Previous studies have shown that while hoxa2a of the Japanese medaka (Oryzias latipes) shows a conserved expression pattern in the hindbrain and PAs to other osteichthyan
Hoxa2 genes, medaka hoxa2b was shown to be a pseudogene, [psi]hoxa2b, which is expressed in non-canonical Hox PG2 domains, including the embryonic trunk and the pectoral fin buds.
A total of 90 marine and freshwater species belonging to 81 genera and 54 families were caught across the transect (9 chondrichthyan and 45 osteichthyan
Diogo (anthropology, George Washington University) presents a cladistic analysis of osteichthyan
higher-level interrelationships based on a phylogenetic comparison of 356 characters in 80 extent and fossil terminal taxa representing all major groups of Osteichthyes.
Schultze also supported Gross's position that Andreolepis is the most primitive actinopterygian and considered (Schultze 1996, p.222) Lophosteus the earliest osteichthyan
which cannot be placed among either the actinopterygians or sarcopterygians.
In September 2000, the author, digging in the streambed of the Ramanesson, collected the lower jaw of Gyrodus sp., an Osteichthyan
fish of the Family Pycnodontidae.
Pander in 1856, who described shields of the heterostracan Tolypelepis undulata, plates of the osteichthyan
Lophosteus superbus and a number of jaw bones of acanthodians (Pander 1856).
Although dominated by dinosaurs (reviewed by Martill and Naish, 2001), the assemblage includes chondrichthyan and osteichthyan
fishes, among which are hybodonts (Patterson, 1966), a neoselachian (Sweetman and Underwood, 2006), amiiforms, semionotiforms and pycnodontiforms (Woodward, 1889).
The Andreyevka-2 community including antiarch placoderms, acanthodians, chondrichthyans and osteichthyans
, as well as tetrapods, has been discussed on repeated occasions by the first author of this paper (Lebedev 1986, 1992, 2013; Lebedev et al.
Spatial organization and mineralization of the basal plate of elasmoid scales in osteichthyans