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Notes on Some Annexa Oculi in the Osteolepiform Freshwater Fish Eusthenopteron foordi from the Upper Devonian Escuminac Formation of Miguasha, Eastern Canada
Author(s) -
Bjerring Hans C.
Publication year - 1987
Publication title -
acta zoologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.414
H-Index - 37
eISSN - 1463-6395
pISSN - 0001-7272
DOI - 10.1111/j.1463-6395.1987.tb00888.x
Subject(s) - biology , anatomy , devonian , extant taxon , fish <actinopterygii> , operculum (bryozoa) , zoology , genus , paleontology , fishery , evolutionary biology
The orbit of the Upper Devonian piscine osteolepipod Eusthenopteron foordi has a distinct endocranial depression postero‐ventrally at the base of the basipterygoid process and lateral to the hypophysis. Compared with what is known of extant osteolepipods, this depression is a myodomus retractricis bulbi. From the evidence of this myodome for attachment of retractor bulbi musculature, the hypothesis is presented that Eusthenopteron foordi had a palpebra tertia and, as a corollary, that it also had a musculus levator bulbi, a glandula palpebrae tertiae and a ductus nasolacrimalis. These annexal eye structures would have made it possible for this pulmonate fish to leave the water to bask without being dazzled by sunlight.