. Bulletin of the British Museum (Natural History), Geology. metd entd. endoloph B ectolophid Text-figure 31 Dental nomenclature of pseudosciurid cheek teeth. A, left upper molar. Buccal edge towards top of page, lingual towards bottom. B, left lower molar. Buccal edge towards bottom of page, lingual towards top. Abbreviations: A. antph—anteroloph hyp—hypocone hypphle—hypolophule hypst—hypostyle mes—mesocone mesph—mesoloph (partial) mest—mesostyle met—metacone metle 1—metaconule 1 metle 2—metaconule 2 par—paracone parle—paraconule past—parastyle postph—posteroloph prost—protostyle ( = anteroco
. Bulletin of the British Museum (Natural History), Geology. metd entd. endoloph B ectolophid Text-figure 31 Dental nomenclature of pseudosciurid cheek teeth. A, left upper molar. Buccal edge towards top of page, lingual towards bottom. B, left lower molar. Buccal edge towards bottom of page, lingual towards top. Abbreviations: A. antph—anteroloph hyp—hypocone hypphle—hypolophule hypst—hypostyle mes—mesocone mesph—mesoloph (partial) mest—mesostyle met—metacone metle 1—metaconule 1 metle 2—metaconule 2 par—paracone parle—paraconule past—parastyle postph—posteroloph prost—protostyle ( = anterocone) prot—protocone B. antd—anteroconid antphd—anterolophid antphld—anterolophulid ectstd—ectostylid entd—entoconid hypd—hypoconid hypld—hypoconulid hypphld—hypolophulid mesd—mesoconid mesphd—mesolophid (partial mestd—mesostylid metd—metaconid metphld—metalophulid postphd—posterolophid protd—protoconid Paramyidae (see Hartenberger 1969: 56). No evidence is forthcoming on these questions from the English Bartonian material. Suffice to say that theridomyoids are hystricomorphous and sciurognathous and have cheek teeth which range from low-crowned to moderately high- crowned but always retain the roots. The complexities of convergence in hystricomorphy are discussed by Wood & Patterson (1970). Their dental formula is j q \ I but sometimes DPf is retained and not replaced by Pf. They have usually been divided into two families: the Pseudosciuridae Zittel 1893 for the lower-crowned and Theridomyidae Alston 1876 for the higher-crowned types. However, Har- tenberger (1971) produced a model of parallel evolution of higher-crowned forms (which would have been classified as theridomyids) from new (Estellomys) and hypothetical lower-crowned forms (which would have been classified as pseudosciurids or as transitions between the two families). He assimilated the two families under the name Theridomyidae which he divided into s
Size: 1864px × 1341px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorbritishmuseumnaturalhistory, bookcentury1900, bookcoll
