Cranial Remain from Tunisia Provides New Clues for the Origin and Evolution of Sirenia (Mammalia, Afrotheria) in Africa (original) (raw)
Figure 5
Simplified result of the cladistic analysis on sirenian petrosal and bony labyrinth characters (see also S1).
Strict consensus of 2975 trees. Tree length: 57; Consistency index (CI): 0.60; Retention index (RI):0.81; Homoplasy index (HI): 0.50; Rescaled consistency index (RC): 0.48. Bold lines represent fossil record. Geographic ranges of the sirenian from Chambi, prorastomids and other sirenians after refs. 3, 5, 12. Shared derived traits at nodes: Node 1: pachyosteosclerotic promontorium and tegmen tympani (3(1)); reniform tegmen tympani (11(1)); cochlear canal more voluminous than the vestibule (23(1), homoplasic, CI = 0.5); semicircular canals of approximately the same radius (25(1)); lateral canal larger than other canals (26(1)). Node 2: reduced stapedial ratio (round fenestra vestibuli) (5(1), homoplasic CI = 0.33); Hiatus fallopi absent (7(0), Homoplasic, CI = 0.33); Pseudotympanic facial foramen present (15(1)); inflated, squared (17(2)) and dense (19(1)) mastoid apophysis. Node 3: merged canaliculus cochleae and fenestra cochleae (4(1), homoplasic, CI = 0.33); weakly defined stapedial muscle fossa (10(1)); large and deep epitympanic recess (13(1)); developed epitympanic wing (16(1), homoplasic, CI = 0.2); Thick crista falciformis widely separating the acoustic foramina (20(1), homoplasic, CI = 0.50). Node 4: tegmen process present (12(1), homoplasic, CI = 0.5).