Figure 1.
Location map of the primate-bearing Chambi locus 1 locality (CBI-1) in Tunisia.
A, map of Tunisia locating the Natural Park of Djebel Chambi, a mountain situated in the western part of Central Tunisia (Kasserine region); B, geological map of Djebel Chambi (modified after Hartenberger et al. [42]) showing the position of the fossiliferous CBI-1 locality in the Eocene deposits (white “F” in a black filled circle); C, landscape photograph of the lacustrine limestone bed (freshwater deposits), which has yielded CBI-1; D, photograph of the indurated limestone bed of CBI-1 showing a fossiliferous spot (Pictures by Laurent Marivaux); E, temporal distribution of primate-bearing localities from the Paleogene of Afro-Arabia (modified after Seiffert [38] and Coster et al. [64]).
Figure 2.
Upper and lower jaws of Djebelemur martinezi from the Djebel Chambi CBI-1 locality.
A, outline of the CBI-1-565 maxilla in occlusal view; B, outline of the CBI-133 mandible (holotype) in occlusal; C, drawings of the upper toothrow (left P3-M3) of CBI-1-565; D, drawings of the lower toothrow (left p3-m3) of CBI-1-33. Scale bars: 1 mm. Original scientific drawings by Laurence Meslin (© CNRS-Meslin).
Figure 3.
Lower jaw of Djebelemur martinezi from the Djebel Chambi CBI-1 locality.
A, CBI-1-565, fragments of right mandible, which consists of three isolated pieces found together and reassembled here: the anterior part of the dentary bears the p3 and m1, and alveoli for p4, p2 and c, while the posterior part preserves m3 and a portion of the ascending ramus; m2 was found isolated but in the same small calcareous block treated by acid processing; B, photograph of the proximal part of CBI-1-565 (for p4 and p3, note that their mesial alveolus is slightly offset buccally with respect to their distal alveolus; the single alveolus for p2 is mesiodistally compressed and oblique, while the alveolus for the canine, although only partially preserved, appears slightly larger, suboval, and more lingually positioned with respect to the main axis of the toothrow). C–G, composite lower toothrow with the CBI-1-565 mandible, CBI-1-580 canine (reversed), CBI-1-587 p2 (reversed), and CBI-1-577 p4, in occlusal (C), lingual (D), frontal (F), and distal (G) views; H, CBI-1-587, left p2 in (from left to right) occlusal, buccal, lingual, distal, and mesial views (not reversed); I, CBI-1-580, left canine in (from left to right) occlusal, buccal, lingual, distal, and mesial views (not reversed). The 3D representations of CBI-1-565 (A, C–G), CBI-1-587 (H), and CBI-1-580 (I) have been obtained by X-ray µCT surface reconstruction. The crown and roots of teeth of the mandible have been virtually delimited by manual segmentation.
Figure 4.
Facial fragment of Djebelemur martinezi from the Djebel Chambi CBI-1 locality.
A–E, CBI-1-544, left maxilla preserving P3-M3 and alveoli for P2 and C1, in frontal (A), coronal section (cs) through M1 (B), palatal (C), dorsal (D), and lateral (E) views; F, CBI-1-567, left P4 in occlusal view. The 3D representations of CBI-1-544 and CBI-1-567 have been obtained by X-ray µCT surface reconstruction. On the maxilla, the crown and roots of teeth have been virtually delimited by manual segmentation. Abbreviations: IOF, infraorbital foramen; of, orbital floor; hp, hard palate; pzm, processus zygomaticus maxillae; ra, root apex; jms, jugo-maxillary suture.
Figure 5.
Comparative high-resolution micro-CT scans of the maxilla through the distal root of M1 in some selected nocturnal versus diurnal primates.
Microcebus, Cheirogaleus, Avahi, Loris, Euoticus, Aotus and Tarsius are nocturnal primates, while Cebus and Lemur are diurnal (Adapis was most likely diurnal). The red arrows indicate the orbital floor, and the yellow bars provide an approximation of the suborbital depth of the maxilla. Scale bars: 1 mm.
Figure 6.
Ankle bone (or talus) of primate from the Djebel Chambi CBI-1 locality.
A–F, CBI-1-545, right talus in dorsal (A), ventral (B), proximal (C), distal (D), lateral (E), and medial (F) views. The oblique white line (C and D) indicates the slope of the lateral talofibular facet. The white arrow (D) indicates the passage of the flexor hallucis longus tendon. The images are 3D digital models of the CBI-1-545 talus, which have been obtained by X-ray µCT surface reconstruction.
