The intermuscular bones and ligaments of teleostean fishes

Abstract

Patterson, Colin, and G. David Johnson. The Intermuscular Bones and Ligaments of Teleostean Fishes. Smithsonian Contributions to Zoology, number 559, 85 pages, 16 figures, 2 plates, 8 tables, 1995.-Intermuscular bones are found only in teleostean fishes. They are segmental ossifications in the myosepta and generally are associated with ligaments. That association takes three forms: ontogenetic or structural continuity, when intermuscular bones ossify within ligament and/or are attached to the axial skeleton by ligament; serial homology, when a series of bones is continued rostrally or caudally by a series of ligaments; and homology, when a series of bones in one teleost is homologous with a series of ligaments in another. We recognize three series of intermusculars, epineurals, epicentrals, and epipleurals. Epineurals and epicentrals develop in a rostrocaudal gradient, whereas epipleurals develop rostrally and caudally from the region of the first caudal vertebra. We create a notation for recording the distribution and form of intermuscular bones and ligaments, and we map them in about 125 genera of teleosts from over 100 families, covering all major groups. The primitive state of Recent teleostean intermusculars is exemplified by Hiodon, in which all ossified epineurals are fused with the neural arches, and all epicentrals and epipleurals are ligaments. Some or all epineural bones are free (unfused) from the neural arches in other teleosts, and in many lower (nonacanthomorph) elopocephalans they develop an anteroventral branch so that they are forked proximally. Epineurals are primitively dorsolaterally directed, but the first one to three are deflected ventrally in a few nonacanthomorphs (argentinoids, some aulopiforms, Neoscopelus) and in lampridiform acanthomorphs. In Polymixia, the first epineural is displaced ventrally into the horizontal septum, and in all other acanthomorphs several or all epineurals are so displaced; the bones generally called epipleurals in acanthomorphs are epineurals. Epicentrals lie in the horizontal septum and are primitively ligamentous. There are ossified epicentrals in Notopterus, Megalops, clupeiforms, gonorynchiforms, gymnotoids, Thymallus, and the aulopiforms Parasudis, Alepisaurus, and Omosudis. Epicentral ligaments sometimes include a cartilage rod distally (salmonoids, osmeroids, Maurolicus, Polymixia), and in many clupeoids the distal tip of each anterior epicentral bone is associated with a separate superficial chevron of cartilage. Anterior epicentrals are lacking in some aulopiforms and among acanthomorphs in beryciforms, some zeiforms, and primitive percomorphs, so that the series of ligaments begins on the posterior abdominal vertebrae. All epicentrals are absent in some aulopiforms, in all examined paracanthopterygians and stephanoberyciforms, and in many percomorphs. A series of segmental, anterolaterally directed ligaments, "POTs," attaches to epicentrals in the horizontal septum of many teleosts. In percomorphs and zeiforms the anterior POTs acquire a new associat...

Osteología de Hippoglossina macrops (Pleuronectiformes, Paralichthyidae)

“…No hay desarrollo de apófisis transversas, tal como ocurre en otros Paralichthyidae como Citharichthys, Cyclopsetta, Etropus y Syacium (Hensley & Ahlstrom 1984, Murakami & Amaoka 1992 El extremo distal del hueso abdominal se encuentra fusionado con los dos primeros pterigióforos anales, a diferencia de Paralichthys en que sólo hay fusión del primer pterigióforo (Woolcott et al 1968). Hippoglossina macrops no presenta huesos intermusculares, tal como reportan Patterson & Johnson (1995) para Bothus (Bothidae) y Samaris (Samaridae).…”

The first record of Late Jurassic crossognathiform fishes from Europe and their phylogenetic importance for teleostean phylogeny

“…Bavarichthys presents an additional series of intermuscular bones (possible the "myorhabdoi" of Patterson & Johnson 1995) dorsal to the epineurals in the caudal region and an extra series of long epipleural bones posterior to the series of small epipleurals. Because there is not much available information about intermuscular bones in crossognathiforms the phylogenetic meaning of these features cannot be addressed at the present time.…”

“…6B) that extend dorsal to the epineural series in the epaxial musculature of the caudal region. These small thin bones may correspond to the elements named "myorhabdoi" by Patterson & Johnson (1995).…”

Interrelationships of Aulopiformes

“…To demonstrate the potential systematic value of the intermuscular ligaments and bones in teleostean fishes, Patterson and Johnson (1995) investigated aulopiform interrelationships based on this skeletal system. Their data provided support for a monophyletic Synodontoidei (sensu Johnson et ah, 1996) and a sistergroup relationship between evermannellids and scopelarchids.…”

“…Novel relationships depicted in their strict consensus of 24 equally parsimonious trees include the following: a clade comprising all aulopiform taxa except ipnopids (represented by Bathypterois in their analysis) and Parasudis; sister-group relationships between Chlorophthalmus and synodontoids, notosudids and the evermannellid-scopelarchid lineage, and bathysaurids and giganturids; and a paraphyletic Paralepididae, with Paralepis forming the sister group of a monophyletic clade comprising Omosudis and Alepisaurus. Patterson and Johnson (1995) noted that the paraphyly of the Paralepididae suggested by their data may be artificial, a result of the greatly reduced number of intermuscular elements in…”