Revision of the cranial anatomy and phylogenetic relationships of the Eocene minute boas Messelophis variatus and Messelophis ermannorum (Serpentes, Booidea)

AGUSTÍN SCANFERLA; KRISTER SMITH; STEPHAN SCHAAL

ZOOLOGICAL JOURNAL OF THE LINNEAN SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2016 vol. 176 p. 182 - 206

0024-4082

<!-- /* Font Definitions */@font-face{font-family:"ＭＳ 明朝";mso-font-charset:78;mso-generic-font-family:auto;mso-font-pitch:variable;mso-font-signature:-536870145 1791491579 18 0 131231 0;}@font-face{font-family:"Cambria Math";panose-1:2 4 5 3 5 4 6 3 2 4;mso-font-charset:0;mso-generic-font-family:auto;mso-font-pitch:variable;mso-font-signature:-536870145 1107305727 0 0 415 0;}@font-face{font-family:Cambria;panose-1:2 4 5 3 5 4 6 3 2 4;mso-font-charset:0;mso-generic-font-family:auto;mso-font-pitch:variable;mso-font-signature:-536870145 1073743103 0 0 415 0;} /* Style Definitions */p.MsoNormal, li.MsoNormal, div.MsoNormal{mso-style-unhide:no;mso-style-qformat:yes;mso-style-parent:"";margin:0cm;margin-bottom:.0001pt;mso-pagination:widow-orphan;font-size:12.0pt;font-family:Cambria;mso-ascii-font-family:Cambria;mso-ascii-theme-font:minor-latin;mso-fareast-font-family:"ＭＳ 明朝";mso-fareast-theme-font:minor-fareast;mso-hansi-font-family:Cambria;mso-hansi-theme-font:minor-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:minor-bidi;}.MsoChpDefault{mso-style-type:export-only;mso-default-props:yes;font-family:Cambria;mso-ascii-font-family:Cambria;mso-ascii-theme-font:minor-latin;mso-fareast-font-family:"ＭＳ 明朝";mso-fareast-theme-font:minor-fareast;mso-hansi-font-family:Cambria;mso-hansi-theme-font:minor-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:minor-bidi;}@page WordSection1{size:612.0pt 792.0pt;margin:70.85pt 3.0cm 70.85pt 3.0cm;mso-header-margin:36.0pt;mso-footer-margin:36.0pt;mso-paper-source:0;}div.WordSection1{page:WordSection1;}-->We provide a detailed anatomical description of the skull ofthe fossil minute boas Messelophis variatus Baszio, 2004 and Messelophisermannorum Schaal & Baszio, 2004 from the Middle Eocene Messel Formation(Germany), as well as a cladistic analysis to infer their phylogeneticrelationships. Reanalysis of new and known specimens of both speciesdemonstrates previously unrecognized anatomical characters in the skull ofthese fossil snakes. Both morphological and combined (morphology plus DNA)analyses place both species of Messelophis within a clade composed of boine,ungaliophiine, and erycine taxa. Cranial features that support this systematicarrangement include a well-developed medial foot process of the prefrontal, anexpanded lateral flange of the prefrontal, and a well-developed surangularcrest of the compound bone, among others. As a result of the incompleteness ofsome crucial cranial regions, such as the basicranium, their exactrelationships within this clade are currently unresolved. Messelophis speciesdisplay several contrasting traits that greatly exceed the morphologicaldisparity found among extant genera of snakes. This cranial and postcranialanatomical variation between M. variatus and M. ermannorum demonstrates thatthis last species should be allocated to a new genus. Rieppelophis gen. nov. istherefore erected for the species Rieppelophis ermannorum comb. nov.