Table 1.
Measurements (in millimetres) of upper and lower teeth of Djebelemur martinezi from the Djebel Chambi CBI-1 locality.
Table 2.
Metric features (in millimetres) of the CBI-1-545 talus from the Djebel Chambi CBI-1 locality.
Figure 7.
Phylogenetic position of Djebelemur in a high-level primate phylogeny with a cladistic assessment of the craniodental and postcranial evidence performed without molecular scaffold.
A–C, consensus trees (A, Strict; B, Majority Rule at 80%) of 3426 equally most-parsimonious trees of 3886 steps each (CI = 0.147; RI = 0.566), which were obtained after analyses performed considering some multistate characters as ordered (i.e., if changes from one state to another require passing through intermediate states); C, consensus tree (Majority Rule at 80%) of 64 equally most-parsimonious trees of 3593 steps each (CI = 0.159; RI = 0.542), which were obtained after analyses performed considering all characters as unordered. On the Majority Rule consensus trees (B and C), the values above or below the nodes correspond to the rates (%) of node occurrences across the whole equally most-parsimonious trees found.
Figure 8.
Phylogenetic position of Djebelemur in a high-level primate phylogeny with a cladistic assessment of the craniodental and postcranial evidence performed with a molecular scaffold.
A–B, consensus trees (A, Strict; B, Majority Rule at 60%) of 506 equally most-parsimonious trees of 3903 steps each (CI = 0.147; RI = 0.564), which were obtained after analyses performed considering some ordered characters; C, consensus tree (Majority Rule at 80%) of 116 equally most-parsimonious trees of 3608 steps each (CI = 0.158; RI = 0.539), which were obtained after analyses performed considering all characters unordered. The molecular scaffold [47] was used to recover those primate clades that are supported by genomic sequences. This gene-based tree of modern taxa (Perelman et al. [28]) strongly supports the monophyly of Malagasy Lemuriformes (including a Lemuridae clade, a Lepilemur-Cheirogaleidae clade, and an Indriidae clade) and that of the Lorisiformes (including a Galagidae clade and a Lorisidae clade with an Arctocebus-Perodicticus subclade and a Loris-Nycticebus subclade). On the Majority Rule consensus trees (B and C), the values above or below the nodes correspond to the rates (%) of node occurrences across the whole equally most-parsimonious trees found. The molecular scaffold used here is as follows [28]: (Scandentia, ((((Varecia, (Eulemur, (Lemur, Hapalemur))), (Lepilemur, (Cheirogaleus, (Microcebus, Mirza))), (Propithecus, Avahi)), (((Loris, Nycticebus), (Perodicticus, Arctocebus)), (Galago, Otolemur))), (Tarsius, (Saimiri, Aotus)))).
Figure 9.
Comparison of the shearing quotients (SQ) of the different Eocene strepsirhine primates (non Adapiformes) from Africa.
For each taxon, the SQ value is the ratio of m2 length to summed lengths of six principal m2 shearing crests [53], [54]. Color-coded bars (blue, insects; green, leaves; red, fruit and gums) indicate principal dietary item for extant strepsirhine taxa [54]. Low values indicate a diet based on fruit, gums or even seeds, whereas a high SQ points towards a leaf or insect based diet.
Figure 10.
Linear discriminant analysis (LDA) based on dental microwear, shearing quotients and body mass estimations for extant strepsirhines and Djebelemur martinezi.
Extant specimens are distinguished according to family: Cheirogaleidae (Cheirogaleus major, Ch. Medius, Microcebus murinus), Galagidae (Galago senegalensis, Euoticus elegantulus), Indriidae (Propithecus verreauxi), Lemuridae (Eulemur fulvus, Hapalemur griseus), Lepilemuridae (Lepilemur ruficaudatus), Lorisidae (Perodicticus potto, Arctocebus calabarensis, Loris tardigradus), and Tarsiidae (Tarsius spectrum). Dietary categories, generated by data on extant taxa, are delimited by LDA decision boundaries (dotted lines): leaf-eating is in green; fruit-eating in red; insect-eating in blue; gum-eating in yellow [61]. Photographs situated on the top of this figure are digitized images of microwear patterns for each dietary category and Djebelemur martinezi (top right: detail of the crushing facet of the protocone captured on the M2 of CBI-1-544). Photos were taken at 100 x using an optical stereomicroscope (Leica M 205C) connected to a camera (Leica DFC 420C). Scale bar = 100 µm.