Osteology of the prowfish, Zaprora silenus (Cottiformes: Zoarcoidei: Zaproridae)

Abstract

The prowfish, Zaprora silenus, is the sole member of the family Zaproridae. It is a large, relatively elongate species with a robust head and body, and it feeds primarily on jellyfishes. Although the larvae and juveniles are pelagic, the adults are demersal, and the species is widely distributed from Southern California around the Pacific Rim to Hokkaido, Japan. The stichaeid affinities of this species have long been recognized, and the family is currently placed, along with the Stichaeidae, in the Zoarcoidei. Previous anatomical studies of Zaprora have been based on relatively few specimens from a limited geographic range and have not included cleared and stained (c&s) specimens. Here, we provide a complete description of the osteology of the prowfish, based on a large series of specimens representing a broad ontogenetic range, including a series of c&s specimens. Our results contradict the findings of previous authors in the structure of the pharyngeal teeth, presence of the pelvic girdle, and the placement of the first dorsal pterygiophore. However, we concur with the findings of previous morphological and molecular phylogenetic studies, which indicate that the prowfish is probably most closely related to at least some members of the Stichaeidae.

Osteology and ontogeny of the wrymouths, genusCryptacanthodes(Cottiformes:Zoarcoidei:Cryptacanthodidae)

“…Watson () and Matarese et al () considered having the dorsal fin composed only of spines present in the early postflexion stage to be a distinguishing character for larval stichaeids within zoarcoids, and note that this character is otherwise found only in pholids. De Forest et al () lists that in cryptacanthodids as well as in Zaprora silenus the dorsal fin is only composed of spines (see also Hilton and Stevenson, ). Our own observations show that these fin spines are present in a juvenile specimen of C. aleutensis (28.6 mm) and develop from paired elements ( C. aleutensis : 19 mm; still paired at the base, but with fused tips in a 36 mm specimen of C. maculatus ).…”

“…In Anarhichadidae, Zoarcidae, and Cryptacanthodidae, the anteriormost branchiostegals (three in Anarhichadidae and two in Zoarcidae and Cryptacanthodidae) articulate with the anterior ceratohyal on its medial side, whereas the following four articulate with the lateral side of the anterior and posterior ceratohyal (Barsukov, ; Anderson, : this character is shown in his illustrations, but not discussed). According to Makushok (), all branchiostegals attach to the lateral side of the ceratohyals in stichaeids, pholids, and ptilichthyids, whereas the anterior two branchiostegals contact the ventral margin of the anterior ceratohyal in deep recesses in bathymasterids, Zaprora silenus , and Scytalina cerdale (Matarese, ; Hilton, ; Hilton and Stevenson, ). The distribution of this character, however, must be further investigated, as the anterior branchiostegals are associated with deep recesses on the ventral margin of the anterior ceratohyal in at least some stichaeids (e.g., Xiphister , Clardy and Hilton, unpublished data).…”

“…(Figs. and ), Zaprora silenus (Zaproridae; Hilton and Stevenson, : Fig. ) and Anarhichas orientalis (Okiyama, :768) have a distinct white caudal region.…”

Osteology of Ronquilus jordani (Zoarcoidei: Bathymasteridae), with a discussion of the developmental osteology and systematics of bathymasterid fishes

“…The goals of this study are to provide a description of the skeleton of Ronquilus jordani (Figure ) to serve as a baseline contribution for systematic comparisons among all bathymasterid taxa and zoarcoids generally. This is intended to complement a series of studies describing the skeletal anatomy of zoarcoid families (Ptilichthyidae, Hilton & Kley, ; Scytalinidae, Hilton, ; Zaproridae, Hilton & Stevenson, ; Cryptacanthodidae, Schnell & Hilton, ; Stichaeidae [ Xiphister ], Clardy & Hilton, ; and Pholidae, Sweetser & Hilton, ). For information on the colour patterns, external anatomy (including pore patterns), and morphometric and meristic data for the family, see Stevenson and Matarese ().…”

Osteology of the crescent gunnel Pholis laeta and the phylogeny of the family Pholidae (Cottiformes, Zoarcoidei)

“…The osteological description given here is used as the basis for a preliminary systematic analysis of the family, with the goal of identifying characters defining the genera of Pholidae. A comprehensive analysis of the relationships within the genera and of the position of Pholidae within Zoarcoidei, however, are beyond the scope of this study and require further study of other pholid species and zoarcoid families (Anderson, ; Hilton & Kley, ; Hilton, ; Hilton & Stevenson, ; Schnell & Hilton, ; Clardy & Hilton, ).…”