Gliridae, Muirhead, 1819

Pfaff, Cathrin, Martin, Thomas & Ruf, Irina, 2015, BSeptal compass ^ and Bseptal formula ^: a new method for phylogenetic investigations of the middle ear region in the squirrel-related clade (Rodentia: Mammalia), Organisms Diversity & Evolution (New York, N. Y.) 15 (4), pp. 721-730 : 726

Gliridae

None of the investigated taxa of glirids possesses septa in the epitympanic recess ( Fig. 3 ; Table S2). The ancestral character state of the septa distribution for glirids are the primary ventrally lying septa I to III and the secondary septum a (>Re -/a,I, II,III pmd). The appearance of the posterior medial diverticulum (pmd) is coded as two character states (present, absent). The number of bony septa and the occurrence of a posterior medial diverticulum distinguish three groups of middle ear cavities within this group:

Group I: Glis glis is characterized by three ventrally positioned primary septa (>Re -/a,I,II,III; Fig. S2 B, C ).

Group II: The investigated specimens of Eliomys quercinus , Dryomys nitedula intermedius , and Graphiurus parvus (Table S2, Fig. S2 D, E ) show the same pattern as G. glis . Additionally, these species possess a posterior diverticulum, similar to the condition found in Muscardinus avellanarius .

Group III: The middle ear cavity of M. avellanarius houses four primary septa in the tympanic cavity and has an additional posterior diverticulum (>Re -/a,I,II,III,IV pmd; Fig. S3 A, B ).

Figures

Fig. 3 Patterns of Bprimary septa^ and Bsecondary septa^ in the epitympanic recess and the tympanic cavity in the squirrel-related clade, †Palaeosciurus feignouxi, †Ischyromys typus, and investigated outgroups: pmd posterior medial diverticulum, filled square character present, white square character absent, question mark character not preserved. Species of investigated glirids: group I:= Glis glis; group II= Dryomys nitedula intermedius, Eliomys quercinus, and Graphiurus parvus; group III=Muscardinus avellanarius. Schemas of septal compass

Fig. 2 Septal compass: general graphical illustration of the anatomy of the right middle ear region with the relative position of the primary septa (I–III) and the secondary septa (A, B, a). One asterisk (a*) indicates the Blateral secondary septum^ of MacPhee (1981), two asterisks (**) indicate the Banterior septum^ of Wible (2009). cty cavum tympani (=tympanic cavity), fsa fossa subarcuata (=subarcuate fossa), rec recessus epitympanicus (=epitympanic recess)