Species Eosuchus

lower jaw of holotype

the name eosuchus first used in 1907 describe single specimen found northern france near belgian border, assigned type species e. lerichei.

a new species of gavialis, g. minor, named othniel charles marsh in 1870 on basis of holotype specimen ypm 282, consisting of cranial fragments , isolated vertebrae found manasquan formation in monmouth county, new jersey. locality dates ypresian stage of eocene. species name refers relatively small estimated size of animal, estimated @ no more 2 meters, when compared other gavialoids such modern gharial, can grow 5 meters in length.

however, species later recognized distinct gavialis on basis of aspects of known cranial material, in particular large foramen aerum of quadrate formed epithelial tube connects pneumatic chambers of quadrate , articular. diagnostic feature thought distinguish species gavialis narrow interfenestral bar of parietal bone relatively smooth , unsculptured when compared other gavialoids such thoracosaurus. name thecachampsoides proposed species g. minor in 1986. close relationship between t. minor , eosuchus lerichei evident, yet not until 2006 name eosuchus applied t. minor specimens, on basis of complete specimen called njsm 15437 vincetown formation in new jersey, of there visibly exposed braincase aids in taxonomic classification of genus. examination of specimens of t. minor of e. lerichei yielded many similarities between 2 species, including foramen aerum other features such long nasal process between premaxillae, dentary alvioli arranged in pairs, , w-shaped basioccipital tuberosity. e. minor differs e. lerichei on basis of noticeably wider nasal , prefrontals positioned anteriorly further skull lacrimals.

other material present aquia formation of maryland , virginia, dates paleocene, tends more complete. specimens found these localities known complete skulls provide more detailed view of phylogenetic position of eosuchus, , further aid in distinguishing e. minor other gavialoids.

historically, many other species of extinct gavialoids have been assigned genus gavialis (of modern gharial, g. gangeticus, member of). these include forms such thoracosaurus.