyss. Rosen (1973) diagnosed the Aulopiformes by the presence of. an elongate uncinate process on the second epibranchial (EB2) bridging the gap between a posterolaterally displaced second pharyngobranchial (PB2) and the third pharyngobranchial (PB3). He noted that paralepidid fishes lack this distinctive configuration of EB2 and thus questioned their placement in the order. Subsequently, R. K. Johnson (1982) recognized that certain paralepidids (Paralepis, and Notolepis) have an enlarged EB2 uncinate process but questioned Rosen's use of this feature to diagnose aulopiforms because he believed the same condition occurs in neoscopelids. Instead he suggested that the modification is a primitive iniome condition and that the small EB2 uncinate process of myctophids is secondarily derived. R. K. Johnson (1982) resurrected a more traditional view of iniome relationships in which Rosen's (1973) aulopiforms and myctophiforms are united in the order Myctophiformes. In 1985, Rosen altered his concept of a monophyletic Aulopiformes, noting that Aulopus shares several derived features with ctenosquamates, most notably a median rostral cartilage. Hartel and Stiassny (1986) considered a true median rostral cartilage a character of acanthomorphs and concluded that the morphology of the rostral cartilage is highly variable below that level. Nevertheless, Stiassny (1986) supported Rosen's (1985) view of a paraphyletic Aulopiformes, proposing that Chlorophthalmus, Parasudis and Aulopus form the sister group of ctenosquamates based on an elevated, reoriented cranial condyle on the maxilla and concurrent exposure of a "maxillary saddle" for reception of the palatine prong. G.D. Johnson (1992) discussed the shortcomings of Rosen's (1985) analysis and observed that neither Rosen nor Stiassny (1986) mentioned the distinctive gill-arch configuration originally described by Rosen (1973) as unique to aulopiforms. He added an additional gill-arch character to Rosen's (1973) complex, the absence of a cartilaginous condyle on PB3 for articulation of EB2, and concluded that a suite of gill-arch modifications constitutes a complex specialization supporting the monophyly of Rosen's (1973) Aulopiformes. In addition, Johnson (1992) offered further evidence (absence of the fifth upper pharyngeal toothplate and associated third internal levator muscle) for the monophyly of Rosen's (1973) Ctenosquamata, which include myctophids, neoscopelids and acanthomorphs, but not aulopi-